Smartphone Microscopy of Parasite Eggs Accumulated into a Single Field of View

PubMed Central

Sowerby, Stephen J.; Crump, John A.; Johnstone, Maree C.; Krause, Kurt L.; Hill, Philip C.

2016-01-01

A Nokia Lumia 1020 cellular phone (Microsoft Corp., Auckland, New Zealand) was configured to image the ova of Ascaris lumbricoides converged into a single field of view but on different focal planes. The phone was programmed to acquire images at different distances and, using public domain computer software, composite images were created that brought all the eggs into sharp focus. This proof of concept informs a framework for field-deployable, point of care monitoring of soil-transmitted helminths. PMID:26572870

Prior task experience and comparable stimulus exposure nullify focal and nonfocal prospective memory retrieval differences.

PubMed

Hicks, Jason L; Franks, Bryan A; Spitler, Samantha N

2017-10-01

We explored the nature of focal versus nonfocal event-based prospective memory retrieval. In the context of a lexical decision task, people received an intention to respond to a single word (focal) in one condition and to a category label (nonfocal) for the other condition. Participants experienced both conditions, and their order was manipulated. The focal instruction condition was a single word presented multiple times. In Experiment 1, the stimuli in the nonfocal condition were different exemplars from a category, each presented once. In the nonfocal condition retrieval was poorer and reaction times were slower during the ongoing task as compared to the focal condition, replicating prior findings. In Experiment 2, the stimulus in the nonfocal condition was a single category exemplar repeated multiple times. When this single-exemplar nonfocal condition followed in time the single-item focal condition, focal versus nonfocal performance was virtually indistinguishable. These results demonstrate that people can modify their stimulus processing and expectations in event-based prospective memory tasks based on experience with the nature of prospective cues and with the ongoing task.

The correction of aberrations computed in the aperture plane of multifrequency microwave radiometer antennas

NASA Technical Reports Server (NTRS)

Schmidt, R. F.

1984-01-01

An analytical/numerical approach to identifying and correcting the aberrations introduced by a general displacement of the feed from the focal point of a single offset paraboloid antenna used in deployable radiometer systems is developed. A 15 meter reflector with 18 meter focal length is assumed for the analysis, which considers far field radiation pattern quality, focal region fields, and aberrations appearing in the aperture plane. The latter are obtained by ray tracing in the transmit mode and are expressed in terms of optical notation. Attention is given to the physical restraints imposed on corrective elements by real microwave systems and to the intermediate near field aspects of the problem in three dimensions. The subject of wave fronts and caustics in the receive mode is introduced for comparative purposes. Several specific examples are given for aberration reduction at eight beamwidths of scan at a frequency of 1.414 GHz.

Predicting Students' Skills in the Context of Scientific Inquiry with Cognitive, Motivational, and Sociodemographic Variables

ERIC Educational Resources Information Center

Nehring, Andreas; Nowak, Kathrin H.; zu Belzen, Annette Upmeier; Tiemann, Rüdiger

2015-01-01

Research on predictors of achievement in science is often targeted on more traditional content-based assessments and single student characteristics. At the same time, the development of skills in the field of scientific inquiry constitutes a focal point of interest for science education. Against this background, the purpose of this study was to…

Smartphone Microscopy of Parasite Eggs Accumulated into a Single Field of View.

PubMed

Sowerby, Stephen J; Crump, John A; Johnstone, Maree C; Krause, Kurt L; Hill, Philip C

2016-01-01

A Nokia Lumia 1020 cellular phone (Microsoft Corp., Auckland, New Zealand) was configured to image the ova of Ascaris lumbricoides converged into a single field of view but on different focal planes. The phone was programmed to acquire images at different distances and, using public domain computer software, composite images were created that brought all the eggs into sharp focus. This proof of concept informs a framework for field-deployable, point of care monitoring of soil-transmitted helminths. © The American Society of Tropical Medicine and Hygiene.

An automated optimization tool for high-dose-rate (HDR) prostate brachytherapy with divergent needle pattern

NASA Astrophysics Data System (ADS)

Borot de Battisti, M.; Maenhout, M.; de Senneville, B. Denis; Hautvast, G.; Binnekamp, D.; Lagendijk, J. J. W.; van Vulpen, M.; Moerland, M. A.

2015-10-01

Focal high-dose-rate (HDR) for prostate cancer has gained increasing interest as an alternative to whole gland therapy as it may contribute to the reduction of treatment related toxicity. For focal treatment, optimal needle guidance and placement is warranted. This can be achieved under MR guidance. However, MR-guided needle placement is currently not possible due to space restrictions in the closed MR bore. To overcome this problem, a MR-compatible, single-divergent needle-implant robotic device is under development at the University Medical Centre, Utrecht: placed between the legs of the patient inside the MR bore, this robot will tap the needle in a divergent pattern from a single rotation point into the tissue. This rotation point is just beneath the perineal skin to have access to the focal prostate tumor lesion. Currently, there is no treatment planning system commercially available which allows optimization of the dose distribution with such needle arrangement. The aim of this work is to develop an automatic inverse dose planning optimization tool for focal HDR prostate brachytherapy with needle insertions in a divergent configuration. A complete optimizer workflow is proposed which includes the determination of (1) the position of the center of rotation, (2) the needle angulations and (3) the dwell times. Unlike most currently used optimizers, no prior selection or adjustment of input parameters such as minimum or maximum dose or weight coefficients for treatment region and organs at risk is required. To test this optimizer, a planning study was performed on ten patients (treatment volumes ranged from 8.5 cm3to 23.3 cm3) by using 2-14 needle insertions. The total computation time of the optimizer workflow was below 20 min and a clinically acceptable plan was reached on average using only four needle insertions.

Experimental validation of a newly designed 6 degrees of freedom scanning laser head: Application to three-dimensional beam structure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Di Maio, D., E-mail: dario.dimaio@bristol.ac.uk; Copertaro, E.

2013-12-15

A new scanning laser head is designed to use single Laser Doppler Vibrometer (LDV) for performing measurements up to 6 degrees of freedom (DOF) at a target. The scanning head is supported by a rotating hollow shaft, which allows the laser beam to travel up to the scanning head from an opposite direction where an LDV is set up. The scanning head is made of a set of two mirrors, which deflects the laser beam with an angle so that the rotation of the scanning head produces a conical scan. When measurements are performed at the focal point of themore » conical scan then three translational vibration components can be measured, otherwise the very small circle scan, before and after the focal point, can measure up to 6 degrees of freedom, including three translations and three rotations. This paper presents the 6DOF scanning head and the measurements of 3D operational deflection shapes of a test structure.« less

Numerical study and ex vivo assessment of HIFU treatment time reduction through optimization of focal point trajectory

NASA Astrophysics Data System (ADS)

Grisey, A.; Yon, S.; Pechoux, T.; Letort, V.; Lafitte, P.

2017-03-01

Treatment time reduction is a key issue to expand the use of high intensity focused ultrasound (HIFU) surgery, especially for benign pathologies. This study aims at quantitatively assessing the potential reduction of the treatment time arising from moving the focal point during long pulses. In this context, the optimization of the focal point trajectory is crucial to achieve a uniform thermal dose repartition and avoid boiling. At first, a numerical optimization algorithm was used to generate efficient trajectories. Thermal conduction was simulated in 3D with a finite difference code and damages to the tissue were modeled using the thermal dose formula. Given an initial trajectory, the thermal dose field was first computed, then, making use of Pontryagin's maximum principle, the trajectory was iteratively refined. Several initial trajectories were tested. Then, an ex vivo study was conducted in order to validate the efficicency of the resulting optimized strategies. Single pulses were performed at 3MHz on fresh veal liver samples with an Echopulse and the size of each unitary lesion was assessed by cutting each sample along three orthogonal planes and measuring the dimension of the whitened area based on photographs. We propose a promising approach to significantly shorten HIFU treatment time: the numerical optimization algorithm was shown to provide a reliable insight on trajectories that can improve treatment strategies. The model must now be improved in order to take in vivo conditions into account and extensively validated.

Influence of the distance between target surface and focal point on the expansion dynamics of a laser-induced silicon plasma with spatial confinement

NASA Astrophysics Data System (ADS)

Zhang, Dan; Chen, Anmin; Wang, Xiaowei; Wang, Ying; Sui, Laizhi; Ke, Da; Li, Suyu; Jiang, Yuanfei; Jin, Mingxing

2018-05-01

Expansion dynamics of a laser-induced plasma plume, with spatial confinement, for various distances between the target surface and focal point were studied by the fast photography technique. A silicon wafer was ablated to induce the plasma with a Nd:YAG laser in an atmospheric environment. The expansion dynamics of the plasma plume depended on the distance between the target surface and focal point. In addition, spatially confined time-resolved images showed the different structures of the plasma plumes at different distances between the target surface and focal point. By analyzing the plume images, the optimal distance for emission enhancement was found to be approximately 6 mm away from the geometrical focus using a 10 cm focal length lens. This optimized distance resulted in the strongest compression ratio of the plasma plume by the reflected shock wave. Furthermore, the duration of the interaction between the reflected shock wave and the plasma plume was also prolonged.

Anisotropic forces from spatially constrained focal adhesions mediate contact guidance directed cell migration

PubMed Central

Ray, Arja; Lee, Oscar; Win, Zaw; Edwards, Rachel M.; Alford, Patrick W.; Kim, Deok-Ho; Provenzano, Paolo P.

2017-01-01

Directed migration by contact guidance is a poorly understood yet vital phenomenon, particularly for carcinoma cell invasion on aligned collagen fibres. We demonstrate that for single cells, aligned architectures providing contact guidance cues induce constrained focal adhesion maturation and associated F-actin alignment, consequently orchestrating anisotropic traction stresses that drive cell orientation and directional migration. Consistent with this understanding, relaxing spatial constraints to adhesion maturation either through reduction in substrate alignment density or reduction in adhesion size diminishes the contact guidance response. While such interactions allow single mesenchymal-like cells to spontaneously ‘sense' and follow topographic alignment, intercellular interactions within epithelial clusters temper anisotropic cell–substratum forces, resulting in substantially lower directional response. Overall, these results point to the control of contact guidance by a balance of cell–substratum and cell–cell interactions, modulated by cell phenotype-specific cytoskeletal arrangements. Thus, our findings elucidate how phenotypically diverse cells perceive ECM alignment at the molecular level. PMID:28401884

Single scan femtosecond laser transverse writing of depressed cladding waveguides enabled by three-dimensional focal field engineering.

PubMed

Zhang, Qian; Yang, Dong; Qi, Jia; Cheng, Ya; Gong, Qihuang; Li, Yan

2017-06-12

We report single scan transverse writing of depressed cladding waveguides inside ZBLAN glass with the longitudinally oriented annular ring-shaped focal intensity distribution of the femtosecond laser. The entire region of depressed cladding at the cross section, where a negative change of refraction index is induced, can be modified simultaneously with the ring-shaped focal intensity profile. The fabricated waveguides exhibit good single guided mode.

Enchanced interference cancellation and telemetry reception in multipath environments with a single paraboic dish antenna using a focal plane array

NASA Technical Reports Server (NTRS)

Vilnrotter, Victor A. (Inventor); Mukai, Ryan (Inventor)

2011-01-01

An Advanced Focal Plane Array ("AFPA") for parabolic dish antennas that exploits spatial diversity to achieve better channel equalization performance in the presence of multipath (better than temporal equalization alone), and which is capable of receiving from two or more sources within a field-of-view in the presence of multipath. The AFPA uses a focal plane array of receiving elements plus a spatio-temporal filter that keeps information on the adaptive FIR filter weights, relative amplitudes and phases of the incoming signals, and which employs an Interference Cancelling Constant Modulus Algorithm (IC-CMA) that resolves multiple telemetry streams simultaneously from the respective aero-nautical platforms. This data is sent to an angle estimator to calculate the target's angular position, and then on to Kalman filters FOR smoothing and time series prediction. The resulting velocity and acceleration estimates from the time series data are sent to an antenna control unit (ACU) to be used for pointing control.

Effect of defocusing on laser ablation plume observed by laser-induced fluorescence imaging spectroscopy

NASA Astrophysics Data System (ADS)

Oba, Masaki; Miyabe, Masabumi; Akaoka, Katsuaki; Wakaida, Ikuo

2016-02-01

We used laser-induced fluorescence imaging with a varying beam focal point to observe ablation plumes from metal and oxide samples of gadolinium. The plumes expand vertically when the focal point is far from the sample surface. In contrast, the plume becomes hemispherical when the focal point is on the sample surface. In addition, the internal plume structure and the composition of the ablated atomic and ionic particles also vary significantly. The fluorescence intensity of a plume from a metal sample is greater than that from an oxide sample, which suggests that the number of monatomic species produced in each plume differs. For both the metal and oxide samples, the most intense fluorescence from atomic (ionic) species is observed with the beam focal point at 3-4 mm (2 mm) from the sample surface.

Force direction patterns promote whole body stability even in hip-flexed walking, but not upper body stability in human upright walking

NASA Astrophysics Data System (ADS)

Müller, Roy; Rode, Christian; Aminiaghdam, Soran; Vielemeyer, Johanna; Blickhan, Reinhard

2017-11-01

Directing the ground reaction forces to a focal point above the centre of mass of the whole body promotes whole body stability in human and animal gaits similar to a physical pendulum. Here we show that this is the case in human hip-flexed walking as well. For all upper body orientations (upright, 25°, 50°, maximum), the focal point was well above the centre of mass of the whole body, suggesting its general relevance for walking. Deviations of the forces' lines of action from the focal point increased with upper body inclination from 25 to 43 mm root mean square deviation (RMSD). With respect to the upper body in upright gait, the resulting force also passed near a focal point (17 mm RMSD between the net forces' lines of action and focal point), but this point was 18 cm below its centre of mass. While this behaviour mimics an unstable inverted pendulum, it leads to resulting torques of alternating sign in accordance with periodic upper body motion and probably provides for low metabolic cost of upright gait by keeping hip torques small. Stabilization of the upper body is a consequence of other mechanisms, e.g. hip reflexes or muscle preflexes.

RF/optical shared aperture for high availability wideband communication RF/FSO links

DOEpatents

Ruggiero, Anthony J; Pao, Hsueh-yuan; Sargis, Paul

2014-04-29

An RF/Optical shared aperture is capable of transmitting and receiving optical signals and RF signals simultaneously. This technology enables compact wide bandwidth communications systems with 100% availability in clear air turbulence, rain and fog. The functions of an optical telescope and an RF reflector antenna are combined into a single compact package by installing an RF feed at either of the focal points of a modified Gregorian telescope.

RF/optical shared aperture for high availability wideband communication RF/FSO links

DOEpatents

Ruggiero, Anthony J; Pao, Hsueh-yuan; Sargis, Paul

2015-03-24

An RF/Optical shared aperture is capable of transmitting and receiving optical signals and RF signals simultaneously. This technology enables compact wide bandwidth communications systems with 100% availability in clear air turbulence, rain and fog. The functions of an optical telescope and an RF reflector antenna are combined into a single compact package by installing an RF feed at either of the focal points of a modified Gregorian telescope.

Ground-based remote sensing with long lens video camera for upper-stem diameter and other tree crown measurements

Treesearch

Neil A. Clark; Sang-Mook Lee

2004-01-01

This paper demonstrates how a digital video camera with a long lens can be used with pulse laser ranging in order to collect very large-scale tree crown measurements. The long focal length of the camera lens provides the magnification required for precise viewing of distant points with the trade-off of spatial coverage. Multiple video frames are mosaicked into a single...

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Dual-element transducer with phase-inversion for wide depth of field in high-frequency ultrasound imaging.

PubMed

Jeong, Jong Seob

2014-08-05

In high frequency ultrasound imaging (HFUI), the quality of focusing is deeply related to the length of the depth of field (DOF). In this paper, a phase-inversion technique implemented by a dual-element transducer is proposed to enlarge the DOF. The performance of the proposed method was numerically demonstrated by using the ultrasound simulation program called Field-II. A simulated dual-element transducer was composed of a disc- and an annular-type elements, and its aperture was concavely shaped to have a confocal point at 6 mm. The area of each element was identical in order to provide same intensity at the focal point. The outer diameters of the inner and the outer elements were 2.1 mm and 3 mm, respectively. The center frequency of each element was 40 MHz and the f-number (focal depth/aperture size) was two. When two input signals with 0° and 180° phases were applied to inner and outer elements simultaneously, a multi-focal zone was generated in the axial direction. The total -6 dB DOF, i.e., sum of two -6 dB DOFs in the near and far field lobes, was 40% longer than that of the conventional single element transducer. The signal to noise ratio (SNR) was increased by about two times, especially in the far field. The point and cyst phantom simulation were conducted and their results were identical to that of the beam pattern simulation. Thus, the proposed scheme may be a potential method to improve the DOF and SNR in HFUI.

Variable Magnification With Kirkpatrick-Baez Optics for Synchrotron X-Ray Microscopy

PubMed Central

Jach, Terrence; Bakulin, Alex S.; Durbin, Stephen M.; Pedulla, Joseph; Macrander, Albert

2006-01-01

We describe the distinction between the operation of a short focal length x-ray microscope forming a real image with a laboratory source (convergent illumination) and with a highly collimated intense beam from a synchrotron light source (Köhler illumination). We demonstrate the distinction with a Kirkpatrick-Baez microscope consisting of short focal length multilayer mirrors operating at an energy of 8 keV. In addition to realizing improvements in the resolution of the optics, the synchrotron radiation microscope is not limited to the usual single magnification at a fixed image plane. Higher magnification images are produced by projection in the limit of geometrical optics with a collimated beam. However, in distinction to the common method of placing the sample behind the optical source of a diverging beam, we describe the situation in which the sample is located in the collimated beam before the optical element. The ultimate limits of this magnification result from diffraction by the specimen and are determined by the sample position relative to the focal point of the optic. We present criteria by which the diffraction is minimized. PMID:27274930

X-ray spectral measurements for tungsten-anode from 20 to 49 kVp on a digital breast tomosynthesis system.

PubMed

Zhang, Da; Li, Xinhua; Liu, Bob

2012-06-01

This paper presents new spectral measurements of a tungsten-target digital breast tomosynthesis (DBT) system, including spectra of 43-49 kVp. Raw x-ray spectra of 20-49 kVp were directly measured from the tube port of a Selenia Dimensions DBT system using a CdTe based spectrometer. Two configurations of collimation were employed: one with two tungsten pinholes of 25 μm and 200 μm diameters, and the other with a single pinhole of 25 μm diameter, for acquiring spectra from the focal spot and from the focal spot as well as its vicinity. Stripping correction was applied to the measured spectra to compensate distortions due to escape events. The measured spectra were compared with the existing mammographic spectra of the TASMIP model in terms of photon fluence per exposure, spectral components, and half-value layer (HVL). HVLs were calculated from the spectra with a numerical filtration of 0.7 mm aluminum and were compared against actual measurements on the DBT system using W/Al (target-filter) combination, without paddle in the beam. The spectra from the double-pinhole configuration, in which the acceptance aperture pointed right at the focal spot, were harder than the single-pinhole spectra which include both primary and off-focus radiation. HVL calculated from the single-pinhole setup agreed with the measured HVL within 0.04 mm aluminum, while the HVL values from the double-pinhole setup were larger than the single-pinhole HVL by at most 0.1 mm aluminum. The spectra from single-pinhole setup agreed well with the TASMIP mammographic spectra, and are more relevant for clinical purpose. The spectra data would be useful for future research on DBT system with tungsten targets. © 2012 American Association of Physicists in Medicine.

Estimation of the laser cutting operating cost by support vector regression methodology

NASA Astrophysics Data System (ADS)

Jović, Srđan; Radović, Aleksandar; Šarkoćević, Živče; Petković, Dalibor; Alizamir, Meysam

2016-09-01

Laser cutting is a popular manufacturing process utilized to cut various types of materials economically. The operating cost is affected by laser power, cutting speed, assist gas pressure, nozzle diameter and focus point position as well as the workpiece material. In this article, the process factors investigated were: laser power, cutting speed, air pressure and focal point position. The aim of this work is to relate the operating cost to the process parameters mentioned above. CO2 laser cutting of stainless steel of medical grade AISI316L has been investigated. The main goal was to analyze the operating cost through the laser power, cutting speed, air pressure, focal point position and material thickness. Since the laser operating cost is a complex, non-linear task, soft computing optimization algorithms can be used. Intelligent soft computing scheme support vector regression (SVR) was implemented. The performance of the proposed estimator was confirmed with the simulation results. The SVR results are then compared with artificial neural network and genetic programing. According to the results, a greater improvement in estimation accuracy can be achieved through the SVR compared to other soft computing methodologies. The new optimization methods benefit from the soft computing capabilities of global optimization and multiobjective optimization rather than choosing a starting point by trial and error and combining multiple criteria into a single criterion.

The determination of complete human mitochondrial DNA sequences in single cells: implications for the study of somatic mitochondrial DNA point mutations

PubMed Central

Taylor, Robert W.; Taylor, Geoffrey A.; Durham, Steve E.; Turnbull, Douglass M.

2001-01-01

Studies of single cells have previously shown intracellular clonal expansion of mitochondrial DNA (mtDNA) mutations to levels that can cause a focal cytochrome c oxidase (COX) defect. Whilst techniques are available to study mtDNA rearrangements at the level of the single cell, recent interest has focused on the possible role of somatic mtDNA point mutations in ageing, neurodegenerative disease and cancer. We have therefore developed a method that permits the reliable determination of the entire mtDNA sequence from single cells without amplifying contaminating, nuclear-embedded pseudogenes. Sequencing and PCR–RFLP analyses of individual COX-negative muscle fibres from a patient with a previously described heteroplasmic COX II (T7587C) mutation indicate that mutant loads as low as 30% can be reliably detected by sequencing. This technique will be particularly useful in identifying the mtDNA mutational spectra in age-related COX-negative cells and will increase our understanding of the pathogenetic mechanisms by which they occur. PMID:11470889

Laser focus compensating sensing and imaging device

DOEpatents

Vann, Charles S.

1993-01-01

A laser focus compensating sensing and imaging device permits the focus of a single focal point of different frequency laser beams emanating from the same source point. In particular it allows the focusing of laser beam originating from the same laser device but having differing intensities so that a low intensity beam will not convert to a higher frequency when passing through a conversion crystal associated with the laser generating device. The laser focus compensating sensing and imaging device uses a cassegrain system to fold the lower frequency, low intensity beam back upon itself so that it will focus at the same focal point as a high intensity beam. An angular tilt compensating lens is mounted about the secondary mirror of the cassegrain system to assist in alignment. In addition cameras or CCD's are mounted with the primary mirror to sense the focused image. A convex lens is positioned co-axial with the cassegrain system on the side of the primary mirror distal of the secondary for use in aligning a target with the laser beam. A first alternate embodiment includes a cassegrain system using a series of shutters and an internally mounted dichroic mirror. A second alternate embodiment uses two laser focus compensating sensing and imaging devices for aligning a moving tool with a work piece.

Laser focus compensating sensing and imaging device

DOEpatents

Vann, C.S.

1993-08-31

A laser focus compensating sensing and imaging device permits the focus of a single focal point of different frequency laser beams emanating from the same source point. In particular it allows the focusing of laser beam originating from the same laser device but having differing intensities so that a low intensity beam will not convert to a higher frequency when passing through a conversion crystal associated with the laser generating device. The laser focus compensating sensing and imaging device uses a Cassegrain system to fold the lower frequency, low intensity beam back upon itself so that it will focus at the same focal point as a high intensity beam. An angular tilt compensating lens is mounted about the secondary mirror of the Cassegrain system to assist in alignment. In addition cameras or CCD's are mounted with the primary mirror to sense the focused image. A convex lens is positioned co-axial with the Cassegrain system on the side of the primary mirror distal of the secondary for use in aligning a target with the laser beam. A first alternate embodiment includes a Cassegrain system using a series of shutters and an internally mounted dichroic mirror. A second alternate embodiment uses two laser focus compensating sensing and imaging devices for aligning a moving tool with a work piece.

High Cost/High Risk Components to Chalcogenide Molded Lens Model: Molding Preforms and Mold Technology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bernacki, Bruce E.

2012-10-05

This brief report contains a critique of two key components of FiveFocal's cost model for glass compression molding of chalcogenide lenses for infrared applications. Molding preforms and mold technology have the greatest influence on the ultimate cost of the product and help determine the volumes needed to select glass molding over conventional single-point diamond turning or grinding and polishing. This brief report highlights key areas of both technologies with recommendations for further study.

Point Relay Scanner Utilizing Ellipsoidal Mirrors

NASA Technical Reports Server (NTRS)

Manhart, Paul K. (Inventor); Pagano, Robert J. (Inventor)

1997-01-01

A scanning system uses a polygonal mirror assembly with each facet of the polygon having an ellipsoidal mirror located thereon. One focal point of each ellipsoidal mirror is located at a common point on the axis of rotation of the polygonal mirror assembly. As the mirror assembly rotates. a second focal point of the ellipsoidal mirrors traces out a scan line. The scanner can be utilized for scanned output display of information or for scanning information to be detected.

Lydia Finney appointed WIST program initiator - Argonne Today

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Home Mission People Work/Life Connections Focal Point Inside Argonne Argonne Public Website Argonne Today Argonne Today Mission People Work/Life Connections Focal Point Lydia Finney appointed WIST program initiator Home People Lydia Finney appointed WIST program initiator Lydia Finney appointed WIST

Continuously variable focal length lens

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adams, Bernhard W; Chollet, Matthieu C

2013-12-17

A material preferably in crystal form having a low atomic number such as beryllium (Z=4) provides for the focusing of x-rays in a continuously variable manner. The material is provided with plural spaced curvilinear, optically matched slots and/or recesses through which an x-ray beam is directed. The focal length of the material may be decreased or increased by increasing or decreasing, respectively, the number of slots (or recesses) through which the x-ray beam is directed, while fine tuning of the focal length is accomplished by rotation of the material so as to change the path length of the x-ray beammore » through the aligned cylindrical slows. X-ray analysis of a fixed point in a solid material may be performed by scanning the energy of the x-ray beam while rotating the material to maintain the beam's focal point at a fixed point in the specimen undergoing analysis.« less

Physical Activity Performance of Focal Middle School Students

ERIC Educational Resources Information Center

Erfle, Stephen E.; Gelbaugh, Corey M.

2013-01-01

Histograms of push-ups and curl-ups from a sample of more than 9,000 students show periodic spikes at five and 10 unit intervals. This article argues that these spikes are related to focal points, a game theoretic concept popularized by Nobel Laureate Thomas Schelling. Being focal on one test makes one more likely to be focal on the other. Focal…

Research on adaptive temperature control in sound field induced by self-focused concave spherical transducer.

PubMed

Hu, Jiwen; Qian, Shengyou; Ding, Yajun

2010-05-01

Temperature control of hyperthermia treatments is generally implemented with multipoint feedback system comprised of phased-array transducer, which is complicated and high cost. Our simulations to the acoustic field induced by a self-focused concave spherical transducer (0.5MHz, 9cm aperture width, 8.0cm focal length) show that the distribution of temperature can keep the same "cigar shape" in the focal region during ultrasound insonation. Based on the characteristic of the temperature change, a two-dimensional model of a "cigar shape" tumor is designed and tested through numerical simulation. One single-point on the border of the "cigar shape" tumor is selected as the control target and is controlled at the temperature of 43 degrees C by using a self-tuning regulator (STR). Considering the nonlinear effects of biological medium, an accurate state-space model obtained via the finite Fourier integral transformation to the bioheat equation is presented and used for calculating temperature. Computer simulations were performed with the perfusion rates of 2.0kg/(m(3)s) and 4.5kg/(m(3)s) to the different targets, it was found that the temperatures on the border of the "cigar shape" tumor can achieve the desired temperature of 43 degrees C by control of one single-point. A larger perfusion rate requires a higher power output to obtain the same temperature elevation under the same insonation time and needs a higher cost for compensating the energy loss carried away by blood flow after steady state. The power output increases with the controlled region while achieving the same temperature at the same time. Especially, there is no overshoot during temperature elevation and no oscillation after steady state. The simulation results demonstrate that the proposed approach may offers a way for obtaining a single-point, low-cost hyperthermia system. Copyright 2010 Elsevier B.V. All rights reserved.

Variation of canine vertebral bone architecture in computed tomography

PubMed Central

Cheon, Byunggyu; Park, Seungjo; Lee, Sang-kwon; Park, Jun-Gyu; Cho, Kyoung-Oh

2018-01-01

Focal vertebral bone density changes were assessed in vertebral computed tomography (CT) images obtained from clinically healthy dogs without diseases that affect bone density. The number, location, and density of lesions were determined. A total of 429 vertebral CT images from 20 dogs were reviewed, and 99 focal vertebral changes were identified in 14 dogs. Focal vertebral bone density changes were mainly found in thoracic vertebrae (29.6%) as hyperattenuating (86.9%) lesions. All focal vertebral changes were observed at the vertebral body, except for a single hyperattenuating change in one thoracic transverse process. Among the hyperattenuating changes, multifocal changes (53.5%) were more common than single changes (46.5%). Most of the hypoattenuating changes were single (92.3%). Eight dogs, 40% of the 20 dogs in the study and 61.6% of the 13 dogs showing focal vertebral changes in the thoracic vertebra, had hyperattenuating changes at the 7th or 8th thoracic vertebra. Our results indicate that focal changes in vertebral bone density are commonly identified on vertebral CT images in healthy dogs, and these changes should be taken into consideration on interpretation of CT images. PMID:28693309

Focal points and principal solutions of linear Hamiltonian systems revisited

NASA Astrophysics Data System (ADS)

Šepitka, Peter; Šimon Hilscher, Roman

2018-05-01

In this paper we present a novel view on the principal (and antiprincipal) solutions of linear Hamiltonian systems, as well as on the focal points of their conjoined bases. We present a new and unified theory of principal (and antiprincipal) solutions at a finite point and at infinity, and apply it to obtain new representation of the multiplicities of right and left proper focal points of conjoined bases. We show that these multiplicities can be characterized by the abnormality of the system in a neighborhood of the given point and by the rank of the associated T-matrix from the theory of principal (and antiprincipal) solutions. We also derive some additional important results concerning the representation of T-matrices and associated normalized conjoined bases. The results in this paper are new even for completely controllable linear Hamiltonian systems. We also discuss other potential applications of our main results, in particular in the singular Sturmian theory.

Noncontact Tactile Display Based on Radiation Pressure of Airborne Ultrasound.

PubMed

Hoshi, T; Takahashi, M; Iwamoto, T; Shinoda, H

2010-01-01

This paper describes a tactile display which provides unrestricted tactile feedback in air without any mechanical contact. It controls ultrasound and produces a stress field in a 3D space. The principle is based on a nonlinear phenomenon of ultrasound: Acoustic radiation pressure. The fabricated prototype consists of 324 airborne ultrasound transducers, and the phase and intensity of each transducer are controlled individually to generate a focal point. The DC output force at the focal point is 16 mN and the diameter of the focal point is 20 mm. The prototype produces vibrations up to 1 kHz. An interaction system including the prototype is also introduced, which enables users to see and touch virtual objects.

Focal Points, Endogenous Processes, and Exogenous Shocks in the Autism Epidemic

ERIC Educational Resources Information Center

Liu, Kayuet; Bearman, Peter S.

2015-01-01

Autism prevalence has increased rapidly in the United States during the past two decades. We have previously shown that the diffusion of information about autism through spatially proximate social relations has contributed significantly to the epidemic. This study expands on this finding by identifying the focal points for interaction that drive…

Women in Energy: Rinku Gupta - Argonne Today

Science.gov Websites

Home Mission People Work/Life Connections Focal Point Inside Argonne Argonne Public Website Argonne Today Argonne Today Mission People Work/Life Connections Focal Point Women in Energy: Rinku Gupta Home People Women in Energy: Rinku Gupta Women in Energy: Rinku Gupta Apr 1, 2016 | Posted by Argonne

Measles elimination – review of event notifications sent to National IHR Focal Point between 2010 and 2016

PubMed

Izdebski, Radosław; Henszel, Łukasz; Janiec, Janusz; Radziszewski, Franciszek

The Member States of the World Health Organization (WHO) in accordance with International Health Regulations (2005) were obliged to appoint National IHR Focal Points (N IHR FP), of which tasks include obtaining information concerning public health emergencies of international concern which occurred abroad or within the country. The aim of this work is the review of WHO, ECDC, National IHR Focal Points from the WHO Member States and The State Sanitary Inspection notifications related to measles received by National IHR Focal Point in Poland in the period from 2010 to 2016. During this period N IHR FP was informed about 79 events related to measles. These events include: 36 related to the outbreaks in different countries, 27 concerning individual cases, 14 related to the exposure in contact with a measles case during air travel and two concerning the implementation of the MMR vaccination programs. Despite the progress in implementing the measures included in the elimination of measles programs in Europe, there was a significant increase in the number of measles cases and outbreaks particularly in years 2010-2011.

Statistical Earthquake Focal Mechanism Forecasts

NASA Astrophysics Data System (ADS)

Kagan, Y. Y.; Jackson, D. D.

2013-12-01

The new whole Earth focal mechanism forecast, based on the GCMT catalog, has been created. In the present forecast, the sum of normalized seismic moment tensors within 1000 km radius is calculated and the P- and T-axes for the focal mechanism are evaluated on the basis of the sum. Simultaneously we calculate an average rotation angle between the forecasted mechanism and all the surrounding mechanisms. This average angle shows tectonic complexity of a region and indicates the accuracy of the prediction. The method was originally proposed by Kagan and Jackson (1994, JGR). Recent interest by CSEP and GEM has motivated some improvements, particularly to extend the previous forecast to polar and near-polar regions. The major problem in extending the forecast is the focal mechanism calculation on a spherical surface. In the previous forecast as our average focal mechanism was computed, it was assumed that longitude lines are approximately parallel within 1000 km radius. This is largely accurate in the equatorial and near-equatorial areas. However, when one approaches the 75 degree latitude, the longitude lines are no longer parallel: the bearing (azimuthal) difference at points separated by 1000 km reach about 35 degrees. In most situations a forecast point where we calculate an average focal mechanism is surrounded by earthquakes, so a bias should not be strong due to the difference effect cancellation. But if we move into polar regions, the bearing difference could approach 180 degrees. In a modified program focal mechanisms have been projected on a plane tangent to a sphere at a forecast point. New longitude axes which are parallel in the tangent plane are corrected for the bearing difference. A comparison with the old 75S-75N forecast shows that in equatorial regions the forecasted focal mechanisms are almost the same, and the difference in the forecasted focal mechanisms rotation angle is close to zero. However, though the forecasted focal mechanisms are similar, closer to the 75 latitude degree, the difference in the rotation angle is large (around a factor 1.5 in some places). The Gamma-index was calculated for the average focal mechanism moment. A non-zero Index indicates that earthquake focal mechanisms around the forecast point have different orientations. Thus deformation complexity displays itself in the average rotation angle and in the Index. However, sometimes the rotation angle is close to zero, whereas the Index is large, testifying to a large CLVD presence. Both new 0.5x0.5 and 0.1x0.1 degree forecasts are posted at http://eq.ess.ucla.edu/~kagan/glob_gcmt_index.html.

Thin plastic foil X-ray optics with spiral geometry

NASA Astrophysics Data System (ADS)

Barbera, Marco; Mineo, Teresa; Perinati, Emanuele; Schnopper, Herbert W.; Taibi, Angelo

2007-09-01

Winding a plastic foil ribbon into spiral cylinder or spiral cones we can design and build single or multiple reflection X-ray grazing incidence focusing optics with potential applications in Astronomy as well as experimental physics. The use of thin plastic foils from common industrial applications and of a mounting technique which does not require the construction of mandrels make these optics very cost effective. A spiral geometry focusing optic produces an annular image of a point source with the angular size of the annulus depending mainly on the pitch of the winding and the focal length. We use a ray-tracing code to evaluate the performances of cylindrical, and double conical spiral geometry as a function of the design parameters e.g. focal length, diameter, optic length. Some preliminary results are presented on X-ray imaging tests performed on spiral cylindrical optics.

Testing of focal plane arrays at the AEDC

NASA Astrophysics Data System (ADS)

Nicholson, Randy A.; Mead, Kimberly D.; Smith, Robert W.

1992-07-01

A facility was developed at the Arnold Engineering Development Center (AEDC) to provide complete radiometric characterization of focal plane arrays (FPAs). The highly versatile facility provides the capability to test single detectors, detector arrays, and hybrid FPAs. The primary component of the AEDC test facility is the Focal Plane Characterization Chamber (FPCC). The FPCC provides a cryogenic, low-background environment for the test focal plane. Focal plane testing in the FPCC includes flood source testing, during which the array is uniformly irradiated with IR radiation, and spot source testing, during which the target radiation is focused onto a single pixel or group of pixels. During flood source testing, performance parameters such as power consumption, responsivity, noise equivalent input, dynamic range, radiometric stability, recovery time, and array uniformity can be assessed. Crosstalk is evaluated during spot source testing. Spectral response testing is performed in a spectral response test station using a three-grating monochromator. Because the chamber can accommodate several types of testing in a single test installation, a high throughput rate and good economy of operation are possible.

Infrared Smartt Interferometer As An Alignment Tool For Carbon Dioxide Laser Fusion Systems

NASA Astrophysics Data System (ADS)

Viswanathan, V. K.; Bolen, P. D.

1980-11-01

It is essential to minimize the pointing and focusing errors at the focal plane for many applications involving infrared laser systems. In the case of the LASL CO2 laser fusion systems, with two beams in the Gemini System and eight beams in the Helios System, this is particularly important. The LASL Helios CO2 Laser Fusion System has eight 34-cm diameter beams emerging from the power amplifier and each beam is brought to focus by an off-aperture parabola (nearly 77.3-cm focal length) resulting in a nearly F/2.4 beam at the focal plane. The design tolerance at the focal plane for pointing accuracy is +/- 25 microns and for focusing accuracy is +/- 50 microns for this system. This paper describes an alignment scheme based on the use of the infrared Smartt interferometer' and compares the results obtained using this technique and the autocollimating Hartmann scheme2 in a laboratory setup duplicating the target chamber region of one of the beams of the Helios System. The results using the Smartt interferometer show that pointing accuracy of +/- 12.5 microns and focusing accuracies of ± 15 microns are obtained at the focal plane of the system.

Laser head for simultaneous optical pumping of several dye lasers. [with single flash lamp

NASA Technical Reports Server (NTRS)

Mumola, P. B.; Mcalexander, B. T. (Inventor)

1975-01-01

The invention is a laser head for simultaneous pumping several dye lasers with a single flash lamp. The laser head includes primarily a multi-elliptical cylinder cavity with a single flash lamp placed along the common focal axis of the cavity and with capillary tube dye cells placed along each of the other focal axes of the cavity. The inside surface of the cavity is polished. Hence, the single flash lamp supplies the energy to the several dye cells.

Charge integration successive approximation analog-to-digital converter for focal plane applications using a single amplifier

NASA Technical Reports Server (NTRS)

Zhou, Zhimin (Inventor); Pain, Bedabrata (Inventor)

1999-01-01

An analog-to-digital converter for on-chip focal-plane image sensor applications. The analog-to-digital converter utilizes a single charge integrating amplifier in a charge balancing architecture to implement successive approximation analog-to-digital conversion. This design requires minimal chip area and has high speed and low power dissipation for operation in the 2-10 bit range. The invention is particularly well suited to CMOS on-chip applications requiring many analog-to-digital converters, such as column-parallel focal-plane architectures.

Modeling of Pixelated Detector in SPECT Pinhole Reconstruction.

PubMed

Feng, Bing; Zeng, Gengsheng L

2014-04-10

A challenge for the pixelated detector is that the detector response of a gamma-ray photon varies with the incident angle and the incident location within a crystal. The normalization map obtained by measuring the flood of a point-source at a large distance can lead to artifacts in reconstructed images. In this work, we investigated a method of generating normalization maps by ray-tracing through the pixelated detector based on the imaging geometry and the photo-peak energy for the specific isotope. The normalization is defined for each pinhole as the normalized detector response for a point-source placed at the focal point of the pinhole. Ray-tracing is used to generate the ideal flood image for a point-source. Each crystal pitch area on the back of the detector is divided into 60 × 60 sub-pixels. Lines are obtained by connecting between a point-source and the centers of sub-pixels inside each crystal pitch area. For each line ray-tracing starts from the entrance point at the detector face and ends at the center of a sub-pixel on the back of the detector. Only the attenuation by NaI(Tl) crystals along each ray is assumed to contribute directly to the flood image. The attenuation by the silica (SiO 2 ) reflector is also included in the ray-tracing. To calculate the normalization for a pinhole, we need to calculate the ideal flood for a point-source at 360 mm distance (where the point-source was placed for the regular flood measurement) and the ideal flood image for the point-source at the pinhole focal point, together with the flood measurement at 360 mm distance. The normalizations are incorporated in the iterative OSEM reconstruction as a component of the projection matrix. Applications to single-pinhole and multi-pinhole imaging showed that this method greatly reduced the reconstruction artifacts.

The positive impact of simultaneous implementation of the BD FocalPoint GS Imaging System and lean principles on the operation of gynecologic cytology.

PubMed

Wong, Rebecca; Levi, Angelique W; Harigopal, Malini; Schofield, Kevin; Chhieng, David C

2012-02-01

Our cytology laboratory, like many others, is under pressure to improve quality and provide test results faster while decreasing costs. We sought to address these issues by introducing new technology and lean principles. To determine the combined impact of the FocalPoint Guided Screener (GS) Imaging System (BD Diagnostics-TriPath, Burlington, North Carolina) and lean manufacturing principles on the turnaround time (TAT) and productivity of the gynecologic cytology operation. We established a baseline measure of the TAT for Papanicolaou tests. We then compared that to the performance after implementing the FocalPoint GS Imaging System and lean principles. The latter included value-stream mapping, workflow modification, and a first in-first out policy. The mean (SD) TAT for Papanicolaou tests before and after the implementation of FocalPoint GS Imaging System and lean principles was 4.38 (1.28) days and 3.20 (1.32) days, respectively. This represented a 27% improvement in the average TAT, which was statistically significant (P < .001). In addition, the productivity of staff improved 17%, as evidenced by the increase in slides screened from 8.85/h to 10.38/h. The false-negative fraction decreased from 1.4% to 0.9%, representing a 36% improvement. In our laboratory, the implementation of FocalPoint GS Imaging System in conjunction with lean principles resulted in a significant decrease in the average TAT for Papanicolaou tests and a substantial increase in the productivity of cytotechnologists while maintaining the diagnostic quality of gynecologic cytology.

Picture archiving and computing systems: the key to enterprise digital imaging.

PubMed

Krohn, Richard

2002-09-01

The utopian view of the electronic medical record includes the digital transformation of all aspects of patient information. Historically, imagery from the radiology, cardiology, ophthalmology, and pathology departments, as well as the emergency room, has been a morass of paper, film, and other media, isolated within each department's system architecture. In answer to this dilemma, picture archiving and computing systems have become the focal point of efforts to create a single platform for the collection, storage, and distribution of clinical imagery throughout the health care enterprise.

To Fight or Not to Fight? Organizational and Doctrinal Trends in Mounted Maneuver Reconnaissance from the Interwar Years to Operation Iraqi Freedom

DTIC Science & Technology

2010-01-01

cavalry trainer developed to improve the preparation of cavalry leaders through the integrated use of radios and movie projectors—the forerunner of...ies of water without special equipment. In the support squad, two jeeps and a trailer carried an 81-mm mortar, its crew, and ammunition.83 These...them with a single 81-mm mortar. This weapon constituted the focal point of the support squad, which included two jeeps and two trailers . The latter

Partnering with Families. Focal Point: A National Bulletin on Family Support and Children's Mental Health. Volume 18, Number 1, Summer 2004

ERIC Educational Resources Information Center

Walker, Janet S., Ed.

2004-01-01

The articles in this issue of "Focal Point" focus on the Research and Training Center's current work, which reflects the evolution of expectations for partnering with youth and families. Partnering successfully requires not only a philosophical commitment to the value, but also intentional, specific steps to redesign services and reallocate…

Emerging infectious diseases not covered by routine vaccination in Europe in 2010-2015--the review of WHO and ECDC notifications for the National IHR Focal Point in Poland.

PubMed

Henszel, Łukasz; Janiec, Janusz; Izdebski, Radosław; Radziszewski, Franciszek; Polański, Piotr

2015-01-01

The National IHR Focal Point is a center set up by each Member State of the World Health Organization (WHO) in accordance with the International Health Regulations (2005). The International Health Regulations (IHR) were adopted on 23 May 2005 at the World Health Assembly and entered into force since 15 June 2007 as the legal instrument designed to help protect all countries from uncontrolled international spread of diseases and other urgent public health threats. According to Article 2 of IHR the purpose and scope of these Regulations are to prevent, protect against, control and provide a public health response to the international spread of disease in ways that are commensurate with and restricted to public health risks, and which avoid unnecessary interference with international traffic and trade. Primarily, the scope of IHR is to establish a system of early warning (in accordance with Article 6 and 7) with the functioning in each country National IHR Focal Point which is available at any time to communicate with WHO IHR Contact Points and other entities. The tasks of the National IHR Fo- cal Point in Poland which was appointed by the Minister of Health and runs in the Department of Epidemiology, National Institute of Public Health--National Institute of Hygiene from 1 September 2007 are the notification of events that may constitute a public health emergency of international concern occurring in Poland or abroad and the dissemination of this information to the WHO, other National IHR Focal Points or competent authorities responsible for public health. The task of the National IHR Focal Point in Poland is also the dissemination of WHO and ECDC notifications, including recommendation and risk assessment documents. The aim of this work is the review of WHO and ECDC notifications received by National IHR Focal Point in Poland in the period from 2010 to 2015 which were related to emerging infectious diseases not covered by routine vaccination programs or for which there are no effective vaccines that have occurred in the WHO European Region. The review includes verotoxin-producing Escherichia coli O104: H4 infections, MERS-CoV infections, Ebola virus disease, malaria, dengue fever, West Nile fever, chikungunya and cholera.

A new measurement method of profile tolerance for the LAMOST focal plane

NASA Astrophysics Data System (ADS)

Zhou, Zengxiang; Jin, Yi; Zhai, Chao; Xing, Xiaozheng

2008-07-01

There were a few methods taken in the profile tolerance measurement of the LAMOST Focal Plane Plate. One of the methods was to use CMM (Coordinate Measurement Machine) to measure the points on the small Focal Plane Plate and calculate the points whether or not in the tolerance zone. In this process there are some small shortcomings. The measuring point positions on the Focal Plane Plate are not the actual installation location of the optical fiber positioning system. In order to eliminate these principle errors, a measuring mandrel is inserted into the unit-holes, and the precision for the mandrel with the hole is controlled in the high level. Then measure the center of the precise target ball which is placed on the measuring mandrel by CMM. At last, fit a sphere surface with the measuring center points of the target ball and analyze the profile tolerance of the Focal Plane Plate. This process will be more in line with the actual installation location of the optical fiber positioning system. When use this method to judge the profile tolerance can provide the reference date for maintaining the ultra error unit-holes on the Focal Plane Plate. But when insert the measuring mandrel into the unit hole, there are manufacturing errors in the measuring mandrel, target ball and assembly errors. All these errors will bring the influence in the measurement. In the paper, an impact evaluation assesses the intermediate process with all these errors through experiments. And the experiment results show that there are little influence when use the target ball and the measuring mandrel in the measurement of the profile tolerance. Instead, there are more advantages than many past use of measuring methods.

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

PubMed

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

2016-04-01

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

Per-Pixel, Dual-Counter Scheme for Optical Communications

NASA Technical Reports Server (NTRS)

Farr, William H.; Bimbaum, Kevin M.; Quirk, Kevin J.; Sburlan, Suzana; Sahasrabudhe, Adit

2013-01-01

Free space optical communications links from deep space are projected to fulfill future NASA communication requirements for 2020 and beyond. Accurate laser-beam pointing is required to achieve high data rates at low power levels.This innovation is a per-pixel processing scheme using a pair of three-state digital counters to implement acquisition and tracking of a dim laser beacon transmitted from Earth for pointing control of an interplanetary optical communications system using a focal plane array of single sensitive detectors. It shows how to implement dim beacon acquisition and tracking for an interplanetary optical transceiver with a method that is suitable for both achieving theoretical performance, as well as supporting additional functions of high data rate forward links and precision spacecraft ranging.

Single-photon-multi-layer-interference lithography for high-aspect-ratio and three-dimensional SU-8 micro-/nanostructures.

PubMed

Ghosh, Siddharth; Ananthasuresh, G K

2016-01-04

We report microstructures of SU-8 photo-sensitive polymer with high-aspect-ratio, which is defined as the ratio of height to in-plane feature size. The highest aspect ratio achieved in this work exceeds 250. A multi-layer and single-photon lithography approach is used in this work to expose SU-8 photoresist of thickness up to 100 μm. Here, multi-layer and time-lapsed writing is the key concept that enables nanometer localised controlled photo-induced polymerisation. We use a converging monochromatic laser beam of 405 nm wavelength with a controllable aperture. The reflection of the converging optics from the silicon substrate underneath is responsible for a trapezoidal edge profile of SU-8 microstructure. The reflection induced interfered point-spread-function and multi-layer-single-photon exposure helps to achieve sub-wavelength feature sizes. We obtained a 75 nm tip diameter on a pyramid shaped microstructure. The converging beam profile determines the number of multiple optical focal planes along the depth of field. These focal planes are scanned and exposed non-concurrently with varying energy dosage. It is notable that an un-automated height axis control is sufficient for this method. All of these contribute to realising super-high-aspect-ratio and 3D micro-/nanostructures using SU-8. Finally, we also address the critical problems of photoresist-based micro-/nanofabrication and their solutions.

Corrections. Focal Point: Research, Policy, and Practice in Children's Mental Health. Volume 20, Number 2, Summer 2006

ERIC Educational Resources Information Center

Walker, Janet S., Ed.

2006-01-01

This issue of "Focal Point" describes the need for, and provides examples of, new strategies for meeting the mental health needs of children and adolescents involved with the juvenile justice system. Articles in this issue discuss the particular need for correction in the way that the juvenile justice system interacts with youth who have mental…

Workforce. Focal Point: Research, Policy, and Practice in Children's Mental Health. Volume 22, Number 1, Winter 2008

ERIC Educational Resources Information Center

Walker, Janet S., Ed.; Gowen, L. Kris, Ed.; Aue, Nicole, Ed.

2008-01-01

This issue of "Focal Point" explores how the increasing emphasis on using evidence-based practices and a "system of care" approach is driving changes in jobs and roles related to children's mental health. Articles in the issue describe how agencies and providers of services and supports have responded to these changes by creating new types of…

Resilience and Recovery. Focal Point: Research, Policy, and Practice in Children's Mental Health. Volume 19, Number 1, Summer 2005

ERIC Educational Resources Information Center

Walker, Janet S., Ed.

2005-01-01

This issue of "Focal Point" explores the concepts of resilience and recovery and what they mean in the context of mental health care for children and adolescents. From the articles, it emerges that the terminology associated with recovery and resilience (particularly the word, recovery, itself) can be confusing and even off-putting to…

Strengthening Social Support. Focal Point: Research, Policy, and Practice in Children's Mental Health. Volume 20, Number 1, Winter 2006

ERIC Educational Resources Information Center

Walker, Janet S., Ed.

2006-01-01

This issue of "Focal Point" explores some of what is known and unknown about strengthening social support. This introduction outlines some of the major concepts and themes in research on social support, and some implications of this research for interventions in children's mental health. This sets the stage for the rest of the issue, which…

Tests of the Monte Carlo simulation of the photon-tagger focal-plane electronics at the MAX IV Laboratory

NASA Astrophysics Data System (ADS)

Preston, M. F.; Myers, L. S.; Annand, J. R. M.; Fissum, K. G.; Hansen, K.; Isaksson, L.; Jebali, R.; Lundin, M.

2014-04-01

Rate-dependent effects in the electronics used to instrument the tagger focal plane at the MAX IV Laboratory were recently investigated using the novel approach of Monte Carlo simulation to allow for normalization of high-rate experimental data acquired with single-hit time-to-digital converters (TDCs). The instrumentation of the tagger focal plane has now been expanded to include multi-hit TDCs. The agreement between results obtained from data taken using single-hit and multi-hit TDCs demonstrate a thorough understanding of the behavior of the detector system.

Single-session endoscopic resection and focal radiofrequency ablation for short-segment Barrett's esophagus with early neoplasia.

PubMed

Barret, Maximilien; Belghazi, Kamar; Weusten, Bas L A M; Bergman, Jacques J G H M; Pouw, Roos E

2016-07-01

The management of early neoplasia in Barrett's esophagus (BE) requires endoscopic resection of visible lesions, followed by radiofrequency ablation (RFA) of the remaining BE. We evaluated the safety and efficacy of combining endoscopic resection and focal RFA in a single endoscopic session in patients with early BE neoplasia. This was a retrospective analysis of patients with early BE neoplasia and a visible lesion undergoing combined endoscopic resection and focal RFA in a single session. Consecutive ablation procedures were performed every 8 to 12 weeks until complete endoscopic and histologic eradication of dysplasia and intestinal metaplasia were reached. Forty patients were enrolled, with a median C1M2 BE segment, a visible lesion with a median diameter of 15 mm, and invasive carcinoma in 68% of cases. Endoscopic resection was performed by using the multiband mucosectomy technique in 80% of cases, and the Barrx(90) catheter (Barrx Medical, Sunnyvale, Calif) was used for focal ablation. When an intention-to-treat analysis was used, both complete remission of all neoplasia and intestinal metaplasia were 95% after a median follow-up of 19 months. Stenoses occurred in 33% of cases and were successfully managed with a median number of 2 dilations. In 43% of patients, 1 single-session treatment resulted in complete histologic remission of intestinal metaplasia. Combining endoscopic resection and focal RFA in a single session appears to be effective. Less-aggressive RFA regimens could limit the adverse event rates. Copyright © 2016 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

DCEUS-based focal parametric perfusion imaging of microvessel with single-pixel resolution and high contrast.

PubMed

Wang, Diya; Xiao, Mengnan; Hu, Hong; Zhang, Yu; Su, Zhe; Xu, Shanshan; Zong, Yujin; Wan, Mingxi

2018-03-01

This study aimed to develop a focal microvascular contrast-enhanced ultrasonic parametric perfusion imaging (PPI) scheme to overcome the tradeoff between the resolution, contrast, and accuracy of focal PPI in the tumor. Its resolution was limited by the low signal-to-clutter ratio (SCR) of time-intensity-curves (TICs) induced by multiple limitations, which deteriorated the accuracy and contrast of focal PPI. The scheme was verified by the in-vivo perfusion experiments. Single-pixel TICs were first extracted to ensure PPI with the highest resolution. The SCR of focal TICs in the tumor was improved using respiratory motion compensation combined with detrended fluctuation analysis. The entire and focal PPIs of six perfusion parameters were then accurately created after filtrating the valid TICs and targeted perfusion parameters. Compared with those of the conventional PPIs, the axial and lateral resolutions of focal PPIs were improved by 30.29% (p < .05) and 32.77% (p < .05), respectively; the average contrast and accuracy evaluated by SCR improved by 7.24 ± 4.90 dB (p < .05) and 5.18 ± 1.28 dB (p < .05), respectively. The edge, morphostructure, inhomogeneous hyper-enhanced distribution, and ring-like perfusion features in intratumoral microvessel were accurately distinguished and highlighted by the focal PPIs. The developed focal PPI can assist clinicians in making confirmed diagnoses and in providing appropriate therapeutic strategies for liver tumor. Copyright © 2017 Elsevier B.V. All rights reserved.

Formation of the Light Infantry.

DTIC Science & Technology

1986-03-21

for light infantry force. Using the conversion of the Army’s 7th Infantry Division as the focal point, the critical issues that effected that...7th Infantry Division-as the focal point, the critical issues that effected that conversion are discussed. Personnel issues addressed consider the...Fort Ord one day and leaving for Fort Benning the next were not uncommon. This slow formation also impacted on the effectiveness of the initial

Focal Point Inside the Vacuum Chamber for Solar Thermal Propulsion

NASA Technical Reports Server (NTRS)

1999-01-01

Researchers at the Marshall Space Flight Center (MSFC) have designed, fabricated, and tested the first solar thermal engine, a non-chemical rocket engine that produces lower thrust but has better thrust efficiency than a chemical combustion engine. MSFC turned to solar thermal propulsion in the early 1990s due to its simplicity, safety, low cost, and commonality with other propulsion systems. Solar thermal propulsion works by acquiring and redirecting solar energy to heat a propellant. The 20- by 24-ft heliostat mirror (not shown in this photograph) has dual-axis control that keeps a reflection of the sunlight on an 18-ft diameter concentrator mirror, which then focuses the sunlight to a 4-in focal point inside the vacuum chamber. The focal point has 10 kilowatts of intense solar power. This photograph is a close-up view of a 4-in focal point inside the vacuum chamber at the MSFC Solar Thermal Propulsion Test facility. As part of MSFC's Space Transportation Directorate, the Propulsion Research Center serves as a national resource for research of advanced, revolutionary propulsion technologies. The mission is to move the Nation's capabilities beyond the confines of conventional chemical propulsion into an era of aircraft-like access to Earth orbit, rapid travel throughout the solar system, and exploration of interstellar space.

Aberration-free aspherical lens shape for shortening the focal distance of an already convergent beam

PubMed Central

Sutter, John P.; Alianelli, Lucia

2017-01-01

The shapes of single lens surfaces capable of focusing divergent and collimated beams without aberration have already been calculated. However, nanofocusing compound refractive lenses (CRLs) require many consecutive lens surfaces. Here a theoretical example of an X-ray nanofocusing CRL with 48 consecutive surfaces is studied. The surfaces on the downstream end of this CRL accept X-rays that are already converging toward a focus, and refract them toward a new focal point that is closer to the surface. This case, so far missing from the literature, is treated here. The ideal surface for aberration-free focusing of a convergent incident beam is found by analytical computation and by ray tracing to be one sheet of a Cartesian oval. An ‘X-ray approximation’ of the Cartesian oval is worked out for the case of small change in index of refraction across the lens surface. The paraxial approximation of this surface is described. These results will assist the development of large-aperture CRLs for nanofocusing. PMID:29091055

Single-lens computed tomography imaging spectrometer and method of capturing spatial and spectral information

NASA Technical Reports Server (NTRS)

Wilson, Daniel W. (Inventor); Johnson, William R. (Inventor); Bearman, Gregory H. (Inventor)

2011-01-01

Computed tomography imaging spectrometers ("CTISs") employing a single lens are provided. The CTISs may be either transmissive or reflective, and the single lens is either configured to transmit and receive uncollimated light (in transmissive systems), or is configured to reflect and receive uncollimated light (in reflective systems). An exemplary transmissive CTIS includes a focal plane array detector, a single lens configured to transmit and receive uncollimated light, a two-dimensional grating, and a field stop aperture. An exemplary reflective CTIS includes a focal plane array detector, a single mirror configured to reflect and receive uncollimated light, a two-dimensional grating, and a field stop aperture.

