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Sample records for linear slit scanning

  1. Virtual slit scanning microscopy.

    PubMed

    Fiolka, Reto; Stemmer, Andreas; Belyaev, Yury

    2007-12-01

    We present a novel slit scanning confocal microscope with a CCD camera image sensor and a virtual slit aperture for descanning that can be adjusted during post-processing. A very efficient data structure and mathematical criteria for aligning the virtual aperture guarantee the ease of use. We further introduce a method to reduce the anisotropic lateral resolution of slit scanning microscopes. System performance is evaluated against a spinning disk confocal microscope on identical specimens. The virtual slit scanning microscope works as the spinning disk type and outperforms on thick specimens. PMID:17891411

  2. Detection of urinary stones at reduced radiation exposure: a phantom study comparing computed radiography and a low-dose digital radiography linear slit scanning system

    PubMed Central

    Szucs-Farkas, Zsolt; Chakraborty, D. P.; Thoeny, Harriet C.; Loupatatzis, Christos; Vock, Peter; Harald, Bonel

    2010-01-01

    Objective In this experimental study we assessed the diagnostic performance of linear slit scanning radiography (LSSR) compared to conventional computed radiography (CR) in the detection of urinary calculi in an anthropomorphic phantom imitating patients weighing approximately 58 to 88 kg. Conclusion Compared to computed radiography, LSSR is superior in the detection of urinary stones and may be used for pretreatment localization and follow-up at a lower patient exposure. PMID:19457787

  3. Imaging of double slit interference by scanning gate microscopy

    NASA Astrophysics Data System (ADS)

    Kolasiński, K.; Szafran, B.; Nowak, M. P.

    2014-10-01

    We consider scanning gate microscopy imaging of the double slit interference for a pair of quantum point contacts (QPCs) defined within the two-dimensional electron gas. The interference is clearly present in the scattered electron wave functions for each of the incident subbands. Nevertheless, we find that the interference is generally missing in the experimentally accessible conductance maps for many incident subbands. We explain this finding on the basis of the Landauer approach. A setup geometry allowing for observation of the double slit interference by scanning gate microscopy is proposed.

  4. Non-linear Young's double-slit experiment.

    PubMed

    San Roman, Julio; Ruiz, Camilo; Perez, Jose Antonio; Delgado, Diego; Mendez, Cruz; Plaja, Luis; Roso, Luis

    2006-04-01

    The Young's double slit experiment is recreated using intense and short laser pulses. Our experiment evidences the role of the non-linear Kerr effect in the formation of interference patterns. In particular, our results evidence a mixed mechanism in which the zeroth diffraction order of each slit are mainly affected by self-focusing and self-phase modulation, while the higher orders propagate linearly. Despite of the complexity of the general problem of non-linear propagation, we demonstrate that this experiment retains its simplicity and allows for a geometrical interpretation in terms of simple optical paths. In consequence, our results may provide key ideas on experiments on the formation of interference patterns with intense laser fields in Kerr media.

  5. Parameter estimation for slit-type scanning sensors

    NASA Technical Reports Server (NTRS)

    Fowler, J. W.; Rolfe, E. G.

    1981-01-01

    The Infrared Astronomical Satellite, scheduled for launch into a 900 km near-polar orbit in August 1982, will perform an infrared point source survey by scanning the sky with slit-type sensors. The description of position information is shown to require the use of a non-Gaussian random variable. Methods are described for deciding whether separate detections stem from a single common source, and a formulism is developed for the scan-to-scan problems of identifying multiple sightings of inertially fixed point sources for combining their individual measurements into a refined estimate. Several cases are given where the general theory yields results which are quite different from the corresponding Gaussian applications, showing that argument by Gaussian analogy would lead to error.

  6. A pulse generator simulating slit-scan chromosome analysis signals.

    PubMed

    Weier, H U; Eisert, W G

    1986-01-01

    A simple circuit is described for generating a variety of electronic pulses to test hardware and software for slit-scan chromosome analysis in a flow cytometer. The pulse shape can be changed to have different numbers of local minima, thereby simulating fluorescence pulses from acrocentric, monocentric, and dicentric chromosomes. Long pulses simulate aggregates of chromosomes. The pulse repetition rate as well as the pulse amplitude is variable. Although the circuitry is built with only three integrated circuits, the pulse-to-pulse variation in shape and height is quite small. After digitization of the analog signals, the constructed histograms of pulse integrals show a relative coefficient of variation below 1%. This signal generator provides a valuable tool for a number of electronic test applications that would otherwise require expensive standard particles analyzed in a well-tuned flow cytometer.

  7. Optics and experimental resolution of the Heidelberg slit-scan flow fluorometer

    NASA Astrophysics Data System (ADS)

    Hausmann, Michael; Wickert, Burkhard; Vogel, Michael; Schurwanz, Michael; Doelle, Juergen; Wolf, Dietmar; Aldinger, Klaus; Cremer, Christoph G.

    1996-01-01

    Slit-scan flow fluorometry is a laser-technological approach for accelerated screening and sorting of fluorescence labelled metaphase chromosomes. Details of the optics of the Heidelberg slit-scan sorter are presented. In a fluid stream the fluorescence labelled chromosomes rapidly pass one at a time by a scanning laser beam. The laser can be focused by a less complex optic consisting of only a few commercially available lenses. The laser intensity distribution around the focus was measured for 488 nm for two lens configurations. Although the light distribution obtained by such an optic is normally not aberration free, the requirements of a 'ribbonlike' shape in the center of the fluid stream can be fulfilled. Since the chromosomes are oriented perpendicularly to the laser beam by hydrodynamic focusing of the fluid stream, the fluorescence intensity along the chromosome axis can be measured time (equals spatially) resolved. According to their intensity profiles the chromosomes can be classified. Signal processing of the profiles can be performed in less than 600 microseconds, so that in the order of hundred chromosomes per second can be sorted out by a computer controlled electro-acoustic sorting unit. The final spatial resolution of a slit-scan flow sorter is not only affected by the focusing optics of the laser but also by the fluid stream, the detection optics and electronics, as well as by the computer analysis algorithm. Calculations often consider only the optics under ideal conditions. Here, a method is shown how to estimate the overall resolution of a slit-scan flow fluorometer experimentally. According to this criterion the resolution of the Heidelberg slit-scan sorter for 488 nm fluorescence excitation was estimated to be 2.4 micrometer in its basic optical configuration and 1.7 micrometer with additional correction of chromatic aberration effects.

  8. Line-scanning fiber bundle endomicroscopy with a virtual detector slit.

    PubMed

    Hughes, Michael; Yang, Guang-Zhong

    2016-06-01

    Coherent fiber bundles can be used to relay the image plane from the distal tip of an endomicroscope to an external confocal microscopy system. The frame rate is therefore determined by the speed of the microscope's laser scanning system which, at 10-20 Hz, may be undesirably low for in vivo clinical applications. Line-scanning allows an increase in the frame rate by an order of magnitude in exchange for some loss of optical sectioning, but the width of the detector slit cannot easily be adapted to suit different imaging conditions. The rolling shutter of a CMOS camera can be used as a virtual detector slit for a bench-top line-scanning confocal microscope, and here we extend this idea to endomicroscopy. By synchronizing the camera rolling shutter with a scanning laser line we achieve confocal imaging with an electronically variable detector slit. This architecture allows us to acquire every other frame with the detector slit offset by a known distance, and we show that subtracting this second image leads to improved optical sectioning. PMID:27375942

  9. Line-scanning fiber bundle endomicroscopy with a virtual detector slit

    PubMed Central

    Hughes, Michael; Yang, Guang-Zhong

    2016-01-01

    Coherent fiber bundles can be used to relay the image plane from the distal tip of an endomicroscope to an external confocal microscopy system. The frame rate is therefore determined by the speed of the microscope’s laser scanning system which, at 10-20 Hz, may be undesirably low for in vivo clinical applications. Line-scanning allows an increase in the frame rate by an order of magnitude in exchange for some loss of optical sectioning, but the width of the detector slit cannot easily be adapted to suit different imaging conditions. The rolling shutter of a CMOS camera can be used as a virtual detector slit for a bench-top line-scanning confocal microscope, and here we extend this idea to endomicroscopy. By synchronizing the camera rolling shutter with a scanning laser line we achieve confocal imaging with an electronically variable detector slit. This architecture allows us to acquire every other frame with the detector slit offset by a known distance, and we show that subtracting this second image leads to improved optical sectioning. PMID:27375942

  10. Fast slit-scan method for MTF and MRTD characterization in the HITL environment

    NASA Astrophysics Data System (ADS)

    Smith, James L.

    1996-06-01

    A method based on the line scan of a narrow slit pattern is described for MTF and MRTD determinations. A digital signal analyzer and automatic computer worksheet are utilized for executing this methodology. This single-scan procedure can replace a series of measurements with different sized bar patterns, and it facilitates rapid imaging system characterization for weapons scheduled for intensive hardware-in-the-loop testing. The challenge of this method was to overcome the practical data processing problems encountered. MRTD determinations using the slit-scan method agree very well with conventional bar pattern measurements and has been validated for a variety of imaging sensors. The automatic worksheet analysis determines MTF and both the objective, line scan MRTD as well as the 'eye-brain MRTD' based on a human vision model.

  11. Non-Linear Seismic Response of Reinforced Concrete Slit Shear Walls

    NASA Astrophysics Data System (ADS)

    KWAN, A. K. H.; DAI, H.; CHEUNG, Y. K.

    1999-09-01

    The reinforced concrete slit shear wall system has been introduced recently as a new breed of earthquake resistant structures. Some theoretical and experimental investigations have been conducted to study the behaviour of isolated connecting beams and slit shear wall models under static load, but little work has been carried out to investigate the dynamic behaviour of the structural system. In this paper, the non-linear seismic response of slit shear walls under earthquake excitation is analyzed. Based on a simplified structural model, which is shown to have sufficient accuracy for slit shear wall structures, the influence of the elasto-plastic behaviour of the connecting beams on the dynamic response of the slit shear wall structure is evaluated. The results reveal that yielding of the connecting beams can significantly reduce the deflection response of the slit shear wall structure and the seismic loading induced on it. Moreover, there appears to be an optimum yield strength value for the connecting beams that would lead to the best overall seismic performance of the slit shear wall system.

  12. Scatter correction method for cone-beam CT based on interlacing-slit scan

    NASA Astrophysics Data System (ADS)

    Huang, Kui-Dong; Zhang, Hua; Shi, Yi-Kai; Zhang, Liang; Xu, Zhe

    2014-09-01

    Cone-beam computed tomography (CBCT) has the notable features of high efficiency and high precision, and is widely used in areas such as medical imaging and industrial non-destructive testing. However, the presence of the ray scatter reduces the quality of CT images. By referencing the slit collimation approach, a scatter correction method for CBCT based on the interlacing-slit scan is proposed. Firstly, according to the characteristics of CBCT imaging, a scatter suppression plate with interlacing slits is designed and fabricated. Then the imaging of the scatter suppression plate is analyzed, and a scatter correction calculation method for CBCT based on the image fusion is proposed, which can splice out a complete set of scatter suppression projection images according to the interlacing-slit projection images of the left and the right imaging regions in the scatter suppression plate, and simultaneously complete the scatter correction within the flat panel detector (FPD). Finally, the overall process of scatter suppression and correction is provided. The experimental results show that this method can significantly improve the clarity of the slice images and achieve a good scatter correction.

  13. Contrast analysis of near-field scanning microscopy using a metal slit probe at millimeter wavelengths

    NASA Astrophysics Data System (ADS)

    Nozokido, Tatsuo; Ishino, Manabu; Seto, Ryosuke; Bae, Jongsuck

    2015-09-01

    We describe an analytical method for investigating the signal contrast obtained in near-field scanning microscopy using a metal slit probe. The probe has a slit-like aperture at the open end of a rectangular or a parallel plate waveguide. In our method, the electromagnetic field around the metal slit aperture at the probe tip is calculated from Maxwell's equations in the Fourier domain in order to derive the electrical admittance of a sample system consisting of layered dielectrics as seen from the probe tip. A simple two-port electrical circuit terminated by this admittance is then established to calculate the complex reflection coefficient of the probe as a signal. The validity of the method is verified at millimeter wavelengths by a full-wave high frequency 3-D finite element modeler and also by experiment. The signal contrast when varying the short dimension of the slit aperture, the separation between the probe tip and the sample, and the sample thickness are successfully explained in terms of the variation in the product of the admittance and the characteristic impedance of the waveguide at the probe tip. In particular, the cause of the local minimum in the signal intensity when varying the separation is clarified.

  14. Expectation values for low resolution flow slit scan prescreening: influence of nuclear shape and DNA density

    SciTech Connect

    Mullaney, P.F.; Mann, R.; Seger, G.; Achatz, M.

    1981-01-01

    High resolution fluorescent image analysis has been conducted with mithramycin stained cells from clinical gynecological specimens. Features characteristic of the usual, low resolution, one dimensional slit-scan flow cytometric measurements were extracted from 250 high resolution nuclear images. In addition to the measurement of the usual parameters, nuclear ellipticity and DNA density (DNA per unit nuclear size) were also determined. Preliminary results indicate both these features offer increased discrimination. When nuclear shape is included as a global feature, at least 77% of the diagnostic cells can be distinguished from normals, with no overlap. Both features hold promise for improving the discrimination possible with flow cytometry.

  15. David Maurice's contributions to optical ophthalmic instrumentation: roots of the scanning slit clinical confocal microscope.

    PubMed

    Masters, Barry R

    2004-03-01

    This paper explores the seminal contributions of David Maurice to the field of ophthalmic instrumentation. His development of the specular microscope, the scanning slit optical confocal microscope, and the corneal microfluorometer resulted in advances in our understanding of corneal morphology, physiology, and pathology. The development of the scanning slit, clinical confocal microscope is not a new paradigm or a paradigm shift, but a continuous series of interlinked technical advances from the early work of Vogt to Thaer's development of a clinical confocal microscope. For each instrument both the connection to the prior work of others and the unique advances are discussed and contrasted. This paper develops the connections and parallel developments in the instrument developments of Goldmann, Maurice, Svishchev, Baer, Koester, Masters, and Thaer. The evidence in support of the thesis consists of published papers, patents, personal communication, and study of Goldmann's book collection in Bern. A second theme is that knowledge of physics is a prerequisite for optical instrument development in ophthalmology. David Maurice had a university degree in physics and Hans Goldmann learned physics from his books. The contributions of David Maurice to optical instrumentation follow the major contributions of Goldmann and facilitated and stimulated other scientists who acknowledged their important intellectual debt to David Maurice.

  16. Breadboard linear array scan imager program

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The performance was evaluated of large scale integration photodiode arrays in a linear array scan imaging system breadboard for application to multispectral remote sensing of the earth's resources. Objectives, approach, implementation, and test results of the program are presented.

  17. Imaging of aphakic intraocular lens with a slit-scanning tomography system

    NASA Astrophysics Data System (ADS)

    Oliveira, Cristina M.; Almeida, J. B.; Franco, S.

    2011-05-01

    Nowadays, cataract extraction with IOL implantation aims not only to restore the crystalline lens' transparency, but also to improve patients' retinal image quality. The refractive outcome and visual quality in pseudophakic eyes is mainly determined by the combination of corneal and internal optics resulting from the implanted IOLs. The optical function of the IOLs depends on its position in the eye. The IOL distance to the corneal apex determines the optical power needed for optical correction. In this paper it is described the usage of a slit-scanning imaging system to determine IOL positioning. Through the projection of the light from a slit onto the eye, this tomography system allows to acquire multiple sections of the anterior eye segment, at different meridians. The developed system's software corrects geometric and optical distortion of the images and provides 3-dimentional models of the eye's structures from the 2-dimensional sections. With this noninvasive technique, cross-sectional images of an eye with an aphakic IOL were obtained in order to reconstruct its 3- dimensional model of the lens and assess its position in the anterior segment camera.

  18. Estimation of the frequency of malformed sperm by slit scan flow cytometry

    SciTech Connect

    Halamka, J.; Gray, J.W.; Gledhill, B.L.; Lake, S.; Wyrobek, A.J.

    1984-01-01

    An investigation was made of the utility of Slit Scan Flow Cytometry (SSFCM) for measuring the frequencies of malformed sperm heads in control and mutagen treated B6C3F1/CRL mice. In SSFCM, fluorescence profiles of sperm heads stained with the DNA-specific fluorescent dye acriflavine were recorded for sperm flowing lengthwise through a 2.5-..mu..m-thick laser beam. Malformed sperm were detected as having fluorescence profiles that differed substantially from an average fluorescence profile for sperm from untreated mice. Fluorescence profiles were measured for 500 sperm per mouse from five control mice, five mice injected intraperitoneally daily for 5 days with a total of 375 mg/kg of body weight methyl methane sulfonate (MMS), and for 30 mice injected intraperitoneally daily for 5 days with total doses of procarbazine ranging from 125 mg/kg to 1250 mg/kg. Sperm were collected from the caudae epididymides 35 days after the last injection. Frequencies of malformed sperm in these samples were also estimated by visual analysis. All samples were analyzed in double blind fashion. The visual and SSFCM malformed sperm frequencies for the samples from control, MMS-treated, and procarbazine-treated mice were correlated. A dose effect was seen with both the visual and SSFCM estimates for the sperm from the procarbazine-treated mice. 8 references 3 figures.

  19. Quantification of mammalian sperm morphology by slit-scan flow cytometry

    SciTech Connect

    Benaron, D.A.; Gray, J.W.; Gledhill, B.L.; Lake, S.; Wyrobek, A.J.; Young, I.T.

    1982-01-01

    The head shapes of mammalian sperm were measured by slit-scan flow cytometry (SSFCM). Fluorescence profiles were measured for sperm from mice, rabbits, hamsters, and bulls, and for sperm from mice, rabbits, hamsters, and bulls, and for sperm from mice exposed to testicular x-irradiation from 0 to 900 rads. Some of the fluorescence profiles for sperm from the irradiated mice differed significantly from the profiles usually measured for sperm from unexposed mice. An algorithm was developed to determine the frequency of these sperm. The estimated frequencies of atypical profiles correlated well with the frequencies of abnormally shaped sperm determined by microscopic scoring. The maximum SSFCM sensitivity was not as high as that for the visual assay. However, only 100 profiles were measured by SSFCM at each dose while at least 500 sperm were scored visually at each dose. The sensitivity of the SSFCM assay should be increased substantially by measuring more profiles. The objective nature of SSFCM coupled with the high correlation with results from the visually based assay of morphology suggests the use of SSFCM to measure frequencies of misshapen sperm when testing for mutagens or monitoring for effects of environmental contaminants.

  20. Quantification of mammalian sperm morphology by slit-scan flow cytometry

    SciTech Connect

    Benaron, D.A.; Gray, J.W.; Gledhill, B.L.; Lake, S.; Wyrobek, A.J.; Young, I.T.

    1982-03-01

    The head shapes of mammalian sperm have been measured by slit-scan flow cytometry (SSFCM). In this approach, the distribution of fluorescence along acriflavine stained mammalian sperm is recorded and used as a measure of head shape. Fluorescence profiles were measured for sperm from mice, rabbits, hamsters, and bulls, and for sperm from mice exposed to testicular x-irradiation from 0 to 900 rads. The profiles for sperm from nonirradiated animals were characteristic of each species and were reproducible from sperm to sperm. Some of the fluorescence profiles for sperm from the irradiated mice differed significantly from the profiles usually measured for sperm from exposed mice. An algorithm was developed to determine the frequency of these sperm. The estimated frequencies of atypical profiles correlated well (r . 0.99) with the frequencies of abnormally shaped sperm determined by microscopic scoring. The maximum SSFCM sensitivity (minimum detectable dose . 199 rad) was not as high as that for the visual assay (minimum detectable dose . 116 rad). However, only 100 profiles were measured by SSFCM at each dose while at least 500 sperm were scored visually at each dose. The sensitivity of the SSFCM assay should be increased substantially by measuring more profiles. The objective nature of SSFCM couple with the high correlation with results from the visually based assay of morphology suggests the use of SSFCM to measure frequencies of misshapen sperm when testing for mutagens or monitoring for effects of environmental contaminants.

  1. A Linear Magnetic Field Scan Driver

    PubMed Central

    QUINE, RICHARD W.; CZECHOWSKI, TOMASZ; EATON, GARETH R.

    2009-01-01

    A linear magnetic field scan driver was developed to provide a rapidly scanning magnetic field for use in electron paramagnetic resonance (EPR) spectroscopy. The driver consists of two parts: a digitally synthesized ramp waveform generator and a power amplifier to drive the magnetic field coils. Additionally, the driver provides a trigger signal to a data collection digitizer that is synchronized to the ramp waveform. The driver can also drive an arbitrary current waveform supplied from an external source. The waveform generator is computer controlled through a serial data interface. Additional functions are controlled by the user from the driver front panel. The frequency and amplitude of the waveform are each separately controlled with 12-bit resolution (one part in 4,096). Several versions of the driver have been built with different frequency and amplitude ranges. Frequencies range from 500 to 20,000 Hz. Field sweep amplitudes range up to 80 Gpp. This article also gives a brief description of the field coils that are driven by the driver. PMID:19838315

  2. Development of a two-parameter slit-scan flow cytometer for screening of normal and aberrant chromosomes: application to a karyotype of Sus scrofa domestica (pig)

    NASA Astrophysics Data System (ADS)

    Hausmann, Michael; Doelle, Juergen; Arnold, Armin; Stepanow, Boris; Wickert, Burkhard; Boscher, Jeannine; Popescu, Paul C.; Cremer, Christoph

    1992-07-01

    Laser fluorescence activated slit-scan flow cytometry offers an approach to a fast, quantitative characterization of chromosomes due to morphological features. It can be applied for screening of chromosomal abnormalities. We give a preliminary report on the development of the Heidelberg slit-scan flow cytometer. Time-resolved measurement of the fluorescence intensity along the chromosome axis can be registered simultaneously for two parameters when the chromosome axis can be registered simultaneously for two parameters when the chromosome passes perpendicularly through a narrowly focused laser beam combined by a detection slit in the image plane. So far automated data analysis has been performed off-line on a PC. In its final performance, the Heidelberg slit-scan flow cytometer will achieve on-line data analysis that allows an electro-acoustical sorting of chromosomes of interest. Interest is high in the agriculture field to study chromosome aberrations that influence the size of litters in pig (Sus scrofa domestica) breeding. Slit-scan measurements have been performed to characterize chromosomes of pigs; we present results for chromosome 1 and a translocation chromosome 6/15.

  3. Clinical applications of a real-time scanning-slit confocal microscope designed for real-time observations of the in-vivo human cornea

    NASA Astrophysics Data System (ADS)

    Masters, Barry R.

    1995-05-01

    We describe a new, real-time, flying slit confocal microscope, that has unique features and imaging characteristics for in vivo human ocular imaging. In vivo real-time confocal microscopy is currently used to investigate the tear film, renewal of the ocular surface, the role of epithelial innervation in epithelial cell proliferation, wound healing, kinetics of drug penetration, the effects of laser refractive surgery on the keratocyte activation and distribution in the stroma, and the nature of endothelial defects. The following clinical examples will be presented and discussed: confocal microscopy of normal human basal and wing cells in the epithelium, confocal microscopy of lamellar and penetrating corneal grafts, confocal microscopy of corneal ulcer, confocal microscopy of scar formation after herpes keratitis, and confocal microscopy of corneal innervation. The use of scanning slit confocal microscopes has unique advantages over other instrumental systems based on pinhole-containing Nipkow disks (tandem-scanning confocal microscopes) for clinical in vivo confocal microscopy.

  4. LINEAR SCANNING METHOD BASED ON THE SAFT COARRAY

    SciTech Connect

    Martin, C. J.; Martinez-Graullera, O.; Romero, D.; Ullate, L. G.; Higuti, R. T.

    2010-02-22

    This work presents a method to obtain B-scan images based on linear array scanning and 2R-SAFT. Using this technique some advantages are obtained: the ultrasonic system is very simple; it avoids the grating lobes formation, characteristic in conventional SAFT; and subaperture size and focussing lens (to compensate emission-reception) can be adapted dynamically to every image point. The proposed method has been experimentally tested in the inspection of CFRP samples.

  5. A light sheet confocal microscope for image cytometry with a variable linear slit detector

    NASA Astrophysics Data System (ADS)

    Hutcheson, Joshua A.; Khan, Foysal Z.; Powless, Amy J.; Benson, Devin; Hunter, Courtney; Fritsch, Ingrid; Muldoon, Timothy J.

    2016-03-01

    We present a light sheet confocal microscope (LSCM) capable of high-resolution imaging of cell suspensions in a microfluidic environment. In lieu of conventional pressure-driven flow or mechanical translation of the samples, we have employed a novel method of fluid transport, redox-magnetohydrodynamics (redox-MHD). This method achieves fluid motion by inducing a small current into the suspension in the presence of a magnetic field via electrodes patterned onto a silicon chip. This on-chip transportation requires no moving parts, and is coupled to the remainder of the imaging system. The microscopy system comprises a 450 nm diode 20 mW laser coupled to a single mode fiber and a cylindrical lens that converges the light sheet into the back aperture of a 10x, 0.3 NA objective lens in an epi-illumination configuration. The emission pathway contains a 150 mm tube lens that focuses the light onto the linear sensor at the conjugate image plane. The linear sensor (ELiiXA+ 8k/4k) has three lateral binning modes which enables variable detection aperture widths between 5, 10, or 20 μm, which can be used to vary axial resolution. We have demonstrated redox-MHD-enabled light sheet microscopy in suspension of fluorescent polystyrene beads. This approach has potential as a high-throughput image cytometer with myriad cellular diagnostic applications.

  6. Slow-scan operation of long linear CCD arrays

    NASA Technical Reports Server (NTRS)

    Vicars-Harris, M.

    1975-01-01

    Linear CCD arrays used singly or in optically butted assemblies permit practical implementation of long line array systems with 6000 or more picture elements per line with readout rates in excess of 5 MHz. Display and tape recording of slow scan imagery with over 1000 picture elements per line also presents unique challenges. This paper discusses performance results and the operation of 1728-element CCD arrays for generation of high resolution slow scan imagery and some approaches for recording and display of the imagery. The implication of dark current and its control are discussed.

  7. Linearization of scan velocity of resonant vibrating-mirror beam deflectors

    DOEpatents

    Yeung, E.S.; Chen, S.L.

    1991-01-15

    A means and method for producing linearization of scan velocity of resonant vibrating-mirror beam deflectors in laser scanning system including presenting an elliptical convex surface to the scanning beam to reflect the scanning beam to the focal plane of the scanning line. The elliptical surface is shaped to produce linear velocity of the reflective scanning beam at the focal plane. Maximization of linearization is accomplished by considering sets of criteria for different scanning applications. 6 figures.

  8. Using Stage- and Slit-Scanning to Improve Contrast and Optical Sectioning in Dual-View Inverted Light Sheet Microscopy (diSPIM).

    PubMed

    Kumar, Abhishek; Christensen, Ryan; Guo, Min; Chandris, Panos; Duncan, William; Wu, Yicong; Santella, Anthony; Moyle, Mark; Winter, Peter W; Colón-Ramos, Daniel; Bao, Zhirong; Shroff, Hari

    2016-08-01

    Dual-view inverted selective plane illumination microscopy (diSPIM) enables high-speed, long-term, four-dimensional (4D) imaging with isotropic spatial resolution. It is also compatible with conventional sample mounting on glass coverslips. However, broadening of the light sheet at distances far from the beam waist and sample-induced scattering degrades diSPIM contrast and optical sectioning. We describe two simple improvements that address both issues and entail no additional hardware modifications to the base diSPIM. First, we demonstrate improved diSPIM sectioning by keeping the light sheet and detection optics stationary, and scanning the sample through the stationary light sheet (rather than scanning the broadening light sheet and detection plane through the stationary sample, as in conventional diSPIM). This stage-scanning approach allows a thinner sheet to be used when imaging laterally extended samples, such as fixed microtubules or motile mitochondria in cell monolayers, and produces finer contrast than does conventional diSPIM. We also used stage-scanning diSPIM to obtain high-quality, 4D nuclear datasets derived from an uncompressed nematode embryo, and performed lineaging analysis to track 97% of cells until twitching. Second, we describe the improvement of contrast in thick, scattering specimens by synchronizing light-sheet synthesis with the rolling, electronic shutter of our scientific complementary metal-oxide-semiconductor (sCMOS) detector. This maneuver forms a virtual confocal slit in the detection path, partially removing out-of-focus light. We demonstrate the applicability of our combined stage- and slit-scanning- methods by imaging pollen grains and nuclear and neuronal structures in live nematode embryos. All acquisition and analysis code is freely available online. PMID:27638693

  9. Topological and metric properties of linear and circular DNA chains in nano-slits and nano-channels

    NASA Astrophysics Data System (ADS)

    Orlandini, Enzo; Micheletti, Cristian

    2014-03-01

    Motivated by recent advancements in single DNA molecule experiments, based on nanofluidic devices, we investigate numerically the metric and topological properties of a modelof open and circular DNA chains confined inside nano-slits and nano-channles. The results reveal an interesting characterization of the metric crossover behaviour in terms of the abundance, type and length of occuring knots. In particular we find that the knotting probability is nonmonotonic for increasing confinement and can be largely enhanced or suppressed, compared to the bulk case, by simply varying the slit or channel trasversal dimension. The observed knot population consists of knots that are far simpler than for DNA chains in spherical (i.e. cavities or capsids) confinement. These results suggest that nanoslits and nanochannels can be properly designed to produce open DNA chains hosting simple knots or to sieve DNA rings according to their knotted state. Finally we discuss the implications that the presence of knots may have on the dynamical properties of confined DNA chains such as chain elongation, injection/ejection processes and entanglement relaxation. We acknowledge financial support from the Italian ministry of education, grant PRIN 2010HXAW77.

  10. Linearization of scan velocity of resonant vibrating-mirror beam deflectors

    DOEpatents

    Yeung, Edward S.; Chen, Shun-Le

    1991-01-15

    A means and method for producing linerization of scan velocity of resonant vibrating-mirror beam deflectors in laser scanning system including presenting an elliptical convex surface to the scanning beam to reflect the scanning beam to the focal plane of the scanning line. The elliptical surface is shaped to produce linear velocity of the reflective scanning beam at the focal plane. Maximization of linerization is accomplished by considering sets of criteria for different scanning applications.

  11. Non-linear optical measurements using a scanned, Bessel beam

    NASA Astrophysics Data System (ADS)

    Collier, Bradley B.; Awasthi, Samir; Lieu, Deborah K.; Chan, James W.

    2015-03-01

    Oftentimes cells are removed from the body for disease diagnosis or cellular research. This typically requires fluorescent labeling followed by sorting with a flow cytometer; however, possible disruption of cellular function or even cell death due to the presence of the label can occur. This may be acceptable for ex vivo applications, but as cells are more frequently moving from the lab to the body, label-free methods of cell sorting are needed to eliminate these issues. This is especially true of the growing field of stem cell research where specialized cells are needed for treatments. Because differentiation processes are not completely efficient, cells must be sorted to eliminate any unwanted cells (i.e. un-differentiated or differentiated into an unwanted cell type). In order to perform label-free measurements, non-linear optics (NLO) have been increasingly utilized for single cell analysis because of their ability to not disrupt cellular function. An optical system was developed for the measurement of NLO in a microfluidic channel similar to a flow cytometer. In order to improve the excitation efficiency of NLO, a scanned Bessel beam was utilized to create a light-sheet across the channel. The system was tested by monitoring twophoton fluorescence from polystyrene microbeads of different sizes. Fluorescence intensity obtained from light-sheet measurements were significantly greater than measurements made using a static Gaussian beam. In addition, the increase in intensity from larger sized beads was more evident for the light-sheet system.

  12. A method for estimation of accuracy of dose delivery with dynamic slit windows in medical linear accelerators.

    PubMed

    Ravichandran, R; Binukumar, J P; Sivakumar, S S; Krishnamurthy, K; Davis, C A

    2008-07-01

    Intensity-modulated radiotherapy (IMRT) clinical dose delivery is based on computer-controlled multileaf movements at different velocities. To test the accuracy of modulation of the beam periodically, quality assurance (QA) methods are necessary. Using a cylindrical phantom, dose delivery was checked at a constant geometry for sweeping fields. Repeated measurements with an in-house designed methodology over a period of 1 year indicate that the method is very sensitive to check the proper functioning of such dose delivery in medical linacs. A cylindrical perspex phantom with facility to accurately position a 0.6-cc (FC 65) ion chamber at constant depth at isocenter, (SA 24 constancy check tool phantom for MU check, Scanditronix Wellhofer) was used. Dosimeter readings were integrated for 4-mm, 10-mm, 20-mm sweeping fields and for 3 angular positions of the gantry periodically. Consistency of standard sweeping field output (10-mm slit width) and the ratios of outputs against other slit widths over a long period were reported. A 10-mm sweeping field output was found reproducible within an accuracy of 0.03% (n = 25) over 1 year. Four-millimeter, 20-mm outputs expressed as ratio with respect to 10-mm sweep output remained within a mean deviation of 0.2% and 0.03% respectively. Outputs at 3 gantry angles remained within 0.5%, showing that the effect of dynamic movements of multileaf collimator (MLC) on the output is minimal for angular positions of gantry. This method of QA is very simple and is recommended in addition to individual patient QA measurements, which reflect the accuracy of dose planning system. In addition to standard output and energy checks of linacs, the above measurements can be complemented so as to check proper functioning of multileaf collimator for dynamic field dose delivery.

  13. Huffman and linear scanning methods with statistical language models.

    PubMed

    Roark, Brian; Fried-Oken, Melanie; Gibbons, Chris

    2015-03-01

    Current scanning access methods for text generation in AAC devices are limited to relatively few options, most notably row/column variations within a matrix. We present Huffman scanning, a new method for applying statistical language models to binary-switch, static-grid typing AAC interfaces, and compare it to other scanning options under a variety of conditions. We present results for 16 adults without disabilities and one 36-year-old man with locked-in syndrome who presents with complex communication needs and uses AAC scanning devices for writing. Huffman scanning with a statistical language model yielded significant typing speedups for the 16 participants without disabilities versus any of the other methods tested, including two row/column scanning methods. A similar pattern of results was found with the individual with locked-in syndrome. Interestingly, faster typing speeds were obtained with Huffman scanning using a more leisurely scan rate than relatively fast individually calibrated scan rates. Overall, the results reported here demonstrate great promise for the usability of Huffman scanning as a faster alternative to row/column scanning.

  14. Huffman and linear scanning methods with statistical language models.

    PubMed

    Roark, Brian; Fried-Oken, Melanie; Gibbons, Chris

    2015-03-01

    Current scanning access methods for text generation in AAC devices are limited to relatively few options, most notably row/column variations within a matrix. We present Huffman scanning, a new method for applying statistical language models to binary-switch, static-grid typing AAC interfaces, and compare it to other scanning options under a variety of conditions. We present results for 16 adults without disabilities and one 36-year-old man with locked-in syndrome who presents with complex communication needs and uses AAC scanning devices for writing. Huffman scanning with a statistical language model yielded significant typing speedups for the 16 participants without disabilities versus any of the other methods tested, including two row/column scanning methods. A similar pattern of results was found with the individual with locked-in syndrome. Interestingly, faster typing speeds were obtained with Huffman scanning using a more leisurely scan rate than relatively fast individually calibrated scan rates. Overall, the results reported here demonstrate great promise for the usability of Huffman scanning as a faster alternative to row/column scanning. PMID:25672825

  15. Day to Day Clinically Relevant Corneal Elevation, Thickness, and Curvature Parameters Using the Orbscan II Scanning Slit Topographer and the Pentacam Scheimpflug Imaging Device

    PubMed Central

    Hashemi, Hassan; Mehravaran, Shiva

    2010-01-01

    The introduction of different techniques and computerized devices into clinical ophthalmology has significantly improved our knowledge of the eyes, optics, and eye conditions. Today, corneal topography is performed with a wide range of devices that implement a variety of techniques. Advance computerized analysis systems provide us with simple and quick evaluation procedures, yet the sophisticated data and clinical information that is generated can only be interpreted with adequate knowledge of the system itself as well as the accepted normal ranges of various properties assessed with these systems. Two computerized topography systems that are in common use are the Orbscan (Bausch and Lomb Inc., Rochester, NY, USA) and the Pentacam (Oculus GmBH, Wetzlar, Germany). The Orbscan is a slit-scanning device and the Pentacam is Scheimpflug imaging device. In this review, we present a brief description of both technologies, the techniques implemented in each device and the acquisition process with each. This will be followed by a list of corneal parameters that need to be assessed in screening patients for refractive surgery. We will discuss how these parameters are displayed, how each parameter may serve as clinic criteria, and how data should be interpreted. We will also try to provide evidence regarding the accuracy of different measurements, and the comparability of the two devices. PMID:20543936

  16. Optical sensors with MEMS, slit masks, and micromechanical devices

    NASA Astrophysics Data System (ADS)

    Riesenberg, Rainer; Wuttig, Andreas

    2001-10-01

    Concepts to increase the performance of optical sensors by combination with optical MEMS are discussed. Architectures of subsystems are reviewed, which modulate or switch the amplitude of the light by scanning, multiplexing and selecting interesting signal components (multi-object-mode). Arrangements with MEMS for optical sensors and instruments can decrease the pixel size and increase their number by creating virtual pixels. A number of signal components can be detected with a smaller number of detectors (detector pixels) by scanning. If the scanning is substituted by multiplexing the best efficiency is achieved. The measurement time can be reduced by selecting interesting objects or signal components to be detected. Architectures which combine single sensors, linear sensor arrays or two dimensional detector arrays with MEMS, slit masks, and micro-mechanical devices are discussed. Such devices are micro-mirrors, micro-shutters, the slit positioning system, the fibre positioning system, and other optical switches.

  17. Near-field light focusing by a slit array in a planar metal film with nonuniform slit dielectric material

    NASA Astrophysics Data System (ADS)

    David Wellems, L.; Huang, Danhong

    2012-02-01

    We study the interference of evanescent electromagnetic waves generated from multi-slits in a metal film and demonstrate the anomalous bending of light at infrared frequencies due to negative refraction. We also calculate the diffraction of an incident plane electromagnetic waves by a metallic film with an arbitrary linear array of slits, slit separation, and slit dielectric material. In contrast to a double-convex shaped quartz lens, we show that a planar metallic film with a one-dimensional slit array can also focus polarized light in the near-field region when either the slit width or the slit dielectric material becomes spatially nonuniform.

  18. Image distortion and its correction in linear galvanometric mirrors-based laser-scanning microscopy

    NASA Astrophysics Data System (ADS)

    Wang, Wenbo; Wu, Zhenguo; Zeng, Haishan

    2015-05-01

    To simplify imaging focusing and calibration tasks, a laser-scanning microscope needs to scan at a moderate frame rate. The inertia of a galvanometric scanner leads to time delays when following external commands, which subsequently introduces image distortions that deteriorate as scan frequency increases. Sinusoidal and triangular waveforms were examined as fast axis driving patterns. The interplay among driving pattern, frequency, sampling rate, phase shift, linear scanning range, and their effect on reconstructed images was discussed. Utilizing position feedback from the linear galvo scanners, the effect of response time could be automatically compensated in real time. Precompensated triangular driving waveform offered the least amount of image distortion.

  19. Image distortion and its correction in linear galvanometric mirrors-based laser-scanning microscopy.

    PubMed

    Wang, Wenbo; Wu, Zhenguo; Zeng, Haishan

    2015-05-01

    To simplify imaging focusing and calibration tasks, a laser-scanning microscope needs to scan ata moderate frame rate. The inertia of a galvanometric scanner leads to time delays when following external commands, which subsequently introduces image distortions that deteriorate as scan frequency increases. Sinusoidal and triangular waveforms were examined as fast axis driving patterns. The interplay among driving pattern, frequency, sampling rate, phase shift, linear scanning range, and their effect on reconstructed images was discussed. Utilizing position feedback from the linear galvo scanners, the effect of response time could be automatically compensated in real time. Precompensated triangular driving waveform offered the least amount of image distortion.

  20. Femoral neck anteversion measurement using linear slot scanning radiography.

    PubMed

    Chimhundu, Chipo; Sivarasu, Sudesh; Steiner, Stefan; Smit, Julian; Douglas, Tania S

    2016-02-01

    Measurements between anatomical landmarks on radiographs are useful for diagnosis and treatment planning in the orthopedic field. Direct measurement on single radiographic images, however, does not truly reflect spatial relationships, as depth information is lost. We used stereo images from a slot scanning X-ray machine to estimate coordinates of three-dimensional (3D) bony landmarks for femoral neck anteversion (FNA) measurement. A set of 7 landmarks consisting of the centre of the femoral head; the centre of the base of the femoral neck; the medial and lateral condyles; the medial and lateral posterior condyles; and finally the centre of the knee; were found to be identifiable and suitable for radiographic measurement. The reconstructed 3D coordinates were then used to define the 3D geometry of the anatomical axes required to estimate FNA. Stereophotogrammetric measurements on a sample of 30 dry right adult femurs were compared to reference values obtained using the Kingsley Olmstead method applied to photographic images. A strong positive correlation (0.998) was found and the mean ± standard deviation of the stereophotogrammetric approach (13.08 ± 6.87)° was comparable to that of the Kingsley Olmstead method (13.14 ± 6.88)°. Intra- and inter-observer reliability were high, with the lower bound of the 95% confidence interval above 0.98 for the intra-class correlation coefficient. The results merit further validation against three dimensional imaging technology such as computed tomography, to confirm stereophotogrammetry as a suitable alternative for FNA measurement. PMID:26776374

  1. Angle extended linear MEMS scanning system for 3D laser vision sensor

    NASA Astrophysics Data System (ADS)

    Pang, Yajun; Zhang, Yinxin; Yang, Huaidong; Zhu, Pan; Gai, Ye; Zhao, Jian; Huang, Zhanhua

    2016-09-01

    Scanning system is often considered as the most important part for 3D laser vision sensor. In this paper, we propose a method for the optical system design of angle extended linear MEMS scanning system, which has features of huge scanning degree, small beam divergence angle and small spot size for 3D laser vision sensor. The principle of design and theoretical formulas are derived strictly. With the help of software ZEMAX, a linear scanning optical system based on MEMS has been designed. Results show that the designed system can extend scanning angle from ±8° to ±26.5° with a divergence angle small than 3.5 mr, and the spot size is reduced for 4.545 times.

  2. Slit-Robo signaling.

    PubMed

    Blockus, Heike; Chédotal, Alain

    2016-09-01

    Slits are secreted proteins that bind to Roundabout (Robo) receptors. Slit-Robo signaling is best known for mediating axon repulsion in the developing nervous system. However, in recent years the functional repertoire of Slits and Robo has expanded tremendously and Slit-Robo signaling has been linked to roles in neurogenesis, angiogenesis and cancer progression among other processes. Likewise, our mechanistic understanding of Slit-Robo signaling has progressed enormously. Here, we summarize new insights into Slit-Robo evolutionary and system-dependent diversity, receptor-ligand interactions, signaling crosstalk and receptor activation. PMID:27578174

  3. Real-time prompt γ monitoring in spot-scanning proton therapy using imaging through a knife-edge-shaped slit.

    PubMed

    Bom, Victor; Joulaeizadeh, Leila; Beekman, Freek

    2012-01-21

    In this paper we report on Monte Carlo simulations to investigate real-time monitoring of the track depth profile in particle therapy by measuring prompt gamma ray emissions: a high sensitivity imaging system employing a knife-edge-shaped slit combined with a position-sensitive gamma detector was evaluated. Calculations to test this new concept were performed for a head-sized software phantom. Clear spatial correlation is shown between the distribution of gamma rays detected with energies above 1.5 MeV and the distribution of prompt gamma rays emitted from the phantom. The number of neutrons originating from nuclear reactions in the phantom that are detected at these high energies is small. Most importantly it is shown that under common therapy conditions enough data may be collected during one spot-step (of the order of 10 ms) to locate the distal dose edge with a 1σ accuracy of better than 1 mm. This indicates that simple slit cameras have high potential for accurate real-time particle therapy adjustment and may become a practical way to improve particle therapy accuracy.

  4. Breadboard linear array scan imager using LSI solid-state technology

    NASA Technical Reports Server (NTRS)

    Tracy, R. A.; Brennan, J. A.; Frankel, D. G.; Noll, R. E.

    1976-01-01

    The performance of large scale integration photodiode arrays in a linear array scan (pushbroom) breadboard was evaluated for application to multispectral remote sensing of the earth's resources. The technical approach, implementation, and test results of the program are described. Several self scanned linear array visible photodetector focal plane arrays were fabricated and evaluated in an optical bench configuration. A 1728-detector array operating in four bands (0.5 - 1.1 micrometer) was evaluated for noise, spectral response, dynamic range, crosstalk, MTF, noise equivalent irradiance, linearity, and image quality. Other results include image artifact data, temporal characteristics, radiometric accuracy, calibration experience, chip alignment, and array fabrication experience. Special studies and experimentation were included in long array fabrication and real-time image processing for low-cost ground stations, including the use of computer image processing. High quality images were produced and all objectives of the program were attained.

  5. Product ion scanning using a Q-q-Q linear ion trap (Q TRAP) mass spectrometer.

    PubMed

    Hager, James W; Yves Le Blanc, J C

    2003-01-01

    The use of a Q-q-Q(linear ion trap) instrument to obtain product ion spectra is described. The instrument is based on the ion path of a triple quadrupole mass spectrometer with Q3 operable as either a conventional RF/DC quadrupole mass filter or a linear ion trap mass spectrometer with axial ion ejection. This unique ion optical arrangement allows de-coupling of precursor ion isolation and fragmentation from the ion trap itself. The result is a high sensitivity tandem mass spectrometer with triple quadrupole fragmentation patterns and no inherent low mass cut-off. The use of the entrance RF-only section of the instrument as accumulation ion trap while the linear ion trap mass spectrometer is scanning enhances duty cycles and results in increased sensitivities by as much as a factor of 20. The instrument is also capable of all of the triple quadrupole scans including multiple-reaction monitoring (MRM) as well as precursor and constant neutral loss scanning. The high product ion scanning sensitivity allows the recording of useful product ion spectra near the MRM limit of quantitation.

  6. Handheld Thermoacoustic Scanning System Based on a Linear-array Transducer.

    PubMed

    Ji, Zhong; Ding, Wenzheng; Ye, Fanghao; Lou, Cunguang

    2016-07-01

    To receive the information necessary for imaging, traditional microwave-induced thermoacoustic imaging systems (MITISs) use a type of circular-scanning mode using single or arc detectors. However, the use of MITISs for body scanning is complicated by restrictions in space and imaging time. A linear-array detector, the most widely used transducer in medical ultrasound imaging systems for body scanning, is a possible alternative to MITISs for scanning biological tissues, such as from the breast or limbs. In this paper, a handheld MITIS, based on a linear-array detector and a multiple data acquisition system, is described, and the capacity of the system is explored experimentally. First, the vertical and lateral resolution of the system is discussed. Next, real-time imaging of a moving object, obtained with an image capture rate of 20 frame/s, is described. Finally, a phantom experiment is detailed, investigating the overall imaging capability. The results show that this system achieves rapid scanning with a large field of view. The system has the obvious advantages of being handheld, not using coupled fluids, and achieving real-time imaging with a large field of view, which make this MITIS more suitable for clinical applications.

  7. Handheld Thermoacoustic Scanning System Based on a Linear-array Transducer.

    PubMed

    Ji, Zhong; Ding, Wenzheng; Ye, Fanghao; Lou, Cunguang

    2016-07-01

    To receive the information necessary for imaging, traditional microwave-induced thermoacoustic imaging systems (MITISs) use a type of circular-scanning mode using single or arc detectors. However, the use of MITISs for body scanning is complicated by restrictions in space and imaging time. A linear-array detector, the most widely used transducer in medical ultrasound imaging systems for body scanning, is a possible alternative to MITISs for scanning biological tissues, such as from the breast or limbs. In this paper, a handheld MITIS, based on a linear-array detector and a multiple data acquisition system, is described, and the capacity of the system is explored experimentally. First, the vertical and lateral resolution of the system is discussed. Next, real-time imaging of a moving object, obtained with an image capture rate of 20 frame/s, is described. Finally, a phantom experiment is detailed, investigating the overall imaging capability. The results show that this system achieves rapid scanning with a large field of view. The system has the obvious advantages of being handheld, not using coupled fluids, and achieving real-time imaging with a large field of view, which make this MITIS more suitable for clinical applications. PMID:26294659

  8. Quantitative scanning probe microscope topographies by charge linearization of the vertical actuator.

    PubMed

    Fleming, Andrew J

    2010-10-01

    Many forms of scanning probe microscopy require a piezoelectric actuator to vary the probe-sample distance. Examples include constant-force atomic force microscopy and constant-current scanning tunneling microscopy. In such modes, the topography of the sample is reconstructed from the voltage applied to the vertical piezoelectric actuator. However, piezoelectric actuators exhibit significant hysteresis which can produce up to 14% uncertainty in the reproduced topography. In this work, a charge drive is used to linearize the vertical piezoelectric actuator which reduces the error from 14% to 0.65%.

  9. Non-Linear Structural Dynamics Characterization using a Scanning Laser Vibrometer

    NASA Technical Reports Server (NTRS)

    Pai, P. F.; Lee, S.-Y.

    2003-01-01

    This paper presents the use of a scanning laser vibrometer and a signal decomposition method to characterize non-linear dynamics of highly flexible structures. A Polytec PI PSV-200 scanning laser vibrometer is used to measure transverse velocities of points on a structure subjected to a harmonic excitation. Velocity profiles at different times are constructed using the measured velocities, and then each velocity profile is decomposed using the first four linear mode shapes and a least-squares curve-fitting method. From the variations of the obtained modal \\ielocities with time we search for possible non-linear phenomena. A cantilevered titanium alloy beam subjected to harmonic base-excitations around the second. third, and fourth natural frequencies are examined in detail. Influences of the fixture mass. gravity. mass centers of mode shapes. and non-linearities are evaluated. Geometrically exact equations governing the planar, harmonic large-amplitude vibrations of beams are solved for operational deflection shapes using the multiple shooting method. Experimental results show the existence of 1:3 and 1:2:3 external and internal resonances. energy transfer from high-frequency modes to the first mode. and amplitude- and phase- modulation among several modes. Moreover, the existence of non-linear normal modes is found to be questionable.

  10. Scanning differential polarization microscope: Its use to image linear and circular differential scattering

    SciTech Connect

    Mickols, W.; Maestre, M.F.

    1988-06-01

    A differential polarization microscope that couples the sensitivity of single-beam measurement of circular dichroism and circular differential scattering with the simultaneous measurement of linear dichroism and linear differential scattering has been developed. The microscope uses a scanning microscope stage and single-point illumination to give the very shallow depth of field found in confocal microscopy. This microscope can operate in the confocal mode as well as in the near confocal condition that can allow one to program the coherence and spatial resolution of the microscope. This microscope has been used to study the change in the structure of chromatin during the development of sperm in Drosophila.

  11. The Nested High Voltage Generator and Linear Scanning for Security Inspection

    SciTech Connect

    Adler, R. J.; Montoya, T.B.; Richter-Sand, R.J.; Annis, M.; Vellasco, G.; Wildfeur, J.

    2003-08-26

    Scanning electron beams and X-ray producing electron beams over large areas is critical in a number of technical areas. We have combined a Nested High Voltage Generator (NHVG) operating at 1.15 MeV, a linear scanning system as originally proposed by Cleland, and a new collimator design to create a unique system for producing transmission and backscatter X-Ray images. The NHVG is a DC accelerator with features of low ripple and efficient operation at medium power and it is used in this equipment. Images can be produced through 4 - 5 inches of steel, and backscatter images can also be produced. The scanning system is uniquely small, and it is capable of producing uniform irradiation over large volumes. We will describe the equipment and its performance.

  12. A novel method of drift-scanning stars suppression based on the standardized linear filter

    NASA Astrophysics Data System (ADS)

    Lin, Jianlin; Ping, Xijian; Hou, Guanghua; Ma, Debao

    2011-11-01

    A large number of stars in the drift-scanning star image have interfered with the detection of small target, this paper proposes an adaptive linear filtering method to achieve the small target detection by suppressing the stars. Firstly, the characteristics of stars, interest target and noise three different representative objects in the star image are analyzed, then the standardized linear filter is constructed to suppress the stars. For the purpose of decreasing the influence region of stars filtering uniformly, a gradient linear filter is constructed to modify the stars suppression method with the standardized linear filter. Then the filter parameter selection method is given. Finally, a multi-frame target track experiment on the real drift-scanning data is made to testify the validity of the proposed method. With the processing results of different methods, it has been showed that the proposed method for suppressing stars with different length and lean angle has a better effect, higher robustness and easier application than the others.