Reflectance calibration of focal plane array hyperspectral imaging system for agricultural and food safety applications

NASA Astrophysics Data System (ADS)

Lawrence, Kurt C.; Park, Bosoon; Windham, William R.; Mao, Chengye; Poole, Gavin H.

2003-03-01

A method to calibrate a pushbroom hyperspectral imaging system for "near-field" applications in agricultural and food safety has been demonstrated. The method consists of a modified geometric control point correction applied to a focal plane array to remove smile and keystone distortion from the system. Once a FPA correction was applied, single wavelength and distance calibrations were used to describe all points on the FPA. Finally, a percent reflectance calibration, applied on a pixel-by-pixel basis, was used for accurate measurements for the hyperspectral imaging system. The method was demonstrated with a stationary prism-grating-prism, pushbroom hyperspectral imaging system. For the system described, wavelength and distance calibrations were used to reduce the wavelength errors to <0.5 nm and distance errors to <0.01mm (across the entrance slit width). The pixel-by-pixel percent reflectance calibration, which was performed at all wavelengths with dark current and 99% reflectance calibration-panel measurements, was verified with measurements on a certified gradient Spectralon panel with values ranging from about 14% reflectance to 99% reflectance with errors generally less than 5% at the mid-wavelength measurements. Results from the calibration method, indicate the hyperspectral imaging system has a usable range between 420 nm and 840 nm. Outside this range, errors increase significantly.

Three-dimensional characterization of tightly focused fields for various polarization incident beams

NASA Astrophysics Data System (ADS)

Cai, Yanan; Liang, Yansheng; Lei, Ming; Yan, Shaohui; Wang, Zhaojun; Yu, Xianghua; Li, Manman; Dan, Dan; Qian, Jia; Yao, Baoli

2017-06-01

Tightly focused vectorial optical beams have found extensive applications in variety of technical fields like single-molecule detection, optical tweezers, and super-resolution optical microscopy. Such applications require an accurate measurement and manipulation of focal optical fields. We have developed a compact instrument (with dimensions of 35 × 35 × 30 cm3) to rapidly measure the intensity distribution in three dimensions of the focused fields of vectorial beams and any other incident beams. This instrument employs a fluorescent nanoparticle as a probe to scan the focal region to obtain a high spatial resolution of intensity distribution. It integrates a liquid-crystal spatial light modulator to allow for tailoring the point spread function of the optical system, making it a useful tool for multi-purpose and flexible research. The robust applicability of the instrument is verified by measuring the 3D intensity distributions of focal fields of various polarization and wavefront modulated incident beams focused by a high NA (=1.25) objective lens. The minimal data acquisition time achievable in the experiment is about 8 s for a scanning region of 3.2 × 3.2 μm2 (512 × 512 pixels). The measured results are in good agreement with those predicted by the vectorial diffraction theory.

Ferroelectric or non-ferroelectric: Why so many materials exhibit “ferroelectricity” on the nanoscale

DOE PAGES

Vasudevan, Rama K.; Balke, Nina; Maksymovych, Peter; ...

2017-05-01

Here, ferroelectric materials have remained one of the major focal points of condensed matter physics and materials science for over 50 years. In the last 20 years, the development of voltage-modulated scanning probe microscopy techniques, exemplified by Piezoresponse force microscopy (PFM) and associated time- and voltage spectroscopies, opened a pathway to explore these materials on a single-digit nanometer level. Consequently, domain structures and walls and polarization dynamics can now be imaged in real space. More generally, PFM has allowed studying electromechanical coupling in a broad variety of materials ranging from ionics to biological systems.

Spontaneous generation of singularities in paraxial optical fields.

PubMed

Aiello, Andrea

2016-04-01

In nonrelativistic quantum mechanics, the spontaneous generation of singularities in smooth and finite wave functions is a well understood phenomenon also occurring for free particles. We use the familiar analogy between the two-dimensional Schrödinger equation and the optical paraxial wave equation to define a new class of square-integrable paraxial optical fields that develop a spatial singularity in the focal point of a weakly focusing thin lens. These fields are characterized by a single real parameter whose value determines the nature of the singularity. This novel field enhancement mechanism may stimulate fruitful research for diverse technological and scientific applications.

Multi-facet concentrator of solar setup for irradiating the objects placed in a target plane with solar light

DOEpatents

Lewandowski, Allan A.; Yampolskiy, Vladislav; Alekseev, Valerie; Son, Valentin

2001-01-01

According to the proposed invention, this technical result is achieved so that many-facet concentrator of a solar setup for exposure of objects, placed in a target plane, to the action of solar radiation containing a supporting frame and facets differing by that the facets of the concentrator are chosen with spherical focusing reflective surfaces of equal focal lengths and with selective coatings reflecting a desired spectral fraction of solar radiation, and are arranged on the supporting frame symmetrically with respect to the common axis of the concentrator, their optical axes being directed to the single point on the optical axis of the concentrator located before the nominal focus point of the concentrator and determining the position of arranging the target plane.

Micro Ring Grating Spectrometer with Adjustable Aperture

NASA Technical Reports Server (NTRS)

Park, Yeonjoon (Inventor); King, Glen C. (Inventor); Elliott, James R. (Inventor); Choi, Sang H. (Inventor)

2012-01-01

A spectrometer includes a micro-ring grating device having coaxially-aligned ring gratings for diffracting incident light onto a target focal point, a detection device for detecting light intensity, one or more actuators, and an adjustable aperture device defining a circular aperture. The aperture circumscribes a target focal point, and directs a light to the detection device. The aperture device is selectively adjustable using the actuators to select a portion of a frequency band for transmission to the detection device. A method of detecting intensity of a selected band of incident light includes directing incident light onto coaxially-aligned ring gratings of a micro-ring grating device, and diffracting the selected band onto a target focal point using the ring gratings. The method includes using an actuator to adjust an aperture device and pass a selected portion of the frequency band to a detection device for measuring the intensity of the selected portion.

Focal Length Controllable Ultrasonic Transducer Using Bimorph-Type Bending Actuator

NASA Astrophysics Data System (ADS)

Chae, Min-Ku; Kim, Moo-Joon; Ha, Kang-Lyeol; Lee, Chai-Bong

2003-05-01

Using a bimorph-type bending actuator, we propose a new method for controlling the focal length of a transducer by electric DC voltage. We designed two focal length controllable ultrasonic transducers with actuators, a line-focus and a point-focus transducer. The polyvinylidene fluoride (PVDF) piezoelectric type polymer film is used for transmitting and receiving of ultrasonic signals. Using the new method, it is confirmed by investigation of the underwater acoustic field that the focal length can be controlled to within 10% of the radius of the transducer curvature.

Monolithic in-based III-V compound semiconductor focal plane array cell with single stage CCD output

NASA Technical Reports Server (NTRS)

Fossum, Eric R. (Inventor); Cunningham, Thomas J. (Inventor); Krabach, Timothy N. (Inventor); Staller, Craig O. (Inventor)

1994-01-01

A monolithic semiconductor imager includes an indium-based III-V compound semiconductor monolithic active layer of a first conductivity type, an array of plural focal plane cells on the active layer, each of the focal plane cells including a photogate over a top surface of the active layer, a readout circuit dedicated to the focal plane cell including plural transistors formed monolithically with the monolithic active layer and a single-stage charge coupled device formed monolithically with the active layer between the photogate and the readout circuit for transferring photo-generated charge accumulated beneath the photogate during an integration period to the readout circuit. The photogate includes thin epitaxial semiconductor layer of a second conductivity type overlying the active layer and an aperture electrode overlying a peripheral portion of the thin epitaxial semiconductor layer, the aperture electrode being connectable to a photogate bias voltage.

Evaluation and Validation (E&V) Team Public Report. Volume 2.

DTIC Science & Technology

1985-11-30

Byron, Countess of Lovelace. The Countess was an associate of Charles Babbage and is presumed to be the world’s first programmer (Barnes, 1982:2...by DDT&E, STARS, and AJPO personnel, as appropriate. 4.20.9 Focal Point The DDT&E and STARS focal points, respectively, are indicated below Charles K...Technology For Adaptable, Reliable Systems Major Charles W. Lillie from Headquarters Air Force Systems Command gave a presentation concerning Software For

Quantum-Well Infrared Photodetector (QWIP) Focal Plane Assembly

NASA Technical Reports Server (NTRS)

Jhabvala, Murzy; Jhabvala, Christine A.; Ewin, Audrey J.; Hess, Larry A.; Hartmann, Thomas M.; La, Anh T.

2012-01-01

A paper describes the Thermal Infrared Sensor (TIRS), a QWIP-based instrument intended to supplement the Operational Land Imager (OLI) for the Landsat Data Continuity Mission (LDCM). The TIRS instrument is a far-infrared imager operating in the pushbroom mode with two IR channels: 10.8 and 12 microns. The focal plane will contain three 640x512 QWIP arrays mounted on a silicon substrate. The silicon substrate is a custom-fabricated carrier board with a single layer of aluminum interconnects. The general fabrication process starts with a 4-in. (approx.10-cm) diameter silicon wafer. The wafer is oxidized, a single substrate contact is etched, and aluminum is deposited, patterned, and alloyed. This technology development is aimed at incorporating three large-format infrared detecting arrays based on GaAs QWIP technology onto a common focal plane with precision alignment of all three arrays. This focal plane must survive the rigors of flight qualification and operate at a temperature of 43 K (-230 C) for five years while orbiting the Earth. The challenges presented include ensuring thermal compatibility among all the components, designing and building a compact, somewhat modular system and ensuring alignment to very tight levels. The multi-array focal plane integrated onto a single silicon substrate is a new application of both QWIP array development and silicon wafer scale integration. The Invar-based assembly has been tested to ensure thermal reliability.

High precise measurement of tiny angle dimensional holes for the unit-holes of the LAMOST Focal Plane Plate

NASA Astrophysics Data System (ADS)

Zhou, Zengxiang; Jin, Yi; Zhai, Chao; Xing, Xiaozheng

2008-07-01

In the LAMOST project, the unit-holes on the Focal Plane Plate are the final installation location of the optical fiber positioning system. Theirs precision will influence the observation efficiency of the LAMOST. For the unique requirements, the unit-holes on the Focal Plane Plate are composed by a series of tiny angle dimensional holes which dimensional angle are between 16' to 2.5°. According to these requirements, the measurement of the tiny angle dimensional holes for the unit-holes needs to less than 3'. And all the unit-holes point to the virtual sphere center of the Focal Plane Plate. To that end, the angle departure of the unit-holes axis is changed to the distance from the virtual sphere center of Focal Plane Plate to the unit-holes axis. That is the better way to evaluate the technical requirements of the dimensional angle errors. In the measuring process, common measuring methods do not fit for the tiny angle dimensional hole by CMM(coordinate measurement machine). An extraordinary way to solve this problem is to insert a measuring stick into a unit-hole, with a target ball on the stick. Then measure the low point of the ball center and pull out the stick for the high station of center. Finally, calculate the two points for the unit-hole axis to get the angle departure. But on the other hand, use this methods will bring extra errors for the measuring stick and the target ball. For better analysis this question, a series experiments are mentioned in this paper, which testify that the influence of the measure implement is little. With increasing the distance between the low point and the high point position in the measuring process should enhance the accuracy of dimensional angle measurement.

Focal shift and the axial optical coordinate for high-aperture systems of finite Fresnel number.

PubMed

Sheppard, Colin J R; Török, Peter

2003-11-01

Analytic expressions are given for the on-axis intensity predicted by the Rayleigh-Sommerfeld and Kirchhoff diffraction integrals for a scalar optical system of high numerical aperture and finite value of Fresnel number. A definition of the axial optical coordinate is introduced that is valid for finite values of Fresnel number, for high-aperture systems, and for observation points distant from the focus. The focal shift effect is reexamined. For the case when the focal shift is small, explicit expressions are given for the focal shift and the axial peak in intensity.

Generation of a focused hollow beam by an 2π-phase plate and its application in atom or molecule optics

NASA Astrophysics Data System (ADS)

Xia, Yong; Yin, Jianping

2005-03-01

We propose a new scheme to generate a focusing hollow beam (FHB) by use of an azimuthally distributed 2π-phase plate and a convergent thin lens. From the Fresnel diffraction theory, we calculate the intensity distributions of the FHB in free propagation space and study the relationship between the waist w0 of the incident Gaussian beam (or the focal length f of the lens) and the dark spot size (or the beam radius) at the focal point and the relationship between the maximum radial intensity of the FHB and the dark spot size (or the beam radius) at the focal point, respectively. Our study shows that the FHB can be used to cool and trap neutral atoms by intensity-gradient-induced Sisyphus cooling due to an extremely high intensity gradient of the FHB itself near the focal point, or to guide and focus a cold molecular beam. We also calculate the optical potential of the blue-detuned FHB for 85Rb atoms and find that in the focal plane, the smaller the dark spot size of the FHB is, the higher the optical potential is, and the greater the corresponding optimal detuning δ is; these qualities are beneficial to an atomic lens not only because it is profitable to obtain an atomic lens with a higher resolution, but also because it is helpful to reduce the spontaneous photon-scattering effect of atoms in the FHB.

Micro-Fresnel Zone Plate Optical Devices Using Densely Accumulated Ray Points

NASA Technical Reports Server (NTRS)

Choi, Sang H. (Inventor); Park, Yeonjoon (Inventor); King, Glen C. (Inventor); Elliott, James R. (Inventor)

2011-01-01

An embodiment generally relates to an optical device suitable for use with an optical medium for the storage and retrieval of data. The optical device includes an illumination means for providing a beam of optical radiation of wavelength .lamda. and an optical path that the beam of optical radiation follows. The optical device also includes a diffractive optical element defined by a plurality of annular sections. The plurality of annular sections having a first material alternately disposed with a plurality of annular sections comprising a second material. The diffractive optical element generates a plurality of focal points and densely accumulated ray points with phase contrast phenomena and the optical medium is positioned at a selected focal point or ray point of the diffractive optical element.

Studies on design of 351  nm focal plane diagnostic system prototype and focusing characteristic of SGII-upgraded facility at half achievable energy performance.

PubMed

Liu, Chong; Ji, Lailin; Yang, Lin; Zhao, Dongfeng; Zhang, Yanfeng; Liu, Dong; Zhu, Baoqiang; Lin, Zunqi

2016-04-01

In order to obtain the intensity distribution of a 351 nm focal spot and smoothing by spectral dispersion (SSD) focal plane profile of a SGII-upgraded facility, a type of off-axis imaging system with three spherical mirrors, suitable for a finite distance source point to be imaged near the diffraction limit has been designed. The quality factor of the image system is 1.6 times of the diffraction limit tested by a 1053 nm point source. Because of the absence of a 351 nm point source, we can use a Collins diffraction imaging integral with respect to λ=351  nm, corresponding to a quality factor that is 3.8 times the diffraction limit at 351 nm. The calibration results show that at least the range of ±10  mrad of view field angle and ±50  mm along the axial direction around the optimum object distance can be satisfied with near diffraction limited image that is consistent with the design value. Using this image system, the No. 2 beam of the SGII-upgraded facility has been tested. The test result of the focal spot of final optics assembly (FOA) at 351 nm indicates that about 80% of energy is encompassed in 14.1 times the diffraction limit, while the output energy of the No. 2 beam is 908 J at 1053 nm. According to convolution theorem, the true value of a 351 nm focal spot of FOA is about 12 times the diffraction limit because of the influence of the quality factor. Further experimental studies indicate that the RMS value along the smoothing direction is less than 15.98% in the SSD spot test experiment. Computer simulations show that the quality factor of the image system used in the experiment has almost no effect on the SSD focal spot test. The image system can remarkably distort the SSD focal spot distribution under the circumstance of the quality factor 15 times worse than the diffraction limit. The distorted image shows a steep slope in the contour of the SSD focal spot along the smoothing direction that otherwise has a relatively flat top region around the focal spot center.

A finite element analysis of the effect of electrode area and inter-electrode distance on the spatial distribution of the current density in tDCS

NASA Astrophysics Data System (ADS)

Faria, Paula; Hallett, Mark; Cavaleiro Miranda, Pedro

2011-12-01

We investigated the effect of electrode area and inter-electrode distance on the spatial distribution of the current density in transcranial direct current stimulation (tDCS). For this purpose, we used the finite element method to compute the distribution of the current density in a four-layered spherical head model using various electrode montages, corresponding to a range of electrode sizes and inter-electrode distances. We found that smaller electrodes required slightly less current to achieve a constant value of the current density at a reference point on the brain surface located directly under the electrode center. Under these conditions, smaller electrodes also produced a more focal current density distribution in the brain, i.e. the magnitude of the current density fell more rapidly with distance from the reference point. The combination of two electrodes with different areas produced an asymmetric current distribution that could lead to more effective and localized neural modulation under the smaller electrode than under the larger one. Focality improved rapidly with decreasing electrode size when the larger electrode sizes were considered but the improvement was less marked for the smaller electrode sizes. Also, focality was not affected significantly by inter-electrode distance unless two large electrodes were placed close together. Increasing the inter-electrode distance resulted in decreased shunting of the current through the scalp and the cerebrospinal fluid, and decreasing electrode area resulted in increased current density on the scalp under the edges of the electrode. Our calculations suggest that when working with conventional electrodes (25-35 cm2), one of the electrodes should be placed just 'behind' the target relative to the other electrode, for maximum current density on the target. Also electrodes with areas in the range 3.5-12 cm2 may provide a better compromise between focality and current density in the scalp than the traditional electrodes. Finally, the use of multiple small return electrodes may be more efficient than the use of a single large return electrode.

Point spread function and depth-invariant focal sweep point spread function for plenoptic camera 2.0.

PubMed

Jin, Xin; Liu, Li; Chen, Yanqin; Dai, Qionghai

2017-05-01

This paper derives a mathematical point spread function (PSF) and a depth-invariant focal sweep point spread function (FSPSF) for plenoptic camera 2.0. Derivation of PSF is based on the Fresnel diffraction equation and image formation analysis of a self-built imaging system which is divided into two sub-systems to reflect the relay imaging properties of plenoptic camera 2.0. The variations in PSF, which are caused by changes of object's depth and sensor position variation, are analyzed. A mathematical model of FSPSF is further derived, which is verified to be depth-invariant. Experiments on the real imaging systems demonstrate the consistency between the proposed PSF and the actual imaging results.

Focal Points, Endogenous Processes, and Exogenous Shocks in the Autism Epidemic

PubMed Central

Liu, Kayuet; Bearman, Peter S.

2014-01-01

Autism prevalence has increased rapidly in the United States during the past two decades. We have previously shown that the diffusion of information about autism through spatially proximate social relations has contributed significantly to the epidemic. This study expands on this finding by identifying the focal points for interaction that drive the proximity effect on subsequent diagnoses. We then consider how diffusion dynamics through interaction at critical focal points, in tandem with exogenous shocks, could have shaped the spatial dynamics of autism in California. We achieve these goals through an empirically calibrated simulation model of the whole population of 3- to 9-year-olds in California. We show that in the absence of interaction at these foci—principally malls and schools—we would not observe an autism epidemic. We also explore the idea that epigenetic changes affecting one generation in the distal past could shape the precise spatial patterns we observe among the next generation. PMID:26166907

The Strong Effects Of On-Axis Focal Shift And Its Nonlinear Variation In Ultrasound Beams Radiated By Low Fresnel Number Transducers

NASA Astrophysics Data System (ADS)

Makov, Y. N.; Espinosa, V.; Sánchez-Morcillo, V. J.; Ramis, J.; Cruañes, J.; Camarena, F.

2006-05-01

On the basis of theoretical concepts, an accurate and complete experimental and numerical examination of the on-axis distribution and the corresponding temporal profiles for low-Fresnel-number focused ultrasound beams under increasing transducer input voltage has been performed. For a real focusing transducer with sufficiently small Fresnel number, a strong initial (linear) shift of the main on-axis pressure maximum from geometrical focal point towards the transducer, and its following displacement towards the focal point and backward motion as the driving transducer voltage increase until highly nonlinear regimes were fixed. The simultaneous monitoring of the temporal waveform modifications determines the real roles and interplay between different nonlinear effects (refraction and attenuation) in the observed dynamics of on-axis pressure maximum. The experimental results are in good agreement with numerical solutions of KZK equation, confirming that the observed dynamic shift of the maximum pressure point is related only to the interplay between diffraction, dissipation and nonlinearity of the acoustic wave.

Design of compact electromagnetic impulse radiating antenna for melanoma treatment.

PubMed

Arockiasamy, Petrishia; Mohan, Sasikala

2016-01-01

Cancer therapy is one of the several new applications which use nanosecond and subnanosecond high voltage pulses. New treatment based on electromagnetic (EM) fields have been developed as non-surgical and minimally invasive treatments of tumors. In particular, subnanosecond pulses can introduce important non-thermal changes in cell biology, especially the permeabilization of the cell membrane. The motivation behind this work is to launch intense subnanosecond pulses to the target (tumors) non-invasively. This works focuses on the design of a compact intense pulsed EM radiating antenna. In tense EM waves radiated at the first focal point of the Prolate Spheroidal Reflector (PSR) are focused at the second focal point where the target (tumor) is present. Two antennas with PSR but fed with different compact wave radiator are designed to focus pulsed field at the second focal point. The PSR with modified bicone antenna feed and PSR with elliptically tapered horn antenna feed are designed. The design parameters and radiation performance are discussed.

Green's function and image system for the Laplace operator in the prolate spheroidal geometry

NASA Astrophysics Data System (ADS)

Xue, Changfeng; Deng, Shaozhong

2017-01-01

In the present paper, electrostatic image theory is studied for Green's function for the Laplace operator in the case where the fundamental domain is either the exterior or the interior of a prolate spheroid. In either case, an image system is developed to consist of a point image inside the complement of the fundamental domain and an additional symmetric continuous surface image over a confocal prolate spheroid outside the fundamental domain, although the process of calculating such an image system is easier for the exterior than for the interior Green's function. The total charge of the surface image is zero and its centroid is at the origin of the prolate spheroid. In addition, if the source is on the focal axis outside the prolate spheroid, then the image system of the exterior Green's function consists of a point image on the focal axis and a line image on the line segment between the two focal points.

A Sandia weapon review bulletin : defense programs, Autumn 1992.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1992-09-01

Topics in this issue: (1) Focal Point and STEP. Sandia National Laboratories has always focused its advanced weapon development not only on future weapon needs, but also on the engineering and manufacturing sciences needed to meet them. Both areas are changing dramatically. As the nation dismantles many of its warheads, it becomes essential that those that remain are increasingly reliable, secure, capable, and safe. And as development resources diminish, it becomes vital that they are applied to the most critical technologies in a disciplined manner. The mission of the Focal Point program and the Stockpile Transition Enabling Program (STEP) ismore » to develop processes for meeting these challenges. Focal Point offers a decision-making process for allocating Sandia's resources to meets its defense programs strategic goals. (2) Defense Programs news in brief. (3) Dismantling the nuclear stockpile. (4) W88/MK5: Arming, Fuzing, and Firing system meets all requirements and goals. (5) The Common Radar Fuze. (6) Insertable-explosive arming of firing sets. (7) Preparing for fewer underground tests.« less

Real-time adaptive methods for treatment of mobile organs by MRI-controlled high-intensity focused ultrasound.

PubMed

de Senneville, Baudouin Denis; Mougenot, Charles; Moonen, Chrit T W

2007-02-01

Focused ultrasound (US) is a unique and noninvasive technique for local deposition of thermal energy deep inside the body. MRI guidance offers the additional benefits of excellent target visualization and continuous temperature mapping. However, treating a moving target poses severe problems because 1) motion-related thermometry artifacts must be corrected, 2) the US focal point must be relocated according to the target displacement. In this paper a complete MRI-compatible, high-intensity focused US (HIFU) system is described together with adaptive methods that allow continuous MR thermometry and therapeutic US with real-time tracking of a moving target, online motion correction of the thermometry maps, and regional temperature control based on the proportional, integral, and derivative method. The hardware is based on a 256-element phased-array transducer with rapid electronic displacement of the focal point. The exact location of the target during US firing is anticipated using automatic analysis of periodic motions. The methods were tested with moving phantoms undergoing either rigid body or elastic periodical motions. The results show accurate tracking of the focal point. Focal and regional temperature control is demonstrated with a performance similar to that obtained with stationary phantoms. Copyright (c) 2007 Wiley-Liss, Inc.

In-Situ Real-Time Focus Detection during Laser Processing Using Double-Hole Masks and Advanced Image Sensor Software

PubMed Central

Hoang, Phuong Le; Ahn, Sanghoon; Kim, Jeng-o; Kang, Heeshin; Noh, Jiwhan

2017-01-01

In modern high-intensity ultrafast laser processing, detecting the focal position of the working laser beam, at which the intensity is the highest and the beam diameter is the lowest, and immediately locating the target sample at that point are challenging tasks. A system that allows in-situ real-time focus determination and fabrication using a high-power laser has been in high demand among both engineers and scientists. Conventional techniques require the complicated mathematical theory of wave optics, employing interference as well as diffraction phenomena to detect the focal position; however, these methods are ineffective and expensive for industrial application. Moreover, these techniques could not perform detection and fabrication simultaneously. In this paper, we propose an optical design capable of detecting the focal point and fabricating complex patterns on a planar sample surface simultaneously. In-situ real-time focus detection is performed using a bandpass filter, which only allows for the detection of laser transmission. The technique enables rapid, non-destructive, and precise detection of the focal point. Furthermore, it is sufficiently simple for application in both science and industry for mass production, and it is expected to contribute to the next generation of laser equipment, which can be used to fabricate micro-patterns with high complexity. PMID:28671566

The role of transvaginal power Doppler ultrasound in the differential diagnosis of benign intrauterine focal lesions.

PubMed

Cogendez, Ebru; Eken, Meryem Kurek; Bakal, Nuray; Gun, Ismet; Kaygusuz, Ecmel Isik; Karateke, Ates

2015-10-01

The purpose of this prospective study was to assess the role of power Doppler imaging in the differential diagnosis of benign intrauterine focal lesions such as endometrial polyps and submucous myomas using the characteristics of power Doppler flow mapping. A total of 480 premenopausal patients with abnormal uterine bleeding were evaluated by transvaginal ultrasonography (TVS) searching for intrauterine pathology. Sixty-four patients with a suspicious focal endometrial lesion received saline infusion sonography (SIS) after TVS. Fifty-eight patients with focal endometrial lesions underwent power Doppler ultrasound (PDUS). Three different vascular flow patterns were defined: Single vessel pattern, multiple vessel pattern, and circular flow pattern. Finally, hysteroscopic resection was performed in all cases, and Doppler flow characteristics were then compared with the final histopathological findings. Histopathological results were as follows: endometrial polyp: 40 (69 %), submucous myoma: 18 (31 %). Of the cases with endometrial polyps, 80 % demonstrated a single vessel pattern, 7.5 % a multiple vessel pattern, and 0 % a circular pattern. Vascularization was not observed in 12.5 % of patients with polyps. Of the cases with submucousal myomas, 72.2 % demonstrated a circular flow pattern, 27.8 % a multiple vessel pattern, and none of them showed a single vessel pattern. The sensitivity, specificity, and positive and negative predictive values of the single vessel pattern in diagnosing endometrial polyps were 80, 100, 100, and 69.2 %, respectively; and for the circular pattern in diagnosing submucous myoma, these were 72.2, 100, 100, and 88.9 %, respectively. Power Doppler blood flow mapping is a useful, practical, and noninvasive diagnostic method for the differential diagnosis of benign intrauterine focal lesions. Especially in cases of recurrent abnormal uterine bleeding, recurrent abortion, and infertility, PDUS can be preferred as a first-line diagnostic method.

In-situ coupling between kinase activities and protein dynamics within single focal adhesions

NASA Astrophysics Data System (ADS)

Wu, Yiqian; Zhang, Kaiwen; Seong, Jihye; Fan, Jason; Chien, Shu; Wang, Yingxiao; Lu, Shaoying

2016-07-01

The dynamic activation of oncogenic kinases and regulation of focal adhesions (FAs) are crucial molecular events modulating cell adhesion in cancer metastasis. However, it remains unclear how these events are temporally coordinated at single FA sites. Therefore, we targeted fluorescence resonance energy transfer (FRET)-based biosensors toward subcellular FAs to report local molecular events during cancer cell adhesion. Employing single FA tracking and cross-correlation analysis, we quantified the dynamic coupling characteristics between biochemical kinase activities and structural FA within single FAs. We show that kinase activations and FA assembly are strongly and sequentially correlated, with the concurrent FA assembly and Src activation leading focal adhesion kinase (FAK) activation by 42.6 ± 12.6 sec. Strikingly, the temporal coupling between kinase activation and individual FA assembly reflects the fate of FAs at later stages. The FAs with a tight coupling tend to grow and mature, while the less coupled FAs likely disassemble. During FA disassembly, however, kinase activations lead the disassembly, with FAK being activated earlier than Src. Therefore, by integrating subcellularly targeted FRET biosensors and computational analysis, our study reveals intricate interplays between Src and FAK in regulating the dynamic life of single FAs in cancer cells.

Positive focal shift of gallium nitride high contrast grating focusing reflectors

NASA Astrophysics Data System (ADS)

He, Shumin; Wang, Zhenhai; Liu, Qifa

2016-09-01

We design a type of metasurfaces capable of serving as a visible-light focusing reflector based on gallium nitride (GaN) high contrast gratings (HCGs). The wavefront of the reflected light is precisely manipulated by spatial variation of the grating periods along the subwavelength ridge array to achieve light focusing. Different from conventional negative focal shift effect, a positive focal shift is observed in such focusing reflectors. Detailed investigations of the influence of device size on the focusing performance, especially the focal length, are preformed via a finite element method . The results show that all performance parameters are greatly affected by the reflector size. A more concentrated focal point, or a better focusing capability, can be achieved by larger size. With increasing reflector size, the achieved focal length decreases and gradually approaches to the design, thus the corresponding positive focal shift decreases. Our results are helpful for understanding the visible-light control of the planar HCG-based focusing reflectors.

Television monitor field shifter and an opto-electronic method for obtaining a stereo image of optimal depth resolution and reduced depth distortion on a single screen

NASA Technical Reports Server (NTRS)

Diner, Daniel B. (Inventor)

1989-01-01

A method and apparatus is developed for obtaining a stereo image with reduced depth distortion and optimum depth resolution. Static and dynamic depth distortion and depth resolution tradeoff is provided. Cameras obtaining the images for a stereo view are converged at a convergence point behind the object to be presented in the image, and the collection-surface-to-object distance, the camera separation distance, and the focal lengths of zoom lenses for the cameras are all increased. Doubling the distances cuts the static depth distortion in half while maintaining image size and depth resolution. Dynamic depth distortion is minimized by panning a stereo view-collecting camera system about a circle which passes through the convergence point and the camera's first nodal points. Horizontal field shifting of the television fields on a television monitor brings both the monitor and the stereo views within the viewer's limit of binocular fusion.

The 1982 control network of Mars

NASA Technical Reports Server (NTRS)

Davies, M. E.; Katayama, F. Y.

1983-01-01

Attention is given to a planet-wide control network of Mars that was computed in September 1982 using a large single-block analytical triangulation with 47,524 measurements of 6853 control points on 1054 Mariner 9 and 757 Viking pictures. In all, 19,139 normal equations were solved, with a resulting standard error of measurement of 18.06 microns. The control points identified by name and letter designation are given, as are the aerographic coordinates of the control points. In addition, the coordinates of the Viking I lander site are given: latitude, 22.480 deg; longitude, 47.962 deg (radius, 3389.32 km). This study expands and updates the previously published network (1978). It is noted that the computation differs in many respects from standard aerial mapping photogrammetric practice. In comparison with aerial mapping photography, the television formats are small and the focal lengths are long; stereo coverage is rare, the scale of the pictures varies greatly, and the residual camera distortions are large.

Optimization of confocal laser induced fluorescence for long focal length applications

NASA Astrophysics Data System (ADS)

Jemiolo, Andrew J.; Henriquez, Miguel F.; Thompson, Derek S.; Scime, Earl E.

2017-10-01

Laser induced fluorescence (LIF) is a non-perturbative diagnostic for measuring ion and neutral particle velocities and temperatures in a plasma. The conventional method for single-photon LIF requires intersecting optical paths for light injection and collection. The multiple vacuum windows needed for such measurements are unavailable in many plasma experiments. Confocal LIF eliminates the need for perpendicular intersecting optical paths by using concentric injection and collection paths through a single window. One of the main challenges with using confocal LIF is achieving high resolution measurements at the longer focal lengths needed for many plasma experiments. We present confocal LIF measurements in HELIX, a helicon plasma experiment at West Virginia University, demonstrating spatial resolution dependence on focal length and spatial filtering. By combining aberration mitigating optics with spatial filtering, our results show high resolution measurements at focal lengths of 0.5 m, long enough to access the interiors of many laboratory plasma experiments. This work was supported by U.S. National Science Foundation Grant No. PHY-1360278.

Analysis of Rapid Multi-Focal Zone ARFI Imaging

PubMed Central

Rosenzweig, Stephen; Palmeri, Mark; Nightingale, Kathryn

2015-01-01

Acoustic radiation force impulse (ARFI) imaging has shown promise for visualizing structure and pathology within multiple organs; however, because the contrast depends on the push beam excitation width, image quality suffers outside of the region of excitation. Multi-focal zone ARFI imaging has previously been used to extend the region of excitation (ROE), but the increased acquisition duration and acoustic exposure have limited its utility. Supersonic shear wave imaging has previously demonstrated that through technological improvements in ultrasound scanners and power supplies, it is possible to rapidly push at multiple locations prior to tracking displacements, facilitating extended depth of field shear wave sources. Similarly, ARFI imaging can utilize these same radiation force excitations to achieve tight pushing beams with a large depth of field. Finite element method simulations and experimental data are presented demonstrating that single- and rapid multi-focal zone ARFI have comparable image quality (less than 20% loss in contrast), but the multi-focal zone approach has an extended axial region of excitation. Additionally, as compared to single push sequences, the rapid multi-focal zone acquisitions improve the contrast to noise ratio by up to 40% in an example 4 mm diameter lesion. PMID:25643078

Site Characterization and Analysis Penetrometer System (SCAPS) Heavy Metal Sensors

DTIC Science & Technology

2003-04-01

gigawatts per square centimeter (GW/cm2). Within the small volume about the focal point, rapid heating, vaporization, and ionization of a small amount of the...2001). Briefly, the light emitted from the fiber in the probe is collimated, turned by a quartz prism, and focused by a short- focal -length quartz 5...are decoupled using the configuration shown in Figure 1. The excitation beam is focused by a 25-cm focal length lens through a 2-inch aluminum mirror

Using frequency response functions to manage image degradation from equipment vibration in the Daniel K. Inouye Solar Telescope

NASA Astrophysics Data System (ADS)

McBride, William R.; McBride, Daniel R.

2016-08-01

The Daniel K Inouye Solar Telescope (DKIST) will be the largest solar telescope in the world, providing a significant increase in the resolution of solar data available to the scientific community. Vibration mitigation is critical in long focal-length telescopes such as the Inouye Solar Telescope, especially when adaptive optics are employed to correct for atmospheric seeing. For this reason, a vibration error budget has been implemented. Initially, the FRFs for the various mounting points of ancillary equipment were estimated using the finite element analysis (FEA) of the telescope structures. FEA analysis is well documented and understood; the focus of this paper is on the methods involved in estimating a set of experimental (measured) transfer functions of the as-built telescope structure for the purpose of vibration management. Techniques to measure low-frequency single-input-single-output (SISO) frequency response functions (FRF) between vibration source locations and image motion on the focal plane are described. The measurement equipment includes an instrumented inertial-mass shaker capable of operation down to 4 Hz along with seismic accelerometers. The measurement of vibration at frequencies below 10 Hz with good signal-to-noise ratio (SNR) requires several noise reduction techniques including high-performance windows, noise-averaging, tracking filters, and spectral estimation. These signal-processing techniques are described in detail.

Challenges in photon-starved space astronomy in a harsh radiation environment using CCDs

NASA Astrophysics Data System (ADS)

Hall, David J.; Bush, Nathan; Murray, Neil; Gow, Jason; Clarke, Andrew; Burgon, Ross; Holland, Andrew

2015-09-01

The Charge Coupled Device (CCD) has a long heritage for imaging and spectroscopy in many space astronomy missions. However, the harsh radiation environment experienced in orbit creates defects in the silicon that capture the signal being transferred through the CCD. This radiation damage has a detrimental impact on the detector performance and requires carefully planned mitigation strategies. The ESA Gaia mission uses 106 CCDs, now orbiting around the second Lagrange point as part of the largest focal-plane ever launched. Following readout, signal electrons will be affected by the traps generated in the devices from the radiation environment and this degradation will be corrected for using a charge distortion model. ESA's Euclid mission will contain a focal plane of 36 CCDs in the VIS instrument. Moving further forwards, the World Space Observatory (WSO) UV spectrographs and the WFIRST-AFTA coronagraph intend to look at very faint sources in which mitigating the impact of traps on the transfer of single electron signals will be of great interest. Following the development of novel experimental and analysis techniques, one is now able to study the impact of radiation on the detector to new levels of detail. Through a combination of TCAD simulations, defect studies and device testing, we are now probing the interaction of single electrons with individual radiation-induced traps to analyse the impact of radiation in photon-starved applications.

Types of traumatic brain injury and regional cerebral blood flow assessed by 99mTc-HMPAO SPECT.

PubMed

Yamakami, I; Yamaura, A; Isobe, K

1993-01-01

To investigate the relationship between focal and diffuse traumatic brain injury (TBI) and regional cerebral blood flow (rCBF), rCBF changes in the first 24 hours post-trauma were studied in 12 severe head trauma patients using single photon emission computed tomography (SPECT) with 99mtechnetium-hexamethyl propyleneamine oxime. Patients were classified as focal or diffuse TBI based on x-ray computed tomographic (X-CT) findings and neurological signs. In six patients with focal damage, SPECT demonstrated 1) perfusion defect (focal severe ischemia) in the brain region larger than the brain contusion by X-CT, 2) hypoperfusion (focal CBF reduction) in the brain region without abnormality by X-CT, and 3) localized hyperperfusion (focal CBF increase) in the surgically decompressed brain after decompressive craniectomy. Focal damage may be associated with a heterogeneous CBF change by causing various focal CBF derangements. In six patients with diffuse damage, SPECT revealed hypoperfusion in only one patient. Diffuse damage may be associated with a homogeneous CBF change by rarely causing focal CBF derangements. The type of TBI, focal or diffuse, determines the type of CBF change, heterogeneous or homogeneous, in the acute severe head trauma patient.

Signal improvement in multiphoton microscopy by reflection with simple mirrors near the sample

NASA Astrophysics Data System (ADS)

Rehberg, Markus; Krombach, Fritz; Pohl, Ulrich; Dietzel, Steffen

2010-03-01

In conventional fluorescence or confocal microscopy, emitted light is generated not only in the focal plane but also above and below. The situation is different in multiphoton-induced fluorescence and multiphoton-induced higher harmonic generation. Here, restriction of signal generation to a single focal point permits that all emitted photons can contribute to image formation if collected, regardless of their path through the specimen. Often, the intensity of the emitted light is rather low in biological specimens. We present a method to significantly increase the fraction of photons collected by an epi (backward) detector by placing a simple mirror, an aluminum-coated coverslip, directly under the sample. Samples investigated include fluorescent test slides, collagen gels, and thin-layered, intact mouse skeletal muscles. Quantitative analysis revealed an intensity increase of second- and third-harmonic generated signal in skeletal muscle of nine- and sevenfold respectively, and of fluorescent signal in test slides of up to twofold. Our approach thus allows significant signal improvement also for situations were a forward detection is impossible, e.g., due to the anatomy of animals in intravital microscopy.

Extreme depth-of-field intraocular lenses

NASA Astrophysics Data System (ADS)

Baker, Kenneth M.

1996-05-01

A new technology brings the full aperture single vision pseudophakic eye's effective hyperfocal distance within the half-meter range. A modulated index IOL containing a subsurface zeroth order coherent microlenticular mosaic defined by an index gradient adds a normalizing function to the vergences or parallactic angles of incoming light rays subtended from field object points and redirects them, in the case of near-field images, to that of far-field images. Along with a scalar reduction of the IOL's linear focal range, this results in an extreme depth of field with a narrow depth of focus and avoids the focal split-up, halo, and inherent reduction in contrast of multifocal IOLs. A high microlenticular spatial frequency, which, while still retaining an anisotropic medium, results in a nearly total zeroth order propagation throughout the visible spectrum. The curved lens surfaces still provide most of the refractive power of the IOL, and the unique holographic fabrication technology is especially suitable not only for IOLs but also for contact lenses, artificial corneas, and miniature lens elements for cameras and other optical devices.

DUSTER: demonstration of an integrated LWIR-VNIR-SAR imaging system

NASA Astrophysics Data System (ADS)

Wilson, Michael L.; Linne von Berg, Dale; Kruer, Melvin; Holt, Niel; Anderson, Scott A.; Long, David G.; Margulis, Yuly

2008-04-01

The Naval Research Laboratory (NRL) and Space Dynamics Laboratory (SDL) are executing a joint effort, DUSTER (Deployable Unmanned System for Targeting, Exploitation, and Reconnaissance), to develop and test a new tactical sensor system specifically designed for Tier II UAVs. The system is composed of two coupled near-real-time sensors: EyePod (VNIR/LWIR ball gimbal) and NuSAR (L-band synthetic aperture radar). EyePod consists of a jitter-stabilized LWIR sensor coupled with a dual focal-length optical system and a bore-sighted high-resolution VNIR sensor. The dual focal-length design coupled with precision pointing an step-stare capabilities enable EyePod to conduct wide-area survey and high resolution inspection missions from a single flight pass. NuSAR is being developed with partners Brigham Young University (BYU) and Artemis, Inc and consists of a wideband L-band SAR capable of large area survey and embedded real-time image formation. Both sensors employ standard Ethernet interfaces and provide geo-registered NITFS output imagery. In the fall of 2007, field tests were conducted with both sensors, results of which will be presented.

Photophoretic trapping of absorbing particles in air and measurement of their single-particle Raman spectra.

PubMed

Pan, Yong-Le; Hill, Steven C; Coleman, Mark

2012-02-27

A new method is demonstrated for optically trapping micron-sized absorbing particles in air and obtaining their single-particle Raman spectra. A 488-nm Gaussian beam from an Argon ion laser is transformed by conical lenses (axicons) and other optics into two counter-propagating hollow beams, which are then focused tightly to form hollow conical beams near the trapping region. The combination of the two coaxial conical beams, with focal points shifted relative to each other along the axis of the beams, generates a low-light-intensity biconical region totally enclosed by the high-intensity light at the surface of the bicone, which is a type of bottle beam. Particles within this region are trapped by the photophoretic forces that push particles toward the low-intensity center of this region. Raman spectra from individual trapped particles made from carbon nanotubes are measured. This trapping technique could lead to the development of an on-line real-time single-particle Raman spectrometer for characterization of absorbing aerosol particles.

C-point and V-point singularity lattice formation and index sign conversion methods

NASA Astrophysics Data System (ADS)

Kumar Pal, Sushanta; Ruchi; Senthilkumaran, P.

2017-06-01

The generic singularities in an ellipse field are C-points namely stars, lemons and monstars in a polarization distribution with C-point indices (-1/2), (+1/2) and (+1/2) respectively. Similar to C-point singularities, there are V-point singularities that occur in a vector field and are characterized by Poincare-Hopf index of integer values. In this paper we show that the superposition of three homogenously polarized beams in different linear states leads to the formation of polarization singularity lattice. Three point sources at the focal plane of the lens are used to create three interfering plane waves. A radial/azimuthal polarization converter (S-wave plate) placed near the focal plane modulates the polarization states of the three beams. The interference pattern is found to host C-points and V-points in a hexagonal lattice. The C-points occur at intensity maxima and V-points occur at intensity minima. Modulating the state of polarization (SOP) of three plane waves from radial to azimuthal does not essentially change the nature of polarization singularity lattice as the Poincare-Hopf index for both radial and azimuthal polarization distributions is (+1). Hence a transformation from a star to a lemon is not trivial, as such a transformation requires not a single SOP change, but a change in whole spatial SOP distribution. Further there is no change in the lattice structure and the C- and V-points appear at locations where they were present earlier. Hence to convert an interlacing star and V-point lattice into an interlacing lemon and V-point lattice, the interferometer requires modification. We show for the first time a method to change the polarity of C-point and V-point indices. This means that lemons can be converted into stars and stars can be converted into lemons. Similarly the positive V-point can be converted to negative V-point and vice versa. The intensity distribution in all these lattices is invariant as the SOPs of the three beams are changed in an orderly fashion. It shows degeneracy as long as the SOPs of the three beams are drawn from polarization distributions that have Poincare-Hopf index of same magnitude. Various topological aspects of these lattices are presented with the help of Stokes field S12, which is constructed using generalized Stokes parameters of a fully polarized light. We envisage that such polarization lattice structure may lead to novel concept of structured polarization illumination methods in super resolution microscopy.

Using avian focal species to inform rangeland management in California oak woodland

Treesearch

Alicia D. Young; Breanna Owens; Melissa Odell; Corey Shake; Wendell Gilgert; Geoffrey R. Geupel

2015-01-01

Biological knowledge about bird focal species may be used to inform planning, habitat management, and restoration efforts, with the assumption that the implementation of these species-based recommendations will maintain and enhance healthy functioning habitats and the ecosystems services they provide. Point Blue Conservation Science in collaboration with the Natural...

Thermal Effects on Camera Focal Length in Messenger Star Calibration and Orbital Imaging

NASA Astrophysics Data System (ADS)

Burmeister, S.; Elgner, S.; Preusker, F.; Stark, A.; Oberst, J.

2018-04-01

We analyse images taken by the MErcury Surface, Space ENviorment, GEochemistry, and Ranging (MESSENGER) spacecraft for the camera's thermal response in the harsh thermal environment near Mercury. Specifically, we study thermally induced variations in focal length of the Mercury Dual Imaging System (MDIS). Within the several hundreds of images of star fields, the Wide Angle Camera (WAC) typically captures up to 250 stars in one frame of the panchromatic channel. We measure star positions and relate these to the known star coordinates taken from the Tycho-2 catalogue. We solve for camera pointing, the focal length parameter and two non-symmetrical distortion parameters for each image. Using data from the temperature sensors on the camera focal plane we model a linear focal length function in the form of f(T) = A0 + A1 T. Next, we use images from MESSENGER's orbital mapping mission. We deal with large image blocks, typically used for the production of a high-resolution digital terrain models (DTM). We analyzed images from the combined quadrangles H03 and H07, a selected region, covered by approx. 10,600 images, in which we identified about 83,900 tiepoints. Using bundle block adjustments, we solved for the unknown coordinates of the control points, the pointing of the camera - as well as the camera's focal length. We then fit the above linear function with respect to the focal plane temperature. As a result, we find a complex response of the camera to thermal conditions of the spacecraft. To first order, we see a linear increase by approx. 0.0107 mm per degree temperature for the Narrow-Angle Camera (NAC). This is in agreement with the observed thermal response seen in images of the panchromatic channel of the WAC. Unfortunately, further comparisons of results from the two methods, both of which use different portions of the available image data, are limited. If leaving uncorrected, these effects may pose significant difficulties in the photogrammetric analysis, specifically these may be responsible for erroneous longwavelength trends in topographic models.

Four Single-Page Learning Models.

ERIC Educational Resources Information Center

Hlynka, Denis

1979-01-01

Identifies four models of single-page learning systems that can streamline lengthy, complex prose: Information Mapping, Focal Press Model, Behavioral Objectives Model, and School Mathematics Model. (CMV)

Raman Spectroscopy of Single Light-Absorbing Carbonaceous Particles Levitated in Air Using an Annular Laser Beam.

PubMed

Uraoka, Masaru; Maegawa, Keisuke; Ishizaka, Shoji

2017-12-05

A laser trapping technique is a powerful means to investigate the physical and chemical properties of single aerosol particles in a noncontact manner. However, optical trapping of strongly light-absorbing particles such as black carbon or soot is quite difficult because the repulsive force caused by heat is orders of magnitude larger than the attractive force of radiation pressure. In this study, a laser trapping and Raman microspectroscopy system using an annular laser beam was constructed to achieve noncontact levitation of single light-absorbing particles in air. Single acetylene carbon black or candle soot particles were arbitrarily selected with a glass capillary connected to a three-axis oil hydraulic micromanipulator and introduced into a minute space surrounded by a repulsive force at the focal point of an objective lens. Using the developed system, we achieved optical levitation of micrometer-sized carbonaceous particles and observation of their Raman spectra in air. Furthermore, we demonstrated in situ observations of changes in the morphology and chemical composition of optically trapped carbonaceous particles in air, which were induced by heterogeneous oxidation reactions with ozone and hydroxyl radicals.

Taxonomy of multi-focal nematode image stacks by a CNN based image fusion approach.

PubMed

Liu, Min; Wang, Xueping; Zhang, Hongzhong

2018-03-01

In the biomedical field, digital multi-focal images are very important for documentation and communication of specimen data, because the morphological information for a transparent specimen can be captured in form of a stack of high-quality images. Given biomedical image stacks containing multi-focal images, how to efficiently extract effective features from all layers to classify the image stacks is still an open question. We present to use a deep convolutional neural network (CNN) image fusion based multilinear approach for the taxonomy of multi-focal image stacks. A deep CNN based image fusion technique is used to combine relevant information of multi-focal images within a given image stack into a single image, which is more informative and complete than any single image in the given stack. Besides, multi-focal images within a stack are fused along 3 orthogonal directions, and multiple features extracted from the fused images along different directions are combined by canonical correlation analysis (CCA). Because multi-focal image stacks represent the effect of different factors - texture, shape, different instances within the same class and different classes of objects, we embed the deep CNN based image fusion method within a multilinear framework to propose an image fusion based multilinear classifier. The experimental results on nematode multi-focal image stacks demonstrated that the deep CNN image fusion based multilinear classifier can reach a higher classification rate (95.7%) than that by the previous multilinear based approach (88.7%), even we only use the texture feature instead of the combination of texture and shape features as in the previous work. The proposed deep CNN image fusion based multilinear approach shows great potential in building an automated nematode taxonomy system for nematologists. It is effective to classify multi-focal image stacks. Copyright © 2018 Elsevier B.V. All rights reserved.

Focal Cryotherapy for Localized Prostate Cancer.

PubMed

Tay, K J; Polascik, T J

2016-07-01

To systematically review the oncological and functional outcomes of contemporary primary prostate focal cryotherapy for localized prostate cancer in the context of current developments in prostate focal therapy. We performed a systematic search of the Pubmed, Cochrane and Embase databases to identify studies where primary prostate focal cryotherapy was performed to treat prostate cancer. These included reports on focal/ lesion/ sector ablation, hemi-ablation and partial prostate ablation. We excluded salvage focal therapy studies. Where multiple reports were published over time from a single cohort, the latest one was used. Our search yielded 290 publications, including 17 primary reports on eight single-center cohort studies and one multi-center registry report. Of 1,595 men identified, mean age was 60.5-69.5 years and mean PSA 5.1-7.8 ng/ml. When stratified by D'Amico risk criteria, 52% of the aggregate total number of men were low-risk, 38% intermediate-risk and 10% high-risk. Besides 12-core TRUS biopsy, 3 cohorts reported using TTMB and one included mpMRI to select men for focal treatment. Median follow-up ranged from 13-63 months. BPFS ranged from 71-98%. The overall post-treatment positive biopsy rate was 8-25%. Among 5 cohorts with a mandatory 6-12 month posttreatment biopsy, 216 of 272 men (79%) did undergo biopsy, with 47 positive (21.8%). Of these, 15 were infield, 26 outfield, 2 bilateral and 4 undeclared. Ten upgraded to Gleason≥7. Overall, two men had metastatic disease and none died of prostate cancer. Post-treatment continence rates were 96-100% and rates of erectile dysfunction ranged from 0-42%. The rate of post-treatment urinary retention ranged from 0-15%. The rate of recto-urethral fistula was 0-0.1%. Focal cryotherapy for localized prostate cancer is a safe and provides good preservation of sexual and urinary function. Accurate cancer localization and risk stratification is key to patient selection. In highly selected patients, focal therapy has good short to medium term oncological efficacy.

47 CFR 215.0 - Purpose and authority.

Code of Federal Regulations, 2010 CFR

2010-10-01

... POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.0 Purpose and authority. The purpose of this part is to designate a focal point within the Federal Government for electromagnetic pulse (EMP...

47 CFR 215.0 - Purpose and authority.

Code of Federal Regulations, 2013 CFR

2013-10-01

... POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.0 Purpose and authority. The purpose of this part is to designate a focal point within the Federal Government for electromagnetic pulse (EMP...

47 CFR 215.0 - Purpose and authority.

Code of Federal Regulations, 2011 CFR

2011-10-01

... POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.0 Purpose and authority. The purpose of this part is to designate a focal point within the Federal Government for electromagnetic pulse (EMP...

47 CFR 215.0 - Purpose and authority.

Code of Federal Regulations, 2014 CFR

2014-10-01

... POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.0 Purpose and authority. The purpose of this part is to designate a focal point within the Federal Government for electromagnetic pulse (EMP...

47 CFR 215.0 - Purpose and authority.

Code of Federal Regulations, 2012 CFR

2012-10-01

... POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.0 Purpose and authority. The purpose of this part is to designate a focal point within the Federal Government for electromagnetic pulse (EMP...

An improved schlieren method for measurement and automatic reconstruction of the far-field focal spot

PubMed Central

Wang, Zhengzhou; Hu, Bingliang; Yin, Qinye

2017-01-01

The schlieren method of measuring far-field focal spots offers many advantages at the Shenguang III laser facility such as low cost and automatic laser-path collimation. However, current methods of far-field focal spot measurement often suffer from low precision and efficiency when the final focal spot is merged manually, thereby reducing the accuracy of reconstruction. In this paper, we introduce an improved schlieren method to construct the high dynamic-range image of far-field focal spots and improve the reconstruction accuracy and efficiency. First, a detection method based on weak light beam sampling and magnification imaging was designed; images of the main and side lobes of the focused laser irradiance in the far field were obtained using two scientific CCD cameras. Second, using a self-correlation template matching algorithm, a circle the same size as the schlieren ball was dug from the main lobe cutting image and used to change the relative region of the main lobe cutting image within a 100×100 pixel region. The position that had the largest correlation coefficient between the side lobe cutting image and the main lobe cutting image when a circle was dug was identified as the best matching point. Finally, the least squares method was used to fit the center of the side lobe schlieren small ball, and the error was less than 1 pixel. The experimental results show that this method enables the accurate, high-dynamic-range measurement of a far-field focal spot and automatic image reconstruction. Because the best matching point is obtained through image processing rather than traditional reconstruction methods based on manual splicing, this method is less sensitive to the efficiency of focal-spot reconstruction and thus offers better experimental precision. PMID:28207758

DEPDC5 takes a second hit in familial focal epilepsy.

PubMed

Anderson, Matthew P

2018-04-30

Loss-of-function mutations in a single allele of the gene encoding DEP domain-containing 5 protein (DEPDC5) are commonly linked to familial focal epilepsy with variable foci; however, a subset of patients presents with focal cortical dysplasia that is proposed to result from a second-hit somatic mutation. In this issue of the JCI, Ribierre and colleagues provide several lines of evidence to support second-hit DEPDC5 mutations in this disorder. Moreover, the authors use in vivo, in utero electroporation combined with CRISPR-Cas9 technology to generate a murine model of the disease that recapitulates human manifestations, including cortical dysplasia-like changes, focal seizures, and sudden unexpected death. This study provides important insights into familial focal epilepsy and provides a preclinical model for evaluating potential therapies.

Single image non-uniformity correction using compressive sensing

NASA Astrophysics Data System (ADS)

Jian, Xian-zhong; Lu, Rui-zhi; Guo, Qiang; Wang, Gui-pu

2016-05-01

A non-uniformity correction (NUC) method for an infrared focal plane array imaging system was proposed. The algorithm, based on compressive sensing (CS) of single image, overcame the disadvantages of "ghost artifacts" and bulk calculating costs in traditional NUC algorithms. A point-sampling matrix was designed to validate the measurements of CS on the time domain. The measurements were corrected using the midway infrared equalization algorithm, and the missing pixels were solved with the regularized orthogonal matching pursuit algorithm. Experimental results showed that the proposed method can reconstruct the entire image with only 25% pixels. A small difference was found between the correction results using 100% pixels and the reconstruction results using 40% pixels. Evaluation of the proposed method on the basis of the root-mean-square error, peak signal-to-noise ratio, and roughness index (ρ) proved the method to be robust and highly applicable.

Focal Adhesion Induction at the Tip of a Functionalized Nanoelectrode

PubMed Central

Fuentes, Daniela E.; Bae, Chilman; Butler, Peter J.

2012-01-01

Cells dynamically interact with their physical micro-environment through the assembly of nascent focal contacts and focal adhesions. The dynamics and mechanics of these contact points are controlled by transmembrane integrins and an array of intracellular adaptor proteins. In order to study the mechanics and dynamics of focal adhesion assembly, we have developed a technique for the timed induction of a nascent focal adhesion. Bovine aortic endothelial cells were approached at the apical surface by a nanoelectrode whose position was controlled with a resolution of 10s of nanometers using changes in electrode current to monitor distance from the cell surface. Since this probe was functionalized with fibronectin, a focal contact formed at the contact location. Nascent focal adhesion assembly was confirmed using time-lapse confocal fluorescent images of red fluorescent protein (RFP) – tagged talin, an adapter protein that binds to activated integrins. Binding to the cell was verified by noting a lack of change of electrode current upon retraction of the electrode. This study demonstrates that functionalized nanoelectrodes can enable precisely-timed induction and 3-D mechanical manipulation of focal adhesions and the assay of the detailed molecular kinetics of their assembly. PMID:22247742

Limit cycles in piecewise-affine gene network models with multiple interaction loops

NASA Astrophysics Data System (ADS)

Farcot, Etienne; Gouzé, Jean-Luc

2010-01-01

In this article, we consider piecewise affine differential equations modelling gene networks. We work with arbitrary decay rates, and under a local hypothesis expressed as an alignment condition of successive focal points. The interaction graph of the system may be rather complex (multiple intricate loops of any sign, multiple thresholds, etc.). Our main result is an alternative theorem showing that if a sequence of region is periodically visited by trajectories, then under our hypotheses, there exists either a unique stable periodic solution, or the origin attracts all trajectories in this sequence of regions. This result extends greatly our previous work on a single negative feedback loop. We give several examples and simulations illustrating different cases.

Radiation-Induced Transient Effects in Near Infrared Focal Plane Arrays

NASA Technical Reports Server (NTRS)

Reed, Robert A.; Pickel, J.; Marshall, P.; Waczynski, A.; McMurray, R.; Gee, G.; Polidan, E.; Johnson, S.; McKeivey, M.; Ennico, K.;

Improvements of the Ray-Tracing Based Method Calculating Hypocentral Loci for Earthquake Location

NASA Astrophysics Data System (ADS)

Zhao, A. H.