  13. Slit Wheel Repeatability

    NASA Astrophysics Data System (ADS)

    DiFelice, Audrey

    2012-10-01

    Test the repeatibility of the slit wheel by taking a sequence of comparison lamp spectra with grating G230MB {2697} and the three smallest long slits {52X0.2, 52X0.1, and 52X0.05}. This is a clone of Cycle 19 Program 12771.

  14. Slit Wheel Repeatability

    NASA Astrophysics Data System (ADS)

    Long, Chris

    2011-10-01

    Test the repeatibility of the slit wheel by taking a sequence of comparison lamp spectra with grating G230MB {2697} and the three smallest long slits {52X0.2, 52X0.1, and 52X0.05}. This is a clone of Cycle 18 Program 12410.

  15. Slit Wheel Repeatability

    NASA Astrophysics Data System (ADS)

    DiFelice, Audrey

    2013-10-01

    Test the repeatibility of the slit wheel by taking a sequence of comparison lamp spectra with grating G230MB {2697} and the three smallest long slits {52X0.2, 52X0.1, and 52X0.05}. This is a clone of Cycle 20 Program 13140.

  16. Slit Wheel Repeatability

    NASA Astrophysics Data System (ADS)

    Zheng, Wei

    2010-09-01

    Test the repeatibility of the slit wheel by taking a sequence of comparison lamp spectra with grating G230MB {2697} and the three smallest long slits {52X0.2, 52X0.1, and 52X0.05}. This is a clone of Cycle 17 Program 11851.

  17. Edge guided image reconstruction in linear scan CT by weighted alternating direction TV minimization.

    PubMed

    Cai, Ailong; Wang, Linyuan; Zhang, Hanming; Yan, Bin; Li, Lei; Xi, Xiaoqi; Li, Jianxin

    2014-01-01

    Linear scan computed tomography (CT) is a promising imaging configuration with high scanning efficiency while the data set is under-sampled and angularly limited for which high quality image reconstruction is challenging. In this work, an edge guided total variation minimization reconstruction (EGTVM) algorithm is developed in dealing with this problem. The proposed method is modeled on the combination of total variation (TV) regularization and iterative edge detection strategy. In the proposed method, the edge weights of intermediate reconstructions are incorporated into the TV objective function. The optimization is efficiently solved by applying alternating direction method of multipliers. A prudential and conservative edge detection strategy proposed in this paper can obtain the true edges while restricting the errors within an acceptable degree. Based on the comparison on both simulation studies and real CT data set reconstructions, EGTVM provides comparable or even better quality compared to the non-edge guided reconstruction and adaptive steepest descent-projection onto convex sets method. With the utilization of weighted alternating direction TV minimization and edge detection, EGTVM achieves fast and robust convergence and reconstructs high quality image when applied in linear scan CT with under-sampled data set.

  18. Relating Linear and Volumetric Variables Through Body Scanning to Improve Human Interfaces in Space

    NASA Technical Reports Server (NTRS)

    Margerum, Sarah E.; Ferrer, Mike A.; Young, Karen S.; Rajulu, Sudhakar

    2010-01-01

    Designing space suits and vehicles for the diverse human population present unique challenges for the methods of traditional anthropometry. Space suits are bulky and allow the operator to shift position within the suit and inhibit the ability to identify body landmarks. Limited suit sizing options also cause variability in fit and performance between similarly sized individuals. Space vehicles are restrictive in volume in both the fit and the ability to collect data. NASA's Anthropometric and Biomechanics Facility (ABF) has utilized 3D scanning to shift from traditional linear anthropometry to explore and examine volumetric capabilities to provide anthropometric solutions for design. Overall, the key goals are to improve the human-system performance and develop new processes to aid in the design and evaluation of space systems. Four case studies are presented that illustrate the shift from purely linear analyses to an augmented volumetric toolset to predict and analyze the human within the space suit and vehicle. The first case study involves the calculation of maximal head volume to estimate total free volume in the helmet for proper air exchange. Traditional linear measurements resulted in an inaccurate representation of the head shape, yet limited data exists for the determination of a large head volume. Steps were first taken to identify and classify a maximum head volume and the resulting comparisons to the estimate are presented in this paper. This study illustrates the gap between linear components of anthropometry and the need for overall volume metrics in order to provide solutions. A second case study examines the overlay of the space suit scans and components onto scanned individuals to quantify fit and clearance to aid in sizing the suit to the individual. Restrictions in space suit size availability present unique challenges to optimally fit the individual within a limited sizing range while maintaining performance. Quantification of the clearance and

  19. Slit injection device

    DOEpatents

    Alger, Terry W.; Schlitt, Leland G.; Bradley, Laird P.

    1976-06-15

    A laser cavity electron beam injection device provided with a single elongated slit window for passing a suitably shaped electron beam and means for varying the current density of the injected electron beam.

  20. High-sensitive thermal video camera with self-scanned 128 InSb linear array

    NASA Astrophysics Data System (ADS)

    Fujisada, Hiroyuki

    1991-12-01

    A compact thermal video camera with very high sensitivity has been developed by using a self-scanned 128 InSb linear array photodiode. Two-dimensional images are formed by a self- scanning function of the linear array focal plane assembly in the horizontal direction and by a vibration mirror in the vertical direction. Images with 128 X 128 pixel number are obtained every 1/30 seconds. A small size InSb detector array with a total length of 7.68 mm is utilized in order to build the compact system. In addition, special consideration is given to a configuration of optics, vibration mirror, and focal plane assembly. Real-time signal processing by a microprocessor is carried out to compensate inhomogeneous sensitivities and irradiances for each detector. The standard NTSC TV format is employed for output video signals. The thermal video camera developed had a very high radiometric sensitivity. Minimum resolvable temperature difference (MRTD) is estimated at about 0.02 K for 300 K target. The stable operation is possible without blackbody reference, because of very small stray radiation.

  1. SCAN+

    SciTech Connect

    Kenneth Krebs, John Svoboda

    2009-11-01

    SCAN+ is a software application specifically designed to control the positioning of a gamma spectrometer by a two dimensional translation system above spent fuel bundles located in a sealed spent fuel cask. The gamma spectrometer collects gamma spectrum information for the purpose of spent fuel cask fuel loading verification. SCAN+ performs manual and automatic gamma spectrometer positioning functions as-well-as exercising control of the gamma spectrometer data acquisitioning functions. Cask configuration files are used to determine the positions of spent fuel bundles. Cask scanning files are used to determine the desired scan paths for scanning a spent fuel cask allowing for automatic unattended cask scanning that may take several hours.

  2. The fundus slit lamp.

    PubMed

    Gellrich, Marcus-Matthias

    2015-01-01

    Fundus biomicroscopy with the slit lamp as it is practiced widely nowadays was not established until the 1980-es with the introduction of the Volk lenses +90 and +60D. Thereafter little progress has been made in retinal imaging with the slit lamp. It is the aim of this paper to fully exploit the potential of a video slit lamp for fundus documentation by using easily accessible additions. Suitable still images are easily retrieved from videorecordings of slit lamp examinations. The effects of changements in the slit lamp itself (slit beam and apertures) and its examination equipment (converging lenses from +40 to +90D) on quality and spectrum of fundus images are demonstrated. Imaging software is applied for reconstruction of larger fundus areas in a mosaic pattern (Hugin®) and to perform the flicker test in order to visualize changes in the same fundus area at different points of time (Power Point®). The three lenses +90/+60/+40D are a good choice for imaging the whole spectrum of retinal diseases. Displacement of the oblique slit light can be used to assess changes in the surface profile of the inner retina which occurs e.g. in macular holes or pigment epithelial detachment. The mosaic function in its easiest form (one strip macula adapted to one strip with the optic disc) provides an overview of the posterior pole comparable to a fundus camera's image. A reconstruction of larger fundus areas is feasible for imaging in vitreoretinal surgery or occlusive vessel disease. The flicker test is a fine tool for monitoring progressive glaucoma by changes in the optic disc, and it is also a valuable diagnostic tool in macular disease. Nearly all retinal diseases can be imaged with the slit lamp - irrespective whether they affect the posterior pole, mainly the optic nerve or the macula, the whole retina or only its periphery. Even a basic fundus controlled perimetry is possible. Therefore fundus videography with the slit lamp is a worthwhile approach especially for the

  3. A matterless double slit

    NASA Astrophysics Data System (ADS)

    King, Ben; di Piazza, Antonino; Keitel, Christoph H.

    2010-02-01

    Double slits provide incoming particles with a choice. Those that survive passage through the slits have chosen from two possible paths, which interfere to distribute them in a wave-like manner. Such wave-particle duality continues to be challenged and investigated in a broad range of disciplines with electrons, neutrons, helium atoms, C60 fullerenes, Bose-Einstein condensates and biological molecules. All variants have hitherto involved material constituents. We present a matterless double-slit scenario in which photons generated from virtual electron-positron pair annihilation in head-on collisions of a probe laser field with two ultra-intense laser beams form a double-slit interference pattern. Such electromagnetic fields are predicted to induce material-like behaviour in vacuum, supporting elastic scattering between photons. Our double-slit scenario presents, on the one hand, a realizable method with which to observe photon-photon scattering and, on the other hand, demonstrates the possibility of both controlling light with light and non-locally investigating features of the quantum vacuum structure.

  4. In situ azimuthal rotation device for linear dichroism measurements in scanning transmission x-ray microscopy

    NASA Astrophysics Data System (ADS)

    Hernández-Cruz, D.; Hitchcock, A. P.; Tyliszczak, T.; Rousseau, M.-E.; Pézolet, M.

    2007-03-01

    A novel miniature rotation device used in conjunction with a scanning transmission x-ray microscope is described. It provides convenient in situ sample rotation to enable measurements of linear dichroism at high spatial resolution. The design, fabrication, and mechanical characterization are presented. This device has been used to generate quantitative maps of the spatial distribution of the orientation of proteins in several different spider and silkworm silks. Specifically, quantitative maps of the dichroic signal at the C 1s→π*amide transition in longitudinal sections of the silk fibers give information about the spatial orientation, degree of alignment, and spatial distribution of protein peptide bonds. A new approach for analyzing the dichroic signal to extract orientation distributions, in addition to magnitudes of aligned components, is presented and illustrated with results from Nephila clavipes dragline spider silk measured using the in situ rotation device.

  5. Efficient linear phase contrast in scanning transmission electron microscopy with matched illumination and detector interferometry

    NASA Astrophysics Data System (ADS)

    Ophus, Colin; Ciston, Jim; Pierce, Jordan; Harvey, Tyler R.; Chess, Jordan; McMorran, Benjamin J.; Czarnik, Cory; Rose, Harald H.; Ercius, Peter

    2016-02-01

    The ability to image light elements in soft matter at atomic resolution enables unprecedented insight into the structure and properties of molecular heterostructures and beam-sensitive nanomaterials. In this study, we introduce a scanning transmission electron microscopy technique combining a pre-specimen phase plate designed to produce a probe with structured phase with a high-speed direct electron detector to generate nearly linear contrast images with high efficiency. We demonstrate this method by using both experiment and simulation to simultaneously image the atomic-scale structure of weakly scattering amorphous carbon and strongly scattering gold nanoparticles. Our method demonstrates strong contrast for both materials, making it a promising candidate for structural determination of heterogeneous soft/hard matter samples even at low electron doses comparable to traditional phase-contrast transmission electron microscopy. Simulated images demonstrate the extension of this technique to the challenging problem of structural determination of biological material at the surface of inorganic crystals.

  6. Efficient linear phase contrast in scanning transmission electron microscopy with matched illumination and detector interferometry.

    PubMed

    Ophus, Colin; Ciston, Jim; Pierce, Jordan; Harvey, Tyler R; Chess, Jordan; McMorran, Benjamin J; Czarnik, Cory; Rose, Harald H; Ercius, Peter

    2016-01-01

    The ability to image light elements in soft matter at atomic resolution enables unprecedented insight into the structure and properties of molecular heterostructures and beam-sensitive nanomaterials. In this study, we introduce a scanning transmission electron microscopy technique combining a pre-specimen phase plate designed to produce a probe with structured phase with a high-speed direct electron detector to generate nearly linear contrast images with high efficiency. We demonstrate this method by using both experiment and simulation to simultaneously image the atomic-scale structure of weakly scattering amorphous carbon and strongly scattering gold nanoparticles. Our method demonstrates strong contrast for both materials, making it a promising candidate for structural determination of heterogeneous soft/hard matter samples even at low electron doses comparable to traditional phase-contrast transmission electron microscopy. Simulated images demonstrate the extension of this technique to the challenging problem of structural determination of biological material at the surface of inorganic crystals. PMID:26923483

  7. Efficient linear phase contrast in scanning transmission electron microscopy with matched illumination and detector interferometry

    PubMed Central

    Ophus, Colin; Ciston, Jim; Pierce, Jordan; Harvey, Tyler R.; Chess, Jordan; McMorran, Benjamin J.; Czarnik, Cory; Rose, Harald H.; Ercius, Peter

    2016-01-01

    The ability to image light elements in soft matter at atomic resolution enables unprecedented insight into the structure and properties of molecular heterostructures and beam-sensitive nanomaterials. In this study, we introduce a scanning transmission electron microscopy technique combining a pre-specimen phase plate designed to produce a probe with structured phase with a high-speed direct electron detector to generate nearly linear contrast images with high efficiency. We demonstrate this method by using both experiment and simulation to simultaneously image the atomic-scale structure of weakly scattering amorphous carbon and strongly scattering gold nanoparticles. Our method demonstrates strong contrast for both materials, making it a promising candidate for structural determination of heterogeneous soft/hard matter samples even at low electron doses comparable to traditional phase-contrast transmission electron microscopy. Simulated images demonstrate the extension of this technique to the challenging problem of structural determination of biological material at the surface of inorganic crystals. PMID:26923483

  8. Efficient linear phase contrast in scanning transmission electron microscopy with matched illumination and detector interferometry.

    PubMed

    Ophus, Colin; Ciston, Jim; Pierce, Jordan; Harvey, Tyler R; Chess, Jordan; McMorran, Benjamin J; Czarnik, Cory; Rose, Harald H; Ercius, Peter

    2016-02-29

    The ability to image light elements in soft matter at atomic resolution enables unprecedented insight into the structure and properties of molecular heterostructures and beam-sensitive nanomaterials. In this study, we introduce a scanning transmission electron microscopy technique combining a pre-specimen phase plate designed to produce a probe with structured phase with a high-speed direct electron detector to generate nearly linear contrast images with high efficiency. We demonstrate this method by using both experiment and simulation to simultaneously image the atomic-scale structure of weakly scattering amorphous carbon and strongly scattering gold nanoparticles. Our method demonstrates strong contrast for both materials, making it a promising candidate for structural determination of heterogeneous soft/hard matter samples even at low electron doses comparable to traditional phase-contrast transmission electron microscopy. Simulated images demonstrate the extension of this technique to the challenging problem of structural determination of biological material at the surface of inorganic crystals.

  9. SCAN+

    2009-11-01

    SCAN+ is a software application specifically designed to control the positioning of a gamma spectrometer by a two dimensional translation system above spent fuel bundles located in a sealed spent fuel cask. The gamma spectrometer collects gamma spectrum information for the purpose of spent fuel cask fuel loading verification. SCAN+ performs manual and automatic gamma spectrometer positioning functions as-well-as exercising control of the gamma spectrometer data acquisitioning functions. Cask configuration files are used to determinemore » the positions of spent fuel bundles. Cask scanning files are used to determine the desired scan paths for scanning a spent fuel cask allowing for automatic unattended cask scanning that may take several hours.« less

  10. 3-D ultrasonic strain imaging based on a linear scanning system.

    PubMed

    Huang, Qinghua; Xie, Bo; Ye, Pengfei; Chen, Zhaohong

    2015-02-01

    This paper introduces a 3-D strain imaging method based on a freehand linear scanning mode. We designed a linear sliding track with a position sensor and a height-adjustable holder to constrain the movement of an ultrasound probe in a freehand manner. When moving the probe along the sliding track, the corresponding positional measures for the probe are transmitted via a wireless communication module based on Bluetooth in real time. In a single examination, the probe is scanned in two sweeps in which the height of the probe is adjusted by the holder to collect the pre- and postcompression radio-frequency echoes, respectively. To generate a 3-D strain image, a volume cubic in which the voxels denote relative strains for tissues is defined according to the range of the two sweeps. With respect to the post-compression frames, several slices in the volume are determined and the pre-compression frames are re-sampled to precisely correspond to the post-compression frames. Thereby, a strain estimation method based on minimizing a cost function using dynamic programming is used to obtain the 2-D strain image for each pair of frames from the re-sampled pre-compression sweep and the post-compression sweep, respectively. A software system is developed for volume reconstruction, visualization, and measurement of the 3-D strain images. The experimental results show that high-quality 3-D strain images of phantom and human tissues can be generated by the proposed method, indicating that the proposed system can be applied for real clinical applications (e.g., musculoskeletal assessments).

  11. Filtration to reduce paediatric dose for a linear slot-scanning digital X-ray machine.

    PubMed

    Perks, T D; Dendere, R; Irving, B; Hartley, T; Scholtz, P; Lawson, A; Trauernicht, C; Steiner, S; Douglas, T S

    2015-12-01

    This paper describes modelling, application and validation of a filtration technique for a linear slot-scanning digital X-ray system to reduce radiation dose to paediatric patients while preserving diagnostic image quality. A dose prediction model was implemented, which calculates patient entrance doses using variable input parameters. Effective dose is calculated using a Monte Carlo simulation. An added filter of 1.8-mm aluminium was predicted to lower the radiation dose significantly. An objective image quality study was conducted using detective quantum efficiency (DQE). The PTW Normi 4FLU test phantom was used for quantitative assessment, showing that image contrast and spatial resolution were maintained with the proposed filter. A paediatric cadaver full-body imaging trial assessed the diagnostic quality of the images and measured the dose reduction using a 1.8-mm aluminium filter. Assessment by radiologists indicated that diagnostic quality was maintained with the added filtration, despite a reduction in DQE. A new filtration technique for full-body paediatric scanning on the Lodox Statscan has been validated, reducing entrance dose for paediatric patients by 36 % on average and effective dose by 27 % on average, while maintaining image quality. PMID:25433049

  12. SLIT ADJUSTMENT CLAMP

    DOEpatents

    McKenzie, K.R.

    1959-07-01

    An electrode support which permits accurate alignment and adjustment of the electrode in a plurality of planes and about a plurality of axes in a calutron is described. The support will align the slits in the electrode with the slits of an ionizing chamber so as to provide for the egress of ions. The support comprises an insulator, a leveling plate carried by the insulator and having diametrically opposed attaching screws screwed to the plate and the insulator and diametrically opposed adjusting screws for bearing against the insulator, and an electrode associated with the plate for adjustment therewith.

  13. Radiation energy transport through hydrodynamically evolving slits

    NASA Astrophysics Data System (ADS)

    Foster, J. M.; Graham, P.; Taylor, M.; Moore, A.; Sorce, C.; Reighard, A.; MacLaren, S.; Young, P.; Glendinning, G.; Blue, B.; Back, C.; Hund, J.

    2008-11-01

    Radiation transport through enclosed spaces with inwardly moving walls is a key component of the physics of laser-heated hohlraums. It arises in the cavity itself (where inward motion of the wall results in late-time stagnation of dense plasma on the hohlraum axis), and also in the laser-entry and diagnostic holes (where an understanding of hole-closure is important to hohlraum design and the interpretation of diagnostic data). To understand these phenomena better, we have carried out a series of experiments at the Omega laser facility. A laser-heated hohlraum is used to illuminate linear and annular slits machined in samples of solid-density tantalum and low-density, tantalum-oxide foam. Measurements of the transmitted energy are made indirectly (by measuring the temperature rise of a ``calorimeter'' hohlraum) and directly (by measuring the emission from the slit component, using a target in which the calorimeter hohlraum was omitted). The hydrodynamics is investigated by self-emission and absorption (backlighting) x-ray imaging of the closing slits. Simulations (using a 2-D Eulerian hydrocode) reproduce the overall energetics, the detail of the deceleration shock and axial stagnation region at the centre of the slit, and the complex shock interactions that occur at corners of the slits.

  14. CALUTRON ION SOURCE SLIT CLEANER

    DOEpatents

    Starr, A.M.

    1959-08-25

    >An apparatus is described for removing deposits from the beam forming slits of the source without affecting the vacuum. A scraper element having a configuration conforming to the cross section of the slit is posttioned therein, and linkage is provided for moving the scraper along the slit and for retracting the scraper to one end during normal operation.

  15. Top-level design and pilot analysis of low-end CT scanners based on linear scanning for developing countries.

    PubMed

    Liu, Fenglin; Yu, Hengyong; Cong, Wenxiang; Wang, Ge

    2014-01-01

    The goal is to develop new architectures for computed tomography (CT) which are at an ultra-low-cost for developing countries, especially in rural areas. The proposed general scheme is inspired by the recently developed compressive sensing and interior tomography techniques, where the data acquisition system targets a region of interest (ROI) to acquire limited and truncated data. Similar to linear tomosynthesis, the source and detector are translated in opposite directions but in contrast to conventional tomosynthesis, our proposal is for either ROI reconstruction with one or more localized linear scans or global reconstruction by combining multiple ROI reconstructions. In other words, the popular slip ring is replaced by a translation based setup, and the instrumentation cost is reduced by a relaxation of the imaging speed requirement. The various translational scanning modes are theoretically analyzed, and the scanning parameters are optimized. The numerical simulation results from different numbers of linear scans confirm the feasibility of the proposed scheme, and suggest two preferred low-end systems for horizontal and vertical patient positions respectively. Ultra-low-cost x-ray CT is feasible with our proposed combination of linear scanning, compressive sensing, and interior tomography. The proposed architecture can be tailored into permanent, movable, or reconfigurable systems as desirable. Advanced image registration and spectral imaging features can be included as well.

  16. On the stick-slip flow from slit and cylindrical dies of a Phan-Thien and Tanner fluid model. II. Linear stability analysis

    NASA Astrophysics Data System (ADS)

    Karapetsas, George; Tsamopoulos, John

    2013-09-01

    During extrusion of viscoelastic fluids various flow instabilities may arise resulting in a distorted free surface. In order to investigate the factors generating these instabilities we performed a linear stability analysis at zero Reynolds number around the steady solution of the cylindrical or planar stick-slip flow for a viscoelastic fluid following the affine exponential Phan-Thien Tanner (PTT) model. Stick-slip flow is an important special case of the extrudate swell problem, since the latter reduces to it in the limit of infinite surface tension but avoids the complications of a free-boundary flow. The linear stability analysis is performed for various values of the rheological parameters of the PTT model in order to determine the effects of all material properties. It is found that the flow becomes unstable as the Weissenberg number increases above a critical value, due to a Hopf bifurcation suggesting that the flow will become periodic in time. Both the critical value of the Weissenberg number and the frequency of the instability depend strongly on the rheological parameters of the viscoelastic model. The corresponding eigenvectors indicate that the perturbed flow field has a spatially periodic structure, initiated at the rim of the die, extending for up to 5-7 die gaps downstream, but confined close to the surface of the extrudate, in qualitative agreement with existing experiments. This suggests that instability is generated by the combination of the singularity in the velocity and stress fields at the die lip and the strong extension that the extruded polymer undergoes near its surface. The elasticity alone can be responsible for the appearance of instabilities in the extrusion process of viscoelastic fluids and the often used assumptions of wall slip or compressibility, although they might be present, are not required. Finally, the mechanisms that produce these instabilities are examined through energy analysis of the disturbance flow.

  17. Fourier-based reconstruction via alternating direction total variation minimization in linear scan CT

    NASA Astrophysics Data System (ADS)

    Cai, Ailong; Wang, Linyuan; Yan, Bin; Zhang, Hanming; Li, Lei; Xi, Xiaoqi; Li, Jianxin

    2015-03-01

    In this study, we consider a novel form of computed tomography (CT), that is, linear scan CT (LCT), which applies a straight line trajectory. Furthermore, an iterative algorithm is proposed for pseudo-polar Fourier reconstruction through total variation minimization (PPF-TVM). Considering that the sampled Fourier data are distributed in pseudo-polar coordinates, the reconstruction model minimizes the TV of the image subject to the constraint that the estimated 2D Fourier data for the image are consistent with the 1D Fourier transform of the projection data. PPF-TVM employs the alternating direction method (ADM) to develop a robust and efficient iteration scheme, which ensures stable convergence provided that appropriate parameter values are given. In the ADM scheme, PPF-TVM applies the pseudo-polar fast Fourier transform and its adjoint to iterate back and forth between the image and frequency domains. Thus, there is no interpolation in the Fourier domain, which makes the algorithm both fast and accurate. PPF-TVM is particularly useful for limited angle reconstruction in LCT and it appears to be robust against artifacts. The PPF-TVM algorithm was tested with the FORBILD head phantom and real data in comparisons with state-of-the-art algorithms. Simulation studies and real data verification suggest that PPF-TVM can reconstruct higher accuracy images with lower time consumption.

  18. Optimization of an adaptive SPECT system with the scanning linear estimator

    NASA Astrophysics Data System (ADS)

    Ghanbari, Nasrin; Clarkson, Eric; Kupinski, Matthew A.; Li, Xin

    2015-08-01

    The adaptive single-photon emission computed tomography (SPECT) system studied here acquires an initial scout image to obtain preliminary information about the object. Then the configuration is adjusted by selecting the size of the pinhole and the magnification that optimize system performance on an ensemble of virtual objects generated to be consistent with the scout data. In this study the object is a lumpy background that contains a Gaussian signal with a variable width and amplitude. The virtual objects in the ensemble are imaged by all of the available configurations and the subsequent images are evaluated with the scanning linear estimator to obtain an estimate of the signal width and amplitude. The ensemble mean squared error (EMSE) on the virtual ensemble between the estimated and the true parameters serves as the performance figure of merit for selecting the optimum configuration. The results indicate that variability in the original object background, noise and signal parameters leads to a specific optimum configuration in each case. A statistical study carried out for a number of objects show that the adaptive system on average performs better than its nonadaptive counterpart.

  19. Efficient linear phase contrast in scanning transmission electron microscopy with matched illumination and detector interferometry

    DOE PAGES

    Ophus, Colin; Ciston, Jim; Pierce, Jordan; Harvey, Tyler R.; Chess, Jordan; McMorran, Benjamin J.; Czarnik, Cory; Rose, Harald H.; Ercius, Peter

    2016-02-29

    The ability to image light elements in soft matter at atomic resolution enables unprecedented insight into the structure and properties of molecular heterostructures and beam-sensitive nanomaterials. In this study, we introduce a scanning transmission electron microscopy technique combining a pre-specimen phase plate designed to produce a probe with structured phase with a high-speed direct electron detector to generate nearly linear contrast images with high efficiency. We demonstrate this method by using both experiment and simulation to simultaneously image the atomic-scale structure of weakly scattering amorphous carbon and strongly scattering gold nanoparticles. Our method demonstrates strong contrast for both materials, makingmore » it a promising candidate for structural determination of heterogeneous soft/hard matter samples even at low electron doses comparable to traditional phase-contrast transmission electron microscopy. Ultimately, simulated images demonstrate the extension of this technique to the challenging problem of structural determination of biological material at the surface of inorganic crystals.« less

  20. Assessment of cardiac single-photon emission computed tomography performance using a scanning linear observer

    SciTech Connect

    Lee, Chih-Jie; Kupinski, Matthew A.; Volokh, Lana

    2013-01-15

    Purpose: Single-photon emission computed tomography (SPECT) is widely used to detect myocardial ischemia and myocardial infarction. It is important to assess and compare different SPECT system designs in order to achieve the highest detectability of cardiac defects. Methods: Whitaker et al.'s study ['Estimating random signal parameters from noisy images with nuisance parameters: linear and scanning-linear methods,' Opt. Express 16(11), 8150-8173 (2008)] on the scanning linear observer (SLO) shows that the SLO can be used to estimate the location and size of signals. One major advantage of the SLO is that it can be used with projection data rather than with reconstruction data. Thus, this observer model assesses the overall hardware performance independent of any reconstruction algorithm. In addition, the computation time of image quality studies is significantly reduced. In this study, three systems based on the design of the GE cadmium zinc telluride-based dedicated cardiac SPECT camera Discovery 530c were assessed. This design, which is officially named the Alcyone Technology: Discovery NM 530c, was commercialized in August, 2009. The three systems, GE27, GE19, and GE13, contain 27, 19, and 13 detectors, respectively. Clinically, a human heart can be virtually segmented into three coronary artery territories: the left-anterior descending artery, left-circumflex artery, and right coronary artery. One of the most important functions of a cardiac SPECT system is to produce images from which a radiologist can accurately predict in which territory the defect exists [http://www.asnc.org/media/PDFs/PPReporting081511.pdf, Guideline from American Society of Nuclear Cardiology]. A good estimation of the extent of the defect from the projection images is also very helpful for determining the seriousness of the myocardial ischemia. In this study, both the location and extent of defects were estimated by the SLO, and the system performance was assessed by localization

  1. Effect of linear alkyl benzene sulfonate in skin of fish fingerlings (Cirrhina mrigala): observations with scanning electron microscope

    SciTech Connect

    Misra, V.; Chawla, G.; Kumar, V.; Lal, H.; Viswanathan, P.N.

    1987-04-01

    Pathomorphological changes in the skin was noticed under the scanning electron microscope in fish fingerlings (Cirrhina mrigala) exposed to 0.005 ppm (25% of the LC50) concentration to linear alkyl benzene sulfonate. The epithelial cells present in the epidermis of the skin were found to secrete more mucus with linear alkyl benzene sulfonate (LAS) than did controls. The presence or deposition of mucus on the surface of skin indicated likely molecular interaction between constituents of mucus and LAS.

  2. Effect of linear alkyl benzene sulfonate in skin of fish fingerlings (Cirrhina mrigala): observations with scanning electron microscope.

    PubMed

    Misra, V; Chawla, G; Kumar, V; Lal, H; Viswanathan, P N

    1987-04-01

    Pathomorphological changes in the skin was noticed under the scanning electron microscope in fish fingerlings (Cirrhina mrigala) exposed to 0.005 ppm (25% of the LC50) concentration to linear alkyl benzene sulfonate. The epithelial cells present in the epidermis of the skin were found to secrete more mucus with linear alkyl benzene sulfonate (LAS) than did controls. The presence or deposition of mucus on the surface of skin indicated likely molecular interaction between constituents of mucus and LAS.

  3. Comparison of the scanning linear estimator (SLE) and ROI methods for quantitative SPECT imaging

    NASA Astrophysics Data System (ADS)

    Könik, Arda; Kupinski, Meredith; Hendrik Pretorius, P.; King, Michael A.; Barrett, Harrison H.

    2015-08-01

    In quantitative emission tomography, tumor activity is typically estimated from calculations on a region of interest (ROI) identified in the reconstructed slices. In these calculations, unpredictable bias arising from the null functions of the imaging system affects ROI estimates. The magnitude of this bias depends upon the tumor size and location. In prior work it has been shown that the scanning linear estimator (SLE), which operates on the raw projection data, is an unbiased estimator of activity when the size and location of the tumor are known. In this work, we performed analytic simulation of SPECT imaging with a parallel-hole medium-energy collimator. Distance-dependent system spatial resolution and non-uniform attenuation were included in the imaging simulation. We compared the task of activity estimation by the ROI and SLE methods for a range of tumor sizes (diameter: 1-3 cm) and activities (contrast ratio: 1-10) added to uniform and non-uniform liver backgrounds. Using the correct value for the tumor shape and location is an idealized approximation to how task estimation would occur clinically. Thus we determined how perturbing this idealized prior knowledge impacted the performance of both techniques. To implement the SLE for the non-uniform background, we used a novel iterative algorithm for pre-whitening stationary noise within a compact region. Estimation task performance was compared using the ensemble mean-squared error (EMSE) as the criterion. The SLE method performed substantially better than the ROI method (i.e. EMSE(SLE) was 23-174 times lower) when the background is uniform and tumor location and size are known accurately. The variance of the SLE increased when a non-uniform liver texture was introduced but the EMSE(SLE) continued to be 5-20 times lower than the ROI method. In summary, SLE outperformed ROI under almost all conditions that we tested.

  4. Pink-Beam, Highly-Accurate Compact Water Cooled Slits

    SciTech Connect

    Lyndaker, Aaron; Deyhim, Alex; Jayne, Richard; Waterman, Dave; Caletka, Dave; Steadman, Paul; Dhesi, Sarnjeet

    2007-01-19

    Advanced Design Consulting, Inc. (ADC) has designed accurate compact slits for applications where high precision is required. The system consists of vertical and horizontal slit mechanisms, a vacuum vessel which houses them, water cooling lines with vacuum guards connected to the individual blades, stepper motors with linear encoders, limit (home position) switches and electrical connections including internal wiring for a drain current measurement system. The total slit size is adjustable from 0 to 15 mm both vertically and horizontally. Each of the four blades are individually controlled and motorized. In this paper, a summary of the design and Finite Element Analysis of the system are presented.

  5. Attosecond double-slit experiment.

    PubMed

    Lindner, F; Schätzel, M G; Walther, H; Baltuska, A; Goulielmakis, E; Krausz, F; Milosević, D B; Bauer, D; Becker, W; Paulus, G G

    2005-07-22

    A new scheme for a double-slit experiment in the time domain is presented. Phase-stabilized few-cycle laser pulses open one to two windows (slits) of attosecond duration for photoionization. Fringes in the angle-resolved energy spectrum of varying visibility depending on the degree of which-way information are measured. A situation in which one and the same electron encounters a single and a double slit at the same time is observed. The investigation of the fringes makes possible interferometry on the attosecond time scale. From the number of visible fringes, for example, one derives that the slits are extended over about 500 as.

  6. Attosecond Double-Slit Experiment

    SciTech Connect

    Lindner, F.; Schaetzel, M.G.; Baltuska, A.; Goulielmakis, E.; Walther, H.; Krausz, F.; Milosevic, D.B.; Bauer, D.; Becker, W.; Paulus, G.G.

    2005-07-22

    A new scheme for a double-slit experiment in the time domain is presented. Phase-stabilized few-cycle laser pulses open one to two windows (slits) of attosecond duration for photoionization. Fringes in the angle-resolved energy spectrum of varying visibility depending on the degree of which-way information are measured. A situation in which one and the same electron encounters a single and a double slit at the same time is observed. The investigation of the fringes makes possible interferometry on the attosecond time scale. From the number of visible fringes, for example, one derives that the slits are extended over about 500 as.

  7. Biphoton double-slit experiment

    SciTech Connect

    Brida, G.; Cagliero, E.; Falzetta, G.; Genovese, M.; Gramegna, M.; Predazzi, E.

    2003-09-01

    In this paper we present a double-slit experiment where two indistinguishable photons produced by type-I parametric down-conversion are each sent to a well-defined slit. Data about the diffraction and interference patterns for coincidences are presented and discussed. An analysis of these data allows a test of standard quantum mechanics against the de Broglie-Bohm theory.

  8. Reflection z-scan measurements of the non-linear lens in VECSEL gain structures

    NASA Astrophysics Data System (ADS)

    Shaw, Ed A.; Quarterman, Adrian H.; Turnbull, Andrew P.; Chen Sverre, Theo; Head, C. R.; Tropper, Anne C.; Wilcox, Keith G.

    2016-03-01

    We present reflection z-scan measurements of a quantum well VECSEL gain structure under pumped and unpumped conditions. The implications for the design of mode-locked cavities will be discussed; both in relation to SESAM mode-locked lasers and the possibility of self-mode-locking.

  9. Linear terrestrial laser scanning using array avalanche photodiodes as detectors for rapid three-dimensional imaging.

    PubMed

    Cai, Yinqiao; Tong, Xiaohua; Tong, Peng; Bu, Hongyi; Shu, Rong

    2010-12-01

    As an active remote sensor technology, the terrestrial laser scanner is widely used for direct generation of a three-dimensional (3D) image of an object in the fields of geodesy, surveying, and photogrammetry. In this article, a new laser scanner using array avalanche photodiodes, as designed by the Shanghai Institute of Technical Physics of the Chinese Academy of Sciences, is introduced for rapid collection of 3D data. The system structure of the new laser scanner is first presented, and a mathematical model is further derived to transform the original data to the 3D coordinates of the object in a user-defined coordinate system. The performance of the new laser scanner is tested through a comprehensive experiment. The result shows that the new laser scanner can scan a scene with a field view of 30° × 30° in 0.2 s and that, with respect to the point clouds obtained on the wall and ground floor surfaces, the root mean square errors for fitting the two planes are 0.21 and 0.01 cm, respectively. The primary advantages of the developed laser scanner include: (i) with a line scanning mode, the new scanner achieves simultaneously the 3D coordinates of 24 points per single laser pulse, which enables it to scan faster than traditional scanners with a point scanning mode and (ii) the new scanner makes use of two galvanometric mirrors to deflect the laser beam in both the horizontal and the vertical directions. This capability makes the instrument smaller and lighter, which is more acceptable for users.

  10. Image reconstruction based on total-variation minimization and alternating direction method in linear scan computed tomography

    NASA Astrophysics Data System (ADS)

    Zhang, Han-Ming; Wang, Lin-Yuan; Yan, Bin; Li, Lei; Xi, Xiao-Qi; Lu, Li-Zhong

    2013-07-01

    Linear scan computed tomography (LCT) is of great benefit to online industrial scanning and security inspection due to its characteristics of straight-line source trajectory and high scanning speed. However, in practical applications of LCT, there are challenges to image reconstruction due to limited-angle and insufficient data. In this paper, a new reconstruction algorithm based on total-variation (TV) minimization is developed to reconstruct images from limited-angle and insufficient data in LCT. The main idea of our approach is to reformulate a TV problem as a linear equality constrained problem where the objective function is separable, and then minimize its augmented Lagrangian function by using alternating direction method (ADM) to solve subproblems. The proposed method is robust and efficient in the task of reconstruction by showing the convergence of ADM. The numerical simulations and real data reconstructions show that the proposed reconstruction method brings reasonable performance and outperforms some previous ones when applied to an LCT imaging problem.

  11. High-performance hyperspectral imaging using virtual slit optics

    NASA Astrophysics Data System (ADS)

    Behr, Bradford B.; Bismilla, Yusuf; Cenko, Andrew T.; DesRoches, Brandon; Meade, Jeffrey T.; Munro, Elizabeth A.; Slaa, Jared; Hajian, Arsen R.

    2014-05-01

    Tornado Spectral Systems (TSS) has developed High Throughput Virtual Slit (HTVS) technology that improves the performance of spectrometers by factors of several while maintaining system size. In the simplest configuration, the HTVS allows optical designers to remove the lossy slit from a spectrometer, greatly increasing throughput without a loss of resolution. This is especially useful in many standoff applications, where every photon matters. TSS has tested multiple configurations of HTVS spectral sensing and spectral imaging technology, including standoff sensing, point scan imaging, long-slit pushbroom imaging and similar configurations. The HTVS throughput-resolution advantage allows us to increase scanning speed, decrease system size, decrease aperture, decrease source intensity requirements or some combination of all four. HTVS technology expands the realm of viable spectral imaging applications. We discuss the applicability of this technology to spectral imaging and standoff sensing and present experimental results from several prototype and production spectrometers.

  12. Optical double-slit particle measuring system

    DOEpatents

    Tichenor, D.A.; Wang, J.C.F.; Hencken, K.R.

    1982-03-25

    A method for in situ measurement of particle size is described. The size information is obtained by scanning an image of the particle across a double-slit mask and observing the transmitted light. This method is useful when the particle size of primary interest is 3..mu..m and larger. The technique is well suited to applications in which the particles are non-spherical and have unknown refractive index. It is particularly well suited to high temperature environments in which the particle incandescence provides the light source.

  13. Optical double-slit particle measuring system

    DOEpatents

    Hencken, Kenneth R.; Tichenor, Daniel A.; Wang, James C. F.

    1984-01-01

    A method for in situ measurement of particle size is described. The size information is obtained by scanning an image of the particle across a double-slit mask and observing the transmitted light. This method is useful when the particle size of primary interest is 3 .mu.m and larger. The technique is well suited to applications in which the particles are non-spherical and have unknown refractive index. It is particularly well suited to high temperature environments in which the particle incandescence provides the light source.

  14. SEM analysis of ionizing radiation effects in linear integrated circuits. [Scanning Electron Microscope

    NASA Technical Reports Server (NTRS)

    Stanley, A. G.; Gauthier, M. K.

    1977-01-01

    A successful diagnostic technique was developed using a scanning electron microscope (SEM) as a precision tool to determine ionization effects in integrated circuits. Previous SEM methods radiated the entire semiconductor chip or major areas. The large area exposure methods do not reveal the exact components which are sensitive to radiation. To locate these sensitive components a new method was developed, which consisted in successively irradiating selected components on the device chip with equal doses of electrons /10 to the 6th rad (Si)/, while the whole device was subjected to representative bias conditions. A suitable device parameter was measured in situ after each successive irradiation with the beam off.

  15. Bandwidth control of forbidden transmission gaps in compound structures with subwavelength slits.

    PubMed

    Skigin, Diana C; Loui, Hung; Popovic, Zoya; Kuester, Edward F

    2007-07-01

    Phase resonances in transmission compound structures with subwavelength slits produce sharp dips in the transmission response. For all equal slits, the wavelengths of these sharp transmission minima can be varied by changing the width or the length of all the slits. In this paper we show that the width of the dip, i.e., the frequency range of minimum transmittance, can be controlled by making at least one slit different from the rest within a compound unit cell. In particular, we investigate the effect that a change in the dielectric filling, or in the length of a single slit, produces in the transmission response. We also analyze the scan angle behavior of these structures by means of band diagrams and compare them with previous results for all-equal slit structures.

  16. [The linear hyperspectral camera rotating scan imaging geometric correction based on the precise spectral sampling].

    PubMed

    Wang, Shu-min; Zhang, Ai-wu; Hu, Shao-xing; Wang, Jing-meng; Meng, Xian-gang; Duan, Yi-hao; Sun, Wei-dong

    2015-02-01

    As the rotation speed of ground based hyperspectral imaging system is too fast in the image collection process, which exceeds the speed limitation, there is data missed in the rectified image, it shows as the_black lines. At the same time, there is serious distortion in the collected raw images, which effects the feature information classification and identification. To solve these problems, in this paper, we introduce the each component of the ground based hyperspectral imaging system at first, and give the general process of data collection. The rotation speed is controlled in data collection process, according to the image cover area of each frame and the image collection speed of the ground based hyperspectral imaging system, And then the spatial orientation model is deduced in detail combining with the star scanning angle, stop scanning angle and the minimum distance between the sensor and the scanned object etc. The oriented image is divided into grids and resampled with new spectral. The general flow of distortion image corrected is presented in this paper. Since the image spatial resolution is different between the adjacent frames, and in order to keep the highest image resolution of corrected image, the minimum ground sampling distance is employed as the grid unit to divide the geo-referenced image. Taking the spectral distortion into account caused by direct sampling method when the new uniform grids and the old uneven grids are superimposed to take the pixel value, the precise spectral sampling method based on the position distribution is proposed. The distortion image collected in Lao Si Cheng ruin which is in the Zhang Jiajie town Hunan province is corrected through the algorithm proposed on above. The features keep the original geometric characteristics. It verifies the validity of the algorithm. And we extract the spectral of different features to compute the correlation coefficient. The results show that the improved spectral sampling method is

  17. Specific expression and methylation of SLIT1, SLIT2, SLIT3, and miR-218 in gastric cancer subtypes.

    PubMed

    Kim, Mirang; Kim, Jong-Hwan; Baek, Su-Jin; Kim, Seon-Young; Kim, Yong Sung

    2016-06-01

    SLIT has been suggested as a key regulator of cancer development and a promising therapeutic target for cancer treatment. Herein, we analyzed expression and methylation of SLIT1/SLIT2/SLIT3 in 11 gastric cancer cell lines, 96 paired gastric tumors and adjacent normal gastric tissues, and 250 gastric cancers provided by The Cancer Genome Atlas. Methylation of SLIT1/SLIT2/SLIT3 was found both in early gastric cancers, and in advanced gastric cancers. Even normal gastric tissue showed increased methylation of SLIT1 and SLIT3 that correlated with patient age. Furthermore, epigenetic inactivation of SLIT occurred in a gastric cancer subtype-dependent manner. SLIT2 and SLIT3 expression was reduced in Epstein-Barr virus-positive and microsatellite instability subtypes, but increased in the genomically stable subtype. Expression of miR‑218 correlated negatively with methylation of SLIT2 or SLIT3. These findings suggest that a molecular subtype-specific therapeutic strategy is needed for targeting SLITs and miR-218 in treatment of gastric cancer.

  18. Frequent epigenetic inactivation of the SLIT2 gene in chronic and acute lymphocytic leukemia.

    PubMed

    Dunwell, Thomas L; Dickinson, Rachel E; Stankovic, Tatjana; Dallol, Ashraf; Weston, Victoria; Austen, Belinda; Catchpoole, Daniel; Maher, Eamonn R; Latif, Farida

    2009-05-16

    Recently a mouse model of T/natural killer acute lymphoblastic leukemia was used to assess global promoter methylation across the mouse genome using the restriction landmark genomic scanning technique. One of the methylated mouse genes identified in this way was Slit2. There are three mammalian SLIT genes (SLIT1, SLIT2, SLIT3), that belong to a highly conserved family of axon guidance molecules. We have previously demonstrated that SLIT2 is frequently inactivated in lung, breast, colorectal and glioma tumors by hypermethylation of a CpG island in its promoter region, whilst inactivating somatic mutations are rare. Furthermore, we demonstrated that SLIT2 acts as a tumor suppressor gene in breast and colorectal cancer cells. In this report we determined the methylation status of the SLIT2 gene in leukemias (CLL and ALL). SLIT2 was methylated in all ten leukemia cell lines analyzed (eight completely and two partially methylated). SLIT2 expression was restored after treating ALL lines with 5-aza-2dC. In primary ALL and CLL samples, SLIT2 was also frequently methylated, 58% (30/52) B-ALL; 83% (10/12) T-ALL and in 80% (24/30) CLL. Whilst DNA from peripheral blood and bone marrow from healthy control samples showed no SLIT2 methylation. Methylation results in leukemia cell lines and ALL and CLL primary samples were confirmed by direct sequencing of bisulfite modified DNA. Our results demonstrate that methylation of the SLIT2 5' CpG island is conserved between mice and humans, and therefore is likely to be of functional importance.

  19. Linear HgCdTe IR FPA 288×4 with bidirectional scanning

    NASA Astrophysics Data System (ADS)

    Vasilyev, V. V.; Predein, A. V.; Varavin, V. S.; Mikhailov, N. N.; Dvoretsky, S. A.; Gumenjuk-Sichevska, J. V.; Golenkov, A. G.; Reva, V. P.; Sabinina, I. V.; Sidorov, Yu. G.; Susliakov, A. O.; Sizov, F. F.; Aseev, A. L.

    2010-09-01

    The long wavelength (8-12 μm) IR FPA 288×4 based on a hybrid assembly of n+-p diode photosensitive arrays (PA) of HgCdTe (MCT) MBE-grown structures and time delay integration (TDI) readout integrated circuits (ROIC) with bidirectional scanning have been developed, fabricated, and investigated. The p-type MCT structures were obtained by thermal annealing of as-grown n-type material in inert atmosphere. The MCT photosensitive layer with the composition 0.20-0.23 of mole fraction of CdTe was surrounded by the wide gap layers to decrease the recombination rate and surface leakage current. The diode arrays were fabricated by planar implantation of boron ions into p-MCT. The typical dark currents were about 4-7 nA at the reverse bias voltage of 150 mV. The differential resistance R was up to R0 = 1.6×107 Ω zero bias voltage, which corresponded to R0A ˜70 Ω ·cm2 and to the maximal value Rmax = 2.1 × 108 Ω. The bidirectional TDI deselecting ROIC was developed and fabricated by 1.0-μm CMOS technology with two metallic and two polysilicon layers. The IR FPAs were free of defect channels and have the average values of responsivity Sλ = 2.27×108 V/W, the detectivity Dλ * = 2.13 × 1011 cm × Hz1/2 × Wt1, and the noise equivalent temperature difference NETD = 9 mK.

  20. A simulation of electromigration-induced transgranular slits

    NASA Astrophysics Data System (ADS)

    Wang, Weiqing; Suo, Z.; Hao, T.-H.

    1996-03-01

    An on-chip aluminum interconnect carries an intense electric current at an elevated temperature, motivating atoms to diffuse in the solid state, and inducing voids that may cause an open failure. Recent observations have shown that a void sometimes collapses to a slit running nearly perpendicular to the electric current direction. Such a slit often lies inside a grain rather than along a grain boundary. An earlier calculation showed that diffusion on the void surface, driven by the electric current, can cause a circular void to translate in an infinite, isotropic interconnect. It was suggested recently that this solution may be unstable, and that two forces compete in determining the void stability: surface tension favors a rounded void, and the electric current favors a slit. A linear perturbation analysis, surprisingly, revealed that the translating circular void is stable against infinitesimal shape perturbation. Consequently, the slit instability must have resulted from finite imperfections. This article reviews the experimental and theoretical findings, and describes a numerical simulation of finite void shape change. We determine the electric field by a conformal mapping of complex variables, and update the void shape for a time step by a variational method. The simulation shows that a finite void shape imperfection or surface tension anisotropy can cause a void to collapse to a slit.

  1. "Quantum Interference with Slits" Revisited

    ERIC Educational Resources Information Center

    Rothman, Tony; Boughn, Stephen

    2011-01-01

    Marcella has presented a straightforward technique employing the Dirac formalism to calculate single- and double-slit interference patterns. He claims that no reference is made to classical optics or scattering theory and that his method therefore provides a purely quantum mechanical description of these experiments. He also presents his…

  2. Slit Function Measurement of An Imaging Spectrograph Using Fourier Transform Techniques

    NASA Technical Reports Server (NTRS)

    Park, Hongwoo; Swimyard, Bruce; Jakobsen, Peter; Moseley, Harvey; Greenhouse, Matthew

    2004-01-01

    Knowledge of a spectrograph slit function is necessary to interpret the unresolved lines in an observed spectrum. A theoretical slit function can be calculated from the sizes of the entrance slit, the detector aperture when it functions as an exit slit, the dispersion characteristic of the disperser, and the point spread function of the spectrograph. A measured slit function is preferred to the theoretical one for the correct interpretation of the spectral data. In a scanning spectrometer with a single exit slit, the slit function is easily measured. In a fixed grating/or disperser spectrograph, illuminating the entrance slit with a near monochromatic light from a pre-monochrmator or a tunable laser and varying the wavelength of the incident light can measure the slit function. Even though the latter technique had been used successfully for the slit function measurements, it had been very laborious and it would be prohibitive to an imaging spectrograph or a multi-object spectrograph that has a large field of view. We explore an alternative technique that is manageable for the measurements. In the proposed technique, the imaging spectrograph is used as a detector of a Fourier transform spectrometer. This method can be applied not only to an IR spectrograph but also has a potential to a visible/UV spectrograph including a wedge filter spectrograph. This technique will require a blackbody source of known temperature and a bolometer to characterize the interferometer part of the Fourier Transform spectrometer. This pa?er will describe the alternative slit function measurement technique using a Fourier transform spectrometer.

  3. High-performance hyperspectral imaging using virtual slit optics

    NASA Astrophysics Data System (ADS)

    Behr, Bradford B.; Meade, Jeffrey T.; Hajian, Arsen R.; Cenko, Andrew T.

    2013-05-01

    The High Throughput Virtual Slit (or HTVS) is a new optical technology which can significantly increase the throughput and resolution of a dispersive spectrometer. The HTVS is able to preserve spectrometer étendue, mitigating photon losses normally associated with a slit. Originally implemented in multimode fiber-input spectrometers, HTVS has now been shown to be broadly applicable to a wide variety of spatially scanning hyperspectral imagers and standoff sensors, enhancing their performance and unlocking new application areas. In essence, the anamorphic elements of the HTVS optical system provide a means to decouple the spatial (iFOV) and spectral resolution of nearly any HSI system. In some scenarios, HTVS can be used to achieve better spectral resolution with the same input slit width. Alternatively, the slit can be widened (to increase the collected signal) while maintaining the same spectral resolution. This newfound flexibility in optimizing critical performance parameters not only improves the performance of HSI systems in existing remote sensing contexts, but also opens up numerous new application areas which were previously inaccessible to hyperspectral techniques. This method adds substantial value to existing HSI designs, particularly in applications involving targets with large spatial extent and requiring high spectral resolution (e.g. standoff Raman spectroscopy). We present recent experimental results from our prototype HTVS pushbroom imager and discuss case studies of standoff Raman detection of hazardous materials, passive detection of faint narrowband and monochromatic sources, and optimal disentangling of target spectral signatures from the solar spectrum under daytime illumination.