2014-12-01

Hypocentral loci are very useful to reliable and visual earthquake location. However, they can hardly be analytically expressed when the velocity model is complex. One of methods numerically calculating them is based on a minimum traveltime tree algorithm for tracing rays: a focal locus is represented in terms of ray paths in its residual field from the minimum point (namely initial point) to low residual points (referred as reference points of the focal locus). The method has no restrictions on the complexity of the velocity model but still lacks the ability of correctly dealing with multi-segment loci. Additionally, it is rather laborious to set calculation parameters for obtaining loci with satisfying completeness and fineness. In this study, we improve the ray-tracing based numerical method to overcome its advantages. (1) Reference points of a hypocentral locus are selected from nodes of the model cells that it goes through, by means of a so-called peeling method. (2) The calculation domain of a hypocentral locus is defined as such a low residual area that its connected regions each include one segment of the locus and hence all the focal locus segments are respectively calculated with the minimum traveltime tree algorithm for tracing rays by repeatedly assigning the minimum residual reference point among those that have not been traced as an initial point. (3) Short ray paths without branching are removed to make the calculated locus finer. Numerical tests show that the improved method becomes capable of efficiently calculating complete and fine hypocentral loci of earthquakes in a complex model.

Myofascial trigger points: spontaneous electrical activity and its consequences for pain induction and propagation

PubMed Central

2011-01-01

Active myofascial trigger points are one of the major peripheral pain generators for regional and generalized musculoskeletal pain conditions. Myofascial trigger points are also the targets for acupuncture and/or dry needling therapies. Recent evidence in the understanding of the pathophysiology of myofascial trigger points supports The Integrated Hypothesis for the trigger point formation; however unanswered questions remain. Current evidence shows that spontaneous electrical activity at myofascial trigger point originates from the extrafusal motor endplate. The spontaneous electrical activity represents focal muscle fiber contraction and/or muscle cramp potentials depending on trigger point sensitivity. Local pain and tenderness at myofascial trigger points are largely due to nociceptor sensitization with a lesser contribution from non-nociceptor sensitization. Nociceptor and non-nociceptor sensitization at myofascial trigger points may be part of the process of muscle ischemia associated with sustained focal muscle contraction and/or muscle cramps. Referred pain is dependent on the sensitivity of myofascial trigger points. Active myofascial trigger points may play an important role in the transition from localized pain to generalized pain conditions via the enhanced central sensitization, decreased descending inhibition and dysfunctional motor control strategy. PMID:21439050

Design and evaluation of a grid reciprocation scheme for use in digital breast tomosynthesis

NASA Astrophysics Data System (ADS)

Patel, Tushita; Sporkin, Helen; Peppard, Heather; Williams, Mark B.

2016-03-01

This work describes a methodology for efficient removal of scatter radiation during digital breast tomosynthesis (DBT). The goal of this approach is to enable grid image obscuration without a large increase in radiation dose by minimizing misalignment of the grid focal point (GFP) and x-ray focal spot (XFS) during grid reciprocation. Hardware for the motion scheme was built and tested on the dual modality breast tomosynthesis (DMT) scanner, which combines DBT and molecular breast tomosynthesis (MBT) on a single gantry. The DMT scanner uses fully isocentric rotation of tube and x-ray detector for maintaining a fixed tube-detector alignment during DBT imaging. A cellular focused copper prototype grid with 80 cm focal length, 3.85 mm height, 0.1 mm thick lamellae, and 1.1 mm hole pitch was tested. Primary transmission of the grid at 28 kV tube voltage was on average 74% with the grid stationary and aligned for maximum transmission. It fell to 72% during grid reciprocation by the proposed method. Residual grid line artifacts (GLAs) in projection views and reconstructed DBT images are characterized and methods for reducing the visibility of GLAs in the reconstructed volume through projection image flat-field correction and spatial frequency-based filtering of the DBT slices are described and evaluated. The software correction methods reduce the visibility of these artifacts in the reconstructed volume, making them imperceptible both in the reconstructed DBT images and their Fourier transforms.

Motor training reduces surround inhibition in the motor cortex.

PubMed

Akkad, Haya; Di Stasio, Flavio; Tibold, Robert; Kassavetis, Panagiotis; Rothwell, John C; Edwards, Mark J

2016-06-01

Surround inhibition (SI) is thought to facilitate focal contraction of a hand muscle by keeping nearby muscles silent. Unexpectedly, SI is reduced in skilled pianists. We tested whether repeated practice of focal contraction in non-pianists could reduce SI. Motor-evoked potentials were elicited by transcranial magnetic stimulation in the relaxed abductor digiti minimi randomly at the onset and 5s after offset of a 2s focal contraction (10% maximum) of the first dorsal interosseous (FDI). Over 5 blocks of 40 trials participants obtained points for increasing contraction speed and stability in FDI. In a final block, the interval between contractions was varied randomly to increase attention to the task. Over the first 5 blocks, SI declined as performance (points scored) improved. In the final "attention" block SI increased towards baseline without affecting performance. Although SI may be useful during the early stages of learning, skilled focal finger movement does not require SI to prevent activity in non-involved muscles. This could be due to better targeting of the excitatory command to move. Results from the final block suggest that increased attention can re-engage SI when task parameters change. SI is not necessary for successful focal contraction, but may contribute during learning and during attention to task. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

X-ray focal spot reconstruction by circular penumbra analysis-Application to digital radiography systems.

PubMed

Di Domenico, Giovanni; Cardarelli, Paolo; Contillo, Adriano; Taibi, Angelo; Gambaccini, Mauro

2016-01-01

The quality of a radiography system is affected by several factors, a major one being the focal spot size of the x-ray tube. In fact, the measurement of such size is recognized to be of primary importance during acceptance tests and image quality evaluations of clinical radiography systems. The most common device providing an image of the focal spot emission distribution is a pin-hole camera, which requires a high tube loading in order to produce a measurable signal. This work introduces an alternative technique to obtain an image of the focal spot, through the processing of a single radiograph of a simple test object, acquired with a suitable magnification. The radiograph of a magnified sharp edge is a well-established method to evaluate the extension of the focal spot profile along the direction perpendicular to the edge. From a single radiograph of a circular x-ray absorber, it is possible to extract simultaneously the radial profiles of several sharp edges with different orientations. The authors propose a technique that allows to obtain an image of the focal spot through the processing of these radial profiles by means of a pseudo-CT reconstruction technique. In order to validate this technique, the reconstruction has been applied to the simulated radiographs of an ideal disk-shaped absorber, generated by various simulated focal spot distributions. Furthermore, the method has been applied to the focal spot of a commercially available mammography unit. In the case of simulated radiographs, the results of the reconstructions have been compared to the original distributions, showing an excellent agreement for what regards both the overall distribution and the full width at half maximum measurements. In the case of the experimental test, the method allowed to obtain images of the focal spot that have been compared with the results obtained through standard techniques, namely, pin-hole camera and slit camera. The method was proven to be effective for simulated images and the results of the experimental test suggest that it could be considered as an alternative technique for focal spot distribution evaluation. The method offers the possibility to measure the actual focal spot size and emission distribution at the same exposure conditions as clinical routine, avoiding high tube loading as in the case of the pin-hole imaging technique.

Analysis of the intraocular jet flows and pressure gradients induced by air and fluid infusion: mechanism of focal chorioretinal damage.

PubMed

Kim, Yong Joon; Jo, Sungkil; Moon, Daruchi; Joo, Youngcheol; Choi, Kyung Seek

2014-05-01

To comprehend the mechanism of focal chorioretinal damage by analysis of the pressure distribution and dynamic pressure induced by infused air during fluid-air exchange. A precise simulation featuring a model eye and a fluid circuit was designed to analyze fluid-air exchange. The pressure distribution, flow velocity, and dynamic pressure induced by infusion of air into an air-filled eye were analyzed using an approach based on fluid dynamics. The size of the port and the infusion pressure were varied during simulated iterations. We simulated infusion of an air-filled eye with balanced salt solution (BSS) to better understand the mechanism of chorioretinal damage induced by infused air. Infused air was projected straight toward a point on the retina contralateral to the infusion port (the "vulnerable point"). The highest pressure was evident at the vulnerable point, and the lowest pressure was recorded on most retinal areas. Simulations using greater infusion pressure and a port of larger size were associated with elevations in dynamic pressure and the pressure gradient. The pressure gradients were 2.8 and 5.1 mm Hg, respectively, when infusion pressures of 30 and 50 mm Hg were delivered through a 20-gauge port. The pressure gradient associated with BSS infusion was greater than that created by air, but lasted for only a moment. Our simulation explains the mechanism of focal chorioretinal damage in numerical terms. Infused air induces a prolonged increase in focal pressure on the vulnerable point, and this may be responsible for visual field defects arising after fluid-air exchange. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

Focus collimator press for a collimator for gamma ray cameras

DOE Office of Scientific and Technical Information (OSTI.GOV)

York, R.N.; York, D.L.

A focus collimator press for collimators for gamma ray cameras is described comprising a pivot arm of fixed length mounted on a travelling pivot which is movable in the plane of a spaced apart work table surface in a direction toward and away from the work table. A press plate is carried at the opposite end of the fixed length pivot arm, and is maintained in registration with the same portion of the work table for pressing engagement with each undulating radiation opaque strip as it is added to the top of a collimator stack in process by movement ofmore » the travelling pivot inward toward the work table. This enables the press plate to maintain its relative position above the collimator stack and at the same time the angle of the press plate changes, becoming less acute in relation to the work table as the travelling pivot motes inwardly toward the work table. The fixed length of the pivot arm is substantially equal to the focal point of the converging apertures formed by each pair of undulating strips stacked together. Thus, the focal point of each aperture row falls substantially on the axis of the travelling pivot, and since it moves in the plane of the work table surface the focal point of each aperture row is directed to lie in the same common plane. When one of two collimator stacks made in this way is rotated 180 degrees and the two bonded together along their respective first strips, all focal points of every aperture row lie on the central axis of the completed collimator.« less

[Adipose-derived stem cell transplantation promotes the expression of netrin-1 in the rat cortex after focal cerebral ischemia].

PubMed

Wang, Jiehua; Hong, Zhuquan; Pan, Ying; Li, Guoqian

2017-01-01

Objective To observe the effect of adipose-derived stem cells (ADSCs) transplantation on the expression of netrin-1 in rats after focal cerebral ischemia. Methods Male SD rats were randomly divided into control group, model group and ADSC group. ADSCs were harvested and purified. Focal cerebral ischemia models were established in rats by the suture method. ADSCs were injected into the lateral ventricle of ADSC group rats and the same does of PBS was given to model group rats. At day 4, 7 and 14 after reperfusion, six rats were sacrificed to remove the brain tissues at each time point. The expression of netrin-1 was detected by reverse-transcription PCR, Western blotting and immunohistochemistry. Results Compared with the control group, the expression of netrin-1 in the brain tissues of the model group increased after focal cerebral ischemia, reached the peak at 4 days, and the expression of netrin-1 was significantly higher than that of the control group at each time point. Compared with the model group, the expression of netrin-1 in the ADSC group increased further, reached the peak at 7 days, and the expression of netrin-1 in the ADSC group was significantly higher than that of the model group at each time point. Conclusion ADSC transplantation could up-regulate the expression of netrin-1, and promote axon regeneration and the recovery of neurological functions.

Describing the genetic architecture of epilepsy through heritability analysis.

PubMed

Speed, Doug; O'Brien, Terence J; Palotie, Aarno; Shkura, Kirill; Marson, Anthony G; Balding, David J; Johnson, Michael R

2014-10-01

Epilepsy is a disease with substantial missing heritability; despite its high genetic component, genetic association studies have had limited success detecting common variants which influence susceptibility. In this paper, we reassess the role of common variants on epilepsy using extensions of heritability analysis. Our data set consists of 1258 UK patients with epilepsy, of which 958 have focal epilepsy, and 5129 population control subjects, with genotypes recorded for over 4 million common single nucleotide polymorphisms. Firstly, we show that on the liability scale, common variants collectively explain at least 26% (standard deviation 5%) of phenotypic variation for all epilepsy and 27% (standard deviation 5%) for focal epilepsy. Secondly we provide a new method for estimating the number of causal variants for complex traits; when applied to epilepsy, our most optimistic estimate suggests that at least 400 variants influence disease susceptibility, with potentially many thousands. Thirdly, we use bivariate analysis to assess how similar the genetic architecture of focal epilepsy is to that of non-focal epilepsy; we demonstrate both significant differences (P = 0.004) and significant similarities (P = 0.01) between the two subtypes, indicating that although the clinical definition of focal epilepsy does identify a genetically distinct epilepsy subtype, there is also scope to improve the classification of epilepsy by incorporating genotypic information. Lastly, we investigate the potential value in using genetic data to diagnose epilepsy following a single epileptic seizure; we find that a prediction model explaining 10% of phenotypic variation could have clinical utility for deciding which single-seizure individuals are likely to benefit from immediate anti-epileptic drug therapy. © The Author (2014). Published by Oxford University Press on behalf of the Guarantors of Brain.

Cigarette Ads and Youth.

ERIC Educational Resources Information Center

Carol, Julia

1988-01-01

Points out ways the tobacco industry markets products to youth, including paid advertisements, sponsorship of sporting events, music concerts, and magazines. Relates several focal points for smoking prevention, which include deglamorization of cigarette advertisements and making smoking socially undesirable. (LS)

Method and apparatus for aligning a solar concentrator using two lasers

DOEpatents

Diver Jr., Richard Boyer

2003-07-22

A method and apparatus are provided for aligning the facets of a solar concentrator. A first laser directs a first laser beam onto a selected facet of the concentrator such that a target board positioned adjacent to the first laser at approximately one focal length behind the focal point of the concentrator is illuminated by the beam after reflection thereof off of the selected facet. A second laser, located adjacent to the vertex of the optical axis of the concentrator, is used to direct a second laser beam onto the target board at a target point thereon. By adjusting the selected facet to cause the first beam to illuminate the target point on the target board produced by the second beam, the selected facet can be brought into alignment with the target point. These steps are repeated for other selected facets of the concentrator, as necessary, to provide overall alignment of the concentrator.

Distortion of Dynamical Systems in the Context of Focusing the Chaos Around the Point

NASA Astrophysics Data System (ADS)

Pawlak, Ryszard J.

In the paper, we examine local aspects of chaos for self-functions on topological manifolds. For this purpose, issues related to focal entropy points and homoclinic points are used. We consider also distortion of dynamical systems which is a theoretical analogue to wave interference.

Update on the Use of Botulinum Toxin Therapy for Focal and Task-Specific Dystonias.

PubMed

Lungu, Codrin; Ahmad, Omar F

2016-02-01

Focal dystonia is defined by anatomical distribution and represents a distinct entity from generalized dystonia. Task-specific dystonia occurs in the context of specific patterns of movement. Botulinum neurotoxin (BoNT) injections are the treatment of choice in most cases. Several formulations are available; the approved indications, dosing, and some administration details, differ between them. The major forms of focal and task-specific dystonia are reviewed, along with the evidence for BoNT therapy, the expected benefit and side effects, and practical points guiding the injections. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Fusion of light-field and photogrammetric surface form data

NASA Astrophysics Data System (ADS)

Sims-Waterhouse, Danny; Piano, Samanta; Leach, Richard K.

2017-08-01

Photogrammetry based systems are able to produce 3D reconstructions of an object given a set of images taken from different orientations. In this paper, we implement a light-field camera within a photogrammetry system in order to capture additional depth information, as well as the photogrammetric point cloud. Compared to a traditional camera that only captures the intensity of the incident light, a light-field camera also provides angular information for each pixel. In principle, this additional information allows 2D images to be reconstructed at a given focal plane, and hence a depth map can be computed. Through the fusion of light-field and photogrammetric data, we show that it is possible to improve the measurement uncertainty of a millimetre scale 3D object, compared to that from the individual systems. By imaging a series of test artefacts from various positions, individual point clouds were produced from depth-map information and triangulation of corresponding features between images. Using both measurements, data fusion methods were implemented in order to provide a single point cloud with reduced measurement uncertainty.

Focal myositis of lower extremity responsive to botulinum A toxin.

PubMed

Mitrovic, Josko; Prka, Zeljko; Zic, Rado; Marusic, Srecko; Morovic-Vergles, Jadranka

2014-01-01

Focal myositis is a rare, mostly benign disease (pseudotumor) of skeletal muscle, histopathologically characterized by interstitial myositis and tumorous enlargement of a single muscle. The etiology of focal myositis remains unknown; however, localized myopathy has been postulated to be caused by denervation lesions. This case report describes a patient that presented with clinical, laboratory, electromyoneurography, and magnetic resonance imaging features of focal myositis complicated with intervertebral disk protrusion in the lumbosacral spine affected with radicular distress. In most cases, focal myositic lesions show spontaneous regression, relapses are rare, and long-term prognosis is good. There is a wide spectrum of therapeutic options, from no therapy at all through nonsteroidal antirheumatics and glucocorticoids to radiotherapy, surgical excision, and immunosuppressants. In the patient presented, treatment with glucocorticoids, methotrexate, and surgical excision failed to produce satisfactory results. Clinical improvement, pain relief, and reduction in lower leg volume were only achieved by local infiltration of botulinum A toxin.

Silhouettes - An automated three-dimensional plume visualization and tracking system for environmental monitoring

NASA Technical Reports Server (NTRS)

Cambridge, Vivien J.; Magee, Ronald G.

1993-01-01

The method of silhouettes proceeds from the premise that the 3D location and shape of an arbitrary object can be approximated via the cross section of a series of conical volumes whose focal points are arranged at sites surrounding the object; the projection of each conical volume onto a picture plane at each focal point is identical to a projection of the outline of the object onto that picture plane. Attention is presently given to the use of the silhouettes method for gas plume dispersion monitoring through the 3D reconstruction of plumes from imagery acquired at strategically located stations in the plumes' path.

Solar Thermal Propulsion Test

NASA Technical Reports Server (NTRS)

1999-01-01

Researchers at the Marshall Space Flight Center (MSFC) have designed, fabricated, and tested the first solar thermal engine, a non-chemical rocket engine that produces lower thrust but has better thrust efficiency than a chemical combustion engine. MSFC turned to solar thermal propulsion in the early 1990s due to its simplicity, safety, low cost, and commonality with other propulsion systems. Solar thermal propulsion works by acquiring and redirecting solar energy to heat a propellant. The 20- by 24-ft heliostat mirror (not shown in this photograph) has a dual-axis control that keeps a reflection of the sunlight on the 18-ft diameter concentrator mirror, which then focuses the sunlight to a 4-in focal point inside the vacuum chamber. The focal point has 10 kilowatts of intense solar power. This image, taken during the test, depicts the light being concentrated into the focal point inside the vacuum chamber. As part of MSFC's Space Transportation Directorate, the Propulsion Research Center serves as a national resource for research of advanced, revolutionary propulsion technologies. The mission is to move the Nation's capabilities beyond the confines of conventional chemical propulsion into an era of aircraft-like access to Earth orbit, rapid travel throughout the solar system, and exploration of interstellar space.

Research Technology

NASA Image and Video Library

1999-03-01

Researchers at the Marshall Space Flight Center (MSFC) have designed, fabricated, and tested the first solar thermal engine, a non-chemical rocket engine that produces lower thrust but has better thrust efficiency than a chemical combustion engine. MSFC turned to solar thermal propulsion in the early 1990s due to its simplicity, safety, low cost, and commonality with other propulsion systems. Solar thermal propulsion works by acquiring and redirecting solar energy to heat a propellant. The 20- by 24-ft heliostat mirror (not shown in this photograph) has a dual-axis control that keeps a reflection of the sunlight on the 18-ft diameter concentrator mirror, which then focuses the sunlight to a 4-in focal point inside the vacuum chamber. The focal point has 10 kilowatts of intense solar power. This image, taken during the test, depicts the light being concentrated into the focal point inside the vacuum chamber. As part of MSFC's Space Transportation Directorate, the Propulsion Research Center serves as a national resource for research of advanced, revolutionary propulsion technologies. The mission is to move the Nation's capabilities beyond the confines of conventional chemical propulsion into an era of aircraft-like access to Earth orbit, rapid travel throughout the solar system, and exploration of interstellar space.

The effect of standing acoustic waves on the formation of laser-induced air plasmas.

PubMed

Craig, Stephanie M; Brownell, Kara; O'Leary, Brendon; Malfitano, Christopher; Kelley, Jude A

2013-03-01

The expected location of an air plasma produced by a focused YAG laser pulse has been found to be influenced by the acoustics of the surrounding environment. In open air, the expected location of a laser-induced air plasma is centered close to the focal point of the lens focusing the laser beam. When confining the same beam coaxially along the interior of a quartz tube, the expected location of the air plasma shifts away from the focal point, toward the focusing lens, in a region of less laser fluence. This shift is caused by an interaction between standing acoustic waves (formed from sound waves produced by previous laser-induced plasmas) and the impinging laser pulse. Standing acoustic waves in a tube produce areas (antinodes) of slightly higher and slightly lower pressure than ambient atmospheric conditions, that in turn have a noticeable affect on the probability of creating an air plasma at a given location. This leads to two observed phenomena: Increased probability of air plasma formation before the optical focal point is reached, and the formation of distinct (separate) air plasmas at the antinodes themselves.

Development and performance evaluation of an electromagnetic-type shock wave generator for lipolysis.

PubMed

Liang, S M; Chang, M H; Yang, Z Y

2014-01-01

This study aims at the design and development of electromagnetic-type intermittent shock wave generation in a liquid. The shock wave generated is focused at a focal point through an acoustic lens. This hardware device mainly consists of a full-wave bridge rectifier, 6 capacitors, a spark gap, and a flat coil. A metal disk is mounted in a liquid-filled tube and is placed in close proximity to the flat coil. Due to the repulsive force existing between the coil and disk shock waves are generated, while an eddy current is induced in the metal disk. Some components and materials associated with the device are also described. By increasing the capacitance content to enhance electric energy level, a highly focused pressure can be achieved at the focal point through an acoustic lens in order to lyse fat tissue. Focused pressures were measured at the focal point and its vicinity for different operation voltages. The designed shock wave generator with an energy intensity of 0.0016 mJ/mm(2) (at 4 kV) and 2000 firings or higher energy intensities with 1000 firings is found to be able to disrupt pig fat tissue.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liang, S. M., E-mail: liangsm@cc.feu.edu.tw; Yang, Z. Y.; Chang, M. H.

This study aims at the design and development of electromagnetic-type intermittent shock wave generation in a liquid. The shock wave generated is focused at a focal point through an acoustic lens. This hardware device mainly consists of a full-wave bridge rectifier, 6 capacitors, a spark gap, and a flat coil. A metal disk is mounted in a liquid-filled tube and is placed in close proximity to the flat coil. Due to the repulsive force existing between the coil and disk shock waves are generated, while an eddy current is induced in the metal disk. Some components and materials associated withmore » the device are also described. By increasing the capacitance content to enhance electric energy level, a highly focused pressure can be achieved at the focal point through an acoustic lens in order to lyse fat tissue. Focused pressures were measured at the focal point and its vicinity for different operation voltages. The designed shock wave generator with an energy intensity of 0.0016 mJ/mm{sup 2} (at 4 kV) and 2000 firings or higher energy intensities with 1000 firings is found to be able to disrupt pig fat tissue.« less

Butterfly Wings Are Three-Dimensional: Pupal Cuticle Focal Spots and Their Associated Structures in Junonia Butterflies.

PubMed

Taira, Wataru; Otaki, Joji M

2016-01-01

Butterfly wing color patterns often contain eyespots, which are developmentally determined at the late larval and early pupal stages by organizing activities of focal cells that can later form eyespot foci. In the pupal stage, the focal position of a future eyespot is often marked by a focal spot, one of the pupal cuticle spots, on the pupal surface. Here, we examined the possible relationships of the pupal focal spots with the underneath pupal wing tissues and with the adult wing eyespots using Junonia butterflies. Large pupal focal spots were found in two species with large adult eyespots, J. orithya and J. almana, whereas only small pupal focal spots were found in a species with small adult eyespots, J. hedonia. The size of five pupal focal spots on a single wing was correlated with the size of the corresponding adult eyespots in J. orithya. A pupal focal spot was a three-dimensional bulge of cuticle surface, and the underside of the major pupal focal spot exhibited a hollowed cuticle in a pupal case. Cross sections of a pupal wing revealed that the cuticle layer shows a curvature at a focal spot, and a positional correlation was observed between the cuticle layer thickness and its corresponding cell layer thickness. Adult major eyespots of J. orithya and J. almana exhibited surface elevations and depressions that approximately correspond to the coloration within an eyespot. Our results suggest that a pupal focal spot is produced by the organizing activity of focal cells underneath the focal spot. Probably because the focal cell layer immediately underneath a focal spot is thicker than that of its surrounding areas, eyespots of adult butterfly wings are three-dimensionally constructed. The color-height relationship in adult eyespots might have an implication in the developmental signaling for determining the eyespot color patterns.

Butterfly Wings Are Three-Dimensional: Pupal Cuticle Focal Spots and Their Associated Structures in Junonia Butterflies

PubMed Central

Taira, Wataru; Otaki, Joji M.

2016-01-01

Butterfly wing color patterns often contain eyespots, which are developmentally determined at the late larval and early pupal stages by organizing activities of focal cells that can later form eyespot foci. In the pupal stage, the focal position of a future eyespot is often marked by a focal spot, one of the pupal cuticle spots, on the pupal surface. Here, we examined the possible relationships of the pupal focal spots with the underneath pupal wing tissues and with the adult wing eyespots using Junonia butterflies. Large pupal focal spots were found in two species with large adult eyespots, J. orithya and J. almana, whereas only small pupal focal spots were found in a species with small adult eyespots, J. hedonia. The size of five pupal focal spots on a single wing was correlated with the size of the corresponding adult eyespots in J. orithya. A pupal focal spot was a three-dimensional bulge of cuticle surface, and the underside of the major pupal focal spot exhibited a hollowed cuticle in a pupal case. Cross sections of a pupal wing revealed that the cuticle layer shows a curvature at a focal spot, and a positional correlation was observed between the cuticle layer thickness and its corresponding cell layer thickness. Adult major eyespots of J. orithya and J. almana exhibited surface elevations and depressions that approximately correspond to the coloration within an eyespot. Our results suggest that a pupal focal spot is produced by the organizing activity of focal cells underneath the focal spot. Probably because the focal cell layer immediately underneath a focal spot is thicker than that of its surrounding areas, eyespots of adult butterfly wings are three-dimensionally constructed. The color-height relationship in adult eyespots might have an implication in the developmental signaling for determining the eyespot color patterns. PMID:26731532

The use of biomaterials for cell function enhancement: acceleration of fibroblast migration and promotion of stem cell proliferation

NASA Astrophysics Data System (ADS)

Qin, Sisi

Wound healing and tissue regeneration proceed via fibroblast migration along three dimensional scaffolds composed of fibers with different diameters, spacing, and junction angles. In order to understand how each of these factors influences fibroblast migration, a technique for preparation of three dimensional fibrillar scaffolds was developed where the fiber diameters and the angles between adjacent fiber layers could be precisely controlled. In order to study the en-mass migration process, the agarose droplet method was chosen since it enabled accurate determinations of the dependence of the migration speed, focal adhesion distribution, and nuclear deformation on the fiber structures. Results showed that on oriented single fiber layers, if the fiber diameters exceeded 1microm, large focal adhesion complexes formed in a linear arrangement along the fiber axis and cell motion was highly correlated. For fibers 1microm or less, some cell alignment along the fiber direction was measured, but no correlation between the distribution of focal adhesion points and fiber orientation was found. On multi layered scaffolds the focal adhesion sites were found to concentrate at the junction points and the migration speed followed a parabolic function with a distinct minimum at 35°. When compared to fibroblasts plated on 90° fibers, fibroblasts plated on 30° fibers showed a decrease of 25% in the degree of nuclear deformation and an increase of 25% in the number of focal adhesion sites, indicating that cell migration speed was correlated to the angle and distance of approach to the junction point. The time dependence of the migration velocity on oriented fibers was measured for four days and compared to the value measured on flat surfaces. After the initial 24 hour incubation period, the cells on both the 8microm fibers and flat surfaces migrated with a similar speed. During the next three days the migration speed for the cells on the fibrillar surfaces doubled in magnitude, while remained constant for the cells on the flat surfaces. The increased speed on the 8microm fiber surfaces could be correlated with a 20% increase in the nuclear deformation, and a decrease around 30% in the number of focal adhesion during the same observation period. RNA expression of Myosin IIA, a protein which complexes to the actin and is responsible for exertion of traction forces during migration was not upregulated during this process. On the other hand, histochemical staining of Myosin IIA showed that the protein had re-organized into large fibers which spanned the length of the cells. Observation of the cell morphology indicated that a new mode of motion had been established. Rather than the classical retraction of the cytoplasm followed by center of mass translation, which was observed on the flat surfaces, the cells were now moving by a contractile motion around the nucleus similar to that found in muscular motion. This mode was found to be more efficient when undergoing oriented motion. In addition to orientation, surface mechanics are also important in the tissue regeneration process. This study demonstrated that mechanical factors are important for the maintenance of pluripotency and control of proliferation rates. CD34+ hematopoietic stem cells (HSCs) were transduced with ICD (intracellular domain)-Notch and plated on gelatin hydrogels, whose moduli were controlled by the crosslinking ratio. On the softer hydrogel, a synergy was achieved which resulted in more than a five-fold increase in proliferation and a four-fold increase in the preservation of stemness, while HSCs maintained their ability to differentiate into multiple blood cell lineages. These results point the way for achieving clinically significant expansion of human HSCs.

Statistical earthquake focal mechanism forecasts

NASA Astrophysics Data System (ADS)

Kagan, Yan Y.; Jackson, David D.

2014-04-01

Forecasts of the focal mechanisms of future shallow (depth 0-70 km) earthquakes are important for seismic hazard estimates and Coulomb stress, and other models of earthquake occurrence. Here we report on a high-resolution global forecast of earthquake rate density as a function of location, magnitude and focal mechanism. In previous publications we reported forecasts of 0.5° spatial resolution, covering the latitude range from -75° to +75°, based on the Global Central Moment Tensor earthquake catalogue. In the new forecasts we have improved the spatial resolution to 0.1° and the latitude range from pole to pole. Our focal mechanism estimates require distance-weighted combinations of observed focal mechanisms within 1000 km of each gridpoint. Simultaneously, we calculate an average rotation angle between the forecasted mechanism and all the surrounding mechanisms, using the method of Kagan & Jackson proposed in 1994. This average angle reveals the level of tectonic complexity of a region and indicates the accuracy of the prediction. The procedure becomes problematical where longitude lines are not approximately parallel, and where shallow earthquakes are so sparse that an adequate sample spans very large distances. North or south of 75°, the azimuths of points 1000 km away may vary by about 35°. We solved this problem by calculating focal mechanisms on a plane tangent to the Earth's surface at each forecast point, correcting for the rotation of the longitude lines at the locations of earthquakes included in the averaging. The corrections are negligible between -30° and +30° latitude, but outside that band uncorrected rotations can be significantly off. Improved forecasts at 0.5° and 0.1° resolution are posted at http://eq.ess.ucla.edu/kagan/glob_gcmt_index.html.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Di Domenico, Giovanni, E-mail: didomenico@fe.infn.it; Cardarelli, Paolo; Taibi, Angelo

Purpose: The quality of a radiography system is affected by several factors, a major one being the focal spot size of the x-ray tube. In fact, the measurement of such size is recognized to be of primary importance during acceptance tests and image quality evaluations of clinical radiography systems. The most common device providing an image of the focal spot emission distribution is a pin-hole camera, which requires a high tube loading in order to produce a measurable signal. This work introduces an alternative technique to obtain an image of the focal spot, through the processing of a single radiographmore » of a simple test object, acquired with a suitable magnification. Methods: The radiograph of a magnified sharp edge is a well-established method to evaluate the extension of the focal spot profile along the direction perpendicular to the edge. From a single radiograph of a circular x-ray absorber, it is possible to extract simultaneously the radial profiles of several sharp edges with different orientations. The authors propose a technique that allows to obtain an image of the focal spot through the processing of these radial profiles by means of a pseudo-CT reconstruction technique. In order to validate this technique, the reconstruction has been applied to the simulated radiographs of an ideal disk-shaped absorber, generated by various simulated focal spot distributions. Furthermore, the method has been applied to the focal spot of a commercially available mammography unit. Results: In the case of simulated radiographs, the results of the reconstructions have been compared to the original distributions, showing an excellent agreement for what regards both the overall distribution and the full width at half maximum measurements. In the case of the experimental test, the method allowed to obtain images of the focal spot that have been compared with the results obtained through standard techniques, namely, pin-hole camera and slit camera. Conclusions: The method was proven to be effective for simulated images and the results of the experimental test suggest that it could be considered as an alternative technique for focal spot distribution evaluation. The method offers the possibility to measure the actual focal spot size and emission distribution at the same exposure conditions as clinical routine, avoiding high tube loading as in the case of the pin-hole imaging technique.« less

Truncation of the secondary concentrator (CPC) between maximum performances and economical requirements

NASA Astrophysics Data System (ADS)

Segal, A.; Epstein, M.

2009-08-01

A central solar plant, based on beam-down optics, is composed of a field of heliostats, a tower reflector and a ground receiver. The tower reflector is an optical system comprises of a quadric surface mirror (hyperboloid), where its upper focal point coincides with the aim point of a heliostat field and its lower focal point is located at a specified height, coinciding with the entrance plane of the ground receiver. The optics of a tower reflector requires the use of ground secondary concentrator, composed of a cluster of CPCs, because the quadric surface mirror always magnifies the sun image. There is an intrinsic correlation between the tower reflector position and its size on one hand, and the geometry, dimensions and reflective area of the secondary concentrator on the other hand; both are related to the heliostat field reflective area. Obviously, when one wishes to have a smaller tower reflector by placing it closer to the upper focal point, the image created at the lower focus will be larger, resulting in a larger secondary ground concentrator. The present work analyses the ways for a substantial decrease of the size of the ground concentrator cluster (and, implicit, the concentrators area) via truncation, without significant sacrifice of the performance, although some increase of the optical losses is inevitable. This offers a method for cost effective design of future central solar plants utilizing the beam down optics.

Status of Reconstruction of Fragmented Diamond-on-Silicon Collector From Genesis Spacecraft Solar Wind Concentrator

NASA Technical Reports Server (NTRS)

Rodriquez, Melissa C.; Calaway, M. C.; McNamara, K. M.; Hittle, J. D.

2009-01-01

In addition to passive solar wind collector surfaces, the Genesis Discovery Mission science canister had on board an electrostatic concave mirror for concentrating the solar wind ions, known as the concentrator . The 30-mm-radius collector focal point (the target) was comprised of 4 quadrants: two of single crystal SiC, one of polycrystalline 13C diamond and one of diamond-like-carbon (DLC) on a silicon substrate. [DLC-on-silicon is also sometimes referenced as Diamond-on-silicon, DOS.] Three of target quadrants survived the hard landing intact, but the DLC-on-silicon quadrant fractured into numerous pieces (Fig. 1). This abstract reports the status of identifying the DLC target fragments and reconstructing their original orientation.

[From assimilation to multiculturalism. Twenty years of policy and social research on immigration in Sweden (1966-1985)].

PubMed

Marta, C

1991-03-01

"The essay analyzes the immigration policy pursued by Sweden from 1966, the year in which the first commission was established for this particular area, till 1985, the year in which an important reform was passed regarding the reception of refugees. The focal point of this immigration policy is singled out halfway in the 70's when the assimilation model is repudiated in favor of multiculturalism. One of the main features of this policy is the priority role accorded to research. The author examines the main fields of interest pursued by researchers, in particular the more recent studies on the ethnic-cultural dimension of the immigration phenomenon." (SUMMARY IN ENG AND FRE) excerpt

Tracking and data relay satellite system - NASA's new spacecraft data acquisition system

NASA Technical Reports Server (NTRS)

Schneider, W. C.; Garman, A. A.

1979-01-01

This paper describes NASA's new spacecraft acquisition system provided by the Tracking and Data Relay Satellite System (TDRSS). Four satellites in geostationary orbit and a ground terminal will provide complete tracking, telemetry, and command service for all of NASA's orbital satellites below a 12,000 km altitude. Western Union will lease the system, operate the ground terminal and provide operational satellite control. NASA's network control center will be the focal point for scheduling user services and controlling the interface between TDRSS and the NASA communications network, project control centers, and data processing. TDRSS single access user spacecraft data systems will be designed for time shared data relay support, and reimbursement policy and rate structure for non-NASA users are being developed.

The Role of Interface Shape on the Impact Characteristics and Cranial Fracture Patterns Using the Immature Porcine Head Model,.

PubMed

Vaughan, Patrick E; Vogelsberg, Caitlin C M; Vollner, Jennifer M; Fenton, Todd W; Haut, Roger C

2016-09-01

The forensic literature suggests that when adolescents fall onto edged and pointed surfaces, depressed fractures can occur at low energy levels. This study documents impact biomechanics and fracture characteristics of infant porcine skulls dropped onto flat, curved, edged, and focal surfaces. Results showed that the energy needed for fracture initiation was nearly four times higher against a flat surface than against the other surfaces. While characteristic measures of fracture such as number and length of fractures did not vary with impact surface shape, the fracture patterns did depend on impact surface shape. While experimental impacts against the flat surface produced linear fractures initiating at sutural boundaries peripheral to the point of impact (POI), more focal impacts produced depressed fractures initiating at the POI. The study supported case-based forensic literature suggesting cranial fracture patterns depend on impact surface shape and that fracture initiation energy is lower for more focal impacts. © 2016 American Academy of Forensic Sciences.

[Laparoscopy findings of the yellow spot, a focal fatty liver infiltration].

PubMed

Koch, H; Henning, H; Friedrich, K; Lüders, C J

1984-05-01

From 1976 to 1982 in 279 patients amongst 3719 laparoscopies focal fatty liver infiltrates were found at the right and/or left liver edge next to the insertion point of the round ligament. These so-called "yellow spots" mainly could be recognized in case of normal liver tissue and in cases suffering from chronic hepatitis insofar as a cirrhotic transformation or a significant fibrosis had not taken place. The localization and the shape of these focal lesions indicate, that an abnormality in the portal blood supply of the corresponding area may play an etiologic role for the development of the fatty infiltration.

The design and assembly of aluminum mirrors of a three-mirror-anastigmat telescope

NASA Astrophysics Data System (ADS)

Chang, Shenq-Tsong; Lin, Yu-Chuan; Wu, Kun-Huan; Lien, Chun-Chieh; Huang, Ting-Ming; Tsay, Ho-Lin; Chan, Chia-Yen

2017-09-01

Better ground sampling distance (GSD) has been a trend for earth observation satellites. A long-focal-length telescope is required accordingly in systematic point of view. On the other hand, there is size constraint for such long-focal-length telescope especially in space projects. Three-mirror-anastigmat (TMA) was proven to have excellent features of correcting aberrations, wide spectral range and shorter physical requirement [1-3].

NeuroSeek dual-color image processing infrared focal plane array

NASA Astrophysics Data System (ADS)

McCarley, Paul L.; Massie, Mark A.; Baxter, Christopher R.; Huynh, Buu L.

1998-09-01

Several technologies have been developed in recent years to advance the state of the art of IR sensor systems including dual color affordable focal planes, on-focal plane array biologically inspired image and signal processing techniques and spectral sensing techniques. Pacific Advanced Technology (PAT) and the Air Force Research Lab Munitions Directorate have developed a system which incorporates the best of these capabilities into a single device. The 'NeuroSeek' device integrates these technologies into an IR focal plane array (FPA) which combines multicolor Midwave IR/Longwave IR radiometric response with on-focal plane 'smart' neuromorphic analog image processing. The readout and processing integrated circuit very large scale integration chip which was developed under this effort will be hybridized to a dual color detector array to produce the NeuroSeek FPA, which will have the capability to fuse multiple pixel-based sensor inputs directly on the focal plane. Great advantages are afforded by application of massively parallel processing algorithms to image data in the analog domain; the high speed and low power consumption of this device mimic operations performed in the human retina.

Three-dimensional continuous particle focusing in a microfluidic channel via standing surface acoustic waves (SSAW).

PubMed

Shi, Jinjie; Yazdi, Shahrzad; Lin, Sz-Chin Steven; Ding, Xiaoyun; Chiang, I-Kao; Sharp, Kendra; Huang, Tony Jun

2011-07-21

Three-dimensional (3D) continuous microparticle focusing has been achieved in a single-layer polydimethylsiloxane (PDMS) microfluidic channel using a standing surface acoustic wave (SSAW). The SSAW was generated by the interference of two identical surface acoustic waves (SAWs) created by two parallel interdigital transducers (IDTs) on a piezoelectric substrate with a microchannel precisely bonded between them. To understand the working principle of the SSAW-based 3D focusing and investigate the position of the focal point, we computed longitudinal waves, generated by the SAWs and radiated into the fluid media from opposite sides of the microchannel, and the resultant pressure and velocity fields due to the interference and reflection of the longitudinal waves. Simulation results predict the existence of a focusing point which is in good agreement with our experimental observations. Compared with other 3D focusing techniques, this method is non-invasive, robust, energy-efficient, easy to implement, and applicable to nearly all types of microparticles.

Plenoptic background oriented schlieren imaging

NASA Astrophysics Data System (ADS)

Klemkowsky, Jenna N.; Fahringer, Timothy W.; Clifford, Christopher J.; Bathel, Brett F.; Thurow, Brian S.

2017-09-01

The combination of the background oriented schlieren (BOS) technique with the unique imaging capabilities of a plenoptic camera, termed plenoptic BOS, is introduced as a new addition to the family of schlieren techniques. Compared to conventional single camera BOS, plenoptic BOS is capable of sampling multiple lines-of-sight simultaneously. Displacements from each line-of-sight are collectively used to build a four-dimensional displacement field, which is a vector function structured similarly to the original light field captured in a raw plenoptic image. The displacement field is used to render focused BOS images, which qualitatively are narrow depth of field slices of the density gradient field. Unlike focused schlieren methods that require manually changing the focal plane during data collection, plenoptic BOS synthetically changes the focal plane position during post-processing, such that all focal planes are captured in a single snapshot. Through two different experiments, this work demonstrates that plenoptic BOS is capable of isolating narrow depth of field features, qualitatively inferring depth, and quantitatively estimating the location of disturbances in 3D space. Such results motivate future work to transition this single-camera technique towards quantitative reconstructions of 3D density fields.

Focal Activation of Cells by Plasmon Resonance Assisted Optical Injection of Signaling Molecules

PubMed Central

2015-01-01

Experimental methods for single cell intracellular delivery are essential for probing cell signaling dynamics within complex cellular networks, such as those making up the tumor microenvironment. Here, we show a quantitative and general method of interrogation of signaling pathways. We applied highly focused near-infrared laser light to optically inject gold-coated liposomes encapsulating bioactive molecules into single cells for focal activation of cell signaling. For this demonstration, we encapsulated either inositol trisphosphate (IP3), an endogenous cell signaling second messenger, or adenophostin A (AdA), a potent analogue of IP, within 100 nm gold-coated liposomes, and injected these gold-coated liposomes and their contents into the cytosol of single ovarian carcinoma cells to initiate calcium (Ca2+) release from intracellular stores. Upon optical injection of IP3 or AdA at doses above the activation threshold, we observed increases in cytosolic Ca2+ concentration within the injected cell initiating the propagation of a Ca2+ wave throughout nearby cells. As confirmed by octanol-induced inhibition, the intercellular Ca2+ wave traveled via gap junctions. Optical injection of gold-coated liposomes represents a quantitative method of focal activation of signaling cascades of broad interest in biomedical research. PMID:24877558

Operational Tree Species Mapping in a Diverse Tropical Forest with Airborne Imaging Spectroscopy.

PubMed

Baldeck, Claire A; Asner, Gregory P; Martin, Robin E; Anderson, Christopher B; Knapp, David E; Kellner, James R; Wright, S Joseph

2015-01-01

Remote identification and mapping of canopy tree species can contribute valuable information towards our understanding of ecosystem biodiversity and function over large spatial scales. However, the extreme challenges posed by highly diverse, closed-canopy tropical forests have prevented automated remote species mapping of non-flowering tree crowns in these ecosystems. We set out to identify individuals of three focal canopy tree species amongst a diverse background of tree and liana species on Barro Colorado Island, Panama, using airborne imaging spectroscopy data. First, we compared two leading single-class classification methods--binary support vector machine (SVM) and biased SVM--for their performance in identifying pixels of a single focal species. From this comparison we determined that biased SVM was more precise and created a multi-species classification model by combining the three biased SVM models. This model was applied to the imagery to identify pixels belonging to the three focal species and the prediction results were then processed to create a map of focal species crown objects. Crown-level cross-validation of the training data indicated that the multi-species classification model had pixel-level producer's accuracies of 94-97% for the three focal species, and field validation of the predicted crown objects indicated that these had user's accuracies of 94-100%. Our results demonstrate the ability of high spatial and spectral resolution remote sensing to accurately detect non-flowering crowns of focal species within a diverse tropical forest. We attribute the success of our model to recent classification and mapping techniques adapted to species detection in diverse closed-canopy forests, which can pave the way for remote species mapping in a wider variety of ecosystems.

Operational Tree Species Mapping in a Diverse Tropical Forest with Airborne Imaging Spectroscopy

PubMed Central

Baldeck, Claire A.; Asner, Gregory P.; Martin, Robin E.; Anderson, Christopher B.; Knapp, David E.; Kellner, James R.; Wright, S. Joseph

2015-01-01

Remote identification and mapping of canopy tree species can contribute valuable information towards our understanding of ecosystem biodiversity and function over large spatial scales. However, the extreme challenges posed by highly diverse, closed-canopy tropical forests have prevented automated remote species mapping of non-flowering tree crowns in these ecosystems. We set out to identify individuals of three focal canopy tree species amongst a diverse background of tree and liana species on Barro Colorado Island, Panama, using airborne imaging spectroscopy data. First, we compared two leading single-class classification methods—binary support vector machine (SVM) and biased SVM—for their performance in identifying pixels of a single focal species. From this comparison we determined that biased SVM was more precise and created a multi-species classification model by combining the three biased SVM models. This model was applied to the imagery to identify pixels belonging to the three focal species and the prediction results were then processed to create a map of focal species crown objects. Crown-level cross-validation of the training data indicated that the multi-species classification model had pixel-level producer’s accuracies of 94–97% for the three focal species, and field validation of the predicted crown objects indicated that these had user’s accuracies of 94–100%. Our results demonstrate the ability of high spatial and spectral resolution remote sensing to accurately detect non-flowering crowns of focal species within a diverse tropical forest. We attribute the success of our model to recent classification and mapping techniques adapted to species detection in diverse closed-canopy forests, which can pave the way for remote species mapping in a wider variety of ecosystems. PMID:26153693

Tegumental alterations of adult Schistosoma japonicum harbored in mice treated with a single oral dose of mefloquine.

PubMed

Xiao, Shu-hua; Xue, Jian; Shen, Bing-gui

2010-02-01

To observe the effect of mefloquine on the tegument of adult Schistosoma japonicum harbored in mice. Twelve mice were each infected with 60-80 S. japonicum cercariae. At 35 days post-infection, 10 mice were treated orally with mefloquine at a single dose of 400 mg/kg. Two mice were sacrificed at 8 h, 24 h, 3 days, 7 days, and 14 days post-treatment respectively, and schistosomes were collected by the perfusion technique, fixed and examined under a scanning electron microscope. Schistosomes obtained from the remaining 2 untreated mice served as control. 8 h post-treatment, male and female schistosomes showed focal swelling of the worm body accompanied by extensive swelling, tough junction and fusion of tegumental ridges. Meanwhile, some of the sensory structures showed enlargement and part of them collapsed. 24 h after mefloquine administration, head portion of some male and female worms revealed high swelling accompanied by severe damage to oral sucker. 3 days post-treatment, focal swelling of worm body along the whole worm was universal. In some male and female worms, the damaged tegument fused together to form a large mass protruding from the tegumental surface. In addition, focal or extensive peeling of tegumental ridges was seen or collapse of enlarged sensory structure resulted in formation of hole-like appearance. 7 days post administration, focal swelling of worm body and damage to tegument induced by mefloquine were similar to those aforementioned, but focal peeling, collapse of enlarged sensory structures, and deformation of oral sucker in male and female worms were universal. 14 days post-treatment, individual male worm survived the treatment revealed normal appearance of tegumental ridges in head portion, although light focal swelling of worm body was still observed. Mefloquine causes focal swelling of worm body, extensive and severe damage to the tegument in adult S. japonicum.

Tuskegee as Sacred Rhetoric: Focal Point for the Emergent Field of African American Religion and Health.

PubMed

Laws, Terri

2018-02-01

Scholars in African American religion engage the Tuskegee Syphilis Study as the focal point of the African American experience in institutional medicine. Seeking a way forward from this history and its intentional evil, the author proposes to position Tuskegee as a form of Lynch's culturally contextual sacred rhetoric to make use of its metaphoric value in the emerging field of African American religion and health. In this broader meaning-making frame, Tuskegee serves as a reminder that African American religious sensibility has long been an agential resource that counters abuse of the Black body. It also acknowledges the complex decisions facing African American clinical trial participants.

LGI1 microdeletion in autosomal dominant lateral temporal epilepsy

PubMed Central

Fanciulli, M.; Santulli, L.; Errichiello, L.; Barozzi, C.; Tomasi, L.; Rigon, L.; Cubeddu, T.; de Falco, A.; Rampazzo, A.; Michelucci, R.; Uzzau, S.; Striano, S.; de Falco, F.A.; Striano, P.

2012-01-01

Objectives: To characterize clinically and genetically a family with autosomal dominant lateral temporal epilepsy (ADLTE) negative to LGI1 exon sequencing test. Methods: All participants were personally interviewed and underwent neurologic examination. Most affected subjects underwent EEG and neuroradiologic examinations (CT/MRI). Available family members were genotyped with the HumanOmni1-Quad v1.0 single nucleotide polymorphism (SNP) array beadchip and copy number variations (CNVs) were analyzed in each subject. LGI1 gene dosage was performed by real-time quantitative PCR (qPCR). Results: The family had 8 affected members (2 deceased) over 3 generations. All of them showed GTC seizures, with focal onset in 6 and unknown onset in 2. Four patients had focal seizures with auditory features. EEG showed only minor sharp abnormalities in 3 patients and MRI was unremarkable in all the patients examined. Three family members presented major depression and anxiety symptoms. Routine LGI1 exon sequencing revealed no point mutation. High-density SNP array CNV analysis identified a genomic microdeletion about 81 kb in size encompassing the first 4 exons of LGI1 in all available affected members and in 2 nonaffected carriers, which was confirmed by qPCR analysis. Conclusions: This is the first microdeletion affecting LGI1 identified in ADLTE. Families with ADLTE in which no point mutations are revealed by direct exon sequencing should be screened for possible genomic deletion mutations by CNV analysis or other appropriate methods. Overall, CNV analysis of multiplex families may be useful for identifying microdeletions in novel disease genes. PMID:22496201

Image-guided Navigation of Single-element Focused Ultrasound Transducer

PubMed Central

Kim, Hyungmin; Chiu, Alan; Park, Shinsuk; Yoo, Seung-Schik

2014-01-01

The spatial specificity and controllability of focused ultrasound (FUS), in addition to its ability to modify the excitability of neural tissue, allows for the selective and reversible neuromodulation of the brain function, with great potential in neurotherapeutics. Intra-operative magnetic resonance imaging (MRI) guidance (in short, MRg) has limitations due to its complicated examination logistics, such as fixation through skull screws to mount the stereotactic frame, simultaneous sonication in the MRI environment, and restrictions in choosing MR-compatible materials. In order to overcome these limitations, an image-guidance system based on optical tracking and pre-operative imaging data is developed, separating the imaging acquisition for guidance and sonication procedure for treatment. Techniques to define the local coordinates of the focal point of sonication are presented. First, mechanical calibration detects the concentric rotational motion of a rigid-body optical tracker, attached to a straight rod mimicking the sonication path, pivoted at the virtual FUS focus. The spatial error presented in the mechanical calibration was compensated further by MRI-based calibration, which estimates the spatial offset between the navigated focal point and the ground-truth location of the sonication focus obtained from a temperature-sensitive MR sequence. MRI-based calibration offered a significant decrease in spatial errors (1.9±0.8 mm; 57% reduction) compared to the mechanical calibration method alone (4.4±0.9 mm). Using the presented method, pulse-mode FUS was applied to the motor area of the rat brain, and successfully stimulated the motor cortex. The presented techniques can be readily adapted for the transcranial application of FUS to intact human brain. PMID:25232203

Fast Confocal Raman Imaging Using a 2-D Multifocal Array for Parallel Hyperspectral Detection.

PubMed

Kong, Lingbo; Navas-Moreno, Maria; Chan, James W

2016-01-19

We present the development of a novel confocal hyperspectral Raman microscope capable of imaging at speeds up to 100 times faster than conventional point-scan Raman microscopy under high noise conditions. The microscope utilizes scanning galvomirrors to generate a two-dimensional (2-D) multifocal array at the sample plane, generating Raman signals simultaneously at each focus of the array pattern. The signals are combined into a single beam and delivered through a confocal pinhole before being focused through the slit of a spectrometer. To separate the signals from each row of the array, a synchronized scan mirror placed in front of the spectrometer slit positions the Raman signals onto different pixel rows of the detector. We devised an approach to deconvolve the superimposed signals and retrieve the individual spectra at each focal position within a given row. The galvomirrors were programmed to scan different focal arrays following Hadamard encoding patterns. A key feature of the Hadamard detection is the reconstruction of individual spectra with improved signal-to-noise ratio. Using polystyrene beads as test samples, we demonstrated not only that our system images faster than a conventional point-scan method but that it is especially advantageous under noisy conditions, such as when the CCD detector operates at fast read-out rates and high temperatures. This is the first demonstration of multifocal confocal Raman imaging in which parallel spectral detection is implemented along both axes of the CCD detector chip. We envision this novel 2-D multifocal spectral detection technique can be used to develop faster imaging spontaneous Raman microscopes with lower cost detectors.

A comparison of performance of lightweight mirrors

NASA Technical Reports Server (NTRS)

Cho, Myung K.; Richard, Ralph M.; Hileman, Edward A.

1990-01-01

Four lightweight solid contoured back mirror shapes (a double arch, a single arch, a modified single arch, and a double concave mirror) and a cellular sandwich lightweight meniscus mirror, have been considered for the primary mirror of the Space Infrared Telescope Facility (SIRTF). A parametric design study using these shapes for the SIRTF 40 inch primary mirror with a focal ratio f/2 is presented. Evaluations of the optical performance and fundamental frequency analyses are performed to compare relative merits of each mirror configuration. Included in these are structural, optical, and frequency analyses for (1) different back contour shapes, (2) different number and location of the support points, and (3) two gravity orientations (ZENITH and HORIZON positions). The finite element program NASTRAN is used to obtain the structural deflections of the optical surface. For wavefront error analysis, FRINGE and PCFRINGE programs are used to evaluate the optical performance. A scaling law relating the optical and structural performance for various mirror contoured back shapes is developed.

Tracking initially unresolved thrusting objects in 3D using a single stationary optical sensor

NASA Astrophysics Data System (ADS)

Lu, Qin; Bar-Shalom, Yaakov; Willett, Peter; Granström, Karl; Ben-Dov, R.; Milgrom, B.

2017-05-01

This paper considers the problem of estimating the 3D states of a salvo of thrusting/ballistic endo-atmospheric objects using 2D Cartesian measurements from the focal plane array (FPA) of a single fixed optical sensor. Since the initial separations in the FPA are smaller than the resolution of the sensor, this results in merged measurements in the FPA, compounding the usual false-alarm and missed-detection uncertainty. We present a two-step methodology. First, we assume a Wiener process acceleration (WPA) model for the motion of the images of the projectiles in the optical sensor's FPA. We model the merged measurements with increased variance, and thence employ a multi-Bernoulli (MB) filter using the 2D measurements in the FPA. Second, using the set of associated measurements for each confirmed MB track, we formulate a parameter estimation problem, whose maximum likelihood estimate can be obtained via numerical search and can be used for impact point prediction. Simulation results illustrate the performance of the proposed method.

Multiple wavelength X-ray monochromators

DOEpatents

Steinmeyer, P.A.

1992-11-17

An improved apparatus and method is provided for separating input x-ray radiation containing first and second x-ray wavelengths into spatially separate first and second output radiation which contain the first and second x-ray wavelengths, respectively. The apparatus includes a crystalline diffractor which includes a first set of parallel crystal planes, where each of the planes is spaced a predetermined first distance from one another. The crystalline diffractor also includes a second set of parallel crystal planes inclined at an angle with respect to the first set of crystal planes where each of the planes of the second set of parallel crystal planes is spaced a predetermined second distance from one another. In one embodiment, the crystalline diffractor is comprised of a single crystal. In a second embodiment, the crystalline diffractor is comprised of a stack of two crystals. In a third embodiment, the crystalline diffractor includes a single crystal that is bent for focusing the separate first and second output x-ray radiation wavelengths into separate focal points. 3 figs.

Automatic software correction of residual aberrations in reconstructed HRTEM exit waves of crystalline samples

DOE PAGES

Ophus, Colin; Rasool, Haider I.; Linck, Martin; ...

2016-11-30

We develop an automatic and objective method to measure and correct residual aberrations in atomic-resolution HRTEM complex exit waves for crystalline samples aligned along a low-index zone axis. Our method uses the approximate rotational point symmetry of a column of atoms or single atom to iteratively calculate a best-fit numerical phase plate for this symmetry condition, and does not require information about the sample thickness or precise structure. We apply our method to two experimental focal series reconstructions, imaging a β-Si 3N 4 wedge with O and N doping, and a single-layer graphene grain boundary. We use peak and latticemore » fitting to evaluate the precision of the corrected exit waves. We also apply our method to the exit wave of a Si wedge retrieved by off-axis electron holography. In all cases, the software correction of the residual aberration function improves the accuracy of the measured exit waves.« less

High dose rate brachytherapy source measurement intercomparison.

PubMed

Poder, Joel; Smith, Ryan L; Shelton, Nikki; Whitaker, May; Butler, Duncan; Haworth, Annette

2017-06-01

This work presents a comparison of air kerma rate (AKR) measurements performed by multiple radiotherapy centres for a single HDR 192 Ir source. Two separate groups (consisting of 15 centres) performed AKR measurements at one of two host centres in Australia. Each group travelled to one of the host centres and measured the AKR of a single 192 Ir source using their own equipment and local protocols. Results were compared to the 192 Ir source calibration certificate provided by the manufacturer by means of a ratio of measured to certified AKR. The comparisons showed remarkably consistent results with the maximum deviation in measurement from the decay-corrected source certificate value being 1.1%. The maximum percentage difference between any two measurements was less than 2%. The comparisons demonstrated the consistency of well-chambers used for 192 Ir AKR measurements in Australia, despite the lack of a local calibration service, and served as a valuable focal point for the exchange of ideas and dosimetry methods.

Automatic software correction of residual aberrations in reconstructed HRTEM exit waves of crystalline samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ophus, Colin; Rasool, Haider I.; Linck, Martin

We develop an automatic and objective method to measure and correct residual aberrations in atomic-resolution HRTEM complex exit waves for crystalline samples aligned along a low-index zone axis. Our method uses the approximate rotational point symmetry of a column of atoms or single atom to iteratively calculate a best-fit numerical phase plate for this symmetry condition, and does not require information about the sample thickness or precise structure. We apply our method to two experimental focal series reconstructions, imaging a β-Si 3N 4 wedge with O and N doping, and a single-layer graphene grain boundary. We use peak and latticemore » fitting to evaluate the precision of the corrected exit waves. We also apply our method to the exit wave of a Si wedge retrieved by off-axis electron holography. In all cases, the software correction of the residual aberration function improves the accuracy of the measured exit waves.« less

Multiple wavelength X-ray monochromators

DOEpatents

Steinmeyer, Peter A.

1992-11-17

An improved apparatus and method is provided for separating input x-ray radiation containing first and second x-ray wavelengths into spatially separate first and second output radiation which contain the first and second x-ray wavelengths, respectively. The apparatus includes a crystalline diffractor which includes a first set of parallel crystal planes, where each of the planes is spaced a predetermined first distance from one another. The crystalline diffractor also includes a second set of parallel crystal planes inclined at an angle with respect to the first set of crystal planes where each of the planes of the second set of parallel crystal planes is spaced a predetermined second distance from one another. In one embodiment, the crystalline diffractor is comprised of a single crystal. In a second embodiment, the crystalline diffractor is comprised of a stack of two crystals. In a third embodiment, the crystalline diffractor includes a single crystal that is bent for focussing the separate first and second output x-ray radiation wavelengths into separate focal points.

Phase-Scrambler Plate Spreads Point Image

NASA Technical Reports Server (NTRS)

Edwards, Oliver J.; Arild, Tor

1992-01-01

Array of small prisms retrofit to imaging lens. Phase-scrambler plate essentially planar array of small prisms partitioning aperture of lens into many subapertures, and prism at each subaperture designed to divert relatively large diffraction spot formed by that subaperture to different, specific point on focal plane.

Capability of long distance 100  GHz FMCW using a single GDD lamp sensor.

PubMed

Levanon, Assaf; Rozban, Daniel; Aharon Akram, Avihai; Kopeika, Natan S; Yitzhaky, Yitzhak; Abramovich, Amir

2014-12-20

Millimeter wave (MMW)-based imaging systems are required for applications in medicine, homeland security, concealed weapon detection, and space technology. The lack of inexpensive room temperature imaging sensors makes it difficult to provide a suitable MMW system for many of the above applications. A 3D MMW imaging system based on chirp radar was studied previously using a scanning imaging system of a single detector. The radar system requires that the millimeter wave detector will be able to operate as a heterodyne detector. Since the source of radiation is a frequency modulated continuous wave (FMCW), the detected signal as a result of heterodyne detection gives the object's depth information according to value of difference frequency, in addition to the reflectance of the 2D image. New experiments show the capability of long distance FMCW detection by using a large scale Cassegrain projection system, described first (to our knowledge) in this paper. The system presents the capability to employ a long distance of at least 20 m with a low-cost plasma-based glow discharge detector (GDD) focal plane array (FPA). Each point on the object corresponds to a point in the image and includes the distance information. This will enable relatively inexpensive 3D MMW imaging.

Optomechanical System Development of the AWARE Gigapixel Scale Camera

NASA Astrophysics Data System (ADS)

Son, Hui S.

Electronic focal plane arrays (FPA) such as CMOS and CCD sensors have dramatically improved to the point that digital cameras have essentially phased out film (except in very niche applications such as hobby photography and cinema). However, the traditional method of mating a single lens assembly to a single detector plane, as required for film cameras, is still the dominant design used in cameras today. The use of electronic sensors and their ability to capture digital signals that can be processed and manipulated post acquisition offers much more freedom of design at system levels and opens up many interesting possibilities for the next generation of computational imaging systems. The AWARE gigapixel scale camera is one such computational imaging system. By utilizing a multiscale optical design, in which a large aperture objective lens is mated with an array of smaller, well corrected relay lenses, we are able to build an optically simple system that is capable of capturing gigapixel scale images via post acquisition stitching of the individual pictures from the array. Properly shaping the array of digital cameras allows us to form an effectively continuous focal surface using off the shelf (OTS) flat sensor technology. This dissertation details developments and physical implementations of the AWARE system architecture. It illustrates the optomechanical design principles and system integration strategies we have developed through the course of the project by summarizing the results of the two design phases for AWARE: AWARE-2 and AWARE-10. These systems represent significant advancements in the pursuit of scalable, commercially viable snapshot gigapixel imaging systems and should serve as a foundation for future development of such systems.

High spatial resolution technique for SPECT using a fan-beam collimator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ichihar, T.; Nambu, K.; Motomura, N.

1993-08-01

The physical characteristics of the collimator cause degradation of resolution with increasing distance from the collimator surface. A new convolutional backprojection algorithm has been derived for fanbeam SPECT data without rebinding into parallel beam geometry. The projections are filtered and then backprojected into the area within an isosceles triangle whose vertex is the focal point of the fan-beam and whose base is the fan-beam collimator face, and outside of the circle whose center is located midway between the focal point and the center of rotation and whose diameter is the distance between the focal point and the center of rotation.more » Consequently the backprojected area is close to the collimator surface. This algorithm has been implemented on a GCA-9300A SPECT system showing good results with both phantom and patient studies. The SPECT transaxial resolution was 4.6mm FWHM (reconstructed image matrix size of 256x256) at the center of SPECT FOV using UHR (ultra-high-resolution) fan beam collimators for brain study. Clinically, Tc-99m HMPAO and Tc-99m ECD brain data were reconstructed using this algorithm. The reconstruction results were compared with MRI images of the same slice position and showed significantly improved over results obtained with standard reconstruction algorithms.« less

Research Technology

NASA Image and Video Library

1999-08-01

Researchers at the Marshall Space Flight Center (MSFC) have designed, fabricated, and tested the first solar thermal engine, a non-chemical rocket engine that produces lower thrust but has better thrust efficiency than a chemical combustion engine. MSFC turned to solar thermal propulsion in the early 1990s due to its simplicity, safety, low cost, and commonality with other propulsion systems. Solar thermal propulsion works by acquiring and redirecting solar energy to heat a propellant. The 20- by 24-ft heliostat mirror (not shown in this photograph) has dual-axis control that keeps a reflection of the sunlight on an 18-ft diameter concentrator mirror, which then focuses the sunlight to a 4-in focal point inside the vacuum chamber. The focal point has 10 kilowatts of intense solar power. This photograph is a close-up view of a 4-in focal point inside the vacuum chamber at the MSFC Solar Thermal Propulsion Test facility. As part of MSFC's Space Transportation Directorate, the Propulsion Research Center serves as a national resource for research of advanced, revolutionary propulsion technologies. The mission is to move the Nation's capabilities beyond the confines of conventional chemical propulsion into an era of aircraft-like access to Earth orbit, rapid travel throughout the solar system, and exploration of interstellar space.

Research Technology

NASA Image and Video Library

1999-08-01

Researchers at the Marshall Space Flight Center (MSFC) have designed, fabricated and tested the first solar thermal engine, a non-chemical rocket engine that produces lower thrust but has better thrust efficiency than a chemical combustion engine. MSFC turned to solar thermal propulsion in the early 1990s due to its simplicity, safety, low cost, and commonality with other propulsion systems. Solar thermal propulsion works by acquiring and redirecting solar energy to heat a propellant. This photograph, taken at MSFC's Solar Thermal Propulsion Test Facility, shows a concentrator mirror, a combination of 144 mirrors forming this 18-ft diameter concentrator, and a vacuum chamber that houses the focal point. The 20- by 24-ft heliostat mirror (not shown in this photograph) has a dual-axis control that keeps a reflection of the sunlight on the 18-foot diameter concentrator mirror, which then focuses the sunlight to a 4-in focal point inside the vacuum chamber. The focal point has 10 kilowatts of intense solar power. As part of MSFC's Space Transportation Directorate, the Propulsion Research Center serves as a national resource for research of advanced, revolutionary propulsion technologies. The mission is to move the Nation's capabilities beyond the confines of conventional chemical propulsion into an era of aircraft-like access to Earth-orbit, rapid travel throughout the solar system, and exploration of interstellar space.

Solar Thermal Propulsion Test Facility

NASA Technical Reports Server (NTRS)

1999-01-01

Researchers at the Marshall Space Flight Center (MSFC) have designed, fabricated and tested the first solar thermal engine, a non-chemical rocket engine that produces lower thrust but has better thrust efficiency than a chemical combustion engine. MSFC turned to solar thermal propulsion in the early 1990s due to its simplicity, safety, low cost, and commonality with other propulsion systems. Solar thermal propulsion works by acquiring and redirecting solar energy to heat a propellant. This photograph, taken at MSFC's Solar Thermal Propulsion Test Facility, shows a concentrator mirror, a combination of 144 mirrors forming this 18-ft diameter concentrator, and a vacuum chamber that houses the focal point. The 20- by 24-ft heliostat mirror (not shown in this photograph) has a dual-axis control that keeps a reflection of the sunlight on the 18-foot diameter concentrator mirror, which then focuses the sunlight to a 4-in focal point inside the vacuum chamber. The focal point has 10 kilowatts of intense solar power. As part of MSFC's Space Transportation Directorate, the Propulsion Research Center serves as a national resource for research of advanced, revolutionary propulsion technologies. The mission is to move the Nation's capabilities beyond the confines of conventional chemical propulsion into an era of aircraft-like access to Earth-orbit, rapid travel throughout the solar system, and exploration of interstellar space.

Should consciousness describe seizures and what terms should be applied? Epilepsia's survey results.

PubMed

Mathern, Gary W; Beninsig, Laurie; Nehlig, Astrid

2015-03-01

From May to September 2014, Epilepsia conducted an online survey seeking opinions on whether consciousness should be used in describing focal and generalized seizures, and what terms should be applied to describe focal seizures with loss of awareness and amnesia. This study reports the findings of that survey. Two questions asked if consciousness should be used to classify seizures and what terms should be applied. Another four questions addressed demographic information. Of 209 individuals that started the poll, 147 (70.3%) completing it, and most that completed it were epileptologists (66%) from Europe (41%) and North America (27%). A majority (64%) indicated that the presence or absence of consciousness should be used to describe focal and generalized seizures, whereas 23% said it should not be used. When asked what term should be used to describe focal seizures with altered awareness and amnesia, 36% said focal impaired consciousness seizures (FICS), 30% selected complex partial seizures (CPS), and 16% answered focal dyscognitive seizures. This survey indicates that most responders prefer that consciousness be considered in the description of focal and generalized seizures, despite the difficulty in determining awareness clinically. Furthermore, responders could not agree on a single term that could be used to define focal seizures with loss of awareness and amnesia. Wiley Periodicals, Inc. © 2014 International League Against Epilepsy.

Design of Highly Articulated Mechanism for Surgical Applications

DTIC Science & Technology

2016-08-31

Army including surgery in the field and surgical bomb disarming. The views, opinions and/or findings contained in this report are those of the...many applications important to the Army including surgery in the field and surgical bomb disarming. We use minimally invasive surgery as a focal point...have many applications important to the Army including surgery in the field and surgical bomb disarming. We use minimally invasive surgery as a focal

Interferometric angle monitor

NASA Technical Reports Server (NTRS)

Minott, P. O. (Inventor)

1983-01-01

Two mutually coherent light beams formed from a single monochromatic light source were directed to a reflecting surface of a rotatable object. They were reflected into an imaging optical lens having a focal plane optically at infinity. A series of interference fringes were formed in the focal plane which were translated linearly in response to angular rotation of the object. Photodetectors were located adjacent the focal plane to detect the fringe translation and output a signal in response to the translation. The signal was fed to a signal processor which was adapted to count the number of fringes detected and develop a measure of the angular rotation and direction of the object.

Gene genealogies for genetic association mapping, with application to Crohn's disease

PubMed Central

Burkett, Kelly M.; Greenwood, Celia M. T.; McNeney, Brad; Graham, Jinko

2013-01-01

A gene genealogy describes relationships among haplotypes sampled from a population. Knowledge of the gene genealogy for a set of haplotypes is useful for estimation of population genetic parameters and it also has potential application in finding disease-predisposing genetic variants. As the true gene genealogy is unknown, Markov chain Monte Carlo (MCMC) approaches have been used to sample genealogies conditional on data at multiple genetic markers. We previously implemented an MCMC algorithm to sample from an approximation to the distribution of the gene genealogy conditional on haplotype data. Our approach samples ancestral trees, recombination and mutation rates at a genomic focal point. In this work, we describe how our sampler can be used to find disease-predisposing genetic variants in samples of cases and controls. We use a tree-based association statistic that quantifies the degree to which case haplotypes are more closely related to each other around the focal point than control haplotypes, without relying on a disease model. As the ancestral tree is a latent variable, so is the tree-based association statistic. We show how the sampler can be used to estimate the posterior distribution of the latent test statistic and corresponding latent p-values, which together comprise a fuzzy p-value. We illustrate the approach on a publicly-available dataset from a study of Crohn's disease that consists of genotypes at multiple SNP markers in a small genomic region. We estimate the posterior distribution of the tree-based association statistic and the recombination rate at multiple focal points in the region. Reassuringly, the posterior mean recombination rates estimated at the different focal points are consistent with previously published estimates. The tree-based association approach finds multiple sub-regions where the case haplotypes are more genetically related than the control haplotypes, and that there may be one or multiple disease-predisposing loci. PMID:24348515

High-Performance LWIR Superlattice Detectors and FPA Based on CBIRD Design

NASA Technical Reports Server (NTRS)

Soibel, Alexander; Nguyen, Jean; Rafol, Sir B.; Liao, Anna; Hoeglund, Linda; Khoshakhlagh, Arezou; Keo, Sam A.; Mumolo, Jason M.; Liu, John; Ting, David Z.-Y.;

High-Performance LWIR Superlattice Detectors and FPA Based on CBIRD Design

NASA Technical Reports Server (NTRS)

Soibel, Alexander; Nguyen, Jean; Rafol, Sir B.; Liao, Anna; Hoeglund, Linda; Khoshakhlagh, Arezou; Keo, Sam A.; Mumolo, Jason M.; Liu, John; Ting, David Z.-Y.;

Image Processing for Cameras with Fiber Bundle Image Relay

DTIC Science & Technology

length. Optical fiber bundles have been used to couple between this focal surface and planar image sensors . However, such fiber-coupled imaging systems...coupled to six discrete CMOS focal planes. We characterize the locally space-variant system impulse response at various stages: monocentric lens image...vignetting, and stitch together the image data from discrete sensors into a single panorama. We compare processed images from the prototype to those taken with

Methodological Aspects of Subjective Life Expectancy: Effects of Culture-Specific Reporting Heterogeneity Among Older Adults in the United States.

PubMed

Lee, Sunghee; Smith, Jacqui

2016-05-01

Subjective life expectancy (SLE) has been suggested as a predictor of mortality and mortality-related behaviors. Although critical for culturally diverse societies, these findings do not consider cross-cultural methodological comparability. Culture-specific reporting heterogeneity is a well-known phenomenon introducing biases, and research on this issue with SLE is not established. Using data from the Health and Retirement Study, we examined reporting heterogeneity in SLE focusing on item nonresponse, focal points, and reports over time for five ethnic-cultural groups: non-Hispanic Whites, non-Hispanic Blacks, non-Hispanic other races, English-interviewed Hispanics, and Spanish-interviewed Hispanics. On item nonresponse, Spanish-interviewed Hispanics said, "I don't know," to SLE significantly more than any other groups. Nearly half of the respondents chose 0, 50, or 100, making them focal points. However, the focal points differed: 50 for Whites, 100 for Blacks, and 0 for Spanish-interviewed Hispanics. The relationship of SLE measured at two time points was higher for Whites than minorities. Moreover, those who said "I don't know" to SLE showed higher subsequent mortality than those who gave an answer. SLE was not a significant mortality predictor for Hispanics. Overall, SLE is not free from culture-specific reporting heterogeneity. This warrants further research about its culture-relevant measurement mechanisms. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

An Adaptation-Induced Repulsion Illusion in Tactile Spatial Perception

PubMed Central

Li, Lux; Chan, Arielle; Iqbal, Shah M.; Goldreich, Daniel

2017-01-01

Following focal sensory adaptation, the perceived separation between visual stimuli that straddle the adapted region is often exaggerated. For instance, in the tilt aftereffect illusion, adaptation to tilted lines causes subsequently viewed lines with nearby orientations to be perceptually repelled from the adapted orientation. Repulsion illusions in the nonvisual senses have been less studied. Here, we investigated whether adaptation induces a repulsion illusion in tactile spatial perception. In a two-interval forced-choice task, participants compared the perceived separation between two point-stimuli applied on the forearms successively. Separation distance was constant on one arm (the reference) and varied on the other arm (the comparison). In Experiment 1, we took three consecutive baseline measurements, verifying that in the absence of manipulation, participants’ distance perception was unbiased across arms and stable across experimental blocks. In Experiment 2, we vibrated a region of skin on the reference arm, verifying that this focally reduced tactile sensitivity, as indicated by elevated monofilament detection thresholds. In Experiment 3, we applied vibration between the two reference points in our distance perception protocol and discovered that this caused an illusory increase in the separation between the points. We conclude that focal adaptation induces a repulsion aftereffect illusion in tactile spatial perception. The illusion provides clues as to how the tactile system represents spatial information. The analogous repulsion aftereffects caused by adaptation in different stimulus domains and sensory systems may point to fundamentally similar strategies for dynamic sensory coding. PMID:28701936

Basin boundaries and focal points in a map coming from Bairstow's method.

PubMed

Gardini, Laura; Bischi, Gian-Italo; Fournier-Prunaret, Daniele

1999-06-01

This paper is devoted to the study of the global dynamical properties of a two-dimensional noninvertible map, with a denominator which can vanish, obtained by applying Bairstow's method to a cubic polynomial. It is shown that the complicated structure of the basins of attraction of the fixed points is due to the existence of singularities such as sets of nondefinition, focal points, and prefocal curves, which are specific to maps with a vanishing denominator, and have been recently introduced in the literature. Some global bifurcations that change the qualitative structure of the basin boundaries, are explained in terms of contacts among these singularities. The techniques used in this paper put in evidence some new dynamic behaviors and bifurcations, which are peculiar of maps with denominator; hence they can be applied to the analysis of other classes of maps coming from iterative algorithms (based on Newton's method, or others). (c) 1999 American Institute of Physics.

Image motion compensation on the Spacelab 2 Solar Optical Universal Polarimeter /SL2 SOUP/

NASA Technical Reports Server (NTRS)

Tarbell, T. D.; Duncan, D. W.; Finch, M. L.; Spence, G.

1981-01-01

The SOUP experiment on Spacelab 2 includes a 30 cm visible light telescope and focal plane package mounted on the Instrument Pointing System (IPS). Scientific goals of the experiment dictate pointing stability requirements of less than 0.05 arcsecond jitter over periods of 5-20 seconds. Quantitative derivations of these requirements from two different aspects are presented: (1) avoidance of motion blurring of diffraction-limited images; (2) precise coalignment of consecutive frames to allow measurement of small image differences. To achieve this stability, a fine guider system capable of removing residual jitter of the IPS and image motions generated on the IPS cruciform instrument support structure has been constructed. This system uses solar limb detectors in the prime focal plane to derive an error signal. Image motion due to pointing errors is compensated by the agile secondary mirror mounted on piezoelectric transducers, controlled by a closed-loop servo system.

Single-stage cartilage repair in the knee with microfracture covered with a resorbable polymer-based matrix and autologous bone marrow concentrate.

PubMed

Enea, D; Cecconi, S; Calcagno, S; Busilacchi, A; Manzotti, S; Kaps, C; Gigante, A

2013-12-01

Different single-stage surgical approaches are currently under evaluation to repair focal cartilage lesions. This study aims to analyze the clinical and histological results after treatment of focal condylar articular lesions of the knee with microfracture and subsequent covering with a resorbable polyglycolic acid/hyaluronan (PGA -HA) matrix augmented with autologous bone marrow concentrate (BMC). Nine patients with focal lesions of the condylar articular cartilage were consecutively treated with arthroscopic PGA -HA-covered microfracture and bone marrow concentrate (PGA -HA-CMBMC). Patients were retrospectively assessed using standardized assessment tools and magnetic resonance imaging (MRI). Five patients consented to undergo second look arthroscopy and 2 consented biopsy harvest. All the patients but one showed improvement in clinical scoring from the pre-operative situation to the latest follow-up (average 22±2months). The mean IKDC subjective score, Lysholm score, VAS and the median Tegner score significantly increased from baseline to the latest follow-up. Cartilage macroscopic assessment at 12months revealed that one repair appeared normal, three almost normal and one appeared abnormal. Histological analysis proofed hyaline-like cartilage repair tissue formation in one case. MRI at 8 to 12months follow-up showed complete defect filling. The first clinical experience with single-stage treatment of focal cartilage defects of the knee with microfracture and covering with the PGA -HA matrix augmented with autologous BMC (PGA -HA-CMBMC) suggests that it is safe, it improves knee function and has the potential to regenerate hyaline-like cartilage. IV, case series. Copyright © 2013 Elsevier B.V. All rights reserved.

Bring the Pythagorean Theorem "Full Circle"

ERIC Educational Resources Information Center

Benson, Christine C.; Malm, Cheryl G.

2011-01-01

Middle school mathematics generally explores applications of the Pythagorean theorem and lays the foundation for working with linear equations. The Grade 8 Curriculum Focal Points recommend that students "apply the Pythagorean theorem to find distances between points in the Cartesian coordinate plane to measure lengths and analyze polygons and…

An HBCU Transformed

ERIC Educational Resources Information Center

Roach, Ronald

2006-01-01

Few institutions have embodied African-American history as completely as Wilberforce University. Established before the Civil War, the nation's oldest private Black college was a powerful focal point in the struggle for equality and served as a destination point on the Ohio Underground Railroad. Closed briefly during the Civil War, officials with…

Focal Adhesion-Independent Cell Migration.

PubMed

Paluch, Ewa K; Aspalter, Irene M; Sixt, Michael

2016-10-06

Cell migration is central to a multitude of physiological processes, including embryonic development, immune surveillance, and wound healing, and deregulated migration is key to cancer dissemination. Decades of investigations have uncovered many of the molecular and physical mechanisms underlying cell migration. Together with protrusion extension and cell body retraction, adhesion to the substrate via specific focal adhesion points has long been considered an essential step in cell migration. Although this is true for cells moving on two-dimensional substrates, recent studies have demonstrated that focal adhesions are not required for cells moving in three dimensions, in which confinement is sufficient to maintain a cell in contact with its substrate. Here, we review the investigations that have led to challenging the requirement of specific adhesions for migration, discuss the physical mechanisms proposed for cell body translocation during focal adhesion-independent migration, and highlight the remaining open questions for the future.

Theory of a Quantum Scanning Microscope for Cold Atoms

NASA Astrophysics Data System (ADS)

Yang, D.; Laflamme, C.; Vasilyev, D. V.; Baranov, M. A.; Zoller, P.

2018-03-01

We propose and analyze a scanning microscope to monitor "live" the quantum dynamics of cold atoms in a cavity QED setup. The microscope measures the atomic density with subwavelength resolution via dispersive couplings to a cavity and homodyne detection within the framework of continuous measurement theory. We analyze two modes of operation. First, for a fixed focal point the microscope records the wave packet dynamics of atoms with time resolution set by the cavity lifetime. Second, a spatial scan of the microscope acts to map out the spatial density of stationary quantum states. Remarkably, in the latter case, for a good cavity limit, the microscope becomes an effective quantum nondemolition device, such that the spatial distribution of motional eigenstates can be measured backaction free in single scans, as an emergent quantum nondemolition measurement.

Theory of a Quantum Scanning Microscope for Cold Atoms.

PubMed

Yang, D; Laflamme, C; Vasilyev, D V; Baranov, M A; Zoller, P

2018-03-30

We propose and analyze a scanning microscope to monitor "live" the quantum dynamics of cold atoms in a cavity QED setup. The microscope measures the atomic density with subwavelength resolution via dispersive couplings to a cavity and homodyne detection within the framework of continuous measurement theory. We analyze two modes of operation. First, for a fixed focal point the microscope records the wave packet dynamics of atoms with time resolution set by the cavity lifetime. Second, a spatial scan of the microscope acts to map out the spatial density of stationary quantum states. Remarkably, in the latter case, for a good cavity limit, the microscope becomes an effective quantum nondemolition device, such that the spatial distribution of motional eigenstates can be measured backaction free in single scans, as an emergent quantum nondemolition measurement.

Real time quantitative phase microscopy based on single-shot transport of intensity equation (ssTIE) method

NASA Astrophysics Data System (ADS)

Yu, Wei; Tian, Xiaolin; He, Xiaoliang; Song, Xiaojun; Xue, Liang; Liu, Cheng; Wang, Shouyu

2016-08-01

Microscopy based on transport of intensity equation provides quantitative phase distributions which opens another perspective for cellular observations. However, it requires multi-focal image capturing while mechanical and electrical scanning limits its real time capacity in sample detections. Here, in order to break through this restriction, real time quantitative phase microscopy based on single-shot transport of the intensity equation method is proposed. A programmed phase mask is designed to realize simultaneous multi-focal image recording without any scanning; thus, phase distributions can be quantitatively retrieved in real time. It is believed the proposed method can be potentially applied in various biological and medical applications, especially for live cell imaging.

Average focal length and power of a section of any defined surface.

PubMed

Kaye, Stephen B

2010-04-01

To provide a method to allow calculation of the average focal length and power of a lens through a specified meridian of any defined surface, not limited to the paraxial approximations. University of Liverpool, Liverpool, United Kingdom. Functions were derived to model back-vertex focal length and representative power through a meridian containing any defined surface. Average back-vertex focal length was based on the definition of the average of a function, using the angle of incidence as an independent variable. Univariate functions allowed determination of average focal length and power through a section of any defined or topographically measured surface of a known refractive index. These functions incorporated aberrations confined to the section. The proposed method closely approximates the average focal length, and by inference power, of a section (meridian) of a surface to a single or scalar value. It is not dependent on the paraxial and other nonconstant approximations and includes aberrations confined to that meridian. A generalization of this method to include all orthogonal and oblique meridians is needed before a comparison with measured wavefront values can be made. Copyright (c) 2010 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Breakdown simulations in a focused microwave beam within the simplified model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Semenov, V. E.; Rakova, E. I.; Glyavin, M. Yu.

2016-07-15

The simplified model is proposed to simulate numerically air breakdown in a focused microwave beam. The model is 1D from the mathematical point of view, but it takes into account the spatial non-uniformity of microwave field amplitude along the beam axis. The simulations are completed for different frequencies and different focal lengths of microwave beams. The results demonstrate complicated regimes of the breakdown evolution which represents a series of repeated ionization waves. These waves start at the focal point and propagate towards incident microwave radiation. The ionization wave parameters vary during propagation. At relatively low frequencies, the propagation regime ofmore » subsequent waves can also change qualitatively. Each next ionization wave is less pronounced than the previous one, and the breakdown evolution approaches the steady state with relatively small plasma density. The ionization wave parameters are sensitive to the weak source of external ionization, but the steady state is independent on such a source. As the beam focal length decreases, the stationary plasma density increases and the onset of the steady state occurs faster.« less

Solution for the nonuniformity correction of infrared focal plane arrays.

PubMed

Zhou, Huixin; Liu, Shangqian; Lai, Rui; Wang, Dabao; Cheng, Yubao

2005-05-20

Based on the S-curve model of the detector response of infrared focal plan arrays (IRFPAs), an improved two-point correction algorithm is presented. The algorithm first transforms the nonlinear image data into linear data and then uses the normal two-point algorithm to correct the linear data. The algorithm can effectively overcome the influence of nonlinearity of the detector's response, and it enlarges the correction precision and the dynamic range of the response. A real-time imaging-signal-processing system for IRFPAs that is based on a digital signal processor and field-programmable gate arrays is also presented. The nonuniformity correction capability of the presented solution is validated by experimental imaging procedures of a 128 x 128 pixel IRFPA camera prototype.

On a focal point instability in (B3Πg - C3Πu)N2 optogalvanic circuit with hollow cathode

NASA Astrophysics Data System (ADS)

Gencheva, V.

2016-03-01

The (B3Πg, v = 0 - C3 Πu, v = 0) N2 dynamic optogalvanic signals have been registered illuminating an Al hollow cathode lamp with a pulsed N2 laser generating at the wavelength of 337.1nm. The dynamic optogalvanic signal (DOGS) at certain discharge current of 8 mA is a harmonic oscillator due to a focal point instability produced by our optogalvanic circuit. This damped harmonic oscillator can be described as a solution of linear second order homogeneous differential equation. The oscillation frequency is estimated from the registered DOGS using Fourier synthesis. The analytical description of the damped harmonic DOGS is obtained.

Low cost point focus solar concentrator, phase 1

NASA Technical Reports Server (NTRS)

1979-01-01

Design concepts and plans for mass-production facilities and equipment, field installation, and maintenance were developed and used for cost analysis of a pneumatically stabilized plastic film point focus solar concentrator which has potential application in conjunction with Brayton cycle engines or supply of thermal energy. A sub-scale reflector was fabricated and optically tested by laser ray tracing to determine focal deviations of the surface slope and best focal plane. These test data were then used for comparisons with theoretical concentrator performance modeling and predictions of full-scale design performance. Results of the economic study indicate the concentrator design will have low cost when mass-produced and has cost/performance parameters that fall within current Jet Propulsion Laboratory goals.

An alignment method for mammographic X-ray spectroscopy under clinical conditions.

PubMed

Miyajima, S; Imagawa, K; Matsumoto, M

2002-09-01

This paper describes an alignment method for mammographic X-ray spectroscopy under clinical conditions. A pinhole, a fluorescent screen, a laser device and the case for a detector are used for alignment of the focal spot, a collimator and a detector. The method determines the line between the focal spot and the point of interest in an X-ray field radiographically. The method allows alignment for both central axis and off-axis directions.

Focal necrotizing pneumonia is a distinct entity from lung abscess.

PubMed

Seo, Hyewon; Cha, Seung-Ick; Shin, Kyung-Min; Lim, Jaekwang; Yoo, Seung-Soo; Lee, Jaehee; Lee, Shin-Yup; Kim, Chang-Ho; Park, Jae-Yong

2013-10-01

'Focal necrotizing pneumonia' was defined as a localized type of necrotizing pneumonia characterized by a single or few cavities of low density without rim enhancement on computed tomography (CT) scan. The purpose of this study was to investigate the clinical features and course of patients with focal necrotizing pneumonia, thereby elucidating its clinical relevance. The present study was conducted retrospectively in patients who had been interpreted as having lung abscess or necrotizing pneumonia on CT scan. Clinical and radiological characteristics were compared between the focal necrotizing pneumonia and lung abscess groups. Overall, 68 patients with focal necrotizing pneumonia (n = 35) or lung abscess (n = 33) were included in the present study. The frequency of risk factors for aspiration was significantly lower in the focal necrotizing group, compared with the lung abscess group (14.3% vs 45.5%, P = 0.005). Compared with lung abscess, focal necrotizing pneumonia was observed more commonly in non-gravity-dependent segments (66% vs 36%, P < 0.001). In addition, a trend towards more common isolation of aerobes as potential pathogens was observed in the focal necrotizing pneumonia group, compared with the lung abscess group (31% vs 12%, P = 0.08). However, in terms of treatment outcomes, a similar high rate of success was observed in both groups: 97%, respectively. Compared to lung abscess, focal necrotizing pneumonia occurs more commonly in non-gravity-dependent segments with lower incidence of risk factors for aspiration. Similar to lung abscess, the rate of success for treatment of focal necrotizing pneumonia was high. © 2013 The Authors. Respirology © 2013 Asian Pacific Society of Respirology.

Non-invasive identification of stable rotors and focal sources for human atrial fibrillation: mechanistic classification of atrial fibrillation from the electrocardiogram.

PubMed

Jones, Aled R; Krummen, David E; Narayan, Sanjiv M

2013-09-01

To develop electrocardiogram (ECG) tools to quantify the number of sources for atrial fibrillation (AF), i.e. spatially stable rotors and focal impulses, and whether they lie in right or left atrium. Intracardiac mapping has recently shown that paroxysmal and persistent AF is sustained by rotors or focal sources that are stable in location and thus targets for limited ablation [focal impulse and rotor modulation (FIRM)] to eliminate AF. Importantly, the numbers and locations of concurrent sources determine both the complexity of AF and the approach for ablation. In 36 AF patients (n = 29 persistent, 63 ± 9 years) in the CONventional ablation with or without Focal Impulse and Rotor Modulation (CONFIRM) trial, we developed phase lock (PL) to quantify spatial repeatability of ECG 'F-waves' between leads over time. Phase lock spectrally quantifies the angle θ between F-wave voltages in planes formed by ECG leads I, aVF, and V1 at successive points in time. We compared PL with ECG spectral dominant frequency (DF) and organizational index (OI) to characterize stable rotors and focal sources validated by intracardiac FIRM mapping. Focal impulse and rotor modulation ablation alone at ≤3 sources acutely terminated and rendered AF non-inducible or substantially slowed AF in 31 of 36 patients. Receiver operating characteristics of PL for this endpoint had area under the curve (AUC) = 0.72, and the optimum cut-point (PL = 0.09) had 74% sensitivity, 92% positive predictive value (PPV). Receiver operating characteristics areas for OI and DF were 0.50 and 0.58, respectively. Left (n = 28) or right (n = 3) atrial sources were localized by PL with AUC = 0.85, sensitivity 100%, PPV 30%, and negative predictive value 100%. Spectral DF provided AUC = 0.79. Notably, PL did not comigrate with diagnosis of paroxysmal or persistent AF (P = NS), unlike ECG DF. The novel metric of ECG PL identifies patients with fewer (≤3) or greater numbers of stable rotors/focal sources for AF, validated by intracardiac FIRM mapping, and localized them to right or left atria. These data open the possibility of using 12-lead ECG analyses to classify AF mechanistically and plan procedures for right- or left-sided FIRM ablation.

Controlling dental enamel-cavity ablation depth with optimized stepping parameters along the focal plane normal using a three axis, numerically controlled picosecond laser.

PubMed

Yuan, Fusong; Lv, Peijun; Wang, Dangxiao; Wang, Lei; Sun, Yuchun; Wang, Yong

2015-02-01

The purpose of this study was to establish a depth-control method in enamel-cavity ablation by optimizing the timing of the focal-plane-normal stepping and the single-step size of a three axis, numerically controlled picosecond laser. Although it has been proposed that picosecond lasers may be used to ablate dental hard tissue, the viability of such a depth-control method in enamel-cavity ablation remains uncertain. Forty-two enamel slices with approximately level surfaces were prepared and subjected to two-dimensional ablation by a picosecond laser. The additive-pulse layer, n, was set to 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70. A three-dimensional microscope was then used to measure the ablation depth, d, to obtain a quantitative function relating n and d. Six enamel slices were then subjected to three dimensional ablation to produce 10 cavities, respectively, with additive-pulse layer and single-step size set to corresponding values. The difference between the theoretical and measured values was calculated for both the cavity depth and the ablation depth of a single step. These were used to determine minimum-difference values for both the additive-pulse layer (n) and single-step size (d). When the additive-pulse layer and the single-step size were set 5 and 45, respectively, the depth error had a minimum of 2.25 μm, and 450 μm deep enamel cavities were produced. When performing three-dimensional ablating of enamel with a picosecond laser, adjusting the timing of the focal-plane-normal stepping and the single-step size allows for the control of ablation-depth error to the order of micrometers.

Wavelet-based identification of DNA focal genomic aberrations from single nucleotide polymorphism arrays

PubMed Central

2011-01-01

Background Copy number aberrations (CNAs) are an important molecular signature in cancer initiation, development, and progression. However, these aberrations span a wide range of chromosomes, making it hard to distinguish cancer related genes from other genes that are not closely related to cancer but are located in broadly aberrant regions. With the current availability of high-resolution data sets such as single nucleotide polymorphism (SNP) microarrays, it has become an important issue to develop a computational method to detect driving genes related to cancer development located in the focal regions of CNAs. Results In this study, we introduce a novel method referred to as the wavelet-based identification of focal genomic aberrations (WIFA). The use of the wavelet analysis, because it is a multi-resolution approach, makes it possible to effectively identify focal genomic aberrations in broadly aberrant regions. The proposed method integrates multiple cancer samples so that it enables the detection of the consistent aberrations across multiple samples. We then apply this method to glioblastoma multiforme and lung cancer data sets from the SNP microarray platform. Through this process, we confirm the ability to detect previously known cancer related genes from both cancer types with high accuracy. Also, the application of this approach to a lung cancer data set identifies focal amplification regions that contain known oncogenes, though these regions are not reported using a recent CNAs detecting algorithm GISTIC: SMAD7 (chr18q21.1) and FGF10 (chr5p12). Conclusions Our results suggest that WIFA can be used to reveal cancer related genes in various cancer data sets. PMID:21569311

Neuroimaging of epilepsy

PubMed Central

Cendes, Fernando; Theodore, William H.; Brinkmann, Benjamin H.; Sulc, Vlastimil; Cascino, Gregory D.

2017-01-01

Imaging is pivotal in the evaluation and management of patients with seizure disorders. Elegant structural neuroimaging with magnetic resonance imaging (MRI) may assist in determining the etiology of focal epilepsy and demonstrating the anatomical changes associated with seizure activity. The high diagnostic yield of MRI to identify the common pathological findings in individuals with focal seizures including mesial temporal sclerosis, vascular anomalies, low-grade glial neoplasms and malformations of cortical development has been demonstrated. Positron emission tomography (PET) is the most commonly performed interictal functional neuroimaging technique that may reveal a focal hypometabolic region concordant with seizure onset. Single photon emission computed tomography (SPECT) studies may assist performance of ictal neuroimaging in patients with pharmacoresistant focal epilepsy being considered for neurosurgical treatment. This chapter highlights neuroimaging developments and innovations, and provides a comprehensive overview of the imaging strategies used to improve the care and management of people with epilepsy. PMID:27430454

BER Analysis of Coherent Free-Space Optical Communication Systems with a Focal-Plane-Based Wavefront Sensor

NASA Astrophysics Data System (ADS)

Cao, Jingtai; Zhao, Xiaohui; Liu, Wei; Gu, Haijun

2018-03-01

A wavefront sensor is one of most important units for an adaptive optics system. Based on our previous works, in this paper, we discuss the bit-error-rate (BER) performance of coherent free space optical communication systems with a focal-plane-based wavefront sensor. Firstly, the theory of a focal-plane-based wavefront sensor is given. Then the relationship between the BER and the mixing efficiency with a homodyne receiver is discussed on the basis of binary-phase-shift-keying (BPSK) modulation. Finally, the numerical simulation results are shown that the BER will be decreased obviously after aberrations correction with the focal-plane-based wavefront sensor. In addition, the BER will decrease along with increasing number of photons received within a single bit. These analysis results will provide a reference for the design of the coherent Free space optical communication (FSOC) system.

Measuring chromatic aberrations in imaging systems using plasmonic nanoparticles.

PubMed

Gennaro, Sylvain D; Roschuk, Tyler R; Maier, Stefan A; Oulton, Rupert F

2016-04-01

We demonstrate a method to measure chromatic aberrations of microscope objectives with metallic nanoparticles using white light. Extinction spectra are recorded while scanning a single nanoparticle through a lens's focal plane. We show a direct correlation between the focal wavelength and the longitudinal chromatic focal shift through our analysis of the variations between the scanned extinction spectra at each scan position and the peak extinction over the entire scan. The method has been tested on achromat and apochromat objectives using aluminum disks varying in size from 260-520 nm. Our method is straightforward, robust, low cost, and broadband with a sensitivity suitable for assessing longitudinal chromatic aberrations in high-numerical-aperture apochromatic corrected lenses.

Variable focal length deformable mirror

DOEpatents

Headley, Daniel [Albuquerque, NM; Ramsey, Marc [Albuquerque, NM; Schwarz, Jens [Albuquerque, NM

2007-06-12

A variable focal length deformable mirror has an inner ring and an outer ring that simply support and push axially on opposite sides of a mirror plate. The resulting variable clamping force deforms the mirror plate to provide a parabolic mirror shape. The rings are parallel planar sections of a single paraboloid and can provide an on-axis focus, if the rings are circular, or an off-axis focus, if the rings are elliptical. The focal length of the deformable mirror can be varied by changing the variable clamping force. The deformable mirror can generally be used in any application requiring the focusing or defocusing of light, including with both coherent and incoherent light sources.

Focal nodular hyperplasia with major sinusoidal dilatation: a misleading entity

PubMed Central

Laumonier, Hervé; Frulio, Nora; Laurent, Christophe; Balabaud, Charles; Zucman-Rossi, Jessica; Bioulac-Sage, Paulette

2010-01-01

Focal nodular hyperplasia (FNH) is a benign liver lesion thought to be a non-specific response to locally increased blood flow. Although the diagnosis of FNH and hepatocellular adenoma (HCA) has made great progress over the last few years using modern imaging techniques, there are still in daily practice some difficulties concerning some atypical nodules. Here, the authors report the case of a 47-year-old woman with a single liver lesion thought to be, by imaging, an inflammatory HCA with major sinusoidal congestion. This nodule was revealed to be, at the microscopical level and after specific immunostaining and molecular analysis, an FNH with sinusoidal dilatation (so-called telangiectatic focal nodular hyperplasia). PMID:22798311

Ejection of small droplet from microplate using focused ultrasound

NASA Astrophysics Data System (ADS)

Tanaka, Hiroki; Mizuno, Yosuke; Nakamura, Kentaro

2017-08-01

We discussed an ultrasonic system for single-droplet ejection from a microplate, which is one of the basic and important procedures in the noncontact handling of droplets in air. In this system, a 1.5 MHz concave transducer located below the microplate is used for chasing the liquid surface through a pulse echo method, and also for the ejection of a 1 µL single droplet by the burst of focused ultrasound. We investigated the relationship between the droplet ejection characteristics, the distance from the transducer to the surface of liquid, the material property, and the excitation condition of the focused ultrasonic transducer. It was verified that the optimal position of the transducer was off the focal point of sound pressure by ±1 mm, because the sound intensity had to be controlled to eject a single droplet. Subsequently, we confirmed experimentally that the ejected droplet volume linearly depended on the surface tension of the liquid, and that the droplet volume and ejection velocity were determined by the Webber number, Reynolds number, and Ohnesolge number. In addition, by optimizing the duration of the burst ultrasound, the droplet volume and ejection velocity were controlled.

An In Vivo Lapine Model for Impact-Induced Injury and Osteoarthritic Degeneration of Articular Cartilage

PubMed Central

Alexander, Peter G.; McCarron, Jesse A.; Levine, Matthew J.; Melvin, Gary M.; Murray, Patrick J.; Manner, Paul A.

2012-01-01

Objective: In this study, we applied a spring-loaded impactor to deliver traumatic forces to articular cartilage in vivo. Based on our recent finding that a 0.28-J impact induces maximal catabolic response in adult bovine articular cartilage in vitro using this device, we hypothesize that this impact will induce the formation of a focal osteoarthritic defect in vivo. Design: The femoral condyle of New Zealand White rabbits was exposed and one of the following procedures performed: 0.28 J impact, anterior cruciate ligament transection, articular surface grooving, or no joint or cartilage destruction (control). After 24 hours, 4 weeks, or 12 weeks (n = 3 for each time point), wounds were localized with India ink, and tissue samples were collected and characterized histomorphometrically with Safranin O/Fast green staining and Hoechst 33342 nuclear staining for cell vitality. Results: The spring-loaded device delivered reproducible impacts with the following characteristics: impact area of 1.39 ± 0.11 mm2, calculated load of 326 ± 47.3 MPa, time-to-peak of 0.32 ± 0.03 ms, and an estimated maximal displacement of 25.1% ± 4.5% at the tip apex. The impact resulted in immediate cartilage fissuring and cell loss in the surface and intermediate zones, and it induced the formation of a focal lesion at 12 weeks. The degeneration was defined and appeared more slowly than after anterior cruciate ligament transection, and more pronounced and characteristic than after grooving. Conclusion: A single traumatic 0.28 J impact delivered with this spring-loaded impactor induces focal cartilage degeneration characteristic of osteoarthritis. PMID:26069642

An information-theoretic approach to designing the plane spacing for multifocal plane microscopy

PubMed Central

Tahmasbi, Amir; Ram, Sripad; Chao, Jerry; Abraham, Anish V.; Ward, E. Sally; Ober, Raimund J.

2015-01-01

Multifocal plane microscopy (MUM) is a 3D imaging modality which enables the localization and tracking of single molecules at high spatial and temporal resolution by simultaneously imaging distinct focal planes within the sample. MUM overcomes the depth discrimination problem of conventional microscopy and allows high accuracy localization of a single molecule in 3D along the z-axis. An important question in the design of MUM experiments concerns the appropriate number of focal planes and their spacings to achieve the best possible 3D localization accuracy along the z-axis. Ideally, it is desired to obtain a 3D localization accuracy that is uniform over a large depth and has small numerical values, which guarantee that the single molecule is continuously detectable. Here, we address this concern by developing a plane spacing design strategy based on the Fisher information. In particular, we analyze the Fisher information matrix for the 3D localization problem along the z-axis and propose spacing scenarios termed the strong coupling and the weak coupling spacings, which provide appropriate 3D localization accuracies. Using these spacing scenarios, we investigate the detectability of the single molecule along the z-axis and study the effect of changing the number of focal planes on the 3D localization accuracy. We further review a software module we recently introduced, the MUMDesignTool, that helps to design the plane spacings for a MUM setup. PMID:26113764

Surface geometry and optical aberrations of ex-vivo crystalline lenses

NASA Astrophysics Data System (ADS)

Bueno, Juan M.; Schwarz, Christina; Acosta, Eva; Artal, Pablo

2010-02-01

The shape of the surfaces of ex-vivo human crystalline lenses was measured using a shadow photography technique. From these data, the back-focal distance and the contribution of each surface to the main optical aberrations of the lenses were estimated. The aberrations of the lenses were measured separately with two complementary techniques: a Hartmann-Shack wavefront sensor and a point-diffraction interferometer. A laser scanning set-up was also used to measure the actual back-focal length as well as the phase aberration in one meridian section of the lenses. Measured and predicted back-focal length agreed well within the experimental errors. The lens aberrations computed with a ray-tracing approach from the measured surfaces and geometrical data only reproduce quantitatively the measured aberrations.

Enhanced cryopreservation of MSCs in microfluidic bioreactor by regulated shear flow

PubMed Central

Bissoyi, Akalabya; Bit, Arindam; Singh, Bikesh Kumar; Singh, Abhishek Kumar; Patra, Pradeep Kumar

2016-01-01

Cell-matrix systems can be stored for longer period of time by means of cryopreservation. Cell-matrix and cell-cell interaction has been found to be critical in a number of basic biological processes. Tissue structure maintenance, cell secretary activity, cellular migration, and cell-cell communication all exist because of the presence of cell interactions. This complex and co-ordinated interaction between cellular constituents, extracellular matrix and adjacent cells has been identified as a significant contributor in the overall co-ordination of tissue. The prime objective of this investigation is to evaluate the effects of shear-stress and cell-substrate interaction in successful recovery of adherent human mesenchymal-stem-cells (hMSCs). A customized microfluidic bioreactor has been used for the purpose. We have measured the changes in focal-point-adhesion (FPAs) by changing induced shear stress inside the bioreactor. The findings indicate that with increase in shear stress, FPAs increases between substrate and MSCs. Further, experimental results show that increased FPAs (4e-3 μbar) enhances the cellular survivability of adherent MSCs. Probably, for the first time involvement of focal point interaction in the outcome of cryopreservation of MSCs has been clarified, and it proved a potentially new approach for modification of cryopreservation protocol by up-regulating focal point of cells to improve its clinical application. PMID:27748463

Real-time method for motion-compensated MR thermometry and MRgHIFU treatment in abdominal organs.

PubMed

Celicanin, Zarko; Auboiroux, Vincent; Bieri, Oliver; Petrusca, Lorena; Santini, Francesco; Viallon, Magalie; Scheffler, Klaus; Salomir, Rares

2014-10-01

Magnetic resonance-guided high-intensity focused ultrasound is considered to be a promising treatment for localized cancer in abdominal organs such as liver, pancreas, or kidney. Abdominal motion, anatomical arrangement, and required sustained sonication are the main challenges. MR acquisition consisted of thermometry performed with segmented gradient-recalled echo echo-planar imaging, and a segment-based one-dimensional MR navigator parallel to the main axis of motion to track the organ motion. This tracking information was used in real-time for: (i) prospective motion correction of MR thermometry and (ii) HIFU focal point position lock-on target. Ex vivo experiments were performed on a sheep liver and a turkey pectoral muscle using a motion demonstrator, while in vivo experiments were conducted on two sheep liver. Prospective motion correction of MR thermometry yielded good signal-to-noise ratio (range, 25 to 35) and low geometric distortion due to the use of segmented EPI. HIFU focal point lock-on target yielded isotropic in-plane thermal build-up. The feasibility of in vivo intercostal liver treatment was demonstrated in sheep. The presented method demonstrated in moving phantoms and breathing sheep accurate motion-compensated MR thermometry and precise HIFU focal point lock-on target using only real-time pencil-beam navigator tracking information, making it applicable without any pretreatment data acquisition or organ motion modeling. Copyright © 2013 Wiley Periodicals, Inc.

Combining PALM and SOFI for quantitative imaging of focal adhesions in living cells

NASA Astrophysics Data System (ADS)

Deschout, Hendrik; Lukes, Tomas; Sharipov, Azat; Feletti, Lely; Lasser, Theo; Radenovic, Aleksandra

2017-02-01

Focal adhesions are complicated assemblies of hundreds of proteins that allow cells to sense their extracellular matrix and adhere to it. Although most focal adhesion proteins have been identified, their spatial organization in living cells remains challenging to observe. Photo-activated localization microscopy (PALM) is an interesting technique for this purpose, especially since it allows estimation of molecular parameters such as the number of fluorophores. However, focal adhesions are dynamic entities, requiring a temporal resolution below one minute, which is difficult to achieve with PALM. In order to address this problem, we merged PALM with super-resolution optical fluctuation imaging (SOFI) by applying both techniques to the same data. Since SOFI tolerates an overlap of single molecule images, it can improve the temporal resolution compared to PALM. Moreover, an adaptation called balanced SOFI (bSOFI) allows estimation of molecular parameters, such as the fluorophore density. We therefore performed simulations in order to assess PALM and SOFI for quantitative imaging of dynamic structures. We demonstrated the potential of our PALM-SOFI concept as a quantitative imaging framework by investigating moving focal adhesions in living cells.

7 CFR 3800.3 - Functions.

Code of Federal Regulations, 2013 CFR

2013-01-01

.... (c) Weather and climate. (1) Serve as a focal point within the Department for coordination of weather, climate, and related crop monitoring activities. (d) Remote sensing. (1) Provide technical assistance...

7 CFR 3800.3 - Functions.

Code of Federal Regulations, 2011 CFR

2011-01-01

.... (c) Weather and climate. (1) Serve as a focal point within the Department for coordination of weather, climate, and related crop monitoring activities. (d) Remote sensing. (1) Provide technical assistance...

7 CFR 3800.3 - Functions.

Code of Federal Regulations, 2014 CFR

2014-01-01

.... (c) Weather and climate. (1) Serve as a focal point within the Department for coordination of weather, climate, and related crop monitoring activities. (d) Remote sensing. (1) Provide technical assistance...

7 CFR 3800.3 - Functions.

Code of Federal Regulations, 2012 CFR

2012-01-01

.... (c) Weather and climate. (1) Serve as a focal point within the Department for coordination of weather, climate, and related crop monitoring activities. (d) Remote sensing. (1) Provide technical assistance...

Homogeneity of Moral Judgment? Apprentices Solving Business Conflicts.

ERIC Educational Resources Information Center

Beck, Klaus; Heinrichs, Karin; Minnameier, Gerhard; Parche-Kawik, Kirsten

In an ongoing longitudinal study that started in 1994, the moral development of business apprentices is being studied. The focal point of this project is a critical analysis of L. Kohlberg's thesis of homogeneity, according to which people should judge every moral issue from the point of view of their "modal" stage (the most frequently…

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bahk, Seung-Whan; Dorrer, Christophe; Bromage, Jake

Two-dimensional chromatic aberrations are characterized by a single-shot scheme based on a simultaneous measurement of chromatically diversified focal spots. The chromatic diversity is introduced by a 2-D grating with holographic defocus terms. The chromatic aberrations in the beam are either subtracted or added by the additional known chromatic aberrations in the grating, depending on the diffraction order. By analyzing the asymmetry in the size of diffracted focal spots, input beam chromatic aberrations can be deduced. Theoretical discussions and experimental results are also presented.

Stereo Cloud Height and Wind Determination Using Measurements from a Single Focal Plane

NASA Astrophysics Data System (ADS)

Demajistre, R.; Kelly, M. A.

2014-12-01

We present here a method for extracting cloud heights and winds from an aircraft or orbital platform using measurements from a single focal plane, exploiting the motion of the platform to provide multiple views of the cloud tops. To illustrate this method we use data acquired during aircraft flight tests of a set of simple stereo imagers that are well suited to this purpose. Each of these imagers has three linear arrays on the focal plane, one looking forward, one looking aft, and one looking down. Push-broom images from each of these arrays are constructed, and then a spatial correlation analysis is used to deduce the delays and displacements required for wind and cloud height determination. We will present the algorithms necessary for the retrievals, as well as the methods used to determine the uncertainties of the derived cloud heights and winds. We will apply the retrievals and uncertainty determination to a number of image sets acquired by the airborne sensors. We then generalize these results to potential space based observations made by similar types of sensors.

Magnetic electroanatomical mapping for ablation of focal atrial tachycardias.

PubMed

Marchlinski, F; Callans, D; Gottlieb, C; Rodriguez, E; Coyne, R; Kleinman, D

1998-08-01

Uniform success for ablation of focal atrial tachycardias has been difficult to achieve using standard catheter mapping and ablation techniques. In addition, our understanding of the complex relationship between atrial anatomy, electrophysiology, and surface ECG P wave morphology remains primitive. The magnetic electroanatomical mapping and display system (CARTO) offers an on-line display of electrical activation and/or signal amplitude related to the anatomical location of the recorded sites in the mapped chamber. A window of electrical interest is established based on signals timed from an electrical reference that usually represents a fixed electrogram recording from the coronary sinus or the atrial appendage. This window of electrical interest is established to include atrial activation prior to the onset of the P wave activity associated with the site of origin of a focal atrial tachycardia. Anatomical and electrical landmarks are defined with limited fluoroscopic imaging support and more detailed global chamber and more focal atrial mapping can be performed with minimal fluoroscopic guidance. A three-dimensional color map representing atrial activation or voltage amplitude at the magnetically defined anatomical sites is displayed with on-line data acquisition. This display can be manipulated to facilitate viewing from any angle. Altering the zoom control, triangle fill threshold, clipping plane, or color range can all enhance the display of a more focal area of interest. We documented the feasibility of using this single mapping catheter technique for localizing and ablating focal atrial tachycardias. In a consecutive series of 8 patients with 9 focal atrial tachycardias, the use of the single catheter CARTO mapping system was associated with ablation success in all but one patient who had a left atrial tachycardia localized to the medial aspect of the orifice of the left atrial appendage. Only low power energy delivery was used in this patient because of the unavailability of temperature monitoring in the early version of the Navistar catheter, the location of the arrhythmia, and the history of arrhythmia control with flecainide. No attempt was made to limit fluoroscopy time in our study population. Nevertheless, despite data acquisition from 120-320 anatomically distinct sites during global and more detailed focal atrial mapping, total fluoroscopy exposure was typically < 30 minutes and was as little as 12 minutes. The detailed display capabilities of the CARTO system appear to offer the potential of enhancing our understanding of atrial anatomy, atrial activation, and their relationship to surface ECG P wave morphology during focal atrial tachycardias.

RESPONSE LATENCIES OF NORMAL AND FOCAL-HEAD IRRADIATED MONKEYS

DOE Office of Scientific and Technical Information (OSTI.GOV)

McDowell, A.A.; Brown, W.L.

1963-12-01

This study was designed to determine whether focal-head irradiated rhesus monkeys differ from normal monkeys in a manner analogous to that previously found in whole-body irradiated monkeys with respect to response latencies under both familiar and novel stimulus conditions. Five control and four focal-head irradiated rhesus monkeys with nearly identical training histories were used; the latter were survivors of a focal-head irradiation study conducted four years earlier. They had received 3000 r x radiation to the inferior parietal lobule and posterior aspect of the temporal lobe of the brain, and 30 days later the same dosage to the same areamore » of the brain. The testing was conducted in a modified version of the Wisconsin General Test Apparatus, with 24 trials per day for two days, on response latency to a single food-rewarded wooden block placed randomly over either of the two extreme food-well positions. Then, 24 trials were conducted per day for two days on response latency to either the same food-rewarded wooden block or to a novel nonrewarded wooden block presented simultaneously. On the single-block condition, median response latencies of the two groups were comparable and the groups improved in a similar manner with practice. Optimal performance latencies were also comparable for the two groups. When the novel nonrewarded stimulus block was introduced, both groups manifested comparable disruption of median response latencies, but disruption of optimal response latencies was shown only by the focalhead irradiated group. The findings show that monkeys with previous focal-head irradiation of the posterior association areas, unlike relatively high-dose whole-body irradiated monkeys, manifest median response latencies comparable to those of controls. These data indicate the lasting effects of focal-head irradiation with x rays, and suggest that the sites of permanent damage for monkeys given sublethal whole-body radiation exposure differ from the sites irradiated in the present subjects. (BBB)« less

Method for measuring the focal spot size of an x-ray tube using a coded aperture mask and a digital detector.