  4. Improved 6-Plex Tandem Mass Tags Quantification Throughput Using a Linear Ion Trap-High-Energy Collision Induced Dissociation MS(3) Scan.

    PubMed

    Liu, Jane M; Sweredoski, Michael J; Hess, Sonja

    2016-08-01

    The use of tandem mass tags (TMT) as an isobaric labeling strategy is a powerful method for quantitative proteomics, yet its accuracy has traditionally suffered from interference. This interference can be largely overcome by selecting MS(2) fragment precursor ions for high-energy collision induced dissociation (HCD) MS(3) analysis in an Orbitrap scan. While this approach minimizes the interference effect, sensitivity suffers due to the high AGC targets and long acquisition times associated with MS(3) Orbitrap detection. We investigated whether acquiring the MS(3) scan in a linear ion trap with its lower AGC target would increase overall quantification levels with a minimal effect on precision and accuracy. Trypsin-digested proteins from Saccharomyces cerevisiae were tagged with 6-plex TMT reagents. The sample was subjected to replicate analyses using either the Orbitrap or the linear ion trap for the HCD MS(3) scan. HCD MS(3) detection in the linear ion trap vs Orbitrap increased protein identification by 66% with minor loss in precision and accuracy. Thus, the use of a linear ion trap-HCD MS(3) scan during a 6-plex TMT experiment can improve overall identification levels while maintaining the power of multiplexed quantitative analysis. PMID:27377715

  5. Feasibility of Concurrent Treatment with the Scanning Ultrasound Reflector Linear Array System (SURLAS) and the Helical Tomotherapy System

    PubMed Central

    Peñagarícano, José A.; Moros, Eduardo; Novák, Petr; Yan, Yulong; Corry, Peter

    2010-01-01

    Purpose To evaluate the feasibility of concurrent treatment with the Scanning Ultrasound Reflector Linear Array System (SURLAS) and helical tomotherapy (HT) intensity modulated radiation therapy (IMRT). Methods The SURLAS was placed on a RANDO phantom simulating a patient with superficial or deep recurrent breast cancer. A Megavoltage CT (MVCT) of the phantom with and without the SURLAS was obtained in the HT system. MVCT images with the SURLAS were obtained for two configurations: i) with the SURLAS' long axis parallel and ii) perpendicular to the longitudinal axis of the phantom. The MVCT simulation data set was then transferred to a radiation therapy planning station. Organs at risk (OAR) were contoured including the lungs, heart, abdomen and spinal cord. The metallic parts of the SURLAS were contoured as well and constraints were assigned to completely or directionally block radiation through them. The MVCT-simulation data set and regions of interest (ROI) files were subsequently transferred to the HT planning station. Several HT plans were obtained with optimization parameters that are usually used in the clinic. For comparison purposes, planning was also performed without the SURLAS on the phantom. Results All plans with the SURLAS on the phantom showed adequate dose covering 95% of the planning target volume (PTV D95%), average dose and coefficient of variation of the planning target volume (PTV) dose distribution regardless of the SURLAS' orientation with respect to the RANDO phantom. Likewise, all OAR showed clinically acceptable dose values. Spatial dose distributions and dose-volume histogram (DVH) evaluation showed negligible plan degradation due to the presence of the SURLAS. Beam-on time varied depending on the selected optimization parameters. Conclusion From the perspective of the radiation dosage, concurrent treatment with the SURLAS and HT IMRT is feasible as demonstrated by the obtained clinically acceptable treatment plans. In addition, proper

  6. Slit lamp photography: The basics.

    PubMed

    Painter, Rosalyn

    2015-06-01

    This introductory paper is designed to explain the basics of slit lamp photography with the use of illustrations and sample images. The two primary methods of illumination are described with reference to positioning and magnification, as well as the use of background illumination. Filters and dye usage are described along with a brief explanation of associated imaging techniques. Further explanation of techniques will be looked at in subsequent articles, this paper aims to give an over view rather than an in-depth discussion of techniques.

  7. Design of decoupled dual servo stage with voice coil motor and linear motor for XY long stroke ultra-precision scanning system

    NASA Astrophysics Data System (ADS)

    Kim, Ki-Hyun; Choi, Young-Man; Gweon, Dae-Gab; Hong, Dong-Pyo; Kim, Koung-Suk; Lee, Suk-Won; Lee, Moon-Gu

    2005-12-01

    A decoupled dual servo (DDS) stage for ultra-precision scanning system is introduced in this paper. The proposed DDS consists of a 3 axis fine stage for handling and carrying workpieces and a XY coarse stage. Especially, the DDS uses three voice coil motors (VCM) as a planar actuation system of the fine stage to reduce the disturbances due to any mechanical connections with its coarse stage. VCMs are governed by Lorentz law. According to the law and its structure, there are no mechanical connections between coils and magnetic circuits. Moreover, the VCM doesn't have force ripples due to imperfections of commutation components of linear motor systems - currents and flux densities. However, due to the VCM's mechanical constraints the working range of the fine is about 5mm2. To break that hurdle, the coarse stage with linear motors is used for the fine stage to move about 200mm2. Because of the above reasons, the proposed DDS can achieve higher precision scanning than other stages with only one servo. Using MATLAB's Sequential Quadratic Programming (SQP), the VCMs are optimally designed for the highest force under conditions and constraints such as thermal dissipations due to its coil, its size, and so on. For linear motors, Halbach magnet linear motor is proposed and optimally designed in this paper. In addition, for their smooth movements without any frictions, guide systems of the DDS are composed of air bearings. And then, precisely to get their positions, linear scales with 0.1um resolution are used for the coarse's XY motions and plane mirror laser interferometers with 20nm for the fine's XYθz. On scanning, the two stages have same trajectories and are controlled. The control algorithm is Parallel method. The embodied ultra-precision scanning system has about 100nm tracking error and in-positioning stability.

  8. Development of high-temperature pulsed slit nozzle and its application to supersonic jet absorption spectrometry.

    PubMed

    Kawamura, S; Lin, C H; Imasaka, T

    1994-11-01

    A high-temperature pulsed slit nozzle, consisting of a circular pulsed nozzle and an interface to convert a circular flow into a slit flow has been constructed. The absorption spectrum is measured by scanning the wavelength of the monochromator equipped with a xenon arc lamp and by detecting the transmitted light through a jet with a photomultiplier. A rotationally cooled spectrum is clearly observed for aniline only when a long slit nozzle is employed. The absorptivity increases proportionally to the slit length at least up to 6 cm. The time for recording a spectrum is 3.5 min, which is reduced to several seconds by transmitting a white light through a jet and by measuring the spectrum with an optical multichannel analyzer. The detection limit is estimated to a partial vapor pressure of 0.4 torr for aniline. The present system can be conveniently used in routine analysis, because of a wide spectral coverage of the lamp source.

  9. Time-resolved double-slit interference pattern measurement with entangled photons

    PubMed Central

    Kolenderski, Piotr; Scarcella, Carmelo; Johnsen, Kelsey D.; Hamel, Deny R.; Holloway, Catherine; Shalm, Lynden K.; Tisa, Simone; Tosi, Alberto; Resch, Kevin J.; Jennewein, Thomas

    2014-01-01

    The double-slit experiment strikingly demonstrates the wave-particle duality of quantum objects. In this famous experiment, particles pass one-by-one through a pair of slits and are detected on a distant screen. A distinct wave-like pattern emerges after many discrete particle impacts as if each particle is passing through both slits and interfering with itself. Here we present a temporally- and spatially-resolved measurement of the double-slit interference pattern using single photons. We send single photons through a birefringent double-slit apparatus and use a linear array of single-photon detectors to observe the developing interference pattern. The analysis of the buildup allows us to compare quantum mechanics and the corpuscular model, which aims to explain the mystery of single-particle interference. Finally, we send one photon from an entangled pair through our double-slit setup and show the dependence of the resulting interference pattern on the twin photon's measured state. Our results provide new insight into the dynamics of the buildup process in the double-slit experiment, and can be used as a valuable resource in quantum information applications. PMID:24770360

  10. Time-resolved double-slit interference pattern measurement with entangled photons

    NASA Astrophysics Data System (ADS)

    Kolenderski, Piotr; Scarcella, Carmelo; Johnsen, Kelsey D.; Hamel, Deny R.; Holloway, Catherine; Shalm, Lynden K.; Tisa, Simone; Tosi, Alberto; Resch, Kevin J.; Jennewein, Thomas

    2014-04-01

    The double-slit experiment strikingly demonstrates the wave-particle duality of quantum objects. In this famous experiment, particles pass one-by-one through a pair of slits and are detected on a distant screen. A distinct wave-like pattern emerges after many discrete particle impacts as if each particle is passing through both slits and interfering with itself. Here we present a temporally- and spatially-resolved measurement of the double-slit interference pattern using single photons. We send single photons through a birefringent double-slit apparatus and use a linear array of single-photon detectors to observe the developing interference pattern. The analysis of the buildup allows us to compare quantum mechanics and the corpuscular model, which aims to explain the mystery of single-particle interference. Finally, we send one photon from an entangled pair through our double-slit setup and show the dependence of the resulting interference pattern on the twin photon's measured state. Our results provide new insight into the dynamics of the buildup process in the double-slit experiment, and can be used as a valuable resource in quantum information applications.

  11. Time-resolved double-slit interference pattern measurement with entangled photons.

    PubMed

    Kolenderski, Piotr; Scarcella, Carmelo; Johnsen, Kelsey D; Hamel, Deny R; Holloway, Catherine; Shalm, Lynden K; Tisa, Simone; Tosi, Alberto; Resch, Kevin J; Jennewein, Thomas

    2014-04-28

    The double-slit experiment strikingly demonstrates the wave-particle duality of quantum objects. In this famous experiment, particles pass one-by-one through a pair of slits and are detected on a distant screen. A distinct wave-like pattern emerges after many discrete particle impacts as if each particle is passing through both slits and interfering with itself. Here we present a temporally- and spatially-resolved measurement of the double-slit interference pattern using single photons. We send single photons through a birefringent double-slit apparatus and use a linear array of single-photon detectors to observe the developing interference pattern. The analysis of the buildup allows us to compare quantum mechanics and the corpuscular model, which aims to explain the mystery of single-particle interference. Finally, we send one photon from an entangled pair through our double-slit setup and show the dependence of the resulting interference pattern on the twin photon's measured state. Our results provide new insight into the dynamics of the buildup process in the double-slit experiment, and can be used as a valuable resource in quantum information applications.

  12. Triterpenoid saponins profiling by adducts-targeted neutral loss triggered enhanced resolution and product ion scanning using triple quadrupole linear ion trap mass spectrometry.

    PubMed

    Yan, Zhixiang; Lin, Ge; Ye, Yang; Wang, Yitao; Yan, Ru

    2014-03-28

    Triterpenoid saponins (TSs) are a unique class of high molecular weight glycosides and have been frequently used in cosmetic and phytotherapy industry. There is a great need to comprehensively profile these plant metabolites for studying their functions. In the present study, a novel adducts targeted neutral loss (NL), triggered enhanced resolution (ER) and enhanced product ion (EPI) scanning approach were described for TSs profiling using a triple quadrupole linear ion trap mass spectrometry. This approach circumvented the disadvantages of poor glycosidic bond cleavage of TSs by monitoring the NH3 (NL17) and HCOOH (NL46) loss of their abundant ammonium and formate adducts, respectively. The sugar-loss independent NL scanning served as a sensitive survey scan and triggered information-dependent ER and EPI scans to increase peak assignment confidence. NL17 was superior to NL46 for TSs characterization due to the better fragmentation of ammonium adducts than formate adducts. For those TSs undetectable by NL17, precursor ion (PI) scan for sapogenin fragments could be used to screen out non-adducted TSs. The NL/PI-ER-EPI approach was applied for TSs profiling in Astragali Radix, a famous medicinal and nutritional plant widely used in Asian countries and United States. In total, 136 TSs were detected while previous research using high resolution mass spectrometry based full scan only detected 22 TSs in this herb.

  13. A subset of chicken statoacoustic ganglion neurites are repelled by Slit1 and Slit2

    PubMed Central

    Battisti, Andrea C.; Fantetti, Kristen N.; Moyers, Bryan A.; Fekete, Donna M.

    2014-01-01

    Mechanosensory hair cells in the chicken inner ear are innervated by bipolar afferent neurons of the statoacoustic ganglion (SAG). During development, individual SAG neurons project their peripheral process to only one of eight distinct sensory organs. These neuronal subtypes may respond differently to guidance cues as they explore the periphery in search of their target. Previous gene expression data suggested that Slit repellants might channel SAG neurites into the sensory primordia, based on the presence of robo transcripts in the neurons and the confinement of slit transcripts to the flanks of the prosensory domains. This led to the prediction that excess Slit proteins would impede the outgrowth of SAG neurites. As predicted, axonal projections to the primordium of the anterior crista were reduced 2-3 days after electroporation of either slit1 or slit2 expression plasmids into the anterior pole of the otocyst on embryonic day 3 (E3). The posterior crista afferents, which normally grow through and adjacent to slit expression domains as they are navigating towards the posterior pole of the otocyst, did not show Slit responsiveness when similarly challenged by ectopic delivery of slit to their targets. The sensitivity to ectopic Slits shown by the anterior crista afferents was more the exception than the rule: responsiveness to Slits was not observed when the entire E4 SAG was challenged with Slits for 40 hours in vitro. The corona of neurites emanating from SAG explants was unaffected by the presence of purified human Slit1 and Slit2 in the culture medium. Reduced axon outgrowth from E8 olfactory bulbs cultured under similar conditions for 24 hours confirmed bioactivity of purified human Slits on chicken neurons. In summary, differential sensitivity to Slit repellents may influence the directional outgrowth of otic axons toward either the anterior or posterior otocyst. PMID:24456709

  14. Acoustic transmission through compound subwavelength slit arrays

    NASA Astrophysics Data System (ADS)

    Ward, G. P.; Hibbins, A. P.; Sambles, J. R.; Smith, J. D.

    2016-07-01

    The angular dependence of the transmission of sound in air through four types of two-dimensional slit arrays formed of aluminium slats is explored, both experimentally and numerically. For a simple, subwavelength periodic slit array, it is well known that Fabry-Perot-like waveguide resonances, supported by the slit cavities, coupled to diffracted evanescent waves, result in enhanced acoustic transmission at frequencies determined by the length, width, and separation of each slit cavity. We demonstrate that altering the spacing or width of some of the slits to form a compound array (i.e., an array having a basis comprised of more than one slit) results in sharp dips in the transmission spectra, which may have a strong angular dependence. These features correspond to phase resonances, which have been studied extensively in the electromagnetic case. This geometry allows for additional near-field configurations compared to the simple array, whereby the field in adjacent cavities can be out of phase. Several types of compound slit arrays are investigated; one such structure is optimized to minimize the effect of boundary-layer loss mechanisms present in each slit cavity, thereby achieving a deep, sharp transmission minimum in a broad maximum.

  15. SLIT: indications, follow-up, and management.

    PubMed

    Dávila, I; Navarro, A; Domínguez-Ortega, J; Alonso, A; Antolín-Amérigo, D; Diéguez, M C; González-Mancebo, E; Martíns, C; Martínez, C; Núñez, B; Prior, N; Rechel, M; Rosado, A; Ruiz-Hornillos, J; Sansosti, A; Torrecillas, M; Jerez, M J

    2014-01-01

    Specific sublingual immunotherapy (SLIT) has been proved to be a safe and effective approach in respiratory allergy. However, further research is required on aspects such as patient selection, use of optimal dosing, effects on asthma, long-term effects, and management of adverse reactions. In addition, the widely heterogeneous nature of studies on SLIT performed to date and the application of the criteria for subcutaneous immunotherapy make it difficult for the prescribing clinician to draw accurate and useful conclusions. Therefore, the QUASAR Group (QUality in the Administration of SLIT in Allergic Rhinitis), which comprises allergologists with broad clinical experience in SLIT, investigated the latest research findings and available data on this approach. Working parties were formed in 3 different categories: selection of candidates for SLIT, treatment efficacy, and adverse reactions. We performed a PubMed search for articles that were representative of each category and found 850. From these, we finally selected 266 articles, which were reviewed to retrieve data on SLIT. Evidence for each clinical question was graded according to the Oxford classification. The resulting text was evaluated on 3 occasions by all the members of the group until the final version was agreed upon. In this version, we review available evidence on SLIT, particularly with pollens, which is the subject of most articles. In areas where evidence is insufficient, an alternative agreed upon by the members of the QUASAR group is presented. Finally, we propose algorithms for selecting candidates for SLIT and for management of adverse events.

  16. Spectrally encoded slit confocal microscopy using a wavelength-swept laser

    NASA Astrophysics Data System (ADS)

    Kim, Soocheol; Hwang, Jaehyun; Heo, Jung; Ryu, Suho; Lee, Donghak; Kim, Sang-Hoon; Oh, Seung Jae; Joo, Chulmin

    2015-03-01

    We present an implementation of spectrally encoded slit confocal microscopy. The method employs a rapid wavelength-swept laser as the light source and illuminates a specimen with a line focus that scans through the specimen as the wavelength sweeps. The reflected light from the specimen is imaged with a stationary line scan camera, in which the finite pixel height serves as a slit aperture. This scanner-free operation enables a simple and cost-effective implementation in a small form factor, while allowing for the three-dimensional imaging of biological samples.

  17. Alice through the double slits

    NASA Astrophysics Data System (ADS)

    Davies, G. G.

    2010-02-01

    Alice thought that she had simply followed the White Rabbit through one of the two slit-like holes, but felt strangely disturbed about whether she had "really" gone through just one hole, or had somehow passed through both holes simultaneously. The Rabbit, who was eating a turnip, was looking her over. "You must be one of those funny-looking things that thinks they know everything," he said. "What are you? A lumpy wave or a wavy lump?" "I don't feel like either," said Alice, "so I must be something entirely different." The Rabbit snorted. "Well, at least you know that," he said. "You might even be ready to learn more."

  18. Solid state slit camera (SSC) onboard MAXI

    NASA Astrophysics Data System (ADS)

    Kimura, Masashi; Tsunemi, Hiroshi; Tomida, Hiroshi; Katayama, Haruyoshi

    2010-07-01

    We report the in orbit status of the MAXI/SSC onboard the international space station (ISS). It was commissioned in August 2009. This is the first all sky survey mission employing X-ray CCDs. It is a slit camera with a field of view of 1.5° × 90° and it scans the sky as the ISS rotates around the earth. The CCD's are cooled down to about -60°C by peltier device and a loop heat pipe. The observation efficiency of the SSC is about 30% due to edge glow, but all of the 32 CCDs in the SSC are cooled down as we expected and functioning property. The performance of the CCD is continuously monitored both by the Mn-K X-rays and by the Cu-K X-rays. There are many sources detected not only point sources but extended sources. But further work in data screening and more observation time is needed to obtain the clear structure of the extended emission.

  19. Diagnostic Accuracy of Ultrasound B scan using 10 MHz linear probe in ocular trauma;results from a high burden country

    PubMed Central

    Shazlee, Muhammad Kashif; Ali, Muhammad; SaadAhmed, Muhammad; Hussain, Ammad; Hameed, Kamran; Lutfi, Irfan Amjad; Khan, Muhammad Tahir

    2016-01-01

    Objective: To study the diagnostic accuracy of Ultrasound B scan using 10 MHz linear probe in ocular trauma. Methods: A total of 61 patients with 63 ocular injuries were assessed during July 2013 to January 2014. All patients were referred to the department of Radiology from Emergency Room since adequate clinical assessment of the fundus was impossible because of the presence of opaque ocular media. Based on radiological diagnosis, the patients were provided treatment (surgical or medical). Clinical diagnosis was confirmed during surgical procedures or clinical follow-up. Results: A total of 63 ocular injuries were examined in 61 patients. The overall sensitivity was 91.5%, Specificity was 98.87%, Positive predictive value was 87.62 and Negative predictive value was 99%. Conclusion: Ultrasound B-scan is a sensitive, non invasive and rapid way of assessing intraocular damage caused by blunt or penetrating eye injuries. PMID:27182245

  20. Extraordinary Optical Absorption through Plasmonic Subwavelength Slits

    NASA Astrophysics Data System (ADS)

    White, Justin; Veronis, Georgios; Yu, Zongfu; Barnard, Edward; Chandran, Anu; Fan, Shanhui; Brongersma, Mark

    2009-03-01

    We report on the ability of resonant plasmonic slits to efficiently concentrate electromagnetic energy into a nanoscale volume of absorbing material placed inside or right behind the slit. This gives rise to extraordinary optical absorption (EOA) characterized by an absorption enhancement factor that well-exceeds the enhancements seen for extraordinary optical transmission (EOT) through slits. A semi-analytic Fabry-Perot model for the resonant absorption is developed and shown to quantitatively agree with full-field simulations. We show that absorption enhancements of nearly 1000% can be realized at 633nm for slits in aluminum films filled with silicon. This effect can be utilized in a wide range of applications, including high speed photodetectors, optical lithography and recording, and biosensors.

  1. Three-dimensional X-ray observation of atmospheric biological samples by linear-array scanning-electron generation X-ray microscope system.

    PubMed

    Ogura, Toshihiko

    2011-01-01

    Recently, we developed a soft X-ray microscope called the scanning-electron generation X-ray microscope (SGXM), which consists of a simple X-ray detection system that detects X-rays emitted from the interaction between a scanning electron beam (EB) and the thin film of the sample mount. We present herein a three-dimensional (3D) X-ray detection system that is based on the SGXM technology and designed for studying atmospheric biological samples. This 3D X-ray detection system contains a linear X-ray photodiode (PD) array. The specimens are placed under a CuZn-coated Si₃N₄ thin film, which is attached to an atmospheric sample holder. Multiple tilt X-ray images of the samples are detected simultaneously by the linear array of X-ray PDs, and the 3D structure is calculated by a new 3D reconstruction method that uses a simulated-annealing algorithm. The resulting 3D models clearly reveal the inner structure of the bacterium. In addition, the proposed method can easily be used for diverse samples in a broad range of scientific fields.

  2. Three-Dimensional X-ray Observation of Atmospheric Biological Samples by Linear-Array Scanning-Electron Generation X-ray Microscope System

    PubMed Central

    Ogura, Toshihiko

    2011-01-01

    Recently, we developed a soft X-ray microscope called the scanning-electron generation X-ray microscope (SGXM), which consists of a simple X-ray detection system that detects X-rays emitted from the interaction between a scanning electron beam (EB) and the thin film of the sample mount. We present herein a three-dimensional (3D) X-ray detection system that is based on the SGXM technology and designed for studying atmospheric biological samples. This 3D X-ray detection system contains a linear X-ray photodiode (PD) array. The specimens are placed under a CuZn-coated Si3N4 thin film, which is attached to an atmospheric sample holder. Multiple tilt X-ray images of the samples are detected simultaneously by the linear array of X-ray PDs, and the 3D structure is calculated by a new 3D reconstruction method that uses a simulated-annealing algorithm. The resulting 3D models clearly reveal the inner structure of the bacterium. In addition, the proposed method can easily be used for diverse samples in a broad range of scientific fields. PMID:21731770

  3. Analytical and Experimental Characterization of a Linear-Array Thermopile Scanning Radiometer for Geo-Synchronous Earth Radiation Budget Applications

    NASA Technical Reports Server (NTRS)

    Sorensen, Ira J.

    1998-01-01

    The Thermal Radiation Group, a laboratory in the department of Mechanical Engineering at Virginia Polytechnic Institute and State University, is currently working towards the development of a new technology for cavity-based radiometers. The radiometer consists of a 256-element linear-array thermopile detector mounted on the wall of a mirrored wedgeshaped cavity. The objective of this research is to provide analytical and experimental characterization of the proposed radiometer. A dynamic end-to-end opto-electrothermal model is developed to simulate the performance of the radiometer. Experimental results for prototype thermopile detectors are included. Also presented is the concept of the discrete Green's function to characterize the optical scattering of radiant energy in the cavity, along with a data-processing algorithm to correct for the scattering. Finally, a parametric study of the sensitivity of the discrete Green's function to uncertainties in the surface properties of the cavity is presented.

  4. Dynamics of ethanol and water mixtures observed in a self-adjusting molecularly thin slit pore.

    PubMed

    Severin, N; Sokolov, I M; Rabe, J P

    2014-04-01

    The structure of multicomponent fluids in confined geometries is a key to understanding their properties. However, it remains an experimental challenge to gain molecular-scale resolution information on this structure. Here we show that mono- and multilayers of graphene, conforming to heterogeneous monolayers of molecules in a flexible slit pore between a mica surface and the graphene layers, allow for mapping the phase separation of water and ethanol within such a slit pore. Employing scanning force microscopy, we readily distinguish clusters of ethanol and water molecules due their different sizes, and we show that the phase separated water-ethanol structures become coarser under thicker graphenes. Moreover, we obtain a lower bound for the two-dimensional diffusion coefficient of ethanol in water of D ≥ 2 × 10(-14) m(2) s(-1). Thus, the molecularly thin slit pore provides a powerful tool to control and to investigate mixed fluids in self-adjusting nanopores.

  5. Slit-Drum Camera For Projectile Studies

    NASA Astrophysics Data System (ADS)

    Liangyi, Chen; Shaoxiang, Zhou; Guanhua, Cha; Yuxi, Hu

    1983-03-01

    The' model XF-70 slit-drum camera has been developed to record projectile in flight for observation and acquisition. It has two operation modes: (1) synchro-ballistic photography, (2) streak record. The film is located on the inner surface of rotating drum to make it travel. The folding mirror is arranged to reflect light beam 90 degree on to film. The assembly of folding mirror and slit aperture can be together rotated about the optical axis of objective so that the camera makes a feature of recording projectile having any launching angle either in synchro-ballistic photography or in streak record through prerotating the folding mirror assembly by an appropriate angle. The mechanical-electric shutter preventing film from reexposing is close to the slit aperture. The loading mechanism is designed for use in daylight. LED fiducial mark and timing mark are printed at the edges of the frame for accurate measurements.

  6. Resolution criteria in double-slit microscopic imaging experiments

    NASA Astrophysics Data System (ADS)

    You, Shangting; Kuang, Cuifang; Zhang, Baile

    2016-09-01

    Double-slit imaging is widely used for verifying the resolution of high-resolution and super-resolution microscopies. However, due to the fabrication limits, the slit width is generally non-negligible, which can affect the claimed resolution. In this paper we theoretically calculate the electromagnetic field distribution inside and near the metallic double slit using waveguide mode expansion method, and acquire the far-field image by vectorial Fourier optics. We find that the slit width has minimal influence when the illuminating light is polarized parallel to the slits. In this case, the claimed resolution should be based on the center-to-center distance of the double-slit.

  7. Efficiency Optimization of Slitted-Core Induction Motor

    NASA Astrophysics Data System (ADS)

    Yetgin, Asim Gökhan; Turan, Mustafa

    2014-01-01

    In this study, a 3kW squirrel cage induction motor having slits in stator and rotor teeth were examined. The slit depth and width in the 56 different slitted motor models were optimized with Finite Element Method Magnetics (FEMM) software by using Finite Elements Method (FEM). What value the depth and width of optimum slit should be was determined in order to obtain maximum motor efficiency in the new motor models created with the proposed slitted structure, and how the depth and width of slit could affect the performance of motor was demonstrated.

  8. Training package 1 for slitting data analysis

    SciTech Connect

    Prime, Michael Bruce

    2015-03-23

    This document and accompanying files are intended as a first training package on how to analyze slitting data. The end goal is to have Idaho National Laboratory (INL) personnel trained to analyze future slitting data taken in the INL Hot Cell on clad, Low-Enriched Uranium (LEU) fuel plates. This first data package will cover data analysis for a monolithic material (as compared to a layered material like the clad fuel plates). The additional issues for layered specimens will be covered in a future training package.

  9. An Eye-adapted Beamforming for Axial B-scans Free from Crystalline Lens Aberration: In vitro and ex vivo Results with a 20 MHz Linear Array

    NASA Astrophysics Data System (ADS)

    Matéo, Tony; Mofid, Yassine; Grégoire, Jean-Marc; Ossant, Frédéric

    In ophtalmic ultrasonography, axial B-scans are seriously deteriorated owing to the presence of the crystalline lens. This strongly aberrating medium affects both spatial and contrast resolution and causes important distortions. To deal with this issue, an adapted beamforming (BF) has been developed and experimented with a 20 MHz linear array working with a custom US research scanner. The adapted BF computes focusing delays that compensate for crystalline phase aberration, including refraction effects. This BF was tested in vitro by imaging a wire phantom through an eye phantom consisting of a synthetic gelatin lens, shaped according to the unaccommodated state of an adult human crystalline lens, anatomically set up in an appropriate liquid (turpentine) to approach the in vivo velocity ratio. Both image quality and fidelity from the adapted BF were assessed and compared with conventional delay-and-sum BF over the aberrating medium. Results showed 2-fold improvement of the lateral resolution, greater sensitivity and 90% reduction of the spatial error (from 758 μm to 76 μm) with adapted BF compared to conventional BF. Finally, promising first ex vivo axial B-scans of a human eye are presented.

  10. Polish device for FOCCoS/PFS slit system

    NASA Astrophysics Data System (ADS)

    de Oliveira, Antonio Cesar; de Oliveira, Ligia Souza; de Arruda, Marcio V.; Souza Marrara, Lucas; dos Santos, Leandro Henrique; Ferreira, Décio; dos Santos, Jesulino Bispo; de Paiva Vilaça, Rodrigo; Rosa, Josimar Aparecido; Sodré Junior, Laerte; de Oliveira, Claudia Mendes

    2014-07-01

    The Fiber Optical Cable and Connector System, "FOCCoS", for the Prime Focus Spectrograph, "PFS", is responsible for transporting light from the Subaru Telescope focal plane to a set of four spectrographs. Each spectrograph will be fed by a convex curved slit with 616 optical fibers organized in a linear arrangement. The slit frontal surface is covered with a special dark composite, made with refractory oxide, which is able to sustain its properties with minimum quantities of abrasives during the polishing process; this stability is obtained This stability is obtained by the detachment of the refractory oxide nanoparticles, which then gently reinforce gently the polishing process and increase its the efficiency. The surface roughness measured in several samples after high performance polishing was about 0.01 microns. Furthermore, the time for obtaining a polished surface with this quality is about 10 times less than the time required for polishing a brass, glass or ceramic surface of the same size. In this paper, we describe the procedure developed for high quality polishing of this type of slit. The cylindrical polishing described here, uses cylindrical concave metal bases on which glass paper is based. The polishing process consists to use grid sequences of 30μm, 12μm, 9μm, 5μm, 3μm, 1μm and, finally, a colloidal silica on a chemical cloth. To obtain the maximum throughput, the surface of the fibers should be polished in such a way that they are optically flat and free from scratches. The optical fibers are inspected with a microscope at all stages of the polishing process to ensure high quality. The efficiency of the process may be improved by using a cylindrical concave composite base as a substrate suitable for diamond liquid solutions. Despite this process being completely by hand, the final result shows a very high quality.

  11. Young's double-slit interference experiment with electrons

    NASA Astrophysics Data System (ADS)

    Frabboni, S.; Gazzadi, G. C.; Pozzi, G.

    2007-11-01

    In this short Note we report a method for producing samples containing two nano-sized slits suitable for demonstrating to undergraduate and graduate students the double-slit electron interference experiment in a conventional transmission electron microscope.

  12. Flow Through Surface Mounted Continuous Slits

    NASA Astrophysics Data System (ADS)

    Tariq, A.; Ali, M. A.; Gad-El-Hak, M.

    2014-11-01

    Ribs are used inside certain gas-turbine blades as passive devices to enhance heat transfer. Slits in those ribs are utilized to control the primary shear layer. The role of secondary flow through a continuous slit behind a surface mounted rib is investigated herein in a rectangular duct using hotwire anemometry and particle image velocimetry. Changing the open-area-ratio and the slit's location within the rib dominate the observed shear layer. The behavior of discrete Fourier modes of the velocity fluctuations generated by different configurations is explored. Two distinct flow mechanisms are observed in the rib's wake. Both mechanisms are explained on the basis of large-scale spectral peak in the shear layer. The results show the successful impact of changing the open-area-ratio by manipulating the small-scale vortices at the leeward corner of the rib, which is suspected to be the potential cause of surface ``hot spots'' in a variety of engineering devices with heat transfer. Eventually, the size and location of the slit are seen to be an additional parameter that can be used to control the fluid flow structures behind rib turbulators.

  13. Comment on 'Biphoton double-slit experiment'

    SciTech Connect

    Oriols, X.

    2005-01-01

    In a recent paper [Phys. Rev. A 68, 033803 (2003)] experimental results on a double-slit configuration with two entangled bosons are presented. The authors argue that their data contradicts the de Broglie-Bohm interpretation of quantum mechanics. In this Comment we show that this conclusion is incorrect.

  14. Emittance formula for slits and pepper-pot measurement

    SciTech Connect

    Zhang, M.

    1996-10-01

    In this note, a rigid formula for slits and pepper-pot emittance measurement is derived. The derivation is based on the one- dimensional slit measurement setup. A mathematical generalization of the slit emittance formula to the pepper-pot measurement is discussed.

  15. Measuring Slit Width and Separation in a Diffraction Experiment

    ERIC Educational Resources Information Center

    Gan, K. K.; Law, A. T.

    2009-01-01

    We present a procedure for measuring slit width and separation in single- and double-slit diffraction experiments. Intensity spectra of diffracted laser light are measured with an optical sensor (PIN diode). Slit widths and separations are extracted by fitting to the measured spectra. We present a simple fitting procedure to account for the…

  16. Polarization dependent color switching by extra-ordinary transmission in H-slit plasmonic metasurface

    SciTech Connect

    Mandal, P.; Anantha Ramakrishna, S.; Patil, Raj; Venu Gopal, Achanta

    2013-12-14

    An array of H-shaped subwavelength slits in a plasmonic film has a polarization dependent extra-ordinary transmission due to shape anisotropy. Non-overlapping extra-ordinary transmission bands for the orthogonal linear polarization states of the input light are used to demonstrate a polarization dependent color switch. The fabricated array of submicron sized H-slits on a gold film displayed two transmission bands for the linear x- and y-polarized light at visible (650–850 nm) and near-infra-red (1150–1450 nm) bands, respectively. The relative transmitted light in these two bands can be controlled by changing the linear polarization state of the input radiation from 0° to 90°.

  17. Development and Preliminary Testing of a High Precision Long Stroke Slit Change Mechanism for the SPICE Instrument

    NASA Technical Reports Server (NTRS)

    Paciotti, Gabriel; Humphries, Martin; Rottmeier, Fabrice; Blecha, Luc

    2014-01-01

    In the frame of ESA's Solar Orbiter scientific mission, Almatech has been selected to design, develop and test the Slit Change Mechanism of the SPICE (SPectral Imaging of the Coronal Environment) instrument. In order to guaranty optical cleanliness level while fulfilling stringent positioning accuracies and repeatability requirements for slit positioning in the optical path of the instrument, a linear guiding system based on a double flexible blade arrangement has been selected. The four different slits to be used for the SPICE instrument resulted in a total stroke of 16.5 mm in this linear slit changer arrangement. The combination of long stroke and high precision positioning requirements has been identified as the main design challenge to be validated through breadboard models testing. This paper presents the development of SPICE's Slit Change Mechanism (SCM) and the two-step validation tests successfully performed on breadboard models of its flexible blade support system. The validation test results have demonstrated the full adequacy of the flexible blade guiding system implemented in SPICE's Slit Change Mechanism in a stand-alone configuration. Further breadboard test results, studying the influence of the compliant connection to the SCM linear actuator on an enhanced flexible guiding system design have shown significant enhancements in the positioning accuracy and repeatability of the selected flexible guiding system. Preliminary evaluation of the linear actuator design, including a detailed tolerance analyses, has shown the suitability of this satellite roller screw based mechanism for the actuation of the tested flexible guiding system and compliant connection. The presented development and preliminary testing of the high-precision long-stroke Slit Change Mechanism for the SPICE Instrument are considered fully successful such that future tests considering the full Slit Change Mechanism can be performed, with the gained confidence, directly on a

  18. Axial ultrasound B-scans of the entire eye with a 20-MHz linear array: correction of crystalline lens phase aberration by applying Fermat's principle.

    PubMed

    Mateo, Tony; Chang, Alexandre; Mofid, Yassine; Pisella, Pierre-Jean; Ossant, Frederic

    2014-11-01

    In ophthalmic ultrasonography the crystalline lens is known to be the main source of phase aberration, causing a significant decrease in resolution and distortion effects on axial B-scans. This paper proposes a computationally efficient method to correct the phase aberration arising from the crystalline lens, including refraction effects using a bending ray tracing approach based on Fermat's principle. This method is used as a basis to perform eye-adapted beamforming (BF), with appropriate focusing delays for a 128-element 20-MHz linear array in both emission and reception. Implementation was achieved on an in-house developed experimental ultrasound scanning device, the ECODERM. The proposed BF was tested in vitro by imaging a wire phantom through an eye phantom consisting of a synthetic gelatin lens anatomically set up in an appropriate liquid (turpentine) to approach the in vivo velocity ratio. Both extremes of accommodation shapes of the human crystalline lens were investigated. The performance of the developed BF was evaluated in relation to that in homogeneous medium and compared to a conventional delay-and-sum (DAS) BF and a second adapted BF which was simplified to ignore the lens refraction. Global expectations provided by our method with the transducer array are reviewed by an analysis quantifying both image quality and spatial fidelity, as well as the detrimental effects of a crystalline lens in conventional reconstruction. Compared to conventional array imaging, the results indicated a two-fold improvement in the lateral resolution, greater sensitivity and a considerable reduction of spatial distortions that were sufficient to envisage reliable biometry directly in B-mode, especially phakometry. PMID:24988589

  19. [Remote Slit Lamp Microscope Consultation System Based on Web].

    PubMed

    Chen, Junfa; Zhuo, Yong; Liu, Zuguo; Chen, Yanping

    2015-11-01

    To realize the remote operation of the slit lamp microscope for department of ophthalmology consultation, and visual display the real-time status of remote slit lamp microscope, a remote slit lamp microscope consultation system based on B/S structure is designed and implemented. Through framing the slit lamp microscope on the website system, the realtime acquisition and transmission of remote control and image data is realized. The three dimensional model of the slit lamp microscope is established and rendered on the web by using WebGL technology. The practical application results can well show the real-time interactive of the remote consultation system. PMID:27066677

  20. Reduced expression of Slit2 in renal cell carcinoma.

    PubMed

    Ma, Wei-Jie; Zhou, Yu; Lu, Dan; Dong, Dong; Tian, Xiao-Jun; Wen, Jie-Xi; Zhang, Jun

    2014-01-01

    Slit2, initially identified as an important axon guidance molecule in the nervous system, was suggested to be involved in multiple cellular processes. Recently, Slit2 was reported to function as a potential tumor suppressor in diverse tumors. In this study, we systematically analyzed the expression level of Slit2 in renal cell carcinoma. Compared to paired adjacent non-malignant tissues, both Slit2 mRNA and protein expression were significantly down-regulated in renal cell carcinoma (RCC). Methylation-specific PCR showed that Slit2 promoter was methylated in two renal carcinoma cell lines. Pharmacologic demethylation dramatically induced Slit2 expression in cancer cell lines with weak expression of Slit2. Besides, bisulfite genomic sequencing confirmed that dense methylation existed in Slit2 promoter. Furthermore, in paired RCC samples, Slit2 methylation was observed in 8 out of 38 patients (21.1 %), which was well correlated with the down-regulation of Slit2 in RCC. Therefore, Slit2 may also be a potential tumor suppressor in RCC, which is down-regulated in RCC partially due to promoter methylation.

  1. Self Interference of Single Electrodynamic Particle in Double Slit

    NASA Astrophysics Data System (ADS)

    Zheng-Johansson, J. X.

    2013-12-01

    It is by the long established fact in experiment and theory that electromagnetic waves, here as one component of an IED particle, passing a double slit will undergo self inference each, producing at a detector plane fringed intensities. The wave generating point charge of a zero rest mass, as the other component of the particle, is maintained a constant energy and speed by a repeated radiation reabsorption/reemission scheme, and in turn steered in direction in its linear motion by the reflected radiation field, and will thereby travel to the detector along (one of) the optical path(s) of the waves leading to a bright interference fringe. We elucidate the process formally based on first principles solutions for the IED particle and known principles for wave-matter interaction.

  2. Slit2/Robo1 signaling in glioma migration and invasion.

    PubMed

    Xu, Yun; Li, Wen-Liang; Fu, Li; Gu, Feng; Ma, Yong-Jie

    2010-12-01

    Slit2/Robo1 is a conserved ligand-receptor system, which greatly affects the distribution, migration, axon guidance and branching of neuron cells. Slit2 and its transmembrane receptor Robo1 have different distribution patterns in gliomas. The expression of Slit2 is at very low levels in pilocytic astrocytoma, fibrillary astrocytoma and glioblastoma, while Robo1 is highly expressed in different grades of gliomas at both mRNA and protein levels. Acquisition of insidious invasiveness by malignant glioma cells involves multiple genetic alterations in signaling pathways. Although the specific mechanisms of tumor-suppressive effect of Slit2/Robo1 have not been elucidated, it has been proved that Slit2/Robo1 signaling inhibits glioma cell migration and invasion by inactivation of Cdc42-GTP. With the research development on the molecular mechanisms of Slit2/Robo1 signaling in glioma invasion and migration, Slit2/Robo1 signaling may become a potential target for glioma prevention and treatment.

  3. Double-slit experiment in momentum space

    NASA Astrophysics Data System (ADS)

    Ivanov, I. P.; Seipt, D.; Surzhykov, A.; Fritzsche, S.

    2016-08-01

    Young's classic double-slit experiment demonstrates the reality of interference when waves and particles travel simultaneously along two different spatial paths. Here, we propose a double-slit experiment in momentum space, realized in the free-space elastic scattering of vortex electrons. We show that this process proceeds along two paths in momentum space, which are well localized and well separated from each other. For such vortex beams, the (plane-wave) amplitudes along the two paths acquire adjustable phase shifts and produce interference fringes in the final angular distribution. We argue that this experiment can be realized with the present-day technology. We show that it gives experimental access to the Coulomb phase, a quantity which plays an important role in all charged particle scattering but which usual scattering experiments are insensitive to.

  4. Double-slit experiments with microwave billiards.

    PubMed

    Bittner, S; Dietz, B; Miski-Oglu, M; Iriarte, P Oria; Richter, A; Schäfer, F

    2011-07-01

    Single and double-slit experiments are performed with two microwave billiards with the shapes of a rectangle and a quarter stadium, respectively. The classical dynamics of the former is regular, whereas that of the latter is chaotic. Microwaves can leave the billiards via slits in the boundary, forming interference patterns on a screen. The aim is to determine the effect of the billiard dynamics on their structure. For this the development of a method for the construction of a directed wave packet by means of an array of multiple antennas was crucial. The interference patterns show a sensitive dependence not only on the billiard dynamics but also on the initial position and direction of the wave packet.

  5. Third order optical non-linear (Z-scan), birefringence, photoluminescence, mechanical and etching studies on melaminium levulinate monohydrate (MLM) single crystal for optical device applications

    NASA Astrophysics Data System (ADS)

    Sivakumar, N.; Anbalagan, G.

    2016-10-01

    Z-scan studies on the grown crystal was investigated by diode-pumped Nd; YAG laser. Nonlinear refractive index (n2) and third-order nonlinear optical susceptibility (χ3) values of MLM were found to be -1.0 × 10-8 cm2/W and 1.36 × 10-6 esu respectively. Powder X-ray diffraction analysis depicted that the crystal belongs to monoclinic system with space group P21/c. Birefringence study revealed the optical dispersion behavior of MLM crystal. Linear refractive index on (10-1) plane was measured by prism coupling technique and was estimated to be 1.4705. Hardness study was carried out along three different planes which exhibit hardness anisotropy of 41.11%. Meyer's index values of the grown crystal for the (10-1), (010) and (111) planes were found to be 2.39, 2.61 and 2.04 respectively. Etching studies on the prominent (10-1) growth plane was explained by two dimensional layer growth mechanisms. Photoluminescence study was performed on MLM crystal to explore its efficacy towards optical device fabrications.

  6. Structure and functional relevance of the Slit2 homodimerization domain.

    PubMed

    Seiradake, Elena; von Philipsborn, Anne C; Henry, Maud; Fritz, Martin; Lortat-Jacob, Hugues; Jamin, Marc; Hemrika, Wieger; Bastmeyer, Martin; Cusack, Stephen; McCarthy, Andrew A

    2009-07-01

    Slit proteins are secreted ligands that interact with the Roundabout (Robo) receptors to provide important guidance cues in neuronal and vascular development. Slit-Robo signalling is mediated by an interaction between the second Slit domain and the first Robo domain, as well as being dependent on heparan sulphate. In an effort to understand the role of the other Slit domains in signalling, we determined the crystal structure of the fourth Slit2 domain (D4) and examined the effects of various Slit2 constructs on chick retinal ganglion cell axons. Slit2 D4 forms a homodimer using the conserved residues on its concave face, and can also bind to heparan sulphate. We observed that Slit2 D4 frequently results in growth cones with collapsed lamellipodia and that this effect can be inhibited by exogenously added heparan sulphate. Our results show that Slit2 D4-heparan sulphate binding contributes to a Slit-Robo signalling mechanism more intricate than previously thought.

  7. Epigenetic inactivation of SLIT2 in human hepatocellular carcinomas.

    PubMed

    Jin, Jie; You, Haiyan; Yu, Bin; Deng, Yun; Tang, Ning; Yao, Genfu; Shu, Huiqun; Yang, Shengli; Qin, Wenxin

    2009-01-30

    Recent findings have shown that SLIT2 appears to function as a novel tumor suppressor gene. In addition, hypermethylation of its promoter region has been detected in various cancers, including breast and lung cancer, colorectal carcinoma, and gliomas. Here, we report for the first time that there is epigenetic silencing of SLIT2 in human hepatocellular carcinoma (HCC). Downregulation of SLIT2 was detected in 6 of 8 (75%) HCC cell lines by quantitative real-time RT-PCR (qRT-PCR), and the downregulation of SLIT2 was generally dependent on the degree of methylation at the promoter region. Furthermore, expression of SLIT2 was restored in relatively low-expressing cell lines after treatment with 5-aza-2-deoxycytidine (5-Aza-dC). Downregulation of SLIT2 expression was also detected in 45 of 54 primary HCC samples (83.3%), and the decrease in expression was significantly correlated with CpG island hypermethylation. This decrease of SLIT2 expression was also associated with lymph node metastasis in HCC. Moreover, overexpression of SLIT2 in SMMC-7721 cells induced by recombinant adenovirus suppressed cell growth, migration, and invasion, These results suggest that epigenetic inactivation of SLIT2 in HCC may be important in the development and progression of HCC. Thus, SLIT2 may be useful as a therapeutic target in the treatment of HCC.

  8. Boltzmann-Shannon entropy and the double-slit experiment

    NASA Astrophysics Data System (ADS)

    Norwich, Kenneth H.

    2016-11-01

    We study the Boltzmann-Shannon entropy lost (information gained) by the observer in a double-slit experiment when the slit taken by a photon is known, and when the corresponding entropy gained by the photon at the level of the screen can be calculated. Using a Gedanken experiment involving infinitesimal slits and a distant cylindrical screen, entropy values assume a very simple form. The entropy changes (at the slit and screen) are found to be equal in magnitude and opposite in sign, and correspond to the minimum change permitted by Heisenberg's Uncertainty Principle. Moreover, when welcher Weg information is knowable a priori, we see that the "cost" of this information (knowing which slit is taken) is reversion to a single slit pattern.

  9. Approximate model for surface-plasmon generation at slit apertures.

    PubMed

    Lalanne, P; Hugonin, J P; Rodier, J C

    2006-07-01

    We present a semianalytical model that quantitatively predicts the scattering of light by a single subwavelength slit in a thick metal screen. In contrast to previous theoretical works related to the transmission properties of the slit, the analysis emphasizes the generation of surface plasmons at the slit apertures. The model relies on a two-stage scattering mechanism, a purely geometric diffraction problem in the immediate vicinity of the slit aperture followed by the launching of a bounded surface-plasmon wave on the flat interfaces surrounding the aperture. By comparison with a full electromagnetic treatment, the model is shown to provide accurate formulas for the plasmonic generation strength coefficients, even for metals with a low conductivity. Limitations are outlined for large slit widths (>lambda) or oblique incidence (>30 degrees ) when the slit is illuminated by a plane wave. PMID:16783423

  10. Resolution criteria in double-slit microscopic imaging experiments

    PubMed Central

    You, Shangting; Kuang, Cuifang; Zhang, Baile

    2016-01-01

    Double-slit imaging is widely used for verifying the resolution of high-resolution and super-resolution microscopies. However, due to the fabrication limits, the slit width is generally non-negligible, which can affect the claimed resolution. In this paper we theoretically calculate the electromagnetic field distribution inside and near the metallic double slit using waveguide mode expansion method, and acquire the far-field image by vectorial Fourier optics. We find that the slit width has minimal influence when the illuminating light is polarized parallel to the slits. In this case, the claimed resolution should be based on the center-to-center distance of the double-slit. PMID:27640808

  11. Resolution criteria in double-slit microscopic imaging experiments.

    PubMed

    You, Shangting; Kuang, Cuifang; Zhang, Baile

    2016-01-01

    Double-slit imaging is widely used for verifying the resolution of high-resolution and super-resolution microscopies. However, due to the fabrication limits, the slit width is generally non-negligible, which can affect the claimed resolution. In this paper we theoretically calculate the electromagnetic field distribution inside and near the metallic double slit using waveguide mode expansion method, and acquire the far-field image by vectorial Fourier optics. We find that the slit width has minimal influence when the illuminating light is polarized parallel to the slits. In this case, the claimed resolution should be based on the center-to-center distance of the double-slit. PMID:27640808

  12. Note: Compact, two-dimension translatable slit aperture

    NASA Astrophysics Data System (ADS)

    Gao, R. S.; Thornberry, T. D.; McLaughlin, R. J.; Fahey, D. W.

    2013-11-01

    A compact, light-weight, two-dimension translatable slit aperture is described. The slit dimensions are scalable, allowing for wide application. With all metal construction, the device would be suitable for high temperature degassing and vacuum compatible. Alternatively, the main structure may be printed using a 3D printer for rapid prototyping and/or lighter weight. The precision of the slit movement is 0.014 mm.

  13. Transmission resonances of metallic compound gratings with subwavelength slits.

    PubMed

    Skigin, Diana C; Depine, Ricardo A

    2005-11-18

    Transmission metallic gratings with subwavelength slits are known to produce enhanced transmitted intensity for certain resonant wavelengths. One of the mechanisms that produce these resonances is the excitation of waveguide modes inside the slits. We show that by adding slits to the period, the transmission maxima are widened and, simultaneously, this generates phase resonances that appear as sharp dips in the transmission response. These resonances are characterized by a significant enhancement of the interior field.

  14. Approximation theory for boundary layer suction through individual slits

    NASA Technical Reports Server (NTRS)

    Walz, A.

    1979-01-01

    The basic concepts of influencing boundary layers are summarized, especially the prevention of flow detachment and the reduction of frictional resistance. A mathematical analysis of suction through a slit is presented with two parameters, for thickness and for shape of the boundary layer, being introduced to specify the flow's velocity profile behind the slit. An approximation of the shape parameter produces a useful formula, which can be used to determine the most favorable position of the slit. An aerodynamic example is given.

  15. Allvar Gullstrand and the slit lamp 1911.

    PubMed

    Timoney, P J; Breathnach, C S

    2013-06-01

    The Swedish ophthalmologist and self-taught mathematician Allvar Gullstrand (1862-1930) invented the slit lamp to illuminate the anterior of the eye. With its rectangular beam of very bright light, he studied the structure of the cornea and the function of the lens. His dioptric investigations showed that, as well as the extracapsular mechanism described by Helmholtz, changes in the substance of the lens, that he termed intracapsular, also contribute to accommodation. However, his invention has been appropriated by clinical ophthalmologists and is now routinely used in examination of the eye. PMID:23264115

  16. Multi-slit mask fabrication on spherical electroformed shell substrates

    NASA Astrophysics Data System (ADS)

    O'Brien, Thomas P.; Eastman, Jason D.