PubMed

Russo, Paolo; Mettivier, Giovanni

2011-04-01

The goal of this study is to evaluate a new method based on a coded aperture mask combined with a digital x-ray imaging detector for measurements of the focal spot sizes of diagnostic x-ray tubes. Common techniques for focal spot size measurements employ a pinhole camera, a slit camera, or a star resolution pattern. The coded aperture mask is a radiation collimator consisting of a large number of apertures disposed on a predetermined grid in an array, through which the radiation source is imaged onto a digital x-ray detector. The method of the coded mask camera allows one to obtain a one-shot accurate and direct measurement of the two dimensions of the focal spot (like that for a pinhole camera) but at a low tube loading (like that for a slit camera). A large number of small apertures in the coded mask operate as a "multipinhole" with greater efficiency than a single pinhole, but keeping the resolution of a single pinhole. X-ray images result from the multiplexed output on the detector image plane of such a multiple aperture array, and the image of the source is digitally reconstructed with a deconvolution algorithm. Images of the focal spot of a laboratory x-ray tube (W anode: 35-80 kVp; focal spot size of 0.04 mm) were acquired at different geometrical magnifications with two different types of digital detector (a photon counting hybrid silicon pixel detector with 0.055 mm pitch and a flat panel CMOS digital detector with 0.05 mm pitch) using a high resolution coded mask (type no-two-holes-touching modified uniformly redundant array) with 480 0.07 mm apertures, designed for imaging at energies below 35 keV. Measurements with a slit camera were performed for comparison. A test with a pinhole camera and with the coded mask on a computed radiography mammography unit with 0.3 mm focal spot was also carried out. The full width at half maximum focal spot sizes were obtained from the line profiles of the decoded images, showing a focal spot of 0.120 mm x 0.105 mm at 35 kVp and M = 6.1, with a detector entrance exposure as low as 1.82 mR (0.125 mA s tube load). The slit camera indicated a focal spot of 0.112 mm x 0.104 mm at 35 kVp and M = 3.15, with an exposure at the detector of 72 mR. Focal spot measurements with the coded mask could be performed up to 80 kVp. Tolerance to angular misalignment with the reference beam up to 7 degrees in in-plane rotations and 1 degrees deg in out-of-plane rotations was observed. The axial distance of the focal spot from the coded mask could also be determined. It is possible to determine the beam intensity via measurement of the intensity of the decoded image of the focal spot and via a calibration procedure. Coded aperture masks coupled to a digital area detector produce precise determinations of the focal spot of an x-ray tube with reduced tube loading and measurement time, coupled to a large tolerance in the alignment of the mask.

Three-dimensional particle tracking via tunable color-encoded multiplexing.

PubMed

Duocastella, Martí; Theriault, Christian; Arnold, Craig B

2016-03-01

We present a novel 3D tracking approach capable of locating single particles with nanometric precision over wide axial ranges. Our method uses a fast acousto-optic liquid lens implemented in a bright field microscope to multiplex light based on color into different and selectable focal planes. By separating the red, green, and blue channels from an image captured with a color camera, information from up to three focal planes can be retrieved. Multiplane information from the particle diffraction rings enables precisely locating and tracking individual objects up to an axial range about 5 times larger than conventional single-plane approaches. We apply our method to the 3D visualization of the well-known coffee-stain phenomenon in evaporating water droplets.

Emergency Operations Center

EPA Pesticide Factsheets

EOC serves as the response operational focal point. A communication and coordination hub designed to increase data management and coordination abilities, provides communication support for Watch Officer, Homeland Security, regional and field assets.

Target isolation system, high power laser and laser peening method and system using same

DOEpatents

Dane, C. Brent; Hackel, Lloyd A.; Harris, Fritz

2007-11-06

A system for applying a laser beam to work pieces, includes a laser system producing a high power output beam. Target delivery optics are arranged to deliver the output beam to a target work piece. A relay telescope having a telescope focal point is placed in the beam path between the laser system and the target delivery optics. The relay telescope relays an image between an image location near the output of the laser system and an image location near the target delivery optics. A baffle is placed at the telescope focal point between the target delivery optics and the laser system to block reflections from the target in the target delivery optics from returning to the laser system and causing damage.

Apparatus for and method of performing spectroscopic analysis on an article

DOEpatents

Powell, George Louis; Hallman, Jr., Russell Louis

1999-01-01

An apparatus for and method of analyzing an article having an entrance and an exit in communication with the entrance. The apparatus comprises: a spectrometer having an emission source with a focal point; a plurality of mirrors; and a detector connected to the spectroscope. The emission source is positioned so that its focal point is substantially coextensive with the entrance of the article. The mirrors comprise: a first mirror positionable adjacent the exit of the article and a second mirror positioned relative to the other of said plurality of mirrors. The first mirror receives scattered emissions exiting the article and substantially collimates the scattered emissions. The second mirror substantially focuses the collimated emissions into a focused emission. The detector receives the focused emission from the mirrors.

Apparatus for and method of performing spectroscopic analysis on an article

DOEpatents

Powell, G.L.; Hallman, R.L. Jr.

1999-04-20

An apparatus and method are disclosed for analyzing an article having an entrance and an exit in communication with the entrance. The apparatus comprises: a spectrometer having an emission source with a focal point; a plurality of mirrors; and a detector connected to the spectroscope. The emission source is positioned so that its focal point is substantially coextensive with the entrance of the article. The mirrors comprise: a first mirror positionable adjacent the exit of the article and a second mirror positioned relative to the other of said plurality of mirrors. The first mirror receives scattered emissions exiting the article and substantially collimates the scattered emissions. The second mirror substantially focuses the collimated emissions into a focused emission. The detector receives the focused emission from the mirrors. 6 figs.

HYMOSS signal processing for pushbroom spectral imaging

NASA Technical Reports Server (NTRS)

Ludwig, David E.

1991-01-01

The objective of the Pushbroom Spectral Imaging Program was to develop on-focal plane electronics which compensate for detector array non-uniformities. The approach taken was to implement a simple two point calibration algorithm on focal plane which allows for offset and linear gain correction. The key on focal plane features which made this technique feasible was the use of a high quality transimpedance amplifier (TIA) and an analog-to-digital converter for each detector channel. Gain compensation is accomplished by varying the feedback capacitance of the integrate and dump TIA. Offset correction is performed by storing offsets in a special on focal plane offset register and digitally subtracting the offsets from the readout data during the multiplexing operation. A custom integrated circuit was designed, fabricated, and tested on this program which proved that nonuniformity compensated, analog-to-digital converting circuits may be used to read out infrared detectors. Irvine Sensors Corporation (ISC) successfully demonstrated the following innovative on-focal-plane functions that allow for correction of detector non-uniformities. Most of the circuit functions demonstrated on this program are finding their way onto future IC's because of their impact on reduced downstream processing, increased focal plane performance, simplified focal plane control, reduced number of dewar connections, as well as the noise immunity of a digital interface dewar. The potential commercial applications for this integrated circuit are primarily in imaging systems. These imaging systems may be used for: security monitoring systems, manufacturing process monitoring, robotics, and for spectral imaging when used in analytical instrumentation.

HYMOSS signal processing for pushbroom spectral imaging

NASA Astrophysics Data System (ADS)

Ludwig, David E.

1991-06-01

The objective of the Pushbroom Spectral Imaging Program was to develop on-focal plane electronics which compensate for detector array non-uniformities. The approach taken was to implement a simple two point calibration algorithm on focal plane which allows for offset and linear gain correction. The key on focal plane features which made this technique feasible was the use of a high quality transimpedance amplifier (TIA) and an analog-to-digital converter for each detector channel. Gain compensation is accomplished by varying the feedback capacitance of the integrate and dump TIA. Offset correction is performed by storing offsets in a special on focal plane offset register and digitally subtracting the offsets from the readout data during the multiplexing operation. A custom integrated circuit was designed, fabricated, and tested on this program which proved that nonuniformity compensated, analog-to-digital converting circuits may be used to read out infrared detectors. Irvine Sensors Corporation (ISC) successfully demonstrated the following innovative on-focal-plane functions that allow for correction of detector non-uniformities. Most of the circuit functions demonstrated on this program are finding their way onto future IC's because of their impact on reduced downstream processing, increased focal plane performance, simplified focal plane control, reduced number of dewar connections, as well as the noise immunity of a digital interface dewar. The potential commercial applications for this integrated circuit are primarily in imaging systems. These imaging systems may be used for: security monitoring systems, manufacturing process monitoring, robotics, and for spectral imaging when used in analytical instrumentation.

One-step cartilage repair in the knee: collagen-covered microfracture and autologous bone marrow concentrate. A pilot study.

PubMed

Enea, D; Cecconi, S; Calcagno, S; Busilacchi, A; Manzotti, S; Gigante, A

2015-01-01

Different single-stage surgical approaches are currently under evaluation to repair cartilage focal lesions. To date, only little is known on even short-term clinical follow-up and almost no knowledge exists on histological results of such treatments. The present paper aims to analyze the clinical and histological results of the collagen-covered microfracture and bone marrow concentrate (C-CMBMC) technique in the treatment of focal condylar lesions of knee articular cartilage. Nine patients with focal lesions of the condylar articular cartilage were consecutively treated with arthroscopic microfractures (MFX) covered with a collagen membrane immersed in autologous bone marrow concentrate (BMC) from the iliac crest. Patients were retrospectively assessed using several standardized outcome assessment tools and MRI scans. Four patients consented to undergo second look arthroscopy and biopsy harvest. Every patient was arthroscopically treated for a focal condylar lesion (mean area 2.5 SD(0.4) cm(2)). All the patients (mean age 43 SD(9) years) but one experienced a significant clinical improvement from the pre-operative condition to the latest follow-up (mean 29 SD(11) months). Cartilage macroscopic assessment at 12 months revealed that all the repairs appeared almost normal. Histological analysis showed a hyaline-like cartilage repair in one lesion, a fibrocartilaginous repair in two lesions and a mixture of both in one lesion. The first clinical experience with single-stage C-CMBMC for focal cartilage defects in the knee suggests that it is safe, it improves the short-term knee function and that it has the potential to recreate hyaline-like cartilage. Copyright © 2014. Published by Elsevier B.V.

SIRTF Focal Plane Survey: A Pre-flight Error Analysis

NASA Technical Reports Server (NTRS)

Bayard, David S.; Brugarolas, Paul B.; Boussalis, Dhemetrios; Kang, Bryan H.

2003-01-01

This report contains a pre-flight error analysis of the calibration accuracies expected from implementing the currently planned SIRTF focal plane survey strategy. The main purpose of this study is to verify that the planned strategy will meet focal plane survey calibration requirements (as put forth in the SIRTF IOC-SV Mission Plan [4]), and to quantify the actual accuracies expected. The error analysis was performed by running the Instrument Pointing Frame (IPF) Kalman filter on a complete set of simulated IOC-SV survey data, and studying the resulting propagated covariances. The main conclusion of this study is that the all focal plane calibration requirements can be met with the currently planned survey strategy. The associated margins range from 3 to 95 percent, and tend to be smallest for frames having a 0.14" requirement, and largest for frames having a more generous 0.28" (or larger) requirement. The smallest margin of 3 percent is associated with the IRAC 3.6 and 5.8 micron array centers (frames 068 and 069), and the largest margin of 95 percent is associated with the MIPS 160 micron array center (frame 087). For pointing purposes, the most critical calibrations are for the IRS Peakup sweet spots and short wavelength slit centers (frames 019, 023, 052, 028, 034). Results show that these frames are meeting their 0.14" requirements with an expected accuracy of approximately 0.1", which corresponds to a 28 percent margin.

Focal Point Theory Models for Dissecting Dynamic Duality Problems of Microbial Infections

PubMed Central

Huang, S.-H.; Zhou, W.; Jong, A.

2008-01-01

Extending along the dynamic continuum from conflict to cooperation, microbial infections always involve symbiosis (Sym) and pathogenesis (Pat). There exists a dynamic Sym-Pat duality (DSPD) in microbial infection that is the most fundamental problem in infectomics. DSPD is encoded by the genomes of both the microbes and their hosts. Three focal point (FP) theory-based game models (pure cooperative, dilemma, and pure conflict) are proposed for resolving those problems. Our health is associated with the dynamic interactions of three microbial communities (nonpathogenic microbiota (NP) (Cooperation), conditional pathogens (CP) (Dilemma), and unconditional pathogens (UP) (Conflict)) with the hosts at different health statuses. Sym and Pat can be quantitated by measuring symbiotic index (SI), which is quantitative fitness for the symbiotic partnership, and pathogenic index (PI), which is quantitative damage to the symbiotic partnership, respectively. Symbiotic point (SP), which bears analogy to FP, is a function of SI and PI. SP-converting and specific pathogen-targeting strategies can be used for the rational control of microbial infections. PMID:18350122

Quiet is the new loud: pausing and focus in child and adult Dutch.

PubMed

Romøren, Anna Sara H; Chen, Aoju

2015-03-01

In a number of languages, prosody is used to highlight new information (or focus). In Dutch, focus is marked by accentuation, whereby focal constituents are accented and post-focal constituents are de-accented. Even if pausing is not traditionally seen as a cue to focus in Dutch, several previous studies have pointed to a possible relationship between pausing and information structure. Considering that Dutch-speaking 4 to 5 year olds are not yet completely proficient in using accentuation for focus and that children generally pause more than adults, we asked whether pausing might be an available parameter for children to manipulate for focus. Sentences with varying focus structure were elicited from 10 Dutch-speaking 4 to 5 year olds and 9 Dutch-speaking adults by means of a picture-matching game. Comparing pause durations before focal and non-focal targets showed pre-target pauses to be significantly longer when the targets were focal than when they were not. Notably, the use of pausing was more robust in the children than in the adults, suggesting that children exploit pausing to mark focus more generally than adults do, at a stage where their mastery of the canonical cues to focus is still developing.

Status of the Correlation Process of the V-HAB Simulation with Ground Tests and ISS Telemetry Data

NASA Technical Reports Server (NTRS)

Ploetner, P.; Roth, C.; Zhukov, A.; Czupalla, M.; Anderson, M.; Ewert, M.

2013-01-01

The Virtual Habitat (V-HAB) is a dynamic Life Support System (LSS) simulation, created for investigation of future human spaceflight missions. It provides the capability to optimize LSS during early design phases. The focal point of the paper is the correlation and validation of V-HAB against ground test and flight data. In order to utilize V-HAB to design an Environmental Control and Life Support System (ECLSS) it is important to know the accuracy of simulations, strengths and weaknesses. Therefore, simulations of real systems are essential. The modeling of the International Space Station (ISS) ECLSS in terms of single technologies as well as an integrated system and correlation against ground and flight test data is described. The results of the simulations make it possible to prove the approach taken by V-HAB.

Multifocus confocal Raman microspectroscopy for fast multimode vibrational imaging of living cells.

PubMed

Okuno, Masanari; Hamaguchi, Hiro-o

2010-12-15

We have developed a multifocus confocal Raman microspectroscopic system for the fast multimode vibrational imaging of living cells. It consists of an inverted microscope equipped with a microlens array, a pinhole array, a fiber bundle, and a multichannel Raman spectrometer. Forty-eight Raman spectra from 48 foci under the microscope are simultaneously obtained by using multifocus excitation and image-compression techniques. The multifocus confocal configuration suppresses the background generated from the cover glass and the cell culturing medium so that high-contrast images are obtainable with a short accumulation time. The system enables us to obtain multimode (10 different vibrational modes) vibrational images of living cells in tens of seconds with only 1 mW laser power at one focal point. This image acquisition time is more than 10 times faster than that in conventional single-focus Raman microspectroscopy.

SWOT Analysis on Medical Informatics and Development Strategies

ERIC Educational Resources Information Center

Ma, Xiaoyan; Han, Zhongdong; Ma, Hua

2015-01-01

This article aims at clarifying the strategic significance of developing medical informatics, conducting SWOT analysis on this discipline and hence establishing the strategic objectives and focal points for its development.

Learning from an Owl.

ERIC Educational Resources Information Center

Greeves, Adrian

1988-01-01

Describes one creative writing teacher's use of an owl as a focal point for writing activities and how the writing activities aided the students' personal and creative development. Provides samples of student writing. (ARH)

Noninvasive Spatially Offset and Transmission Raman Mapping of Breast Tissue: A Multimodal Approach Towards the In Vivo assessment of Tissue Pathology

DTIC Science & Technology

2013-04-01

liquid nitrogen cooled mercury cadmium telluride ( MCT ) detector and compare their performance to a commercial FT-IR imaging instrument. We examine the...telluride ( MCT ) detector (InfraRed Associates, Stuart, FL), and in a second widefield imaging configuration, we employed a cooled focal plane array (FPA...experiment, a cooled focal plane array (FPA) was substituted for the bolometer. (b) A cooled single-element MCT detector is utilized with an adjustable

Linear summation of outputs in a balanced network model of motor cortex.

PubMed

Capaday, Charles; van Vreeswijk, Carl

2015-01-01

Given the non-linearities of the neural circuitry's elements, we would expect cortical circuits to respond non-linearly when activated. Surprisingly, when two points in the motor cortex are activated simultaneously, the EMG responses are the linear sum of the responses evoked by each of the points activated separately. Additionally, the corticospinal transfer function is close to linear, implying that the synaptic interactions in motor cortex must be effectively linear. To account for this, here we develop a model of motor cortex composed of multiple interconnected points, each comprised of reciprocally connected excitatory and inhibitory neurons. We show how non-linearities in neuronal transfer functions are eschewed by strong synaptic interactions within each point. Consequently, the simultaneous activation of multiple points results in a linear summation of their respective outputs. We also consider the effects of reduction of inhibition at a cortical point when one or more surrounding points are active. The network response in this condition is linear over an approximately two- to three-fold decrease of inhibitory feedback strength. This result supports the idea that focal disinhibition allows linear coupling of motor cortical points to generate movement related muscle activation patterns; albeit with a limitation on gain control. The model also explains why neural activity does not spread as far out as the axonal connectivity allows, whilst also explaining why distant cortical points can be, nonetheless, functionally coupled by focal disinhibition. Finally, we discuss the advantages that linear interactions at the cortical level afford to motor command synthesis.

Optimizing the performance of dual-axis confocal microscopes via Monte-Carlo scattering simulations and diffraction theory.

PubMed

Chen, Ye; Liu, Jonathan T C

2013-06-01

Dual-axis confocal (DAC) microscopy has been found to exhibit superior rejection of out-of-focus and multiply scattered background light compared to conventional single-axis confocal microscopy. DAC microscopes rely on the use of separated illumination and collection beam paths that focus and intersect at a single focal volume (voxel) within tissue. While it is generally recognized that the resolution and contrast of a DAC microscope depends on both the crossing angle of the DAC beams, 2θ, and the focusing numerical aperture of the individual beams, α, a detailed study to investigate these dependencies has not been performed. Contrast and resolution are considered as two main criteria to assess the performance of a point-scanned DAC microscope (DAC-PS) and a line-scanned DAC microscope (DAC-LS) as a function of θ and α. The contrast and resolution of these designs are evaluated by Monte-Carlo scattering simulations and diffraction theory calculations, respectively. These results can be used for guiding the optimal designs of DAC-PS and DAC-LS microscopes.

Tracking and data relay satellite system: NASA's new spacecraft data acquisition system

NASA Astrophysics Data System (ADS)

Schneider, W. C.; Garman, A. A.

The growth in NASA's ground network complexity and cost triggered a search for an alternative. Through a lease service contract, Western Union will provide to NASA 10 years of space communications services with a Tracking and Data Relay Satellite System (TDRSS). A constellation of four operating satellites in geostationary orbit and a single ground terminal will provide complete tracking, telemetry and command service for all of NASA's Earth orbital satellites below an altitude of 12,000 km. The system is shared: two satellites will be dedicated to NASA service; a third will provide backup as a shared spare; the fourth satellite will be dedicated to Western Union's Advanced Westar commercial service. Western Union will operate the ground terminal and provide operational satellite control. NASA's Network Control Center will provide the focal point for scheduling user services and controlling the interface between TDRSS and the rest of the NASA communications network, project control centers and data processing facilities. TDRSS single access user spacecraft data systems should be designed for efficient time shared data relay support. Reimbursement policy and rate structure for non-NASA users are currently being developed.

Dewey's Logic as a Methodological Grounding Point for Practitioner-Based Inquiry

ERIC Educational Resources Information Center

Demetrion, George

2012-01-01

The purpose of this essay is to draw out key insights from Dewey's important text "Logic: The Theory of Inquiry" to provide theoretical and practical support for the emergent field of teacher research. The specific focal point is the argument in Cochran-Smith and Lytle's "Inside/Outside: Teacher Research and Knowledge" on the significance of…

Epidemiological, clinical and genetic aspects of adult onset isolated focal dystonia in Ireland.

PubMed

Williams, L; McGovern, E; Kimmich, O; Molloy, A; Beiser, I; Butler, J S; Molloy, F; Logan, P; Healy, D G; Lynch, T; Walsh, R; Cassidy, L; Moriarty, P; Moore, H; McSwiney, T; Walsh, C; O'Riordan, S; Hutchinson, M

2017-01-01

Adult onset idiopathic isolated focal dystonia presents with a number of phenotypes. Reported prevalence rates vary considerably; well-characterized cohorts are important to our understanding of this disorder. To perform a nationwide epidemiological study of adult onset idiopathic isolated focal dystonia in the Republic of Ireland. Patients with adult onset idiopathic isolated focal dystonia were recruited from multiple sources. Diagnosis was based on assessment by a neurologist with an expertise in movement disorders. When consent was obtained, a number of clinical features including family history were assessed. On the prevalence date there were 592 individuals in Ireland with adult onset idiopathic isolated focal dystonia, a point prevalence of 17.8 per 100 000 (95% confidence interval 16.4-19.2). Phenotype numbers were cervical dystonia 410 (69.2%), blepharospasm 102 (17.2%), focal hand dystonia 39 (6.6%), spasmodic dysphonia 18 (3.0%), musician's dystonia 17 (2.9%) and oromandibular dystonia six (1.0%). Sixty-two (16.5%) of 375 consenting index cases had a relative with clinically confirmed adult onset idiopathic isolated focal dystonia (18 multiplex and 24 duplex families). Marked variations in the proportions of patients with tremor, segmental spread, sensory tricks, pain and psychiatric symptoms by phenotype were documented. The prevalence of adult onset idiopathic isolated focal dystonia in Ireland is higher than that recorded in many similar service-based epidemiological studies but is still likely to be an underestimate. The low proportion of individuals with blepharospasm may reflect reduced environmental exposure to sunlight in Ireland. This study will serve as a resource for international comparative studies of environmental and genetic factors in the pathogenesis of the disorder. © 2016 EAN.

Focal exposure of limited lung volumes to high-dose irradiation down-regulated organ development-related functions and up-regulated the immune response in mouse pulmonary tissues.

PubMed

Kim, Bu-Yeo; Jin, Hee; Lee, Yoon-Jin; Kang, Ga-Young; Cho, Jaeho; Lee, Yun-Sil

2016-01-27

Despite the emergence of stereotactic body radiotherapy (SBRT) for treatment of medically inoperable early-stage non-small-cell lung cancer patients, the molecular effects of focal exposure of limited lung volumes to high-dose radiation have not been fully characterized. This study was designed to identify molecular changes induced by focal high-dose irradiation using a mouse model of SBRT. Central areas of the mouse left lung were focally-irradiated (3 mm in diameter) with a single high-dose of radiation (90 Gy). Temporal changes in gene expression in the irradiated and non-irradiated neighboring lung regions were analyzed by microarray. For comparison, the long-term effect (12 months) of 20 Gy radiation on a diffuse region of lung was also measured. The majority of genes were down-regulated in the focally-irradiated lung areas at 2 to 3 weeks after irradiation. This pattern of gene expression was clearly different than gene expression in the diffuse region of lungs exposed to low-dose radiation. Ontological and pathway analyses indicated these down-regulated genes were mainly associated with organ development. Although the number was small, genes that were up-regulated after focal irradiation were associated with immune-related functions. The temporal patterns of gene expression and the associated biological functions were also similar in non-irradiated neighboring lung regions, although statistical significance was greatly reduced when compared with those from focally-irradiated areas of the lung. From network analysis of temporally regulated genes, we identified inter-related modules associated with diverse functions, including organ development and the immune response, in both the focally-irradiated regions and non-irradiated neighboring lung regions. Focal exposure of lung tissue to high-dose radiation induced expression of genes associated with organ development and the immune response. This pattern of gene expression was also observed in non-irradiated neighboring areas of lung tissue, indicating a global lung response to focal high-dose irradiation.

Short-Lasting Episodes of Torsade de Pointes in the Chronic Atrioventricular Block Dog Model Have a Focal Mechanism, While Longer-Lasting Episodes Are Maintained by Re-Entry.

PubMed

Vandersickel, Nele; Bossu, Alexandre; De Neve, Jan; Dunnink, Albert; Meijborg, Veronique M F; van der Heyden, Marcel A G; Beekman, Jet D M; De Bakker, Jacques M T; Vos, Marc A; Panfilov, Alexander V

2017-12-26

This study investigated the arrhythmogenic mechanisms responsible for torsade de pointes (TdP) in the chronic atrioventricular block dog model, known for its high susceptibility for TdP. The mechanism of TdP arrhythmias has been under debate for many years. Focal activity as well as re-entry have both been mentioned in the initiation and the perpetuation of TdP. In 5 TdP-sensitive chronic atrioventricular block dogs, 56 needle electrodes were evenly distributed transmurally to record 240 unipolar local electrograms simultaneously. Nonterminating (NT) episodes were defibrillated after 10 s. Software was developed to automatically detect activation times and to create 3-dimensional visualizations of the arrhythmia. For each episode of ectopic activity (ranging from 2 beats to NT episodes), a novel methodology was created to construct directed graphs of the wave propagation and detect re-entry loops by using an iterative depth-first-search algorithm. Depending on the TdP definition (number of consecutive ectopic beats), we analyzed 29 to 54 TdP: 29 were longer than 5 beats. In the total group, 9 were NT and 45 were self-terminating. Initiation and termination were always based on focal activity. Re-entry becomes more important in the longer-lasting episodes (>14 beats), whereas in all NT TdP, re-entry was the last active mechanism. During re-entry, excitation fronts were constantly present in the heart, while during focal TdP, there was always a silent interval between 2 consecutive waves (142 ms) during which excitation fronts were absent. Interbeat intervals were significantly smaller for re-entry episodes-220 versus 310 ms in focal. Electrograms recorded in particular areas during NT TdP episodes had significantly smaller amplitude (0.38) than during focal episodes (0.59). TdP can be driven by focal activity as well as by re-entry depending on the duration of the episode. NT episodes are always maintained by re-entry, which can be identified in local unipolar electrograms by shorter interbeat intervals and smaller deflection amplitude. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

High-numerical-aperture-based virtual point detectors for photoacoustic tomography

NASA Astrophysics Data System (ADS)

Li, Changhui; Wang, Lihong V.

2008-07-01

The focal point of a high-numerical-aperture (NA) ultrasonic transducer can be used as a virtual point detector. This virtual point detector detects omnidirectionally over a wide acceptance angle. It also combines a large active transducer surface and a small effective virtual detector size. Thus the sensitivity is high compared with that of a real point detector, and the aperture effect is small compared with that of a finite size transducer. We present two kinds of high-NA-based virtual point detectors and their successful application in photoacoustic tomography. They can also be applied in other ultrasound-related fields.

Regional cerebral blood flow changes associated with focal electrically administered seizure therapy (FEAST).

PubMed

Chahine, George; Short, Baron; Spicer, Ken; Schmidt, Matthew; Burns, Carol; Atoui, Mia; George, Mark S; Sackeim, Harold A; Nahas, Ziad

2014-01-01

Use of electroconvulsive therapy (ECT) is limited by cognitive disturbance. Focal electrically-administered seizure therapy (FEAST) is designed to initiate focal seizures in the prefrontal cortex. To date, no studies have documented the effects of FEAST on regional cerebral blood flow (rCBF). A 72 year old depressed man underwent three single photon emission computed tomography (SPECT) scans to capture the onset and resolution of seizures triggered with right unilateral FEAST. We used Bioimage Suite for within-subject statistical analyses of perfusion differences ictally and post-ictally compared with the baseline scan. Early ictal increases in regional cerebral blood flow (rCBF) were limited to the right prefrontal cortex. Post-ictally, perfusion was reduced in bilateral frontal and occipital cortices and increased in left motor and precuneus cortex. FEAST appears to triggers focal onsets of seizure activity in the right prefrontal cortex with subsequent generalization. Future studies are needed on a larger sample. Copyright © 2014 Elsevier Inc. All rights reserved.

A novel dual-color bifocal imaging system for single-molecule studies.

PubMed

Jiang, Chang; Kaul, Neha; Campbell, Jenna; Meyhofer, Edgar

2017-05-01

In this paper, we report the design and implementation of a dual-color bifocal imaging (DBI) system that is capable of acquiring two spectrally distinct, spatially registered images of objects located in either same or two distinct focal planes. We achieve this by separating an image into two channels with distinct chromatic properties and independently focusing both images onto a single CCD camera. The two channels in our device are registered with subpixel accuracy, and long-term stability of the registered images with nanometer-precision was accomplished by reducing the drift of the images to ∼5 nm. We demonstrate the capabilities of our DBI system by imaging biomolecules labeled with spectrally distinct dyes and micro- and nano-sized spheres located in different focal planes.

Sierra Leone Estuary

NASA Image and Video Library

2014-02-05

This image acquired by NASA Terra spacecraft is of the Sierra Leone estuary, which became a focal point for trade and interaction between Africans and Europeans because of its exceptional harbor, starting in the mid-15th century.

77 FR 66476 - National Advisory Council

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-05

... by teleconference. Members of the public who wish to obtain the listen-only call-in number, access... policies and strategies. FEMA's Office of the NAC serves as the focal point for all NAC coordination...

Training to Survive the Hazard Called Education.

ERIC Educational Resources Information Center

Agassi, Joseph

1984-01-01

The evils of compulsory instruction and the problems of educational reform in the general education system are explored. Strategies which target student boredom as a focal point are offered for improving education. (DF)

Relay telescope for high power laser alignment system

DOEpatents

Dane, C. Brent; Hackel, Lloyd; Harris, Fritz B.

2006-09-19

A laser system includes an optical path having an intracavity relay telescope with a telescope focal point for imaging an output of the gain medium between an image location at or near the gain medium and an image location at or near an output coupler for the laser system. A kinematic mount is provided within a vacuum chamber, and adapted to secure beam baffles near the telescope focal point. An access port on the vacuum chamber is adapted for allowing insertion and removal of the beam baffles. A first baffle formed using an alignment pinhole aperture is used during alignment of the laser system. A second tapered baffle replaces the alignment aperture during operation and acts as a far-field baffle in which off angle beams strike the baffle a grazing angle of incidence, reducing fluence levels at the impact areas.

Poliomyelitis eradication – the review of notifications from the years 2010-2016 sent to National IHR Focal Point

PubMed

Radziszewski, Franciszek; Janiec, Janusz; Henszel, Łukasz; Izdebski, Radosław; Polański, Piotr

Polio eradication programme was launched after World Health Assembly in 1988. Despite considerable decrease in reported cases it still constitutes a significant public health threat. All WHO member state is bound to appoint National IHR Focal Point, which operates based on International Health Regulations (2005), which were enacted during the World Health Assembly in 2005. In Poland National IHR Focal Point (IHR NFP in Poland) operates since 2007, and is located in the Department of Epidemiology, in National Institute of Public Health - National Institute of Hygiene. Its aim is to acquire, assess and to transfer information on events which may constitute an international threat for the public health. IHR NFP in Poland has an access to WHO’s Event Information Site (EIS) as well as Early Warning and Response System (EWRS) with reading-only credentials. Both platforms are of limited access (1). Among recipients of IHR NFP notifications and information are experts from many fields such as epidemiology, virology, bacteriology and others- related to specific type of notification, as well as specific and appointed members of state’s administration and authorities in the field of public health. In this paper a review of notifications on the subject of poliomyelitis, sent to IHR NFP in Poland in the years 2010-2016 is presented, as well as references to poliomyelitis epidemiological situation were made based on the date from Global Polio Eradication Initiative.

Effect on High-Intensity Fields of a Tough Hydrophone With Hydrothermal PZT Thick-Film Vibrator and Titanium Front Layer.

PubMed

Okada, Nagaya; Takeuchi, Shinichi

2017-07-01

A novel tough hydrophone was fabricated by depositing hydrothermally synthesized lead zirconate titanate polycrystalline film on the back-side surface of a titanium plate. Our developed tough hydrophone resisted damage in a high-pressure field (15 MPa) at a focal point of a sinusoidal continuous wave driven by a concave high-intensity focused ultrasound (HIFU) transducer with up to 50 W of power input to the sound source. The hydrophone was suitable for the HIFU field, even though the hydrophone has a flat-shape tip of 3.5 mm diameter, which is slightly larger than the wavelength of a few megahertz. In this paper, experiments are performed to assess the effect on the HIFU field of changing the shape of the tough hydrophone, with the aim of developing a tough hydrophone. The spatial distribution of the acoustic bubbles around the focal point was visualized by using ultrasonic diagnostic equipment with the tough hydrophone located at the focal point of the HIFU transducer. From the visualization, the trapped acoustic bubbles were seen to arise from the standing wave, which implies that the acoustic pressure is reduced by this cloud of acoustic bubbles that appeared during hydrophone measurement. Although cavitation and acoustic bubbles may be unavoidable when using high-intensity ultrasound, the estimated result of evaluating acoustic fields without misunderstanding by acoustic bubbles can be obtained by the aid of visualizing bubbles around the tough hydrophone.

Cassegrain Solar Concentrator System for ISRU Material Processing

NASA Technical Reports Server (NTRS)

Colozza, Anthony J.; Macosko, Robert; Castle, Charles; Sacksteder, Kurt; Suzuki, Nantel H.; Mulherin, James

2012-01-01

A 0.5 m diameter Cassegrain concentrator was constructed as a means of providing highly concentrated sunlight for the demonstration processing of lunar simulated regolith and other NASA In-Situ Resource Utilization Project (ISRU) reaction processes. The concentrator is constructed of aluminum with a concentration ratio of approximately 3000 to 1. The concentrator focuses solar energy into a movable tray located behind the concentrator. This tray can hold simulated regolith or any other material and or device to be tested with concentrated solar energy. The tray is movable in one axis. A 2-axis extended optical system was also designed and fabricated. The extended optical system is added to the back of the primary concentrator in place of the moveable test tray and associated apparatus. With this optical system the focused sunlight can be extended from the back of the primary concentrator toward the ground with the added advantage of moving the focal point axially and laterally relative to the ground. This allows holding the focal point at a fixed position on the ground as the primary concentrator tracks the sun. Also, by design, the focal point size was reduced via the extended optics by a factor of 2 and results in a concentration ratio for the system of approximately 6,000 to 1.The designs of both optical systems are discussed. The results from simulated regolith melting tests are presented as well as the operational experience of utilizing the Cassegrain concentrator system.

Miniature electrically tunable rotary dual-focus lenses

NASA Astrophysics Data System (ADS)

Zou, Yongchao; Zhang, Wei; Lin, Tong; Chau, Fook Siong; Zhou, Guangya

2016-03-01

The emerging dual-focus lenses are drawing increasing attention recently due to their wide applications in both academia and industries, including laser cutting systems, microscopy systems, and interferometer-based surface profilers. In this paper, a miniature electrically tunable rotary dual-focus lens is developed. Such a lens consists of two optical elements, each having an optical flat surface and one freeform surface. The two freeform surfaces are initialized with the governing equation Ar2θ (A is the constant to be determined, r and θ denote the radii and angles in the polar coordinate system) and then optimized by ray tracing technique with additional Zernike polynomial terms for aberration correction. The freeform surfaces are achieved by a single-point diamond turning technique and then a PDMS-based replication process is utilized to materialize the final lens elements. To drive the two coaxial elements to rotate independently, two MEMS thermal rotary actuators are developed and fabricated by a standard MUMPs process. The experimental results show that the MEMS thermal actuator provides a maximum rotation angle of about 8.2 degrees with an input DC voltage of 6.5 V, leading to a wide tuning range for both the two focal lengths of the lens. Specifically, one focal length can be tuned from about 30 mm to 20 mm while the other one can be adjusted from about 30 mm to 60 mm.

Design of a nanopatterned long focal-length planar focusing collector for concentrated solar power

NASA Astrophysics Data System (ADS)

Ding, Qing; Choubal, Aakash; Toussaint, Kimani C.

2017-02-01

Concentrated solar power (CSP) facilities heavily utilize parabolic troughs to collect and concentrate sunlight onto receivers that deliver solar thermal energy to heat engines for generating electricity. However, parabolic troughs are bulky and heavy and result in a large capital investment for CSP plants, thereby making it difficult for CSP technology to be competitive with photovoltaics. We present the design of a planar focusing collector (PFC) with focal length beyond the micron scale. The PFC design is based on the use of a nanostructured silver surface for linearly polarized singlewavelength light. The designed PFC consists of metallic nanogrooves on a dielectric substrate. The geometric properties, namely the width and depth, of a single-unit nanogroove allows for full control of the optical phase at desired spatial coordinates along the nanogroove short-axis for a single wavelength. Moreover, we show numerically that such phase control can be used to construct a phase front that mimics that of a cylindrical lens. In addition, we determine the concentration ratio by comparing the width of our PFC design to the cross-sectional width of its focal spot. We also determine the conversion efficiency at long focal lengths by evaluating the ratio of the collected optical power to the incoming optical power. Finally, we examine the focusing behavior across multiple wavelengths and angles of incidence. Our work shows how nano-optics and plasmonics could contribute to this important area of CSP technology.

Spatial attention is attracted in a sustained fashion toward singular points in the optic flow.

PubMed

Wang, Shuo; Fukuchi, Masaki; Koch, Christof; Tsuchiya, Naotsugu

2012-01-01

While a single approaching object is known to attract spatial attention, it is unknown how attention is directed when the background looms towards the observer as s/he moves forward in a quasi-stationary environment. In Experiment 1, we used a cued speeded discrimination task to quantify where and how spatial attention is directed towards the target superimposed onto a cloud of moving dots. We found that when the motion was expansive, attention was attracted towards the singular point of the optic flow (the focus of expansion, FOE) in a sustained fashion. The effects were less pronounced when the motion was contractive. The more ecologically valid the motion features became (e.g., temporal expansion of each dot, spatial depth structure implied by distribution of the size of the dots), the stronger the attentional effects. Further, the attentional effects were sustained over 1000 ms. Experiment 2 quantified these attentional effects using a change detection paradigm by zooming into or out of photographs of natural scenes. Spatial attention was attracted in a sustained manner such that change detection was facilitated or delayed depending on the location of the FOE only when the motion was expansive. Our results suggest that focal attention is strongly attracted towards singular points that signal the direction of forward ego-motion.

Spatial Attention Is Attracted in a Sustained Fashion toward Singular Points in the Optic Flow

PubMed Central

Wang, Shuo; Fukuchi, Masaki; Koch, Christof; Tsuchiya, Naotsugu

2012-01-01

While a single approaching object is known to attract spatial attention, it is unknown how attention is directed when the background looms towards the observer as s/he moves forward in a quasi-stationary environment. In Experiment 1, we used a cued speeded discrimination task to quantify where and how spatial attention is directed towards the target superimposed onto a cloud of moving dots. We found that when the motion was expansive, attention was attracted towards the singular point of the optic flow (the focus of expansion, FOE) in a sustained fashion. The effects were less pronounced when the motion was contractive. The more ecologically valid the motion features became (e.g., temporal expansion of each dot, spatial depth structure implied by distribution of the size of the dots), the stronger the attentional effects. Further, the attentional effects were sustained over 1000 ms. Experiment 2 quantified these attentional effects using a change detection paradigm by zooming into or out of photographs of natural scenes. Spatial attention was attracted in a sustained manner such that change detection was facilitated or delayed depending on the location of the FOE only when the motion was expansive. Our results suggest that focal attention is strongly attracted towards singular points that signal the direction of forward ego-motion. PMID:22905096

Evaluation of focused ultrasound algorithms: Issues for reducing pre-focal heating and treatment time.

PubMed

Yiannakou, Marinos; Trimikliniotis, Michael; Yiallouras, Christos; Damianou, Christakis

2016-02-01

Due to the heating in the pre-focal field the delay between successive movements in high intensity focused ultrasound (HIFU) are sometimes as long as 60s, resulting to treatment time in the order of 2-3h. Because there is generally a requirement to reduce treatment time, we were motivated to explore alternative transducer motion algorithms in order to reduce pre-focal heating and treatment time. A 1 MHz single element transducer with 4 cm diameter and 10 cm focal length was used. A simulation model was developed that estimates the temperature, thermal dose and lesion development in the pre-focal field. The simulated temperature history that was combined with the motion algorithms produced thermal maps in the pre-focal region. Polyacrylimde gel phantom was used to evaluate the induced pre-focal heating for each motion algorithm used, and also was used to assess the accuracy of the simulation model. Three out of the six algorithms having successive steps close to each other, exhibited severe heating in the pre-focal field. Minimal heating was produced with the algorithms having successive steps apart from each other (square, square spiral and random). The last three algorithms were improved further (with small cost in time), thus eliminating completely the pre-focal heating and reducing substantially the treatment time as compared to traditional algorithms. Out of the six algorithms, 3 were successful in eliminating the pre-focal heating completely. Because these 3 algorithms required no delay between successive movements (except in the last part of the motion), the treatment time was reduced by 93%. Therefore, it will be possible in the future, to achieve treatment time of focused ultrasound therapies shorter than 30 min. The rate of ablated volume achieved with one of the proposed algorithms was 71 cm(3)/h. The intention of this pilot study was to demonstrate that the navigation algorithms play the most important role in reducing pre-focal heating. By evaluating in the future, all commercially available geometries, it will be possible to reduce the treatment time, for thermal ablation protocols intended for oncological targets. Copyright © 2015 Elsevier B.V. All rights reserved.

Using a focal-plane array to estimate antenna pointing errors

NASA Technical Reports Server (NTRS)

Zohar, S.; Vilnrotter, V. A.

1991-01-01

The use of extra collecting horns in the focal plane of an antenna as a means of determining the Direction of Arrival (DOA) of the signal impinging on it, provided it is within the antenna beam, is considered. Our analysis yields a relatively simple algorithm to extract the DOA from the horns' outputs. An algorithm which, in effect, measures the thermal noise of the horns' signals and determines its effect on the uncertainty of the extracted DOA parameters is developed. Both algorithms were implemented in software and tested in simulated data. Based on these tests, it is concluded that this is a viable approach to the DOA determination. Though the results obtained are of general applicability, the particular motivation for the present work is their application to the pointing of a mechanically deformed antenna. It is anticipated that the pointing algorithm developed for a deformed antenna could be obtained as a small perturbation of the algorithm developed for an undeformed antenna. In this context, it should be pointed out that, with a deformed antenna, the array of horns and its associated circuitry constitute the main part of the deformation-compensation system. In this case, the pointing system proposed may be viewed as an additional task carried out by the deformation-compensation hardware.

Acute Traumatic Brain Injury Does Not Exacerbate Amyotrophic Lateral Sclerosis in the SOD1G93A Rat Model1,2,3

PubMed Central

Thomsen, Gretchen M.

2015-01-01

Abstract Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron disease in which upper and lower motor neurons degenerate, leading to muscle atrophy, paralysis, and death within 3 to 5 years of onset. While a small percentage of ALS cases are genetically linked, the majority are sporadic with unknown origin. Currently, etiological links are associated with disease onset without mechanistic understanding. Of all the putative risk factors, however, head trauma has emerged as a consistent candidate for initiating the molecular cascades of ALS. Here, we test the hypothesis that traumatic brain injury (TBI) in the SOD1 G93A transgenic rat model of ALS leads to early disease onset and shortened lifespan. We demonstrate, however, that a one-time acute focal injury caused by controlled cortical impact does not affect disease onset or survival. Establishing the negligible involvement of a single acute focal brain injury in an ALS rat model increases the current understanding of the disease. Critically, untangling a single focal TBI from multiple mild injuries provides a rationale for scientists and physicians to increase focus on repeat injuries to hopefully pinpoint a contributing cause of ALS. PMID:26464984

Seizures and Sleep in the Thalamus: Focal Limbic Seizures Show Divergent Activity Patterns in Different Thalamic Nuclei.

PubMed

Feng, Li; Motelow, Joshua E; Ma, Chanthia; Biche, William; McCafferty, Cian; Smith, Nicholas; Liu, Mengran; Zhan, Qiong; Jia, Ruonan; Xiao, Bo; Duque, Alvaro; Blumenfeld, Hal

2017-11-22

The thalamus plays diverse roles in cortical-subcortical brain activity patterns. Recent work suggests that focal temporal lobe seizures depress subcortical arousal systems and convert cortical activity into a pattern resembling slow-wave sleep. The potential simultaneous and paradoxical role of the thalamus in both limbic seizure propagation, and in sleep-like cortical rhythms has not been investigated. We recorded neuronal activity from the central lateral (CL), anterior (ANT), and ventral posteromedial (VPM) nuclei of the thalamus in an established female rat model of focal limbic seizures. We found that population firing of neurons in CL decreased during seizures while the cortex exhibited slow waves. In contrast, ANT showed a trend toward increased neuronal firing compatible with polyspike seizure discharges seen in the hippocampus. Meanwhile, VPM exhibited a remarkable increase in sleep spindles during focal seizures. Single-unit juxtacellular recordings from CL demonstrated reduced overall firing rates, but a switch in firing pattern from single spikes to burst firing during seizures. These findings suggest that different thalamic nuclei play very different roles in focal limbic seizures. While limbic nuclei, such as ANT, appear to participate directly in seizure propagation, arousal nuclei, such as CL, may contribute to depressed cortical function, whereas sleep spindles in relay nuclei, such as VPM, may interrupt thalamocortical information flow. These combined effects could be critical for controlling both seizure severity and impairment of consciousness. Further understanding of differential effects of seizures on different thalamocortical networks may lead to improved treatments directly targeting these modes of impaired function. SIGNIFICANCE STATEMENT Temporal lobe epilepsy has a major negative impact on quality of life. Previous work suggests that the thalamus plays a critical role in thalamocortical network modulation and subcortical arousal maintenance, but its precise seizure-associated functions are not known. We recorded neuronal activity in three different thalamic regions and found divergent activity patterns, which may respectively participate in seizure propagation, impaired level of conscious arousal, and altered relay of information to the cortex during focal limbic seizures. These very different activity patterns within the thalamus may help explain why focal temporal lobe seizures often disrupt widespread network function, and can help guide future treatments aimed at restoring normal thalamocortical network activity and cognition. Copyright © 2017 the authors 0270-6474/17/3711441-14$15.00/0.

Seizures and Sleep in the Thalamus: Focal Limbic Seizures Show Divergent Activity Patterns in Different Thalamic Nuclei

PubMed Central

Feng, Li; Motelow, Joshua E.; Ma, Chanthia; Liu, Mengran; Zhan, Qiong; Jia, Ruonan; Xiao, Bo; Duque, Alvaro

2017-01-01

The thalamus plays diverse roles in cortical-subcortical brain activity patterns. Recent work suggests that focal temporal lobe seizures depress subcortical arousal systems and convert cortical activity into a pattern resembling slow-wave sleep. The potential simultaneous and paradoxical role of the thalamus in both limbic seizure propagation, and in sleep-like cortical rhythms has not been investigated. We recorded neuronal activity from the central lateral (CL), anterior (ANT), and ventral posteromedial (VPM) nuclei of the thalamus in an established female rat model of focal limbic seizures. We found that population firing of neurons in CL decreased during seizures while the cortex exhibited slow waves. In contrast, ANT showed a trend toward increased neuronal firing compatible with polyspike seizure discharges seen in the hippocampus. Meanwhile, VPM exhibited a remarkable increase in sleep spindles during focal seizures. Single-unit juxtacellular recordings from CL demonstrated reduced overall firing rates, but a switch in firing pattern from single spikes to burst firing during seizures. These findings suggest that different thalamic nuclei play very different roles in focal limbic seizures. While limbic nuclei, such as ANT, appear to participate directly in seizure propagation, arousal nuclei, such as CL, may contribute to depressed cortical function, whereas sleep spindles in relay nuclei, such as VPM, may interrupt thalamocortical information flow. These combined effects could be critical for controlling both seizure severity and impairment of consciousness. Further understanding of differential effects of seizures on different thalamocortical networks may lead to improved treatments directly targeting these modes of impaired function. SIGNIFICANCE STATEMENT Temporal lobe epilepsy has a major negative impact on quality of life. Previous work suggests that the thalamus plays a critical role in thalamocortical network modulation and subcortical arousal maintenance, but its precise seizure-associated functions are not known. We recorded neuronal activity in three different thalamic regions and found divergent activity patterns, which may respectively participate in seizure propagation, impaired level of conscious arousal, and altered relay of information to the cortex during focal limbic seizures. These very different activity patterns within the thalamus may help explain why focal temporal lobe seizures often disrupt widespread network function, and can help guide future treatments aimed at restoring normal thalamocortical network activity and cognition. PMID:29066556

Nuclear Safety Information Center, Its Products and Services

ERIC Educational Resources Information Center

Buchanan, J. R.

1970-01-01

The Nuclear Safety Information Center (NSIC) serves as a focal point for the collection, analysis and dissemination of information related to safety problems encountered in the design, analysis, and operation of nuclear facilities. (Author/AB)

78 FR 38067 - Agency Information Collection Activities: Submission for OMB Review; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-25

... (Amendment). Abstract: The National Fire Academy was established to advance the professional development of... Management Agency Institute serves as the national focal point for the development and delivery of emergency...

Robotic autopositioning of the operating microscope.

PubMed

Oppenlander, Mark E; Chowdhry, Shakeel A; Merkl, Brandon; Hattendorf, Guido M; Nakaji, Peter; Spetzler, Robert F

2014-06-01

Use of the operating microscope has become pervasive since its introduction to the neurosurgical world. Neuronavigation fused with the operating microscope has allowed accurate correlation of the focal point of the microscope and its location on the downloaded imaging study. However, the robotic ability of the Pentero microscope has not been utilized to orient the angle of the microscope or to change its focal length to hone in on a predefined target. To report a novel technology that allows automatic positioning of the operating microscope onto a set target and utilization of a planned trajectory, either determined with the StealthStation S7 by using preoperative imaging or intraoperatively with the microscope. By utilizing the current motorized capabilities of the Zeiss OPMI Pentero microscope, a robotic autopositioning feature was developed in collaboration with Surgical Technologies, Medtronic, Inc. (StealthStation S7). The system is currently being tested at the Barrow Neurological Institute. Three options were developed for automatically positioning the microscope: AutoLock Current Point, Align Parallel to Plan, and Point to Plan Target. These options allow the microscope to pivot around the lesion, hover in a set plane parallel to the determined trajectory, or rotate and point to a set target point, respectively. Integration of automatic microscope positioning into the operative workflow has potential to increase operative efficacy and safety. This technology is best suited for precise trajectories and entry points into deep-seated lesions.

Digital focusing of OCT images based on scalar diffraction theory and information entropy.

PubMed

Liu, Guozhong; Zhi, Zhongwei; Wang, Ruikang K

2012-11-01

This paper describes a digital method that is capable of automatically focusing optical coherence tomography (OCT) en face images without prior knowledge of the point spread function of the imaging system. The method utilizes a scalar diffraction model to simulate wave propagation from out-of-focus scatter to the focal plane, from which the propagation distance between the out-of-focus plane and the focal plane is determined automatically via an image-definition-evaluation criterion based on information entropy theory. By use of the proposed approach, we demonstrate that the lateral resolution close to that at the focal plane can be recovered from the imaging planes outside the depth of field region with minimal loss of resolution. Fresh onion tissues and mouse fat tissues are used in the experiments to show the performance of the proposed method.

A general purpose wideband optical spatial frequency spectrum analyzer

NASA Technical Reports Server (NTRS)

Ballard, G. S.; Mellor, F. A.

1972-01-01

The light scattered at various angles by a transparent media is studied. An example of these applications is the optical Fourier spectrum measurement resulting from various spatial frequencies which were recorded on a photographic emulsion. A method for obtaining these measurements consists of illuminating the test object with parallel monochromatic light. A stationary lens, placed in the resulting wavefield at a distance of one focal length from the object, will focus parallel waves emanating from the test object at a point lying in the focal plane of the lens. A light detector with a small filtering aperture is then used to measure the intensity variation of the light in the focal or transform plane of the lens. Such measurements require the use of a lens which is highly corrected for all of the common aberrations except chromatic aberration.

Kalman Filter for Calibrating a Telescope Focal Plane

NASA Technical Reports Server (NTRS)

Kang, Bryan; Bayard, David

2006-01-01

The instrument-pointing frame (IPF) Kalman filter, and an algorithm that implements this filter, have been devised for calibrating the focal plane of a telescope. As used here, calibration signifies, more specifically, a combination of measurements and calculations directed toward ensuring accuracy in aiming the telescope and determining the locations of objects imaged in various arrays of photodetectors in instruments located on the focal plane. The IPF Kalman filter was originally intended for application to a spaceborne infrared astronomical telescope, but can also be applied to other spaceborne and ground-based telescopes. In the traditional approach to calibration of a telescope, (1) one team of experts concentrates on estimating parameters (e.g., pointing alignments and gyroscope drifts) that are classified as being of primarily an engineering nature, (2) another team of experts concentrates on estimating calibration parameters (e.g., plate scales and optical distortions) that are classified as being primarily of a scientific nature, and (3) the two teams repeatedly exchange data in an iterative process in which each team refines its estimates with the help of the data provided by the other team. This iterative process is inefficient and uneconomical because it is time-consuming and entails the maintenance of two survey teams and the development of computer programs specific to the requirements of each team. Moreover, theoretical analysis reveals that the engineering/ science iterative approach is not optimal in that it does not yield the best estimates of focal-plane parameters and, depending on the application, may not even enable convergence toward a set of estimates.

Linear summation of outputs in a balanced network model of motor cortex

PubMed Central

Capaday, Charles; van Vreeswijk, Carl

2015-01-01

Given the non-linearities of the neural circuitry's elements, we would expect cortical circuits to respond non-linearly when activated. Surprisingly, when two points in the motor cortex are activated simultaneously, the EMG responses are the linear sum of the responses evoked by each of the points activated separately. Additionally, the corticospinal transfer function is close to linear, implying that the synaptic interactions in motor cortex must be effectively linear. To account for this, here we develop a model of motor cortex composed of multiple interconnected points, each comprised of reciprocally connected excitatory and inhibitory neurons. We show how non-linearities in neuronal transfer functions are eschewed by strong synaptic interactions within each point. Consequently, the simultaneous activation of multiple points results in a linear summation of their respective outputs. We also consider the effects of reduction of inhibition at a cortical point when one or more surrounding points are active. The network response in this condition is linear over an approximately two- to three-fold decrease of inhibitory feedback strength. This result supports the idea that focal disinhibition allows linear coupling of motor cortical points to generate movement related muscle activation patterns; albeit with a limitation on gain control. The model also explains why neural activity does not spread as far out as the axonal connectivity allows, whilst also explaining why distant cortical points can be, nonetheless, functionally coupled by focal disinhibition. Finally, we discuss the advantages that linear interactions at the cortical level afford to motor command synthesis. PMID:26097452

Applicability of the single equivalent point dipole model to represent a spatially distributed bio-electrical source

NASA Technical Reports Server (NTRS)

Armoundas, A. A.; Feldman, A. B.; Sherman, D. A.; Cohen, R. J.

2001-01-01

Although the single equivalent point dipole model has been used to represent well-localised bio-electrical sources, in realistic situations the source is distributed. Consequently, position estimates of point dipoles determined by inverse algorithms suffer from systematic error due to the non-exact applicability of the inverse model. In realistic situations, this systematic error cannot be avoided, a limitation that is independent of the complexity of the torso model used. This study quantitatively investigates the intrinsic limitations in the assignment of a location to the equivalent dipole due to distributed electrical source. To simulate arrhythmic activity in the heart, a model of a wave of depolarisation spreading from a focal source over the surface of a spherical shell is used. The activity is represented by a sequence of concentric belt sources (obtained by slicing the shell with a sequence of parallel plane pairs), with constant dipole moment per unit length (circumferentially) directed parallel to the propagation direction. The distributed source is represented by N dipoles at equal arc lengths along the belt. The sum of the dipole potentials is calculated at predefined electrode locations. The inverse problem involves finding a single equivalent point dipole that best reproduces the electrode potentials due to the distributed source. The inverse problem is implemented by minimising the chi2 per degree of freedom. It is found that the trajectory traced by the equivalent dipole is sensitive to the location of the spherical shell relative to the fixed electrodes. It is shown that this trajectory does not coincide with the sequence of geometrical centres of the consecutive belt sources. For distributed sources within a bounded spherical medium, displaced from the sphere's centre by 40% of the sphere's radius, it is found that the error in the equivalent dipole location varies from 3 to 20% for sources with size between 5 and 50% of the sphere's radius. Finally, a method is devised to obtain the size of the distributed source during the cardiac cycle.

Apparent diffusion coefficient of vertebral haemangiomas allows differentiation from malignant focal deposits in whole-body diffusion-weighted MRI.

PubMed

Winfield, Jessica M; Poillucci, Gabriele; Blackledge, Matthew D; Collins, David J; Shah, Vallari; Tunariu, Nina; Kaiser, Martin F; Messiou, Christina

2018-04-01

The aim of this study was to identify apparent diffusion coefficient (ADC) values for typical haemangiomas in the spine and to compare them with active malignant focal deposits. This was a retrospective single-institution study. Whole-body magnetic resonance imaging (MRI) scans of 106 successive patients with active multiple myeloma, metastatic prostate or breast cancer were analysed. ADC values of typical vertebral haemangiomas and malignant focal deposits were recorded. The ADC of haemangiomas (72 ROIs, median ADC 1,085×10 -6 mm 2 s -1 , interquartile range 927-1,295×10 -6 mm 2 s -1 ) was significantly higher than the ADC of malignant focal deposits (97 ROIs, median ADC 682×10 -6 mm 2 s -1 , interquartile range 583-781×10 -6 mm 2 s -1 ) with a p-value < 10 -6 . Receiver operating characteristic (ROC) analysis produced an area under the curve of 0.93. An ADC threshold of 872×10 -6 mm 2 s -1 separated haemangiomas from malignant focal deposits with a sensitivity of 84.7 % and specificity of 91.8 %. ADC values of classical vertebral haemangiomas are significantly higher than malignant focal deposits. The high ADC of vertebral haemangiomas allows them to be distinguished visually and quantitatively from active sites of disease, which show restricted diffusion. • Whole-body diffusion-weighted MRI is becoming widely used in myeloma and bone metastases. • ADC values of vertebral haemangiomas are significantly higher than malignant focal deposits. • High ADCs of haemangiomas allows them to be distinguished from active disease.

Chromatic diversity: a new approach for characterizing spatiotemporal coupling of ultrashort pulses.

PubMed

Bahk, Seung-Whan; Dorrer, Christophe; Bromage, Jake

2018-04-02

Two-dimensional chromatic aberrations are characterized by a single-shot scheme based on a simultaneous measurement of chromatically diversified focal spots. The chromatic diversity is introduced by a 2-D grating with holographic defocus terms. The chromatic aberrations in the beam are either subtracted or added by the additional known chromatic aberrations in the grating, depending on the diffraction order. By analyzing the asymmetry in the size of diffracted focal spots, input beam chromatic aberrations can be deduced. Theoretical discussions and experimental results are presented.

Remote focusing for programmable multi-layer differential multiphoton microscopy

PubMed Central

Hoover, Erich E.; Young, Michael D.; Chandler, Eric V.; Luo, Anding; Field, Jeffrey J.; Sheetz, Kraig E.; Sylvester, Anne W.; Squier, Jeff A.