    2006-06-01

    We discuss the application of modern precision electroforming technology to the fabrication of multi-slit masks used for multi-object spectroscopy. Electroforming technology is capable of producing very accurate compound curved thin metal shells using nickel or nickel-cobalt material. The curved slit masks can be fabricated to conform to a curved focal surface of spherical, conic, or arbitrary shape. A variety of optical coatings including gold and extremely low reflectivity copper oxide can be applied to the electroformed mask substrate prior to cutting slits. Precise rectangular slits and apertures of arbitrary shape are readily machined in the nickel materials using a three axis YAG laser machining system.

  17. Modifications to improve entrance slit thermal stability for grasshopper monochromators

    NASA Astrophysics Data System (ADS)

    Wallace, Daniel J.; Rogers, Gregory C.; Crossley, Sherry L.

    1994-08-01

    As new monochromators are designed for high-flux storage rings, computer modeling and thermal engineering can be done to process increased heat loads and achieve mechanical stability. Several older monochromators, such as the Mark 2 and Mark 5 Grasshopper monochromators, which were designed in 1974, have thermal instabilities in their entrance slit mechanisms. The Grasshoppers operating with narrow slits experience closure of the entrance slit from thermal expansion. In extreme cases, the thermal expansion of the precision components has caused permanent mechanical damage, leaving the slit uncalibrated and/or inoperable. For the Mark 2 and Mark 5 Grasshopper monochromators at the Synchrotron Radiation Center, the original 440 stainless steel entrance slit jaws were retrofitted with an Invar (low expansion Fe, Ni alloy) slit jaw. To transfer the heat from the critical components, two flexible heat straps of Cu were attached. These changes allow safe operation with a 10 μm entrance slit width where the previous limit was 30 μm. After an initial 2 min equilibration, the slit remains stable to 10%, with 100 mA of beam current. Additional improvements in slit thermal stability are planned for a third Grasshopper.

  18. Plasmon-assisted two-slit transmission: Young's experiment revisited.

    PubMed

    Schouten, H F; Kuzmin, N; Dubois, G; Visser, T D; Gbur, G; Alkemade, P F A; Blok, H; Hooft, G W 't; Lenstra, D; Eliel, E R

    2005-02-11

    We present an experimental and theoretical study of the optical transmission of a thin metal screen perforated by two subwavelength slits, separated by many optical wavelengths. The total intensity of the far-field double-slit pattern is shown to be reduced or enhanced as a function of the wavelength of the incident light beam. This modulation is attributed to an interference phenomenon at each of the slits, instead of at the detector. The interference arises as a consequence of the excitation of surface plasmons propagating from one slit to the other.

  19. 6 Mcps photon-counting X-ray computed tomography system using a 25 mm/s-scan linear LSO-MPPC detector and its application to gadolinium imaging

    NASA Astrophysics Data System (ADS)

    Sato, Eiichi; Oda, Yasuyuki; Abudurexiti, Abulajiang; Hagiwara, Osahiko; Matsukiyo, Hiroshi; Osawa, Akihiro; Enomoto, Toshiyuki; Watanabe, Manabu; Kusachi, Shinya; Sugimura, Shigeaki; Endo, Haruyuki; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun

    2011-12-01

    6 Mcps photon counting was carried out using a detector consisting of a 1.0 mm-thick LSO [Lu 2(SiO 4)O] single-crystal scintillator and an MPPC (multipixel photon counter) module in an X-ray computed tomography (CT) system. The maximum count rate was 6 Mcps (mega counts per second) at a tube voltage of 100 kV and a tube current of 0.91 mA. Next, a photon-counting X-ray CT system consists of an X-ray generator, a turntable, a scan stage, a two-stage controller, the LSO-MPPC detector, a counter card (CC), and a personal computer (PC). Tomography is accomplished by repeated linear scans and rotations of an object, and projection curves of the object are obtained by the linear scan with a scan velocity of 25 mm/s. The pulses of the event signal from the module are counted by the CC in conjunction with the PC. The exposure time for obtaining a tomogram was 600 s at a scan step of 0.5 mm and a rotation step of 1.0°, and photon-counting CT was accomplished using gadolinium-based contrast media.

  20. On time and space double-slit experiments

    NASA Astrophysics Data System (ADS)

    Bauer, M.

    2014-11-01

    Unlike the usual interference experiment with two slits separated in space, a time double-slit experiment uses the equivalent of a single slit covered by a shutter that is opened and closed and then quickly opened and closed again. Such experiments have recently been performed, providing further confirmation of wave-particle duality. In either type of experiment, the wave function beyond the slit(s) initially has two peaks that then spread and interfere. This article derives the results of these experiments in a schematic, but analytic solution of the time-dependent Schrödinger equation with appropriate initial conditions. In the space double-slit case, in addition to the transverse interference pattern, the time evolution at a fixed position exhibits an oscillating transient behavior similar to that obtained in the time double-slit experiment. Finally, the schematic model also reproduces the observed progressive visibility of the interference pattern obtained as a movable mask is displaced in front of the double-slit.

  1. A virtual slit for atom optics and nanolithography

    NASA Astrophysics Data System (ADS)

    Chu, A. P.; Berggren, K. K.; Johnson, K. S.; Prentiss, M. G.

    1996-06-01

    We propose a simple `virtual slit' for atoms based on the position- and velocity-dependent optical pumping of atoms into an undetected internal state. We show how this slit can be used as a nanometre scale, high-contrast tool for atom lithography as well as a subrecoil collimator for atomic beams.

  2. Single-Slit Diffraction and the Uncertainty Principle

    ERIC Educational Resources Information Center

    Rioux, Frank

    2005-01-01

    A theoretical analysis of single-slit diffraction based on the Fourier transform between coordinate and momentum space is presented. The transform between position and momentum is used to illuminate the intimate relationship between single-slit diffraction and uncertainty principle.

  3. Mobilizing slit lamp to the field: A new affordable solution.

    PubMed

    Farooqui, Javed Hussain; Jorgenson, Richard; Gomaa, Ahmed

    2015-11-01

    We are describing a simple and affordable design to pack and carry the slit lamp to the field. Orbis staff working on the Flying Eye Hospital (FEH) developed this design to facilitate mobilization of the slit lamp to the field during various FEH programs. The solution involves using a big toolbox, a central plywood apparatus, and foam. These supplies were cut to measure and used to support the slit lamp after being fitted snuggly in the box. This design allows easy and safe mobilization of the slit lamp to remote places. It was developed with the efficient use of space in mind and it can be easily reproduced in developing countries using same or similar supplies. Mobilizing slit lamp will be of great help for staff and institutes doing regular outreach clinical work.

  4. Mobilizing slit lamp to the field: A new affordable solution

    PubMed Central

    Farooqui, Javed Hussain; Jorgenson, Richard; Gomaa, Ahmed

    2015-01-01

    We are describing a simple and affordable design to pack and carry the slit lamp to the field. Orbis staff working on the Flying Eye Hospital (FEH) developed this design to facilitate mobilization of the slit lamp to the field during various FEH programs. The solution involves using a big toolbox, a central plywood apparatus, and foam. These supplies were cut to measure and used to support the slit lamp after being fitted snuggly in the box. This design allows easy and safe mobilization of the slit lamp to remote places. It was developed with the efficient use of space in mind and it can be easily reproduced in developing countries using same or similar supplies. Mobilizing slit lamp will be of great help for staff and institutes doing regular outreach clinical work. PMID:26669342

  5. Stowage and Deployment of Slit Tube Booms

    NASA Technical Reports Server (NTRS)

    Adams, Larry (Inventor); Turse, Dana (Inventor); Richardson, Doug (Inventor)

    2016-01-01

    A system comprising a boom having a first end, a longitudinal length, and a slit that extends along the longitudinal length of the boom; a drum having an elliptic cross section and a longitudinal length; an attachment mechanism coupled with the first end of the boom and the drum such that the boom and the drum are substantially perpendicular relative to one another; an inner shaft having a longitudinal length, the inner shaft disposed within the drum, the longitudinal length of the inner shaft is aligned substantially parallel with the longitudinal length of the drum, the inner shaft at least partially rotatable relative to the drum, and the inner shaft is at least partially rotatable with the drum; and at least two cords coupled with the inner shaft and portions of the boom near the first end of the boom.

  6. White beam slits and pink beam slits for the hard x-ray nanoprobe beamline at the Advanced Photon Source.

    SciTech Connect

    Benson, C.; Jaski, Y.; Maser, J.; Powers, T.; Schmidt, O.; Rossi, E.

    2007-01-01

    A new type of slit has been designed for use in the hard x-ray nanoprobe beamline at the Advanced Photon Source (APS). The design incorporates monolithic GlidCop slit bodies mounted to commercially available x-y drive systems. Long, tapered apertures with adjacent water-cooling channels intercept the x-ray beam, removing the high heat load produced by two collinear APS undulators. The apertures are L-shaped and provide both horizontal and vertical slits. The beam-defining edges, positioned at the end of the tapered surfaces, consist of two sets of tungsten blades. These blades produce an exit beam with sharp corners and assure a clean cut-off for the white beam edges. The slit assembly is designed to allow overlap of the slit edges to stop the beam. The white beam slit design accommodates 3100 W of total power with a peak power density of 763 W/mm2. The pink beam slit design accommodates 400 W of total power with a peak power density of 180 W/mm2. Detailed thermal analyses were performed to verify the slits accuracy under full beam loading. The new concept allows beamline operations to 180 mA with a simplified design approach.

  7. White Beam Slits and Pink Beam Slits for the Hard X-ray Nanoprobe Beamline at the Advanced Photon Source

    SciTech Connect

    Benson, C.; Jaski, Y.; Powers, T.; Schmidt, O.; Rossi, E.; Maser, J.

    2007-01-19

    A new type of slit has been designed for use in the hard x-ray nanoprobe beamline at the Advanced Photon Source (APS). The design incorporates monolithic GlidCop slit bodies mounted to commercially available x-y drive systems. Long, tapered apertures with adjacent water-cooling channels intercept the x-ray beam, removing the high heat load produced by two collinear APS undulators. The apertures are L-shaped and provide both horizontal and vertical slits. The beam-defining edges, positioned at the end of the tapered surfaces, consist of two sets of tungsten blades. These blades produce an exit beam with sharp corners and assure a clean cut-off for the white beam edges. The slit assembly is designed to allow overlap of the slit edges to stop the beam.The white beam slit design accommodates 3100 W of total power with a peak power density of 763 W/mm2. The pink beam slit design accommodates 400 W of total power with a peak power density of 180 W/mm2. Detailed thermal analyses were performed to verify the slits' accuracy under full beam loading. The new concept allows beamline operations to 180 mA with a simplified design approach.

  8. Fibroblasts secrete Slit2 to inhibit fibrocyte differentiation and fibrosis.

    PubMed

    Pilling, Darrell; Zheng, Zhichao; Vakil, Varsha; Gomer, Richard H

    2014-12-23

    Monocytes leave the blood and enter tissues. In healing wounds and fibrotic lesions, some of the monocytes differentiate into fibroblast-like cells called fibrocytes. In healthy tissues, even though monocytes enter the tissue, for unknown reasons, very few monocytes differentiate into fibrocytes. In this report, we show that fibroblasts from healthy human tissues secrete the neuronal guidance protein Slit2 and that Slit2 inhibits human fibrocyte differentiation. In mice, injections of Slit2 inhibit bleomycin-induced lung fibrosis. In lung tissue from pulmonary fibrosis patients with relatively normal lung function, Slit2 has a widespread distribution whereas, in patients with advanced disease, there is less Slit2 in the fibrotic lesions. These data may explain why fibrocytes are rarely observed in healthy tissues, may suggest that the relative levels of Slit2 present in healthy tissue and at sites of fibrosis may have a significant effect on the decision of monocytes to differentiate into fibrocytes, and may indicate that modulating Slit2 signaling may be useful as a therapeutic for fibrosis.

  9. A microbeam slit system for high beam currents

    NASA Astrophysics Data System (ADS)

    Vallentin, T.; Moser, M.; Eschbaumer, S.; Greubel, C.; Haase, T.; Reichart, P.; Rösch, T.; Dollinger, G.

    2015-04-01

    A new microbeam slit system for high beam currents of 10 μA was built up to improve the brightness transport of a proton beam with a kinetic energy of up to 25 MeV into the microprobe SNAKE. The new slit system features a position accuracy of less than 1 μm under normal operating conditions and less than 2 μm if the beam is switched on and off. The thermal management with a powerful watercooling and potential-free thermocouple feedback controlled heating cables is optimized for constant slit aperture at thermal power input of up to 250 W. The transparent zone is optimized to 0.7 μm due to the use of tungsten formed to a cylindrical surface with a radius r = 100 mm and mechanically lapped surface to minimize small angle scattering effects and to minimize the number of ions passing the slits with low energy loss. Electrical isolation of the slit tip enables slit current monitoring, e.g. for tandem accelerator feedback control. With the ability to transport up to 10 μA of protons with the new microslit system, the brightness Bexp transported into the microprobe was increased by a factor of 2 compared to low current injection using the old slit system.

  10. Ultrabroadband absorber using a deep metallic grating with narrow slits

    NASA Astrophysics Data System (ADS)

    Liao, Yan-Lin; Zhao, Yan

    2015-01-01

    We report an ultrabroadband absorber using a deep metallic grating with narrow slits in the infrared regime. In this absorber, the ultrabroadband electromagnetic wave has been perfectly transmitted through the vacuum-grating interface due to the plasmonic Brewster angle effect, and its energy can attenuate effectively through the slits because of the enhanced electric field inside the slits. In addition, simulation results show that this ultrabroadband absorber works over a narrow angle range which is a very important feature of directional thermal source.

  11. Momentum exchange in the electron double-slit experiment

    NASA Astrophysics Data System (ADS)

    Batelaan, Herman; Jones, Eric; Cheng-Wei Huang, Wayne; Bach, Roger

    2016-03-01

    We provide support for the claim that momentum is conserved for individual events in the electron double slit experiment. The natural consequence is that a physical mechanism is responsible for this momentum exchange, but that even if the fundamental mechanism is known for electron crystal diffraction and the Kapitza-Dirac effect, it is unknown for electron diffraction from nano-fabricated double slits. Work towards a proposed explanation in terms of particle trajectories affected by a vacuum field is discussed. The contentious use of trajectories is discussed within the context of oil droplet analogues of double slit diffraction.

  12. Amontillado is required for Drosophila Slit processing and for tendon-mediated muscle patterning

    PubMed Central

    Ordan, Elly

    2016-01-01

    ABSTRACT Slit cleavage into N-terminal and C-terminal polypeptides is essential for restricting the range of Slit activity. Although the Slit cleavage site has been characterized previously and is evolutionally conserved, the identity of the protease that cleaves Slit remains elusive. Our previous analysis indicated that Slit cleavage is essential to immobilize the active Slit-N at the tendon cell surfaces, mediating the arrest of muscle elongation. In an attempt to identify the protease required for Slit cleavage we performed an RNAi-based assay in the ectoderm and followed the process of elongation of the lateral transverse muscles toward tendon cells. The screen led to the identification of the Drosophila homolog of pheromone convertase 2 (PC2), Amontillado (Amon), as an essential protease for Slit cleavage. Further analysis indicated that Slit mobility on SDS polyacrylamide gel electrophoresis (SDS-PAGE) is slightly up-shifted in amon mutants, and its conventional cleavage into the Slit-N and Slit-C polypeptides is attenuated. Consistent with the requirement for amon to promote Slit cleavage and membrane immobilization of Slit-N, the muscle phenotype of amon mutant embryos was rescued by co-expressing a membrane-bound form of full-length Slit lacking the cleavage site and knocked into the slit locus. The identification of a novel protease component essential for Slit processing may represent an additional regulatory step in the Slit signaling pathway. PMID:27628033

  13. Semiclassical simulation of the double-slit experiments with single photons

    NASA Astrophysics Data System (ADS)

    Rashkovskiy, Sergey A.

    2015-12-01

    Many quantum phenomena, traditionally described by quantum electrodynamics, can be calculated within the framework of so-called semiclassical theory, in which atoms are described by the wave equations of quantum mechanics (Schrödinger, Dirac, etc.), while light is described by classical electrodynamics without quantization of the radiation. These phenomena include the photoelectric effect, the Compton effect, the Lamb shift, radiative effects, spontaneous emission, the Hanbury Brown and Twiss effect, etc. In this paper, I show that the double-slit experiment can also be calculated in detail in terms of semiclassical theory if we take into account the discrete (atomic) structure of matter. I show that the results of a semiclassical simulation of the "linear" double-slit experiment coincide with predictions of wave theory only for low-intensity light and for short exposure time, while stricter dependences exist for long-term exposure. The semiclassical theory is used for calculation of the "nonlinear" double-slit experiment with an intense laser beam in which multiphoton and tunnel excitation of atoms on a photographic plate occurs. The Born rule for light is derived from the semiclassical theory.

  14. Computed tomography with linear shift-invariant optical systems.

    PubMed

    Gureyev, Timur E; Nesterets, Yakov I; Pavlov, Konstantin M; Wilkins, Stephen W

    2007-08-01

    Optical systems capable of three-dimensional transmission imaging are considered; these systems employ a conventional tomographic setup with an added linear shift-invariant optical system between the sample and the detector. A theoretical analysis is presented of image formation and sample reconstruction in such systems, examples of which include diffraction tomography and phase-contrast tomography with the use of analyzer crystals. An example is introduced in which the image is obtained by scanning the beam along the line orthogonal to the optic axis and to the axis of rotation with a one-dimensional slit or grating parallel to the rotation axis. We show that under certain conditions the proposed system may allow quantitative local (region-of-interest) tomography.

  15. Long slit spectroscopy of NGC 5506

    NASA Technical Reports Server (NTRS)

    Stanga, R. M.; Maiolino, R.; Rodriguezespinosa, J. M.

    1993-01-01

    The galaxy NGC 5506 hosts an active nucleus, that presents characteristics that are intermediate between Sy1 and Sy2. We discuss long slit spectra of NGC 5506 in the ranges 4675-5475 A and 6300-7125 A, that were obtained at three different position angles, in Apr. 1991 at the WHT 4.2 m telescope. The peculiar kinematics of the emitting gas has already been observed by other researchers; following the model proposed by the other researchers, that the emitting gas is located in two cones, we determined the aperture of the cones. The data, moreover, support the hypothesis that the gas is receding from the nucleus. We modelled the intensity and the ratios of the emission lines, and verified that the active nucleus of NGC 5506 can be described as a Sy1 nucleus, with the UV-X source that is partially obscured to our line of sight. On the contrary, a good fraction of the interstellar gas of the galaxy is directly illuminated and photoionized by the central source. Our data show evidence of star formation close to the nucleus; we estimated the star formation rate, that is high with respect to 'normal' spirals, but not high enough to be comparable to star formation rates in a starburst galaxy.

  16. Springback Prediction on Slit-Ring Test

    NASA Astrophysics Data System (ADS)

    Chen, Xiao Ming; Shi, Ming F.; Ren, Feng; Xia, Z. Cedric

    2005-08-01

    Advanced high strength steels (AHSS) are increasingly being used in the automotive industry to reduce vehicle weight while improving vehicle crash performance. One of the concerns in manufacturing is springback control after stamping. Although computer simulation technologies have been successfully applied to predict stamping formability, they still face major challenges in springback prediction, particularly for AHSS. Springback analysis is very complicated and involves large deformation problems in the forming stage and mechanical multiplying effect during the elastic recovery after releasing a part from the die. Therefore, the predictions are very sensitive to the simulation parameters used. It is very critical in springback simulation to choose an appropriate material model, element formulation and contact algorithm. In this study, a springback benchmark test, the slit ring cup, is used in the springback simulation with commercially available finite element analysis (FEA) software, LS-DYNA. The sensitivity of seven simulation variables on springback predictions was investigated, and a set of parameters with stable simulation results was identified. Final simulations using the selected set of parameters were conducted on six different materials including two AHSS steels, two conventional high strength steels, one mild steel and an aluminum alloy. The simulation results are compared with experimental measurements for all six materials and a favorable result is achieved. Simulation errors as compared against test results falls within 10%.

  17. Corneal astigmatism measuring module for slit lamps

    NASA Astrophysics Data System (ADS)

    Ventura, L.; Riul, C.; Sousa, S. J. F.; DeGroote, J. G. S.; Rosa Filho, A. B.; Oliveira, G. C. D.

    2006-06-01

    We have developed an automatic keratometer module for slit lamps that provides automatic measurements of the radii of the corneal curvature. The system projects 72 light spots displayed in a precise circle at the examined cornea. The displacement and deformation of the reflected image of these light spots are analysed providing the keratometry. Measurements in the range of 26.8-75 D can be obtained and a self-calibration system has been specially designed in order to keep the system calibrated. Infrared LEDs indicate automatically which eye is being examined. Volunteer patients (492) have been submitted to the system and the results show that our system has a high correlation factor with the commercially available manual keratometers and the keratometry measurements from a topographer. Our developed system is 95% in agreement with the corneal topographer (Humphrey—Atlas 995 CZM) and the manual keratometer (Topcon OM-4). The system's nominal precision is 0.05 mm for the radii of curvature and 1° for the associated axis. This research has been supported by Fundação de Apoio à Pesquisa do Estado de São Paulo (FAPESP).

  18. THz transmission through cross metallic fractal slits by FDTD simulation

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoyan; Liu, Liming; Zhao, Guozhong; Zhang, Cunlin

    2011-08-01

    The transmission spectra of sub-wavelength cross metallic fractal slits in terahertz (THz) frequency region are presented by means of finite-difference-time-domain (FDTD) simulation. The transmission spectra with multiple pass bands and stop bands are observed. To understand the physical mechanism of the enhanced transmissions, we simulated the electric field distribution of THz radiation within the metallic slits at the resonance frequencies by the electromagnetic design software named CONCERTO. Further analysis reveals that the two transmission peaks in the low frequency is the local resonance of electric field of the two cross slit, respectively. The third transmission peak is the co-effect of the two level cross slits. Our simulation is helpful for the understanding of THz wave propagation and THz transmission through the cross metallic fractal structures. It is also useful for the development of THz photonic devices.

  19. Optical design of MWIR imaging spectrometer with a cold slit

    NASA Astrophysics Data System (ADS)

    Zhou, Shiyao; Wang, Yueming; Qian, Liqun; Yuan, Liyin; Wang, Jianyu

    2016-05-01

    MWIR imaging spectrometer is promising in detecting spectral signature of high temperature object such as jet steam, guided missile and explosive gas. This paper introduces an optical design of a MWIR imaging spectrometer with a cold slit sharply reducing the stray radiation from exterior environment and interior structure. The spectrometer is composed of a slit, a spherical prism as disperser, two concentric spheres and a correction lens. It has a real entrance pupil to match the objective and for setting the infrared cold shield near the slit and a real exit pupil to match the cold shield of the focal plane array (FPA). There are two cooled parts, one includes the aperture stop and slit, and the other is the exit pupil and the FPA with two specially positioned cooled shields. A detailed stray radiation analysis is represented which demonstrates the outstanding effect of this system in background radiation restraint.

  20. A Computational and Experimental Study of Slit Resonators

    NASA Technical Reports Server (NTRS)

    Tam, C. K. W.; Ju, H.; Jones, M. G.; Watson, W. R.; Parrott, T. L.

    2003-01-01

    Computational and experimental studies are carried out to offer validation of the results obtained from direct numerical simulation (DNS) of the flow and acoustic fields of slit resonators. The test cases include slits with 90-degree corners and slits with 45-degree bevel angle housed inside an acoustic impedance tube. Three slit widths are used. Six frequencies from 0.5 to 3.0 kHz are chosen. Good agreement is found between computed and measured reflection factors. In addition, incident sound waves having white noise spectrum and a prescribed pseudo-random noise spectrum are used in subsequent series of tests. The computed broadband results are again found to agree well with experimental data. It is believed the present results provide strong support that DNS can eventually be a useful and accurate prediction tool for liner aeroacoustics. The usage of DNS as a design tool is discussed and illustrated by a simple example.

  1. Spectral anomalies in Young's double-slit interference experiment.

    PubMed

    Pu, Jixiong; Cai, Chao; Nemoto, Shojiro

    2004-10-18

    We report a phenomenon of spectral anomalies in the interference field of Young's double-slit interference experiment. The potential applications of the spectral anomalies in the information encoding and information transmission in free space are also considered.

  2. Slit observations and empirical calculations for HII regions

    NASA Astrophysics Data System (ADS)

    Fernandes, I. F.; Gruenwald, R.; Viegas, S. M.

    2005-12-01

    When analysing HII regions, a possible source of systematic error on empirically derived quantities, such as the gas temperature and the chemical composition, is the limited size of the slit used for the observations. In order to evaluate this type of systematic error, we use the photoionization code AANGABA to create a virtual photoionized region and mimic the effect of a slit observation. A grid of models was built varying the ionizing radiation spectrum emitted by a central stellar cluster, as well as the gas abundance. The calculated line surface brightness was then used to simulate slit observations and to derive empirical parameters using the usual methods described in the literature. Depending on the fraction of the object covered by the slit, the empirically derived physical parameters and chemical composition can be different from those obtained from observations of the whole object. This effect is mainly dependent on the age of the ionizing stellar cluster. The low-ionization lines, which originate in the outer layers of the ionized gas, are more sensitive to the size of the area covered by the slit than the high-ionization forbidden lines or recombination lines, because these lines are mainly produced closer to the inner radius of the nebula. For a slit covering 50 per cent or less of the total area, the measured [OIII], [OII] and [OI] line intensities are less than 78, 62 and 58 per cent of the total intensity for a young HII region (t < 3 Myr); for older objects the effect due to the slit is less significant. Regarding the temperature indicator T[OIII], the slit effects are small (usually less than 5 per cent) because this temperature is derived from [OIII] high-ionization lines. On the other hand, for the abundance (and temperature) indicator R23, which depends also on the [OII] line, the slit effect is slightly higher. Therefore, the systematic error due to slit observations on the O abundance is low, being usually less than 10 per cent, except for

  3. Imaging Spectrometer Designs Utilizing Immersed Gratings With Accessible Entrance Slit

    DOEpatents

    Chrisp, Michael P.; Lerner, Scott A.

    2006-03-21

    A compact imaging spectrometer comprises an entrance slit, a catadioptric lens with a mirrored surface, a grating, and a detector array. The entrance slit directs light to the mirrored surface of the catadioptric lens; the mirrored surface reflects the light back through the lens to the grating. The grating receives the light from the catadioptric lens and diffracts the light to the lens away from the mirrored surface. The lens transmits the light and focuses it onto the detector array.

  4. [The coding correction of slit diffraction in Hadamard transform spectrometer].

    PubMed

    Li, Bo; Wang, Shu-Rong; Huang, Yu; Wang, Jun-Bo

    2013-08-01

    According to the principles of Hadamard transform spectrometer and the slit diffraction characteristics, the influence of spectrometer entrance slit diffraction of Hadamard transform spectrometer on the measurement result was analyzed, for the diffraction case, the Hadamard transform spectrometer instrument structure matrix was studied, and the Hadamard transform spectrometer encoding/decoding method was established. The analysis of incident spectral verified the correctness of the coding/ decoding. This method is very important for the high precision measurement of Hadamard transform spectrometer.

  5. Gouy phase and visibility in the double-slit experiment

    NASA Astrophysics Data System (ADS)

    Ferreira, C. J. S.; Marinho, L. S.; Brazil, T. B.; Cabral, L. A.; de Oliveira, J. G. G., Jr.; Sampaio, M. D. R.; da Paz, I. G.

    2015-11-01

    We study a matter wave double-slit experiment with unequal aperture widths in order to evaluate the effect of the Gouy phase on the visibility/predictability. While the predictability changes as one increases the width of one of the slits, the visibility receives a contribution from the Gouy phase at a specific point in the detection screen. Consequently such apparatus constitutes a simple device for measuring the Gouy phase of matter waves. We illustrate it numerically for neutrons.

  6. Young's double-slit experiment in photonic crystals

    SciTech Connect

    Zhang, Lei; Koschny, Thomas; Soukoulis, Costas M.

    2012-10-01

    We present an experimental and numerical study of the transmission of a photonic crystal perforated by two sub-wavelength slits, separated by two wavelengths.The experimental near-field image of the double-slit design of the photonic crystal shows an interference pattern, which is analogous to Young’s experiment. This interference arises as a consequence of the excitation of surface states of the photonic crystals and agrees very well with the simulations.

  7. Construction of pre-slit system of Chinese SONG spectrograph

    NASA Astrophysics Data System (ADS)

    Gao, Pengfei; Hu, Zhongwen; Dai, Songxin

    2015-10-01

    The pre-slit system of Chinese SONG spectrograph is a multi-function unit. The main function is to direct the incoming light from the coudé path to the entrance slit of the spectrograph. The specific functions includes maintaining exit pupil stable, fast guiding and telescope focus corrections. The original optics of this pre-slit system were designed by Aarhus University in Denmark. We built the system and designed the software for it. This system holds a guide/slit-viewing camera, a pupil-viewing camera, two tip-tilt mirrors and its tip-tilt controllers. So it includes two sets of the fast-steering mirror systems applied to image tracking and correction. When this image tracking and correction systems is running, the real-time software algorithm will be presented and simulated simultaneously. From the images taken with camera, a closed loop signals are generated for the tip-tilt mirror to correct image motion. When the camera exposure time is 25ms,the correcting frequency of slit imge tip-tilt motion is about 30Hz. The correcting frequency of pupil imge tip-tilt motion is about 1Hz. In addition, a temperature control system surrounding the spectrograph is necessary to keep spectrograph at a constant temperature. The test results shows that the error is about +/-0.005°C in 69.4 hours. The results prove that the pre-slit system of Chinese SONG spectrograph is effective and feasible.

  8. Influence of annealing on the linear and nonlinear optical properties of Mn doped ZnO thin films examined by z-scan technique in CW regime

    NASA Astrophysics Data System (ADS)

    Nagaraja, K. K.; Pramodini, S.; Poornesh, P.; Rao, Ashok; Nagaraja, H. S.

    2016-08-01

    We present the studies on the influence of annealing on the third-order nonlinear optical properties of RF magnetron sputtered manganese doped zinc oxide (MZO) thin films with different doping concentration. It is revealed that the incorporation of Mn into ZnO and annealing lead to prominent changes in the third order nonlinearity. Nonlinear optical measurements were carried out by employing the z-scan technique using a continuous wave (CW) Hesbnd Ne laser of 633 nm. The z-scan results reveal that the films exhibit self-defocusing thermal nonlinearity. The third-order nonlinear optical susceptibility χ(3) was found to be of the order of 10-3 esu and 10-2 esu for annealed MZO thin films at 200 °C and 400 °C respectively. The dependence of grain size on the observed nonlinearity was revealed by atomic force microscopy analysis. Optical limiting studies were carried out for a range of input power levels and an optical limiting of about ∼8 mW was observed indicating the possible application for photonic devices.

  9. Linear models for airborne-laser-scanning-based operational forest inventory with small field sample size and highly correlated LiDAR data

    USGS Publications Warehouse

    Junttila, Virpi; Kauranne, Tuomo; Finley, Andrew O.; Bradford, John B.

    2015-01-01

    Modern operational forest inventory often uses remotely sensed data that cover the whole inventory area to produce spatially explicit estimates of forest properties through statistical models. The data obtained by airborne light detection and ranging (LiDAR) correlate well with many forest inventory variables, such as the tree height, the timber volume, and the biomass. To construct an accurate model over thousands of hectares, LiDAR data must be supplemented with several hundred field sample measurements of forest inventory variables. This can be costly and time consuming. Different LiDAR-data-based and spatial-data-based sampling designs can reduce the number of field sample plots needed. However, problems arising from the features of the LiDAR data, such as a large number of predictors compared with the sample size (overfitting) or a strong correlation among predictors (multicollinearity), may decrease the accuracy and precision of the estimates and predictions. To overcome these problems, a Bayesian linear model with the singular value decomposition of predictors, combined with regularization, is proposed. The model performance in predicting different forest inventory variables is verified in ten inventory areas from two continents, where the number of field sample plots is reduced using different sampling designs. The results show that, with an appropriate field plot selection strategy and the proposed linear model, the total relative error of the predicted forest inventory variables is only 5%–15% larger using 50 field sample plots than the error of a linear model estimated with several hundred field sample plots when we sum up the error due to both the model noise variance and the model’s lack of fit.

  10. Thyroid scan

    MedlinePlus

    ... thyroid; Radioactive iodine uptake and scan test - thyroid; Nuclear scan - thyroid ... the test. Ask your provider or the radiology/nuclear medicine team performing the scan about taking precautions.

  11. Nuclear Scans

    MedlinePlus

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

  12. Increased risk of distal ventriculoperitoneal shunt obstruction associated with slit valves or distal slits in the peritoneal catheter.

    PubMed

    Cozzens, J W; Chandler, J P

    1997-11-01

    The authors describe a relationship between the presence of distal shunt catheter side-wall slits and distal catheter obstruction in a single-surgeon series of ventriculoperitoneal (VP) shunt revisions. Between 1985 and 1996, 168 operations for VP shunt revision were performed by the senior author (J.W.C.) in 71 patients. Indications for shunt revision included obstruction in 140 operations; overdrainage or underdrainage requiring a change of valve in 17 operations; inadequate length of distal shunt tubing resulting in the distal end no longer reaching the peritoneum in five operations; the ventricular catheter in the wrong ventricle or space, requiring repositioning in five operations; and a disconnected or broken shunt in one operation. Of the 140 instances of shunt obstruction, the blockage occurred at the ventricular end in 108 instances (77.1%), the peritoneal end in 17 (12.1%), the ventricular and the peritoneal end in 14 (10%), and in the valve mechanism (not including distal slit valves) in one (0.8%). Thus, the peritoneal end was obstructed in 31 (22.1%) of 140 cases of shunt malfunction. In every case in which the peritoneal end was obstructed, some form of distal slit was found: either a distal slit valve in an otherwise closed catheter or slits in the side of an open catheter. No instances were found of distal peritoneal catheter obstruction when the peritoneal catheter was a simple open-ended tube with no accompanying side slits (0 of 55). It is concluded that side slits in the distal peritoneal catheters of VP shunts are associated with a greater incidence of distal shunt obstruction.

  13. Air sampling of mold spores by slit impactors: yield comparison.

    PubMed

    Pityn, Peter J; Anderson, James

    2013-01-01

    The performance of simple slit impactors for air sampling of mold contamination was compared under field conditions. Samples were collected side-by-side, outdoors in quadruplicates with Burkhard (ambient sampler) and Allergenco MK3 spore traps and with two identical Allergenco slit cassettes operated at diverse flow rates of 5 and 15 L/min, respectively. The number and types of mold spores in each sample were quantified by microscopy. Results showed all four single-stage slit impactors produced similar spore yields. Moreover, paired slit cassettes produced similar outcomes despite a three-fold difference in their sampling rate. No measurable difference in the amount or mix of mold spores per m(3)of air was detected. The implications for assessment of human exposures and interpretation of indoor/outdoor fungal burden are discussed. These findings demonstrate that slit cassettes capture most small spores, effectively and without bias, when operated at a range of flow rates including the lower flow rates used for personal sampling. Our findings indicate sampling data for mold spores correlate for different single stage impactor collection methodologies and that data quality is not deteriorated by operating conditions deviating from manufacturers' norms allowing such sampling results to be used for scientific, legal, investigative, or property insurance purposes. The same conclusion may not be applied to other particle sampling instruments and mulit-stage impactors used for ambient particulate sampling, which represent an entirely different scenario. This knowledge may help facilitate comparison between scientific studies where methodological differences exist.

  14. Decoherence in a double-slit quantum eraser

    SciTech Connect

    Torres-Ruiz, F. A.; Lima, G.; Delgado, A.; Saavedra, C.; Padua, S.

    2010-04-15

    We study and experimentally implement a double-slit quantum eraser in the presence of a controlled decoherence mechanism. A two-photon state, produced in a spontaneous parametric down-conversion process, is prepared in a maximally entangled polarization state. A birefringent double slit is illuminated by one of the down-converted photons, and it acts as a single-photon two-qubits controlled-not gate that couples the polarization with the transversal momentum of these photons. The other photon, which acts as a which-path marker, is sent through a Mach-Zehnder-like interferometer. When the interferometer is partially unbalanced, it behaves as a controlled source of decoherence for polarization states of down-converted photons. We show the transition from wavelike to particle-like behavior of the signal photons crossing the double slit as a function of the decoherence parameter, which depends on the length path difference at the interferometer.

  15. Evaluation of Slit Sampler in Quantitative Studies of Bacterial Aerosols

    PubMed Central

    Ehrlich, Richard; Miller, Sol; Idoine, L. S.

    1966-01-01

    Quantitative studies were conducted to evaluate the efficiency of the slit sampler in collecting airborne Serratia marcescens and Bacillus subtilis var. niger, and to compare it with the collecting efficiency of the all-glass impinger AGI-30. The slit sampler was approximately 50% less efficient than the AGI-30. This ratio remained the same whether liquid or dry cultures were disseminated when the sample was taken at 2 min of aerosol cloud life. At 30 min of aerosol cloud life, this ratio was approximately 30% for B. subtilis var. niger. S. marcescens recoveries by the slit sampler were, however, only 17% lower than the AGI-30 at 30 min of cloud age, indicating a possible interaction involving the more labile vegetative cells, aerosol age, and method of collection. PMID:4961550

  16. Sensitizing the Slit Diaphragm with TRPC6 ion channels.

    PubMed

    Möller, Clemens C; Flesche, Jan; Reiser, Jochen

    2009-05-01

    Physiologic permeability of the glomerular capillary depends on the normal structure of podocyte foot processes forming a functioning slit diaphragm in between. Mutations in several podocyte genes as well as specific molecular pathways have been identified as the cause for progressive kidney failure with urinary protein loss. Podocyte injury is a hallmark of glomerular disease, which is generally displayed by the rearrangement of the podocyte slit diaphragm and the actin cytoskeleton. Recent studies demonstrate a unique role for the Ca(2+)-permeable ion channel protein TRPC6 as a regulator of glomerular ultrafiltration. In both genetic and acquired forms of proteinuric kidney disease, dysregulation of podocyte TRPC6 plays a pathogenic role. This article illustrates how recent findings add to emerging concepts in podocyte biology, particularly mechanosensation and signaling at the slit diaphragm.

  17. Double-slit interference of radially polarized vortex beams

    NASA Astrophysics Data System (ADS)

    Qi, Junli; Wang, Weihua; Li, Xiujian; Wang, Xiaofeng; Sun, Wenchao; Liao, Jiali; Nie, Yongming

    2014-04-01

    Both radially polarized (RP) and radially polarized vortex (RPV) beams are generated by an experimental setup with one phase-only liquid crystal spatial light modulator which efficiently modulates the phase retardation distributions of input beam by twice reflections. The polarizing properties and double-slit interference of both RP and RPV beams are investigated in detail. Misplacement and tilt appear in double-slit interference fringes of both RP beams and RPV beams in simulations and experiments. The fringe tilt number F in the intermediate region is proportional to the topological charge l of RPV beams with the approximate relation Fs(l)=0.8125l in simulations and Fe(l)=0.8182l in experiments. The double-slit interference method can be utilized to determine and analyze the topological charge of the beams.

  18. The differential roles of Slit2-exon 15 splicing variants in angiogenesis and HUVEC permeability.

    PubMed

    Yang, Yun-Chiu; Chen, Pei-Ni; Wang, Siou-Yu; Liao, Chen-Yi; Lin, Yu-Ying; Sun, Shih-Rhong; Chiu, Chun-Ling; Hsieh, Yih-Shou; Shieh, Jia-Ching; Chang, Jinghua Tsai

    2015-07-01

    Slit2, a secreted glycoprotein, is down-regulated in many cancers. Slit2/Robo signaling pathway plays an important, but controversial, role in angiogenesis. We identified splicing variants of Slit2 at exon 15, Slit2-WT and Slit2-ΔE15, with differential effects on proliferation and invasive capability of lung cancer cells. The aim of this study was to elucidate the differential roles of these exon 15 splicing variants in angiogenesis. Our results revealed that both Slit2-WT and Slit2-ΔE15 inhibit motility of human umbilical vein endothelial cells (HUVECs). The conditioned medium (CM) collected from CL1-5/VC or CL1-5/Slit2-WT lung adenocarcinoma cells blocked HUVEC tube formation and angiogenesis on chorioallantoic membrane (CAM) assay when compared with untreated HUVECs and CAM, respectively. However, CM of CL1-5/Slit2-ΔE15 restored the quality of tubes and the size of vessels. Although both Slit2-WT and Slit2-ΔE15 inhibited permeability induced by CM of cancer cells, Slit2-ΔE15 exhibited stronger effect. These results suggested that Slit2-ΔE15 plays important roles in normalization of blood vessels by enhancing tube quality and tightening endothelial cells, while Slit2-WT only enhances tightening of endothelial cells. It appears that Robo4 is responsible for Slit2 isoform-mediated inhibition of permeability, while neither Robo1 nor Robo4 is required for Slit2-ΔE15-enhanced tube quality. The results of this study suggest that Slit2-ΔE15 splicing form is a promising molecule for normalizing blood vessels around a tumor, which, in turn, may increase efficacy of chemotherapy and radiotherapy.

  19. SPECIAL ANALYSIS OF OPERATIONAL STORMWATER RUNOFF COVERS OVER SLIT TRENCHES

    SciTech Connect

    Collard, L; Luther Hamm, L

    2008-12-18

    Solid Waste Management (SWM) commissioned this Special Analysis (SA) to determine the effects of placing operational stormwater runoff covers (referred to as covers in the remainder of this document) over slit trench (ST) disposal units ST1 through ST7 (the center set of slit trenches). Previously the United States Department of Energy (DOE) entered into an agreement with the United States Environmental Protection Agency (EPA) and the South Carolina Department of Health and Environmental Control (SCDHEC) to place covers over Slit Trenches 1 and 2 to be able to continue disposing Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) solid waste (see USDOE 2008). Because the covers changed the operating conditions, DOE Order 435.1 (DOE 1999) required that an SA be performed to assess the impact. This Special Analysis has been prepared to determine the effects of placing covers over slit trenches at about years 5, 10 and 15 of the 30-year operational period. Because some slit trenches have already been operational for about 15 years, results from analyzing covers at 5 years and 10 years provide trend analysis information only. This SA also examined alternatives of covering Slit Trenches 1 and 2 with one cover and Slit Trenches 3 and 4 with a second cover versus covering them all with a single cover. Based on modeling results, minimal differences exist between covering Slit Trench groups 1-2 and 3-4 with two covers or one large cover. This SA demonstrates that placement of covers over slit trenches will slow the subsequent release and transport of radionuclides in the vadose zone in the early time periods (from time of placement until about 100 years). Release and transport of some radionuclides in the vadose zone beyond 100 years were somewhat higher than for the case without covers. The sums-of-fractions (SOFs) were examined for the current waste inventory in ST1 and ST2 and for estimated inventories at closure for ST3 through ST7. In all

  20. Robust scatter correction method for cone-beam CT using an interlacing-slit plate

    NASA Astrophysics Data System (ADS)

    Huang, Kui-Dong; Xu, Zhe; Zhang, Ding-Hua; Zhang, Hua; Shi, Wen-Long

    2016-06-01

    Cone-beam computed tomography (CBCT) has been widely used in medical imaging and industrial nondestructive testing, but the presence of scattered radiation will cause significant reduction of image quality. In this article, a robust scatter correction method for CBCT using an interlacing-slit plate (ISP) is carried out for convenient practice. Firstly, a Gaussian filtering method is proposed to compensate the missing data of the inner scatter image, and simultaneously avoid too-large values of calculated inner scatter and smooth the inner scatter field. Secondly, an interlacing-slit scan without detector gain correction is carried out to enhance the practicality and convenience of the scatter correction method. Finally, a denoising step for scatter-corrected projection images is added in the process flow to control the noise amplification The experimental results show that the improved method can not only make the scatter correction more robust and convenient, but also achieve a good quality of scatter-corrected slice images. Supported by National Science and Technology Major Project of the Ministry of Industry and Information Technology of China (2012ZX04007021), Aeronautical Science Fund of China (2014ZE53059), and Fundamental Research Funds for Central Universities of China (3102014KYJD022)

  1. Gallium scan

    MedlinePlus

    Liver gallium scan; Bony gallium scan ... You will get a radioactive material called gallium injected into your vein. The gallium travels through the bloodstream and collects in the bones and certain organs. Your health care provider will ...

  2. The nephridial hypothesis of the gill slit origin.

    PubMed

    Ezhova, Olga V; Malakhov, Vladimir V

    2015-12-01

    Metameric gill slits are mysterious structures, unique for Chordata and Hemichordata, and also, perhaps, for the extinct Cambrian Calcichordata. There is a discussed hypothesis of the gill slits origin from the metameric nephridia. According to the hypothesis, the hypothetical metameric deuterostome ancestor had in each segment a pair of coelomoducts and a pair of intestinal pockets. In the anterior segments, the coelomoducts have fused with the intestinal pockets. As a result, each nephridium opened both into the gut and into the environment. Then the dissepiments and funnels reduced in all segments except the collar one. Thus, in recent enteropneusts, only the first pair of gill slits keeps the ancestral arrangement communicating at the same time with the gut, with the environment, and with the coelom of the preceding (collar) segment. In the anterior part of the branchio-genital trunk region of enteropneusts, the metameric intestinal pockets remained, as well as the metameric coelomoducts functioning as the ducts of the metameric gonads, i.e., as the gonoducts. The consequence of the hypothesis is that the metameric gill pores originate from the metameric excreting pores, and the metameric branchial sacs originate from the metameric endodermal pockets of the gut fused with the coelomoducts. The metameric gill slits by themselves correspond with metameric openings connecting the gut with metameric intestinal pockets. J. Exp. Zool. (Mol. Dev. Evol.) 324B: 647-652, 2015. © 2015 Wiley Periodicals, Inc. PMID:26227807

  3. A Spreadsheet Simulation for a Young's Double Slits Experiment.

    ERIC Educational Resources Information Center

    Field, Richard

    1995-01-01

    Describes a spreadsheet that can be used to show the changes in intensity of Fraunhofer diffraction patterns produced by a single and double slits arrangement. Discusses a practical demonstration of diffraction that allows data to be logged and entered into the spreadsheet. (DDR)

  4. Slit diaphragm junctional complex and regulation of the cytoskeleton.

    PubMed

    Garg, Puneet; Verma, Rakesh; Holzman, Lawrence B

    2007-01-01

    In recent years, identification of proteins found at the slit diaphragm has greatly improved our understanding of the molecular mechanisms responsible for forming and maintaining the glomerular filtration barrier. This review examines the function of proteins identified at the podocyte intercellular junction in coordinating podocyte intercellular junction dynamics or cytoskeletal dynamics.

  5. The nephridial hypothesis of the gill slit origin.

    PubMed

    Ezhova, Olga V; Malakhov, Vladimir V

    2015-12-01

    Metameric gill slits are mysterious structures, unique for Chordata and Hemichordata, and also, perhaps, for the extinct Cambrian Calcichordata. There is a discussed hypothesis of the gill slits origin from the metameric nephridia. According to the hypothesis, the hypothetical metameric deuterostome ancestor had in each segment a pair of coelomoducts and a pair of intestinal pockets. In the anterior segments, the coelomoducts have fused with the intestinal pockets. As a result, each nephridium opened both into the gut and into the environment. Then the dissepiments and funnels reduced in all segments except the collar one. Thus, in recent enteropneusts, only the first pair of gill slits keeps the ancestral arrangement communicating at the same time with the gut, with the environment, and with the coelom of the preceding (collar) segment. In the anterior part of the branchio-genital trunk region of enteropneusts, the metameric intestinal pockets remained, as well as the metameric coelomoducts functioning as the ducts of the metameric gonads, i.e., as the gonoducts. The consequence of the hypothesis is that the metameric gill pores originate from the metameric excreting pores, and the metameric branchial sacs originate from the metameric endodermal pockets of the gut fused with the coelomoducts. The metameric gill slits by themselves correspond with metameric openings connecting the gut with metameric intestinal pockets. J. Exp. Zool. (Mol. Dev. Evol.) 324B: 647-652, 2015. © 2015 Wiley Periodicals, Inc.

  6. A Variant of Young's Double Slit Experiment for Educational Purposes

    ERIC Educational Resources Information Center

    Henault, Francois; Spang, Alain

    2011-01-01

    We describe a variant of the classical Young's double slit experiment that can be easily realized in any classroom, in order to evidence the wave nature of light. The proposed apparatus and its simplified theory are described and pictures of fringes, readily obtained using only cheap and off-the-shelf optical components, are reproduced. The…

  7. H sup minus temperature measurements by a slit diagnostic technique

    SciTech Connect

    Sherman, J.D.; Smith, H.V. Jr.; Geisik, C.; Allison, P.

    1991-01-01

    H{sup {minus}} ion beams are extracted at 5-25 kV from a long, narrow slit on a Penning surface-plasma source (the 8X source). The extraction geometry produces negligible transverse electric fields (focusing effects) along the slit length. Therefore, the ion angular spread reflects the distribution of ion energies at the plasma surface. The angular distributions are measured with an electric-sweep emittance scanner whose slits are oriented normal to the long dimension of the emission slit. The nearly-Maxwellian angular distributions measured over the central portions of the ribbon beam give kT{sub H{sup {minus}}} of 0.1 to 0.2 eV for a 2-A dc discharge and 0.8 to 1.0 eV for 350- to 500-A pulsed discharges. This diagnostic technique has sufficient position resolution to allow measurement of the kT{sub H{sup {minus}}} spatial distributions. It also allows study of the kT{sub H{sup {minus}}} dependencies on ion source parameters (e.g., increasing the H{sub 2} gas flow lowers kT{sub H{sup {minus}}}). 7 refs., 7 figs.

  8. A Portable Double-Slit Quantum Eraser with Individual Photons

    ERIC Educational Resources Information Center

    Dimitrova, T. L.; Weis, A.

    2011-01-01

    The double-slit experiment has played an important role in physics, from supporting the wave theory of light, via the discussions of the wave-particle duality of light (and matter) to the foundations of modern quantum optics. Today it keeps playing an active role in the context of quantum optics experiments involving single photons. In this paper,…

  9. Bone scanning.

    PubMed

    Greenfield, L D; Bennett, L R

    1975-03-01

    Scanning is based on the uptake of a nuclide by the crystal lattice of bone and is related to bone blood flow. Cancer cells do not take up the tracer. Normally, the scan visualizes the highly vascular bones. Scans are useful and are indicated in metastatic bone disease, primary bone tumors, hematologic malignancies and some non-neoplastic diseases. The scan is more sensitive than x-ray in the detection of malignant diseases of the skeleton. PMID:1054210

  10. Axon guidance factor SLIT2 inhibits neural invasion and metastasis in pancreatic cancer.

    PubMed

    Göhrig, Andreas; Detjen, Katharina M; Hilfenhaus, Georg; Körner, Jan L; Welzel, Martina; Arsenic, Ruza; Schmuck, Rosa; Bahra, Marcus; Wu, Jane Y; Wiedenmann, Bertram; Fischer, Christian

    2014-03-01

    Pancreatic ductal adenocarcinoma (PDAC) metastasizes by neural, vascular, and local invasion routes, which limit patient survival. In nerves and vessels, SLIT2 and its ROBO receptors constitute repellent guidance cues that also direct epithelial branching. Thus, the SLIT2-ROBO system may represent a key pinch point to regulate PDAC spread. In this study, we examined the hypothesis that escaping from repellent SLIT2-ROBO signaling is essential to enable PDAC cells to appropriate their local stromal infrastructure for dissemination. Through immunohistochemical analysis, we detected SLIT2 receptors ROBO1 and ROBO4 on epithelia, nerves, and vessels in healthy pancreas and PDAC specimens, respectively. SLIT2 mRNA expression was reduced in PDAC compared with nontransformed pancreatic tissues and cell lines, suggesting a reduction in SLIT2-ROBO pathway activity in PDAC. In support of this interpretation, restoring the SLIT2 expression in SLIT2-deficient PDAC cells inhibited their bidirectional chemoattraction with neural cells, and more specifically, impaired unidirectional PDAC cell navigation along outgrowing neurites in models of neural invasion. Restoring autocrine/paracrine SLIT2 signaling was also sufficient to inhibit the directed motility of PDAC cells, but not their random movement. Conversely, RNA interference-mediated silencing of ROBO1 stimulated the motility of SLIT2-competent PDAC cells. Furthermore, culture supernatants from SLIT2-competent PDAC cells impaired migration of endothelial cells (human umbilical vein endothelial cells), whereas an N-terminal SLIT2 cleavage fragment stimulated such migration. In vivo investigations of pancreatic tumors with restored SLIT2 expression demonstrated reduced invasion, metastasis, and vascularization, with opposing effects produced by ROBO1 silencing in tumor cells or sequestration of endogenous SLIT2. Analysis of clinical specimens of PDAC showed that those with low SLIT2 mRNA expression exhibited a higher incidence

  11. Role of intensity fluctuations in third-order correlation double-slit interference of thermal light.

    PubMed

    Chen, Xi-Hao; Chen, Wen; Meng, Shao-Ying; Wu, Wei; Wu, Ling-An; Zhai, Guang-Jie

    2013-07-01

    A third-order double-slit interference experiment with a pseudothermal light source in the high-intensity limit has been performed by actually recording the intensities in three optical paths. It is shown that not only can the visibility be dramatically enhanced compared to the second-order case as previously theoretically predicted and shown experimentally, but also that the higher visibility is a consequence of the contribution of third-order correlation interaction terms, which is equal to the sum of all contributions from second-order correlation. It is interesting that, when the two reference detectors are scanned in opposite directions, negative values for the third-order correlation term of the intensity fluctuations may appear. The phenomenon can be completely explained by the theory of classical statistical optics and is the first concrete demonstration of the influence of the third-order correlation terms.