2010-01-01

We present the application of remote focusing to multiphoton laser scanning microscopy and utilize this technology to demonstrate simultaneous, programmable multi-layer imaging. Remote focusing is used to independently control the axial location of multiple focal planes that can be simultaneously imaged with single element detection. This facilitates volumetric multiphoton imaging in scattering specimens and can be practically scaled to a large number of focal planes. Further, it is demonstrated that the remote focusing control can be synchronized with the lateral scan directions, enabling imaging in orthogonal scan planes. PMID:21326641

Quantum Well and Quantum Dot Modeling for Advanced Infrared Detectors and Focal Plane Arrays

NASA Technical Reports Server (NTRS)

Ting, David; Gunapala, S. D.; Bandara, S. V.; Hill, C. J.

2006-01-01

This viewgraph presentation reviews the modeling of Quantum Well Infrared Detectors (QWIP) and Quantum Dot Infrared Detectors (QDIP) in the development of Focal Plane Arrays (FPA). The QWIP Detector being developed is a dual band detector. It is capable of running on two bands Long-Wave Infrared (LWIR) and Medium Wavelength Infrared (MWIR). The same large-format dual-band FPA technology can be applied to Quantum Dot Infrared Photodetector (QDIP) with no modification, once QDIP exceeds QWIP in single device performance. Details of the devices are reviewed.

Adaptive Optics Communications Performance Analysis

NASA Technical Reports Server (NTRS)

Srinivasan, M.; Vilnrotter, V.; Troy, M.; Wilson, K.

2004-01-01

The performance improvement obtained through the use of adaptive optics for deep-space communications in the presence of atmospheric turbulence is analyzed. Using simulated focal-plane signal-intensity distributions, uncoded pulse-position modulation (PPM) bit-error probabilities are calculated assuming the use of an adaptive focal-plane detector array as well as an adaptively sized single detector. It is demonstrated that current practical adaptive optics systems can yield performance gains over an uncompensated system ranging from approximately 1 dB to 6 dB depending upon the PPM order and background radiation level.

Chromatic diversity: a new approach for characterizing spatiotemporal coupling of ultrashort pulses

DOE PAGES

Bahk, Seung-Whan; Dorrer, Christophe; Bromage, Jake

2018-01-01

Two-dimensional chromatic aberrations are characterized by a single-shot scheme based on a simultaneous measurement of chromatically diversified focal spots. The chromatic diversity is introduced by a 2-D grating with holographic defocus terms. The chromatic aberrations in the beam are either subtracted or added by the additional known chromatic aberrations in the grating, depending on the diffraction order. By analyzing the asymmetry in the size of diffracted focal spots, input beam chromatic aberrations can be deduced. Theoretical discussions and experimental results are also presented.

Characterization of a long-focal-length polycapillary optic for high-energy x-rays

NASA Astrophysics Data System (ADS)

Cari, Padiyar; Suparmi, -; Padiyar, Sushil D.; Gibson, Walter M.; MacDonald, Carolyn A.; Alexander, Cheryl D.; Joy, Marshall K.; Russell, Christine H.; Chen, Zewu

2000-11-01

Polycapillary fibers and a prototype collector for high energy x rays with a 2 m focal length have been fabricated and characterized. Measurements of a prototype collector, performed in collimating mode, show that the optic has high transmission, good uniformity, and small exit divergence. The transmission as a function of energy was analyzed using an extended single fiber geometrical optic simulation and the result shows that the simulation fits the data fairly well. Scatter transmission and contrast enhancement were measured in focusing mode using a parallel beam input.

Investigation on dynamics of red blood cells through their behavior as biophotonic lenses.

PubMed

Memmolo, Pasquale; Merola, Francesco; Miccio, Lisa; Mugnano, Martina; Ferraro, Pietro

2016-12-01

The possibility to adopt biological matter as photonic optical elements can open scenarios in biophotonics research. Recently, it has been demonstrated that a red blood cell (RBC) can be seen as an optofluidic microlens by showing its imaging capability as well as its focal tunability. Moreover, correlation between an RBC’s morphology and its behavior as a refractive optical element has been established and its exploitation for biomedical diagnostic purposes has been foreseen. In fact, any deviation from the healthy RBC morphology can be seen as additional aberration in the optical wavefront passing through the cell. By this concept, accurate localization of focal spots of RBCs can become very useful in the blood disorders identification. We investigate the three-dimensional positioning of such focal spots over time for samples with two different osmolarity conditions, i.e., when they assume discocyte and spherical shapes, respectively. We also demonstrate that a temporal variation of an RBC’s focal points along the optical axis is correlated to the temporal fluctuations in the RBC’s thickness maps. Furthermore, we show a sort of synchronization of the whole erythrocytes ensemble.

Local activation time sampling density for atrial tachycardia contact mapping: how much is enough?

PubMed

Williams, Steven E; Harrison, James L; Chubb, Henry; Whitaker, John; Kiedrowicz, Radek; Rinaldi, Christopher A; Cooklin, Michael; Wright, Matthew; Niederer, Steven; O'Neill, Mark D

2018-02-01

Local activation time (LAT) mapping forms the cornerstone of atrial tachycardia diagnosis. Although anatomic and positional accuracy of electroanatomic mapping (EAM) systems have been validated, the effect of electrode sampling density on LAT map reconstruction is not known. Here, we study the effect of chamber geometry and activation complexity on optimal LAT sampling density using a combined in silico and in vivo approach. In vivo 21 atrial tachycardia maps were studied in three groups: (1) focal activation, (2) macro-re-entry, and (3) localized re-entry. In silico activation was simulated on a 4×4cm atrial monolayer, sampled randomly at 0.25-10 points/cm2 and used to re-interpolate LAT maps. Activation patterns were studied in the geometrically simple porcine right atrium (RA) and complex human left atrium (LA). Activation complexity was introduced into the porcine RA by incomplete inter-caval linear ablation. In all cases, optimal sampling density was defined as the highest density resulting in minimal further error reduction in the re-interpolated maps. Optimal sampling densities for LA tachycardias were 0.67 ± 0.17 points/cm2 (focal activation), 1.05 ± 0.32 points/cm2 (macro-re-entry) and 1.23 ± 0.26 points/cm2 (localized re-entry), P = 0.0031. Increasing activation complexity was associated with increased optimal sampling density both in silico (focal activation 1.09 ± 0.14 points/cm2; re-entry 1.44 ± 0.49 points/cm2; spiral-wave 1.50 ± 0.34 points/cm2, P < 0.0001) and in vivo (porcine RA pre-ablation 0.45 ± 0.13 vs. post-ablation 0.78 ± 0.17 points/cm2, P = 0.0008). Increasing chamber geometry was also associated with increased optimal sampling density (0.61 ± 0.22 points/cm2 vs. 1.0 ± 0.34 points/cm2, P = 0.0015). Optimal sampling densities can be identified to maximize diagnostic yield of LAT maps. Greater sampling density is required to correctly reveal complex activation and represent activation across complex geometries. Overall, the optimal sampling density for LAT map interpolation defined in this study was ∼1.0-1.5 points/cm2. Published on behalf of the European Society of Cardiology

Observation of broadband terahertz wave generation from liquid water

NASA Astrophysics Data System (ADS)

Jin, Qi; E, Yiwen; Williams, Kaia; Dai, Jianming; Zhang, X.-C.

2017-08-01

Bulk liquid water is a strong absorber in the terahertz (THz) frequency range, due to which liquid water has historically been sworn off as a source for THz radiation. Here, we experimentally demonstrate the generation of broadband THz waves from liquid water excited by femtosecond laser pulses. Our measurements reveal the critical dependence of the THz field upon the relative position between the water film and the focal point of the laser beam. The THz radiation from liquid water shows distinct characteristics when compared with the THz radiation from air plasmas with single color optical excitation. First, the THz field is maximized with the laser beam of longer pulse durations. In addition, the p-polarized component of the emitted THz waves will be influenced by the polarization of the optical excitation beam. It is also shown that the energy of the THz radiation is linearly dependent on the excitation pulse energy.

A compact spectrum splitting concentrator for high concentration photovoltaics based on the dispersion of a lens

NASA Astrophysics Data System (ADS)

He, J.; Flowers, C. A.; Yao, Y.; Atwater, H. A.; Rockett, A. A.; Nuzzo, R. G.

2018-06-01

Photovoltaic devices used in conjunction with functional optical elements for light concentration and spectrum splitting are known to be a viable approach for highly efficient photovoltaics. Conventional designs employ discrete optical elements, each with the task of either performing optical concentration or separating the solar spectrum. In the present work, we examine the performance of a compact photovoltaic architecture in which a single lens plays a dual role as both a concentrator and a spectrum splitter, the latter made possible by exploiting its intrinsic dispersion. A four-terminal two-junction InGaP/GaAs device is prepared to validate the concept and illustrates pathways for improvements. A spectral separation in the visible range is demonstrated at the focal point of a plano-convex lens with a geometric concentration ratio of 1104X with respect to the InGaP subcell.

Experimental simulation of latent heat thermal energy storage and heat pipe thermal transport for dish concentrator solar receiver

NASA Technical Reports Server (NTRS)

Narayanan, R.; Zimmerman, W. F.; Poon, P. T. Y.

1981-01-01

Test results on a modular simulation of the thermal transport and heat storage characteristics of a heat pipe solar receiver (HPSR) with thermal energy storage (TES) are presented. The HPSR features a 15-25 kWe Stirling engine power conversion system at the focal point of a parabolic dish concentrator operating at 827 C. The system collects and retrieves solar heat with sodium pipes and stores the heat in NaF-MgF2 latent heat storage material. The trials were run with a single full scale heat pipe, three full scale TES containers, and an air-cooled heat extraction coil to replace the Stirling engine heat exchanger. Charging and discharging, constant temperature operation, mixed mode operation, thermal inertial, etc. were studied. The heat pipe performance was verified, as were the thermal energy storage and discharge rates and isothermal discharges.

[Prognostic value of EEG in acute posttraumatic coma (author's transl)].

PubMed

Walser, H; Friedli, W; Glinz, W

1981-12-01

To evaluate the prognostic power of a single EEG-record, the recordings of 50 patients with posttraumatic coma performed within 48 hours after the injury were compared with the outcome after 6 months. A 5-point scale comprising 2 EEG-patterns being notorious for their dismal prognostic significance (suppression bursts, alpha-coma) and changes of vigilance were used as a mean of visual assessment of the recordings. In 24 out of the 28 patients with a bad outcome, the EEG had shown the patterns of category I, II and III (suppression bursts, alpha coma, no changes of vigilance). Of the 22 patients with a good outcome, the EEG had been classified as IV or V (clearly discernible changes of vigilance, sleep patterns). Further findings of particular dismal prognostic significance were focal epileptic discharges, as 9 out of the 11 patients with this EEG pattern had not survived the posttraumatic coma for more than 6 months.

A liquid thermal gradient refractive index lens and using it to trap single living cell in flowing environments.

PubMed

Liu, H L; Shi, Y; Liang, L; Li, L; Guo, S S; Yin, L; Yang, Y

2017-03-29

A gradient refractive index (GRIN) lens has a great potential for on-chip imaging and detection systems because of its flat surface with reduced defects. This paper reports a liquid thermal GRIN lens prepared using heat conduction between only one liquid, and uses it as a tunable optical tweezer for single living cell trapping in a flowing environment. This liquid GRIN lens consists of a trapezoidal region in the upper layer which is used to establish a GRIN profile by the heat conduction between three streams of benzyl alcohol with different temperatures, and subsequently a rhombus region in the lower layer with compensation liquids to form a steady square-law parabolic refractive index profile only in transverse direction. Simulations and experiments successfully show the real-time tunability of the focusing properties. The focal length can be modulated in the range of 500 μm with the minimum focal length of 430 μm. A considerable high enhancement factor achieves 5.4 whereas the full width at half maximum is 4 μm. The response time of the GRIN lens is about 20 ms. Based on this enhancement, tunable optical trapping for single human embryonic kidney 293 cell in the range of 280 μm is demonstrated by varying the focal length and working distance which is difficult for solid optical tweezers. The considerable quality of this liquid GRIN lens indicates on-chip applications especially in high quality optical imaging, detection and cells' handling.

Reflective Properties of a Parabolic Mirror.

ERIC Educational Resources Information Center

Ramsey, Gordon P.

1991-01-01

An incident light ray parallel to the optical axis of a parabolic mirror will be reflected at the focal point and vice versa. Presents a mathematical proof that uses calculus, algebra, and geometry to prove this reflective property. (MDH)

Food for Thought.

ERIC Educational Resources Information Center

Knight, Ruth

1984-01-01

Discusses various ways in which snacks are used as the focal point of science lessons. They include writing a laboratory report after experimenting (and eating) lollipops and preparing peanut butter and jelly sandwiches following the exact directions supplied by students. (JN)

Integration of transportation for improved mobility.

DOT National Transportation Integrated Search

2017-07-04

Mobility management and improvement have become the focal point of the federal, state, and local transportation agencies over the last decade. Even with decreasing vehicle-miles-traveled (VMT) over the same time span, the congestion and delays have n...

Projection of distributed-collector solar-thermal electric power plant economics to years 1990-2000

NASA Technical Reports Server (NTRS)

Fujita, T.; Elgabalawi, N.; Herrera, G.; Turner, R. H.

1977-01-01

A preliminary comparative evaluation of distributed-collector solar thermal power plants was undertaken by projecting power plant economics of selected systems to the 1990 to 2000 time frame. The selected systems include: (1) fixed orientation collectors with concentrating reflectors and vacuum tube absorbers, (2) one axis tracking linear concentrator including parabolic trough and variable slat designs, and (3) two axis tracking parabolic dish systems including concepts with small heat engine-electric generator assemblies at each focal point as well as approaches having steam generators at the focal point with pipeline collection to a central power conversion unit. Comparisons are presented primarily in terms of energy cost and capital cost over a wide range of operating load factors. Sensitvity of energy costs for a range of efficiency and cost of major subsystems/components is presented to delineate critical technological development needs.

Development and Testing of a Power Trough System Using a Structurally-Efficient, High-Performance, Large-Aperture Concentrator with Thin Glass Reflector and Focal Point Rotation

DOE Office of Scientific and Technical Information (OSTI.GOV)

May, E. K.; Forristall, R.

2005-11-01

Industrial Solar Technology has assembled a team of experts to develop a large-aperture parabolic trough for the electric power market that moves beyond cost and operating limitations of 1980's designs based on sagged glass reflectors. IST's structurally efficient space frame design will require nearly 50% less material per square meter than a Solel LS-2 concentrator and the new trough will rotate around the focal point. This feature eliminates flexhoses that increase pump power, installation and maintenance costs. IST aims to deliver a concentrator module costing less than $100 per square meter that can produce temperatures up to 400 C. Themore » IST concentrator is ideally suited for application of front surface film reflectors and ensures that US corporations will manufacture major components, except for the high temperature receivers.« less

Cosmic Dawn Intensity Mapper (CDIM): Instrument and Mission Design

NASA Astrophysics Data System (ADS)

Unwin, Stephen C.; CDIM Team

2018-01-01

CDIM is the Cosmic Dawn Intensity Mapper, one of the probe-class missions currently under study for NASA. A detailed Report from the study will be submitted to NASA and for consideration by the Decadal Survey. The flight system will comprise a wide-field cryogenic telescope with a large focal plane array providing complete coverage from optical through mid-IR. The system will be deployed to L2 or Earth-trailing orbit, to provide a stable thermal environment and allow extended observations of fields selected to be cross-correlated with deep surveys in other wavebands. Spectra with will be measured for every point in each target field, using linear variable filters (LVFs). These filters eliminate the need for a spectrometer in the focal plane. Spectra are built up through simple imaging of a series of telescope pointings separated by small angular offsets. This poster presents the initial concept for the instrument and mission design.

A comparison between GO/aperture-field and physical-optics methods for offset reflectors

NASA Technical Reports Server (NTRS)

Rahmat-Samii, Y.

1984-01-01

Both geometrical optics (GO)/aperture-field and physical-optics (PO) methods are used extensively in the diffraction analysis of offset parabolic and dual reflectors. An analytical/numerical comparative study is performed to demonstrate the limitations of the GO/aperture-field method for accurately predicting the sidelobe and null positions and levels. In particular, it is shown that for offset parabolic reflectors and for feeds located at the focal point, the predicted far-field patterns (amplitude) by the GO/aperture-field method will always be symmetric even in the offset plane. This, of course, is inaccurate for the general case and it is shown that the physical-optics method can result in asymmetric patterns for cases in which the feed is located at the focal point. Representative numerical data are presented and a comparison is made with available measured data.

Laser-enhanced thermal effect of moderate intensity focused ultrasound on bio-tissues

NASA Astrophysics Data System (ADS)

Zhao, JinYu; Zhang, ShuYi; Shui, XiuJi; Fan, Li

2017-09-01

For avoiding extra-damage to healthy tissues surrounding the focal point during high intensity focused ultrasound (HIFU) treatment in medical therapy, to reduce the ultrasonic intensity outside the focal point is expected. Thus, the heating processes induced by moderate intensity focused ultrasound (MIFU) and enhanced by combined irradiation of laser pulses for bio-tissues are studied in details. For fresh bio-tissues, the enhanced thermal effects by pulsed laser combined with MIFU irradiation are observed experimentally. To explore the mechanisms of these effects, several tissue-mimicking materials composed of agar mixed with graphite powders are prepared and studied for comparison, but the laser-enhanced thermal effects in these mimicking materials are much less than that in the fresh bio-tissues. Therefore, it is suggested that the laser-enhanced thermal effects may be mainly attributed to bio-activities and related photo-bio-chemical effects of fresh tissues.

Micro spectrometer for parallel light and method of use

NASA Technical Reports Server (NTRS)

Park, Yeonjoon (Inventor); Choi, Sang H. (Inventor); King, Glen C. (Inventor); Elliott, James R. (Inventor)

2011-01-01

A spectrometer system includes an optical assembly for collimating light, a micro-ring grating assembly having a plurality of coaxially-aligned ring gratings, an aperture device defining an aperture circumscribing a target focal point, and a photon detector. An electro-optical layer of the grating assembly may be electrically connected to an energy supply to change the refractive index of the electro-optical layer. Alternately, the gratings may be electrically connected to the energy supply and energized, e.g., with alternating voltages, to change the refractive index. A data recorder may record the predetermined spectral characteristic. A method of detecting a spectral characteristic of a predetermined wavelength of source light includes generating collimated light using an optical assembly, directing the collimated light onto the micro-ring grating assembly, and selectively energizing the micro-ring grating assembly to diffract the predetermined wavelength onto the target focal point, and detecting the spectral characteristic using a photon detector.

D3D augmented reality imaging system: proof of concept in mammography.

PubMed

Douglas, David B; Petricoin, Emanuel F; Liotta, Lance; Wilson, Eugene

2016-01-01

The purpose of this article is to present images from simulated breast microcalcifications and assess the pattern of the microcalcifications with a technical development called "depth 3-dimensional (D3D) augmented reality". A computer, head display unit, joystick, D3D augmented reality software, and an in-house script of simulated data of breast microcalcifications in a ductal distribution were used. No patient data was used and no statistical analysis was performed. The D3D augmented reality system demonstrated stereoscopic depth perception by presenting a unique image to each eye, focal point convergence, head position tracking, 3D cursor, and joystick fly-through. The D3D augmented reality imaging system offers image viewing with depth perception and focal point convergence. The D3D augmented reality system should be tested to determine its utility in clinical practice.

Photogrammetry: An available surface characterization tool for solar concentrators. Part 2: Assessment of surfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shortis, M.; Johnston, G.

1997-11-01

In a previous paper, the results of photogrammetric measurements of a number of paraboloidal reflecting surfaces were presented. These results showed that photogrammetry can provide three-dimensional surface characterizations of such solar concentrators. The present paper describes the assessment of the quality of these surfaces as a derivation of the photogrammetrically produced surface coordinates. Statistical analysis of the z-coordinate distribution of errors indicates that these generally conform to a univariate Gaussian distribution, while the numerical assessment of the surface normal vectors on these surfaces indicates that the surface normal deviations appear to follow an approximately bivariate Gaussian distribution. Ray tracing ofmore » the measured surfaces to predict the expected flux distribution at the focal point of the 400 m{sup 2} dish show a close correlation with the videographically measured flux distribution at the focal point of the dish.« less

Method for pulse control in a laser including a stimulated brillouin scattering mirror system

DOEpatents

Dane, C. Brent; Hackel, Lloyd; Harris, Fritz B.

2007-10-23

A laser system, such as a master oscillator/power amplifier system, comprises a gain medium and a stimulated Brillouin scattering SBS mirror system. The SBS mirror system includes an in situ filtered SBS medium that comprises a compound having a small negative non-linear index of refraction, such as a perfluoro compound. An SBS relay telescope having a telescope focal point includes a baffle at the telescope focal point which blocks off angle beams. A beam splitter is placed between the SBS mirror system and the SBS relay telescope, directing a fraction of the beam to an alternate beam path for an alignment fiducial. The SBS mirror system has a collimated SBS cell and a focused SBS cell. An adjustable attenuator is placed between the collimated SBS cell and the focused SBS cell, by which pulse width of the reflected beam can be adjusted.

Stimulated Brillouin scattering mirror system, high power laser and laser peening method and system using same

DOEpatents

Dane, C Brent [Livermore, CA; Hackel, Lloyd [Livermore, CA; Harris, Fritz B [Rocklin, CA

2007-04-24

A laser system, such as a master oscillator/power amplifier system, comprises a gain medium and a stimulated Brillouin scattering SBS mirror system. The SBS mirror system includes an in situ filtered SBS medium that comprises a compound having a small negative non-linear index of refraction, such as a perfluoro compound. An SBS relay telescope having a telescope focal point includes a baffle at the telescope focal point which blocks off angle beams. A beam splitter is placed between the SBS mirror system and the SBS relay telescope, directing a fraction of the beam to an alternate beam path for an alignment fiducial. The SBS mirror system has a collimated SBS cell and a focused SBS cell. An adjustable attenuator is placed between the collimated SBS cell and the focused SBS cell, by which pulse width of the reflected beam can be adjusted.

Relay telescope including baffle, and high power laser amplifier utilizing the same

DOEpatents

Dane, C. Brent; Hackel, Lloyd; Harris, Fritz B.

2006-09-19

A laser system includes an optical path having an intracavity relay telescope with a telescope focal point for imaging an output of the gain medium between an image location at or near the gain medium and an image location at or near an output coupler for the laser system. A kinematic mount is provided within a vacuum chamber, and adapted to secure beam baffles near the telescope focal point. An access port on the vacuum chamber is adapted for allowing insertion and removal of the beam baffles. A first baffle formed using an alignment pinhole aperture is used during alignment of the laser system. A second tapered baffle replaces the alignment aperture during operation and acts as a far-field baffle in which off angle beams strike the baffle a grazing angle of incidence, reducing fluence levels at the impact areas.

Familial temporal lobe epilepsy due to focal cortical dysplasia type IIIa.

PubMed

Fabera, Petr; Krijtova, Hana; Tomasek, Martin; Krysl, David; Zamecnik, Josef; Mohapl, Milan; Jiruska, Premysl; Marusic, Petr

2015-09-01

Focal cortical dysplasia (FCD) represents a common cause of refractory epilepsy. It is considered a sporadic disorder, but its occasional familial occurrence suggests the involvement of genetic mechanisms. Siblings with intractable epilepsy were referred for epilepsy surgery evaluation. Both patients were examined using video-EEG monitoring, MRI examination and PET imaging. They underwent left anteromedial temporal lobe resection. Electroclinical features pointed to left temporal lobe epilepsy and MRI examination revealed typical signs of left-sided hippocampal sclerosis and increased white matter signal intensity in the left temporal pole. PET examination confirmed interictal hypometabolism in the left temporal lobe. Histopathological examination of resected tissue demonstrated the presence FCD type IIIa, i.e. hippocampal sclerosis and focal cortical dysplasia in the left temporal pole. We present a unique case of refractory mesial temporal lobe epilepsy in siblings, characterized by an identical clinical profile and histopathology of FCD type IIIa, who were successfully treated by epilepsy surgery. The presence of such a high concordance between the clinical and morphological data, together with the occurrence of epilepsy and febrile seizures in three generations of the family pedigree points towards a possible genetic nature of the observed FCD type IIIa. Copyright © 2015 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

Commander islands as the significant point for monitoring some dangerous changes in the Beringia ecosystem

Treesearch

Vladimir Sevostianov

2007-01-01

This paper explores the many natural, historical, and economic reasons the Commander Islands are an essential focal point for field expedition work and finally for conservation projects in the unique ecosystem of the North Pacific. Around the Commander Islands we can find a biologically productive and diverse marine environment. For example, it is one of the richest...

A Comparison of the Cognitive and Personal Development of College-Level Mathematics Students and Developmental Mathematics Students at a Community College

ERIC Educational Resources Information Center

Smith, Bridgett Pressley

2010-01-01

Education is a major focal point of individual justice within a free society as well as a central point of human capital for the world. This study compared the cognitive and personal developmental levels of community college students enrolled in developmental-level mathematics courses to students enrolled in college-level mathematics courses. In…

Paraxial ray solution for liquid-filled variable focus lenses

NASA Astrophysics Data System (ADS)

Wang, Lihui; Oku, Hiromasa; Ishikawa, Masatoshi

2017-12-01

We propose a general solution for determining the cardinal points and effective focal length of a liquid-filled variable focus lens to aid in understanding the dynamic behavior of the lens when the focal length is changed. A prototype of a variable focus lens was fabricated and used to validate the solution. A simplified solution was also presented that can be used to quickly and conveniently calculate the performance of the lens. We expect that the proposed solutions will improve the design of optical systems that contain variable focus lenses, such as machine vision systems with zoom and focus functions.

Absolute OH Number Density Measurements in Lean Fuel-Air Mixtures Excited by a Repetitively Pulsed Nanosecond Discharge

DTIC Science & Technology

2013-01-01

cross section quartz channel with wall thickness of 1.75 mm. Two plane quartz windows are fused to the ends of the channel at Brewster angle (for ~308...ttp :// ar c. ai aa .o rg | D O I: 1 0. 25 14 /6 .2 01 3- 43 2 4 about 1 J/pulse, softly focused over the flame using a lens with a focal...region with an f=550 mm lens . The LIF signal sampling volume was about 100 mm away from the laser focal point, to avoid transition saturation. The

High intensity focused ultrasound (HIFU) focal spot localization using harmonic motion imaging (HMI).

PubMed

Han, Yang; Hou, Gary Yi; Wang, Shutao; Konofagou, Elisa

2015-08-07

Several ultrasound-based imaging modalities have been proposed for image guidance and monitoring of high-intensity focused ultrasound (HIFU) treatment. However, accurate localization and characterization of the effective region of treatment (focal spot) remain important obstacles in the clinical implementation of HIFU ablation. Harmonic motion imaging for focused ultrasound (HMIFU) is a HIFU monitoring technique that utilizes radiation-force-induced localized oscillatory displacement. HMIFU has been shown to correctly identify the formation and extent of HIFU thermal ablation lesions. However a significant problem remains in identifying the location of the HIFU focus, which is necessary for treatment planning. In this study, the induced displacement was employed to localize the HIFU focal spot inside the tissue prior to treatment. Feasibility was shown with two separate systems. The 1D HMIFU system consisted of a HIFU transducer emitting an amplitude-modulated HIFU beam for mechanical excitation and a confocal single-element, pulse-echo transducer for simultaneous RF acquisition. The 2D HIFU system consists of a HIFU phased array, and a co-axial imaging phased array for simultaneous imaging. Initial feasibility was first performed on tissue-mimicking gelatin phantoms and the focal zone was defined as the region corresponding to the -3dB full width at half maximum of the HMI displacement. Using the same parameters, in vitro experiments were performed in canine liver specimens to compare the defined focal zone with the lesion. In vitro measurements showed good agreement between the HMI predicted focal zone and the induced HIFU lesion location. HMIFU was experimentally shown to be capable of predicting and tracking the focal region in both phantoms and in vitro tissues. The accuracy of focal spot localization was evaluated by comparing with the lesion location in post-ablative tissues, with a R(2) = 0.821 at p < 0.002 in the 2D HMI system. We demonstrated the feasibility of using this HMI-based technique to localize the HIFU focal spot without inducing thermal changes during the planning phase. The focal spot localization method has also been applied on ex vivo human breast tissue ablation and can be fully integrated into any HMI system for planning purposes.

High Intensity Focused Ultrasound (HIFU) Focal Spot Localization Using Harmonic Motion Imaging (HMI)

PubMed Central

Han, Yang; Hou, Gary Yi; Wang, Shutao; Konofagou, Elisa

2015-01-01

Several ultrasound-based imaging modalities have been proposed for image guidance and monitoring of High-Intensity Focused Ultrasound (HIFU) treatment. However, accurate localization and characterization of the effective region of treatment (focal spot) remain important obstacles in the clinical implementation of HIFU ablation. Harmonic Motion Imaging for Focused Ultrasound (HMIFU) is a HIFU monitoring technique that utilizes radiation-force-induced localized oscillatory displacement. HMIFU has been shown to correctly identify the formation and extent of HIFU thermal ablation lesions. However a significant problem remains in identifying the location of the HIFU focus, which is necessary for treatment planning. In this study, the induced displacement was employed to localize the HIFU focal spot inside the tissue prior to treatment. Feasibility was shown with two separate systems. The 1D HMIFU system consisted of a HIFU transducer emitting an amplitude-modulated HIFU beam for mechanical excitation and a confocal single-element, pulse-echo transducer for simultaneous RF acquisition. The 2D HIFU system consists of a HIFU phased array, and a co-axial imaging phased array for simultaneous imaging. Initial feasibility was first performed on tissue-mimicking gelatin phantoms and the focal zone was defined as the region corresponding to the −3 dB full width at half maximum of the HMI displacement. Using the same parameters, in vitro experiments were performed in canine liver specimens to compare the defined focal zone with the lesion. In vitro measurements showed good agreement between the HMI predicted focal zone and the induced HIFU lesion location. HMIFU was experimentally shown to be capable of predicting and tracking the focal region in both phantoms and in vitro tissues. The accuracy of focal spot localization was evaluated by comparing with the lesion location in post-ablative tissues, with a R2 = 0.821 at p<0.002 in the 2D HMI system. We demonstrated the feasibility of using this HMI-based technique to localize the HIFU focal spot without inducing thermal changes during the planning phase. The focal spot localization method has also been applied on ex vivo human breast tissue ablation and can be fully integrated into any HMI system for planning purposes. PMID:26184846

High intensity focused ultrasound (HIFU) focal spot localization using harmonic motion imaging (HMI)

NASA Astrophysics Data System (ADS)

Han, Yang; Hou, Gary Yi; Wang, Shutao; Konofagou, Elisa

2015-08-01

Several ultrasound-based imaging modalities have been proposed for image guidance and monitoring of high-intensity focused ultrasound (HIFU) treatment. However, accurate localization and characterization of the effective region of treatment (focal spot) remain important obstacles in the clinical implementation of HIFU ablation. Harmonic motion imaging for focused ultrasound (HMIFU) is a HIFU monitoring technique that utilizes radiation-force-induced localized oscillatory displacement. HMIFU has been shown to correctly identify the formation and extent of HIFU thermal ablation lesions. However a significant problem remains in identifying the location of the HIFU focus, which is necessary for treatment planning. In this study, the induced displacement was employed to localize the HIFU focal spot inside the tissue prior to treatment. Feasibility was shown with two separate systems. The 1D HMIFU system consisted of a HIFU transducer emitting an amplitude-modulated HIFU beam for mechanical excitation and a confocal single-element, pulse-echo transducer for simultaneous RF acquisition. The 2D HIFU system consists of a HIFU phased array, and a co-axial imaging phased array for simultaneous imaging. Initial feasibility was first performed on tissue-mimicking gelatin phantoms and the focal zone was defined as the region corresponding to the  -3dB full width at half maximum of the HMI displacement. Using the same parameters, in vitro experiments were performed in canine liver specimens to compare the defined focal zone with the lesion. In vitro measurements showed good agreement between the HMI predicted focal zone and the induced HIFU lesion location. HMIFU was experimentally shown to be capable of predicting and tracking the focal region in both phantoms and in vitro tissues. The accuracy of focal spot localization was evaluated by comparing with the lesion location in post-ablative tissues, with a R2 = 0.821 at p  <  0.002 in the 2D HMI system. We demonstrated the feasibility of using this HMI-based technique to localize the HIFU focal spot without inducing thermal changes during the planning phase. The focal spot localization method has also been applied on ex vivo human breast tissue ablation and can be fully integrated into any HMI system for planning purposes.

The principle of a three-staged operation in the surgery of acne scars.

PubMed

Whang, K K; Lee, M

1999-01-01

Acne scars cannot be effectively corrected by a single treatment modality because of their widely varied depth and width. We assessed the effectiveness of staged combinations of several surgical modalities in the treatment of acne scars. Focal chemical peeling, carbon dioxide (CO2) laser, scar excision, punch grafting, and dermabrasion were used. Initially, focal chemical peeling was performed on all patients and then CO2 laser, scar excision, and punch grafts were used for deep scars. Finally, dermabrasion was done for the remaining scars. Seventy-five percent of patients showed excellent or good results. The degree of improvement increased as the follow-up periods and number of focal chemical peeling procedures increased and as the 3-staged operation progressed. A 3-staged operation is effective in the treatment of patients with various types of acne scars.

A Demonstration of a Versatile Low-order Wavefront Sensor Tested on Multiple Coronographs

NASA Astrophysics Data System (ADS)

Singh, Garima; Lozi, Julien; Jovanovic, Nemanja; Guyon, Olivier; Baudoz, Pierre; Martinache, Frantz; Kudo, Tomoyuki

2017-09-01

Detecting faint companions in close proximity to stars is one of the major goals of current/planned ground- and space-based high-contrast imaging instruments. High-performance coronagraphs can suppress the diffraction features and gain access to companions at small angular separation. However, the uncontrolled pointing errors degrade the coronagraphic performance by leaking starlight around the coronagraphic focal-plane mask, preventing the detection of companions at small separations. A Lyot-stop low-order wavefront sensor (LLOWFS) was therefore introduced to calibrate and measure these aberrations for focal-plane phase mask coronagraphs. This sensor quantifies the variations in wavefront error decomposed into a few Zernike modes by reimaging the diffracted starlight rejected by a reflective Lyot stop. The technique was tested with several coronagraphs on the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system at the Subaru Telescope. The wavefront was decomposed into 15 and 35 Zernike modes with an occulting and focal-plane phase mask coronagraph, respectively, which were used to drive a closed-loop correction in the laboratory. Using a 2000-actuator deformable mirror, a closed-loop pointing stability between 10-3-10-4 λ/D was achieved in the laboratory in H-band, with sub nanometer residuals for the other Zernike modes (Noll index > 4). On-sky, the low-order control of 10+ Zernike modes for the phase-induced amplitude apodization and the vector vortex coronagraphs was demonstrated, with a closed-loop pointing stability of {10}-4λ /D under good seeing and {10}-3λ /D under moderate seeing conditions readily achievable.

Imaging patterns and focal lesions in fatty liver: a pictorial review.

PubMed

Venkatesh, Sudhakar K; Hennedige, Tiffany; Johnson, Geoffrey B; Hough, David M; Fletcher, Joel G

2017-05-01

Non-alcoholic fatty liver disease is the most common cause of chronic liver disease and affects nearly one-third of US population. With the increasing trend of obesity in the population, associated fatty change in the liver will be a common feature observed in imaging studies. Fatty liver causes changes in liver parenchyma appearance on imaging modalities including ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) and may affect the imaging characteristics of focal liver lesions (FLLs). The imaging characteristics of FLLs were classically described in a non-fatty liver. In addition, focal fatty change and focal fat sparing may also simulate FLLs. Knowledge of characteristic patterns of fatty change in the liver (diffuse, geographical, focal, subcapsular, and perivascular) and their impact on the detection and characterization of FLL is therefore important. In general, fatty change may improve detection of FLLs on MRI using fat suppression sequences, but may reduce sensitivity on a single-phase (portal venous) CT and conventional ultrasound. In patients with fatty liver, MRI is generally superior to ultrasound and CT for detection and characterization of FLL. In this pictorial essay, we describe the imaging patterns of fatty change in the liver and its effect on detection and characterization of FLLs on ultrasound, CT, MRI, and PET.

High-intensity interstitial ultrasound for thermal ablation of focal cancer targets in prostate

NASA Astrophysics Data System (ADS)

Salgaonkar, Vasant A.; Scott, Serena; Kurhanewicz, John; Diederich, Chris J.

2017-03-01

Recent advances in image based techniques such as multi-parametric MRI (MP-MRI) can provide precise targeting of focal disease in the prostate. Thermal ablation of such cancer targets while avoiding rectum, urethra, neurovascular bundles (NVB) and sphincter is clinically challenging. The approach described here employs multi-element ultrasound linear arrays designed for transperineal placement within prostate. They consist of independently powered sectored tubular transducers (6.5 - 8.0 MHz) that provide spatial control of energy deposition in angle and length. Volumetric ablation strategies were investigated through patient-specific biothermal models based on Pennes bioheat transfer equation. The acoustic and heat transfer models used here have been validated in several previous simulation and experimental studies. Focal disease sites in prostate were identified through multi-parametric MR images of representative patient cases (n=3). Focal cancer lesions and critical anatomy (prostate, urethra, rectum, bladder, seminal vesicles) were manually segmented (Mimics, Materialise) and converted to 3D finite element meshes (3-Matic, Materialise). The chosen test cases consisted of patients with medium and large sized glands and models of bulk tissue ablation covered volumes in a single quadrant in posterior prostate, hemi-gland targets and "hockey-stick" targets (lesions in three quadrants). Ultrasound applicator placement was determined such that devices were positioned along the prostate periphery while avoiding surrounding anatomy. Transducer sector angles were chosen based on applicator location within limits of fabrication practicability. Thermal models were numerically solved using finite element methods (FEM) in COMSOL Multiphysics. Temperature and thermal dose distributions were calculated to determine treated volumes (> 240 CEM43C, >52 °C) and safety profiles (<10 CEM43C, <45 °C) for nerve, rectal and urethral sparing. Modeling studies indicated that focal targets could be ablated with single or multiple interstitial applicators placed along the prostate periphery. In the representative cases explored during this study, thermal targets could be ablated with acoustic intensity values between 11 - 19 W/cm2 within 6 - 15 min of sonication time. Unifocal ablation could be performed by a single directional applicator (210° sectors). Hemi-gland targets were ablated by two directional applicators (210° sectors). Hockey-stick ablations were performed using 3 directional applicators (2 - 210° and 1 - 150°).

TES FAQ

Atmospheric Science Data Center

2013-03-14

... General Information When did TES begin taking measurements? TES began making measurements on August 22, ... contains data from a single TES orbit for one focal plane. Note that a TES orbit starts at the South Pole Apex. A Level 1B ...

Math and Humane Education.

ERIC Educational Resources Information Center

DeRosa, Bill

1986-01-01

Describes an activity designed to improve students' skills at solving mathematical word problems through an awareness of the pet overpopulation problem. Uses the concept of cumulative female offspring as a focal point in assisting students to analyze and work through word problems. (ML)

Utilizing Proverbs as a Focal Point to Cultural Awareness and Communicative Competence: Illustrations from Africa.

ERIC Educational Resources Information Center

Richmond, Edmun B.

1987-01-01

Proposes a model of target- and native-language proverb comparison which can be used to assist proverb analysis in the language curriculum, using examples from Mandinka, a West African language. (Author/CB)

Revision to the SUDAS traffic signal standards : phase 2.

DOT National Transportation Integrated Search

2012-05-01

This report provides a summary of the updates to the traffic signal content within the Iowa Statewide Urban Design and Specifications : (SUDAS) Design Manual Chapter 13 and Standard Specifications Division 8. Major focal points included pole footing ...

Digital focusing of OCT images based on scalar diffraction theory and information entropy

PubMed Central

Liu, Guozhong; Zhi, Zhongwei; Wang, Ruikang K.

2012-01-01

This paper describes a digital method that is capable of automatically focusing optical coherence tomography (OCT) en face images without prior knowledge of the point spread function of the imaging system. The method utilizes a scalar diffraction model to simulate wave propagation from out-of-focus scatter to the focal plane, from which the propagation distance between the out-of-focus plane and the focal plane is determined automatically via an image-definition-evaluation criterion based on information entropy theory. By use of the proposed approach, we demonstrate that the lateral resolution close to that at the focal plane can be recovered from the imaging planes outside the depth of field region with minimal loss of resolution. Fresh onion tissues and mouse fat tissues are used in the experiments to show the performance of the proposed method. PMID:23162717

An Atomic Lens Using a Focusing Hollow Beam

NASA Astrophysics Data System (ADS)

Xia, Yong; Yin, Jian-Ping; Wang, Yu-Zhu

2003-05-01

We propose a new method to generate a focused hollow laser beam by using an azimuthally distributed 2pi-phase plate and a convergent thin lens, and calculate the intensity distribution of the focused hollow beam in free propagation space. The relationship between the waist wo of the incident collimated Gaussian beam and the dark spot size of the focused hollow beam at the focal point, and the relationship between the focal length f of the thin lens and the dark spot size are studied respectively. The optical potential of the blue-detuned focused hollow beam for 85Rb atoms is calculated. Our study shows that when the larger waist w of the incident Gaussian beam and the shorter focal length f of the lens are chosen, we can obtain an extremely small dark spot size of the focused hollow beam, which can be used to form an atomic lens with a resolution of several angstroms.

Accurate acoustic power measurement for low-intensity focused ultrasound using focal axial vibration velocity

NASA Astrophysics Data System (ADS)

Tao, Chenyang; Guo, Gepu; Ma, Qingyu; Tu, Juan; Zhang, Dong; Hu, Jimin

2017-07-01

Low-intensity focused ultrasound is a form of therapy that can have reversible acoustothermal effects on biological tissue, depending on the exposure parameters. The acoustic power (AP) should be chosen with caution for the sake of safety. To recover the energy of counteracted radial vibrations at the focal point, an accurate AP measurement method using the focal axial vibration velocity (FAVV) is proposed in explicit formulae and is demonstrated experimentally using a laser vibrometer. The experimental APs for two transducers agree well with theoretical calculations and numerical simulations, showing that AP is proportional to the square of the FAVV, with a fixed power gain determined by the physical parameters of the transducers. The favorable results suggest that the FAVV can be used as a valuable parameter for non-contact AP measurement, providing a new strategy for accurate power control for low-intensity focused ultrasound in biomedical engineering.

Generation of a sub-half-wavelength focal spot with purely transverse spin angular momentum

NASA Astrophysics Data System (ADS)

Hang, Li; Fu, Jian; Yu, Xiaochang; Wang, Ying; Chen, Peifeng

2017-11-01

We theoretically demonstrate that optical focus fields with purely transverse spin angular momentum (SAM) can be obtained when a kind of special incident fields is focused by a high numerical aperture (NA) aplanatic lens (AL). When the incident pupil fields are refracted by an AL, two transverse Cartesian components of the electric fields at the exit pupil plane do not have the same order of sinusoidal or cosinoidal components, resulting in zero longitudinal SAMs of the focal fields. An incident field satisfying above conditions is then proposed. Using the Richard-Wolf vectorial diffraction theory, the energy density and SAM density distributions of the tightly focused beam are calculated and the results clearly validate the proposed theory. In addition, a sub-half-wavelength focal spot with purely transverse SAM can be achieved and a flattop energy density distribution parallel to z-axis can be observed around the maximum energy density point.

Superlattice Barrier Infrared Detector Development at the Jet Propulsion Laboratory

NASA Technical Reports Server (NTRS)

Ting, David Z.; Soibel, Alexander; Rafol, Sir B.; Nguyen, Jean; Hoglund, Linda; Khoshakhlagh, Arezou; Keo, Sam A.; Liu, John K.; Mumolo, Jason M.

2011-01-01

We report recent efforts in achieving state-of-the-art performance in type-II superlattice based infrared photodetectors using the barrier infrared detector architecture. We used photoluminescence measurements for evaluating detector material and studied the influence of the material quality on the intensity of the photoluminescence. We performed direct noise measurements of the superlattice detectors and demonstrated that while intrinsic 1/f noise is absent in superlattice heterodiode, side-wall leakage current can become a source of strong frequency-dependent noise. We developed an effective dry etching process for these complex antimonide-based superlattices that enabled us to fabricate single pixel devices as well as large format focal plane arrays. We describe the demonstration of a 1024x1024 pixel long-wavelength infrared focal plane array based the complementary barrier infrared detector (CBIRD) design. An 11.5 micron cutoff focal plane without anti-reflection coating has yielded noise equivalent differential temperature of 53 mK at operating temperature of 80 K, with 300 K background and cold-stop. Imaging results from a recent 10 ?m cutoff focal plane array are also presented.

High Frequency High Spectral Resolution Focal Plane Arrays for AtLAST

NASA Astrophysics Data System (ADS)

Baryshev, Andrey

2018-01-01

Large collecting area single dish telescope such as ATLAST will be especially effective for medium (R 1000) and high (R 50000) spectral resolution observations. Large focal plane array is a natural solution to increase mapping speed. For medium resolution direct detectors with filter banks (KIDs) and or heterodyne technology can be employed. We will analyze performance limits of comparable KID and SIS focal plane array taking into account quantum limit and high background condition of terrestrial observing site. For large heterodyne focal plane arrays, a high current density AlN junctions open possibility of large instantaneous bandwidth >40%. This and possible multi frequency band FPSs presents a practical challenge for spatial sampling and scanning strategies. We will discuss phase array feeds as a possible solution, including a modular back-end system, which can be shared between KID and SIS based FPA. Finally we will discuss achievable sensitivities and pixel co unts for a high frequency (>500 GHz) FPAs and address main technical challenges: LO distribution, wire counts, bias line multiplexing, and monolithic vs. discrete mixer component integration.

Rapid computation of the amplitude and phase of tightly focused optical fields distorted by scattering particles

PubMed Central

Ranasinghesagara, Janaka C.; Hayakawa, Carole K.; Davis, Mitchell A.; Dunn, Andrew K.; Potma, Eric O.; Venugopalan, Vasan

2014-01-01

We develop an efficient method for accurately calculating the electric field of tightly focused laser beams in the presence of specific configurations of microscopic scatterers. This Huygens–Fresnel wave-based electric field superposition (HF-WEFS) method computes the amplitude and phase of the scattered electric field in excellent agreement with finite difference time-domain (FDTD) solutions of Maxwell’s equations. Our HF-WEFS implementation is 2–4 orders of magnitude faster than the FDTD method and enables systematic investigations of the effects of scatterer size and configuration on the focal field. We demonstrate the power of the new HF-WEFS approach by mapping several metrics of focal field distortion as a function of scatterer position. This analysis shows that the maximum focal field distortion occurs for single scatterers placed below the focal plane with an offset from the optical axis. The HF-WEFS method represents an important first step toward the development of a computational model of laser-scanning microscopy of thick cellular/tissue specimens. PMID:25121440

Structured Laguerre-Gaussian beams for mitigation of spherical aberration in tightly focused regimes

NASA Astrophysics Data System (ADS)

Haddadi, S.; Bouzid, O.; Fromager, M.; Hasnaoui, A.; Harfouche, A.; Cagniot, E.; Forbes, A.; Aït-Ameur, K.

2018-04-01

Many laser applications utilise a focused laser beam having a single-lobed intensity profile in the focal plane, ideally with the highest possible on-axis intensity. Conventionally, this is achieved with the lowest-order Laguerre-Gaussian mode (LG00), the Gaussian beam, in a tight focusing configuration. However, tight focusing often involves significant spherical aberration due to the high numerical aperture of the systems involved, thus degrading the focal quality. Here, we demonstrate that a high-order radial LG p0 mode can be tailored to meet and in some instances exceed the performance of the Gaussian. We achieve this by phase rectification of the mode using a simple binary diffractive optic. By way of example, we show that the focusing of a rectified LG50 beam is almost insensitive to a spherical aberration coefficient of over three wavelengths, in contrast with the usual Gaussian beam for which the intensity of the focal spot is reduced by a factor of two. This work paves the way towards enhanced focal spots using structured light.

Glycogen Synthase Kinase 3β Dictates Podocyte Motility and Focal Adhesion Turnover by Modulating Paxillin Activity

PubMed Central

Xu, Weiwei; Ge, Yan; Liu, Zhihong; Gong, Rujun

2015-01-01

Aberrant focal adhesion turnover is centrally involved in podocyte actin cytoskeleton disorganization and foot process effacement. The structural and dynamic integrity of focal adhesions is orchestrated by multiple cell signaling molecules, including glycogen synthase kinase 3β (GSK3β), a multitasking kinase lately identified as a mediator of kidney injury. However, the role of GSK3β in podocytopathy remains obscure. In doxorubicin (Adriamycin)-injured podocytes, lithium, a GSK3β inhibitor and neuroprotective mood stabilizer, obliterated the accelerated focal adhesion turnover, rectified podocyte hypermotility, and restored actin cytoskeleton integrity. Mechanistically, lithium counteracted the doxorubicin-elicited GSK3β overactivity and the hyperphosphorylation and overactivation of paxillin, a focal adhesion–associated adaptor protein. Moreover, forced expression of a dominant negative kinase dead mutant of GSK3β highly mimicked, whereas ectopic expression of a constitutively active GSK3β mutant abolished, the effect of lithium in doxorubicin-injured podocytes, suggesting that the effect of lithium is mediated, at least in part, through inhibition of GSK3β. Furthermore, paxillin interacted with GSK3β and served as its substrate. In mice with doxorubicin nephropathy, a single low dose of lithium ameliorated proteinuria and glomerulosclerosis. Consistently, lithium therapy abrogated GSK3β overactivity, blunted paxillin hyperphosphorylation, and reinstated actin cytoskeleton integrity in glomeruli associated with an early attenuation of podocyte foot process effacement. Thus, GSK3β-modulated focal adhesion dynamics might serve as a novel therapeutic target for podocytopathy. PMID:25239564

Clinical and Demographic Characteristics Related to Onset

PubMed Central

Norris, Scott A; Jinnah, H A; Espay, Alberto J.; Klein, Christine; Brüggemann, Norbert; Barbano, Richard L.; Malaty, Irene; Rodriguez, Ramon L.; Vidailhet, Marie; Roze, Emmanuel; Reich, Stephen G.; Berman, Brian D.; LeDoux, Mark S.; Richardson, Sarah Pirio; Agarwal, Pinky; Mari, Zoltan; Ondo, William; Shih, Ludy C; Fox, Susan; Berardelli, Alfredo; Testa, Claudia M; Chang, Florence CF; Troung, Daniel; Nahab, Fatta; Xie, Tao; Hallett, Mark; Rosen, Ami R; Wright, Laura J; Perlmutter, JS

2016-01-01

Background Clinical characteristics of isolated, idiopathic cervical dystonia such as onset site and spread to and from additional body regions have been addressed in single-site studies with limited data and incomplete or variable dissociation of focal and segmental subtypes. Objectives To characterize clinical characteristics and demographics of isolated, idiopathic cervical dystonia in the largest standardized, multicenter cohort. Methods The Dystonia Coalition, through a consortium of 37 recruiting sites in North America, Europe and Australia recruited 1477 participants with focal (60.7%) or segmental (39.3%) cervical dystonia on examination. Clinical and demographic characteristics were evaluated in terms of the body region of dystonia onset and spread. Results Site of dystonia onset was: a) focal neck only (78.5%), b) focal onset elsewhere with later segmental spread to neck (13.3%), and c) segmental onset with initial neck involvement (8.2%).Frequency of spread from focal cervical to segmental dystonia (22.8%) was consistent with prior reports, but frequency of segmental onset with initial neck involvement was substantially higher than 3% previously reported. Cervical dystonia with focal neck onset, more than other subtypes, is associated with spread and tremor of any type. Sensory tricks were less frequent in cervical dystonia with segmental components, and segmental cervical onset occurred at an older age. Conclusions Subgroups had modest but significant differences in the clinical characteristics that may represent different clinical entities or pathophysiologic subtypes. These findings are critical for design and implementation of studies to describe, treat, or modify disease progression in idiopathic isolated cervical dystonia. PMID:27753188

Application of CHESS single-bounce capillaries at synchrotron beamlines

NASA Astrophysics Data System (ADS)

Huang, R.; Szebenyi, T.; Pfeifer, M.; Woll, A.; Smilgies, D.-M.; Finkelstein, K.; Dale, D.; Wang, Y.; Vila-Comamala, J.; Gillilan, R.; Cook, M.; Bilderback, D. H.

2014-03-01

Single-bounce capillaries are achromatic X-ray focusing optics that can provide efficient and high demagnification focusing with large numerical apertures. Capillary fabrication at CHESS can be customized according to specific application requirements. Exemplary applications are reviewed in this paper, as well as recent progress on condensers for high-resolution transmission X-ray microscopy and small focal size capillaries.

A comparison of time taken to return to baseline erectile function following focal and whole gland ablative therapies for localized prostate cancer: A systematic review.

PubMed

Faure Walker, Nicholas A; Norris, Joseph M; Shah, Taimur T; Yap, Tet; Cathcart, Paul; Moore, Caroline M; Ahmed, Hashim U; Emberton, Mark; Minhas, Suks

2018-02-01

To systematically review erectile function (EF) outcomes following primary whole gland (WG) and focal ablative therapies for localized prostate cancer to ascertain whether the treatment modality or intended treatment volume affects the time taken to recover baseline EF. A systematic review was performed according to the preferred reporting items for systematic review and meta-analysis statement. Inclusion criteria were men with localized prostate cancer treated with primary, ablative therapy. Primary outcome was the return to baseline EF measured with objective, validated symptoms scores. Secondary outcome was use of phosphodiesterase inhibitors or erectile aids. Meta-analysis was not performed owing to heterogenous outcome measures. Of 222 articles identified in February 2017, 55 studies which reported EF after ablative therapy were identified but only 17 used validated outcome measures and met inclusion criteria. WG cryotherapy was used in 2 studies, WG high-intensity focused ultrasound (HIFU) in 5, focal cryotherapy in 2, focal HIFU in 3, focal phototherapy or laser therapy in 4, vascular-targeted photodynamic therapy in 3, and irreversible electroporation in 2. WG cryotherapy was associated with a significant decline in EF at 6 months with minimal improvement at 36 months. Baseline IIEF-15 of patients undergoing focal HIFU fell 30 points at 1 month but returned to baseline by 6 months. The remaining focal therapies demonstrated minimal or no effect on EF, but the men in these studies had small foci of disease. The review is limited by lack of randomized studies and heterogenous outcome measures. Most studies assessing the outcomes of focal therapy on sexual function were not of high quality, used heterogenous outcomes, and had relatively short follow up, highlighting the need for more robustly designed studies using validated patient reported outcome measures  for comparison. However, FT in general resulted in less effect on EF than WG ablation. Copyright © 2018 Elsevier Inc. All rights reserved.

Noninvasive lifting of arm, thigh, and knee skin with transcutaneous intense focused ultrasound.

PubMed

Alster, Tina S; Tanzi, Elizabeth L

2012-05-01

Transcutaneous intense focused ultrasound is a novel Food and Drug Administration-approved technology for noninvasive skin tightening of the face and neck. No studies have reported on its safety and effectiveness on nonfacial areas. Eighteen paired areas (6 each) on the upper arms, medial thighs, and extensor knees were randomly treated with two different transducers (4.0 MHz, 4.5-mm focal depth and 7.0 MHz, 3.0-mm focal depth). One side was randomly assigned to receive a single pass (single plane) of microthermal coagulation zones over the involved area with the 4.0 MHz, 4.5-mm-depth transducer, and the contralateral side was assigned to receive consecutive single passes (dual plane) using both transducers (4.0 MHz, 4.5-mm depth followed by 7.0 MHz, 3.0-mm depth). Two independent masked assessors determined clinical improvement scores using comparative standardized photographs obtained at baseline and 3 and 6 months after treatment. Subjective assessments of clinical improvement and side effects of treatment were obtained. Global assessment scores revealed significant improvement in all treated areas, with the upper arms and knees demonstrating more skin lifting and tightening than the thighs. Areas receiving dual-plane treatment had slightly better clinical scores than those receiving single-plane treatment in all three sites. Clinical scores from single-plane and dual-plane treated areas continued to improve between 3 and 6 months after treatment. Side effects were mild and transient and included erythema, warmth, and skin tenderness. Rare focal bruising was noted in two patients on the upper arms that resolved within 7 days. No other side effects were reported or observed. Transcutaneous intense focused ultrasound can be safely and effectively used to improve the clinical appearance (texture and contour) of the upper arms, extensor knees, and medial thighs. © 2012 by the American Society for Dermatologic Surgery, Inc. Published by Wiley Periodicals, Inc.

A benchmark theoretical study of the electronic ground state and of the singlet-triplet split of benzene and linear acenes

NASA Astrophysics Data System (ADS)

Hajgató, B.; Szieberth, D.; Geerlings, P.; De Proft, F.; Deleuze, M. S.

2009-12-01

A benchmark theoretical study of the electronic ground state and of the vertical and adiabatic singlet-triplet (ST) excitation energies of benzene (n =1) and n-acenes (C4n+2H2n+4) ranging from naphthalene (n =2) to heptacene (n =7) is presented, on the ground of single- and multireference calculations based on restricted or unrestricted zero-order wave functions. High-level and large scale treatments of electronic correlation in the ground state are found to be necessary for compensating giant but unphysical symmetry-breaking effects in unrestricted single-reference treatments. The composition of multiconfigurational wave functions, the topologies of natural orbitals in symmetry-unrestricted CASSCF calculations, the T1 diagnostics of coupled cluster theory, and further energy-based criteria demonstrate that all investigated systems exhibit a A1g singlet closed-shell electronic ground state. Singlet-triplet (S0-T1) energy gaps can therefore be very accurately determined by applying the principles of a focal point analysis onto the results of a series of single-point and symmetry-restricted calculations employing correlation consistent cc-pVXZ basis sets (X=D, T, Q, 5) and single-reference methods [HF, MP2, MP3, MP4SDQ, CCSD, CCSD(T)] of improving quality. According to our best estimates, which amount to a dual extrapolation of energy differences to the level of coupled cluster theory including single, double, and perturbative estimates of connected triple excitations [CCSD(T)] in the limit of an asymptotically complete basis set (cc-pV∞Z), the S0-T1 vertical excitation energies of benzene (n =1) and n-acenes (n =2-7) amount to 100.79, 76.28, 56.97, 40.69, 31.51, 22.96, and 18.16 kcal/mol, respectively. Values of 87.02, 62.87, 46.22, 32.23, 24.19, 16.79, and 12.56 kcal/mol are correspondingly obtained at the CCSD(T)/cc-pV∞Z level for the S0-T1 adiabatic excitation energies, upon including B3LYP/cc-PVTZ corrections for zero-point vibrational energies. In line with the absence of Peierls distortions, extrapolations of results indicate a vanishingly small S0-T1 energy gap of 0 to ˜4 kcal/mol (˜0.17 eV) in the limit of an infinitely large polyacene.

Image monitoring of pharmaceutical blending processes and the determination of an end point by using a portable near-infrared imaging device based on a polychromator-type near-infrared spectrometer with a high-speed and high-resolution photo diode array detector.