  12. Cross slit-grooves grid structure for surface plasmon resonant sensor

    NASA Astrophysics Data System (ADS)

    Lee, Jooho; Nakarmi, Bikash; Kim, Bongho; Jang, Wonjae; Bang, Yousung; Lee, Muyoung; Won, Y. H.

    2016-03-01

    Surface plasmon resonant (SPR) phenomenon is widely researched for various purposes, among which biomedical sensing is getting more attentions as they are suitable for surface functionalization acting as a bio recognition element to detect different biological infections. The common method of surface resonant is propagating SPR such as reflection method. Another method which is widely used for SPR is localized SPR which use nanostructures in thin metal. Various structures such as slit only, slit- groove and slit-multiple groove are used for generation of SPR and obtaining the optimum optical transmittance through the structure. The number and position of slits and grooves affect transmittance through the structure. In this paper we propose a new structure of cross slit-grooves structure, which includes slit-groove structure in grid form. The slit-grooves structures are arranged in such a way that it forms symmetrical structure in two dimension with slit and groove and hence the transmittance with cross slit-grooves structure increases significantly. The cross slit-grooves structure takes the advantage of symmetrical slit and groove by using both dimensional structures for generating SPR which increases the transmittance through the structure. A comparison of proposed slit-grooves grid structure with straight slit-grooves structure is carried out to show the increase in transmittance through the cross slit-grooves grid structure. Plane wavelength of 400 nm to 900 nm is used for the analysis of transmittance through the Ag slit-grooves grid structures with glass substrate. We also measure the change in transmittance with change in refractive index, which can be helpful for measuring different chemical analytes, and hence can be used for different chemical and biosensors applications.

  13. Degree of polarization in Young's double-slit interference experiment formed by stochastic electromagnetic beams.

    PubMed

    Chen, Ziyang; Pu, Jixiong

    2007-07-01

    We analyze the behavior of the degree of polarization in the interference field of Young's double-slit experiment. We analyze the degree of polarization in Young's double-slit interference experiment illuminated by stochastic electromagnetic beams. The distribution of the degree of polarization in the interference field for different correlation lengths and different slit widths is investigated. Furthermore, it is shown that the degree of polarization for a fixed observation point may take on values different from those it takes in the slits, depending not only on the value of the correlation length but also on the width of the slit.

  14. Slit2 is decreased after spontaneous labour in myometrium and regulates pro-labour mediators.

    PubMed

    Lim, Ratana; Liong, Stella; Barker, Gillian; Lappas, Martha

    2014-12-01

    Preterm birth, a global healthcare problem, is commonly associated with inflammation. As Slit2 plays an emerging role in inflammation, the purpose of this study was to determine the effect of Slit2 on labour mediators in human gestational tissues. Slit2 mRNA and protein expression were assessed using qRT-PCR and immunohistochemistry in foetal membranes and myometrium obtained before and after labour. Slit2 silencing was achieved using siRNA in primary myometrial cells. Pro-inflammatory and pro-labour mediators were evaluated by qRT-PCR, ELISA and gelatin zymography. Slit2 mRNA and protein expression were found to be significantly lower in myometrium after labour onset. There was no effect of term or preterm labour on Slit2 expression in foetal membranes. Slit2 mRNA expression was decreased in myometrium treated with LPS and IL-1β. Slit2 siRNA in myometrial cells increased IL-1β-induced pro-inflammatory cytokine gene expression and release (IL-6 and IL-8), COX-2 expression and prostaglandin PGE2 and PGF2α release, and MMP-9 gene expression and pro MMP-9 release. There was no effect of Slit2 siRNA on IL-1β-induced NF-κB transcriptional activity. Our results demonstrate that Slit2 is decreased in human myometrium after labour and our knock-down studies describe an anti-inflammatory effect of Slit2 in myometrial cells.

  15. Signaling Mechanisms Underlying Slit2-Induced Collapse of Xenopus Retinal Growth Cones

    PubMed Central

    Piper, Michael; Anderson, Richard; Dwivedy, Asha; Weinl, Christine; van Horck, Francis; Leung, Kin Mei; Cogill, Emily; Holt, Christine

    2013-01-01

    Summary Slits mediate multiple axon guidance decisions, but the mechanisms underlying the responses of growth cones to these cues remain poorly defined. We show here that collapse induced by Slit2-conditioned medium (Slit2-CM) in Xenopus retinal growth cones requires local protein synthesis (PS) and endocytosis. Slit2-CM elicits rapid activation of translation regulators and MAP kinases in growth cones, and inhibition of MAPKs or disruption of heparan sulfate blocks Slit2-CM-induced PS and repulsion. Interestingly, Slit2-CM causes a fast PS-dependent decrease in cytoskeletal F-actin concomitant with a PS-dependent increase in the actin-depolymerizing protein cofilin. Our findings reveal an unexpected link between Slit2 and cofilin in growth cones and suggest that local translation of actin regulatory proteins contributes to repulsion. PMID:16423696

  16. Virtual cathode microwave generator having annular anode slit

    DOEpatents

    Kwan, Thomas J. T.; Snell, Charles M.

    1988-01-01

    A microwave generator is provided for generating microwaves substantially from virtual cathode oscillation. Electrons are emitted from a cathode and accelerated to an anode which is spaced apart from the cathode. The anode has an annular slit therethrough effective to form the virtual cathode. The anode is at least one range thickness relative to electrons reflecting from the virtual cathode. A magnet is provided to produce an optimum magnetic field having the field strength effective to form an annular beam from the emitted electrons in substantial alignment with the annular anode slit. The magnetic field, however, does permit the reflected electrons to axially diverge from the annular beam. The reflected electrons are absorbed by the anode in returning to the real cathode, such that substantially no reflexing electrons occur. The resulting microwaves are produced with a single dominant mode and are substantially monochromatic relative to conventional virtual cathode microwave generators.

  17. Video recording true single-photon double-slit interference

    NASA Astrophysics Data System (ADS)

    Aspden, Reuben S.; Padgett, Miles J.; Spalding, Gabriel C.

    2016-09-01

    Commercially available cameras do not have a low-enough dark noise to directly capture double-slit interference at the single photon level. In this work, camera noise levels are significantly reduced by activating the camera only when the presence of a photon has been detected by the independent detection of a time-correlated photon produced via parametric down-conversion. This triggering scheme provides the improvement required for direct video imaging of Young's double-slit experiment with single photons, allowing clarified versions of this foundational demonstration. We present video data of the evolving interference patterns. Also, we introduce variations on this experiment aimed at promoting discussion of the role spatial coherence plays in such a measurement, emphasizing complementary aspects of single-photon measurement and highlighting the roles of transverse position and momentum correlations between down-converted photons, including examples of "ghost" imaging and diffraction.

  18. Adaptive slit beam shaping for direct laser written waveguides.

    PubMed

    Salter, P S; Jesacher, A; Spring, J B; Metcalf, B J; Thomas-Peter, N; Simmonds, R D; Langford, N K; Walmsley, I A; Booth, M J

    2012-02-15

    We demonstrate an improved method for fabricating optical waveguides in bulk materials by means of femtosecond laser writing. We use an LC spatial light modulator (SLM) to shape the beam focus by generating adaptive slit illumination in the pupil of the objective lens. A diffraction grating is applied in a strip across the SLM to simulate a slit, with the first diffracted order mapped onto the pupil plane of the objective lens while the zeroth order is blocked. This technique enables real-time control of the beam-shaping parameters during writing, facilitating the fabrication of more complicated structures than is possible using nonadaptive methods. Waveguides are demonstrated in fused silica with a coupling loss to single-mode fibers in the range of 0.2 to 0.5 dB and propagation loss <0.4 dB/cm.

  19. Double-Slit Interference Pattern for a Macroscopic Quantum System

    NASA Astrophysics Data System (ADS)

    Naeij, Hamid Reza; Shafiee, Afshin

    2016-07-01

    In this study, we solve analytically the Schrödinger equation for a macroscopic quantum oscillator as a central system coupled to two environmental micro-oscillating particles. Then, the double-slit interference patterns are investigated in two limiting cases, considering the limits of uncertainty in the position probability distribution. Moreover, we analyze the interference patterns based on a recent proposal called stochastic electrodynamics with spin. Our results show that when the quantum character of the macro-system is decreased, the diffraction pattern becomes more similar to a classical one. We also show that, depending on the size of the slits, the predictions of quantum approach could be apparently different with those of the aforementioned stochastic description.

  20. Virtual cathode microwave generator having annular anode slit

    SciTech Connect

    Kwan, T.J.T.; Snell, C.M.

    1988-03-08

    A microwave generator using an oscillating virtual cathode is described comprising: a cathode for emitting electrons; an anode for accelerating emitted electrons from the cathode, the anode having an annular slit therethrough effective for forming the virtual cathode and having at least one range thickness relative to electrons reflected from the virtual cathode; and magnet means for producing a magnetic field having a field strength effective to form an annular beam from the emitted electrons in substantial alignment with the annular anode slit and to enable the electrons reflected from the virtual cathode to axially diverge from the annular beam. The reflected electrons return toward the cathode diverge from the annular beam and are absorbed by the anode to substantially eliminate electrons reflexing between the cathode and the virtual cathode.

  1. Long-Slit Spectra of Mars in the Thermal Infrared

    NASA Technical Reports Server (NTRS)

    Rowland, C. M.; Sloan, G. C.; Roush, T.; Witteborn, Fred C. (Technical Monitor)

    1994-01-01

    We have obtained long-slit spectra of Mars in the 7-14 micrometer regime. Our two integrations, taken 1993 March 2, are spaced about 2 hours apart and are centered at longitudes of roughly 210 and 240 degrees. The data cover the Elysium Planitia and volcanic regions, the classical dark albedo regions of Cerburus and central and eastern Hesperia, and the classical bright albedo region Utopia Planitia. We have deconvolved the point spread function from the images using a maximum entropy reconstruction algorithm; the resulting spatial resolution of the images is better than 1". Mars occupies approximately 9" of the slit, and we have detected variations in the spectral emission from different areas of the planet. We are in the process of interpreting these spectral variations in terms of the temperature and composition of the surface and the transmission of the Martian atmospheric dust and gases.

  2. Line-scanning, stage scanning confocal microscope

    NASA Astrophysics Data System (ADS)

    Carucci, John A.; Stevenson, Mary; Gareau, Daniel

    2016-03-01

    We created a line-scanning, stage scanning confocal microscope as part of a new procedure: video assisted micrographic surgery (VAMS). The need for rapid pathological assessment of the tissue on the surface of skin excisions very large since there are 3.5 million new skin cancers diagnosed annually in the United States. The new design presented here is a confocal microscope without any scanning optics. Instead, a line is focused in space and the sample, which is flattened, is physically translated such that the line scans across its face in a direction perpendicular to the line its self. The line is 6mm long and the stage is capable of scanning 50 mm, hence the field of view is quite large. The theoretical diffraction-limited resolution is 0.7um lateral and 3.7um axial. However, in this preliminary report, we present initial results that are a factor of 5-7 poorer in resolution. The results are encouraging because they demonstrate that the linear array detector measures sufficient signal from fluorescently labeled tissue and also demonstrate the large field of view achievable with VAMS.

  3. Asymmetric Fraunhofer diffraction from roller-blade slits.

    PubMed

    Libbert, J L; Pitney, J A; Robinson, I K

    1997-05-01

    X-ray diffraction experiments under coherent conditions have been made possible by the development of new sources of synchrotron radiation, but make tough demands on the experimental apparatus. Here we describe the design and initial testing of a precision aperture that uses polished molybdenum rods as the slit blades. The device has an inherent asymmetry which is accurately accounted for by a simple modification to the Fraunhofer diffraction function.

  4. Grazing incidence off Rowland spectrometer with shifted slit.

    PubMed

    Antsiferov, P S; Dorokhin, L A; Krainov, P V

    2016-05-01

    The article presents the analysis of the scheme of grazing incidence spectrometer with the normal to the line of site registration of the spectrum. The scheme is intended for the usage of the micro channel plate assembly as a spectrum detector. The main feature is the displacement of the entrance slit from the Rowland circle. The results of the experimental test of the spectral resolution (λ/δλ around 200) are presented and compared with the theoretical estimations. PMID:27250391

  5. Low pressure drop, multi-slit virtual impactor

    DOEpatents

    Bergman, Werner

    2002-01-01

    Fluid flow is directed into a multiplicity of slit nozzles positioned so that the fluid flow is directed into a gap between the nozzles and (a) a number of receiving chambers and (b) a number of exhaust chambers. The nozzles and chambers are select so that the fluid flow will be separated into a first particle flow component with larger and a second particle flow component with the smaller particles.

  6. Young's double-slit interference pattern from a twisted beam

    NASA Astrophysics Data System (ADS)

    Emile, Olivier; Emile, Janine

    2014-10-01

    A wide range of diffractive elements have been used to evaluate the topological charge of Laguerre-Gaussian beams. Here, we show theoretically and experimentally that this charge can be simply and readily measured from the interference pattern in Young's double-slit experiment. It can be evaluated from the twisting order of the interference. The results are confronted with previously published studies. The potentialities of the method are then compared with existing techniques.

  7. Rapid Prototyping of Nanofluidic Slits in a Silicone Bilayer

    PubMed Central

    Kole, Thomas P.; Liao, Kuo-Tang; Schiffels, Daniel; Ilic, B. Robert; Strychalski, Elizabeth A.; Kralj, Jason G.; Liddle, J. Alexander; Dritschilo, Anatoly; Stavis, Samuel M.

    2015-01-01

    This article reports a process for rapidly prototyping nanofluidic devices, particularly those comprising slits with microscale widths and nanoscale depths, in silicone. This process consists of designing a nanofluidic device, fabricating a photomask, fabricating a device mold in epoxy photoresist, molding a device in silicone, cutting and punching a molded silicone device, bonding a silicone device to a glass substrate, and filling the device with aqueous solution. By using a bilayer of hard and soft silicone, we have formed and filled nanofluidic slits with depths of less than 400 nm and aspect ratios of width to depth exceeding 250 without collapse of the slits. An important attribute of this article is that the description of this rapid prototyping process is very comprehensive, presenting context and details which are highly relevant to the rational implementation and reliable repetition of the process. Moreover, this process makes use of equipment commonly found in nanofabrication facilities and research laboratories, facilitating the broad adaptation and application of the process. Therefore, while this article specifically informs users of the Center for Nanoscale Science and Technology (CNST) at the National Institute of Standards and Technology (NIST), we anticipate that this information will be generally useful for the nanofabrication and nanofluidics research communities at large, and particularly useful for neophyte nanofabricators and nanofluidicists. PMID:26958449

  8. Experimental demonstration of a quantum shutter closing two slits simultaneously

    NASA Astrophysics Data System (ADS)

    Okamoto, Ryo; Takeuchi, Shigeki

    2016-10-01

    The interference between two paths of a single photon at a double slit is widely considered to be the most paradoxical result of quantum theory. Here is a new interesting question to the phenomenon: can a single shutter simultaneously close two slits by effectively being in a superposition of different locations? Aharonov and Vaidman have shown that it is indeed possible to construct a quantum shutter that can close two slits and reflect a probe photon perfectly when its initial and final states are appropriately selected. Here we report the experimental demonstration of their proposal overcoming the difficulty to realize a ‘quantum shutter’ by employing photonic quantum routers. The reflectance ratio of 0.61 ± 0.027 surpasses the classical limit with 4.1 standard deviation, shedding new light on the unusual physical properties of quantum operations. This experimental demonstration, where the strong measurement and non-local superposition seem co-existing, provides an alternative to weak measurements as a way to explore the nature of quantum physics.

  9. Experimental demonstration of a quantum shutter closing two slits simultaneously

    PubMed Central

    Okamoto, Ryo; Takeuchi, Shigeki

    2016-01-01

    The interference between two paths of a single photon at a double slit is widely considered to be the most paradoxical result of quantum theory. Here is a new interesting question to the phenomenon: can a single shutter simultaneously close two slits by effectively being in a superposition of different locations? Aharonov and Vaidman have shown that it is indeed possible to construct a quantum shutter that can close two slits and reflect a probe photon perfectly when its initial and final states are appropriately selected. Here we report the experimental demonstration of their proposal overcoming the difficulty to realize a ‘quantum shutter’ by employing photonic quantum routers. The reflectance ratio of 0.61 ± 0.027 surpasses the classical limit with 4.1 standard deviation, shedding new light on the unusual physical properties of quantum operations. This experimental demonstration, where the strong measurement and non-local superposition seem co-existing, provides an alternative to weak measurements as a way to explore the nature of quantum physics. PMID:27739465

  10. Smart slit assembly for high-resolution spectrometers in space

    NASA Astrophysics Data System (ADS)

    Guldimann, Benedikt; Minoglou, Kyriaki

    2016-03-01

    This paper introduces a novel imaging spectrometer subsystem concept, the Smart Slit Assembly (SSA), that improves instrument performances and enables new features for future Earth Observation. Derived from CarbonSat (ESA study) requirements, a concept of an SSA based on MEMS micro-shutters/mirrors and associated instrument design aspects are presented. The SSA replaces the classical grating spectrometer slit aperture in the focal plane of the telescope with three core elements, namely an input multimode waveguide array followed by a spatial light modulator (SLM) and an output multimode waveguide array which ends at the slit aperture viewed by the spectrometer. The SLM's in-and-outputs being coupled to waveguide arrays leads to an enhanced SLM with light de-coherence, polarization scrambling and scene/object homogenization capabilities. The additional advantage of this subsystem's arrangement is that waveguide level homogeneous spatial light modulation can be achieved with spatially in-homogeneous coupling from in to output multimode waveguides, allowing new, simpler and less costly designs for the SLM part of the SSA. The SSA is particularly useful for instance to reduce stray light by scene/object selection or modulation (e.g. de-clouding, intensity equalization), relax on the required dynamic range of the detectors, increase spectral stability by waveguide level intensity homogenization/scrambling, continuous in-flight monitoring of the co-registration between two or several spectrometer channels and inflight monitoring of stray light.

  11. Improving FAIMS sensitivity using a planar geometry with slit interfaces.

    PubMed

    Mabrouki, Ridha; Kelly, Ryan T; Prior, David C; Shvartsburg, Alexandre A; Tang, Keqi; Smith, Richard D

    2009-09-01

    Differential mobility spectrometry or field asymmetric waveform ion mobility spectrometry (FAIMS) is gaining broad acceptance for analyses of gas-phase ions, especially in conjunction with largely orthogonal separation methods such as mass spectrometry (MS) and/or conventional (drift tube) ion mobility spectrometry. In FAIMS, ions are filtered while passing through a gap between two electrodes that may have planar or curved (in particular, cylindrical) geometry. Despite substantial inherent advantages of the planar configuration and its near-universal adoption in current stand-alone FAIMS devices, commercial FAIMS/MS systems have employed curved FAIMS geometries that can be more effectively interfaced to MS. Here we report a new planar (p-) FAIMS design with slit-shaped entrance and exit apertures that substantially increase ion transmission in and out of the analyzer. The entrance slit interface effectively couples p-FAIMS to multi-emitter electrospray ionization (ESI) sources, improving greatly the ion current introduced to the device and allowing liquid flow rates up to approximately 50 microL/min. The exit slit interface increases the transmission of ribbon-shaped ion beams output by the p-FAIMS to downstream stages such as a MS. Overall, the ion signal in ESI/FAIMS/MS analyses increases by over an order of magnitude without affecting FAIMS resolution.

  12. Improving FAIMS Sensitivity using a Planar Geometry with Slit Interfaces

    SciTech Connect

    Mabrouki, Ridha B.; Kelly, Ryan T.; Prior, David C.; Shvartsburg, Alexandre A.; Tang, Keqi; Smith, Richard D.

    2009-09-01

    Differential mobility spectrometry or field asymmetric waveform ion mobility spectrometry (FAIMS) is gaining broad acceptance for analyses of gas-phase ions, especially in conjunction with largely orthogonal separation methods such as mass spectrometry (MS) and/or conventional (drift tube) ion mobility spectrometry. In FAIMS, ions are filtered while passing through a gap between two electrodes that may have planar or curved (in particular, cylindrical) geometry. Despite substantial inherent advantages of the planar configuration and its universal acceptance in stand-alone FAIMS devices, commercial FAIMS/MS systems have employed curved FAIMS geometries that could be interfaced to MS more effectively. Here we report a new planar (p-) FAIMS design with slit-shaped entrance and exit apertures that substantially increase ion transmission in and out of the analyzer. The front slit interface effectively couples p-FAIMS to multi-emitter electrospray ionization (ESI) sources, improving greatly the ion current introduced to the device. The back slit interface increases the transmission of ribbon-shaped ion beams output by the p-FAIMS to downstream stages such as a MS. Overall, the ion signal in ESI/FAIMS/MS analyses is raised by over an order of magnitude without affecting the FAIMS resolution.

  13. Chaotic dephasing in a double-slit scattering experiment.

    PubMed

    Levnajić, Zoran; Prosen, Tomaz

    2010-12-01

    We design a computational experiment in which a quantum particle tunnels into a billiard of variable shape and scatters out of it through a double-slit opening on the billiard's base. The interference patterns produced by the scattered probability currents for a range of energies are investigated in relation to the billiard's geometry which is connected to its classical integrability. Four billiards with hierarchical integrability levels are considered: integrable, pseudointegrable, weak-mixing, and strongly chaotic. In agreement with the earlier result by Casati and Prosen [Phys. Rev. A 72, 032111 (2005)], we find the billiard's integrability to have a crucial influence on the properties of the interference patterns. In the integrable case, most experiment outcomes are found to be consistent with the constructive interference occurring in the usual double-slit experiment. In contrast to this, nonintegrable billiards typically display asymmetric interference patterns of smaller visibility characterized by weakly correlated wave function values at the two slits. Our findings indicate an intrinsic connection between the classical integrability and the quantum dephasing, which is responsible for the destruction of interference.

  14. Path integrals, matter waves, and the double slit

    NASA Astrophysics Data System (ADS)

    Jones, Eric R.; Bach, Roger A.; Batelaan, Herman

    2015-11-01

    Basic explanations of the double slit diffraction phenomenon include a description of waves that emanate from two slits and interfere. The locations of the interference minima and maxima are determined by the phase difference of the waves. An optical wave, which has a wavelength λ and propagates a distance L, accumulates a phase of 2π L/λ . A matter wave, also having wavelength λ that propagates the same distance L, accumulates a phase of π L/λ , which is a factor of two different from the optical case. Nevertheless, in most situations, the phase difference, {{Δ }}\\varphi , for interfering matter waves that propagate distances that differ by {{Δ }}L, is approximately 2π {{Δ }}L/λ , which is the same value computed in the optical case. The difference between the matter and optical case hinders conceptual explanations of diffraction from two slits based on the matter-optics analogy. In the following article we provide a path integral description for matter waves with a focus on conceptual explanation. A thought experiment is provided to illustrate the validity range of the approximation {{Δ }}\\varphi ≈ 2π {{Δ }}L/λ .

  15. The neuronal repellent SLIT2 is a target for repression by EZH2 in prostate cancer.

    PubMed

    Yu, J; Cao, Q; Yu, J; Wu, L; Dallol, A; Li, J; Chen, G; Grasso, C; Cao, X; Lonigro, R J; Varambally, S; Mehra, R; Palanisamy, N; Wu, J Y; Latif, F; Chinnaiyan, A M

    2010-09-30

    The neuronal repellent SLIT2 is repressed in a number of cancer types primarily through promoter hypermethylation. SLIT2, however, has not been studied in prostate cancer. Through genome-wide location analysis we identified SLIT2 as a target of polycomb group (PcG) protein EZH2. The EZH2-containing polycomb repressive complexes bound to the SLIT2 promoter inhibiting its expression. SLIT2 was downregulated in a majority of metastatic prostate tumors, showing a negative correlation with EZH2. This repressed expression could be restored by methylation inhibitors or EZH2-suppressing compounds. In addition, a low level of SLIT2 expression was associated with aggressive prostate, breast and lung cancers. Functional assays showed that SLIT2 inhibited prostate cancer cell proliferation and invasion. Thus, this study showed for the first time the epigenetic silencing of SLIT2 in prostate tumors, and supported SLIT2 as a potential biomarker for aggressive solid tumors. Importantly, PcG-mediated repression may serve as a precursor for the silencing of SLIT2 by DNA methylation in cancer.

  16. Einstein-Bohr recoiling double-slit gedanken experiment performed at the molecular level

    NASA Astrophysics Data System (ADS)

    Liu, Xiao-Jing; Miao, Quan; Gel'Mukhanov, Faris; Patanen, Minna; Travnikova, Oksana; Nicolas, Christophe; Ågren, Hans; Ueda, Kiyoshi; Miron, Catalin

    2015-02-01

    Double-slit experiments illustrate the quintessential proof for wave-particle complementarity. If information is missing about which slit the particle has traversed, the particle, behaving as a wave, passes simultaneously through both slits. This wave-like behaviour and corresponding interference is absent if ‘which-slit’ information exists. The essence of Einstein-Bohr's debate about wave-particle duality was whether the momentum transfer between a particle and a recoiling slit could mark the path, thus destroying the interference. To measure the recoil of a slit, the slits should move independently. We showcase a materialization of this recoiling double-slit gedanken experiment by resonant X-ray photoemission from molecular oxygen for geometries near equilibrium (coupled slits) and in a dissociative state far away from equilibrium (decoupled slits). Interference is observed in the former case, while the electron momentum transfer quenches the interference in the latter case owing to Doppler labelling of the counter-propagating atomic slits, in full agreement with Bohr's complementarity.

  17. Slit2 inhibits glioma cell invasion in the brain by suppression of Cdc42 activity.

    PubMed

    Yiin, Jia-Jean; Hu, Bo; Jarzynka, Michael J; Feng, Haizhong; Liu, Kui-Wei; Wu, Jane Y; Ma, Hsin-I; Cheng, Shi-Yuan

    2009-12-01

    Acquisition of insidious invasiveness by malignant glioma cells involves multiple genetic alterations in signaling pathways. Slit2, a chemorepulsive factor, controls cell migration of neuronal and glial cells during development and inhibits chemotaxic migration of various types of cells in vitro. However, the role of Slit2 in vitro remains controversial, and the biological significance of Slit2 expression in cancer cell invasion in vivo has not yet been determined. In the present study, we characterized the effects of Slit2 expression on the migration and invasion of invasive glioma cells in vitro and in vivo. By reverse transcriptase polymerase chain reaction (PCR) analyses, Slit2 was found to be expressed at lower levels in primary glioma specimens and invasive glioma cells compared with normal human brain cells and astrocytes. Ectopic expression of Slit2 or treatment with recombinant Slit2 on glioma cells attenuates cell migration and invasion through inhibition of Cdc42 activity in vitro. Cellular depletion of Robo1, a cognate receptor for Slit2, prevented Slit2 inhibition of Cdc42 activity and glioma cell migration. In vivo, expression of Slit2 by invasive SNB19 glioma cells markedly inhibited glioma cell infiltration into the brain of mice. Moreover, impediment of glioma cell invasion by Slit2 did not affect the expression of N-cadherin and beta-catenin in glioma cells. These results provide the first evidence demonstrating that Slit2-Robo1 inhibits glioma invasion through attenuating Cdc42 activity in vitro and in the brain. Understanding the mechanisms of Slit2-Robo1 inhibition of glioma cell invasion will foster new treatments for malignant gliomas.

  18. Slit2 inactivates GSK3β to signal neurite outgrowth inhibition.

    PubMed

    Byun, Justin; Kim, Bo Taek; Kim, Yun Tai; Jiao, Zhongxian; Hur, Eun-Mi; Zhou, Feng-Quan

    2012-01-01

    Slit molecules comprise one of the four canonical families of axon guidance cues that steer the growth cone in the developing nervous system. Apart from their role in axon pathfinding, emerging lines of evidence suggest that a wide range of cellular processes are regulated by Slit, ranging from branch formation and fasciculation during neurite outgrowth to tumor progression and to angiogenesis. However, the molecular and cellular mechanisms downstream of Slit remain largely unknown, in part, because of a lack of a readily manipulatable system that produces easily identifiable traits in response to Slit. The present study demonstrates the feasibility of using the cell line CAD as an assay system to dissect the signaling pathways triggered by Slit. Here, we show that CAD cells express receptors for Slit (Robo1 and Robo2) and that CAD cells respond to nanomolar concentrations of Slit2 by markedly decelerating the rate of process extension. Using this system, we reveal that Slit2 inactivates GSK3β and that inhibition of GSK3β is required for Slit2 to inhibit process outgrowth. Furthermore, we show that Slit2 induces GSK3β phosphorylation and inhibits neurite outgrowth in adult dorsal root ganglion neurons, validating Slit2 signaling in primary neurons. Given that CAD cells can be conveniently manipulated using standard molecular biological methods and that the process extension phenotype regulated by Slit2 can be readily traced and quantified, the use of a cell line CAD will facilitate the identification of downstream effectors and elucidation of signaling cascade triggered by Slit.

  19. Detection of Slit2 promoter hypermethylation in tissue and serum samples from breast cancer patients.

    PubMed

    Kim, Ga-Eon; Lee, Kyung Hwa; Choi, Yoo Duk; Lee, Ji Shin; Lee, Jae Hyuk; Nam, Jong Hee; Choi, Chan; Park, Min Ho; Yoon, Jung Han

    2011-10-01

    Promoter hypermethylation has been shown to be a common mechanism for inactivation of tumor suppressor genes in breast cancer. The aim of this study was to investigate the prevalence of Slit2 promoter hypermethylation in both the tumor and serum samples of breast cancer patients with ductal carcinoma in situ (DCIS) or invasive breast carcinoma (IBC). The methylation status of Slit2 was investigated in 210 tissue samples (15 breast with no pathological findings, 26 DCIS, and 169 IBC samples) and 123 corresponding serum samples (15 breast with no pathological findings, 26 DCIS, and 82 IBC samples) using methylation-specific polymerase chain reaction. Immunohistochemical staining for Slit2 was also performed using tissue microarray blocks to determine whether Slit2 promoter hypermethylation correlated with loss of Slit2 expression. Slit2 promoter hypermethylation was not detected in breast tissue and serum samples from patients with no pathological findings. DCIS or IBC showed a statistically higher frequency of Slit2 promoter hypermethylation compared to breast with no pathological findings in both the tissue and serum samples; however, there were no statistically significant differences between DCIS and IBC samples. Similar Slit2 promoter hypermethylation patterns were seen in the tissue samples and corresponding serum specimens (p < 0.001). Slit2 promoter hypermethylation was associated with loss of Slit2 expression. These results suggest that Slit2 promoter hypermethylation appears to be responsible for functionally silencing Slit2 expression. Slit2 promoter hypermethylation may be considered as a possible serum marker for early detection of breast cancer.

  20. Slit2 inhibits growth and metastasis of fibrosarcoma and squamous cell carcinoma.

    PubMed

    Kim, Hee Kyung; Zhang, Hong; Li, Hui; Wu, Tsung-Teh; Swisher, Stephen; He, Donggou; Wu, Lizhi; Xu, Jianmin; Elmets, Craig A; Athar, Mohammad; Xu, Xìao-chun; Xu, Hui

    2008-12-01

    Slits are a group of secreted glycoproteins that play a role in the regulation of cell migration. Previous studies suggested that Slit2 might be a tumor-suppressor gene. However, it remained to be determined whether Slit2 suppressed tumor growth and metastasis in animal models. We showed that Slit2 expression was decreased or abolished in human esophageal squamous cell carcinomas (SCCs) compared to normal tissues by in situ hybridization. Stable transfection of human SCC A431 and fibrosarcoma HT1080 cells with Slit2 gene suppressed tumor growth in athymic nude mice. Apoptosis in Slit2-transfected tumors was increased, whereas proliferating cells were decreased, suggesting a mechanism for Slit2-mediated tumor suppression. This was supported by further analysis indicating that antiapoptotic molecules Bcl-2 and Bcl-xl and cell cycle molecules Cdk6 and Cyclin D1 were down-regulated in Slit2-transfected tumors. Furthermore, wound healing and Matrigel invasion assays showed that the transfection with Slit2 inhibited tumor cell migration and invasion. Slit2-transfected tumors showed a high level of keratin 8/18 and a low level of N-cadherin expression compared to empty vector-transfected tumors. More importantly, Slit2 transfection suppressed the metastasis of HT1080 tumor cells in lungs after intravenous inoculation. Collectively, our study has demonstrated that Slit2 inhibits tumor growth and metastasis of fibrosarcoma and SCC and that its effect on cell cycle and apoptosis signal pathways is an important mechanism for Slit2-mediated tumor suppression.

  1. A curved detection-slit to improve ERD (Elastic Recoil Detection) energy/depth resolution

    SciTech Connect

    Brice, D.K.; Doyle, B.L.

    1989-01-01

    Recoil atoms detected in Elastic Recoil Detection (ERD) experiments emerge from an initial collision area along cones of constant energy due to the cylindrical symmetry of the elastic scattering cross section. The constant energy cones therefore intercept planar slit plates placed before the detectors in conic sections. For ease of fabrication slits are typically configured as long narrow rectangles, and as a result energy resolution is adversely affected. It has been shown that the kinematic broadening caused by using rectangular slits is minimized when L = 2 (W z tan/Theta//sub recoil/)/sup 1/2/ where W is the slit width, L is the slit length, z is the slit-target distance and /Theta//sub recoil/ is the lab-frame recoil angle. The improved energy resolution which results when rectangular slits are replaced by appropriate curved slits is examined here. Formulas are given for the conic sections associated with the curved slits as a function of experimental geometry. When slit dimensions are small compared with the full extent of the conic section slit geometry can be accurately approximated as the arc of a circle with radius R/sub c/ = z tan/Theta//sub recoil/. Energy loss effects on the resolution are also accounted for in our treatment. The use of curved slits with L = 4 (W z tan/Theta//sub recoil/)/sup 1/2/ is shown to improve kinematic broadening by /approximately/50% as compared to optimized rectangular slits of the same area. 2 refs., 5 figs.

  2. MRI Scans

    MedlinePlus

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

  3. WBC scan

    MedlinePlus

    Leukocyte scan ... will be taken from one of your veins. White blood cells are separated from the rest of the blood ... 111. These cells are considered tagged. The tagged white blood cells are injected back into your body through a ...

  4. Precision optical slit for high heat load or ultra high vacuum

    DOEpatents

    Andresen, Nord C.; DiGennaro, Richard S.; Swain, Thomas L.

    1995-01-01

    This invention relates generally to slits used in optics that must be precisely aligned and adjusted. The optical slits of the present invention are useful in x-ray optics, x-ray beam lines, optical systems in which the entrance slit is critical for high wavelength resolution. The invention is particularly useful in ultra high vacuum systems where lubricants are difficult to use and designs which avoid the movement of metal parts against one another are important, such as monochrometers for high wavelength resolution with ultra high vacuum systems. The invention further relates to optical systems in which temperature characteristics of the slit materials is important. The present invention yet additionally relates to precision slits wherein the opposing edges of the slit must be precisely moved relative to a center line between the edges with each edge retaining its parallel orientation with respect to the other edge and/or the center line.

  5. Precision optical slit for high heat load or ultra high vacuum

    DOEpatents

    Andresen, N.C.; DiGennaro, R.S.; Swain, T.L.

    1995-01-24

    This invention relates generally to slits used in optics that must be precisely aligned and adjusted. The optical slits of the present invention are useful in x-ray optics, x-ray beam lines, optical systems in which the entrance slit is critical for high wavelength resolution. The invention is particularly useful in ultra high vacuum systems where lubricants are difficult to use and designs which avoid the movement of metal parts against one another are important, such as monochromators for high wavelength resolution with ultra high vacuum systems. The invention further relates to optical systems in which temperature characteristics of the slit materials is important. The present invention yet additionally relates to precision slits wherein the opposing edges of the slit must be precisely moved relative to a center line between the edges with each edge retaining its parallel orientation with respect to the other edge and/or the center line. 21 figures.

  6. Star scanner. [with a reticle with a pair of slits having differing separation

    NASA Technical Reports Server (NTRS)

    Gutshall, R. L.; Mcconaughey, R. T.; Volpe, F. A. (Inventor)

    1974-01-01

    A star scanner on a spin stabilized spacecraft is described which includes a reticle with a pair of slits having different separations as a function of the spacecraft vertical plane, to form a V slit. The time between a star image crossing one of the slits relative to a reference telemetry time provides an indication of azimuth angle. The time between the image crossing the two slits provides an indication of elevation angle of the star. If a star cluster is detected such that two stars pass the slits in less time than normally required for a single star to cross the two slits, an indication of the cluster occurrence is derived. Means are provided to prevent effective detection of large celestial bodies, such as the sun or moon.

  7. Neuronal chemorepellent Slit2 inhibits vascular smooth muscle cell migration by suppressing small GTPase Rac1 activation.

    PubMed

    Liu, Dong; Hou, Jie; Hu, Xing; Wang, Xuerong; Xiao, Yan; Mou, Yongshan; De Leon, Hector

    2006-03-01

    The Slits are secreted proteins with roles in axonal guidance and leukocyte migration. On binding to Robo receptors, Slit2 repels developing axons and inhibits leukocyte chemotaxis. Slit2 is cleaved into Slit2-N, a protein tightly binding to cell membranes, and Slit2-C, a diffusible fragment. In the present study, we characterized the functional role of Slit2-N in vascular smooth muscle cells (VSMCs) and the cell association properties of 2 truncated versions of Slit2-N. Here, we document for the first time that Slit2-N is a chemorepellent of VSMCs. Intact blood vessels expressed Slit2 and Robo receptors as demonstrated by immunohistochemistry and quantitative real time PCR. Recombinant Slit2-N prevented the platelet-derived growth factor (PDGF)-stimulated migration of VSMCs. Slit2-N also abrogated PDGF-mediated activation of small guanosine triphosphatase (GTPase) Rac1, a member of the Rho GTPase superfamily of proteins involved in regulating the actin cytoskeleton. Furthermore, Slit2-N inhibited the PDGF-induced formation of lamellipodia, a crucial cytoskeletal reorganization event for cell motility. Slit2-N had no effect on the PDGF-mediated increase in DNA synthesis determined by [3H]thymidine uptake, suggesting that VSMC growth is unaffected by Slit2. Analysis of 2 engineered Slit2-N fragments (Slit2-N/1118 and Slit2-N/1121) indicated that 3 amino acids upstream of the putative cleavage site (Arg1121, Thr1122) are involved in the association of Slit2-N to the cell membrane. Our data assign a novel functional role to Slit2 in vascular function and show that cell guidance mechanisms that operate in the developing central nervous system are conserved in VSMCs.

  8. [Purkinje images in slit lamp videography : Video article].

    PubMed

    Gellrich, M-M; Kandzia, C

    2016-09-01

    Reflexes that accompany every examination with the slit lamp are usually regarded as annoying and therefore do not receive much attention. In the video available online, clinical information "hidden" in the Purkinje images is analyzed according to our concept of slit lamp videography. In the first part of the video, the four Purkinje images which are reflections on the eye's optical surfaces are introduced for the phakic eye. In the pseudophakic eye, however, the refracting surfaces of the intraocular lens (IOL) have excellent optical properties and therefore form Purkinje images 3 and 4 of high quality. Especially the third Purkinje image from the anterior IOL surface, which is usually hardly visible in the phakic eye can be detected deep in the vitreous, enlarged through the eye's own optics like a magnifying glass. Its area of reflection can be used to visualize changes of the anterior segment at high contrast. The third Purkinje image carries valuable information about the anterior curvature and, thus, about the power of the IOL. If the same IOL type is implanted in a patient, often a difference between right and left of 0.5 diopter in its power can be detected by the difference in size of the respective third Purkinje image. In a historical excursion to the "prenatal phase" of the slit lamp in Uppsala, we show that our most important instrument in clinical work was originally designed for catoptric investigations (of specular reflections). Accordingly A. Gullstrand called it an ophthalmometric Nernst lamp. PMID:27558688

  9. Involvement of the SLIT/ROBO pathway in follicle development in the fetal ovary

    PubMed Central

    Dickinson, Rachel E; Hryhorskyj, Lynn; Tremewan, Hannah; Hogg, Kirsten; Thomson, Axel A; McNeilly, Alan S; Duncan, W Colin

    2010-01-01

    In humans and domestic mammals pivotal processes in ovary development, including primordial follicle assembly, occur prenatally. These events are essential for determining fertility in adult life however they remain poorly understood at the mechanistic level. In mammals the SLITs (SLIT1, SLIT2, SLIT3) and their ROBO (ROBO1, ROBO2, ROBO3/RIG-1, ROBO4/MAGIC ROBO) receptors regulate neural, leukocyte, vascular smooth muscle cell and endothelial cell migration. In addition the SLIT/ROBO pathway has functional roles in embryonic development and in the adult ovary by inhibiting cell migration and promoting apoptosis. We therefore characterised follicle formation and investigated the expression and localisation of the ROBO/SLIT pathway in the ovine fetal ovary. Using RT-PCR, we identified SLIT2, SLIT3, ROBO1, ROBO2 and ROBO4 in sheep ovaries harvested across gestation. The real-time quantitative PCR results implied that ROBO2 and ROBO4 expression were elevated during the early stages of follicle formation and stayed abundant during primordial follicle maturation (P<0.05). Immunohistochemistry examination demonstrated that ROBO1 was localised to the pre-granulosa cells while ROBO2, ROBO4 and SLIT2 were expressed in the oocytes of the developing primordial follicle. This indicates that in the fetal ovary SLIT-ROBO signalling may require an autocrine and paracrine interaction. Furthermore at the time of increased SLIT-ROBO expression there was a significant reduction in the number of proliferating oocytes in the developing ovary (P<0.0001). Overall these results suggest, for the first time, that the SLIT-ROBO pathway is expressed at the time of follicle formation during fetal ovary development. PMID:19900988

  10. Enhanced transmission of transverse electric waves through subwavelength slits in a thin metallic film.

    PubMed

    Ye, Yu Qian; Jin, Yi

    2009-09-01

    By adding an array of metallic cut wires, the transmission of transverse electric (TE) waves (the electric field is parallel to the slits) through subwavelength slits in a thin metallic film is significantly enhanced. An 800-fold enhanced transmission is obtained compared to the case without the cut wires. It is demonstrated that a TE incident wave is highly confined by the cut wires, due to the excitation of the electric dipolelike resonance, and then effectively squeezed into and through the subwavelength slits.

  11. Electron capture acceleration channel in a slit laser beam

    SciTech Connect

    Wang, P. X.; Scheid, W.; Ho, Y. K.

    2007-03-12

    Using numerical simulations, the authors find that the electrons can be captured and accelerated to high energies (GeV) in a slit laser beam with an intensity of I{lambda}{sup 2}{approx}10{sup 20} W/cm{sup 2} {mu}m{sup 2}, where {lambda} is the laser wavelength in units of {mu}m. The range of the optimum incident energy is very wide, even up to GeV. These results are of interest for experiments because the relatively low intensity can be achieved with present chirped pulse amplification technique and a wide range of incident energies means that a multistage acceleration is possible.

  12. Critical discharge of initially subcooled water through slits. [PWR; BWR

    SciTech Connect

    Amos, C N; Schrock, V E

    1983-09-01

    This report describes an experimental investigation into the critical flow of initially subcooled water through rectangular slits. The study of such flows is relevant to the prediction of leak flow rates from cracks in piping, or pressure vessels, which contain sufficient enthalpy that vaporization will occur if they are allowed to expand to the ambient pressure. Two new analytical models, which allow for the generation of a metastable liquid phase, are developed. Experimental results are compared with the predictions of both these new models and with a Fanno Homogeneous Equilibrium Model.

  13. Electrically switchable cholesteric gratings based on slit electrodes.

    PubMed

    Kuo, Chie-Tong; Chiang, Ru-Hsien; Wang, Chun-Yen; Hsieh, Ping-Hung; Lin, Yen-Ting; Lin, Chi-Huang; Huang, Chi-Yen

    2014-04-21

    An electrically switchable diffraction grating (ESDG) based on cholesteric liquid crystal (CLC) filled into the cell with slit electrodes is demonstrated in this study. On one hand, with low voltage, the ESDG has high second order diffraction efficiency because of the alternating planar and fingerprint textures. With high voltage, on the other hand, the ESDG has high first order diffraction efficiency because of the alternating planar and homeotropic textures. The first and second order diffraction efficiencies of ESDG are electrically swapped. The maximum diffraction efficiency of the ESDG is approximately 32% at each grating mode. PMID:24787860

  14. Momentum slits, collimators and masks in the SLC

    SciTech Connect

    Walz, D.R.; McFarlane, A.; Lewandowski, E.; Zabdyr, J.

    1989-04-01

    The high specific power densities in the SLC give rise to a multitude of challenging problems in collimation and momentum analysis, beam containment, machine protection and background control. The results of an extensive program to develop most of the devices deemed necessary for operation of the arcs matching sections and the final focus region are presented. Emphasis is placed on materials selection and on unique features of remotely adjustable slits and halo clipper collimators which have to operate with great precision in a high-radiation, ultra-high vacuum environment. Also covered are solutions for a few fixed aperture machine protection collimators. 7 refs., 5 figs.

  15. An error compensation method for a linear array sun sensor with a V-shaped slit

    NASA Astrophysics Data System (ADS)

    Fan, Qiao-yun; Tan, Xiao-feng

    2015-11-01

    Existing methods of improving measurement accuracy, such as polynomial fitting and increasing pixel numbers, cannot guarantee high precision and good miniaturization specifications of a microsun sensor at the same time. Therefore, a novel integrated and accurate error compensation method is proposed. A mathematical error model is established according to the analysis results of all the contributing factors, and the model parameters are calculated through multi-sets simultaneous calibration. The numerical simulation results prove that the calibration method is unaffected by installation errors introduced by the calibration process, and is capable of separating the sensor’s intrinsic and extrinsic parameters precisely, and obtaining accurate and robust intrinsic parameters. In laboratorial calibration, the calibration data are generated by using a two-axis rotation table and a sun simulator. The experimental results show that owing to the proposed error compensation method, the sun sensor’s measurement accuracy is improved by 30 times throughout its field of view (±60°  ×  ±60°), with a RMS error of 0.1°.

  16. Slit2 expression and its correlation with subcellular localization of β-catenin in gastric cancer.

    PubMed

    Shi, Rongliang; Liu, Weiyan; Liu, Bingya; Xu, Ziping; Chen, Liping; Zhang, Ziping

    2013-10-01

    Gastric cancer is the fourth most common cancer worldwide. Several signaling pathways are involved in gastric cancer development and progression. Slit2 was recently found to be involved in cancer; however, its expression pattern in gastric cancer has not been discovered yet. In the present study, we investigated the expression of Slit2 in human gastric cancer and its correlation with the expression and subcellular localization of β-catenin. Immunohistochemistry (IHC) staining revealed that Slit2 was highly expressed in human gastric cancer tissues, while it was low or weakly expressed in normal gastric tissues. The differences in clinicopathological features between different groups were determined using Pearson's χ2 test. Slit2 levels were significantly associated with differentiation, Lauren's classification, lymph node metastasis and TNM staging. Slit2 levels were positively correlated with β-catenin level in gastric cancer tissues and cell lines. High levels of Slit2 were correlated with the membrane localization of β-catenin, and low levels of Slit2 were correlated with nuclear translocation of β-catenin in both gastric cancer tissues and cell lines assayed by IHC and immunofluorescence staining, respectively. Our data suggest that Slit2 was highly expressed in gastric cancer patients with less advanced clinicopathological features. Slit2 levels were correlated with β-catenin level and subcellular localization.

  17. Maximal Expression of the Evolutionarily Conserved Slit2 Gene Promoter Requires Sp1.

    PubMed

    Saunders, Jacquelyn; Wisidagama, D Roonalika; Morford, Travis; Malone, Cindy S

    2016-08-01

    Slit2 is a neural axon guidance and chemorepellent protein that stimulates motility in a variety of cell types. The role of Slit2 in neural development and neoplastic growth and migration has been well established, while the genetic mechanisms underlying regulation of the Slit2 gene have not. We identified the core and proximal promoter of Slit2 by mapping multiple transcriptional start sites, analyzing transcriptional activity, and confirming sequence homology for the Slit2 proximal promoter among a number of species. Deletion series and transient transfection identified the Slit2 proximal promoter as within 399 base pairs upstream of the start of transcription. A crucial region for full expression of the Slit2 proximal promoter lies between 399 base pairs and 296 base pairs upstream of the start of transcription. Computer modeling identified three transcription factor-binding consensus sites within this region, of which only site-directed mutagenesis of one of the two identified Sp1 consensus sites inhibited transcriptional activity of the Slit2 proximal promoter (-399 to +253). Bioinformatics analysis of the Slit2 proximal promoter -399 base pair to -296 base pair region shows high sequence conservation over twenty-two species, and that this region follows an expected pattern of sequence divergence through evolution.

  18. Slit2 signaling through Robo1 and Robo2 is required for retinal neovascularization.

    PubMed

    Rama, Nicolas; Dubrac, Alexandre; Mathivet, Thomas; Ní Chárthaigh, Róisín-Ana; Genet, Gael; Cristofaro, Brunella; Pibouin-Fragner, Laurence; Ma, Le; Eichmann, Anne; Chédotal, Alain

    2015-05-01

    Ocular neovascular diseases are a leading cause of blindness. Vascular endothelial growth factor (VEGF) blockade improves vision, but not all individuals respond to anti-VEGF treatment, making additional means to prevent neovascularization necessary. Slit-family proteins (Slits) are ligands of Roundabout (Robo) receptors that repel developing axons in the nervous system. Robo1 expression is altered in ocular neovascular diseases, and previous in vitro studies have reported both pro- and anti-angiogenic effects of Slits. However, genetic evidence supporting a role for Slits in ocular neovascularization is lacking. Here we generated conditional knockout mice deficient in various Slit and Robo proteins and found that Slit2 potently and selectively promoted angiogenesis via Robo1 and Robo2 in mouse postnatal retina and in a model of ocular neovascular disease. Mechanistically, Slit2 acting through Robo1 and Robo2 promoted the migration of endothelial cells. These receptors are required for both Slit2- and VEGF-induced Rac1 activation and lamellipodia formation. Thus, Slit2 blockade could potentially be used therapeutically to inhibit angiogenesis in individuals with ocular neovascular disease.

  19. The SLIT-ROBO pathway: a regulator of cell function with implications for the reproductive system.

    PubMed

    Dickinson, Rachel E; Duncan, W Colin

    2010-04-01

    The secreted SLIT glycoproteins and their Roundabout (ROBO) receptors were originally identified as important axon guidance molecules. They function as a repulsive cue with an evolutionarily conserved role in preventing axons from migrating to inappropriate locations during the assembly of the nervous system. In addition the SLIT-ROBO interaction is involved in the regulation of cell migration, cell death and angiogenesis and, as such, has a pivotal role during the development of other tissues such as the lung, kidney, liver and breast. The cellular functions that the SLIT/ROBO pathway controls during tissue morphogenesis are processes that are dysregulated during cancer development. Therefore inactivation of certain SLITs and ROBOs is associated with advanced tumour formation and progression in disparate tissues. Recent research has indicated that the SLIT/ROBO pathway could also have important functions in the reproductive system. The fetal ovary expresses most members of the SLIT and ROBO families. The SLITs and ROBOs also appear to be regulated by steroid hormones and regulate physiological cell functions in adult reproductive tissues such as the ovary and endometrium. Furthermore several SLITs and ROBOs are aberrantly expressed during the development of ovarian, endometrial, cervical and prostate cancer. This review will examine the roles this pathway could have in the development, physiology and pathology of the reproductive system and highlight areas for future research that could further dissect the influence of the SLIT/ROBO pathway in reproduction.