PubMed

Murayama, Kodai; Ishikawa, Daitaro; Genkawa, Takuma; Sugino, Hiroyuki; Komiyama, Makoto; Ozaki, Yukihiro

2015-03-03

In the present study we have developed a new version (ND-NIRs) of a polychromator-type near-infrared (NIR) spectrometer with a high-resolution photo diode array detector, which we built before (D-NIRs). The new version has four 5 W halogen lamps compared with the three lamps for the older version. The new version also has a condenser lens with a shorter focal point length. The increase in the number of the lamps and the shortening of the focal point of the condenser lens realize high signal-to-noise ratio and high-speed NIR imaging measurement. By using the ND-NIRs we carried out the in-line monitoring of pharmaceutical blending and determined an end point of the blending process. Moreover, to determinate a more accurate end point, a NIR image of the blending sample was acquired by means of a portable NIR imaging device based on ND-NIRs. The imaging result has demonstrated that the mixing time of 8 min is enough for homogeneous mixing. In this way the present study has demonstrated that ND-NIRs and the imaging system based on a ND-NIRs hold considerable promise for process analysis.

Expansive focal cemento-osseous dysplasia.

PubMed

Bulut, Emel Uzun; Acikgoz, Aydan; Ozan, Bora; Zengin, Ayse Zeynep; Gunhan, Omer

2012-01-01

To present a case of expansive focal cemento-osseous dysplasia and emphasize the importance of differential diagnosis. Cemento-osseous dysplasia is categorized into three subtypes on the basis of the clinical and radiographic features: Periapical, focal and florid. The focal type exhibits a single site of involvement in any tooth-bearing or edentulous area of the jaws. These lesions are usually asymptomatic; therefore, they are frequently diagnosed incidentally during routine radiographic examinations. Lesions are usually benign, show limited growth, and do not require further surgical intervention, but periodic follow-up is recommended because occasionally, this type of dysplasia progresses into florid osseous dysplasia and simple bone cysts are formed. A 24-year-old female patient was referred to our clinic for swelling in the left edentulous mandibular premolarmolar region and felt discomfort when she wore her prosthetics. She had no pain, tenderness or paresthesia. Clinical examination showed that the swelling in the posterior mandible that was firm, nonfluctuant and covered by normal mucosa. On panoramic radiography and computed tomography, a well defined lesion of approximately 1.5 cm in diameter of mixed density was observed. The swelling increased slightly in size over 2 years making it difficult to use prosthetics and, therefore, the lesion was totally excised under local anesthesia, and surgical specimens were submitted for histopathological examination. The histopathological diagnosis was focal cemento-osseous dysplasia. In the present case, because of the increasing size of the swelling making it difficult to use prosthetics, young age of the patient and localization of the lesion, in the initial examination, cemento-ossifying fibroma was suspected, and the lesion was excised surgically; the histopathological diagnosis confirmed it as focal cemento-osseous dysplasia. We present a case of expansive focal cemento-osseous dysplasia. Differential diagnosis is essential because ossifying fibroma is a real neoplastic entity.

Titan's Stratospheric Water Vapor profile from Cassini CIRS far-infrared Spectra

NASA Astrophysics Data System (ADS)

Cottini, V.; Nixon, C. A.; Achterberg, R. K.; Gorius, N.; Coustenis, A.; Irwin, P. G. J.; Anderson, C. M.; Bjoraker, G. L.; Jennings, D. E.; Flasar, F. M.; Ansty, T. M.

2017-09-01

In this work we present an update of water vapor abundance in Titan's stratosphere through modeling of its emission lines present in the spectral range (100 - 300 cm-1) observed by the Cassini Composite Infrared Spectrometer (CIRS) far-IR Focal Plane 1 (FP1) detector. We model and analyze high spectral resolution (0.5 cm-1) disk and limb observations acquired from December 2004 to December 2016 to determine the water mixing ratio profile. Nadir data and limb data acquired up to 2011 and pointing at two altitudes in Titan's stratosphere (125 and 225 km) have been previously used in [1] to detect water vapor and retrieve its abundance at two limb altitudes. Few years of more data and improved calibrations are now available to further investigate water vapor. In particular, three far-infrared limb integrations were planned and acquired in 2014 and 2016 with CIRS staring at a single altitude (175 km) for longer time. These new data provided us with one more altitude point to derive the water vapor abundance and improve its retrieved vertical profile, increasing significantly the science results. These results will also be compared to previous results and to the latest photochemical models of Titan's oxygen species.

Three-Dimensional Localization of Single Molecules for Super-Resolution Imaging and Single-Particle Tracking

PubMed Central

von Diezmann, Alex; Shechtman, Yoav; Moerner, W. E.

2017-01-01

Single-molecule super-resolution fluorescence microscopy and single-particle tracking are two imaging modalities that illuminate the properties of cells and materials on spatial scales down to tens of nanometers, or with dynamical information about nanoscale particle motion in the millisecond range, respectively. These methods generally use wide-field microscopes and two-dimensional camera detectors to localize molecules to much higher precision than the diffraction limit. Given the limited total photons available from each single-molecule label, both modalities require careful mathematical analysis and image processing. Much more information can be obtained about the system under study by extending to three-dimensional (3D) single-molecule localization: without this capability, visualization of structures or motions extending in the axial direction can easily be missed or confused, compromising scientific understanding. A variety of methods for obtaining both 3D super-resolution images and 3D tracking information have been devised, each with their own strengths and weaknesses. These include imaging of multiple focal planes, point-spread-function engineering, and interferometric detection. These methods may be compared based on their ability to provide accurate and precise position information of single-molecule emitters with limited photons. To successfully apply and further develop these methods, it is essential to consider many practical concerns, including the effects of optical aberrations, field-dependence in the imaging system, fluorophore labeling density, and registration between different color channels. Selected examples of 3D super-resolution imaging and tracking are described for illustration from a variety of biological contexts and with a variety of methods, demonstrating the power of 3D localization for understanding complex systems. PMID:28151646

Pointing and figure control system for a space-based far-IR segmented telescope

NASA Technical Reports Server (NTRS)

Lau, Kenneth

1993-01-01

A pointing and figure control system for two space-based far-IR telescopes, the 10-20 m Large Deployable Reflector and the 3.6 m Submillimeter Intermediate Mission, is described. The figure maintenance control system is designed to counter the optical elements translational and rotational changes induced by long-term thermal drifts that the support structure may experience. The pointing system applies optical truss to telescope pointing; a laser metrology system is used to transfer pointing informaton from an external fine guidance sensor to the telescope optical boresight, defined by the primary mirror, secondary mirror, and focal plane assembly.

The Unicellular State as a Point Source in a Quantum Biological System

PubMed Central

Torday, John S.; Miller, William B.

2016-01-01

A point source is the central and most important point or place for any group of cohering phenomena. Evolutionary development presumes that biological processes are sequentially linked, but neither directed from, nor centralized within, any specific biologic structure or stage. However, such an epigenomic entity exists and its transforming effects can be understood through the obligatory recapitulation of all eukaryotic lifeforms through a zygotic unicellular phase. This requisite biological conjunction can now be properly assessed as the focal point of reconciliation between biology and quantum phenomena, illustrated by deconvoluting complex physiologic traits back to their unicellular origins. PMID:27240413

Photothrombosis-Induced Infarction of the Mouse Cerebral Cortex Is Not Affected by the Nrf2-Activator Sulforaphane

PubMed Central

Hou, Linda; Nilsson, Åsa; Pekna, Marcela; Pekny, Milos; Nilsson, Michael

2012-01-01

Sulforaphane-induced activation of the transcription factor NF-E2 related factor 2 (Nrf2 or the gene Nfe2l2) and subsequent induction of the phase II antioxidant system has previously been shown to exert neuroprotective action in a transient model of focal cerebral ischemia. However, its ability to attenuate functional and cellular deficits after permanent focal cerebral ischemia is not clear. We assessed the neuroprotective effects of sulforaphane in the photothrombotic model of permanent focal cerebral ischemia. Sulforaphane was administered (5 or 50 mg/kg, i.p.) after ischemic onset either as a single dose or as daily doses for 3 days. Sulforaphane increased transcription of Nrf2, Hmox1, GCLC and GSTA4 mRNA in the brain confirming activation of the Nrf2 system. Single or repeated administration of sulforaphane had no effect on the infarct volume, nor did it reduce the number of activated glial cells or proliferating cells when analyzed 24 and 72 h after stroke. Motor-function as assessed by beam-walking, cylinder-test, and adhesive test, did not improve after sulforaphane treatment. The results show that sulforaphane treatment initiated after photothrombosis-induced permanent cerebral ischemia does not interfere with key cellular mechanisms underlying tissue damage. PMID:22911746

Photothrombosis-induced infarction of the mouse cerebral cortex is not affected by the Nrf2-activator sulforaphane.

PubMed

Porritt, Michelle J; Andersson, Helene C; Hou, Linda; Nilsson, Åsa; Pekna, Marcela; Pekny, Milos; Nilsson, Michael

2012-01-01

Sulforaphane-induced activation of the transcription factor NF-E2 related factor 2 (Nrf2 or the gene Nfe2l2) and subsequent induction of the phase II antioxidant system has previously been shown to exert neuroprotective action in a transient model of focal cerebral ischemia. However, its ability to attenuate functional and cellular deficits after permanent focal cerebral ischemia is not clear. We assessed the neuroprotective effects of sulforaphane in the photothrombotic model of permanent focal cerebral ischemia. Sulforaphane was administered (5 or 50 mg/kg, i.p.) after ischemic onset either as a single dose or as daily doses for 3 days. Sulforaphane increased transcription of Nrf2, Hmox1, GCLC and GSTA4 mRNA in the brain confirming activation of the Nrf2 system. Single or repeated administration of sulforaphane had no effect on the infarct volume, nor did it reduce the number of activated glial cells or proliferating cells when analyzed 24 and 72 h after stroke. Motor-function as assessed by beam-walking, cylinder-test, and adhesive test, did not improve after sulforaphane treatment. The results show that sulforaphane treatment initiated after photothrombosis-induced permanent cerebral ischemia does not interfere with key cellular mechanisms underlying tissue damage.

Focal neurological deficits

MedlinePlus

... include: Abnormal blood vessels (vascular malformation) Brain tumor Cerebral palsy Degenerative nerve illness (such as multiple sclerosis) Disorders of a single nerve or nerve group (for example, carpal tunnel syndrome ) Infection of the brain (such as meningitis or encephalitis) Injury Stroke Home ...

The Role of Law in Adaptive Governance

EPA Science Inventory

The term “governance” encompasses both governmental and nongovernmental participation in collective choice and action. Law dictates the structure, boundaries, rules, and processes within which governmental action takes place, and in doing so becomes one of the focal points for an...

Options for enhancing the effectiveness of Virginia's safety management system : final report.

DOT National Transportation Integrated Search

1996-02-01

In 1993, Virginia began to formalize the relationships and organizational structure for its Safety Management System (SMS). Although the SMS is no longer a federal requirement, Virginia decided to continue its implementation. The Focal Point for the ...

Richard Wright: Climate of Fear and Violence.

ERIC Educational Resources Information Center

Nnaemeka, Obioma

1992-01-01

In his works, Richard Wright denounces murder while advocating collectivism as an essential ingredient for effecting social change. The short story collection "Uncle Tom's Children" and the novel "Native Son" are the focal points in this analysis of Wright's recurring themes. (SLD)

47 CFR 215.1 - Background.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 5 2012-10-01 2012-10-01 false Background. 215.1 Section 215.1 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL FEDERAL GOVERNMENT FOCAL POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.1 Background. (a) The nuclear electromagnetic...

47 CFR 215.1 - Background.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 5 2014-10-01 2014-10-01 false Background. 215.1 Section 215.1 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL FEDERAL GOVERNMENT FOCAL POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.1 Background. (a) The nuclear electromagnetic...

47 CFR 215.1 - Background.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Background. 215.1 Section 215.1 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL FEDERAL GOVERNMENT FOCAL POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.1 Background. (a) The nuclear electromagnetic...

47 CFR 215.1 - Background.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 5 2013-10-01 2013-10-01 false Background. 215.1 Section 215.1 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL FEDERAL GOVERNMENT FOCAL POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.1 Background. (a) The nuclear electromagnetic...

47 CFR 215.1 - Background.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 5 2011-10-01 2011-10-01 false Background. 215.1 Section 215.1 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL FEDERAL GOVERNMENT FOCAL POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.1 Background. (a) The nuclear electromagnetic...

Direct view zoom scope with single focal plane and adaptable reticle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bagwell, Brett

A direct view telescopic sight includes objective lens, eyepiece, and prism erector assemblies. The objective lens assembly is mounted to receive light of an image from an object direction and direct the light along an optical path. The eyepiece assembly is mounted to receive the light along the optical path and to emit the light of the image along an eye-ward direction. The prism erector assembly is positioned between the objective lens and eyepiece assemblies and includes first and second prism elements through which the optical path passes. The first and second prism elements invert the image. A reticle elementmore » is disposed on or adjacent to a surface of one of the first or second prism elements to combine a reticle on the image. The image is brought into focus at only a single focal plane between the objective lens and eyepiece assemblies at a given time.« less

Specific features of direct formation of graphite-like microstructures in polycarbonate samples by single femtosecond laser pulses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ganin, D V; Lapshin, K E; Obidin, A Z

2015-11-30

We present the result of the experiments on producing graphite-like cylindrical microstructures by focusing single femtosecond laser pulses into the bulk of a transparent polymer (polycarbonate). The microstructures are embedded in a cladding with a modified refractive index, possessing waveguide properties. In the experiments with nontransparent screens and diaphragms, placed in the laser beam in front of the entrance pupil of the objective with a large numerical aperture, we have found that the paraxial rays are blocked by the peripheral ones, which reduces the length of the destruction region in the pre-focal zone. In the experiments with transparent screens andmore » diaphragms, introducing optical delays τ{sub d} between the paraxial and peripheral rays, the quantitative dependence of the destruction region length in the pre-focal zone on the value of τ{sub d} is determined. (interaction of laser radiation with matter. laser plasma)« less

Air-clad fibres for astronomical instrumentation: focal-ratio degradation

NASA Astrophysics Data System (ADS)

Åslund, Mattias L.; Canning, John

2009-05-01

Focal-ratio degradation (FRD) of light launched into high-numerical aperture (NA) single-annulus all-silica undoped air-clad fibres at an NA of 0.54 is reported. The measured annular light distribution remained Gaussian after 30 m of propagation, but the angular FWHM of the output annulus doubled from 4° after 1 m propagation to 8.5° after 30 m, which is significantly larger than that reported of standard doped-silica fibres (NA < 0.22). No significant diffractive effects were observed. The design of air-clad fibres for broad-band, high-NA astrophotonics applications is discussed.

NGS2: a focal plane array upgrade for the GeMS multiple tip-tilt wavefront sensor

NASA Astrophysics Data System (ADS)

Rigaut, François; Price, Ian; d'Orgeville, Céline; Bennet, Francis; Herrald, Nick; Paulin, Nicolas; Uhlendorf, Kristina; Garrel, Vincent; Sivo, Gaetano; Montes, Vanessa; Trujillo, Chad

2016-07-01

NGS2 is an upgrade for the multi-natural guide star tip-tilt & plate scale wavefront sensor for GeMS (Gemini Multi-Conjugate Adaptive Optics system). It uses a single Nüvü HNü-512 Electron-Multiplied CCD array that spans the entire GeMS wavefront sensor focal plane. Multiple small regions-of-interest are used to enable frame rates up to 800Hz. This set up will improve the optical throughput with respect to the current wavefront sensor, as well as streamline acquisition and allow for distortion compensation.

Initial experience with SPECT imaging of the brain using I-123 p-iodoamphetamine in focal epilepsy

DOE Office of Scientific and Technical Information (OSTI.GOV)

LaManna, M.M.; Sussman, N.M.; Harner, R.N.

1989-06-01

Nineteen patients with complex partial seizures refractory to medical treatment were examined with routine electroencephalography (EEG), video EEG monitoring, computed tomography or magnetic resonance imaging, neuropsychological tests and interictal single photon emission computed tomography (SPECT) with I-123 iodoamphetamine (INT). In 18 patients, SPECT identified areas of focal reduction in tracer uptake that correlated with the epileptogenic focus identified on the EEG. In addition, SPECT disclosed other areas of neurologic dysfunction as elicited on neuropsychological tests. Thus, IMP SPECT is a useful tool for localizing epileptogenic foci and their associated dynamic deficits.

Simultaneous occurrence of focal nodular hyperplasia and HNF1A-inactivated hepatocellular adenoma: a collision tumor simulating a composite FNH-HCA.

PubMed

Shih, Angela; Lauwers, Gregory Y; Balabaud, Charles; Bioulac-Sage, Paulette; Misdraji, Joseph

2015-09-01

Mixed focal nodular hyperplasia (FNH) and hepatocellular adenoma (HCA) within a single tumor mass is rarely reported, and most of these cases are examples of tumors with features intermediate between FNH and HCA. Although a few reported cases are probably examples of true mixed tumors, none was evaluated immunohistochemically or confirmed by molecular analysis. We report a mixed FNH and HCA arising in a woman with several HNF1A-inactivated adenomas. Our case is the first case of mixed FNH and HNF1A-inactivated HCA documented by immunohistochemistry.

Design of a bullet beam pattern of a micro ultrasound transducer (Conference Presentation)

NASA Astrophysics Data System (ADS)

Roh, Yongrae; Lee, Seongmin

2016-04-01

Ultrasonic imaging transducer is often required to compose a beam pattern of a low sidelobe level and a small beam width over a long focal region to achieve good image resolution. Normal ultrasound transducers have many channels along its azimuth, which allows easy formation of the sound beam into a desired shape. However, micro-array transducers have no control of the beam pattern along their elevation. In this work, a new method is proposed to manipulate the beam pattern by using an acoustic multifocal lens and a shaded electrode on top of the piezoelectric layer. The shading technique split an initial uniform electrode into several segments and combined those segments to compose a desired beam pattern. For a given elevation width and frequency, the optimal pattern of the split electrodes was determined by means of the OptQuest-Nonlinear Program (OQ-NLP) algorithm to achieve the lowest sidelobe level. The requirement to achieve a small beam width with a long focal region was satisfied by employing an acoustic lens of three multiple focuses. Optimal geometry of the multifocal lens such as the radius of curvature and aperture diameter for each focal point was also determined by the OQ-NLP algorithm. For the optimization, a new index was devised to evaluate the on-axis response: focal region ratio = focal region / minimum beam width. The larger was the focal region ratio, the better was the beam pattern. Validity of the design has been verified through fabricating and characterizing an experimental prototype of the transducer.

Aberration Theory and Design Techniques for Refracting Prism Systems.

NASA Astrophysics Data System (ADS)

Al-Bizri, N.

Available from UMI in association with The British Library. The general case of image formation by optical systems consisting of combinations of ordinary lens components and refracting prisms is studied in detail. Formulae for the sagittal and tangential magnifications, the pupil scale ratios, the image tilt, the positions of (newly defined) principal planes and the equivalent focal lengths have been derived. Formulae for the axial astigmatism, axial transverse chromatic aberration and the focal shift measure of the aberration due to the tilt of the image plane have also been obtained. All of these formulae are equally valid for any optical system which has a single plane of symmetry. The calculation of the wavefront aberration coefficients and of the variance of the aberration for such systems has been treated using the pre-inverted matrix method. In addition formulae for the numerical evaluation of the optical transfer function, the point spread function, the line spread function and the edge response function, have been obtained and programmed. First-order formulae, and a refinement technique, for the design of cemented refracting doublet prisms have been obtained, which ensure that the desired prismatic deviation of the axis is obtained, and that the axial astigmatism and the axial transverse chromatic aberration have stipulated target values. All of the above formulae have been carefully tested by numerical examples, and the design technique has been used to design endoscope objectives which provide small deviations (<10^circ ) of the optical axis.

Categorisation of Colour Terms Using New Validation Tools: A Case Study and Implications

PubMed Central

Arbab, Shabnam; Brindle, Jonathan A.; Matusiak, Barbara S.; Klöckner, Christian A.

2018-01-01

This article elaborates on the results of a field experiment conducted among speakers of the Chakali language, spoken in northern Ghana. In the original study, the Color-aid Corporation Chart was used to perform the focal task in which consultants were asked to point at a single colour tile on the chart. However, data from the focal task could not be analysed since the Color-aid tiles had not yet been converted into numerical values set forth by the Commission internationale de l’éclairage (CIE). In this study, the full set of 314 Color-aid tiles were measured for chromaticity and converted into the CIE values at the Daylight Laboratory of the Norwegian University of Science and Technology. This article presents the conversion methodology and makes the results of the measurements, which are available in the Online Appendix. We argue that some visual-perception terms cannot be reliably ascribed to colour categories established by the Color-aid Corporation. This suggests that the ideophonic expressions in the dataset do not denote ‘colours’, as categorised in the Color-aid system, as it was impossible to average the consultants’ data into a CIE chromaticity diagram, illustrate the phenomena on the Natural Colour System (NCS) Circle and Triangle diagrams, and conduct a statistical analysis. One of the implications of this study is that a line between a visual-perception term and a colour term could be systematically established using a method with predefined categorical thresholds. PMID:29755718

Categorisation of Colour Terms Using New Validation Tools: A Case Study and Implications.

PubMed

Arbab, Shabnam; Brindle, Jonathan A; Matusiak, Barbara S; Klöckner, Christian A

2018-01-01

This article elaborates on the results of a field experiment conducted among speakers of the Chakali language, spoken in northern Ghana. In the original study, the Color-aid Corporation Chart was used to perform the focal task in which consultants were asked to point at a single colour tile on the chart. However, data from the focal task could not be analysed since the Color-aid tiles had not yet been converted into numerical values set forth by the Commission internationale de l'éclairage (CIE). In this study, the full set of 314 Color-aid tiles were measured for chromaticity and converted into the CIE values at the Daylight Laboratory of the Norwegian University of Science and Technology. This article presents the conversion methodology and makes the results of the measurements, which are available in the Online Appendix. We argue that some visual-perception terms cannot be reliably ascribed to colour categories established by the Color-aid Corporation. This suggests that the ideophonic expressions in the dataset do not denote 'colours', as categorised in the Color-aid system, as it was impossible to average the consultants' data into a CIE chromaticity diagram, illustrate the phenomena on the Natural Colour System (NCS) Circle and Triangle diagrams, and conduct a statistical analysis. One of the implications of this study is that a line between a visual-perception term and a colour term could be systematically established using a method with predefined categorical thresholds.

On the dual-cone nature of the conical refraction phenomenon.

PubMed

Turpin, A; Loiko, Yu; Kalkandjiev, T K; Tomizawa, H; Mompart, J

2015-04-15

In conical refraction (CR), a focused Gaussian input beam passing through a biaxial crystal and parallel to one of the optic axes is transformed into a pair of concentric bright rings split by a dark (Poggendorff) ring at the focal plane. Here, we show the generation of a CR transverse pattern that does not present the Poggendorff fine splitting at the focal plane, i.e., it forms a single light ring. This light ring is generated from a nonhomogeneously polarized input light beam obtained by using a spatially inhomogeneous polarizer that mimics the characteristic CR polarization distribution. This polarizer allows modulating the relative intensity between the two CR light cones in accordance with the recently proposed dual-cone model of the CR phenomenon. We show that the absence of interfering rings at the focal plane is caused by the selection of one of the two CR cones.

[Focal myositis: An unknown disease].

PubMed

Gallay, L; Streichenberger, N; Benveniste, O; Allenbach, Y

2017-10-01

Focal myositis are inflammatory muscle diseases of unknown origin. At the opposite from the other idiopathic inflammatory myopathies, they are restricted to a single muscle or to a muscle group. They are not associated with extramuscular manifestations, and they have a good prognosis without any treatment. They are characterized by a localized swelling affecting mostly lower limbs. The pseudo-tumor can be painful, but is not associated with a muscle weakness. Creatine kinase level is normal. Muscle MRI shows an inflammation restricted to a muscle or a muscle group. Muscle biopsy and pathological analysis remain necessary for the diagnosis, showing inflammatory infiltrates composed by macrophages and lymphocytes without any specific distribution within the muscle. Focal overexpression of HLA-1 by the muscle fibers is frequently observed. The muscle biopsy permits to rule out differential diagnosis such a malignancy (sarcoma). Spontaneous remission occurs within weeks or months after the first symptoms, relapse is unusual. Copyright © 2017. Published by Elsevier SAS.

Case report: A rare case of focal myositis presenting as Sartorius muscle contracture: A case report and review of literature.

PubMed

Wang, Jin; Jiao, Juyang; Zhao, Guanglei; Shi, Jingsheng; Xia, Jun

2018-05-01

Focal myositis (FM) is a very rare myopathy of unknown etiology characterized by focal enlargement within one single skeletal muscle. In particular, it occurs only involving the Sartorius muscle has never been reported. A 25-year-old man was admitted to the hospital with progressive restricted left hip joint extension, left thigh discomfort and gait disturbance for 6 years. Combining clinical manifestations with results of radiological and pathological examinations, it was consistent with the diagnosis of FM INTERVENTIONS:: The patient received a surgery under general anesthesia to release the contracted Sartorius tendon. The range of motion of the patient's left hip and ipsilateral knee has significantly improved as well as the discomfort of his left thigh relieved obviously after the surgery. This case report is the first to report FM presenting as sartorius muscle contracture and the surgery is an alternative therapy for these patients.

Adaptive multiphoton endomicroscopy through a dynamically deformed multicore optical fiber using proximal detection.

PubMed

Warren, Sean C; Kim, Youngchan; Stone, James M; Mitchell, Claire; Knight, Jonathan C; Neil, Mark A A; Paterson, Carl; French, Paul M W; Dunsby, Chris

2016-09-19

This paper demonstrates multiphoton excited fluorescence imaging through a polarisation maintaining multicore fiber (PM-MCF) while the fiber is dynamically deformed using all-proximal detection. Single-shot proximal measurement of the relative optical path lengths of all the cores of the PM-MCF in double pass is achieved using a Mach-Zehnder interferometer read out by a scientific CMOS camera operating at 416 Hz. A non-linear least squares fitting procedure is then employed to determine the deformation-induced lateral shift of the excitation spot at the distal tip of the PM-MCF. An experimental validation of this approach is presented that compares the proximally measured deformation-induced lateral shift in focal spot position to an independent distally measured ground truth. The proximal measurement of deformation-induced shift in focal spot position is applied to correct for deformation-induced shifts in focal spot position during raster-scanning multiphoton excited fluorescence imaging.

STROBE-X: X-ray Timing & Spectroscopy on Dynamical Timescales from Milliseconds to Years

NASA Technical Reports Server (NTRS)

Wilson-Hodge, Colleen A.; Ray, P. S.; Maccarone, T; Chakrabarty, D.; Gendreau, K.; Arzoumanian, Z.; Jenke, P.; Ballantyne, D.; Bozzo, E.; Brandt, S.;

STROBE-X: X-Ray Timing Spectroscopy on Dynamical Timescales from Microseconds to Years

NASA Technical Reports Server (NTRS)

Wilson-Hodge, Colleen A.; Ray, P. S.; Gendreau, K.; Arzoumanian, Z.; Chakrabarty, D.; Remillard, R.; Feroci, M.; Maccarone, T.; Wood, K.; Jenke, P.

2017-01-01

We describe a probe-class mission concept that provides an unprecedented view of the X-ray sky, performing timing and 0.2-30 keV spectroscopy over timescales from microseconds to years. The Spectroscopic Time-Resolving Observatory for Broadband Energy X-rays (STROBE-X) comprises three primary instruments. The first uses an array of lightweight optics (3-m focal length) that concentrate incident photons onto solid state detectors with CCD-level (85-130 eV) energy resolution, 100 ns time resolution, and low background rates to cover the 0.2-12 keV band. This technology is scaled up from NICER, with enhanced optics to take advantage of the longer focal length of STROBE-X. The second uses large-area collimated silicon drift detectors, developed for ESA's LOFT, to cover the 2-30 keV band. These two instruments each provide an order of magnitude improvement in effective area compared with its predecessor (NICER and RXTE, respectively). Finally, a sensitive sky monitor triggers pointed observations, provides high duty cycle, high time resolution, high spectral resolution monitoring of the X-ray sky with approx. 20 times the sensitivity of the RXTE ASM, and enables multi-wavelength and multi-messenger studies on a continuous, rather than scanning basis.For the first time, the broad coverage provides simultaneous study of thermal components, non-thermal components, iron lines, and reflection features from a single platform for accreting black holes at all scales. The enormous collecting area allows detailed studies of the dense matter equation of state using both thermal emission from rotation-powered pulsars and harder emission from X-ray burst oscillations. The combination of the wide-field monitor and the sensitive pointed instruments enables observations of potential electromagnetic counterparts to LIGO and neutrino events. Additional extragalactic science, such as high quality spectroscopy of clusters of galaxies and unprecedented timing investigations of active galactic nuclei, is also obtained.

Image reconstruction from cone-beam projections with attenuation correction

NASA Astrophysics Data System (ADS)

Weng, Yi

1997-07-01

In single photon emission computered tomography (SPECT) imaging, photon attenuation within the body is a major factor contributing to the quantitative inaccuracy in measuring the distribution of radioactivity. Cone-beam SPECT provides improved sensitivity for imaging small organs. This thesis extends the results for 2D parallel- beam and fan-beam geometry to 3D parallel-beam and cone- beam geometries in order to derive filtered backprojection reconstruction algorithms for the 3D exponential parallel-beam transform and for the exponential cone-beam transform with sampling on a sphere. An exact inversion formula for the 3D exponential parallel-beam transform is obtained and is extended to the 3D exponential cone-beam transform. Sampling on a sphere is not useful clinically and current cone-beam tomography, with the focal point traversing a planar orbit, does not acquire sufficient data to give an accurate reconstruction. Thus a data acquisition method that obtains complete data for cone-beam SPECT by simultaneously rotating the gamma camera and translating the patient bed, so that cone-beam projections can be obtained with the focal point traversing a helix that surrounds the patient was developed. First, an implementation of Grangeat's algorithm for helical cone- beam projections was developed without attenuation correction. A fast new rebinning scheme was developed that uses all of the detected data to reconstruct the image and properly normalizes any multiply scanned data. In the case of attenuation no theorem analogous to Tuy's has been proven. We hypothesized that an artifact-free reconstruction could be obtained even if the cone-beam data are attenuated, provided the imaging orbit satisfies Tuy's condition and the exact attenuation map is known. Cone-beam emission data were acquired by using a circle- and-line and a helix orbit on a clinical SPECT system. An iterative conjugate gradient reconstruction algorithm was used to reconstruct projection data with a known attenuation map. The quantitative accuracy of the attenuation-corrected emission reconstruction was significantly improved.

STROBE-X: X-ray Timing & Spectroscopy on Dynamical Timescales from Microseconds to Years

NASA Astrophysics Data System (ADS)

Wilson-Hodge, Colleen A.; Ray, Paul S.; Gendreau, Keith; Chakrabarty, Deepto; Feroci, Marco; Maccarone, Thomas J.; Arzoumanian, Zaven; Remillard, Ronald A.; Wood, Kent; Griffith, Christopher; Jenke, Peter

2017-08-01

We describe a probe-class mission concept that provides an unprecedented view of the X-ray sky, performing timing and 0.2-30 keV spectroscopy over timescales from microseconds to years. The Spectroscopic Time-Resolving Observatory for Broadband Energy X-rays (STROBE-X) comprises three primary instruments. The first uses an array of lightweight optics (3-m focal length) that concentrate incident photons onto solid state detectors with CCD-level (85-130 eV) energy resolution, 100 ns time resolution, and low background rates to cover the 0.2-12 keV band. This technology is scaled up from NICER, with enhanced optics to take advantage of the longer focal length of STROBE-X. The second uses large-area collimated silicon drift detectors, developed for ESA's LOFT, to cover the 2-30 keV band. These two instruments each provide an order of magnitude improvement in effective area compared with its predecessor (NICER and RXTE, respectively). Finally, a sensitive sky monitor triggers pointed observations, provides high duty cycle, high time resolution, high spectral resolution monitoring of the X-ray sky with ~20 times the sensitivity of the RXTE ASM, and enables multi-wavelength and multi-messenger studies on a continuous, rather than scanning basis.For the first time, the broad coverage provides simultaneous study of thermal components, non-thermal components, iron lines, and reflection features from a single platform for accreting black holes at all scales. The enormous collecting area allows detailed studies of the dense matter equation of state using both thermal emission from rotation-powered pulsars and harder emission from X-ray burst oscillations. The combination of the wide-field monitor and the sensitive pointed instruments enables observations of potential electromagnetic counterparts to LIGO and neutrino events. Additional extragalactic science, such as high quality spectroscopy of clusters of galaxies and unprecedented timing investigations of active galactic nuclei, is also obtained.

Pharmacokinetic Study of Piracetam in Focal Cerebral Ischemic Rats.

PubMed

Paliwal, Pankaj; Dash, Debabrata; Krishnamurthy, Sairam

2018-04-01

Cerebral ischemia affects hepatic enzymes and brain permeability extensively. Piracetam was investigated up to phase III of clinical trials and there is lack of data on brain penetration in cerebral ischemic condition. Thus, knowledge of the pharmacokinetics and brain penetration of piracetam during ischemic condition would aid to improve pharmacotherapeutics in ischemic stroke. Focal cerebral ischemia was induced by middle cerebral artery occlusion for 2 h in male Wistar rats followed by reperfusion. After 24 h of middle cerebral artery occlusion or 22 h of reperfusion, piracetam was administered for pharmacokinetic, brain penetration, and pharmacological experiments. In pharmacokinetic study, blood samples were collected at different time points after 200-mg/kg (oral) and 75-mg/kg (intravenous) administration of piracetam through right external jugular vein cannulation. In brain penetration study, the cerebrospinal fluid, systemic blood, portal blood, and brain samples were collected at pre-designated time points after 200-mg/kg oral administration of piracetam. In a separate experiment, the pharmacological effect of the single oral dose of piracetam in middle cerebral artery occlusion was assessed at a dose of 200 mg/kg. All the pharmacokinetic parameters of piracetam including area under curve (AUC 0-24 ), maximum plasma concentration (C max ), time to reach the maximum plasma concentration (t max ), elimination half-life (t 1/2 ), volume of distribution (V z ), total body clearance, mean residence time, and bioavailability were found to be similar in ischemic stroke condition except for brain penetration. Piracetam exposure (AUC 0-2 ) in brain and CSF were found to be 2.4- and 3.1-fold higher, respectively, in ischemic stroke compared to control rats. Piracetam significantly reduced infarct volume by 35.77% caused by middle cerebral artery occlusion. There was no change in the pharmacokinetic parameters of piracetam in the ischemic stroke model except for brain penetration. This indicates that variables influencing brain penetration may not be limiting factors for use of piracetam in ischemic stroke.

Perpetuation of torsade de pointes in heterogeneous hearts: competing foci or re-entry?

PubMed

Vandersickel, Nele; de Boer, Teun P; Vos, Marc A; Panfilov, Alexander V

2016-12-01

The underlying mechanism of torsade de pointes (TdP) remains of debate: perpetuation may be due to (1) focal activity or (2) re-entrant activity. The onset of TdP correlates with action potential heterogeneities in different regions of the heart. We studied the mechanism of perpetuation of TdP in silico using a 2D model of human cardiac tissue and an anatomically accurate model of the ventricles of the human heart. We found that the mechanism of perpetuation TdP depends on the degree of heterogeneity. If the degree of heterogeneity is large, focal activity alone can sustain a TdP, otherwise re-entrant activity emerges. This result can help to understand the relationship between the mechanisms of TdP and tissue properties and may help in developing new drugs against it. Torsade de pointes (TdP) can be the consequence of cardiac remodelling, drug effects or a combination of both. The mechanism underlying TdP is unclear, and may involve triggered focal activity or re-entry. Recent work by our group has indicated that both cases may exist, i.e. TdPs induced in the chronic atrioventricular block (CAVB) dog model may have a focal origin or are due to re-entry. Also it was found that heterogeneities might play an important role. In the current study we have used computational modelling to further investigate the mechanisms involved in TdP initiation and perpetuation, especially in the CAVB dog model, by the addition of heterogeneities with reduced repolarization reserve in comparison with the surrounding tissue. For this, the TNNP computer model was used for computations. We demonstrated in 2D and 3D simulations that ECGs with the typical TdP morphology can be caused by both multiple competing foci and re-entry circuits as a result of introduction of heterogeneities, depending on whether the heterogeneities have a large or a smaller reduced repolarization reserve in comparison with the surrounding tissue. Large heterogeneities can produce ectopic TdP, while smaller heterogeneities will produce re-entry-type TdP. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

Focal ratio degradation in lightly fused hexabundles

NASA Astrophysics Data System (ADS)

Bryant, J. J.; Bland-Hawthorn, J.; Fogarty, L. M. R.; Lawrence, J. S.; Croom, S. M.

2014-02-01

We are now moving into an era where multi-object wide-field surveys, which traditionally use single fibres to observe many targets simultaneously, can exploit compact integral field units (IFUs) in place of single fibres. Current multi-object integral field instruments such as Sydney-AAO Multi-object Integral field spectrograph have driven the development of new imaging fibre bundles (hexabundles) for multi-object spectrographs. We have characterized the performance of hexabundles with different cladding thicknesses and compared them to that of the same type of bare fibre, across the range of fill fractions and input f-ratios likely in an IFU instrument. Hexabundles with 7-cores and 61-cores were tested for focal ratio degradation (FRD), throughput and cross-talk when fed with inputs from F/3.4 to >F/8. The five 7-core bundles have cladding thickness ranging from 1 to 8 μm, and the 61-core bundles have 5 μm cladding. As expected, the FRD improves as the input focal ratio decreases. We find that the FRD and throughput of the cores in the hexabundles match the performance of single fibres of the same material at low input f-ratios. The performance results presented can be used to set a limit on the f-ratio of a system based on the maximum loss allowable for a planned instrument. Our results confirm that hexabundles are a successful alternative for fibre imaging devices for multi-object spectroscopy on wide-field telescopes and have prompted further development of hexabundle designs with hexagonal packing and square cores.

Economic growth or no growth. [Needs to get to year 2000

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vanderslice, T.A.

1978-12-01

Dr. Vanderslice points out that, for much of this century, energy growth and GNP have marched in lockstep, and the relationship appears to be causal, not casual. Showing the economic impacts of an energy shortfall, he feels that unless both industry and government recognize increasing energy consumption as a reality--even with conservation--they are irresponsible planners. He further points out that those who would lead us down alternative energy paths offer little assurance that the paths do not end short of our goals; and that a characteristic of most of these plans is the notable lack of detailed road maps andmore » planning. Seeing a crying need for thorough revision of our present system of licensing and regulating power plants, Dr. Vanderslice favors placing greater authority with the states, since each state has different environmental and energy problems. Citing nuclear power as a focal point since it welds so many current movements-- consumerism, environmentalism, anti-technology, decentralization, and regulation--into a single issue, he says the real issue is growth vs. no-growth and may be decided de facto by the constriction of our energy options. Further, given that the world's population and ours will continue to grow, there is no acceptable alternative to the increasing use of energy as a basic reality of human existence.« less

Direct generation of abruptly focusing vortex beams using a 3/2 radial phase-only pattern.

PubMed

Davis, Jeffrey A; Cottrell, Don M; Zinn, Jonathan M

2013-03-20

Abruptly focusing Airy beams have previously been generated using a radial cubic phase pattern that represents the Fourier transform of the Airy beam. The Fourier transform of this pattern is formed using a system length of 2f, where f is the focal length of the Fourier transform lens. In this work, we directly generate these abruptly focusing Airy beams using a 3/2 radial phase pattern encoded onto a liquid crystal display. The resulting optical system is much shorter. In addition, we can easily produce vortex patterns at the focal point of these beams. Experimental results match theoretical predictions.

Public transit to public lands : the nature express.

DOT National Transportation Integrated Search

2017-05-01

Access to leisure by public transportation has not been studied in great detail, at least in the United States. The Northeastern Illinois region with the City of Chicago (in Cook County) as the focal point is home to the third largest public transpor...

42 CFR 460.6 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... a facility which includes a primary care clinic, and areas for therapeutic recreation, restorative therapies, socialization, personal care, and dining, and which serves as the focal point for coordination... ALL-INCLUSIVE CARE FOR THE ELDERLY (PACE) PROGRAMS OF ALL-INCLUSIVE CARE FOR THE ELDERLY (PACE) Basis...

42 CFR 460.6 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... a facility which includes a primary care clinic, and areas for therapeutic recreation, restorative therapies, socialization, personal care, and dining, and which serves as the focal point for coordination... ALL-INCLUSIVE CARE FOR THE ELDERLY (PACE) PROGRAMS OF ALL-INCLUSIVE CARE FOR THE ELDERLY (PACE) Basis...

42 CFR 460.6 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... a facility which includes a primary care clinic, and areas for therapeutic recreation, restorative therapies, socialization, personal care, and dining, and which serves as the focal point for coordination... ALL-INCLUSIVE CARE FOR THE ELDERLY (PACE) PROGRAMS OF ALL-INCLUSIVE CARE FOR THE ELDERLY (PACE) Basis...

The Federal Employees' Compensation Act.

ERIC Educational Resources Information Center

Nordlund, Willis J.

1991-01-01

The 1916 Federal Employees' Compensation Act is still the focal point around which the federal workers compensation program works today. The program has gone through many changes on its way to becoming a modern means of compensating workers for job-related injury, disease, and death. (Author)

Chariots for Apollo: A History of Manned Lunar Spacecraft

NASA Technical Reports Server (NTRS)

Brooks, C. G.; Grimwood, J. M.; Swenson, L. S., Jr.

1979-01-01

Beginning with the challenges presented by Sputnik 1 in 1957, and the formation of NASA, the apollo lunar exploration program is reviewed through Apollo Flight 11. The focal points are the spacecraft including the command and service modules, and the lunar module.

47 CFR 215.2 - Assignment of responsibilities.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 5 2013-10-01 2013-10-01 false Assignment of responsibilities. 215.2 Section 215.2 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL FEDERAL GOVERNMENT FOCAL POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.2 Assignment of responsibilities...

47 CFR 215.2 - Assignment of responsibilities.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 5 2012-10-01 2012-10-01 false Assignment of responsibilities. 215.2 Section 215.2 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL FEDERAL GOVERNMENT FOCAL POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.2 Assignment of responsibilities...

47 CFR 215.2 - Assignment of responsibilities.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Assignment of responsibilities. 215.2 Section 215.2 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL FEDERAL GOVERNMENT FOCAL POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.2 Assignment of responsibilities...

47 CFR 215.2 - Assignment of responsibilities.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 5 2014-10-01 2014-10-01 false Assignment of responsibilities. 215.2 Section 215.2 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL FEDERAL GOVERNMENT FOCAL POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.2 Assignment of responsibilities...

47 CFR 215.2 - Assignment of responsibilities.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 5 2011-10-01 2011-10-01 false Assignment of responsibilities. 215.2 Section 215.2 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL FEDERAL GOVERNMENT FOCAL POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.2 Assignment of responsibilities...

Taylorism and the Logic of Learning Outcomes

ERIC Educational Resources Information Center

Stoller, Aaron

2015-01-01

This essay examines the shared philosophical foundations of Fredrick W. Taylor's scientific management principles and the contemporary learning outcomes movement (LOM). It analyses the shared philosophical ground between the focal point of Taylor's system--"the task"--and the conceptualization and deployment of "learning…

Study of efficacy of esthetic High-Intensity Focused Ultrasound system on Iranian skin for reducing the laxity and wrinkles of aging.

PubMed

Saket, Parvaneh; Shobeihi, Shobeir; Mehrdadi, Soroush

2017-09-01

Ultrasound is a mechanical wave that transmitted in a straight line and it can be focused at frequencies of 1-7 MHz with a high degree of precision. An important aspect of HIFU is that damaging focal point is located several millimeters below the surface of the skin and tissue above and below the focal point remains unaffected. Due to absorption of this energy, temperature of tissue rises to more than 60°C and this stimulates the cells for collagen production and tissue rejuvenation. To evaluate the clinical efficacy and safety of High-Intensity Focused Ultrasound on Skin Laxity and wrinkles. The study involved 22 women aged 35-62 with skin type II-IV. HIFU device with three transducers was employed. Various focal depths with different energies were used in accordance with skin thickness. Improvement for seven regions of face and whole face were evaluated by two dermatologists and patients 3 months after treatment. All of the patients completed the study. Three months after treatment, there was a highly statistical improvement in skin laxity for all of the patients. Also, the average percentage of improvement by doctor's opinion and patients was 58% and 60%, respectively. The experimental data obtained from dermatologists and patients showed that HIFU appears to be a safe and effective modality for skin laxity treatment. © 2017 Wiley Periodicals, Inc.

Effects of laser acupoint irradiation on energy metabolism of brain tissue of rats with cerebral ischemia-reperfusion

NASA Astrophysics Data System (ADS)

Xiong, Guoxin; Li, Xinzhong

2017-12-01

The protective effect and mechanism of low-intensity laser acupoint irradiation on focal cerebral ischemia-reperfusion (CIR) injury in rats were investigated. Male Sprague-Dawley rats were randomly divided into a sham group, a CIR model (model) group, and a model plus laser irradiation (laser) group. The focal CIR model was induced by middle cerebral artery occlusion in all except the rats in the sham group. After modeling, the Baihui, Mingmen, and left Zusanli points of the rats in the laser group were irradiated with 15 mW using a semiconductor laser, and each point was irradiated for 15 min once a day for 7 d. The treatments used in the sham and model groups were the same as in the laser group except that the laser output power was zero. After treatment, the expressions of serum superoxide dismutase (SOD) activity and serum malonaldehyde (MDA) content, the expression of growth-associated protein (GAP-43), the activities of succinic dehydrogenase and lactic dehydrogenase in brain tissue, were measured. The results showed that acupoint irradiation with a semiconductor laser can improve energy metabolism, enhance the expression of GAP-43, increase the levels of expression of serum SOD, and decrease the serum MDA content in a rat model of focal CIR, suggesting the mechanism for reduction of CIR injury.

Dual light-emitting diode-based multichannel microscopy for whole-slide multiplane, multispectral and phase imaging.

PubMed

Liao, Jun; Wang, Zhe; Zhang, Zibang; Bian, Zichao; Guo, Kaikai; Nambiar, Aparna; Jiang, Yutong; Jiang, Shaowei; Zhong, Jingang; Choma, Michael; Zheng, Guoan

2018-02-01

We report the development of a multichannel microscopy for whole-slide multiplane, multispectral and phase imaging. We use trinocular heads to split the beam path into 6 independent channels and employ a camera array for parallel data acquisition, achieving a maximum data throughput of approximately 1 gigapixel per second. To perform single-frame rapid autofocusing, we place 2 near-infrared light-emitting diodes (LEDs) at the back focal plane of the condenser lens to illuminate the sample from 2 different incident angles. A hot mirror is used to direct the near-infrared light to an autofocusing camera. For multiplane whole-slide imaging (WSI), we acquire 6 different focal planes of a thick specimen simultaneously. For multispectral WSI, we relay the 6 independent image planes to the same focal position and simultaneously acquire information at 6 spectral bands. For whole-slide phase imaging, we acquire images at 3 focal positions simultaneously and use the transport-of-intensity equation to recover the phase information. We also provide an open-source design to further increase the number of channels from 6 to 15. The reported platform provides a simple solution for multiplexed fluorescence imaging and multimodal WSI. Acquiring an instant focal stack without z-scanning may also enable fast 3-dimensional dynamic tracking of various biological samples. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Exploiting Satellite Focal Plane Geometry for Automatic Extraction of Traffic Flow from Single Optical Satellite Imagery

NASA Astrophysics Data System (ADS)

Krauß, T.

2014-11-01

The focal plane assembly of most pushbroom scanner satellites is built up in a way that different multispectral or multispectral and panchromatic bands are not all acquired exactly at the same time. This effect is due to offsets of some millimeters of the CCD-lines in the focal plane. Exploiting this special configuration allows the detection of objects moving during this small time span. In this paper we present a method for automatic detection and extraction of moving objects - mainly traffic - from single very high resolution optical satellite imagery of different sensors. The sensors investigated are WorldView-2, RapidEye, Pléiades and also the new SkyBox satellites. Different sensors require different approaches for detecting moving objects. Since the objects are mapped on different positions only in different spectral bands also the change of spectral properties have to be taken into account. In case the main distance in the focal plane is between the multispectral and the panchromatic CCD-line like for Pléiades an approach for weighted integration to receive mostly identical images is investigated. Other approaches for RapidEye and WorldView-2 are also shown. From these intermediate bands difference images are calculated and a method for detecting the moving objects from these difference images is proposed. Based on these presented methods images from different sensors are processed and the results are assessed for detection quality - how many moving objects can be detected, how many are missed - and accuracy - how accurate is the derived speed and size of the objects. Finally the results are discussed and an outlook for possible improvements towards operational processing is presented.

Probabilistic joint inversion of waveforms and polarity data for double-couple focal mechanisms of local earthquakes

NASA Astrophysics Data System (ADS)

Wéber, Zoltán

2018-06-01

Estimating the mechanisms of small (M < 4) earthquakes is quite challenging. A common scenario is that neither the available polarity data alone nor the well predictable near-station seismograms alone are sufficient to obtain reliable focal mechanism solutions for weak events. To handle this situation we introduce here a new method that jointly inverts waveforms and polarity data following a probabilistic approach. The procedure called joint waveform and polarity (JOWAPO) inversion maps the posterior probability density of the model parameters and estimates the maximum likelihood double-couple mechanism, the optimal source depth and the scalar seismic moment of the investigated event. The uncertainties of the solution are described by confidence regions. We have validated the method on two earthquakes for which well-determined focal mechanisms are available. The validation tests show that including waveforms in the inversion considerably reduces the uncertainties of the usually poorly constrained polarity solutions. The JOWAPO method performs best when it applies waveforms from at least two seismic stations. If the number of the polarity data is large enough, even single-station JOWAPO inversion can produce usable solutions. When only a few polarities are available, however, single-station inversion may result in biased mechanisms. In this case some caution must be taken when interpreting the results. We have successfully applied the JOWAPO method to an earthquake in North Hungary, whose mechanism could not be estimated by long-period waveform inversion. Using 17 P-wave polarities and waveforms at two nearby stations, the JOWAPO method produced a well-constrained focal mechanism. The solution is very similar to those obtained previously for four other events that occurred in the same earthquake sequence. The analysed event has a strike-slip mechanism with a P axis oriented approximately along an NE-SW direction.

The Teaching of Global Environmental Problems According to the Constructivist Approach: As a Focal Point of the Problem and the Availability of Concept Cartoons

ERIC Educational Resources Information Center

Oluk, Sami; Ozalp, Isilay

2007-01-01

In this study, with selecting the focusing point of the problem as the availability of cartoons, the teaching of global environmental problems according to the constructivist theory is investigated on the 7th graders in rural areas. This study is restricted with the global warming (G), ozone depletion (O) and the acid rain (A) problems. In the…

Single- and two-color infrared focal plane arrays made by MBE in HgCdTe

NASA Astrophysics Data System (ADS)

Zanatta, Jean-Paul; Ferret, P.; Loyer, R.; Petroz, G.; Cremer, S.; Chamonal, Jean-Paul; Bouchut, Philippe; Million, Alain; Destefanis, Gerard L.

2000-12-01

We present here recent developments obtained at LETI infrared laboratory in the field of infrared detectors made in HgCdTe material and using the molecular beam epitaxial growth technique (MBE). We discuss the metallurgical points (growth temperature and flux control) that lead to achieve excellent quality epitaxial layers grown by MBE. We show a run-to-run reproducibility measured on growth run of more than 15 layers. The crystalline quality, surface morphology, and composition uniformity are excellent. The etch pits density (EPD) are in the low 105.cm-2 when HgCdTe grows on a CdZnTe substrate. Transport properties reveal a low n-type carrier concentration in the 1014 to 1015.cm-3 range with a carrier mobility in excess of 105 cm2/V/sec at 77K for epilayers grown with 10 micrometers cutoff wavelength. We describe the performances of several kinds of our HgCdTe- MBE devices: single color MWIR and LWIR detectors on HgCdTe/CdZnTe operating at 77K in respectively (3-5 micrometers ) and (8-12 micrometers ) wavelength range; single color MWIR detectors on HgCdTe grown on germanium heterosubstrate operating at 77K in the (3-5 micrometers ) wavelength range; two color HgCdTe detectors operating within the MWIR (3-5 micrometers ) band.

Fabrication and Characterization of Single-Aperture 3.5-MHz BNT-Based Ultrasonic Transducer for Therapeutic Application.

PubMed

Taghaddos, Elaheh; Ma, T; Zhong, Hui; Zhou, Qifa; Wan, M X; Safari, Ahmad

2018-04-01

This paper discusses the fabrication and characterization of 3.5-MHz single-element transducers for therapeutic applications in which the active elements are made of hard lead-free BNT-based and hard commercial PZT (PZT-841) piezoceramics. Composition of (BiNa 0.88 K 0.08 Li 0.04 ) 0.5 (Ti 0.985 Mn 0.015 )O 3 (BNKLT88-1.5Mn) was used to develop lead-free piezoelectric ceramic. Mn-doped samples exhibited high mechanical quality factor ( ) of 970, thickness coupling coefficient ( ) of 0.48, a dielectric constant ( ) of 310 (at 1 kHz), depolarization temperature ( ) of 200 °C, and coercive field ( ) of 52.5 kV/cm. Two different unfocused single-element transducers using BNKLT88-1.5Mn and PZT-841 with the same center frequency of 3.5 MHz and similar aperture size of 10.7 and 10.5 mm were fabricated. Pulse-echo response, acoustic frequency spectrum, acoustic pressure field, and acoustic intensity field of transducers were characterized. The BNT-based transducer shows linear response up to the peak-to-peak voltage of 105 V in which the maximum rarefactional acoustic pressure of 1.1 MPa, and acoustic intensity of 43 W/cm 2 were achieved. Natural focal point of this transducer was at 60 mm from the surface of the transducer.

Recreation of three-dimensional objects in a real-time simulated environment by means of a panoramic single lens stereoscopic image-capturing device

NASA Astrophysics Data System (ADS)

Wong, Erwin

2000-03-01

Traditional methods of linear based imaging limits the viewer to a single fixed-point perspective. By means of a single lens multiple perspective mirror system, a 360-degree representation of the area around the camera is reconstructed. This reconstruction is used overcome the limitations of a traditional camera by providing the viewer with many different perspectives. By constructing the mirror into a hemispherical surface with multiple focal lengths at various diameters on the mirror, and by placing a parabolic mirror overhead, a stereoscopic image can be extracted from the image captured by a high-resolution camera placed beneath the mirror. Image extraction and correction is made by computer processing of the image obtained by camera; the image present up to five distinguishable different viewpoints that a computer can extrapolate pseudo- perspective data from. Geometric and depth for field can be extrapolated via comparison and isolation of objects within a virtual scene post processed by the computer. Combining data with scene rendering software provides the viewer with the ability to choose a desired viewing position, multiple dynamic perspectives, and virtually constructed perspectives based on minimal existing data. An examination into the workings of the mirror relay system is provided, including possible image extrapolation and correctional methods. Generation of data and virtual interpolated and constructed data is also mentioned.

Performance and cost benefits associated with nonimaging secondary concentrators used in point-focus dish solar thermal applications

NASA Astrophysics Data System (ADS)

Ogallagher, J.; Winston, R.

1987-09-01

Using nonimaging secondary concentrators in point-focus applications may permit the development of more cost-effective concentrator systems by either improving performance or reducing costs. Secondaries may also increase design flexibility. The major objective of this study was to develop as complete an understanding as possible of the quantitative performance and cost effects associated with deploying nonimaging secondary concentrators at the focal zone of point-focus solar thermal concentrators. A performance model was developed that uses a Monte Carlo ray-trace procedure to determine the focal plane distribution of a paraboloidal primary as a function of optical parameters. It then calculates the corresponding optimized concentration and thermal efficiency as a function of temperature with and without the secondary. To examine the potential cost benefits associated with secondaries, a preliminary model for the rational optimization of performance versus cost trade-offs was developed. This model suggests a possible 10 to 20 percent reduction in the cost of delivered energy when secondaries are used. This is a lower limit, and the benefits may even be greater if using a secondary permits the development of inexpensive primary technologies for which the performance would not otherwise be viable.

Development and Beam-Shape Analysis of an Integrated Fiber-Optic Confocal Probe for High-Precision Central Thickness Measurement of Small-Radius Lenses

PubMed Central

Sutapun, Boonsong; Somboonkaew, Armote; Amarit, Ratthasart; Chanhorm, Sataporn

2015-01-01

This work describes a new design of a fiber-optic confocal probe suitable for measuring the central thicknesses of small-radius optical lenses or similar objects. The proposed confocal probe utilizes an integrated camera that functions as a shape-encoded position-sensing device. The confocal signal for thickness measurement and beam-shape data for off-axis measurement can be simultaneously acquired using the proposed probe. Placing the probe’s focal point off-center relative to a sample’s vertex produces a non-circular image at the camera’s image plane that closely resembles an ellipse for small displacements. We were able to precisely position the confocal probe’s focal point relative to the vertex point of a ball lens with a radius of 2.5 mm, with a lateral resolution of 1.2 µm. The reflected beam shape based on partial blocking by an aperture was analyzed and verified experimentally. The proposed confocal probe offers a low-cost, high-precision technique, an alternative to a high-cost three-dimensional surface profiler, for tight quality control of small optical lenses during the manufacturing process. PMID:25871720

Laser machining-- a status report

Treesearch

C. W. McMillin

1972-01-01

The laser (an acronym for Light Amplification by Stimulated Emission of Radiation) provides a source of intense optical radiation. This energy can be focused to a very small diameter. At even moderate power levels, therefore, the energy at the focal point is sufficient to vaporize most materials.

Meet the Alpha-Pets.

ERIC Educational Resources Information Center

Zitlaw, Jo Ann Bruce; Frank, Cheryl Standish

1985-01-01

"Alpha-Pets" are the focal point of an integrated, multidisciplinary curriculum. Each pet is featured for a week in a vocabulary-rich story and introduces related activities beginning with the featured letter, such as the four food groups during Freddie Fish's week or universe during Ulysses Unicorn's week. (MT)

Compact range for variable-zone measurements

DOEpatents

Burnside, Walter D.; Rudduck, Roger C.; Yu, Jiunn S.

1988-08-02

A compact range for testing antennas or radar targets includes a source for directing energy along a feedline toward a parabolic reflector. The reflected wave is a spherical wave with a radius dependent on the distance of the source from the focal point of the reflector.

76 FR 21908 - Statement of Organization, Functions, and Delegations of Authority

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-19

... areas of traditional and new media, including Web initiatives such as social media supported by innovative, increasingly mobile technologies; media relations; public information campaigns; and speechwriting. Serves as CMS' focal point in all activities related to the media. Provides consultation, advice...

32 CFR 85.6 - Procedures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... serve as the focal point for all health promotion program issues and to integrate the activities of the... prevention and cessation, physical fitness, nutrition, stress management, alcohol and drug abuse, and early.... (v) As part of routine physical and dental examinations and at other appropriate times, health care...