  20. Fraunhofer diffraction of light with orbital angular momentum by a slit.

    PubMed

    Ferreira, Queila S; Jesus-Silva, Alcenísio J; Fonseca, Eduardo J S; Hickmann, Jandir M

    2011-08-15

    We study the Fraunhofer diffraction problem while taking into account the orbital angular momentum of light. In this case, the phase singularity of the light beam is incident on the slit in two different cases: in one, it is incident slightly above the slit, and in the other it is centered on the slit. We observed that the symmetry and the fringe formation in the interference pattern strongly depend on the amount of orbital angular momentum and the slit position in relation to the beam.

  1. Slit2 signaling through Robo1 and Robo2 is required for retinal neovascularization

    PubMed Central

    Rama, Nicolas; Dubrac, Alexandre; Mathivet, Thomas; Chárthaigh, Róisín-Ana Ní; Genet, Gael; Cristofaro, Brunella; Pibouin-Fragner, Laurence; Ma, Le; Eichmann, Anne; Chédotal, Alain

    2016-01-01

    Ocular neovascular diseases are a leading cause of blindness. Vascular endothelial growth factor (VEGF) blockade improves vision, but not all individuals respond to anti-VEGF treatment, making additional means to prevent neovascularization necessary. Slit-family proteins (Slits) are ligands of Roundabout (Robo) receptors that repel developing axons in the nervous system. Robo1 expression is altered in ocular neovascular diseases, and previous in vitro studies have reported both pro- and anti-angiogenic effects of Slits. However, genetic evidence supporting a role for Slits in ocular neovascularization is lacking. Here we generated conditional knockout mice deficient in various Slit and Robo proteins and found that Slit2 potently and selectively promoted angiogenesis via Robo1 and Robo2 in mouse postnatal retina and in a model of ocular neovascular disease. Mechanistically, Slit2 acting through Robo1 and Robo2 promoted the migration of endothelial cells. These receptors are required for both Slit2- and VEGF-induced Rac1 activation and lamellipodia formation. Thus, Slit2 blockade could potentially be used therapeutically to inhibit angiogenesis in individuals with ocular neovascular disease. PMID:25894826

  2. Slit Modulates Cerebrovascular Inflammation and Mediates Neuroprotection Against Global Cerebral Ischemia

    PubMed Central

    Altay, Tamer; McLaughlin, BethAnn; Wu, Jane Y.; Park, T.S.; Gidday, Jeffrey M.

    2008-01-01

    Cerebrovascular inflammation contributes to secondary brain injury following ischemia. Recent in vitro studies of cell migration and molecular guidance mechanisms have indicated that the Slit family of secreted proteins can exert repellant effects on leukocyte recruitment in response to chemoattractants. Utilizing intravital microscopy, we addressed the role of Slit in modulating leukocyte dynamics in the mouse cortical venular microcirculation in vivo following TNFα application or global cerebral ischemia. We also studied whether Slit affected neuronal survival in the mouse global ischemia model as well as in mixed neuronal-glial cultures subjected to oxygen-glucose deprivation. We found that systemically administered Slit significantly attenuated cerebral microvessel leukocyte-endothelial adherence occurring 4 h after TNFα and 24 h after global cerebral ischemia. Administration of RoboN, the soluble receptor for Slit, exacerbated the acute chemotactic response to TNFα. These findings are indicative of a tonic repellant effect of endogenous Slit in brain under acute proinflammatory conditions. Three days of continuous systemic administration of Slit following global ischemia significantly attenuated the delayed neuronal death of hippocampal CA1 pyramidal cells. Moreover, Slit abrogated neuronal death in mixed neuronal-glial cultures exposed to oxygen-glucose deprivation. The ability of Slit to reduce the recruitment of immune cells to ischemic brain and to provide cytoprotective effects suggests that this protein may serve as a novel anti-inflammatory and neuroprotective target for stroke therapy. PMID:17714707

  3. Experimental evidence of wave chaos from a double slit experiment with water surface waves.

    PubMed

    Tang, Yunfei; Shen, Yifeng; Yang, Jiong; Liu, Xiaohan; Zi, Jian; Li, Baowen

    2008-10-01

    In this paper, we report experimental evidence of wave chaos using the double slit water surface wave experiment. We demonstrate that classical dynamics of a domain manifests itself in the interference patterns after the diffraction behind the double slit. For a domain whose classical dynamics is integrable clear interference fringes can be observed behind the double slits; for a domain whose classical dynamics is chaotic, however, interference fringes can totally disappear. Our experimental results clearly demonstrate that the centuries-old double slit experiment can render an excellent tool to observe the manifestations of wave chaos.

  4. Slit2/Robo1 signaling promotes intestinal tumorigenesis through Src-mediated activation of the Wnt/β-catenin pathway.

    PubMed

    Zhang, Qian-Qian; Zhou, Da-Lei; Lei, Yan; Zheng, Li; Chen, Sheng-Xia; Gou, Hong-Ju; Gu, Qu-Liang; He, Xiao-Dong; Lan, Tian; Qi, Cui-Ling; Li, Jiang-Chao; Ding, Yan-Qing; Qiao, Liang; Wang, Li-Jing

    2015-02-20

    Slit2 is often overexpressed in cancers. Slit2 is a secreted protein that binds to Roundabout (Robo) receptors to regulate cell growth and migration. Here, we employed several complementary mouse models of intestinal cancers, including the Slit2 transgenic mice, the ApcMin/+ spontaneous intestinal adenoma mouse model, and the DMH/DSS-induced colorectal carcinoma model to clarify function of Slit2/Robo1 signaling in intestinal tumorigenesis. We showed that Slit2 and Robo1 are overexpressed in intestinal tumors and may contribute to tumor generation. The Slit2/Robo1 signaling can induce precancerous lesions of the intestine and tumor progression. Ectopic expression of Slit2 activated Slit2/Robo1 signaling and promoted tumorigenesis and tumor growth. This was mediated in part through activation of the Src signaling, which then down-regulated E-cadherin, thereby activating Wnt/β-catenin signaling. Thus, Slit2/Robo1 signaling is oncogenic in intestinal tumorigenesis.

  5. Knockdown of Slit2 promotes growth and motility in gastric cancer cells via activation of AKT/β-catenin.

    PubMed

    Shi, Rongliang; Yang, Zhen; Liu, Weiyan; Liu, Bingya; Xu, Ziping; Zhang, Ziping

    2014-02-01

    We previously showed that Slit2 was highly expressed in gastric cancer tissues that exhibit less advanced clinicopathological features, suggesting a tumor suppressor role for Slit2. In the present study, we investigated the effects of Slit2 knockdown on gastric cancer cells. Slit2-specific shRNAs were used to generate Slit2-knockdown SGC-7901 gastric cancer cells. Cell proliferation assay, Annexin V/PI double staining and cell cycle analysis were used to investigate the role of Slit2 knockdown in cell growth. Wound-healing and in vitro migration/invasion assays were performed. Subcutaneous tumor formation and peritoneal spreading in nude mice were employed to examine the in vivo effects of Slit2 knockdown. Cell signaling changes induced by Slit2 knockdown were analyzed by immunoblotting. Slit2 knockdown increased gastric cancer cell growth in monolayer and soft agar/Matrigel 3D culture. Slit2 knockdown inhibited apoptosis but did not alter cell cycle progression. Slit2-knockdown cells formed larger tumors and produced more peritoneal metastatic nodules in nude mice. Slit2 knockdown increased AKT phosphorylation, activated anti-apoptotic signaling, suppressed GSK3β activity and induced β-catenin activation. Blocking the effects of PI3K/AKT using pharmacological inhibitors abolished the ability of Slit2 knockdown to induce apoptosis resistance and cell migration/invasion. These results indicate that Slit2 knockdown promotes gastric cancer growth and metastasis through activation of the AKT/β‑catenin-mediated signaling pathway.

  6. Testing Quantum Mechanics using a Triple slit experiment

    NASA Astrophysics Data System (ADS)

    Sinha, Urbasi; Couteau, Christophe; Jennewein, Thomas; Sorkin, Rafael; Laflamme, Raymond; Weihs, Gregor

    2010-03-01

    As one of the postulates of quantum mechanics, Born's rule tells us how to get probabilities for experimental outcomes from the complex wavefunction of the system. It's quadratic nature entails that interference occurs in pairs of paths. An experiment is in progress in our laboratory that sets out to test the correctness of Born's rule by testing for the presence or absence of genuine three-path interference [1]. This is done using single photons and a three slit aperture. Although the Born rule has been indirectly verified to high accuracy in other experiments, the consequences of a detection of even a small three-way interference in the Quantum mechanical null prediction are tremendous. If a non-zero result were to be obtained, it would mean that Quantum Mechanics is only approximate, in the same way that the double slit experiment proves that classical physics is only an approximation to the true law of nature. This would give us an important hint on how to generalize Quantum Mechanics and open a new window to the world. Some preliminary observations have been reported in reference [2]. In this talk, I will show results that bound the possible violation of the second sum rule and will point out ways to obtain a tighter experimental bound. [1] R. D. Sorkin, Mod. Phys. Lett. A 9, 3119 (1994). [2] U. Sinha et al, in Foundations of Probability and Physics-5, A I P Conference Proceedings, Vol. 1101, pp. 200-207, New-York (2009)

  7. High resolution hyperspectral imaging with a high throughput virtual slit

    NASA Astrophysics Data System (ADS)

    Gooding, Edward A.; Gunn, Thomas; Cenko, Andrew T.; Hajian, Arsen R.

    2016-05-01

    Hyperspectral imaging (HSI) device users often require both high spectral resolution, on the order of 1 nm, and high light-gathering power. A wide entrance slit assures reasonable étendue but degrades spectral resolution. Spectrometers built using High Throughput Virtual Slit™ (HTVS) technology optimize both parameters simultaneously. Two remote sensing use cases that require high spectral resolution are discussed. First, detection of atmospheric gases with intrinsically narrow absorption lines, such as hydrocarbon vapors or combustion exhaust gases such as NOx and CO2. Detecting exhaust gas species with high precision has become increasingly important in the light of recent events in the automobile industry. Second, distinguishing reflected daylight from emission spectra in the visible and NIR (VNIR) regions is most easily accomplished using the Fraunhofer absorption lines in solar spectra. While ground reflectance spectral features in the VNIR are generally quite broad, the Fraunhofer lines are narrow and provide a signature of intrinsic vs. extrinsic illumination. The High Throughput Virtual Slit enables higher spectral resolution than is achievable with conventional spectrometers by manipulating the beam profile in pupil space. By reshaping the instrument pupil with reflective optics, HTVS-equipped instruments create a tall, narrow image profile at the exit focal plane, typically delivering 5X or better the spectral resolution achievable with a conventional design.

  8. Podocin localizes in the kidney to the slit diaphragm area.

    PubMed

    Roselli, Séverine; Gribouval, Olivier; Boute, Nicolas; Sich, Mireille; Benessy, France; Attié, Tania; Gubler, Marie-Claire; Antignac, Corinne

    2002-01-01

    We recently cloned a novel gene, NPHS2, involved in autosomal recessive steroid-resistant nephrotic syndrome. This gene encodes a novel podocyte protein, podocin. Given its similarity with the stomatin family proteins, podocin is predicted to be an integral membrane protein with a single membrane domain forming a hairpin-like structure placing both N- and C-termini in the cytosol. Here, we show by in situ hybridization, that during development, the NPHS2 transcript is first expressed in mesonephric podocytes from the S-shaped body and, later, in the metanephric kidney, in the future podocytes at the late S-shaped body stage. In the mature kidney, NPHS2 is exclusively expressed in the podocytes of mature glomeruli. We generated rabbit polyclonal antibodies against fusion proteins derived from the N- and the C-terminal regions of podocin which detected a single band of 49-kd in transfected HEK293 cell lysates by immunoprecipitation and Western blotting. By immunohistology, podocin was detected in podocytes from the early capillary loop stage in the developing nephrons, and at the basal pole, along the GBM, in mature glomeruli. By electron microscopy, we demonstrate that podocin is facing the slit diaphragm with its two ends in the cytoplasm of the foot processes, in agreement with its predicted structure. Our results suggest that podocin could serve to anchor directly or indirectly components of the slit diaphragm to the cytoskeleton.

  9. Surface plasmon polariton analogue to Young's double-slit experiment.

    PubMed

    Zia, Rashid; Brongersma, Mark L

    2007-07-01

    When a light wave strikes a metal film it can, under appropriate conditions, excite a surface plasmon polariton (SPP)--a surface electromagnetic wave that is coupled to the free electrons in the metal. Such SPPs are involved in a wide range of phenomena, including nanoscale optical waveguiding, perfect lensing, extraordinary optical transmission, subwavelength lithography and ultrahigh-sensitivity biosensing. However, before the full potential of technology based on SPPs (termed 'plasmonics') can be realized, many fundamental questions regarding the interaction between light and matter at the nanoscale need to be answered. For over 200 years, Young's double-slit experiment has been a valuable pedagogical tool for demonstrating the wave nature of light. Here, we perform a double-slit experiment with SPPs to reveal the strong analogy between SPP propagation along the surface of metallic structures and light propagation in conventional dielectric components (such as glass waveguides). This allows us to construct a general framework to describe the propagation, diffraction and interference of SPPs. It also suggests that there is an effective diffraction limit for the lateral confinement of SPPs on metal stripe waveguides, and justifies the use of well-developed concepts from conventional optics and photonics in the design of new plasmonic devices.

  10. Young's double-slit experiment: noise-resolution duality.

    PubMed

    Nesterets, Yakov I; Gureyev, Timur E

    2015-02-01

    Statistical aspects of Young's double-slit diffraction experiment are analysed quantitatively. It is shown that the signal-to-noise ratio and the spatial resolution in the detected diffraction pattern satisfy a duality relationship which implies that both of them cannot be improved simultaneously beyond a certain limit if the total number of particles forming the image is fixed. As a consequence of this duality, it is possible to estimate the minimal number of particles that have to be detected in order for two slits separated by a given distance to be resolved with a confidence level corresponding to a pre-defined signal-to-noise ratio, e.g. according to the Rose criterion. These results are related to the recently introduced imaging system quality characteristic which combines the spatial resolution and the noise sensitivity, and allows one to estimate the efficiency with which imaging quanta are utilised in a system to deliver maximal amount of information about the imaged object. The presented results can be useful for applications where the imaging quanta are at a premium or where minimization of the radiation dose is important.

  11. Adaptive SPECT imaging with crossed-slit apertures

    PubMed Central

    Durko, Heather L.; Furenlid, Lars R.

    2015-01-01

    Preclinical single-photon emission computed tomography (SPECT) is an essential tool for studying the progression, response to treatment, and physiological changes in small animal models of human disease. The wide range of imaging applications is often limited by the static design of many preclinical SPECT systems. We have developed a prototype imaging system that replaces the standard static pinhole aperture with two sets of movable, keel-edged copper-tungsten blades configured as crossed (skewed) slits. These apertures can be positioned independently between the object and detector, producing a continuum of imaging configurations in which the axial and transaxial magnifications are not constrained to be equal. We incorporated a megapixel silicon double-sided strip detector to permit ultrahigh-resolution imaging. We describe the configuration of the adjustable slit aperture imaging system and discuss its application toward adaptive imaging, and reconstruction techniques using an accurate imaging forward model, a novel geometric calibration technique, and a GPU-based ultra-high-resolution reconstruction code. PMID:26190884

  12. Human placental multipotent mesenchymal stromal cells modulate placenta angiogenesis through Slit2-Robo signaling.

    PubMed

    Chen, Cheng-Yi; Tsai, Chin-Han; Chen, Chia-Yu; Wu, Yi-Hsin; Chen, Chie-Pein

    2016-03-01

    The objective of this study was to investigate whether human placental multipotent mesenchymal stromal cell (hPMSC)-derived Slit2 and endothelial cell Roundabout (Robo) receptors are involved in placental angiogenesis. The hPMSC-conditioned medium and human umbilical vein endothelial cells were studied for Slit2 and Robo receptor expression by immunoassay and RT-PCR. The effect of the conditioned medium of hPMSCs with or without Slit2 depletion on endothelial cells was investigated by in vitro angiogenesis using growth factor-reduced Matrigel. hPMSCs express Slit2 and both Robo1 and Robo4 are present in human umbilical vein endothelial cells. Human umbilical vein endothelial cells do not express Robo2 and Robo3. The hPMSC-conditioned medium and Slit2 recombinant protein significantly inhibit the endothelial cell migration, but not by the hPMSC-conditioned medium with Slit2 depletion. The hPMSC-conditioned medium and Slit2 significantly enhance endothelial tube formation with increased cumulated tube length, polygonal network number and vessel branching point number compared to endothelial cells alone. The tube formation is inhibited by the depletion of Slit2 from the conditioned medium, or following the expression of Robo1, Robo4, and both receptor knockdown using small interfering RNA. Furthermore, co-immunoprecipitation reveals Slit2 binds to Robo1 and Robo4. Robo1 interacts and forms a heterodimeric complex with Robo4. These results suggest the implication of both Robo receptors with Slit2 signaling, which is involved in endothelial cell angiogenesis. Slit2 in the conditioned medium of hPMSCs has functional effect on endothelial cells and may play a role in placental angiogenesis.

  13. The Neurorepellent Slit2 Inhibits Postadhesion Stabilization of Monocytes Tethered to Vascular Endothelial Cells.

    PubMed

    Mukovozov, Ilya; Huang, Yi-Wei; Zhang, Qiuwang; Liu, Guang Ying; Siu, Allan; Sokolskyy, Yaroslav; Patel, Sajedabanu; Hyduk, Sharon J; Kutryk, Michael J B; Cybulsky, Myron I; Robinson, Lisa A

    2015-10-01

    The secreted neurorepellent Slit2, acting through its transmembrane receptor, Roundabout (Robo)-1, inhibits chemotaxis of varied cell types, including leukocytes, endothelial cells, and vascular smooth muscle cells, toward diverse attractants. The role of Slit2 in regulating the steps involved in recruitment of monocytes in vascular inflammation is not well understood. In this study, we showed that Slit2 inhibited adhesion of monocytic cells to activated human endothelial cells, as well as to immobilized ICAM-1 and VCAM-1. Microfluidic live cell imaging showed that Slit2 inhibited the ability of monocytes tethered to endothelial cells to stabilize their actin-associated anchors and to resist detachment in response to increasing shear forces. Transfection of constitutively active plasmids revealed that Slit2 inhibited postadhesion stabilization of monocytes on endothelial cells by preventing activation of Rac1. We further found that Slit2 inhibited chemotaxis of monocytes toward CXCL12 and CCL2. To determine whether Slit2 and Robo-1 modulate pathologic monocyte recruitment associated with vascular inflammation and cardiovascular disease, we tested PBMC from patients with coronary artery disease. PBMC from these patients had reduced surface levels of Robo-1 compared with healthy age- and sex-matched subjects, and Slit2 failed to inhibit chemotaxis of PBMC of affected patients, but not healthy control subjects, toward CCL2. Furthermore, administration of Slit2 to atherosclerosis-prone LDL receptor-deficient mice inhibited monocyte recruitment to nascent atherosclerotic lesions. These results demonstrate that Slit2 inhibits chemotaxis of monocytes, as well as their ability to stabilize adhesions and resist detachment forces. Slit2 may represent a powerful new tool to inhibit pathologic monocyte recruitment in vascular inflammation and atherosclerosis.

  14. The axonal repellent, Slit2, inhibits directional migration of circulating neutrophils.

    PubMed

    Tole, Soumitra; Mukovozov, Ilya M; Huang, Yi-Wei; Magalhaes, Marco A O; Yan, Ming; Crow, Min Rui; Liu, Guang Ying; Sun, Chun Xiang; Durocher, Yves; Glogauer, Michael; Robinson, Lisa A

    2009-12-01

    In inflammatory diseases, circulating neutrophils are recruited to sites of injury. Attractant signals are provided by many different chemotactic molecules, such that blockade of one may not prevent neutrophil recruitment effectively. The Slit family of secreted proteins and their transmembrane receptor, Robo, repel axonal migration during CNS development. Emerging evidence shows that by inhibiting the activation of Rho-family GTPases, Slit2/Robo also inhibit migration of other cell types toward a variety of chemotactic factors in vitro and in vivo. The role of Slit2 in inflammation, however, has been largely unexplored. We isolated primary neutrophils from human peripheral blood and mouse bone marrow and detected Robo-1 expression. Using video-microscopic live cell tracking, we found that Slit2 selectively impaired directional migration but not random movement of neutrophils toward fMLP. Slit2 also inhibited neutrophil migration toward other chemoattractants, namely C5a and IL-8. Slit2 inhibited neutrophil chemotaxis by preventing chemoattractant-induced actin barbed end formation and cell polarization. Slit2 mediated these effects by suppressing inducible activation of Cdc42 and Rac2 but did not impair activation of other major kinase pathways involved in neutrophil migration. We further tested the effects of Slit2 in vivo using mouse models of peritoneal inflammation induced by sodium periodate, C5a, and MIP-2. In all instances, Slit2 reduced neutrophil recruitment effectively (P<0.01). Collectively, these data demonstrate that Slit2 potently inhibits chemotaxis but not random motion of circulating neutrophils and point to Slit2 as a potential new therapeutic for preventing localized inflammation.

  15. UNREVIEWED DISPOSAL QUESTION EVALUATION: CENTER SLIT TRENCHES ONE THROUGH FIVE OPERATIONAL COVERS REANALYSIS

    SciTech Connect

    Smith, F.; Swingle, R.

    2011-05-26

    Operational inventory limits for the disposal of solid low-level waste in Slit Trenches 1-7 were established by the Special Analysis (SA) performed by Collard and Hamm (2008). To determine disposal limits for the Slit Trenches, the SA followed the methodology used in the 2008 PA (WSRC, 2008) which assumed that the inventories in each trench were instantaneously placed in 12/1995, which is the date when SLIT1 began operation. The 2008 SA analyzed the impact from placing storm-water runoff covers simultaneously over Slit Trenches 1-7 at 5, 10 and 15 years after the inventory was introduced. To include a measure of conservatism in the limits, the lowest of the limits calculated for any storm-water runoff cover placement time or that calculated in the original 2008 PA was chosen as the operational limit for each radionuclide. Through the availability of funding provided by the American Recovery and Reinvestment Act (ARRA), storm-water runoff covers were placed over Slit Trenches 1-5 in December 2010. SRNL was requested to perform a UDQE for this accelerated action. Table 1 below lists the operational dates for Slit Trenches 1-5 and the time elapsed between when the first waste package was disposed in each Slit Trench and when the storm-water runoff covers were placed. As shown in Table 1, SLIT1 was covered 15.0 years after the date of the first waste package disposal. SLIT2 was covered 9.2 years after the date of the first waste package disposal in SLIT2 which falls within the window of {+-} 1.0 year within which the 2008 SA cover time analysis was assumed to be valid (Crowley and Butcher, 2008). Therefore, the analysis of SLIT1 and SLIT2 in the 2008 SA is considered adequate. However, the cover timings for SLIT3, SLIT4 and SLIT5 are from 2.2 to 1.6 years beyond the nearest cover time of 5 years assumed in the 2008 SA analysis and fall outside of the acceptable one-year margin. Therefore, an additional study was conducted by Collard et al. (2011) that assessed the

  16. Perineal scanning.

    PubMed

    Jeanty, P; d'Alton, M; Romero, R; Hobbins, J C

    1986-10-01

    Although various techniques have been described to aid in the ultrasound diagnosis of placenta previa and incompetent cervix, these maneuvers depend on the precise identification of the internal cervical os, a feat which is notoriously difficult to accomplish consistently. In an attempt to get a closer view of the cervix we tried another approach. This simple technique of perineal scanning has the potential to help considerably with these problems. PMID:3530265

  17. Detection optimization using linear systems analysis of a coded aperture laser sensor system

    SciTech Connect

    Gentry, S.M.

    1994-09-01

    Minimum detectable irradiance levels for a diffraction grating based laser sensor were calculated to be governed by clutter noise resulting from reflected earth albedo. Features on the earth surface caused pseudo-imaging effects on the sensor`s detector arras that resulted in the limiting noise in the detection domain. It was theorized that a custom aperture transmission function existed that would optimize the detection of laser sources against this clutter background. Amplitude and phase aperture functions were investigated. Compared to the diffraction grating technique, a classical Young`s double-slit aperture technique was investigated as a possible optimized solution but was not shown to produce a system that had better clutter-noise limited minimum detectable irradiance. Even though the double-slit concept was not found to have a detection advantage over the slit-grating concept, one interesting concept grew out of the double-slit design that deserved mention in this report, namely the Barker-coded double-slit. This diffractive aperture design possessed properties that significantly improved the wavelength accuracy of the double-slit design. While a concept was not found to beat the slit-grating concept, the methodology used for the analysis and optimization is an example of the application of optoelectronic system-level linear analysis. The techniques outlined here can be used as a template for analysis of a wide range of optoelectronic systems where the entire system, both optical and electronic, contribute to the detection of complex spatial and temporal signals.

  18. Tape edge study in a linear tape drive with single-flanged guides

    NASA Astrophysics Data System (ADS)

    Goldade, Anton V.; Bhushan, Bharat

    2004-05-01

    Improved tape guiding and tape dimensional stability are essential for magnetic tape linear recoding formats to take advantage of vastly increased track density and thereby achieve higher storage capacities. Tape guiding is dependent on numerous parameters, such as type of the guides and tape path geometry, quality of virgin tape edge, drive operating parameters (e.g., tape speed and tape tension), mechanical properties of the tape, and tape geometry (e.g., cupping and curvature). The objective of the present study is to evaluate guiding and tribological performance of single-flanged guides with porous air bearings in a linear tape drive. A comparison of guiding performance of the dual flanged stationary guides and single-flanged guides with porous air bearings is performed. The effect of tape path geometry, drive operating conditions (speed and tension) and tape edge quality of factory-slit tapes on tape guiding are evaluated during short-term tests. A lateral force measurement technique is used to measure the force exerted by the tape edge on the guide flange. A technique for the lateral tape motion measurement is used to study the effect of continuous sliding on tape guiding. Wear tests up to 5000 cycles are conducted and coefficient of friction and lateral tape motion are monitored to study the effect of drive operating conditions (speed and tension), edge quality of factory-slit tapes and tape thickness on tape guiding. Optical microscopy, atomic force microscopy and scanning electron microscopy are employed to study and quantify the quality of tape edge.

  19. Recombinant N-Terminal Slit2 Inhibits TGF-β-Induced Fibroblast Activation and Renal Fibrosis.

    PubMed

    Yuen, Darren A; Huang, Yi-Wei; Liu, Guang-Ying; Patel, Sajedabanu; Fang, Fei; Zhou, Joyce; Thai, Kerri; Sidiqi, Ahmad; Szeto, Stephen G; Chan, Lauren; Lu, Mingliang; He, Xiaolin; John, Rohan; Gilbert, Richard E; Scholey, James W; Robinson, Lisa A

    2016-09-01

    Fibrosis and inflammation are closely intertwined injury pathways present in nearly all forms of CKD for which few safe and effective therapies exist. Slit glycoproteins signaling through Roundabout (Robo) receptors have been described to have anti-inflammatory effects through regulation of leukocyte cytoskeletal organization. Notably, cytoskeletal reorganization is also required for fibroblast responses to TGF-β Here, we examined whether Slit2 also controls TGF-β-induced renal fibrosis. In cultured renal fibroblasts, which we found to express Slit2 and Robo-1, the bioactive N-terminal fragment of Slit2 inhibited TGF-β-induced collagen synthesis, actin cytoskeletal reorganization, and Smad2/3 transcriptional activity, but the inactive C-terminal fragment of Slit2 did not. In mouse models of postischemic renal fibrosis and obstructive uropathy, treatment with N-terminal Slit2 before or after injury inhibited the development of renal fibrosis and preserved renal function, whereas the C-terminal Slit2 had no effect. Our data suggest that administration of recombinant Slit2 may be a new treatment strategy to arrest chronic injury progression after ischemic and obstructive renal insults by not only attenuating inflammation but also, directly inhibiting renal fibrosis.

  20. Slit2 involvement in glioma cell migration is mediated by Robo1 receptor.

    PubMed

    Mertsch, Sonja; Schmitz, Nicole; Jeibmann, Astrid; Geng, Jian-Guo; Paulus, Werner; Senner, Volker

    2008-03-01

    Slit and Robo proteins are evolutionarily conserved molecules whose interaction underlies axon guidance and neuronal precursor cell migration. During development secreted Slit proteins mediate chemorepulsive signals on cells expressing Robo receptors. Because similar molecular mechanisms may be utilized in glioma cell invasion and neuroblast migration, we studied the expression of Slit2 and its transmembrane receptor Robo1 as well as their functional role in migration in glioma cells. qRT-PCR and immunohistochemistry of human specimens revealed that Slit2 was distinctly expressed by non-neoplastic neurons, but at only very low levels in fibrillary astrocytoma and glioblastoma. Robo1 also was mainly restricted to neurons in the normal brain, whereas astrocytic tumor cells in situ as well as glioblastoma cell lines overexpressed Robo1 at mRNA and protein levels. Recombinant human Slit2 in a concentration of 0.45 nM was repulsive for glioma cell lines in a modified Boyden chamber assay. RNAi-mediated knockdown of Robo1 in glioma cell lines neutralized the repulsive effect of Slit2, demonstrating that Robo1 served as the major Slit2 receptor. Our findings suggest that a chemorepulsive effect mediated by interaction of Slit2 and Robo1 participates in glioma cell guidance in the brain.

  1. The axonal repellent Slit2 inhibits pericyte migration: potential implications in angiogenesis.

    PubMed

    Guijarro-Muñoz, I; Cuesta, A M; Alvarez-Cienfuegos, A; Geng, J G; Alvarez-Vallina, L; Sanz, L

    2012-02-15

    The Slit family of secreted proteins acts through the Roundabout (Robo) receptors to repel axonal migration during central nervous system development. Emerging evidence shows that Slit/Robo interactions also play a role in angiogenesis. The effect of Robo signaling on endothelial cells has been shown to be context-dependent. However, the role of Slit/Robo in pericytes has been largely unexplored. The aim of this study was to determine the effect of Slit2 on primary human pericytes and to address the underlying mechanisms, including the receptors potentially implicated. We demonstrate that both Robo1 and Robo4 are expressed by human pericytes. In the presence of their ligand Slit2, spontaneous and PDGF-induced migration of pericytes was impaired. This antimigratory activity of Slit-2 correlated with the inhibition of actin-based protrusive structures. Interestingly, human pericyte interaction with immobilized Slit2 was inhibited in the presence of anti-Robo1 and anti-Robo4 blocking antibodies, suggesting the implication of both receptors. These results add new insights into the role of Slit proteins during the angiogenic process that relies on the directional migration not only of endothelial cells but also of pericytes.

  2. Suppression of Slit2/Robo1 mediated HUVEC migration by Robo4.

    PubMed

    Enomoto, Satoshi; Mitsui, Kenichi; Kawamura, Takeshi; Iwanari, Hiroko; Daigo, Kenji; Horiuchi, Keiko; Minami, Takashi; Kodama, Tatsuhiko; Hamakubo, Takao

    2016-01-22

    Slit proteins and their receptors, the Roundabout (Robo) family, are known to have a pivotal role in the vascular system. Slit2/Robo1 regulates the migration of human umbilical vein endothelial cells (HUVECs) and tumor-associated endothelial cells. Robo4, the endothelial-specific Robo, is also considered to be involved in vascular cell migration. However, the Slit/Robo signaling pathway is still unclear. Using a Boyden chamber assay, we found that Slit2 induces the migration of HUVECs under a Robo4 knockdown condition. This effect disappeared in Robo1 knockdown cells. The co-existence of the N-terminal extracellular portion of Robo1 blocked the Slit2-evoked migration of HUVECs, while that of Robo4 caused no effect. These results show that the Slit2 signal is transduced through Robo1, while the negative regulation of Robo4 is an intracellular event. Targeted proteomics using an anti-Robo1 monoclonal antibody identified CdGAP, an adhesion-localized Rac1-and Cdc42-specific GTPase activating protein, as a candidate for Slit2/Robo1 signaling. Robo1 and CdGAP were co-immunoprecipitated from CHO cells co-transfected with Robo1 and CdGAP genes. These results suggest that Slit2/Robo1 binding exerts an effect on cell migration, which is negatively regulated by Robo4, and Robo1 may function by interacting with CdGAP in HUVECs.

  3. Slit2 prevents neutrophil recruitment and renal ischemia-reperfusion injury.

    PubMed

    Chaturvedi, Swasti; Yuen, Darren A; Bajwa, Amandeep; Huang, Yi-Wei; Sokollik, Christiane; Huang, Liping; Lam, Grace Y; Tole, Soumitra; Liu, Guang-Ying; Pan, Jerry; Chan, Lauren; Sokolskyy, Yaro; Puthia, Manoj; Godaly, Gabriela; John, Rohan; Wang, Changsen; Lee, Warren L; Brumell, John H; Okusa, Mark D; Robinson, Lisa A

    2013-07-01

    Neutrophils recruited to the postischemic kidney contribute to the pathogenesis of ischemia-reperfusion injury (IRI), which is the most common cause of renal failure among hospitalized patients. The Slit family of secreted proteins inhibits chemotaxis of leukocytes by preventing activation of Rho-family GTPases, suggesting that members of this family might modulate the recruitment of neutrophils and the resulting IRI. Here, in static and microfluidic shear assays, Slit2 inhibited multiple steps required for the infiltration of neutrophils into tissue. Specifically, Slit2 blocked the capture and firm adhesion of human neutrophils to inflamed vascular endothelial barriers as well as their subsequent transmigration. To examine whether these observations were relevant to renal IRI, we administered Slit2 to mice before bilateral clamping of the renal pedicles. Assessed at 18 hours after reperfusion, Slit2 significantly inhibited renal tubular necrosis, neutrophil and macrophage infiltration, and rise in plasma creatinine. In vitro, Slit2 did not impair the protective functions of neutrophils, including phagocytosis and superoxide production, and did not inhibit neutrophils from killing the extracellular pathogen Staphylococcus aureus. In vivo, administration of Slit2 did not attenuate neutrophil recruitment or bacterial clearance in mice with ascending Escherichia coli urinary tract infections and did not increase the bacterial load in the livers of mice infected with the intracellular pathogen Listeria monocytogenes. Collectively, these results suggest that Slit2 may hold promise as a strategy to combat renal IRI without compromising the protective innate immune response.

  4. The optical slit sensor as a standard sensor for spacecraft attitude determination

    NASA Technical Reports Server (NTRS)

    Wertz, J.

    1975-01-01

    The basic concept of an optical slit sensor as a standard altitude sensor is considered for any missions using a spinning spacecraft or where rotating sensors or mirrors could be used. Information available from a single sensor or from two sensors is analyzed. A standard slit sensor package is compared with the altitude package flown on the first synchronous meteorological satellite.

  5. Taking a bite: endocytosis in the maintenance of the slit diaphragm.

    PubMed

    Sampogna, Rosemary V; Al-Awqati, Qais

    2012-12-01

    In the kidney, the slit diaphragm joins adjacent podocytes, forming an epithelial barrier that filters plasma into the urinary space, yet retains blood cells and proteins within the circulation. In this issue of the JCI, Soda et al. have identified clathrin-mediated endocytosis as a central mechanism by which the function and structural integrity of the slit diaphragm are maintained.

  6. Slit-Surface Electrospinning: A Novel Process Developed for High-Throughput Fabrication of Core-Sheath Fibers

    PubMed Central

    Yan, Xuri; Marini, John; Mulligan, Robert; Deleault, Abby; Sharma, Upma; Brenner, Michael P.; Rutledge, Gregory C.; Freyman, Toby; Pham, Quynh P.

    2015-01-01

    In this work, we report on the development of slit-surface electrospinning – a process that co-localizes two solutions along a slit surface to spontaneously emit multiple core-sheath cone-jets at rates of up to 1 L/h. To the best of our knowledge, this is the first time that production of electrospun core-sheath fibers has been scaled to this magnitude. Fibers produced in this study were defect-free (i.e. non-beaded) and core-sheath geometry was visually confirmed under scanning electron microscopy. The versatility of our system was demonstrated by fabrication of (1) fibers encapsulating a drug, (2) bicomponent fibers, (3) hollow fibers, and (4) fibers from a polymer that is not normally electrospinnable. Additionally, we demonstrate control of the process by modulating parameters such as flow rate, solution viscosity, and fixture design. The technological achievements demonstrated in this work significantly advance core-sheath electrospinning towards commercial and manufacturing viability. PMID:25938411

  7. Scan mirrors relay for high resolution laser scanning systems

    NASA Astrophysics Data System (ADS)

    Kessler, David

    2014-09-01

    Two dimensional beam deflection is often required in medical laser scanning systems such as OCT or confocal microscopy. Commonly two linear galvo mirrors are used for performance in terms of their large apertures and scan angles. The galvo mirrors are placed at the vicinity of entrance pupil of the scan lens with a "displacement distance" separating them. This distance limits the scan fields and/or reduces the effective aperture of the scan lens. Another option is to use a beam or pupil relay, and image one galvo mirror onto the other. However, beam (or pupil) relays are notoriously complicated, expensive and can add significant aberrations. This paper discusses a simple, all reflective, diffraction limited, color corrected, beam relay, capable of large scan angles and large deflecting mirrors. The design is based on a unique combination of an Offner configuration with a Schmidt aspheric corrector. The design is highly corrected up to large scan mirrors and large scan angles down to milliwaves of aberrations. It allows significantly larger scan field and or scan lenses with higher numerical aperture as compared with scanners using galvos separated by the displacement distance. While this relay is of exceptionally high performance, it has one element located where the beam is focused which may present a problem for high power lasers. Thus modifications of the above design are introduced where the beam is focused in mid air thus making it usable for high power systems such including laser marking and fabrication systems.

  8. Production of Slit2 LRR domains in mammalian cells for structural studies and the structure of human Slit2 domain 3.

    PubMed

    Morlot, Cecile; Hemrika, Wieger; Romijn, Roland A; Gros, Piet; Cusack, Stephen; McCarthy, Andrew A

    2007-09-01

    Slit2 and Roundabout 1 (Robo1) provide a key ligand-receptor interaction for the navigation of commissural neurons during the development of the central nervous system. Slit2 is a large multidomain protein containing an unusual domain organization of four tandem leucine-rich repeat (LRR) domains at its N-terminus. These domains are well known to mediate protein-protein interactions; indeed, the Robo1-binding region has been mapped to the concave face of the second LRR domain. It has also been shown that the fourth LRR domain may mediate Slit dimerization and that both the first and second domains can bind heparin. Thus, while roles have been ascribed for three of the LRR domains, there is still no known role for the third domain. Each of the four LRR domains from human Slit2 have now been successfully expressed in milligram quantities using expression in mammalian cells. Here, the crystallization of the second and third LRR domains and the structure of the third LRR domain are presented. This is the first structure of an LRR domain from human Slit2, which has an extra repeat compared with the Drosophila homologue. It is proposed that a highly conserved patch of surface residues on the concave face may mediate any protein-protein interactions involving this LRR domain, a result that will be useful in guiding further studies on Slit2.

  9. Slit2 promotes tumor growth and invasion in chemically induced skin carcinogenesis.

    PubMed

    Qi, Cuiling; Lan, Haimei; Ye, Jie; Li, Weidong; Wei, Ping; Yang, Yang; Guo, Simei; Lan, Tian; Li, Jiangchao; Zhang, Qianqian; He, Xiaodong; Wang, Lijing

    2014-07-01

    Slit, a neuronal guidance cue, binds to Roundabout (Robo) receptors to modulate neuronal, leukocytic, and endothelial migration. Slit has been reported to have an important effect on tumor growth and metastasis. In the current study, we evaluated the role of Slit2 in skin tumor growth and invasion in mice using a two-step chemical carcinogenesis protocol. We found that Slit2 expression correlated with the loss of basement membrane in the samples of human skin squamous cell carcinoma at different stages of disease progression. Slit2-Tg mice developed significantly more skin tumors than wild-type mice. Furthermore, the skin tumors that occurred in Slit2-Tg mice were significantly larger than those in the wild-type mice 10 weeks after 7,12-dimethylbenz[a]anthracene initiation until the end of the experiment. We also found that pathological development of the wild-type mice was delayed compared with that of Slit2-Tg mice. To further investigate the mechanism of increasing tumors in Slit2-Tg mice, we analyzed the expression of 5-bromo-2'-deoxyuridine (BrdU) in mouse skin lesions and found that the number of BrdU-positive cells and microvessel density in skin lesions were significantly higher in Slit2-Tg mice than in wild-type mice. Histological staining of PAS and type IV collagen and the colocalization of Slit2 and type IV collagen demonstrated varying degrees of loss of the basement membrane in the skin lesions from Slit2-Tg mice that were at the stage of carcinoma in situ. However, the basement membrane was well defined in the wild-type mice. In addition, MMP2, but not MMP9, was upregulated in the skin tissue of Slit2-Tg mice. Interruption of Slit2-Robo1 signaling by the antibody R5 significantly repressed the invasive capability of the squamous cell carcinoma cell line A431. Taken together, our findings reveal that Slit2 promotes DMBA/TPA-induced skin tumorigenesis by increasing cell proliferation, microvessel density, and invasive behavior of cutaneous squamous

  10. DEVELOPMENT OF A HYDROSTATIC JOURNAL BEARING WITH SLIT-STEP COMPENSATION

    SciTech Connect

    Hale, L C; Donaldson, R R; Castro, C; Chung, C A; Hopkins, D J

    2006-07-28

    This paper describes the mathematical modeling and initial testing of an oil-hydrostatic bearing that derives compensation from both a central radial slit where fluid enters and stepped clearances near each end. Bearings using either a radial slit or stepped clearances for compensation were well studied over forty years ago by Donaldson. These bearings have smooth bores uninterrupted with multiple recesses around the circumference. The present slit-step bearing achieves the best of both types with somewhat higher hydrostatic stiffness than the slit bearing and fluid shear drag lower than the step bearing. This is apparent in TABLE 1, which compares calculated values of initial (i.e., centered) hydrostatic stiffness for each type. The slit-step bearing is one of several types being studied at Lawrence Livermore National Laboratory for possible use on the Precision Optical Grinder and Lathe (POGAL).

  11. Super-transmission from a finite subwavelength arrangement of slits in a metal film.

    PubMed

    Chen, Shuwen; Jin, Shilong; Gordon, Reuven

    2014-06-01

    A theory is presented for the transmission of transverse magnetic waves through a finite number of subwavelength slits in metal film. While a single slit achieves the single channel limit on resonance, multiple slits show super-transmission exceeding the single channel limit. The phenomenon of super-transmission is revealed as a result of cross-coupling of modes and confirmed by simulations. The influence of finite permittivity in the IR and microwave regime is included by perturbative corrections to the theory. The theory agrees quantitatively with past experiments and finite-difference time-domain simulations. By considering two or more modes in the slit region, our theory provides an approach to the analysis of cross-coupling among slits, which allows for super-transmission and features of a Fano resonance.

  12. Double Photoionization of H2: Double Slit Interference?

    NASA Astrophysics Data System (ADS)

    Horner, Daniel; Miyabe, Shungo; Morales, Felipe; Martin, Fernando; Rescigno, Thomas; McCurdy, C. William

    2008-10-01

    Using the method of exterior complex scaling and the finite element discrete variable representation, we are able to compute accurate time-independent wave functions for the double photoionization of H2. Together with integral amplitude methods, these accurate wave function solutions allow us to calculate converged differential cross sections. We present the double differential cross section at photon energies between 130 eV and 240 eV. At these energies, recent experiments have observed angular distributions that were interpreted as double slit interference of the electrons ejected from near the two nuclei. With our theoretical methods, we are able to examine this question further and will offer an alternate interpretation based on the coherent mixture of parallel and perpendicular polarization in the circularly polarized light.

  13. REDUCEME: Long-slit spectroscopic data reduction and analysis

    NASA Astrophysics Data System (ADS)

    Cardiel, N.; Gorgas, J.; Pedraz, S.; Cenarro, J.; Alonso, O.; Gil de Paz, A.; García-Dabó, E.; Sánchez-Blázquez, P.; Mármol-Queraltó, E.; Toloba, E.

    2015-08-01

    The astronomical data reduction package REDUCEME reduces and analyzes long-slit spectroscopic data. The package uses the unformatted FORTRAN raw data format, so requires FITS files be transformed to REDUCEME format; the reverse operation (from REDUCEME to FITS format) is also available. The package is a set of programs written in FORTRAN 77 and includes shell scripts (using the C shell syntax) to perform routine tasks; it can be extended by the inclusion of external programs. REDUCEME uses PGPLOT (ascl:1103.002) for line plots and images, and a subset of subroutines, called BUTTON, enables the user to communicate interactively with the image display employing graphic buttons. One advantage of using REDUCEME is that for each image an associated error image can also be processed throughout the reduction process, allowing for a careful control of the error propagation.

  14. Study of spiral flow generated through an annular slit

    NASA Astrophysics Data System (ADS)

    Kim, Tae Hun; Matsuo, Shigeru; Setoguchi, Toshiaki; Kim, Heuy-Dong

    2005-06-01

    The effect of pressurized air inlets in the reservoir upstream of the annular slit on characteristics of the axial and tangential velocity components is investigated numerically, and the mechanism of occurrence of spiral nozzle flow is clarified. In simulations, Unified Platform for Aerospace Computational Simulation (UPACS) is used. The governing equations under consideration are the unsteady compressible Navier - Stokes. A second-order finite volume scheme with MUSCL (Roe scheme) is used to discretize the spatial derivatives, and a second order-central difference scheme for the viscous terms, and a MFGS (Matrix Free Gauss Seidel) is employed for time integration. Spalart-Allmaras model was used as a turbulence model. The results obtained are compared with velocity distributions in the experiment measured by the two-component fiber optic laser Doppler velocimeter system. The existence of discrete pressurized air inlets that leads to the occurrence of asymmetrical characteristics is a very important factor for the formation of spiral flow.

  15. 3-D Printed Slit Nozzles for Fourier Transform Microwave Spectroscopy

    NASA Astrophysics Data System (ADS)

    Dewberry, Chris; Mackenzie, Becca; Green, Susan; Leopold, Ken

    2015-06-01

    3-D printing is a new technology whose applications are only beginning to be explored. In this report, we describe the application of 3-D printing to the facile design and construction of supersonic nozzles. The efficacy of a variety of designs is assessed by examining rotational spectra OCS and Ar-OCS using a Fourier transform microwave spectrometer with tandem cavity and chirped-pulse capabilities. This work focuses primarily on the use of slit nozzles but other designs have been tested as well. New nozzles can be created for 0.50 or less each, and the ease and low cost should facilitate the optimization of nozzle performance (e.g., jet temperature or cluster size distribution) for the needs of any particular experiment.

  16. Chemical "Double Slits": dynamical interference of photodissociation pathways in water

    PubMed

    Dixon; Hwang; Yang; Harich; Lin; Yang

    1999-08-20

    Photodissociation of water at a wavelength of 121.6 nanometers has been investigated by using the H-atom Rydberg tagging technique. A striking even-odd intensity oscillation was observed in the OH(X) product rotational distribution. Model calculations attribute this oscillation to an unusual dynamical interference brought about by two dissociation pathways that pass through dissimilar conical intersections of potential energy surfaces, but result in the same products. The interference pattern and the OH product rotational distribution are sensitive to the positions and energies of the conical intersections, one with the atoms collinear as H-OH and the other as H-HO. An accurate simulation of the observations would provide a detailed test of global H(2)O potential energy surfaces for the three (&Xtilde;/A/&Btilde;) contributing states. The interference observed from the two conical intersection pathways provides a chemical analog of Young's well-known double-slit experiment.

  17. Micro digital sun sensor with linear detector.

    PubMed

    Fan, Qiao-Yun; Peng, Jia-Wen; Gao, Xin-Yang

    2016-07-01

    In this paper, the design of a novel micro digital sun sensor is described. It relies on V-shaped slit and linear array CCD to measure sun-ray angle against two axes. A highly integrated microprogram control unit) is used to make a very simple and compact system. V-shaped slit can simplify algorithm and achieve a wider field of view. Error compensation and accurate calibration are employed to improve accuracy. Adaptive threshold and adjustable expose time further improve reliability. Experiments and flight validation show that the FOV (Field of View) of the sun sensor is ±65°  ×   ± 65° and the accuracy is 0.1° in the whole FOV. It can work reliably at an update rate of 25 Hz, while the consumption is only 200 mW. This sun sensor is proved to have a good prospect in micro/nanosatellites.

  18. Micro digital sun sensor with linear detector

    NASA Astrophysics Data System (ADS)

    Fan, Qiao-yun; Peng, Jia-wen; Gao, Xin-yang

    2016-07-01

    In this paper, the design of a novel micro digital sun sensor is described. It relies on V-shaped slit and linear array CCD to measure sun-ray angle against two axes. A highly integrated microprogram control unit) is used to make a very simple and compact system. V-shaped slit can simplify algorithm and achieve a wider field of view. Error compensation and accurate calibration are employed to improve accuracy. Adaptive threshold and adjustable expose time further improve reliability. Experiments and flight validation show that the FOV (Field of View) of the sun sensor is ±65° × ± 65° and the accuracy is 0.1° in the whole FOV. It can work reliably at an update rate of 25 Hz, while the consumption is only 200 mW. This sun sensor is proved to have a good prospect in micro/nanosatellites.

  19. Micro digital sun sensor with linear detector.

    PubMed

    Fan, Qiao-Yun; Peng, Jia-Wen; Gao, Xin-Yang

    2016-07-01

    In this paper, the design of a novel micro digital sun sensor is described. It relies on V-shaped slit and linear array CCD to measure sun-ray angle against two axes. A highly integrated microprogram control unit) is used to make a very simple and compact system. V-shaped slit can simplify algorithm and achieve a wider field of view. Error compensation and accurate calibration are employed to improve accuracy. Adaptive threshold and adjustable expose time further improve reliability. Experiments and flight validation show that the FOV (Field of View) of the sun sensor is ±65°  ×   ± 65° and the accuracy is 0.1° in the whole FOV. It can work reliably at an update rate of 25 Hz, while the consumption is only 200 mW. This sun sensor is proved to have a good prospect in micro/nanosatellites. PMID:27475588

  20. Dimensional reduction of duplex DNA under confinement to nanofluidic slits.

    PubMed

    Vargas-Lara, Fernando; Stavis, Samuel M; Strychalski, Elizabeth A; Nablo, Brian J; Geist, Jon; Starr, Francis W; Douglas, Jack F

    2015-11-14

    There has been much interest in the dimensional properties of double-stranded DNA (dsDNA) confined to nanoscale environments as a problem of fundamental importance in both biological and technological fields. This has led to a series of measurements by fluorescence microscopy of single dsDNA molecules under confinement to nanofluidic slits. Despite the efforts expended on such experiments and the corresponding theory and simulations of confined polymers, a consistent description of changes of the radius of gyration of dsDNA under strong confinement has not yet emerged. Here, we perform molecular dynamics (MD) simulations to identify relevant factors that might account for this inconsistency. Our simulations indicate a significant amplification of excluded volume interactions under confinement at the nanoscale due to the reduction of the effective dimensionality of the system. Thus, any factor influencing the excluded volume interaction of dsDNA, such as ionic strength, solution chemistry, and even fluorescent labels, can greatly influence the dsDNA size under strong confinement. These factors, which are normally less important in bulk solutions of dsDNA at moderate ionic strengths because of the relative weakness of the excluded volume interaction, must therefore be under tight control to achieve reproducible measurements of dsDNA under conditions of dimensional reduction. By simulating semi-flexible polymers over a range of parameter values relevant to the experimental systems and exploiting past theoretical treatments of the dimensional variation of swelling exponents and prefactors, we have developed a novel predictive relationship for the in-plane radius of gyration of long semi-flexible polymers under slit-like confinement. Importantly, these analytic expressions allow us to estimate the properties of dsDNA for the experimentally and biologically relevant range of contour lengths that is not currently accessible by state-of-the-art MD simulations.