Compact range for variable-zone measurements

DOEpatents

Burnside, Walter D.; Rudduck, Roger C.; Yu, Jiunn S.

1988-01-01

A compact range for testing antennas or radar targets includes a source for directing energy along a feedline toward a parabolic reflector. The reflected wave is a spherical wave with a radius dependent on the distance of the source from the focal point of the reflector.

In Defense of the Vendors

ERIC Educational Resources Information Center

Irwin, G. Brockett

1975-01-01

The problems that are encountered when cooperation breaks down between the industrial source operator and the pollution control equipment vendor are examined. The focal point of this examination is the study of defenses available to the equipment vendor when industrial source operators refuse to cooperate. (Author/BT)

76 FR 19376 - Statement of Organizations, Functions, and Delegations of Authority

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-07

... safety mission. These outside groups include academic organizations, private organizations, and other Federal Agencies. 3. Coordinates the access to large databases for pharmacoepidemiologic and..., procedures, training, and security or databases available to OSE. 3. Acts as focal point for all hardware...

Stress analysis of the space telescope focal plane structure joint

NASA Technical Reports Server (NTRS)

Foster, W. A., Jr.; Shoemaker, W. L.

1985-01-01

Two major efforts were begun concerning the Space Telescope focal plane structure joint. The 3-D solid finite element modeling of the bipod flexure plate was carried out. Conceptual models were developed for the load transfer through the three major bolts to the flexure plate. The flexure plate drawings were reconstructed using DADAM for the purpose of developing a file from which the coordinates of any point on the flexure plate could be determined and also to locate the attachment points of the various components which connect with the flexure plate. For modeling convenience the CADAM drawing of the flexure plate has been divided into several regions which will be subdivided into finite elements using MSGMESH, which is a finite element mesh generator available with MSC/NASTRAN. In addition to the CADAM work on the flexure plate, an effort was also begun to develop computer aided drawings of the peripheral beam which will be used to assist in modeling the connection between it and the flexure plate.

Applications of two-photon fluorescence microscopy in deep-tissue imaging

NASA Astrophysics Data System (ADS)

Dong, Chen-Yuan; Yu, Betty; Hsu, Lily L.; Kaplan, Peter D.; Blankschstein, D.; Langer, Robert; So, Peter T. C.

2000-07-01

Based on the non-linear excitation of fluorescence molecules, two-photon fluorescence microscopy has become a significant new tool for biological imaging. The point-like excitation characteristic of this technique enhances image quality by the virtual elimination of off-focal fluorescence. Furthermore, sample photodamage is greatly reduced because fluorescence excitation is limited to the focal region. For deep tissue imaging, two-photon microscopy has the additional benefit in the greatly improved imaging depth penetration. Since the near- infrared laser sources used in two-photon microscopy scatter less than their UV/glue-green counterparts, in-depth imaging of highly scattering specimen can be greatly improved. In this work, we will present data characterizing both the imaging characteristics (point-spread-functions) and tissue samples (skin) images using this novel technology. In particular, we will demonstrate how blind deconvolution can be used further improve two-photon image quality and how this technique can be used to study mechanisms of chemically-enhanced, transdermal drug delivery.

Influence of Radiographic Positioning on Canine Sacroiliac and Lumbosacral Angle Measurements.

PubMed

Jones, Susan; Savage, Mason; Naughton, Brian; Singh, Susheela; Robertson, Ian; Roe, Simon C; Marcellin-Little, Denis J; Mathews, Kyle G

2018-01-01

 To evaluate the influence of radiographic malpositioning on canine sacroiliac and lumbosacral inclination angles.  Using canine cadavers, lateral pelvic radiographs were acquired with the radiographic beam in a neutral position and then rotated 5, 10 and 15° to mimic rotational malpositioning. The focal point of the beam was then focused over the abdomen and again over mid-diaphysis of the femur to mimic an abdominal or femoral radiographic study.  Five degrees of rotational malpositioning did not influence measurements of sacroiliac or lumbosacral inclination, but malpositioning by more than 5° led to a significant decrease in both sacroiliac and lumbosacral angles. Moving the focal point to the femur significantly decreased the measured lumbosacral angle. Abdominally centred radiographs had no effect on lumbosacral and sacroiliac angle measurements.  When evaluating canine lumbosacral and sacroiliac angles radiographically, pelvic rotation of more than 5° should be avoided as should the use of lateral radiographs centred over the femur. Schattauer GmbH Stuttgart.

IAL SPACE: A test laboratory for the ISO cryogenic payload

NASA Technical Reports Server (NTRS)

Cucchiaro, A.; Henrist, M.; Macau, J. P.; Ninane, N.; Blanpain, R.

1990-01-01

The ESA Infrared Space Observatory (ISO) satellite is a 3 axes pointed platform designed to make accurate pointed observations of astronomical objects and sources in the wavelength range between 2.5 and 200 microns. ISO is composed of a service module and a payload module which is a large cylindrical vacuum vessel. The vessel is in fact a cryostat (capacity of 2250 l of liquid He II) which contains the telescope and the four focal scientific instruments. The latter being cooled up to a temperature less than 4 K. The qualification of the payload requires the measurement respectively of: the image quality of the telescope through wave front error (WFE) measurements; and the optical alignment of the scientific instruments with respect to the telescope axis and the telescope focus, and this under cryogenic conditions. Consequently, since 1988, the FOCAL 5 IAL Space facility has been upgraded in order to perform the cryogenic optical tests of the ISO optical subsystems.

Status of national diabetes programmes in the Americas.

PubMed Central

White, F.; Nanan, D.

1999-01-01

Reported are the responses in the latter half of 1997 of all ministries of health in the Region of the Americas to the Declaration of the Americas on Diabetes, which was adopted by the Directing Council of the Pan American Health Organization (PAHO) in 1996 as a basis for national programme development in diabetes. The short-term targets were the designation of national focal points, the preparation of national estimates of the disease burden, and the development and implementation of national strategies and plans to deal with diabetes. The survey found that most countries recognized diabetes as a significant public health problem. In terms of global relevance, a number of lessons have been learned from this exercise: the role of broadly based participation in gaining recognition at the national health policy level; the wide acceptance of an integrated programme model; the relevance of process-related targets to achieve short-term success; and the critical role of having a designated focal point within the managerial approach. PMID:10680245

Precision Control Module For UV Laser 3D Micromachining

NASA Astrophysics Data System (ADS)

Wu, Wen-Hong; Hung, Min-Wei; Chang, Chun-Li

2011-01-01

UV laser has been widely used in various micromachining such as micro-scribing or patterning processing. At present, most of the semiconductors, LEDs, photovoltaic solar panels and touch panels industries need the UV laser processing system. However, most of the UV laser processing applications in the industries utilize two dimensional (2D) plane processing. And there are tremendous business opportunities that can be developed, such as three dimensional (3D) structures of micro-electromechanical (MEMS) sensor or the precision depth control of indium tin oxide (ITO) thin films edge insulation in touch panels. This research aims to develop a UV laser 3D micromachining module that can create the novel applications for industries. By special designed beam expender in optical system, the focal point of UV laser can be adjusted quickly and accurately through the optical path control lens of laser beam expender optical system. Furthermore, the integrated software for galvanometric scanner and focal point adjustment mechanism is developed as well, so as to carry out the precise 3D microstructure machining.

Novel imaging closed loop control strategy for heliostats

NASA Astrophysics Data System (ADS)

Bern, Gregor; Schöttl, Peter; Heimsath, Anna; Nitz, Peter

2017-06-01

Central Receiver Systems use up to thousands of heliostats to concentrate solar radiation. The precise control of heliostat aiming points is crucial not only for efficiency but also for reliable plant operation. Besides the calibration of open loop control systems, closed loop tracking strategies are developed to address a precise and efficient aiming strategy. The need for cost reductions in the heliostat field intensifies the motivation for economic closed loop control systems. This work introduces an approach for a closed loop heliostat tracking strategy using image analysis and signal modulation. The approach aims at the extraction of heliostat focal spot position within the receiver domain by means of a centralized remote vision system decoupled from the rough conditions close to the focal area. Taking an image sequence of the receiver while modulating a signal on different heliostats, their aiming points are retrieved. The work describes the methodology and shows first results from simulations and practical tests performed in small scale, motivating further investigation and deployment.

Scanning transmission electron microscopy through-focal tilt-series on biological specimens.

PubMed

Trepout, Sylvain; Messaoudi, Cédric; Perrot, Sylvie; Bastin, Philippe; Marco, Sergio

2015-10-01

Since scanning transmission electron microscopy can produce high signal-to-noise ratio bright-field images of thick (≥500 nm) specimens, this tool is emerging as the method of choice to study thick biological samples via tomographic approaches. However, in a convergent-beam configuration, the depth of field is limited because only a thin portion of the specimen (from a few nanometres to tens of nanometres depending on the convergence angle) can be imaged in focus. A method known as through-focal imaging enables recovery of the full depth of information by combining images acquired at different levels of focus. In this work, we compare tomographic reconstruction with the through-focal tilt-series approach (a multifocal series of images per tilt angle) with reconstruction with the classic tilt-series acquisition scheme (one single-focus image per tilt angle). We visualised the base of the flagellum in the protist Trypanosoma brucei via an acquisition and image-processing method tailored to obtain quantitative and qualitative descriptors of reconstruction volumes. Reconstructions using through-focal imaging contained more contrast and more details for thick (≥500 nm) biological samples. Copyright © 2015 Elsevier Ltd. All rights reserved.

Focal myositis: A review.

PubMed

Devic, P; Gallay, L; Streichenberger, N; Petiot, P

2016-11-01

Amongst the heterogeneous group of inflammatory myopathies, focal myositis stands as a rare and benign dysimmune disease. Although it can be associated with root and/or nerve lesions, traumatic muscle lesions and autoimmune diseases, its triggering factors remain poorly understood. Defined as an isolated inflammatory pseudotumour usually restricted to one skeletal muscle, clinical presentation of focal myositis is that of a rapidly growing solitary mass within a single muscle, usually in the lower limbs. Electromyography shows spontaneous activity associated with a myopathic pattern. MRI reveals a contrast enhanced enlarged muscle appearing hyper-intense on FAT-SAT T2 weighted images. Adjacent structures are spared and there are no calcifications. Serum creatine kinase (CK) levels are usually moderately augmented and biological markers of systemic inflammation are absent in most cases. Pathological histological features include marked variation in fibre size, inflammatory infiltrates mostly composed of T CD4+ lymphocytes and macrophages, degenerating/regenerating fibres and interstitial fibrosis. Differential diagnoses are numerous and include myositis of other origin with focal onset. Steroid treatment should be reserved for patients who present with major pain, nerve lesions, associated autoimmune disease, or elevated C reactive protein or CK. Copyright © 2016 Elsevier B.V. All rights reserved.

Fine Guidance Sensing for Coronagraphic Observatories

NASA Technical Reports Server (NTRS)

Brugarolas, Paul; Alexander, James W.; Trauger, John T.; Moody, Dwight C.

2011-01-01

Three options have been developed for Fine Guidance Sensing (FGS) for coronagraphic observatories using a Fine Guidance Camera within a coronagraphic instrument. Coronagraphic observatories require very fine precision pointing in order to image faint objects at very small distances from a target star. The Fine Guidance Camera measures the direction to the target star. The first option, referred to as Spot, was to collect all of the light reflected from a coronagraph occulter onto a focal plane, producing an Airy-type point spread function (PSF). This would allow almost all of the starlight from the central star to be used for centroiding. The second approach, referred to as Punctured Disk, collects the light that bypasses a central obscuration, producing a PSF with a punctured central disk. The final approach, referred to as Lyot, collects light after passing through the occulter at the Lyot stop. The study includes generation of representative images for each option by the science team, followed by an engineering evaluation of a centroiding or a photometric algorithm for each option. After the alignment of the coronagraph to the fine guidance system, a "nulling" point on the FGS focal point is determined by calibration. This alignment is implemented by a fine alignment mechanism that is part of the fine guidance camera selection mirror. If the star images meet the modeling assumptions, and the star "centroid" can be driven to that nulling point, the contrast for the coronagraph will be maximized.

Stellar figure sensor

NASA Technical Reports Server (NTRS)

Peters, W. N.

1973-01-01

A compilation of analytical and experimental data is presented concerning the stellar figure sensor. The sensor is an interferometric device which is located in the focal plane of an orbiting large space telescope (LST). The device was designed to perform interferometry on the optical wavefront of a single star after it has propagated through the LST. An analytical model of the device was developed and its accuracy was verified by an operating laboratory breadboard. A series of linear independent control equations were derived which define the operations required for utilizing a focal plane figure sensor in the control loop for the secondary mirror position and for active control of the primary mirror.

Humanoid monocular stereo measuring system with two degrees of freedom using bionic optical imaging system

NASA Astrophysics Data System (ADS)

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

2017-10-01

Based on the process by which the spatial depth clue is obtained by a single eye, a monocular stereo vision to measure the depth information of spatial objects was proposed in this paper and a humanoid monocular stereo measuring system with two degrees of freedom was demonstrated. The proposed system can effectively obtain the three-dimensional (3-D) structure of spatial objects of different distances without changing the position of the system and has the advantages of being exquisite, smart, and flexible. The bionic optical imaging system we proposed in a previous paper, named ZJU SY-I, was employed and its vision characteristic was just like the resolution decay of the eye's vision from center to periphery. We simplified the eye's rotation in the eye socket and the coordinated rotation of other organs of the body into two rotations in the orthogonal direction and employed a rotating platform with two rotation degrees of freedom to drive ZJU SY-I. The structure of the proposed system was described in detail. The depth of a single feature point on the spatial object was deduced, as well as its spatial coordination. With the focal length adjustment of ZJU SY-I and the rotation control of the rotation platform, the spatial coordinates of all feature points on the spatial object could be obtained and then the 3-D structure of the spatial object could be reconstructed. The 3-D structure measurement experiments of two spatial objects with different distances and sizes were conducted. Some main factors affecting the measurement accuracy of the proposed system were analyzed and discussed.

Control of treatment size in cavitation-enhanced high-intensity focused ultrasound using radio-frequency echo signals

NASA Astrophysics Data System (ADS)

Tomiyasu, Kentaro; Takagi, Ryo; Iwasaki, Ryosuke; Yoshizawa, Shin; Umemura, Shin-ichiro

2017-07-01

In high-intensity focused ultrasound (HIFU) treatment, controlling the ultrasound dose at each focal target spot is important because it is a problem that the length of the coagulated region in front of the focal point deviates owing to the differences in absorption in each focal target spot and attenuation in the intervening tissues. In this study, the detected changes in the power spectra of HIFU echoes were used by controlling the HIFU duration in the “trigger HIFU” sequence with the aim to increase coagulation size through the enhancement of the ultrasonic heating by the cavitation induced by the preceding extremely high intensity short “trigger” pulse. The result shows that this method can be used to detect boiling bubbles and the following generated cavitation bubbles at their early stage. By automatically stopping HIFU exposure immediately after detecting the bubbles, overheating was prevented and the deviation of the length of the coagulated region was reduced.

Big capabilities in small packages: hyperspectral imaging from a compact platform

NASA Astrophysics Data System (ADS)

Beasley, Matthew; Goldberg, Hannah; Voorhees, Christopher; Illsley, Peter

2016-09-01

We present the Compact Holographic Aberration-corrected Platform (CHAP) instrument, designed and developed at Planetary Resources Development Corporation. By combining a dispersive element with the secondary of a telescope, we are able to produce a relatively long focal length with moderate dispersion at the focal plane. This design enables us to build a capable hyperspectral imaging instrument within the size constraints of the Cubesat form-factor. The advantages of our design revolves around its simplicity: there are only two optical elements, producing both a white light and diffracted image. With the use of a replicated grating, we can produce a long focal length hyperspectral imager at a price point far below other spaceflight instruments. The design is scalable for larger platforms and since it has no transmitting optics and only two reflective surfaces could be designed to function at any desired wavelength. Our system will be capable of spectral imaging across the 400 to 900 nm spectral range for use in small body surveys.

Nonlinear Focal Modulation Microscopy.

PubMed

Zhao, Guangyuan; Zheng, Cheng; Kuang, Cuifang; Zhou, Renjie; Kabir, Mohammad M; Toussaint, Kimani C; Wang, Wensheng; Xu, Liang; Li, Haifeng; Xiu, Peng; Liu, Xu

2018-05-11

We demonstrate nonlinear focal modulation microscopy (NFOMM) to achieve superresolution imaging. Traditional approaches to superresolution that utilize point scanning often rely on spatially reducing the size of the emission pattern by directly narrowing (e.g., through minimizing the detection pinhole in Airyscan, Zeiss) or indirectly peeling its outer profiles [e.g., through depleting the outer emission region in stimulated emission depletion (STED) microscopy]. We show that an alternative conceptualization that focuses on maximizing the optical system's frequency shifting ability offers advantages in further improving resolution while reducing system complexity. In NFOMM, a spatial light modulator and a suitably intense laser illumination are used to implement nonlinear focal-field modulation to achieve a transverse spatial resolution of ∼60  nm (∼λ/10). We show that NFOMM is comparable with STED microscopy and suitable for fundamental biology studies, as evidenced in imaging nuclear pore complexes, tubulin and vimentin in Vero cells. Since NFOMM is readily implemented as an add-on module to a laser-scanning microscope, we anticipate wide utility of this new imaging technique.

Effect of the focal plane position on CO2 laser beam cutting of injection molded polycarbonate sheets

NASA Astrophysics Data System (ADS)

Moradi, Mahmoud; Mehrabi, Omid; Azdast, Taher; Benyounis, Khaled Y.

2016-11-01

In the present research, the effect of laser beam focal plane position (FPP) on the kerf quality of the polycarbonate laser cutting is investigated. Low power CO2 laser is used as the heat source of the cutting runs. In the experiments, FPP is varied from 0 to -4mm while other processing parameters (i.e. laser power, cutting speed and gas pressure) are considered constant. Upper and lower kerf width, kerf taper, upper heat affected zone and surface roughness of the kerf wall are also considered as the responses. Observations signified that reducing the position of the laser beam focal point from zero to - 3mm reduces the upper and lower kerf width. However reducing FPP below -3mm leads to an increase in the kerf width. Results also reveals that upper heat affected zone value reduces by reduction in FPP. Moreover the best kerf wall surface roughness occurred at FPP= -3mm.

Efficacy and tolerability of oral lacosamide as adjunctive therapy in pediatric patients with pharmacoresistant focal epilepsy.

PubMed

Gavatha, M; Ioannou, I; Papavasiliou, A S

2011-04-01

The results of adjunctive lacosamide treatment in 18 pediatric patients with pharmacoresistant focal epilepsy are reported. All had severe forms of focal epilepsy with or without secondary generalization and were concurrently receiving one to three other antiepileptic drugs. Lacosamide was administered orally, and final dose, after slow titration, ranged between 1.7 and 10 mg/kg. Mean treatment duration was 8 months (range=3 weeks-17 months). Treatment efficacy was assessed at two time points with a 1-year interval. The reported greater than 50% reduction in seizure frequency was 36% in the initial short-term and 20% in the following long-term assessment. Side effects, mostly somnolence and irritability, were reported by 39% of patients in both evaluations. Our data suggest that lacosamide treatment in pediatric patients is safe at doses up to 10 mg/kg/day without any major side effects, but studies in larger series are needed to validate and extend these findings. Copyright © 2011 Elsevier Inc. All rights reserved.

Nonlinear Focal Modulation Microscopy

NASA Astrophysics Data System (ADS)

Zhao, Guangyuan; Zheng, Cheng; Kuang, Cuifang; Zhou, Renjie; Kabir, Mohammad M.; Toussaint, Kimani C.; Wang, Wensheng; Xu, Liang; Li, Haifeng; Xiu, Peng; Liu, Xu

2018-05-01

We demonstrate nonlinear focal modulation microscopy (NFOMM) to achieve superresolution imaging. Traditional approaches to superresolution that utilize point scanning often rely on spatially reducing the size of the emission pattern by directly narrowing (e.g., through minimizing the detection pinhole in Airyscan, Zeiss) or indirectly peeling its outer profiles [e.g., through depleting the outer emission region in stimulated emission depletion (STED) microscopy]. We show that an alternative conceptualization that focuses on maximizing the optical system's frequency shifting ability offers advantages in further improving resolution while reducing system complexity. In NFOMM, a spatial light modulator and a suitably intense laser illumination are used to implement nonlinear focal-field modulation to achieve a transverse spatial resolution of ˜60 nm (˜λ /10 ). We show that NFOMM is comparable with STED microscopy and suitable for fundamental biology studies, as evidenced in imaging nuclear pore complexes, tubulin and vimentin in Vero cells. Since NFOMM is readily implemented as an add-on module to a laser-scanning microscope, we anticipate wide utility of this new imaging technique.

Ultrasound elastographic techniques in focal liver lesions

PubMed Central

Conti, Clara Benedetta; Cavalcoli, Federica; Fraquelli, Mirella; Conte, Dario; Massironi, Sara

2016-01-01

Elastographic techniques are new ultrasound-based imaging techniques developed to estimate tissue deformability/stiffness. Several ultrasound elastographic approaches have been developed, such as static elastography, transient elastography and acoustic radiation force imaging methods, which include point shear wave and shear wave imaging elastography. The application of these methods in clinical practice aims at estimating the mechanical tissues properties. One of the main settings for the application of these tools has been liver stiffness assessment in chronic liver disease, which has been studied mainly using transient elastography. Another field of application for these techniques is the assessment of focal lesions, detected by ultrasound in organs such as pancreas, prostate, breast, thyroid, lymph nodes. Considering the frequency and importance of the detection of focal liver lesions through routine ultrasound, some studies have also aimed to assess the role that elestography can play in studying the stiffness of different types of liver lesions, in order to predict their nature and thus offer valuable non-invasive methods for the diagnosis of liver masses. PMID:26973405

Ultrasound elastographic techniques in focal liver lesions.

PubMed

Conti, Clara Benedetta; Cavalcoli, Federica; Fraquelli, Mirella; Conte, Dario; Massironi, Sara

2016-03-07

Elastographic techniques are new ultrasound-based imaging techniques developed to estimate tissue deformability/stiffness. Several ultrasound elastographic approaches have been developed, such as static elastography, transient elastography and acoustic radiation force imaging methods, which include point shear wave and shear wave imaging elastography. The application of these methods in clinical practice aims at estimating the mechanical tissues properties. One of the main settings for the application of these tools has been liver stiffness assessment in chronic liver disease, which has been studied mainly using transient elastography. Another field of application for these techniques is the assessment of focal lesions, detected by ultrasound in organs such as pancreas, prostate, breast, thyroid, lymph nodes. Considering the frequency and importance of the detection of focal liver lesions through routine ultrasound, some studies have also aimed to assess the role that elestography can play in studying the stiffness of different types of liver lesions, in order to predict their nature and thus offer valuable non-invasive methods for the diagnosis of liver masses.

Mispronunciation Detection for Language Learning and Speech Recognition Adaptation

ERIC Educational Resources Information Center

Ge, Zhenhao

2013-01-01

The areas of "mispronunciation detection" (or "accent detection" more specifically) within the speech recognition community are receiving increased attention now. Two application areas, namely language learning and speech recognition adaptation, are largely driving this research interest and are the focal points of this work.…

Women's Handwork: Stories of Similarity and Diversity.

ERIC Educational Resources Information Center

Kellman, Julia

1996-01-01

Characterizes women's handwork (needlepoint, beadwork, embroidery, crocheting) as a valid means of artistic expression and an integral part of women's culture. Discusses the varieties of handwork and their relationships within local cultures. Recommends using these objects as focal points for studying art, local history, or social studies. (MJP)

Compact range for variable-zone measurements

DOEpatents

Burnside, W.D.; Rudduck, R.C.; Yu, J.S.

1987-02-27

A compact range for testing antennas or radar targets includes a source for directing energy along a feedline toward a parabolic reflector. The reflected wave is a spherical wave with a radius dependent on the distance of the source from the focal point of the reflector. 2 figs.

7 CFR 2.72 - Chairman, World Agricultural Outlook Board.

Code of Federal Regulations, 2014 CFR

2014-01-01

... climate. (i) Advise the Secretary on climate and weather activities, and coordinate the development of policy options on weather and climate. (ii) Coordinate all weather and climate information and monitoring activities within the Department and provide a focal point in the Department for weather and climate...

7 CFR 2.72 - Chairman, World Agricultural Outlook Board.

Code of Federal Regulations, 2011 CFR

2011-01-01

... climate. (i) Advise the Secretary on climate and weather activities, and coordinate the development of policy options on weather and climate. (ii) Coordinate all weather and climate information and monitoring activities within the Department and provide a focal point in the Department for weather and climate...

7 CFR 2.72 - Chairman, World Agricultural Outlook Board.

Code of Federal Regulations, 2012 CFR

2012-01-01

... climate. (i) Advise the Secretary on climate and weather activities, and coordinate the development of policy options on weather and climate. (ii) Coordinate all weather and climate information and monitoring activities within the Department and provide a focal point in the Department for weather and climate...

7 CFR 2.72 - Chairman, World Agricultural Outlook Board.

Code of Federal Regulations, 2013 CFR

2013-01-01

... climate. (i) Advise the Secretary on climate and weather activities, and coordinate the development of policy options on weather and climate. (ii) Coordinate all weather and climate information and monitoring activities within the Department and provide a focal point in the Department for weather and climate...

Ethics of the Health Educator as Behavior Change Agent in Gerontological Health.

ERIC Educational Resources Information Center

Neutens, James J.; Jackson, Michael L.

1985-01-01

As health education becomes a focal point in the health care system, more attention will be given to the professional practice of health educators. Understanding ethical theory and other value judgments will be an important aspect of the health education profession. (DF)

The Dispositions Improvement Process

ERIC Educational Resources Information Center

Brewer, Robin D.; Lindquist, Cynthia; Altemueller, Lisa

2011-01-01

Globally, teacher dispositions along with knowledge and skills continue to be the focal point of teacher education programs. Teachers influence children's development and therefore dispositions are a universal concern. For the past 20 years in the United States, teacher education programs have assessed dispositions. We, however, must now also use…

Monocrystalline CVD-diamond optics for high-power laser applications

NASA Astrophysics Data System (ADS)

Holly, C.; Traub, M.; Hoffmann, D.; Widmann, C.; Brink, D.; Nebel, C.; Gotthardt, T.; Sözbir, M. C.; Wenzel, C.

2016-03-01

The potential of diamond as an optical material for high-power laser applications in the wavelength regime from the visible spectrum (VIS) to the near infrared (NIR) is investigated. Single-crystal diamonds with lateral dimensions up to 7×7mm2 are grown with microwave plasma assisted chemical vapor deposition (MPACVD) in parallel with up to 60 substrates and are further processed to spherical optics for beam guidance and shaping. The synthetic diamonds offer superior thermal, mechanical and optical properties, including low birefringence, scattering and absorption, also around 1 μm wavelength. We present dielectric (AR and HR) coated single-crystal diamond optics which are tested under high laser power in the multi-kW regime. The thermally induced focal shift of the diamond substrates is compared to the focal shift of a standard collimating and focusing unit for laser cutting made of fused silica optics. Due to the high thermal conductivity and low absorption of the diamond substrates compared to the fused silica optics no additional focal shift caused by a thermally induced refractive index change in the diamond is observed in our experiments. We present experimental results regarding the performance of the diamond substrates with and without dielectric coatings under high power and the influences of growth induced birefringence on the optical quality. Finally, we discuss the potential of the presented diamond lenses for high-power applications in the field of laser materials processing.

Standardization in Performance Assessment of Telemetry Tracking Systems

DTIC Science & Technology

2013-09-01

for a defense system against ballistic missiles ( Kaplan , 2008). Back then the threat was realized by Germany’s V-2 rocket, the world’s first...Kennedy of Massachusetts ( Kaplan , 2008). “It is the policy of the United States to deploy as soon as is technologically possible an effective... P2 , and P3. The parabolic dish then reflects all this energy onto the focal point, point F. The feed of the antenna, which encloses or houses the

The Engineer Model Improvement Program Plan

DTIC Science & Technology

1988-08-01

evaluations of engineer doctrine placed it in a unique position to be a focal point for USACE modeling support. To this end, on 3 December of 1986 the CC...community in a 27 February 1980 memorandum in which the Army Chief of Staff urged the Chief of Engineers "... to relook the manner in which engineers...battlefield is controlled through a system of user-established Movement-Control- Points (MCPs). An MCP is described by X-Y-Z coordinates which define a

Simplified Architecture for Precise Aiming of a Deep-Space Communication Laser Transceiver

NASA Technical Reports Server (NTRS)

Ortiz, Gerard G.; Farr, William H.; Charles, Jeffrey R.

2011-01-01

The simplified architecture is a minimal system for a deep-space optical communications transceiver. For a deepspace optical communications link the simplest form of the transceiver requires (1) an efficient modulated optical source, (2) a point-ahead mechanism (PAM) to compensate for two-way light travel, (3) an aperture to reduce the divergence of the transmit laser communication signal and also to collect the uplink communication signal, and (4) a receive detector to sense the uplink communication signal. Additional components are introduced to mitigate for spacecraft microvibrations and to improve the pointing accuracy. The Canonical Transceiver implements this simplified architecture (see figure). A single photon-counting smart focal plane sensor combines acquisition, tracking, and forward link data detection functionality. This improves optical efficiency by eliminating channel splits. A transmit laser blind sensor (e.g. silicon with 1,550-nm beam) provides transmit beam-pointing feedback via the two-photon absorption (TPA) process. This vastly improves the transmit/receive isolation because only the focused transmit beam is detected. A piezoelectric tiptilt actuator implements the required point-ahead angle. This point-ahead mechanism has been demonstrated to have near zero quiescent power and is flight qualified. This architecture also uses an innovative 100-mHz resonant frequency passive isolation platform to filter spacecraft vibrations with voice coil actuators for active tip-tilt correction below the resonant frequency. The canonical deep-space optical communications transceiver makes synergistic use of innovative technologies to reduce size, weight, power, and cost. This optical transceiver can be used to retire risks associated with deep-space optical communications on a planetary pathfinder mission and is complementary to ongoing lunar and access link developments.

A Novel Closed-Head Model of Mild Traumatic Brain Injury Using Focal Primary Overpressure Blast to the Cranium in Mice

PubMed Central

Guley, Natalie H.; Rogers, Joshua T.; Del Mar, Nobel A.; Deng, Yunping; Islam, Rafiqul M.; D'Surney, Lauren; Ferrell, Jessica; Deng, Bowei; Hines-Beard, Jessica; Bu, Wei; Ren, Huiling; Elberger, Andrea J.; Marchetta, Jeffrey G.; Rex, Tonia S.; Honig, Marcia G.

2016-01-01

Abstract Mild traumatic brain injury (TBI) from focal head impact is the most common form of TBI in humans. Animal models, however, typically use direct impact to the exposed dura or skull, or blast to the entire head. We present a detailed characterization of a novel overpressure blast system to create focal closed-head mild TBI in mice. A high-pressure air pulse limited to a 7.5 mm diameter area on the left side of the head overlying the forebrain is delivered to anesthetized mice. The mouse eyes and ears are shielded, and its head and body are cushioned to minimize movement. This approach creates mild TBI by a pressure wave that acts on the brain, with minimal accompanying head acceleration-deceleration. A single 20-psi blast yields no functional deficits or brain injury, while a single 25–40 psi blast yields only slight motor deficits and brain damage. By contrast, a single 50–60 psi blast produces significant visual, motor, and neuropsychiatric impairments and axonal damage and microglial activation in major fiber tracts, but no contusive brain injury. This model thus reproduces the widespread axonal injury and functional impairments characteristic of closed-head mild TBI, without the complications of systemic or ocular blast effects or head acceleration that typically occur in other blast or impact models of closed-skull mild TBI. Accordingly, our model provides a simple way to examine the biomechanics, pathophysiology, and functional deficits that result from TBI and can serve as a reliable platform for testing therapies that reduce brain pathology and deficits. PMID:26414413

Shape analysis of cylindrical micromirrors for angular focusing

NASA Astrophysics Data System (ADS)

Hou, Max Ti-Kuang; Hong, Pei-Yuan; Chen, Rongshun

2001-11-01

In this paper, we analyze the shape of the cylindrical micromirror, which directly defines the profile of the reflecting surface, and is very important for the function on focusing. A cylindrical micromirror can converge incident rays to a real focal line after reflection, namely angular focusing. Therefore, under specific design two cylindrical micromirrors, the primary and secondary, can converge incident rays into a real focal point after twice reflection. The curved shape of micromirror, formed due to the stress-induced bending of the bilayer microstructure upon release, has been theoretically analyzed and numerically simulated. The results show that the reflecting surface, especially at boundaries, is not perfectly cylindrical, while adding longitudinal frames can make some improvement.

Line of Sight Stabilization of James Webb Space Telescope

NASA Technical Reports Server (NTRS)

Meza, Luis; Tung, Frank; Anandakrishnan, Satya; Spector, Victor; Hyde, Tupper

2005-01-01

The James Webb Space Telescope (JWST) builds upon the successful flight experience of the Chandra Xray Telescope by incorporating an additional LOS pointing servo to meet the more stringent pointing requirements. The LOS pointing servo, referred to in JWST as the Fine Guidance Control System (FGCS), will utilize a Fine Guidance Sensor (FGS) as the sensor, and a Fine Steering Mirror (FSM) as the actuator. The FSM is a part of the Optical Telescope Element (OTE) and is in the optical path between the tertiary mirror and the instrument focal plane, while the FGS is part of the Integrated Science Instrument Module (ISIM). The basic Chandra spacecraft bus attitude control and determination architecture, utilizing gyros, star trackers/aspect camera, and reaction wheels, is retained for JWST. This system has achieved pointing stability of better than 0.5 arcseconds. To reach the JWST requirements of milli-arcsecond pointing stability with this ACS hardware, the local FGCS loop is added to the optical path. The FGCS bandwidth is about 2.0 Hz and will therefore attenuate much of the spacecraft ACS induced low frequency jitter. In order to attenuate the higher frequency (greatet than 2.0 Hz) disturbances associated with reaction wheel static and dynamic imbalances, as well as bearing run-out, JWST will employ a two-stage passive vibration isolation system consisting of (1) 7.0 Hz reaction wheel isolators between each reaction wheel and the spacecraft bus, and (2) a 1.0 Hz tower isolator between the spacecraft bus and the Optical Telescope Element (OTE). In order to sense and measure the LOS, the FGS behaves much like an autonomous star tracker that has a very small field of view and uses the optics of the telescope. It performs the functions of acquisition, identification and tracking of stars in its 2.5 x 2.5 arcminute field of view (FOV), and provides the centroid and magnitude of the selected star for use in LOS control. However, since only a single star is being tracked at any time within the FGS FOV there is only tip and tilt information; rotation about the FGS LOS will not be sensed. The FGCS uses the FSM to move the guide star within the FGS FOV and place the centroid of the guide star at any desired position within the FGS focal plane. Using this architecture allows the FGCS to correct the low frequency LOS jitter that is induced by the spacecraft ACS in pitch and yaw, and achieve the milli-arcsecond pointing stability required by JWST. The less stringent ISIM FOV roll performance will be provided solely by the ACS, using the spacecraft gyros and star trackers. Since the FSM is in the optical path, the pointing stabilrty of a science object in any of the instruments will be similar to that of the guide star LOS.

Multifocal necrotising fasciitis: an overlooked entity?

PubMed

El-Khani, Ussamah; Nehme, Jean; Darwish, Ammar; Jamnadas-Khoda, Benjamin; Scerri, Godwin; Heppell, Simon; Bennett, Nicholas

2012-04-01

The aim of the study is to report a case of multi-focal necrotising fasciitis, review research on this subject to identify common aetiological factors and highlight suggestions to improve management. Necrotising fasciitis is a severe, life-threatening soft tissue infection that typically arises from a single area, usually secondary to a minor penetrating injury. Multi-focal necrotising fasciitis, where there is more than one non-contiguous area of necrosis, is much less commonly reported. There are no guidelines specific to the management of multi-focal necrotising fasciitis, and its under-reporting may lead to missed management opportunities. A systematic literature review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol. A search of MEDLINE, OLD MEDLINE and the Cochrane Collaboration was performed from 1966 to March 2011 using 16 search terms. All articles were screened for genuine non-contiguous multi-focal necrotising fasciitis. Of the papers that met this criterion, data on patient demographics, likely inciting injury, presentation time-line, microbial agents, sites affected, objective assessment scores, treatment and outcome were extracted. A total of 31 studies met our inclusion criteria and 33 individual cases of multi-focal necrotising fasciitis were included in the quantitative analysis. About half (52%) of cases were type II necrotising fasciitis; 42% of cases had identifiable inciting injuries; 21% of cases developed multi-focal lesions non-synchronously, of which 86% were type II. Nearly all (94%) of cases had incomplete objective assessment scores. One case identified inflammatory imaging findings prior to clinical necrosis. Multifocality in necrotising fasciitis is likely to be associated with type II disease. We postulate that validated objective tools will aid necrotising fasciitis management pathways that will identify high-risk groups for multifocality and advise early pre-emptive imaging. We recommend the adoption of regional multi-focal necrotising fasciitis registers. Copyright © 2011 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

DESI focal plate mechanical integration and cooling

NASA Astrophysics Data System (ADS)

Lambert, A. R.; Besuner, R. W.; Claybaugh, T. M.; Silber, J. H.

2016-08-01

The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the Universe using the Baryon Acoustic Oscillation technique[1]. The spectra of 40 million galaxies over 14000 sq. deg will be measured during the life of the experiment. A new prime focus corrector for the KPNO Mayall telescope will deliver light to 5000 fiber optic positioners. The fibers in turn feed ten broad-band spectrographs. This paper describes the mechanical integration of the DESI focal plate and the thermal system design. The DESI focal plate is comprised of ten identical petal assemblies. Each petal contains 500 robotic fiber positioners. Each petal is a complete, self-contained unit, independent from the others, with integrated power supply, controllers, fiber routing, and cooling services. The major advantages of this scheme are: (1) supports installation and removal of complete petal assemblies in-situ, without disturbing the others, (2) component production, assembly stations, and test procedures are repeated and parallelizable, (3) a complete, full-scale prototype can be built and tested at an early date, (4) each production petal can be surveyed and tested as a complete unit, prior to integration, from the fiber tip at the focal surface to the fiber slit at the spectrograph. The ten petal assemblies will be installed in a single integration ring, which is mounted to the DESI corrector. The aluminum integration ring attaches to the steel corrector barrel via a flexured steel adapter, isolating the focal plate from differential thermal expansions. The plate scale will be kept stable by conductive cooling of the petal assembly. The guider and wavefront sensors (one per petal) will be convectively cooled by forced flow of air. Heat will be removed from the system at ten liquid-cooled cold plates, one per petal, operating at ambient temperature. The entire focal plate structure is enclosed in an insulating shroud, which serves as a thermal barrier between the heat-generating focal plate components and the ambient air of the Mayall dome, to protect the seeing[2].

Thin film absorption characterization by focus error thermal lensing

NASA Astrophysics Data System (ADS)

Domené, Esteban A.; Schiltz, Drew; Patel, Dinesh; Day, Travis; Jankowska, E.; Martínez, Oscar E.; Rocca, Jorge J.; Menoni, Carmen S.

2017-12-01

A simple, highly sensitive technique for measuring absorbed power in thin film dielectrics based on thermal lensing is demonstrated. Absorption of an amplitude modulated or pulsed incident pump beam by a thin film acts as a heat source that induces thermal lensing in the substrate. A second continuous wave collimated probe beam defocuses after passing through the sample. Determination of absorption is achieved by quantifying the change of the probe beam profile at the focal plane using a four-quadrant detector and cylindrical lenses to generate a focus error signal. This signal is inherently insensitive to deflection, which removes noise contribution from point beam stability. A linear dependence of the focus error signal on the absorbed power is shown for a dynamic range of over 105. This technique was used to measure absorption loss in dielectric thin films deposited on fused silica substrates. In pulsed configuration, a single shot sensitivity of about 20 ppm is demonstrated, providing a unique technique for the characterization of moving targets as found in thin film growth instrumentation.

Characterization of mannitol in Curvularia protuberata hyphae by FTIR and Raman spectromicroscopy.

PubMed

Isenor, Merrill; Kaminskyj, Susan G W; Rodriguez, Russell J; Redman, Regina S; Gough, Kathleen M

2010-12-01

FTIR and Raman spectromicroscopy were used to characterize the composition of Curvularia protuberata hyphae, and to compare a strain isolated from plants inhabiting geothermal soils with a non-geothermal isolate. Thermal IR source images of hyphae have been acquired with a 64 × 64 element focal plane array detector; single point IR spectra have been obtained with synchrotron source light. In some C. protuberata hyphae, we have discovered the spectral signature of crystalline mannitol, a fungal polyol with complex protective roles. With FTIR-FPA imaging, we have determined that the protein content in cells remains fairly constant throughout the length of a hypha, whereas the mannitol is found at discrete, irregular locations. This is the first direct observation of mannitol in intact fungal hyphae. Since the concentration of mannitol in cells varies with respect to position and is not present in all hyphae, this discovery may be related to habitat adaptation, fungal structure and growth stages.

Scaled-model guidelines for formation-flying solar coronagraph missions.

PubMed

Landini, Federico; Romoli, Marco; Baccani, Cristian; Focardi, Mauro; Pancrazzi, Maurizio; Galano, Damien; Kirschner, Volker

2016-02-15

Stray light suppression is the main concern in designing a solar coronagraph. The main contribution to the stray light for an externally occulted space-borne solar coronagraph is the light diffracted by the occulter and scattered by the optics. It is mandatory to carefully evaluate the diffraction generated by an external occulter and the impact that it has on the stray light signal on the focal plane. The scientific need for observations to cover a large portion of the heliosphere with an inner field of view as close as possible to the photospheric limb supports the ambition of launching formation-flying giant solar coronagraphs. Their dimension prevents the possibility of replicating the flight geometry in a clean laboratory environment, and the strong need for a scaled model is thus envisaged. The problem of scaling a coronagraph has already been faced for exoplanets, for a single point source on axis at infinity. We face the problem here by adopting an original approach and by introducing the scaling of the solar disk as an extended source.

Characterization of mannitol in Curvularia protuberata hyphae by FTIR and Raman spectromicroscopy

USGS Publications Warehouse

Isenor, M.; Kaminskyj, S.G.W.; Rodriguez, R.J.; Redman, R.S.; Gough, K.M.

2010-01-01

FTIR and Raman spectromicroscopy were used to characterize the composition of Curvularia protuberata hyphae, and to compare a strain isolated from plants inhabiting geothermal soils with a non-geothermal isolate. Thermal IR source images of hyphae have been acquired with a 64 ?? 64 element focal plane array detector; single point IR spectra have been obtained with synchrotron source light. In some C. protuberata hyphae, we have discovered the spectral signature of crystalline mannitol, a fungal polyol with complex protective roles. With FTIR-FPA imaging, we have determined that the protein content in cells remains fairly constant throughout the length of a hypha, whereas the mannitol is found at discrete, irregular locations. This is the first direct observation of mannitol in intact fungal hyphae. Since the concentration of mannitol in cells varies with respect to position and is not present in all hyphae, this discovery may be related to habitat adaptation, fungal structure and growth stages. ?? 2010 The Royal Society of Chemistry.

Characterization of mannitol in Curvularia protuberata hyphae by FTIR and Raman spectromicroscopy

USGS Publications Warehouse

Rodriguez, Russell J.; Isenor, Merrill; Kaminsky, Susan G.W.; Redman, S.; Gough, Kathleen M.

2010-01-01

FTIR and Raman spectromicroscopy were used to characterize the composition of Curvularia protuberata hyphae, and to compare a strain isolated from plants inhabiting geothermal soils with a non-geothermal isolate. Thermal IR source images of hyphae have been acquired with a 64 × 64 element focal plane array detector; single point IR spectra have been obtained with synchrotron source light. In some C. protuberata hyphae, we have discovered the spectral signature of crystalline mannitol, a fungal polyol with complex protective roles. With FTIR-FPA imaging, we have determined that the protein content in cells remains fairly constant throughout the length of a hypha, whereas the mannitol is found at discrete, irregular locations. This is the first direct observation of mannitol in intact fungal hyphae. Since the concentration of mannitol in cells varies with respect to position and is not present in all hyphae, this discovery may be related to habitat adaptation, fungal structure and growth stages.

Laser bandwidth interlock capable of single pulse detection and rejection

DOEpatents

Armstrong, James P; Telford, Steven James; Lanning, Rodney Kay; Bayramian, Andrew James

2012-10-09

A pulse of laser light is switched out of a pulse train and spatially dispersed into its constituent wavelengths. The pulse is collimated to a suitable size and then diffracted by high groove density multilayer dielectric gratings. This imparts a different angle to each individual wavelength so that, when brought to the far field with a lens, the colors have spread out in a linear arrangement. The distance between wavelengths (resolution) can be tailored for the specific laser and application by altering the number of times the beam strikes the diffraction gratings, the groove density of the gratings and the focal length of the lens. End portions of the linear arrangement are each directed to a respective detector, which converts the signal to a 1 if the level meets a set-point, and a 0 if the level does not. If both detectors produces a 1, then the pulse train is allowed to propagate into an optical system.

Stochastic modelling of animal movement.

PubMed

Smouse, Peter E; Focardi, Stefano; Moorcroft, Paul R; Kie, John G; Forester, James D; Morales, Juan M

2010-07-27

Modern animal movement modelling derives from two traditions. Lagrangian models, based on random walk behaviour, are useful for multi-step trajectories of single animals. Continuous Eulerian models describe expected behaviour, averaged over stochastic realizations, and are usefully applied to ensembles of individuals. We illustrate three modern research arenas. (i) Models of home-range formation describe the process of an animal 'settling down', accomplished by including one or more focal points that attract the animal's movements. (ii) Memory-based models are used to predict how accumulated experience translates into biased movement choices, employing reinforced random walk behaviour, with previous visitation increasing or decreasing the probability of repetition. (iii) Lévy movement involves a step-length distribution that is over-dispersed, relative to standard probability distributions, and adaptive in exploring new environments or searching for rare targets. Each of these modelling arenas implies more detail in the movement pattern than general models of movement can accommodate, but realistic empiric evaluation of their predictions requires dense locational data, both in time and space, only available with modern GPS telemetry.

Lens-free imaging of magnetic particles in DNA assays.

PubMed

Colle, Frederik; Vercruysse, Dries; Peeters, Sara; Liu, Chengxun; Stakenborg, Tim; Lagae, Liesbet; Del-Favero, Jurgen

2013-11-07

We present a novel opto-magnetic system for the fast and sensitive detection of nucleic acids. The system is based on a lens-free imaging approach resulting in a compact and cheap optical readout of surface hybridized DNA fragments. In our system magnetic particles are attracted towards the detection surface thereby completing the labeling step in less than 1 min. An optimized surface functionalization combined with magnetic manipulation was used to remove all nonspecifically bound magnetic particles from the detection surface. A lens-free image of the specifically bound magnetic particles on the detection surface was recorded by a CMOS imager. This recorded interference pattern was reconstructed in software, to represent the particle image at the focal distance, using little computational power. As a result we were able to detect DNA concentrations down to 10 pM with single particle sensitivity. The possibility of integrated sample preparation by manipulation of magnetic particles, combined with the cheap and highly compact lens-free detection makes our system an ideal candidate for point-of-care diagnostic applications.

OAJ 2.6m survey telescope: optical alignment and on-sky evaluation of IQ performances

NASA Astrophysics Data System (ADS)

Lousberg, Gregory P.; Bastin, Christian; Moreau, Vincent; Pirnay, Olivier; Flebus, Carlo; Chueca, Sergio; Iñiguez, César; Ederoclite, Alessandro; Ramió, Héctor V.; Cenarro, A. Javier

2016-08-01

AMOS has recently completed the alignment campaign of the 2.6m telescope for the Observatorio Astrofisico de Javalambre (OAJ). AMOS developed an innovative alignment technique for wide field-of-view telescopes that has been successfully implemented on the OAJ 2.6m telescope with the active support of the team of CEFCA (Centro de Estudios de Física del Cosmos de Aragón). The alignment relies on two fundamental techniques: (1) the wavefront-curvature sensing (WCS) for the evaluation of the telescope aberrations at arbitrary locations in the focal plane, and (2) the comafree point method for the adjustment of the position of the secondary mirror (M2) and of the focal plane (FP). The alignment campaign unfolds in three steps: (a) analysis of the repeatability of the WCS measurements, (b) assessment of the sensitivity of telescope wavefront error to M2 and FP position adjustments, and (c) optical alignment of the telescope. At the end of the campaign, seeing-limited performances are demonstrated in the complete focal plane. With the help of CEFCA team, the image quality of the telescope are investigated with a lucky-imaging method. Image sizes of less than 0.3 arcsec FWHM are obtained, and this excellent image quality is observed over the complete focal plane.

Large incidence angle and defocus influence cat's eye retro-reflector

NASA Astrophysics Data System (ADS)

Zhang, Lai-xian; Sun, Hua-yan; Zhao, Yan-zhong; Yang, Ji-guang; Zheng, Yong-hui

2014-11-01

Cat's eye lens make the laser beam retro-reflected exactly to the opposite direction of the incidence beam, called cat's eye effect, which makes rapid acquiring, tracking and pointing of free space optical communication possible. Study the influence of cat's eye effect to cat's eye retro-reflector at large incidence angle is useful. This paper analyzed the process of how the incidence angle and focal shit affect effective receiving area, retro-reflected beam divergence angle, central deviation of cat's eye retro-reflector at large incidence angle and cat's eye effect factor using geometrical optics method, and presented the analytic expressions. Finally, numerical simulation was done to prove the correction of the study. The result shows that the efficiency receiving area of cat's eye retro-reflector is mainly affected by incidence angle when the focal shift is positive, and it decreases rapidly when the incidence angle increases; the retro-reflected beam divergence and central deviation is mainly affected by focal shift, and within the effective receiving area, the central deviation is smaller than beam divergence in most time, which means the incidence beam can be received and retro-reflected to the other terminal in most time. The cat's eye effect factor gain is affected by both incidence angle and focal shift.

Food for Thought.

ERIC Educational Resources Information Center

Harriman, Cliff; And Others

This document describes "Food for Thought," a multidisciplinary project for grades 5 through 8, using nutrition as a focal point. The program focuses on the popular topic of food to make the study of different cultures and historic periods more relevant. In the program students research the diets and prepare the meals of cultures they…

78 FR 30307 - Statement of Organization, Functions, and Delegations of Authority

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-22

..., 2013. Sherri A. Berger, Chief Operating Officer, Centers for Disease Control and Prevention. [FR Doc... financial management; (19) serves as focal point for emergency operations and deployment; (20) manages and... priorities and objectives and reassesses the role of NCHHSTP field staff assignees to state and local health...

Application of the canonical operator to the description of self-focusing soliton-like solutions of the Kadomtsev-Petviashvili equation

NASA Astrophysics Data System (ADS)

Maslov, V. P.; Shafarevich, A. I.

2011-12-01

A description for the asymptotic soliton-like solution of the Kadomtsev-Petviashvili I equation (KPI equation) in terms of the canonical operator is suggested. This solution can smoothly be continued to the vicinity of the focal point.

A Discovery Chemistry Experiment on Buffers

ERIC Educational Resources Information Center

Kulevich, Suzanne E.; Herrick, Richard S.; Mills, Kenneth V.

2014-01-01

The Holy Cross Chemistry Department has designed and implemented an experiment on buffers as part of our Discovery Chemistry curriculum. The pedagogical philosophy of Discovery Chemistry is to make the laboratory the focal point of learning for students in their first two years of undergraduate instruction. We first pose questions in prelaboratory…

Leadership Excellence through Advancement and Determination Program: A Qualitative Case Study

ERIC Educational Resources Information Center

Perrell, Wendy M.

2012-01-01

Alaska Native leadership development programs are often used to prepare participants and to enhance their leadership potential. The cultural appropriateness of developing Alaska Native leaders through the Western-structured LEAD program was the focal point of this study. Understanding how the LEAD participants adapted to Native and Western…

Solo and Distributed Leadership: Definitions and Dilemmas

ERIC Educational Resources Information Center

Crawford, Megan

2012-01-01

This article discusses solo and distributed leadership. Using the anniversary of "Educational Management Administration & Leadership" as a focal point, it looks back over the last 40 years of "EMAL", using this to frame a wider discussion of the relationship between solo and distributed leadership approaches. It acknowledges other approaches to…

Scattering and Propagation in Random Media

DTIC Science & Technology

1988-01-01

courts porno C~r) module Au champ darns Is pupille A,Ca)4 amplitude complex* Au chomp danms 1. plan focal OMf fouction As tranefert longue point do...instantenie N nosbre minimum d~imagem A utilimer doen les algorithmasm I noabre As taveluros prisontos darns V image courts porno N) noabre do moum

The Impact of Institutional Grant Aid on College Choice

ERIC Educational Resources Information Center

Hurwitz, Michael Drew

2011-01-01

The influence of institutional grant aid on the enrollment behavior of college students has been the focal point of several empirical studies during the past decade. Yet, the extent to which this multibillion dollar per year grant-allocation process influences the matriculation choices of students deciding between multiple institutions remains…

Ghosts of the Past: Character Journals from the Titanic.

ERIC Educational Resources Information Center

LaBonty, Jan

1998-01-01

Describes an assignment used in a reading/language arts course for elementary education majors that uses Robert Ballard's factual book "Exploring the Titanic" as a focal point for a character journal assignment. Notes students' enthusiastic responses to this assignment. Describes how this assignment could be adapted to a middle- or…

Language Choice in Multilingual Encounters in Transnational Workplaces

ERIC Educational Resources Information Center

Kingsley, Leilarna

2013-01-01

This paper is based on research conducted in banks in the international banking centre of Luxembourg. Operating in the globalised context of international banking and multilingual Luxembourg, financial institutions are an ideal focal point for investigating policy and practices in complex multilingual and transnational work spaces. Two theoretical…

48 CFR 304.7001 - Numbering acquisitions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... contracting office identification codes currently in use is contained in the DCIS Users' Manual, available at... than one code may apply in a specific situation, or for additional codes, refer to the DCIS Users' Manual or consult with the cognizant DCIS coordinator/focal point for guidance on which code governs...

Afterschool Essentials: Research and Polling

ERIC Educational Resources Information Center

Afterschool Alliance, 2013

2013-01-01

This 2-page resource summarizes statistical findings highlighting the need and demand for more afterschool programs for children and youth. Focal points include: (1) The Afterschool Hours in America; (2) Afterschool Offers a Range of Benefits to Youth and their Families; (3) Afterschool Supports Student Success; (4) Afterschool Programs Are Seen…

Spatial Distribution and Morphology of Sediments in Texas Southern High Plains Playa Wetlands

USDA-ARS?s Scientific Manuscript database

Playas are depressional geomorphic features on the U.S. High Plains and about 20,000 Southern High Plains playa wetlands serve as runoff catchment basins, which are thought to be focal points of Ogallala aquifer recharge. Sediments in playas can alter biodiversity services, impede aquifer recharge,...

Origins of Coordinate Searching.

ERIC Educational Resources Information Center

Kilgour, Frederick G.

1997-01-01

Reviews the origins of post-coordinate searching and emphasizes that the focal point should be on the searcher, not on the item being indexed. Highlights include the history of the term information retrieval; edge notched punch cards; the "peek-a-boo" system; the Uniterm system; and using computers to search for information. (LRW)

Inviting other professions to help reduce wildfire property losses

Treesearch

A. Fege; J. Absher

2007-01-01

Preventing structure loss has become a major focal point of wildland firefighting. Most days it feels like wildland fire professionals and land managers are become more and more responsible for reducing property losses in the wildland/urban interface (WUI).What if this impression-and reality-could change?

Virtual Schools in the U.S. 2017

ERIC Educational Resources Information Center

Molnar, Alex; Miron, Gary; Gulosino, Charisse; Shank, Christopher; Davidson, Caryn; Barbour, Michael; Huerta, Luis; Shafter, Sheryl Rankin; Rice, Jennifer King; Nitkin, David

2017-01-01

In the five years since the first National Education Policy Center (NEPC) "Annual Report on Virtual Education" was released in 2013, virtual education has continued to be a focal point for policymakers. Proponents argue that virtual education can expand student choices and improve the efficiency of public education. In particular,…

Identification of methyl farnesoate from the hemolymph of insects

USDA-ARS?s Scientific Manuscript database

Juvenile hormones (JH) have been a focal point of study in insect endocrinology for more than 80 years and are implicated in regulation of more physiological and behavioral functions than any other insect hormone. Indeed, evidence has suggested that JHs are the only sesquiterpene hormone products s...

Blind Students Learn Food Skills

ERIC Educational Resources Information Center

Pass, Gisela; Uhlinger, Susan J.

1970-01-01

The problems of cooking and working in the kitchen were the focal point of a series of six lessons given by the Hampden County, Massachusetts, Extension Service for 16 blind men and women. The basic purpose of the course was to help them develop self-reliance in relation to meal preparation. (Author/MF)

Testing wetland axioms at a watershed scale: Case studies of the aggregate hydrologic effects of non-adjacent wetlands

EPA Science Inventory

Wetlands not adjacent to streams (i.e. “non-adjacent wetlands”) are hypothesized to affect downgradient hydrology in a number of ways. Non-adjacent wetlands may, for example, attenuate peak flows, serve as focal points for groundwater recharge, and decrease streamflow...

Sharing a Vision.

ERIC Educational Resources Information Center

Cox, Susan M.

1999-01-01

Explains how one New Orleans (LA) school is making a positive difference in a low-income community by serving as the community's focal point and providing the community access to a public library, computers, and a learning center. Highlights the development of the Greater New Orleans Education Foundation and its assessment process, designed to…

Immersive Educational Technology: Changing Families and Learning.

ERIC Educational Resources Information Center

Ehrich, Roger W.; McCreary, Faith

Since the popularization of networked computing that began in 1993, many excited educators have employed networked computers to improve motivation and learning in the classroom. Computers have also become a focal point for the improvement of instruction through the introduction of teaching methods that better support constructivist learning. While…

Standards Writers Wade into Curriculum

ERIC Educational Resources Information Center

Gewertz, Catherine

2011-01-01

New guidelines on crafting curriculum materials for the common standards in English/language arts are reigniting debate about how to ensure a marketplace of good instructional materials for the new standards without crossing the line into telling teachers how to teach. The focal point of the conversations is a set of "publishers' criteria" issued…

A Vital Equation: School + Museum + Community = Learning Through the Arts

ERIC Educational Resources Information Center

Davis, Cecille

1976-01-01

Article described Project "Turn-On," which took place at the Cloisters in New York City, designed to introduce children and teachers in District 6 in upper Manhattan to the beautiful and unusual "neighborhood" museum that became the focal point for active learning in many areas. (Author/RK)

18 CFR 740.1 - Purpose and scope.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 18 Conservation of Power and Water Resources 2 2014-04-01 2014-04-01 false Purpose and scope. 740.1 Section 740.1 Conservation of Power and Water Resources WATER RESOURCES COUNCIL STATE WATER... focal point for the management of water and related land resources, this part establishes guidelines for...