  1. Two-slit experiment: quantum and classical probabilities

    NASA Astrophysics Data System (ADS)

    Khrennikov, Andrei

    2015-06-01

    Inter-relation between quantum and classical probability models is one of the most fundamental problems of quantum foundations. Nowadays this problem also plays an important role in quantum technologies, in quantum cryptography and the theory of quantum random generators. In this letter, we compare the viewpoint of Richard Feynman that the behavior of quantum particles cannot be described by classical probability theory with the viewpoint that quantum-classical inter-relation is more complicated (cf, in particular, with the tomographic model of quantum mechanics developed in detail by Vladimir Man'ko). As a basic example, we consider the two-slit experiment, which played a crucial role in quantum foundational debates at the beginning of quantum mechanics (QM). In particular, its analysis led Niels Bohr to the formulation of the principle of complementarity. First, we demonstrate that in complete accordance with Feynman's viewpoint, the probabilities for the two-slit experiment have the non-Kolmogorovian structure, since they violate one of basic laws of classical probability theory, the law of total probability (the heart of the Bayesian analysis). However, then we show that these probabilities can be embedded in a natural way into the classical (Kolmogorov, 1933) probability model. To do this, one has to take into account the randomness of selection of different experimental contexts, the joint consideration of which led Feynman to a conclusion about the non-classicality of quantum probability. We compare this embedding of non-Kolmogorovian quantum probabilities into the Kolmogorov model with well-known embeddings of non-Euclidean geometries into Euclidean space (e.g., the Poincaré disk model for the Lobachvesky plane).

  2. Solid particle impingement erosion characteristics of cylindrical surfaces, pre-existing holes and slits

    NASA Technical Reports Server (NTRS)

    Rao, P. V.; Buckley, D. H.

    1983-01-01

    The erosion characteristics of aluminum cylinders sand-blasted with both spherical and angular erodent particles were studied and compared with results from previously studied flat surfaces. The cylindrical results are discussed with respect to impact conditions. The relationship between erosion rate and pit morphology (width, depth, and width to depth ratio) is established. The aspects of (1) erosion rate versus time curves on cylindrical surfaces; (2) long-term exposures; and (3) erosion rate versus time curves with spherical and angular particles are presented. The erosion morphology and characteristics of aluminum surfaces with pre-existing circular cylindrical and conical holes of different sizes were examined using weight loss measurements, scanning electron microscopy, a profilometer, and a depth gage. The morphological features (radial and concentric rings) are discussed with reference to flat surfaces, and the erosion features with spherical microglass beads. The similarities and differences of erosion and morphological features are highlighted. The erosion versus time curves of various shapes of holes are discussed and are compared with those of a flat surface. The erosion process at slits is considered.

  3. Frequent alterations of SLIT2-ROBO1-CDC42 signalling pathway in breast cancer: clinicopathological correlation.

    PubMed

    Bhattacharya, Rittwika; Mukherjee, Nupur; Dasgupta, Hemantika; Islam, Md Saimul; Alam, Neyaz; Roy, Anup; Das, Priyobrata; Roychoudhury, Susanta; Panda, Chinmay Kumar

    2016-09-01

    The aim of the study was to understand the role of SLIT2-ROBO1/2-CDC42 signalling pathways in development of breast cancer (BC). Primary BC samples (n = 150), comprising of almost equal proportion of four subtypes were tested for molecular alterations of SLIT2, ROBO1, ROBO2 and CDC42, the key regulator genes of this pathway. Deletion and methylation frequencies of the candidate genes were seen in the following order: deletion, SLIT2 (38.6%) > ROBO1 (30%) > ROBO2 (7.3%); methylation, SLIT2 (63.3%) > ROBO1 (26.6%) >ROBO2 (9.3%). Majority (80%, 120/150) of the tumours showed alterations (deletion/methylation) in at least one of the candidate genes. Overall, alterations of the candidate genes were as follows: SLIT2, 75.3% (101/150); ROBO1, 45.3% (68/150); ROBO2, 15.3% (23/150). Significantly, higher alteration of SLIT2 locus was observed in triple negative breast cancer (TNBC) over HER2 subtype (P = 0.0014). Similar trend is also seen in overall alterations of SLIT2 and/or ROBO1, in TNBC than HER2 subtype (P = 0.0012); of SLIT2 and/or ROBO2 in TNBC than luminal A (P = 0.014) and HER2 subtype (P = 0.048). Immunohistochemical analysis of SLIT2, ROBO1/2 showed reduced expression, concordant with their molecular alterations. Also, high expression of total CDC42 (49/52; 94.2%) and reduced expression of phospho Serine-71 CDC42 (41/52; 78.8%) was observed. Coalterations of SLIT2 and/or ROBO1, SLIT2 and/or ROBO2 had significant association with reduced expression of phospho Serine-71 CDC42 (P = 0.0012-0.0038). Alterations of SLIT2 and/or ROBO1, reduced expression of phospho Serine-71 CDC42 predicted poor survival of BC patients. Results indicate the importance of SLIT2-ROBO1-CDC42 signalling pathway in predicting tumour progression.

  4. `Mathematical' Cracks Versus Artificial Slits: Implications in the Determination of Fracture Toughness

    NASA Astrophysics Data System (ADS)

    Markides, Ch. F.; Kourkoulis, S. K.

    2016-03-01

    An analytic solution is introduced for the stress field developed in a circular finite disc weakened by a central slit of arbitrary ratio of its edges and slightly rounded corners. The disc is loaded by radial pressure applied along two finite arcs of its periphery, anti-symmetric with respect to the disc's center. The motive of the study is to consider the stress field in a disc with a mechanically machined slit (finite distance between the two lips) in juxtaposition to the respective field in the same disc with a `mathematical' crack (zero distance between lips), which is the configuration adopted in case the fracture toughness of brittle materials is determined according to the standardized cracked Brazilian-disc test. The solution is obtained using Muskhelishvili's complex potentials' technique adopting a suitable conformal mapping function found, also, in Savin's milestone book. For the task to be accomplished, an auxiliary problem is first solved, namely, the infinite plate with a rectangular slit (in case the resultant force on the slit is zero and also the stresses and rotations at infinity are zero), by mapping conformally the area outside the slit onto the mathematical plane with a unit hole. The formulae obtained for the complex potentials permit the analytic exploration of the stress field along some loci of crucial practical importance. The influence of the slit's width on the local stress amplification and also on the stress concentration around the crown of the slit is quantitatively described. In addition, the role of the load-application mode (compression along the slit's longitudinal symmetry axis and tension normal to it) is explored. Results indicate that the two configurations are not equivalent in terms of the stress concentration factor. In addition, depending on the combination of the slit's width and the load-application mode, the point where the normal stress along the slit's boundary is maximized `oscillates' between the central point of

  5. Frequent alterations of SLIT2-ROBO1-CDC42 signalling pathway in breast cancer: clinicopathological correlation.

    PubMed

    Bhattacharya, Rittwika; Mukherjee, Nupur; Dasgupta, Hemantika; Islam, Md Saimul; Alam, Neyaz; Roy, Anup; Das, Priyobrata; Roychoudhury, Susanta; Panda, Chinmay Kumar

    2016-09-01

    The aim of the study was to understand the role of SLIT2-ROBO1/2-CDC42 signalling pathways in development of breast cancer (BC). Primary BC samples (n = 150), comprising of almost equal proportion of four subtypes were tested for molecular alterations of SLIT2, ROBO1, ROBO2 and CDC42, the key regulator genes of this pathway. Deletion and methylation frequencies of the candidate genes were seen in the following order: deletion, SLIT2 (38.6%) > ROBO1 (30%) > ROBO2 (7.3%); methylation, SLIT2 (63.3%) > ROBO1 (26.6%) >ROBO2 (9.3%). Majority (80%, 120/150) of the tumours showed alterations (deletion/methylation) in at least one of the candidate genes. Overall, alterations of the candidate genes were as follows: SLIT2, 75.3% (101/150); ROBO1, 45.3% (68/150); ROBO2, 15.3% (23/150). Significantly, higher alteration of SLIT2 locus was observed in triple negative breast cancer (TNBC) over HER2 subtype (P = 0.0014). Similar trend is also seen in overall alterations of SLIT2 and/or ROBO1, in TNBC than HER2 subtype (P = 0.0012); of SLIT2 and/or ROBO2 in TNBC than luminal A (P = 0.014) and HER2 subtype (P = 0.048). Immunohistochemical analysis of SLIT2, ROBO1/2 showed reduced expression, concordant with their molecular alterations. Also, high expression of total CDC42 (49/52; 94.2%) and reduced expression of phospho Serine-71 CDC42 (41/52; 78.8%) was observed. Coalterations of SLIT2 and/or ROBO1, SLIT2 and/or ROBO2 had significant association with reduced expression of phospho Serine-71 CDC42 (P = 0.0012-0.0038). Alterations of SLIT2 and/or ROBO1, reduced expression of phospho Serine-71 CDC42 predicted poor survival of BC patients. Results indicate the importance of SLIT2-ROBO1-CDC42 signalling pathway in predicting tumour progression. PMID:27659325

  6. Slit/Robo1 signaling regulates neural tube development by balancing neuroepithelial cell proliferation and differentiation

    SciTech Connect

    Wang, Guang; Li, Yan; Wang, Xiao-yu; Han, Zhe; Chuai, Manli; Wang, Li-jing; Ho Lee, Kenneth Ka; Geng, Jian-guo; Yang, Xuesong

    2013-05-01

    Formation of the neural tube is the morphological hallmark for development of the embryonic central nervous system (CNS). Therefore, neural tube development is a crucial step in the neurulation process. Slit/Robo signaling was initially identified as a chemo-repellent that regulated axon growth cone elongation, but its role in controlling neural tube development is currently unknown. To address this issue, we investigated Slit/Robo1 signaling in the development of chick neCollege of Life Sciences Biocentre, University of Dundee, Dundee DD1 5EH, UKural tube and transgenic mice over-expressing Slit2. We disrupted Slit/Robo1 signaling by injecting R5 monoclonal antibodies into HH10 neural tubes to block the Robo1 receptor. This inhibited the normal development of the ventral body curvature and caused the spinal cord to curl up into a S-shape. Next, Slit/Robo1 signaling on one half-side of the chick embryo neural tube was disturbed by electroporation in ovo. We found that the morphology of the neural tube was dramatically abnormal after we interfered with Slit/Robo1 signaling. Furthermore, we established that silencing Robo1 inhibited cell proliferation while over-expressing Robo1 enhanced cell proliferation. We also investigated the effects of altering Slit/Robo1 expression on Sonic Hedgehog (Shh) and Pax7 expression in the developing neural tube. We demonstrated that over-expressing Robo1 down-regulated Shh expression in the ventral neural tube and resulted in the production of fewer HNK-1{sup +} migrating neural crest cells (NCCs). In addition, Robo1 over-expression enhanced Pax7 expression in the dorsal neural tube and increased the number of Slug{sup +} pre-migratory NCCs. Conversely, silencing Robo1 expression resulted in an enhanced Shh expression and more HNK-1{sup +} migrating NCCs but reduced Pax7 expression and fewer Slug{sup +} pre-migratory NCCs were observed. In conclusion, we propose that Slit/Robo1 signaling is involved in regulating neural tube

  7. Influence of polymer architecture and polymer-wall interaction on the adsorption of polymers into a slit-pore.

    PubMed

    Chen, Zhong; Escobedo, Fernando A

    2004-02-01

    The effects of molecular topology and polymer-surface interaction on the properties of isolated polymer chains trapped in a slit were investigated using off-lattice Monte Carlo simulations. Various methods were implemented to allow efficient simulation of molecular structure, confinement force, and free energy for a chain interacting with such "sticky" surfaces. The simulations were performed in the canonical ensemble, and the free energy was sampled via virtual slit-separation moves. Six different chain architectures were studied: linear, star-branched, dendritic, cyclic, two-node (i.e., containing two tetrafunctional intramolecular crosslinks), and six-node molecules. The first three topologies entail increasing degrees of branching, and the last three topologies entail increasing degrees of intramolecular bonding. The confinement force, monomer density profile, and conformational properties for all these systems were compared (for identical molecular weight N) and analyzed as a function of adsorption strength. The compensation point where the wall attraction counterbalances the polymer-slit exclusion effects was the focus of our study. It was found that the attractive energy at the compensation point, epsilon(c), is a weak increasing function of the chain length for excluded-volume chains. The value of epsilon(c) differs significantly for different topologies, and smaller values are associated with better-adsorbing molecules. Due to their globular shape and numerous chain ends, branched molecules (e.g., stars and dendrimers) experience a relatively small entropic penalty for adsorption at low adsorption force and moderate confinement. However, as the adsorption force increases, the more flexible linear chains reach the compensation point at a weaker attractive energy because of the ease with which monomers can be packed near the walls. In moderate to weak confinement, molecules with intramolecular cross-links, such as cyclic, two-node, and six-node molecules

  8. Influence of polymer architecture and polymer-wall interaction on the adsorption of polymers into a slit-pore

    NASA Astrophysics Data System (ADS)

    Chen, Zhong; Escobedo, Fernando A.

    2004-02-01

    The effects of molecular topology and polymer-surface interaction on the properties of isolated polymer chains trapped in a slit were investigated using off-lattice Monte Carlo simulations. Various methods were implemented to allow efficient simulation of molecular structure, confinement force, and free energy for a chain interacting with such “sticky” surfaces. The simulations were performed in the canonical ensemble, and the free energy was sampled via virtual slit-separation moves. Six different chain architectures were studied: linear, star-branched, dendritic, cyclic, two-node (i.e., containing two tetrafunctional intramolecular crosslinks), and six-node molecules. The first three topologies entail increasing degrees of branching, and the last three topologies entail increasing degrees of intramolecular bonding. The confinement force, monomer density profile, and conformational properties for all these systems were compared (for identical molecular weight N) and analyzed as a function of adsorption strength. The compensation point where the wall attraction counterbalances the polymer-slit exclusion effects was the focus of our study. It was found that the attractive energy at the compensation point, ɛc, is a weak increasing function of the chain length for excluded-volume chains. The value of ɛc differs significantly for different topologies, and smaller values are associated with better-adsorbing molecules. Due to their globular shape and numerous chain ends, branched molecules (e.g., stars and dendrimers) experience a relatively small entropic penalty for adsorption at low adsorption force and moderate confinement. However, as the adsorption force increases, the more flexible linear chains reach the compensation point at a weaker attractive energy because of the ease with which monomers can be packed near the walls. In moderate to weak confinement, molecules with intramolecular cross-links, such as cyclic, two-node, and six-node molecules, always

  9. Head CT scan

    MedlinePlus

    Brain CT; Cranial CT; CT scan - skull; CT scan - head; CT scan - orbits; CT scan - sinuses; Computed tomography - cranial; CAT scan - brain ... conditions: Birth (congenital) defect of the head or brain Brain infection Brain tumor Buildup of fluid inside ...

  10. Analysis of electroosmotic flow of power-law fluids in a slit microchannel.

    PubMed

    Zhao, Cunlu; Zholkovskij, Emilijk; Masliyah, Jacob H; Yang, Chun

    2008-10-15

    Electroosmotic flow of power-law fluids in a slit channel is analyzed. The governing equations including the linearized Poisson-Boltzmann equation, the Cauchy momentum equation, and the continuity equation are solved to seek analytical expressions for the shear stress, dynamic viscosity, and velocity distribution. Specifically, exact solutions of the velocity distributions are explicitly found for several special values of the flow behavior index. Furthermore, with the implementation of an approximate scheme for the hyperbolic cosine function, approximate solutions of the velocity distributions are obtained. In addition, a generalized Smoluchowski velocity is introduced by taking into account contributions due to the finite thickness of the electric double layer and the flow behavior index of power-law fluids. Calculations are performed to examine the effects of kappaH, flow behavior index, double layer thickness, and applied electric field on the shear stress, dynamic viscosity, velocity distribution, and average velocity/flow rate of the electroosmotic flow of power-law fluids. PMID:18656891

  11. Slit2 regulates the dispersal of oligodendrocyte precursor cells via Fyn/RhoA signaling.

    PubMed

    Liu, Xiujie; Lu, Yan; Zhang, Yong; Li, Yuanyuan; Zhou, Jiazhen; Yuan, Yimin; Gao, Xiaofei; Su, Zhida; He, Cheng

    2012-05-18

    Oligodendrocyte precursor cells (OPCs) are a unique type of glia that are responsible for the myelination of the central nervous system. OPC migration is important for myelin formation during central nervous system development and repair. However, the precise extracellular and intracellular mechanisms that regulate OPC migration remain elusive. Slits were reported to regulate neurodevelopmental processes such as migration, adhesion, axon guidance, and elongation through binding to roundabout receptors (Robos). However, the potential roles of Slits/Robos in oligodendrocytes remain unknown. In this study, Slit2 was found to be involved in regulating the dispersal of OPCs through the association between Robo1 and Fyn. Initially, we examined the expression of Robos in OPCs both in vitro and in vivo. Subsequently, the Boyden chamber assay showed that Slit2 could inhibit OPC migration. RoboN, a specific inhibitor of Robos, could significantly attenuate this effect. The effects were confirmed through the explant migration assay. Furthermore, treating OPCs with Slit2 protein deactivated Fyn and increased the level of activated RhoA-GTP. Finally, Fyn was found to form complexes with Robo1, but this association was decreased after Slit2 stimulation. Thus, we demonstrate for the first time that Slit2 regulates the dispersal of oligodendrocyte precursor cells through Fyn and RhoA signaling.

  12. Expression of Slit2 and Robo1 after traumatic lesions of the rat spinal cord.

    PubMed

    Liu, Jin-Bo; Jiang, Yu-Qin; Gong, Ai-Hua; Zhang, Zhi-Jian; Jiang, Qian; Chu, Xiang-Ping

    2011-01-01

    We have used semi-quantitative RT-PCR, Western blot, and immunofluorescence imaging approaches to detect the expression levels of Slit2 and its receptor Robo1 in the rat spinal cord after traumatic lesions. Our results revealed that both the mRNA and protein levels of Slit2 were up-regulated in the injured spinal cord. The Slit2 expression level was increased at day 7 until day 14, and then returned to normal level at day 21 after injury. A double-immunolabelling study showed that Slit2 and neurofilament (NF) proteins were both localized in neurons of spinal corda cinerea. Slit2 immunopositivity was detected in neuronal plasma membranes but not in the axonal fibers. In contrast, the immunolabelling of Robo1 in the normal spinal cord was at a low level, mostly in the neurons of spinal corda cinerea, and remained unchanged at all time points following spinal cord injury (SCI). The regulation levels of Slit2 and Robo1 after traumatic lesions in the rat spinal cord are different. Our results indicate that Slit2-Robo1 might not be involved in the inhibitory environment after SCI.

  13. Slit2-Robo4 receptor responses inhibit ANDV directed permeability of human lung microvascular endothelial cells.

    PubMed

    Gorbunova, Elena E; Gavrilovskaya, Irina N; Mackow, Erich R

    2013-08-01

    Hantaviruses nonlytically infect human endothelial cells (ECs) and cause edematous and hemorrhagic diseases. Andes virus (ANDV) causes hantavirus pulmonary syndrome (HPS), and Hantaan virus (HTNV) causes hemorrhagic fever with renal syndrome (HFRS). Hantaviruses enhance vascular endothelial growth factor directed EC permeability resulting in the disassembly of inter-endothelial cell adherens junctions (AJs). Recent studies demonstrate that Slit2 binding to Robo1/Robo4 receptors on ECs has opposing effects on AJ disassembly and vascular fluid barrier functions. Here we demonstrate that Slit2 inhibits ANDV and HTNV induced permeability and AJ disassembly of pulmonary microvascular ECs (PMECs) by interactions with Robo4. In contrast, Slit2 had no effect on the permeability of ANDV infected human umbilical vein ECs (HUVECs). Analysis of Robo1/Robo4 expression determined that PMECs express Robo4, but not Robo1, while HUVECs expressed both Robo4 and Robo1 receptors. SiRNA knockdown of Robo4 in PMECs prevented Slit2 inhibition of ANDV induced permeability demonstrating that Robo4 receptors determine PMEC responsiveness to Slit2. Collectively, this data demonstrates a selective role for Slit2/Robo4 responses within PMECs that inhibits ANDV induced permeability and AJ disassembly. These findings suggest Slit2s utility as a potential HPS therapeutic that stabilizes the pulmonary endothelium and antagonizes ANDV induced pulmonary edema.

  14. Semiconductor fabrication techniques for producing an ultra-flat reflective slit

    NASA Astrophysics Data System (ADS)

    Vandervelde, Thomas E.; Cabral, Michael J.; Wilson, John; Skrutskie, Michael

    2006-06-01

    The most difficult aspects in manufacturing a reflective slit substrate are achieving a precisely fabricated slit surrounded by an optically flat surface. A commonly used technique is to polish a metal substrate that has a slit cut by electric discharge machine (EDM) methods. This process can produce 'optically flat' surfaces; however, the EDM can produce a slit with edge roughness on the order of 10 microns and a RMS field roughness of ~1 micron. Here, we present a departure from these traditional methods and employ the advantages inherent in integrated circuit fabrication. By starting with a silicon wafer, we begin with a nearly atomically flat surface. In addition, the fabrication tools and methodologies employed are traditionally used for high precision applications: this allows for the placement and definition of the slit with high accuracy. If greater accuracy in slit definition is required, additional tools, such as a focused ion beam, are used to define the slit edge down to tens of nanometers. The deposition of gold, after that of a suitable bonding layer, in an ultra-high vacuum chamber creates a final surface without the need of polishing. Typical results yield a surface RMS-roughness of approximately 2nm. Most of the techniques and tools required for this process are commonly available at research universities and the cost to manufacture said mirrors is a small fraction of the purchase price of the traditional ones.

  15. Ultrathin multi-slit metamaterial as excellent sound absorber: Influence of micro-structure

    NASA Astrophysics Data System (ADS)

    Ren, S. W.; Meng, H.; Xin, F. X.; Lu, T. J.

    2016-01-01

    An ultrathin (subwavelength) hierarchy multi-slit metamaterial with simultaneous negative effective density and negative compressibility is proposed to absorb sound over a wide frequency range. Different from conventional acoustic metamaterials having only negative real parts of acoustic parameters, the imaginary parts of effective density and compressibility are both negative for the proposed metamaterial, which result in superior viscous and thermal dissipation of sound energy. By combining the slit theory of sound absorption with the double porosity theory for porous media, a theoretical model is developed to investigate the sound absorption performance of the metamaterial. To verify the model, a finite element model is established to calculate the effective density, compressibility, and sound absorption of the metamaterial. It is theoretically and numerically confirmed that, upon introducing micro-slits into the meso-slits matrix, the multi-slit metamaterial possesses indeed negative imaginary parts of effective density and compressibility. The influence of micro-slits on the acoustical performance of the metamaterial is analyzed in the context of its specific surface area and static flow resistivity. This work shows great potential of multi-slit metamaterials in noise control applications that require both small volume and small weight of sound-absorbing materials.

  16. Potential anti-angiogenic role of Slit2 in corneal neovascularization.

    PubMed

    Han, Xi; Zhang, Ming-Chang

    2010-06-01

    Slits are large secreted proteins critical for axon guidance and neuronal precursor cell migration in nervous system. Evidence suggests that classical neuronal guidance cues also regulate vascular development. Our objective was to investigate whether neuronal guidance cue Slit2 and Roundabout (Robo) receptors are involved in corneal neovascularization (NV). Corneal NV model in rats was induced by implantation of agarose-coated gelfoam pellets containing basic fibroblast growth factor (bFGF) into corneal stroma. Differential expression of Slit2 and Robo1-4 between normal and neovascularized cornea was detected by real-time RT-PCR and visualized by immunohistochemistry and in situ hybridization. Primary human umbilical vein endothelial cells (HUVECs) were harvested and their expression of Robo1-4 was detected by RT-PCR. Recombinant human Slit2 protein was prepared and the effect of it on the migration of vascular endothelial cells was examined using cell migration assay. Agarose-coated gelfoam pellets were able to induce well-localized and reproducible corneal NV model. A significant down-regulation of Slit2 and a strong up-regulation of Robo1 and Robo4 were seen in neovascularized cornea when compared with normal cornea (P < 0.05). Slit2, Robo1 and Robo4 were throughout the epithelium in normal cornea and markedly weak or absent in epithelium in neovascularized cornea, with Robo1 and Robo4 being prominent in vascular endothelial cells invading the stroma. Primary HUVECs were confirmed to express both Robo1 and Robo4 receptors and their migration was inhibited by Slit2 (P < 0.05). This is the first study to assess the association between Slit2 and corneal NV. Our findings suggest that the interaction of Slit2 with Robo1 and Robo4 receptors plays an essential role in inhibiting pathological neovascular processes of the cornea and may represent a new therapeutic target for corneal NV.

  17. Mutations of the SLIT2-ROBO2 pathway genes SLIT2 and SRGAP1 confer risk for congenital anomalies of the kidney and urinary tract.

    PubMed

    Hwang, Daw-Yang; Kohl, Stefan; Fan, Xueping; Vivante, Asaf; Chan, Stefanie; Dworschak, Gabriel C; Schulz, Julian; van Eerde, Albertien M; Hilger, Alina C; Gee, Heon Yung; Pennimpede, Tracie; Herrmann, Bernhard G; van de Hoek, Glenn; Renkema, Kirsten Y; Schell, Christoph; Huber, Tobias B; Reutter, Heiko M; Soliman, Neveen A; Stajic, Natasa; Bogdanovic, Radovan; Kehinde, Elijah O; Lifton, Richard P; Tasic, Velibor; Lu, Weining; Hildebrandt, Friedhelm

    2015-08-01

    Congenital anomalies of the kidney and urinary tract (CAKUT) account for 40-50% of chronic kidney disease that manifests in the first two decades of life. Thus far, 31 monogenic causes of isolated CAKUT have been described, explaining ~12% of cases. To identify additional CAKUT-causing genes, we performed whole-exome sequencing followed by a genetic burden analysis in 26 genetically unsolved families with CAKUT. We identified two heterozygous mutations in SRGAP1 in 2 unrelated families. SRGAP1 is a small GTPase-activating protein in the SLIT2-ROBO2 signaling pathway, which is essential for development of the metanephric kidney. We then examined the pathway-derived candidate gene SLIT2 for mutations in cohort of 749 individuals with CAKUT and we identified 3 unrelated individuals with heterozygous mutations. The clinical phenotypes of individuals with mutations in SLIT2 or SRGAP1 were cystic dysplastic kidneys, unilateral renal agenesis, and duplicated collecting system. We show that SRGAP1 is expressed in early mouse nephrogenic mesenchyme and that it is coexpressed with ROBO2 in SIX2-positive nephron progenitor cells of the cap mesenchyme in developing rat kidney. We demonstrate that the newly identified mutations in SRGAP1 lead to an augmented inhibition of RAC1 in cultured human embryonic kidney cells and that the SLIT2 mutations compromise the ability of the SLIT2 ligand to inhibit cell migration. Thus, we report on two novel candidate genes for causing monogenic isolated CAKUT in humans.

  18. Mutations of the SLIT2-ROBO2 pathway genes SLIT2 and SRGAP1 Confer Risk for Congenital Anomalies of the Kidney and Urinary Tract

    PubMed Central

    Hwang, Daw-Yang; Kohl, Stefan; Fan, Xueping; Vivante, Asaf; Chan, Stefanie; Dworschak, Gabriel C; Schulz, Julian; van Eerde, Albertien M; Hilger, Alina C; Gee, Heon Yung; Pennimpede, Tracie; Herrmann, Bernhard G; van de Hoek, Glenn; Renkema, Kirsten Y; Schell, Christoph; Huber, Tobias B; Reutter, Heiko M; Soliman, Neveen A; Stajic, Natasa; Bogdanovic, Radovan; Kehinde, Elijah O; Lifton, Richard P; Tasic, Velibor; Lu, Weining; Hildebrandt, Friedhelm

    2015-01-01

    Congenital anomalies of the kidney and urinary tract (CAKUT) account for 40–50% of chronic kidney disease that manifests in the first two decades of life. Thus far, 31 monogenic causes of isolated CAKUT have been described, explaining ~12% of cases. To identify additional CAKUT-causing genes, we performed whole exome sequencing followed by a genetic burden analysis in 26 genetically unsolved families with CAKUT. We identified two heterozygous mutations in SRGAP1 in 2 unrelated families. SRGAP1 is a small GTPase activating protein in the SLIT2-ROBO2 signaling pathway, which is essential for development of the metanephric kidney. We then examined the pathway-derived candidate gene SLIT2 for mutations in cohort of 749 individuals with CAKUT and we identified 3 unrelated individuals with heterozygous mutations. The clinical phenotypes of individuals with mutations in SLIT2 or SRGAP1 were cystic dysplastic kidneys, unilateral renal agenesis, and duplicated collecting system. We show that SRGAP1 is expressed in early mouse nephrogenic mesenchyme and that it is coexpressed with ROBO2 in SIX2-positive nephron progenitor cells of the cap mesenchyme in developing rat kidney. We demonstrate that the newly identified mutations in SRGAP1 lead to an augmented inhibition of RAC1 in cultured human embryonic kidney cells and that the SLIT2 mutations compromise the ability of the SLIT2 ligand to inhibit cell migration. Thus, we report on two novel candidate genes for causing monogenic isolated CAKUT in humans. PMID:26026792

  19. Mutations of the SLIT2-ROBO2 pathway genes SLIT2 and SRGAP1 confer risk for congenital anomalies of the kidney and urinary tract.

    PubMed

    Hwang, Daw-Yang; Kohl, Stefan; Fan, Xueping; Vivante, Asaf; Chan, Stefanie; Dworschak, Gabriel C; Schulz, Julian; van Eerde, Albertien M; Hilger, Alina C; Gee, Heon Yung; Pennimpede, Tracie; Herrmann, Bernhard G; van de Hoek, Glenn; Renkema, Kirsten Y; Schell, Christoph; Huber, Tobias B; Reutter, Heiko M; Soliman, Neveen A; Stajic, Natasa; Bogdanovic, Radovan; Kehinde, Elijah O; Lifton, Richard P; Tasic, Velibor; Lu, Weining; Hildebrandt, Friedhelm

    2015-08-01

    Congenital anomalies of the kidney and urinary tract (CAKUT) account for 40-50% of chronic kidney disease that manifests in the first two decades of life. Thus far, 31 monogenic causes of isolated CAKUT have been described, explaining ~12% of cases. To identify additional CAKUT-causing genes, we performed whole-exome sequencing followed by a genetic burden analysis in 26 genetically unsolved families with CAKUT. We identified two heterozygous mutations in SRGAP1 in 2 unrelated families. SRGAP1 is a small GTPase-activating protein in the SLIT2-ROBO2 signaling pathway, which is essential for development of the metanephric kidney. We then examined the pathway-derived candidate gene SLIT2 for mutations in cohort of 749 individuals with CAKUT and we identified 3 unrelated individuals with heterozygous mutations. The clinical phenotypes of individuals with mutations in SLIT2 or SRGAP1 were cystic dysplastic kidneys, unilateral renal agenesis, and duplicated collecting system. We show that SRGAP1 is expressed in early mouse nephrogenic mesenchyme and that it is coexpressed with ROBO2 in SIX2-positive nephron progenitor cells of the cap mesenchyme in developing rat kidney. We demonstrate that the newly identified mutations in SRGAP1 lead to an augmented inhibition of RAC1 in cultured human embryonic kidney cells and that the SLIT2 mutations compromise the ability of the SLIT2 ligand to inhibit cell migration. Thus, we report on two novel candidate genes for causing monogenic isolated CAKUT in humans. PMID:26026792

  20. Single-Slit Diffraction: Transitioning from Geometric Optics to the Fraunhofer Regime

    NASA Astrophysics Data System (ADS)

    Panuski, Christopher L.; Mungan, Carl E.

    2016-09-01

    Suppose a red laser beam (of wavelength λ equal to 0.660 μm) is expanded using an optical telescope into a collimated, approximately plane wave that is 5.68 mm in diameter. Pass that beam through a tall rectangular slit whose width a is gradually reduced from 3.30 to 0.100 mm. Look at its image on a screen located at a distance L from the slit equal to 0.656 m. As the slit is narrowed, you predict that the width of the pattern will: (A) smoothly increase, (B) smoothly decrease, (C)increase and then decrease, or (D) decrease and then increase.

  1. Performance of a simplified slit spatial filter for large laser systems.

    PubMed

    Xiong, Han; Yuan, Xiao; Zhang, Xiang; Zou, Kuaisheng

    2014-09-01

    A new-type slit spatial filter system with three lenses was proposed, in which the focal spot was turned into focal line by adding cylindrical lenses to increase focal area and then lower the focal intensity. Its performances on image relay, aperture matching and spatial filtering are comprehended by detailed theoretical calculations and numerical simulation. According to transmission spatial filter in national ignition facility, we present a replaceable slit spatial filter, which can reduce the overall length of laser system, improve the beam quality and suppress or even avoid the pinhole (slit) closure in the spatial filter. PMID:25321597

  2. Young's experiment with a double slit of sub-wavelength dimensions.

    PubMed

    Lee, Kanghee; Lim, Jongseok; Ahn, Jaewook

    2013-08-12

    We report that the interference pattern of Young's double-slit experiment changes as a function of polarization in the sub-wavelength diffraction regime. Experiments carried out with terahertz time-domain spectroscopy reveal that diffracted waves from sub-wavelength-scale slits exhibit either positive or negative phase shift with respect to Gouy phase depending on the polarization. Theoretical explanation based on the induction of electric current and magnetic dipole in the vicinity of the slits shows an excellent agreement with the experimental results.

  3. Narrow band imaging and long slit spectroscopy of UGC 5101

    NASA Technical Reports Server (NTRS)

    Stanga, R. M.; Mannucci, F.; Rodriguezespinosa, J. M.

    1993-01-01

    UGC 5101 (z = 0.04; D is approximately equal to 240 Mpc) is one of the so called Ultraluminous IRAS sources. Two important properties of the members of this group are their L(sub IR) is greater than or equal to 10(exp 12) solar luminosity, and their space density in the universe up to z is less than 0.1 is equal or even larger than the space density of the quasars. Further noteworthy features of the Ultraluminous IRAS sources are their being morphologically peculiar and the fact that they all seem to host active nuclei in their center. We have observed UGC 5101 in an effort to study the interplay between the gas ionized by the central active nucleus and that gas ionized by other processes which may hold important clues to the understanding of the entire picture of this object. In particular these other ionizing processes could well be massive stars formed recently after the galactic encounter and shocks possibly also related to the galaxy collision. The data that we discuss were obtained between Dec. 1989 and Jan. 1992 with the WHT 4.2 m telescope using the two-arm spectrograph ISIS. Several spectral frames were obtained at three different position angles: PA 84--along the tail of the galaxy; PA 32--along the dust lane; and PA 110. The blue spectra are centered on the H beta line, while the red spectra are centered on the H alpha line. In the configuration we used for the long slit spectra, the spectral scale was 0.74 A per pixel, and the spatial scale was .37 arcsec per pixel; we also observed the H alpha region with a spectral scale of .37 A per pixel, at position angle 84. The narrow band images were obtained at the auxiliary port of ISIS, with a scale of .2 arcsec per pixel, and were centered at the H alpha wavelength, and on the adjacent continuum. The H alpha images and the spectra support the following model. UGC 5101 hosts an active nucleus; the NLR extends up to about 1.5 kpc and shows a complex velocity field, superimposed on the rotation curve of the

  4. Nanofocusing enhancement in a tapered slit by using a dielectric micro isosceles triangle prism and tuning the entrance aperture

    NASA Astrophysics Data System (ADS)

    Kuang, Dengfeng; Ouyang, Sheng; Du, Zhongxun

    2012-07-01

    We present a combined configuration consisting of a dielectric micro isosceles triangular prism and a metallic tapered slit for enhanced nanofocusing. The dielectric micro isosceles triangular prism collects the incident light first and then the tapered slit guides the beam to form naofocusing with higher intensity at the exit aperture of the tapered slit, which overcomes the limit of the extremely small entrance aperture diaphragm of the slit. With the help of the dielectric micro isosceles triangular prism, the intensity of the nanofocused electric field at the exit aperture of the tapered slit can be increased more than 4 folds.

  5. Linear Accelerators

    SciTech Connect

    Sidorin, Anatoly

    2010-01-05

    In linear accelerators the particles are accelerated by either electrostatic fields or oscillating Radio Frequency (RF) fields. Accordingly the linear accelerators are divided in three large groups: electrostatic, induction and RF accelerators. Overview of the different types of accelerators is given. Stability of longitudinal and transverse motion in the RF linear accelerators is briefly discussed. The methods of beam focusing in linacs are described.

  6. Double-slit interference effect in electron emission from H2+ exposed to x-ray radiation

    NASA Astrophysics Data System (ADS)

    Guan, Xiaoxu; Secor, Ethan B.; Bartschat, Klaus; Schneider, Barry I.

    2012-04-01

    We consider the photoionization of the hydrogen molecular ion exposed to x-ray radiation for photon energies up to 500 eV in the fixed-nuclei approximation. The temporal development of the system is described by a fully ab initio time-dependent grid-based approach in prolate spheroidal coordinates. At sufficently high photon energies, the angular distributions of the electron ejected from the two-center diatomic target resemble the classical double-slit-like interference pattern more closely when the molecular axis and the linear laser polarization direction are perpendicular to each other than in the parallel geometry. Both the preferable emission modes and the confinement effect (in the parallel geometry) of the photoelectron also map out in the time evolution of the wave packets. The validity of a simple plane-wave model is analyzed by comparing its predictions with those from our accurate ab initio calculations.

  7. Fast slit-beam extraction and chopping for neutron generator

    NASA Astrophysics Data System (ADS)

    Kalvas, T.; Hahto, S. K.; Gicquel, F.; King, M.; Vainionpää, J. H.; Reijonen, J.; Leung, K. N.; Miller, T. G.

    2006-03-01

    High-intensity fast white neutron pulses are needed for pulsed fast neutron transmission spectroscopy (PFNTS). A compact tritium-tritium fusion reaction neutron generator with an integrated ion beam chopping system has been designed, simulated, and tested for PFNTS. The design consists of a toroidal plasma chamber with 20 extraction slits, concentric cylindrical electrodes, chopper plates, and a central titanium-coated beam target. The total ion beam current is 1A. The beam chopping is done at 30keV energy with a parallel-plate deflector integrated with an Einzel lens. Beam pulses with 5ns width can be achieved with a 15ns rise/fall time ±1500V sweep on the chopper plates. The neutrons are produced at 120keV energy. A three-dimensional simulation code based on Vlasov iteration was developed for simulating the ion optics of this system. The results with this code were found to be consistent with other simulation codes. So far we have measured 50ns ion beam pulses from the system.

  8. Fast slit-beam extraction and chopping for neutron generator

    SciTech Connect

    Kalvas, T.; Hahto, S.K.; Gicquel, F.; King, M.; Vainionpaeae, J.H.; Reijonen, J.; Leung, K.N.; Miller, T.G.

    2006-03-15

    High-intensity fast white neutron pulses are needed for pulsed fast neutron transmission spectroscopy (PFNTS). A compact tritium-tritium fusion reaction neutron generator with an integrated ion beam chopping system has been designed, simulated, and tested for PFNTS. The design consists of a toroidal plasma chamber with 20 extraction slits, concentric cylindrical electrodes, chopper plates, and a central titanium-coated beam target. The total ion beam current is 1 A. The beam chopping is done at 30 keV energy with a parallel-plate deflector integrated with an Einzel lens. Beam pulses with 5 ns width can be achieved with a 15 ns rise/fall time {+-}1500 V sweep on the chopper plates. The neutrons are produced at 120 keV energy. A three-dimensional simulation code based on Vlasov iteration was developed for simulating the ion optics of this system. The results with this code were found to be consistent with other simulation codes. So far we have measured 50 ns ion beam pulses from the system.

  9. From concave to convex: capillary bridges in slit pore geometry.

    PubMed

    Broesch, David J; Frechette, Joelle

    2012-11-01

    We investigate the morphological evolution of nonaxisymmetric capillary bridges in slit-pore geometry as the height of the pore and aspect ratio of the bridge are varied. The liquid bridges are formed between two hydrophobic surfaces patterned with hydrophilic strips. The aspect ratio of the capillary bridges (length/width) is varied from 2.5 to 120 by changing the separation between the surfaces, the width of the strips, or the fluid volume. As the bridge height is increased, the aspect ratio decreases and we observe a large increase in the mean curvature of the bridge. More specifically, the following counterintuitive result is observed: the mean curvature of the bridges changes sign and goes from negative (concave bridge) to positive (convex bridge) when the height is increased at constant volume. These experimental observations are in quantitative agreement with Surface Evolver simulations. Scaling shows a collapse of the data indicating that this transition in the sign of the Laplace pressure is universal for capillary bridges with high aspect ratios. Finally, we show that the morphology diagrams obtained from our 3D analysis are considerably different from those expected from a 2D analysis.

  10. Early regimes of water capillary flow in slit silica nanochannels.

    PubMed

    Oyarzua, Elton; Walther, Jens H; Mejía, Andrés; Zambrano, Harvey A

    2015-06-14

    Molecular dynamics simulations are conducted to investigate the initial stages of spontaneous imbibition of water in slit silica nanochannels surrounded by air. An analysis is performed for the effects of nanoscopic confinement, initial conditions of liquid uptake and air pressurization on the dynamics of capillary filling. The results indicate that the nanoscale imbibition process is divided into three main flow regimes: an initial regime where the capillary force is balanced only by the inertial drag and characterized by a constant velocity and a plug flow profile. In this regime, the meniscus formation process plays a central role in the imbibition rate. Thereafter, a transitional regime takes place, in which, the force balance has significant contributions from both inertia and viscous friction. Subsequently, a regime wherein viscous forces dominate the capillary force balance is attained. Flow velocity profiles identify the passage from an inviscid flow to a developing Poiseuille flow. Gas density profiles ahead of the capillary front indicate a transient accumulation of air on the advancing meniscus. Furthermore, slower capillary filling rates computed for higher air pressures reveal a significant retarding effect of the gas displaced by the advancing meniscus.

  11. From concave to convex: capillary bridges in slit pore geometry.

    PubMed

    Broesch, David J; Frechette, Joelle

    2012-11-01

    We investigate the morphological evolution of nonaxisymmetric capillary bridges in slit-pore geometry as the height of the pore and aspect ratio of the bridge are varied. The liquid bridges are formed between two hydrophobic surfaces patterned with hydrophilic strips. The aspect ratio of the capillary bridges (length/width) is varied from 2.5 to 120 by changing the separation between the surfaces, the width of the strips, or the fluid volume. As the bridge height is increased, the aspect ratio decreases and we observe a large increase in the mean curvature of the bridge. More specifically, the following counterintuitive result is observed: the mean curvature of the bridges changes sign and goes from negative (concave bridge) to positive (convex bridge) when the height is increased at constant volume. These experimental observations are in quantitative agreement with Surface Evolver simulations. Scaling shows a collapse of the data indicating that this transition in the sign of the Laplace pressure is universal for capillary bridges with high aspect ratios. Finally, we show that the morphology diagrams obtained from our 3D analysis are considerably different from those expected from a 2D analysis. PMID:23061424

  12. Fabrication and Visualization of Capillary Bridges in Slit Pore Geometry

    PubMed Central

    Broesch, David J.; Frechette, Joelle

    2014-01-01

    A procedure for creating and imaging capillary bridges in slit-pore geometry is presented. High aspect ratio hydrophobic pillars are fabricated and functionalized to render their top surfaces hydrophilic. The combination of a physical feature (the pillar) with a chemical boundary (the hydrophilic film on the top of the pillar) provides both a physical and chemical heterogeneity that pins the triple contact line, a necessary feature to create stable long but narrow capillary bridges. The substrates with the pillars are attached to glass slides and secured into custom holders. The holders are then mounted onto four axis microstages and positioned such that the pillars are parallel and facing each other. The capillary bridges are formed by introducing a fluid in the gap between the two substrates once the separation between the facing pillars has been reduced to a few hundred micrometers. The custom microstage is then employed to vary the height of the capillary bridge. A CCD camera is positioned to image either the length or the width of the capillary bridge to characterize the morphology of the fluid interface. Pillars with widths down to 250 µm and lengths up to 70 mm were fabricated with this method, leading to capillary bridges with aspect ratios (length/width) of over 1001. PMID:24457446

  13. The slit ventricle syndrome: advances based on technology and understanding.

    PubMed

    Rekate, Harold L

    2004-01-01

    Despite many articles on slit ventricle syndrome (SVS) over the last 25 years, accepted terminology regarding the definition of this condition is lacking. Any shunted individual with a severe headache disorder in the context of ventricles that are normal or smaller than normal can be said to suffer from SVS, even though there are at least five forms of the condition. Logical management of SVS requires an understanding of the specific pathogenesis of the problem in individual patients, whether based on monitoring of intracranial pressure (ICP) or observation at the time of shunt failure or symptoms. Overdrainage syndromes, whether intermittent proximal obstruction or low pressure states, are best managed with valve upgrades and the addition of devices that retard siphoning. Increased ICP without ventriculomegaly at the time of shunt failure is best managed by shunting devices that access the cortical subarachnoid space such as lumboperitoneal shunts or shunts involving the cisterna magna. Cranial expansion operations and subtemporal decompression should be limited to patients with craniofacial syndromes.

  14. Full controlling of Fano resonances in metal-slit superlattice

    PubMed Central

    Deng, Zi-Lan; Yogesh, Natesan; Chen, Xiao-Dong; Chen, Wen-Jie; Dong, Jian-Wen; Ouyang, Zhengbiao; Wang, Guo Ping

    2015-01-01

    Controlling of the lineshape of Fano resonance attracts much attention recently due to its wide capabilities for lasing, biosensing, slow-light applications and so on. However, the controllable Fano resonance always requires stringent alignment of complex symmetry-breaking structures and thus the manipulation could only be performed with limited degrees of freedom and narrow tuning range. Furthermore, there is no report so far on independent controlling of both the bright and dark modes in a single structure. Here, we semi-analytically show that the spectral position and linewidth of both the bright and dark modes can be tuned independently and/or simultaneously in a simple and symmetric metal-slit superlattice, and thus allowing for a free and continuous controlling of the lineshape of both the single and multiple Fano resonances. The independent controlling scheme is applicable for an extremely large electromagnetic spectrum range from optical to microwave frequencies, which is demonstrated by the numerical simulations with real metal and a microwave experiment. Our findings may provide convenient and flexible strategies for future tunable electromagnetic devices. PMID:26680258

  15. Slit disk for modified faraday cup diagnostic for determining power density of electron and ion beams

    DOEpatents

    Teruya, Alan T.; Elmer; John W.; Palmer, Todd A.

    2011-03-08

    A diagnostic system for characterization of an electron beam or an ion beam includes an electrical conducting disk of refractory material having a circumference, a center, and a Faraday cup assembly positioned to receive the electron beam or ion beam. At least one slit in the disk provides diagnostic characterization of the electron beam or ion beam. The at least one slit is located between the circumference and the center of the disk and includes a radial portion that is in radial alignment with the center and a portion that deviates from radial alignment with the center. The electron beam or ion beam is directed onto the disk and translated to the at least one slit wherein the electron beam or ion beam enters the at least one slit for providing diagnostic characterization of the electron beam or ion beam.

  16. Transition from a spectrum filter to a polarizer in a metallic nano-slit array

    PubMed Central

    Zhou, Jing; Guo, L. Jay

    2014-01-01

    The transition from a spectrum filter (resonant transmission) to a polarizer (broadband transmission) for TM polarized light is observed in a metallic nano-slit array as period is decreased. A theoretical model is developed and shows that the spectrum filter behavior is caused by the coupled slit/grating resonance. With decreasing period, the slit resonance is decoupled from the grating resonance, which then dominates the transmission spectrum and broadens the transmission peak. With further reducing period, the slit resonance diminishes and the peak spectrum transforms to a broadband transmission. This effect is the basis for the operation of wire grid polarizers. The transition is explained by the change of the impedance to the incoming wave. PMID:24402443

  17. Demonstrations Using a Fabry-Perot. I. Multiple-Slit Interference

    ERIC Educational Resources Information Center

    Roychoudhuri, Chandrasekhar

    1975-01-01

    Describes a demonstration technique for showing multiple-slit interference patterns with the use of a Fabry-Perot etalon and a laser beam. A simple derivation of the analytical expression for such fringes is presented. (Author/CP)

  18. How diffraction limits ultrasonic screening in phononic plate composed of a periodic array of resonant slits

    NASA Astrophysics Data System (ADS)

    Elayouch, Aliyasin; Addouche, Mahmoud; Lasaygues, Philippe; Achaoui, Younes; Ouisse, Morvan; Khelif, Abdelkrim

    2016-05-01

    We explore experimentally the role played by diffraction in the phenomenon of acoustic shielding provided by a plate that is periodically perforated with subwavelength slits and immersed in water. We carried out ultrasonic transmission measurements for all directions of propagation in order to check the omnidirectionality of acoustic shielding. While a single slit acts as a Fabry-Perot resonator in the frequency range of interest, the coupling between adjacent slits provides an attenuation frequency band centered around the resonant frequency that is mostly independent of the angle of incidence. Beyond the incident angle of 45 degrees, however, we observe the appearance of scattered radiation that limits the attenuation of ultrasound. This spurious scattering is shown to arise from diffraction by the grating of slits. xml:lang="fr"

  19. Diffraction imaging characteristics of slit for ultra-short laser pulse

    NASA Astrophysics Data System (ADS)

    Yu, Xiang-yang; Wu, Kun-xi; Lu, Long-zhao

    2015-08-01

    We propose a simple and concise mathematical method based on the Fraunhofer approximation to analyze the imaging characteristics of slit for broadband light sources. Taking Gaussian-shaped ultra-short laser pulse for example, we investigated the diffraction imaging characteristics of ultra-short light sources through a single-slit and a double-slit. We deduced the mathematical expressions of the intensity distribution of far-field diffraction, and conducted numerical calculation and analysis. It turns out the pulse width of the ultra-short light source plays an important role in the diffraction imaging characteristics of slit. We also provide a quantitative criterion to measure the deviation in terms of far-field diffraction intensity distribution between broadband light source and the ideal monochromatic light source.

  20. Slit2 overexpression results in increased microvessel density and lesion size in mice with induced endometriosis.

    PubMed

    Guo, Sun-Wei; Zheng, Yu; Lu, Yuan; Liu, Xishi; Geng, Jian-Guo

    2013-03-01

    We recently reported that Slit/Roundabout (ROBO) 1 pathway may be a constituent biomarker for recurrence of endometriosis, likely through promoting angiogenesis. In this study, we sought to determine as whether Slit2 overexpression can facilitate angiogenesis, increase lesion size, and induce hyperalgesia in mice with induced endometriosis. We used 30 Slit2 transgenic (S) and 29 wild-type (W) mice and cross-transplanted endometrial fragments from S to W (group SW) and vice versa (group WS), and also within the S and W (groups SS and WW, respectively), into the peritoneal cavity, inducing endometriosis. We also performed a sham surgery within both S and W mice (groups Sm and Wm, respectively). The size of the ectopic implants, microvessel density (MVD) and immunoreactivity to ROBO1, and vascular endothelial cell growth factor (VEGF) in ectopic and eutopic endometrium, along with hotplate and tail-flick tests in all mice, were then evaluated. We found that the induction of endometriosis resulted in generalized hyperalgesia, which was unaffected by Slit2 overexpression. Slit2 overexpression did increase the lesion size significantly and correlated positively with the MVD in ectopic and eutopic endometrium. Slit2 expression levels appear to correlate with the MVD, but not with VEGF immunoreactivity, in ectopic endometrium. Consequently, we conclude that Slit2 may play an important role in angiogenesis in endometriosis. The increased angiogenesis, as measured by MVD, but not VEGF immunoreactivity, likely resulted in increased lesion size in induced endometriosis. Thus, SLIT2/ROBO1 pathway may be a potential therapeutic target for treating endometriosis.

  1. Myo9b is a key player in SLIT/ROBO-mediated lung tumor suppression

    PubMed Central

    Kong, Ruirui; Yi, Fengshuang; Wen, Pushuai; Liu, Jianghong; Chen, Xiaoping; Ren, Jinqi; Li, Xiaofei; Shang, Yulong; Nie, Yongzhan; Wu, Kaichun; Fan, Daiming; Zhu, Li; Feng, Wei; Wu, Jane Y.

    2015-01-01

    Emerging evidence indicates that the neuronal guidance molecule SLIT plays a role in tumor suppression, as SLIT-encoding genes are inactivated in several types of cancer, including lung cancer; however, it is not clear how SLIT functions in lung cancer. Here, our data show that SLIT inhibits cancer cell migration by activating RhoA and that myosin 9b (Myo9b) is a ROBO-interacting protein that suppresses RhoA activity in lung cancer cells. Structural analyses revealed that the RhoGAP domain of Myo9b contains a unique patch that specifically recognizes RhoA. We also determined that the ROBO intracellular domain interacts with the Myo9b RhoGAP domain and inhibits its activity; therefore, SLIT-dependent activation of RhoA is mediated by ROBO inhibition of Myo9b. In a murine model, compared with control lung cancer cells, SLIT-expressing cells had a decreased capacity for tumor formation and lung metastasis. Evaluation of human lung cancer and adjacent nontumor tissues revealed that Myo9b is upregulated in the cancer tissue. Moreover, elevated Myo9b expression was associated with lung cancer progression and poor prognosis. Together, our data identify Myo9b as a key player in lung cancer and as a ROBO-interacting protein in what is, to the best of our knowledge, a newly defined SLIT/ROBO/Myo9b/RhoA signaling pathway that restricts lung cancer progression and metastasis. Additionally, our work suggests that targeting the SLIT/ROBO/Myo9b/RhoA pathway has potential as a diagnostic and therapeutic strategy for lung cancer. PMID:26529257

  2. Revisiting the Young's double slit experiment for background-free nonlinear Raman spectroscopy and microscopy.

    PubMed

    Gachet, David; Brustlein, Sophie; Rigneault, Hervé

    2010-05-28

    In the Young's double slit experiment, the spatial shift of the interference pattern projected onto a screen is directly related to the phase difference between the fields diffracted by the two slits. We apply this property to fields emitted by nonlinear processes and thus demonstrate background-free coherent anti-Stokes Raman scattering microscopy near an axial interface between a resonant and a nonresonant medium. This method is relevant to remove the nonresonant background in other coherent resonant processes.

  3. Characterizing the phase profile of a vortex beam with angular-double-slit interference

    NASA Astrophysics Data System (ADS)

    Liu, Ruifeng; Long, Junling; Wang, Feiran; Wang, Yunlong; Zhang, Pei; Gao, Hong; Li, Fuli

    2013-12-01

    The diffracted intensity distribution of a Laguerre-Gaussian beam is studied with an angular-double-slit interferometer. We experimentally demonstrate that the spiral phase structure of a vortex beam can be clearly revealed in this interference geometry, and it gives us an efficient way to distinguish different orders of Laguerre-Gaussian beams. This angular-double-slit interferometer gives us a better understanding of the phase structure of a vortex beam and the interference phenomenon of vortex beams.

  4. A Secreted Slit2 Fragment Regulates Adipose Tissue Thermogenesis and Metabolic Function.

    PubMed

    Svensson, Katrin J; Long, Jonathan Z; Jedrychowski, Mark P; Cohen, Paul; Lo, James C; Serag, Sara; Kir, Serkan; Shinoda, Kosaku; Tartaglia, Julia A; Rao, Rajesh R; Chédotal, Alain; Kajimura, Shingo; Gygi, Steven P; Spiegelman, Bruce M

    2016-03-01

    Activation of brown and beige fat can reduce obesity and improve glucose homeostasis through nonshivering thermogenesis. Whether brown or beige fat also secretes paracrine or endocrine factors to promote and amplify adaptive thermogenesis is not fully explored. Here we identify Slit2, a 180 kDa member of the Slit extracellular protein family, as a PRDM16-regulated secreted factor from beige fat cells. In isolated cells and in mice, full-length Slit2 is cleaved to generate several smaller fragments, and we identify an active thermogenic moiety as the C-terminal fragment. This Slit2-C fragment of 50 kDa promotes adipose thermogenesis, augments energy expenditure, and improves glucose homeostasis in vivo. Mechanistically, Slit2 induces a robust activation of PKA signaling, which is required for its prothermogenic activity. Our findings establish a previously unknown peripheral role for Slit2 as a beige fat secreted factor that has therapeutic potential for the treatment of obesity and related metabolic disorders.

  5. Developmental guidance of embryonic corneal innervation: roles of Semaphorin3A and Slit2.

    PubMed

    Kubilus, James K; Linsenmayer, Thomas F

    2010-08-01

    The cornea is one of the most densely innervated structures of the body. In the developing chicken embryo, nerves from the ophthalmic trigeminal ganglion (OTG) innervate the cornea in a series of spatially and temporally regulated events. However, little is known concerning the signals that regulate these events. Here we have examined the involvement of the axon guidance molecules Semaphorin3A and Slit2, and their respective receptors, Neuropilin-1 and Robo2. Expression analyses of early corneas suggest an involvement of both Semaphorin3A and Slit2 in preventing nerves from entering the corneal stroma until the proper time (i.e., they serve as negative regulators), and analyses of their receptors support this conclusion. At later stages of development the expression of Semaphorin3A is again consistent with its serving as a negative regulator-this time for nerves entering the corneal epithelium. However, expression analyses of Robo2 at this stage raised the possibility that Slit2 had switched from a negative regulator to a positive regulator. In support of such a switch, functional analyses-by addition of recombinant Slit2 protein or immunoneutralization with a Slit2 antibody-showed that at an early stage Slit2 negatively regulates the outgrowth of nerves from the OTG, whereas at the later stage it positively regulated the growth of nerves by increasing nerve branching within the corneal epithelium.

  6. Fabrication of narrow-slit masks for the Gemini Multiobject Spectrograph

    NASA Astrophysics Data System (ADS)

    Szeto, Kei; Stilburn, James R.; Bond, Tim; Roberts, Scott; Sebesta, Jerry; Saddlemyer, Leslie K.

    1997-03-01

    The fabrication requirements of the Gemini multi-object spectrograph (GMOS) slit mask is discussed particularly in terms of the slit-to-slit position, slit geometry and the telescope operation. The demand for precision slit masks with high quality slits of width of less than quarter arcsecond and an allowable fabrication time of two hours required examination of innovative fabrication processes and mask materials. Different fabrication processes including high precision cutting processes, water-jet and laser machining systems are evaluated according to cost, speed and efficiency, and the findings are documented. Different candidate mask materials including low thermal expansion metals and novel materials such as graphite paper and carbon-fiber composite sheet, are evaluated according to their relevant mechanical and physical properties, and the findings are also documented. In addition to identifying that the most suitable mask material is unidirectional carbon fiber sheet and the corresponding fabrication process is a Nd:YAG laser machining system, the mask handling system for GMOS is described and methodology to minimize systematic fabrication errors is also proposed.

  7. Influence of blade profile of disc cutter on numerical simulation of the disc slitting process

    NASA Astrophysics Data System (ADS)

    Zeng, J.; Lu, J. B.; Yan, Q. S.; Li, S.

    2015-03-01

    The disc slitting machining experiments for electrical steel sheet were conducted to investigate the wear process of carbide alloy disc cutter and the slitting quality in the disc slitting process, and the blade contour shape of disc cutter in different slitting distance was measured by the surface profiler. A DEFORM-2D model, where the real blade profile or arc fitting profile was used as the blade contour of the cutter, was built to simulate the disc slitting process. Results show that the blade wear of disc cutter increases. The blade wear presents uneven in the side surface and cylindrical surface of the cutter, and the side wear is more serious with the increase of the slitting distance of electrical steel sheet. As the blade wear increases, the height of the rollover increases gradually, the height of the shear area increases at first and then decreases, but the height of the fracture area decreases at first and then increases. Compared with the arc fitting profile, the simulation surface morphology using the real blade profile is in good agreement with the experimental result. The variation of blade profile can change the distribution of the hydrostatic stress of sheet metal and the occurring and propagating of the crack, and the maximum hydrostatic stress can be used to estimate the change tendency of the fracture area.

  8. Are snakes particles or waves? Scattering of a limbless locomotor through a single slit

    NASA Astrophysics Data System (ADS)

    Qian, Feifei; Dai, Jin; Gong, Chaohui; Choset, Howie; Goldman, Daniel

    Droplets on vertically vibrated fluid surfaces can walk and diffract through a single slit by a pilot wave hydrodynamic interaction [Couder, 2006; Bush, 2015]. Inspired by the correspondence between emergent macroscale dynamics and phenomena in quantum systems, we tested if robotic snakes, which resemble wave packets, behave emergently like particles or waves when interacting with an obstacle. In lab experiments and numerical simulations we measured how a multi-module snake-like robot swam through a single slit. We controlled the snake undulation gait as a fixed serpenoid traveling wave pattern with varying amplitude and initial phase, and we examined the snake trajectory as it swam through a slit with width d. Robot trajectories were straight before interaction with the slit, then exited at different scattering angle θ after the interaction due to a complex interaction of the body wave with the slit. For fixed amplitude and large d, the snake passed through the slit with minimal interaction and theta was ~ 0 . For sufficiently small d, θ was finite and bimodally distributed, depending on the initial phase. For intermediate d, θ was sensitive to initial phase, and the width of the distribution of θ increased with decreasing d.

  9. The Slit/Robo System Suppresses Hepatocyte Growth Factor-dependent Invasion and Morphogenesis

    PubMed Central

    Comoglio, Paolo M.

    2009-01-01

    The Slit protein acts through the Roundabout receptor as a paracrine chemorepellent in axon guidance and as an inhibitor in leukocyte chemotaxis, but its role in epithelial cell motility and morphogenesis remains largely unexplored. We report that nontransformed epithelial cells and cancerous cells empower the Slit-2/Robo1 signaling system to limit outward migration in response to motogenic attractants and to remain positionally confined within their primitive location. Short hairpin RNA-mediated depletion of SLIT-2 or ectopic expression of a soluble decoy Robo enhance hepatocyte growth factor (HGF)-induced migration, matrix invasion, and tubulogenesis, concomitantly with the up-regulation of Cdc-42 and the down-modulation of Rac-1 activities. Accordingly, autocrine overexpression or exogenous administration of Slit-2 prevent HGF-triggered motile responses, reduce Cdc-42 activation, and stimulate Rac-1. This antimigratory activity of Slit-2 derives from the inhibition of actin-based protrusive forces and from an increased adhesive strength of cadherin-mediated intercellular contacts. These results disclose a novel function for Slit and Robo in the inhibition of growth factor-mediated epithelial cell motility and morphogenesis, invoking a critical role for both molecules as natural antagonists of neoplastic invasive growth. PMID:19005219

  10. A requirement for filopodia extension toward Slit during Robo-mediated axon repulsion

    PubMed Central

    McConnell, Russell E.; Edward van Veen, J.; Vidaki, Marina; Kwiatkowski, Adam V.; Meyer, Aaron S.

    2016-01-01

    Axons navigate long distances through complex 3D environments to interconnect the nervous system during development. Although the precise spatiotemporal effects of most axon guidance cues remain poorly characterized, a prevailing model posits that attractive guidance cues stimulate actin polymerization in neuronal growth cones whereas repulsive cues induce actin disassembly. Contrary to this model, we find that the repulsive guidance cue Slit stimulates the formation and elongation of actin-based filopodia from mouse dorsal root ganglion growth cones. Surprisingly, filopodia form and elongate toward sources of Slit, a response that we find is required for subsequent axonal repulsion away from Slit. Mechanistically, Slit evokes changes in filopodium dynamics by increasing direct binding of its receptor, Robo, to members of the actin-regulatory Ena/VASP family. Perturbing filopodium dynamics pharmacologically or genetically disrupts Slit-mediated repulsion and produces severe axon guidance defects in vivo. Thus, Slit locally stimulates directional filopodial extension, a process that is required for subsequent axonal repulsion downstream of the Robo receptor. PMID:27091449

  11. Linear Colliders

    NASA Astrophysics Data System (ADS)

    Yamamoto, Akira; Yokoya, Kaoru

    2015-02-01

    An overview of linear collider programs is given. The history and technical challenges are described and the pioneering electron-positron linear collider, the SLC, is first introduced. For future energy frontier linear collider projects, the International Linear Collider (ILC) and the Compact Linear Collider (CLIC) are introduced and their technical features are discussed. The ILC is based on superconducting RF technology and the CLIC is based on two-beam acceleration technology. The ILC collaboration completed the Technical Design Report in 2013, and has come to the stage of "Design to Reality." The CLIC collaboration published the Conceptual Design Report in 2012, and the key technology demonstration is in progress. The prospects for further advanced acceleration technology are briefly discussed for possible long-term future linear colliders.

  12. Linear Colliders

    NASA Astrophysics Data System (ADS)

    Yamamoto, Akira; Yokoya, Kaoru

    An overview of linear collider programs is given. The history and technical challenges are described and the pioneering electron-positron linear collider, the SLC, is first introduced. For future energy frontier linear collider projects, the International Linear Collider (ILC) and the Compact Linear Collider (CLIC) are introduced and their technical features are discussed. The ILC is based on superconducting RF technology and the CLIC is based on two-beam acceleration technology. The ILC collaboration completed the Technical Design Report in 2013, and has come to the stage of "Design to Reality." The CLIC collaboration published the Conceptual Design Report in 2012, and the key technology demonstration is in progress. The prospects for further advanced acceleration technology are briefly discussed for possible long-term future linear colliders.

  13. Pelvic CT scan

    MedlinePlus

    CAT scan - pelvis; Computed axial tomography scan - pelvis; Computed tomography scan - pelvis; CT scan - pelvis ... creates detailed pictures of the body, including the pelvis and areas near the pelvis. The test may ...

  14. Leg CT scan

    MedlinePlus

    CAT scan - leg; Computed axial tomography scan - leg; Computed tomography scan - leg; CT scan - leg ... on film. Three-dimensional (3D) models of the leg can be created by adding the slices together. ...

  15. Abscess scan - radioactive

    MedlinePlus

    Radioactive abscess scan; Abscess scan; Indium Scan; Indium-labelled white blood cell scan ... the white blood cells are tagged with a radioactive substance called indium. The cells are then injected ...

  16. Cooperative signaling between Slit2 and Ephrin-A1 regulates a balance between angiogenesis and angiostasis.

    PubMed

    Dunaway, Charlene M; Hwang, Yoonha; Lindsley, Craig W; Cook, Rebecca S; Wu, Jane Y; Boothby, Mark; Chen, Jin; Brantley-Sieders, Dana M

    2011-02-01

    Slit proteins induce cytoskeletal remodeling through interaction with roundabout (Robo) receptors, regulating migration of neurons and nonneuronal cells, including leukocytes, tumor cells, and endothelium. The role of Slit2 in vascular remodeling, however, remains controversial, with reports of both pro- and antiangiogenic activity. We report here that cooperation between Slit2 and ephrin-A1 regulates a balance between the pro- and antiangiogenic functions of Slit2. While Slit2 promotes angiogenesis in culture and in vivo as a single agent, Slit2 potently inhibits angiogenic remodeling in the presence of ephrin-A1. Slit2 stimulates angiogenesis through mTORC2-dependent activation of Akt and Rac GTPase, the activities of which are inhibited in the presence of ephrin-A1. Activated Rac or Akt partially rescues vascular assembly and motility in costimulated endothelium. Taken together, these data suggest that Slit2 differentially regulates angiogenesis in the context of ephrin-A1, providing a plausible mechanism for the pro- versus antiangiogenic functions of Slit2. Our results suggest that the complex roles of Slit-Robo signaling in angiogenesis involve context-dependent mechanisms.

  17. Slit2-Robo4 pathway modulates lipopolysaccharide-induced endothelial inflammation and its expression is dysregulated during endotoxemia.

    PubMed

    Zhao, Helong; Anand, Appakkudal R; Ganju, Ramesh K

    2014-01-01

    The secretory protein Slit2 and its receptors Robo1 and Robo4 are considered to regulate mobility and permeability of endothelial cells and other cell types. However, the roles of Slit2 and its two receptors in endothelial inflammatory responses remain to be clarified. In this study, we show that, in primary HUVECs, Slit2 represses LPS-induced secretion of certain inflammatory cytokines/chemokines, cell adhesion molecule ICAM-1 upregulation, and monocyte adhesion. Slit2's anti-inflammatory effect is mediated by its dominant endothelial-specific receptor Robo4. However, the minor receptor Robo1 has proinflammatory properties and is downregulated by Slit2 via targeting of miR-218. Elucidation of molecular mechanism reveals that Slit2 represses inflammatory responses by inhibiting the Pyk2-NF-κB pathway downstream of LPS-TLR4. Further studies reveal that LPS enhances endothelial inflammation by downregulating the anti-inflammatory Slit2 and Robo4 in HUVECs in vitro, as well as in arterial endothelial cells and liver in vivo during endotoxemia. These results suggest that Slit2-Robo4 signaling is important in regulating LPS-induced endothelial inflammation, and LPS, in turn, enhances inflammation by interfering with the expression of the anti-inflammatory Slit2-Robo4 during the disease state. This implies that Slit2-Robo4 is a key regulator of endothelial inflammation, and its dysregulation during endotoxemia is a novel mechanism for LPS-induced vascular pathogenesis.

  18. Digital adaptive optics line-scanning confocal imaging system.

    PubMed

    Liu, Changgeng; Kim, Myung K

    2015-01-01

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

  19. Digital adaptive optics line-scanning confocal imaging system

    PubMed Central

    Liu, Changgeng; Kim, Myung K.

    2015-01-01

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

  20. Digital adaptive optics line-scanning confocal imaging system.

    PubMed

    Liu, Changgeng; Kim, Myung K

    2015-01-01

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

  1. Digital adaptive optics line-scanning confocal imaging system

    NASA Astrophysics Data System (ADS)

    Liu, Changgeng; Kim, Myung K.

    2015-11-01

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

  2. A non-signaling role of Robo2 in tendons is essential for Slit processing and muscle patterning.

    PubMed

    Ordan, Elly; Volk, Talila

    2015-10-15

    Coordinated locomotion of an organism relies on the development of proper musculoskeletal connections. In Drosophila, the Slit-Robo signaling pathway guides muscles to tendons. Here, we show that the Slit receptor Roundabout 2 (Robo2) plays a non-cell-autonomous role in directing muscles to their corresponding tendons. Robo2 is expressed by tendons, and its non-signaling activity in these cells promotes Slit cleavage, producing a cleaved Slit N-terminal guidance signal that provides short-range signaling into muscles. Consistently, robo2 mutant embryos exhibited a muscle phenotype similar to that of slit, which could not be rescued by muscle-specific Robo2 expression but rather by ectodermally derived Robo2. Alternatively, this muscle phenotype could be induced by tendon-specific robo2 RNAi. We further show that membrane immobilization of Slit or its N-terminal cleaved form (Slit-N) on tendons bypasses the functional requirement for Robo2 in tendons, verifying that the major role of Robo2 is to promote the association of Slit with the tendon cell membrane. Slit-N tends to oligomerize whereas full-length uncleavable Slit does not. It is therefore proposed that Slit-N oligomers, produced at the tendon membrane by Robo2, signal to the approaching muscle by combined Robo1 and Robo3 activity. These findings establish a Robo2-mediated mechanism, independent of signaling, that is essential to limiting Slit distribution and which might be relevant to the regulation of Slit-mediated short-range signaling in additional systems.

  3. Flat Gauss illumination for the step-and-scan lithographic system

    NASA Astrophysics Data System (ADS)

    Chen, Ming; Wang, Ying; Zeng, Aijun; Zhu, Jing; Yang, Baoxi; Huang, Huijie

    2016-08-01

    To meet the uniform dose exposure in optical lithography, it is desirable to get uniform illumination in the scanning direction on wafer for the step-and-scan lithographic system. We present a flat Gauss illumination for the step-and-scan lithographic system in this paper. Through flat Gauss illumination in scanning direction, pulse quantization effect could be reduced effectively. Correspondingly, the uniformity of the reticle and wafer is improved. Compared with the trapezoid illumination, flat Gauss illumination could keep the slit edge fixed, and pulse quantization effect will not be enhanced. Moreover flat Gauss illumination could be obtained directly without defocusing and blocking, which results in high energy efficiency and high throughput of the lithography. A design strategy for flat Gauss illumination is also proposed which offers high uniformity illumination, fixed slope and integral energy of flat Gauss illumination in different coherence factors. The strategy describes a light uniform device which contains first microlens array, second microlens array, one-dimensional Gauss diffuser and a Fourier lens. The device produces flat Gauss illumination directly at the scanning slit. The design and simulation results show that the uniformity of flat Gauss illumination in two directions satisfy the requirements of lithographic illumination system and the slope. In addition, slit edge of flat Gauss illumination does not change.

  4. Linear Collisions

    ERIC Educational Resources Information Center

    Walkiewicz, T. A.; Newby, N. D., Jr.

    1972-01-01

    A discussion of linear collisions between two or three objects is related to a junior-level course in analytical mechanics. The theoretical discussion uses a geometrical approach that treats elastic and inelastic collisions from a unified point of view. Experiments with a linear air track are described. (Author/TS)

  5. Digital optimeter based on linear CCD

    NASA Astrophysics Data System (ADS)

    Hu, Qing; Xu, Yuanling

    2013-10-01

    In this paper, the development of a new type of digital optimeter based on linear CCD is introduced and discussed. It is based on traditional autocollimation optical system and optical lever motion, with linear CCD as measuring element. A light band generated by slit is captured by linear CCD after passing through an autocollimation optical system. A piece of mirror placed in the optical path of this system is controlled by displacement of a measuring slide in order to adjust the light band imaging position. The displacement of light band is detected by CCD and is then displayed in digital format. Such a design successfully eliminates the existing issues of signal quality and signal overspeed in digital optimeters using grating as the measuring element. The final product based on this technique has been released, offering a resolution of 0.1μm and 0.02μm.

  6. On the cavitation and pore blocking in slit-shaped ink-bottle pores.

    PubMed

    Fan, Chunyan; Do, D D; Nicholson, D

    2011-04-01

    We present GCMC simulations of argon adsorption in slit pores of different channel geometry. We show that the isotherm for an ink-bottle pore can be reconstructed as a linear combination of the local isotherms of appropriately chosen independent unit cells. Second, depending on the system parameters and operating conditions, the phenomena of cavitation and pore blocking can occur for a given configuration of the ink-bottle pore by varying the geometrical aspect ratio. Although it has been argued in the literature that the geometrical aspects of the system govern the evaporation mechanism (either cavitation or pore blocking), we here put forward an argument that the local compressibility in different parts of the ink-bottle pore is the deciding factor for evaporation. When the fluid in the small neck is strongly bound, cavitation is the governing process, and molecules in the cavity evaporate to the surrounding bulk gas via a mass transfer mechanism through the pore neck. When the pore neck is sufficiently large, the system of neck and cavity evaporates at the same pressure, which is a consequence of the comparable compressibility between the fluid in the neck and that in the cavity. This suggests that local compressibility is the measure of cohesiveness of the fluid prior to evaporation. One consequence that we derive from the analysis of isotherms of a number of connected pores is that by analyzing the adsorption branch or the desorption branch of an experimental isotherm may not lead to the correct pore sizes and the correct pore volume distribution. PMID:21370903

  7. The diffusion and relaxation of Gaussian chains in narrow rectangular slits

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, Pinaki; Cherayil, Binny J.

    2013-06-01

    The confinement of a polymer to volumes whose characteristic linear dimensions are comparable to or smaller than its bulk radius of gyration RG,bulk can produce significant changes in its static and dynamic properties, with important implications for the understanding of single-molecule processes in biology and chemistry. In this paper, we present calculations of the effects of a narrow rectangular slit of thickness d on the scaling behavior of the diffusivity D and relaxation time τr of a Gaussian chain of polymerization index N and persistence length l0. The calculations are based on the Rouse-Zimm model of chain dynamics, with the pre-averaged hydrodynamic interaction being obtained from the solutions to Stokes equations for an incompressible fluid in a parallel plate geometry in the limit of small d. They go beyond de Gennes' purely phenomenological analysis of the problem based on blobs, which has so far been the only analytical route to the determination of chain scaling behavior for this particular geometry. The present model predicts that D ˜ dN-1ln (N/d2) and τr ˜ N2d-1[ln (N/d2)]-1 in the regime of moderate confinement, where l0 ≪ d < RG,bulk. The corresponding results for the blob model have exactly the same power law behavior, but contain no logarithmic corrections; the difference suggests that segments within a blob may actually be partially draining and not non-draining as generally assumed.

  8. Pioneer midbrain longitudinal axons navigate using a balance of Netrin attraction and Slit repulsion

    PubMed Central

    2014-01-01

    Background Longitudinal axons grow parallel to the embryonic midline to connect distant regions of the central nervous system. Previous studies suggested that repulsive midline signals guide pioneer longitudinal axons by blocking their entry into the floor plate; however, the role of midline attractants, and whether attractant signals may cooperate with repulsive signals, remains unclear. In this study we investigated the navigation of a set of pioneer longitudinal axons, the medial longitudinal fasciculus, in mouse embryos mutant for the Netrin/Deleted in Colorectal Cancer (DCC) attractants, and for Slit repellents, as well as the responses of explanted longitudinal axons in vitro. Results In mutants for Netrin1 chemoattractant or DCC receptor signaling, longitudinal axons shifted away from the ventral midline, suggesting that Netrin1/DCC signals act attractively to pull axons ventrally. Analysis of mutants in the three Slit genes, including Slit1/2/3 triple mutants, suggest that concurrent repulsive Slit/Robo signals push pioneer axons away from the ventral midline. Combinations of mutations between the Netrin and Slit guidance systems provided genetic evidence that the attractive and repulsive signals balance against each other. This balance is demonstrated in vitro using explant culture, finding that the cues can act directly on longitudinal axons. The explants also reveal an unexpected synergy of Netrin1 and Slit2 that promotes outgrowth. Conclusions These results support a mechanism in which longitudinal trajectories are positioned by a push-pull balance between opposing Netrin and Slit signals. Our evidence suggests that longitudinal axons respond directly and simultaneously to both attractants and repellents, and that the combined signals constrain axons to grow longitudinally. PMID:25056828

  9. Inactivation of SLIT2-ROBO1/2 pathway in premalignant lesions of uterine cervix: clinical and prognostic significances.

    PubMed

    Mitra, Sraboni; Mazumder-Indra, Dipanjana; Mondal, Ranajit K; Basu, Partha S; Roy, Anup; Roychoudhury, Susanta; Panda, Chinmay K

    2012-01-01

    The SLIT2-ROBO1/2 pathways control diverse biological processes, including growth regulation. To understand the role of SLIT2 and ROBO1/2 in cervical carcinogenesis, firstly their RNA expression profiles were screened in 21 primary uterine cervical carcinoma (CACX) samples and two CACX cell lines. Highly reduced expressions of these genes were evident. Concomitant alterations [deletion/methylation] of the genes were then analyzed in 23 cervical intraepithelial neoplasia (CIN) and 110 CACX samples. In CIN, SLIT2 was deleted in 22% samples compared to 9% for ROBO1 and none for ROBO2, whereas comparable methylation was observed for both SLIT2 (30%) and ROBO1 (22%) followed by ROBO2 (9%). In CACX, alteration of the genes were in the following order: Deletion:ROBO1 (48%) > SLIT2 (35%) > ROBO2 (33%), Methylation:SLIT2 (34%) > ROBO1 (29%) > ROBO2 (26%). Overall alterations of SLIT2 and/or ROBO1 (44%) and SLIT2 and/or ROBO2 (39%) were high in CIN followed by significant increase in stage I/II tumors, suggesting deregulation of these interactions in premalignant lesions and early invasive tumors. Immunohistochemical analysis of SLIT2 and ROBO1/2 in CACX also showed reduced expression concordant with molecular alterations. Alteration of all these genes predicted poor patient outcome. Multiparous (≥ 5) women with altered SLIT2 and ROBO1 along with advanced tumor stage (III/IV) and early sexual debut (<19 years) had worst prognosis. Our data suggests the importance of abrogation of SLIT2-ROBO1 and SLIT2-ROBO2 interactions in the initiation and progression of CACX and also for early diagnosis and prognosis of the disease.

  10. Ultrafast scanning tunneling microscopy

    SciTech Connect

    Botkin, D.A. |

    1995-09-01

    I have developed an ultrafast scanning tunneling microscope (USTM) based on uniting stroboscopic methods of ultrafast optics and scanned probe microscopy to obtain nanometer spatial resolution and sub-picosecond temporal resolution. USTM increases the achievable time resolution of a STM by more than 6 orders of magnitude; this should enable exploration of mesoscopic and nanometer size systems on time scales corresponding to the period or decay of fundamental excitations. USTM consists of a photoconductive switch with subpicosecond response time in series with the tip of a STM. An optical pulse from a modelocked laser activates the switch to create a gate for the tunneling current, while a second laser pulse on the sample initiates a dynamic process which affects the tunneling current. By sending a large sequence of identical pulse pairs and measuring the average tunnel current as a function of the relative time delay between the pulses in each pair, one can map the time evolution of the surface process. USTM was used to measure the broadband response of the STM`s atomic size tunnel barrier in frequencies from tens to hundreds of GHz. The USTM signal amplitude decays linearly with the tunnel junction conductance, so the spatial resolution of the time-resolved signal is comparable to that of a conventional STM. Geometrical capacitance of the junction does not appear to play an important role in the measurement, but a capacitive effect intimately related to tunneling contributes to the measured signals and may limit the ultimate resolution of the USTM.

  11. LINEAR ACCELERATOR

    DOEpatents

    Christofilos, N.C.; Polk, I.J.

    1959-02-17

    Improvements in linear particle accelerators are described. A drift tube system for a linear ion accelerator reduces gap capacity between adjacent drift tube ends. This is accomplished by reducing the ratio of the diameter of the drift tube to the diameter of the resonant cavity. Concentration of magnetic field intensity at the longitudinal midpoint of the external sunface of each drift tube is reduced by increasing the external drift tube diameter at the longitudinal center region.

  12. Quantitative trait gene Slit2 positively regulates murine hematopoietic stem cell numbers

    PubMed Central

    Waterstrat, Amanda; Rector, Kyle; Geiger, Hartmut; Liang, Ying

    2016-01-01

    Hematopoietic stem cells (HSC) demonstrate natural variation in number and function. The genetic factors responsible for the variations (or quantitative traits) are largely unknown. We previously identified a gene whose differential expression underlies the natural variation of HSC numbers in C57BL/6 (B6) and DBA/2 (D2) mice. We now report the finding of another gene, Slit2, on chromosome 5 that also accounts for variation in HSC number. In reciprocal chromosome 5 congenic mice, introgressed D2 alleles increased HSC numbers, whereas B6 alleles had the opposite effect. Using gene array and quantitative polymerase chain reaction, we identified Slit2 as a quantitative trait gene whose expression was positively correlated with the number of HSCs. Ectopic expression of Slit2 not only increased the number of the long-term colony forming HSCs, but also enhanced their repopulation capacity upon transplantation. Therefore, Slit2 is a novel quantitative trait gene and a positive regulator of the number and function of murine HSCs. This finding suggests that Slit2 may be a potential therapeutic target for the effective in vitro and in vivo expansion of HSCs without compromising normal hematopoiesis. PMID:27503415

  13. Expression, clinical significance and mechanism of Slit2 in papillary thyroid cancer.

    PubMed

    Shi, Rong-Liang; Qu, Ning; Liao, Tian; Wang, Yu-Long; Wang, Yu; Sun, Guo-Hua; Ji, Qing-Hai

    2016-05-01

    Thyroid cancer is a common endocrine malignancy. The last decade has seen exciting progress in understanding thyroid cancer molecular pathogenesis. Several major signaling pathways and related molecular derangements have been elucidated, which represent novel diagnostic and prognostic molecular markers for thyroid cancer. Based on the molecular biology of thyroid cancer, a series of therapeutic targets have been developed, which provide unprecedented opportunities. Thus, histological characterization of subgroups of patients and the correct molecular characterization of patients are thought to be key aspects for future clinical management of these patients. In the present study, we identified Slit2 as a prognostic marker for thyroid cancer oncogenesis and recurrence. Mechanistically, Slit2 regulated Warburg effect in thyroid cancer cells through regulation of HIF1α and HIF1α transcriptional activity. Taken together, our present data uncovered Slit2 as a novel predictive marker for thyroid cancer. The mechanism study indicated that Slit2 regulated the Warburg effect. Additional study on the function of Slit2 in thyroid cancer is required to provide new insights into the potential mechanisms of oncogenesis and recurrence potential of thyroid cancer.

  14. Quantitative trait gene Slit2 positively regulates murine hematopoietic stem cell numbers.

    PubMed

    Waterstrat, Amanda; Rector, Kyle; Geiger, Hartmut; Liang, Ying

    2016-08-09

    Hematopoietic stem cells (HSC) demonstrate natural variation in number and function. The genetic factors responsible for the variations (or quantitative traits) are largely unknown. We previously identified a gene whose differential expression underlies the natural variation of HSC numbers in C57BL/6 (B6) and DBA/2 (D2) mice. We now report the finding of another gene, Slit2, on chromosome 5 that also accounts for variation in HSC number. In reciprocal chromosome 5 congenic mice, introgressed D2 alleles increased HSC numbers, whereas B6 alleles had the opposite effect. Using gene array and quantitative polymerase chain reaction, we identified Slit2 as a quantitative trait gene whose expression was positively correlated with the number of HSCs. Ectopic expression of Slit2 not only increased the number of the long-term colony forming HSCs, but also enhanced their repopulation capacity upon transplantation. Therefore, Slit2 is a novel quantitative trait gene and a positive regulator of the number and function of murine HSCs. This finding suggests that Slit2 may be a potential therapeutic target for the effective in vitro and in vivo expansion of HSCs without compromising normal hematopoiesis.

  15. Stromal SLIT2 impacts on pancreatic cancer-associated neural remodeling.

    PubMed

    Secq, V; Leca, J; Bressy, C; Guillaumond, F; Skrobuk, P; Nigri, J; Lac, S; Lavaut, M-N; Bui, T-T; Thakur, A K; Callizot, N; Steinschneider, R; Berthezene, P; Dusetti, N; Ouaissi, M; Moutardier, V; Calvo, E; Bousquet, C; Garcia, S; Bidaut, G; Vasseur, S; Iovanna, J L; Tomasini, R

    2015-01-15

    Pancreatic ductal adenocarcinoma (PDA) is a critical health issue in the field of cancer, with few therapeutic options. Evidence supports an implication of the intratumoral microenvironment (stroma) on PDA progression. However, its contribution to the role of neuroplastic changes within the pathophysiology and clinical course of PDA, through tumor recurrence and neuropathic pain, remains unknown, neglecting a putative, therapeutic window. Here, we report that the intratumoral microenvironment is a mediator of PDA-associated neural remodeling (PANR), and we highlight factors such as 'SLIT2' (an axon guidance molecule), which is expressed by cancer-associated fibroblasts (CAFs), that impact on neuroplastic changes in human PDA. We showed that 'CAF-secreted SLIT2' increases neurite outgrowth from dorsal root ganglia neurons as well as from Schwann cell migration/proliferation by modulating N-cadherin/β-catenin signaling. Importantly, SLIT2/ROBO signaling inhibition disrupts this stromal/neural connection. Finally, we revealed that SLIT2 expression and CAFs are correlated with neural remodeling within human and mouse PDA. All together, our data demonstrate the implication of CAFs, through the secretion of axon guidance molecule, in PANR. Furthermore, it provides rationale to investigate the disruption of the stromal/neural compartment connection with SLIT2/ROBO inhibitors for the treatment of pancreatic cancer recurrence and pain.

  16. Frizzled-3a and slit2 genetically interact to modulate midline axon crossing in the telencephalon.

    PubMed

    Hofmeister, Wolfgang; Devine, Christine A; Rothnagel, Joseph A; Key, Brian

    2012-07-01

    The anterior commissure forms the first axon connections between the two sides of the embryonic telencephalon. We investigated the role of the transmembrane receptor Frizzled-3a in the development of this commissure using zebrafish as an experimental model. Knock down of Frizzled-3a resulted in complete loss of the anterior commissure. This defect was accompanied by a loss of the glial bridge, expansion of the slit2 expression domain and perturbation of the midline telencephalic-diencephalic boundary. Blocking Slit2 activity following knock down of Frizzled-3a effectively rescued the anterior commissure defect which suggested that Frizzled-3a was indirectly controlling the growth of axons across the rostral midline. We have shown here that Frizzled-3a is essential for normal development of the commissural plate and that loss-of-function causes Slit2-dependent defects in axon midline crossing in the embryonic vertebrate forebrain. These data supports a model whereby Wnt signaling through Frizzled-3a attenuates expression of Slit2 in the rostral midline of the forebrain. The absence of Slit2 facilitates the formation of a midline bridge of glial cells which is used as a substrate for commissural axons. In the absence of this platform of glia, commissural axons fail to cross the rostral midline of the forebrain.

  17. Analysis of transmission through slit and multiple grooves structures for biosensors

    NASA Astrophysics Data System (ADS)

    Kim, Bong Ho; Nakarmi, Bikash; Won, Yong Hyub

    2015-03-01

    We analyze the transmission property of nanostructures made on silver and gold metal for the applications in optical biosensors. Various structures such as slit only, slit groove slit, and multiple slit and groove structures are taken into account to find the effect of various physical parameters such as number of grooves, number of slits and others on the transmission of different wavelength light sources through the structure. A broad wavelength of 400 nm to 900 nm is used to analyze the transmission through the structure. With these structures and broad light source, change in transmission intensity is analyzed with the change in the refractive index. The change in refractive index of the analyte varies transmission intensity and wavelength shift at the output beam which can be used for sensing the amount of analyte such as monitoring glucose amount on blood/saliva, hydrogen peroxide and others. The detection of these analytes can be used to detect the different disease. The analysis of the transmittance through the nanostructure can be used for the detection of several disease such as diabetes and others through the saliva, blood and others non-invasively.

  18. Convergent differential regulation of SLIT-ROBO axon guidance genes in the brains of vocal learners.

    PubMed

    Wang, Rui; Chen, Chun-Chun; Hara, Erina; Rivas, Miriam V; Roulhac, Petra L; Howard, Jason T; Chakraborty, Mukta; Audet, Jean-Nicolas; Jarvis, Erich D

    2015-04-15

    Only a few distantly related mammals and birds have the trait of complex vocal learning, which is the ability to imitate novel sounds. This ability is critical for speech acquisition and production in humans, and is attributed to specialized forebrain vocal control circuits that have several unique connections relative to adjacent brain circuits. As a result, it has been hypothesized that there could exist convergent changes in genes involved in neural connectivity of vocal learning circuits. In support of this hypothesis, expanding on our related study (Pfenning et al. [2014] Science 346: 1256846), here we show that the forebrain part of this circuit that makes a relatively rare direct connection to brainstem vocal motor neurons in independent lineages of vocal learning birds (songbird, parrot, and hummingbird) has specialized regulation of axon guidance genes from the SLIT-ROBO molecular pathway. The SLIT1 ligand was differentially downregulated in the motor song output nucleus that makes the direct projection, whereas its receptor ROBO1 was developmentally upregulated during critical periods for vocal learning. Vocal nonlearning bird species and male mice, which have much more limited vocal plasticity and associated circuits, did not show comparable specialized regulation of SLIT-ROBO genes in their nonvocal motor cortical regions. These findings are consistent with SLIT and ROBO gene dysfunctions associated with autism, dyslexia, and speech sound language disorders and suggest that convergent evolution of vocal learning was associated with convergent changes in the SLIT-ROBO axon guidance pathway.

  19. Final report on LDRD project : biodiesel production from vegetable oils using slit-channel reactors.

    SciTech Connect

    Kalu, E. Eric; Chen, Ken Shuang

    2008-01-01

    This report documents work done for a late-start LDRD project, which was carried out during the last quarter of FY07. The objective of this project was to experimentally explore the feasibility of converting vegetable (e.g., soybean) oils to biodiesel by employing slit-channel reactors and solid catalysts. We first designed and fabricated several slit-channel reactors with varying channel depths, and employed them to investigate the improved performance of slit-channel reactors over traditional batch reactors using a NaOH liquid catalyst. We then evaluated the effectiveness of several solid catalysts, including CaO, ZnO, MgO, ZrO{sub 2}, calcium gluconate, and heteropolyacid or HPA (Cs{sub 2.5}H{sub 0.5}PW{sub 12}O{sub 40}), for catalyzing the soybean oil-to-biodiesel transesterification reaction. We found that the slit-channel reactor performance improves as channel depth decreases, as expected; and the conversion efficiency of a slit-channel reactor is significantly higher when its channel is very shallow. We further confirmed CaO as having the highest catalytic activity among the solid catalysts tested, and we demonstrated for the first time calcium gluconate as a promising solid catalyst for converting soybean oil to biodiesel, based on our preliminary batch-mode conversion experiments.

  20. Quantitative trait gene Slit2 positively regulates murine hematopoietic stem cell numbers.

    PubMed

    Waterstrat, Amanda; Rector, Kyle; Geiger, Hartmut; Liang, Ying

    2016-01-01

    Hematopoietic stem cells (HSC) demonstrate natural variation in number and function. The genetic factors responsible for the variations (or quantitative traits) are largely unknown. We previously identified a gene whose differential expression underlies the natural variation of HSC numbers in C57BL/6 (B6) and DBA/2 (D2) mice. We now report the finding of another gene, Slit2, on chromosome 5 that also accounts for variation in HSC number. In reciprocal chromosome 5 congenic mice, introgressed D2 alleles increased HSC numbers, whereas B6 alleles had the opposite effect. Using gene array and quantitative polymerase chain reaction, we identified Slit2 as a quantitative trait gene whose expression was positively correlated with the number of HSCs. Ectopic expression of Slit2 not only increased the number of the long-term colony forming HSCs, but also enhanced their repopulation capacity upon transplantation. Therefore, Slit2 is a novel quantitative trait gene and a positive regulator of the number and function of murine HSCs. This finding suggests that Slit2 may be a potential therapeutic target for the effective in vitro and in vivo expansion of HSCs without compromising normal hematopoiesis. PMID:27503415

  1. Convergent differential regulation of SLIT-ROBO axon guidance genes in the brains of vocal learners.

    PubMed

    Wang, Rui; Chen, Chun-Chun; Hara, Erina; Rivas, Miriam V; Roulhac, Petra L; Howard, Jason T; Chakraborty, Mukta; Audet, Jean-Nicolas; Jarvis, Erich D

    2015-04-15

    Only a few distantly related mammals and birds have the trait of complex vocal learning, which is the ability to imitate novel sounds. This ability is critical for speech acquisition and production in humans, and is attributed to specialized forebrain vocal control circuits that have several unique connections relative to adjacent brain circuits. As a result, it has been hypothesized that there could exist convergent changes in genes involved in neural connectivity of vocal learning circuits. In support of this hypothesis, expanding on our related study (Pfenning et al. [2014] Science 346: 1256846), here we show that the forebrain part of this circuit that makes a relatively rare direct connection to brainstem vocal motor neurons in independent lineages of vocal learning birds (songbird, parrot, and hummingbird) has specialized regulation of axon guidance genes from the SLIT-ROBO molecular pathway. The SLIT1 ligand was differentially downregulated in the motor song output nucleus that makes the direct projection, whereas its receptor ROBO1 was developmentally upregulated during critical periods for vocal learning. Vocal nonlearning bird species and male mice, which have much more limited vocal plasticity and associated circuits, did not show comparable specialized regulation of SLIT-ROBO genes in their nonvocal motor cortical regions. These findings are consistent with SLIT and ROBO gene dysfunctions associated with autism, dyslexia, and speech sound language disorders and suggest that convergent evolution of vocal learning was associated with convergent changes in the SLIT-ROBO axon guidance pathway. PMID:25424606

  2. Simulation of femtosecond "double-slit" experiments for a chromophore in a dissipative environment.

    PubMed

    Gelin, M F; Tanimura, Y; Domcke, W

    2013-12-01

    We performed simulations of the prototypical femtosecond "double-slit" experiment with strong pulsed laser fields for a chromophore in solution. The chromophore is modeled as a system with two electronic levels and a single Franck-Condon active underdamped vibrational mode. All other (intra- and inter-molecular) vibrational modes are accounted for as a thermal bath. The system-bath coupling is treated in a computationally accurate manner using the hierarchy equations of motion approach. The double-slit signal is evaluated numerically exactly without invoking perturbation theory in the matter-field interaction. We show that the strong-pulse double-slit signal consists of a superposition of N-wave-mixing (N = 2, 4, 6...) responses and can be split into population and coherence contributions. The former reveals the dynamics of vibrational wave packets in the ground state and the excited electronic state of the chromophore, while the latter contains information on the dephasing of electronic coherences of the chromophore density matrix. We studied the influence of heat baths with different coupling strengths and memories on the double-slit signal. Our results show that the double-slit experiment performed with strong (nonperturbative) pulses yields substantially more information on the photoinduced dynamics of the chromophore than the weak-pulse experiment, in particular, if the bath-induced dephasings are fast.

  3. Simulation of femtosecond ``double-slit'' experiments for a chromophore in a dissipative environment

    NASA Astrophysics Data System (ADS)

    Gelin, M. F.; Tanimura, Y.; Domcke, W.

    2013-12-01

    We performed simulations of the prototypical femtosecond "double-slit" experiment with strong pulsed laser fields for a chromophore in solution. The chromophore is modeled as a system with two electronic levels and a single Franck-Condon active underdamped vibrational mode. All other (intra- and inter-molecular) vibrational modes are accounted for as a thermal bath. The system-bath coupling is treated in a computationally accurate manner using the hierarchy equations of motion approach. The double-slit signal is evaluated numerically exactly without invoking perturbation theory in the matter-field interaction. We show that the strong-pulse double-slit signal consists of a superposition of N-wave-mixing (N = 2, 4, 6…) responses and can be split into population and coherence contributions. The former reveals the dynamics of vibrational wave packets in the ground state and the excited electronic state of the chromophore, while the latter contains information on the dephasing of electronic coherences of the chromophore density matrix. We studied the influence of heat baths with different coupling strengths and memories on the double-slit signal. Our results show that the double-slit experiment performed with strong (nonperturbative) pulses yields substantially more information on the photoinduced dynamics of the chromophore than the weak-pulse experiment, in particular, if the bath-induced dephasings are fast.

  4. Slits Affect the Timely Migration of Neural Crest Cells via Robo Receptor

    PubMed Central

    Giovannone, Dion; Reyes, Michelle; Reyes, Rachel; Correa, Lisa; Martinez, Darwin; Ra, Hannah; Gomez, Gustavo; Kaiser, Josh; Ma, Le; Stein, Mary-Pat; de Bellard, Maria Elena

    2013-01-01

    SUMMARY Background Neural crest cells emerge by delamination from the dorsal neural tube and give rise to various components of the peripheral nervous system in vertebrate embryos. These cells change from non-motile into highly motile cells migrating to distant areas before further differentiation. Mechanisms controlling delamination and subsequent migration of neural crest cells are not fully understood. Slit2, a chemorepellant for axonal guidance that repels and stimulates motility of trunk neural crest cells away from the gut has recently been suggested to be a tumor suppressor molecule. The goal of this study was to further investigate the role of Slit2 in trunk neural crest cell migration by constitutive expression in neural crest cells. Results We found that Slit gain-of-function significantly impaired neural crest cell migration while Slit loss-of-function favored migration. In addition, we observed that the distribution of key cytoskeletal markers was disrupted in both gain and loss of function instances. Conclusions These findings suggest that Slit molecules might be involved in the processes that allow neural crest cells to begin migration and transitioning to a mesenchymal type. PMID:22689303

  5. Slit2 regulates attractive eosinophil and repulsive neutrophil chemotaxis through differential srGAP1 expression during lung inflammation.

    PubMed

    Ye, Bu-Qing; Geng, Zhen H; Ma, Li; Geng, Jian-Guo

    2010-11-15

    Directional migration of leukocytes is an essential step in leukocyte trafficking during inflammatory responses. However, the molecular mechanisms governing directional chemotaxis of leukocytes remain poorly understood. The Slit family of guidance cues has been implicated for inhibition of leuocyte migration. We report that Clara cells in the bronchial epithelium secreted Slit2, whereas eosinophils and neutrophils expressed its cell-surface receptor, Robo1. Compared to neutrophils, eosinophils exhibited a significantly lower level of Slit-Robo GTPase-activating protein 1 (srGAP1), leading to activation of Cdc42, recruitment of PI3K to Robo1, enhancment of eotaxin-induced eosinophil chemotaxis, and exaggeration of allergic airway inflammation. Notably, OVA sensitization elicited a Slit2 gradient at so-called bronchus-alveoli axis, with a higher level of Slit2 in the bronchial epithelium and a lower level in the alveolar tissue. Aerosol administration of rSlit2 accelerated eosinophil infiltration, whereas i.v. administered Slit2 reduced eosinophil deposition. In contrast, Slit2 inactivated Cdc42 and suppressed stromal cell-derived factor-1α-induced chemotaxis of neutrophils for inhibiting endotoxin-induced lung inflammation, which were reversed by blockade of srGAP1 binding to Robo1. These results indicate that the newly identified Slit2 gradient at the bronchus-alveoli axis induces attractive PI3K signaling in eosinophils and repulsive srGAP1 signaling in neutrophils through differential srGAP1 expression during lung inflammation.

  6. Scanning scene tunnel for city traversing.

    PubMed

    Zheng, Jiang Yu; Zhou, Yu; Milli, Panayiotis

    2006-01-01

    This paper proposes a visual representation named scene tunnel for capturing urban scenes along routes and visualizing them on the Internet. We scan scenes with multiple cameras or a fish-eye camera on a moving vehicle, which generates a real scene archive along streets that is more complete than previously proposed route panoramas. Using a translating spherical eye, properly set planes of scanning, and unique parallel-central projection, we explore the image acquisition of the scene tunnel from camera selection and alignment, slit calculation, scene scanning, to image integration. The scene tunnels cover high buildings, ground, and various viewing directions and have uniformed resolutions along the street. The sequentially organized scene tunnel benefits texture mapping onto the urban models. We analyze the shape characteristics in the scene tunnels for designing visualization algorithms. After combining this with a global panorama and forward image caps, the capped scene tunnels can provide continuous views directly for virtual or real navigation in a city. We render scene tunnel dynamically by view warping, fast transmission, and flexible interaction. The compact and continuous scene tunnel facilitates model construction, data streaming, and seamless route traversing on the Internet and mobile devices.

  7. Scanning scene tunnel for city traversing.

    PubMed

    Zheng, Jiang Yu; Zhou, Yu; Milli, Panayiotis

    2006-01-01

    This paper proposes a visual representation named scene tunnel for capturing urban scenes along routes and visualizing them on the Internet. We scan scenes with multiple cameras or a fish-eye camera on a moving vehicle, which generates a real scene archive along streets that is more complete than previously proposed route panoramas. Using a translating spherical eye, properly set planes of scanning, and unique parallel-central projection, we explore the image acquisition of the scene tunnel from camera selection and alignment, slit calculation, scene scanning, to image integration. The scene tunnels cover high buildings, ground, and various viewing directions and have uniformed resolutions along the street. The sequentially organized scene tunnel benefits texture mapping onto the urban models. We analyze the shape characteristics in the scene tunnels for designing visualization algorithms. After combining this with a global panorama and forward image caps, the capped scene tunnels can provide continuous views directly for virtual or real navigation in a city. We render scene tunnel dynamically by view warping, fast transmission, and flexible interaction. The compact and continuous scene tunnel facilitates model construction, data streaming, and seamless route traversing on the Internet and mobile devices. PMID:16509375

  8. Correcting nonlinear drift distortion of scanning probe and scanning transmission electron microscopies from image pairs with orthogonal scan directions.

    PubMed

    Ophus, Colin; Ciston, Jim; Nelson, Chris T

    2016-03-01

    Unwanted motion of the probe with respect to the sample is a ubiquitous problem in scanning probe and scanning transmission electron microscopies, causing both linear and nonlinear artifacts in experimental images. We have designed a procedure to correct these artifacts by using orthogonal scan pairs to align each measurement line-by-line along the slow scan direction, by fitting contrast variation along the lines. We demonstrate the accuracy of our algorithm on both synthetic and experimental data and provide an implementation of our method.

  9. Gallbladder radionuclide scan

    MedlinePlus

    Radionuclide - gallbladder; Gallbladder scan; Biliary scan; Cholescintigraphy: HIDA; Hepatobiliary nuclear imaging scan ... small amount of morphine. This can help the radionuclide get into the gallbladder. The morphine may cause ...

  10. Coronary Calcium Scan

    MedlinePlus

    ... the NHLBI on Twitter. What Is a Coronary Calcium Scan? A coronary calcium scan is a test ... you have calcifications in your coronary arteries. Coronary Calcium Scan Figure A shows the position of the ...

  11. Density functional study of chemical reaction equilibrium for dimerization reactions in slit and cylindrical nanopores.

    PubMed

    Malijevský, Alexandr; Lísal, Martin

    2009-04-28

    We present a theoretical study of the effects of confinement on chemical reaction equilibrium in slit and cylindrical nanopores. We use a density functional theory (DFT) to investigate the effects of temperature, pore geometry, bulk pressure, transition layering, and capillary condensation on a dimerization reaction that mimics the nitric oxide dimerization reaction, 2NO <==> (NO)(2), in carbonlike slit and cylindrical nanopores in equilibrium with a vapor reservoir. In addition to the DFT calculations, we also utilize the reaction ensemble Monte Carlo method to supplement the DFT results for reaction conversion. This work is an extension of the previous DFT study by Tripathi and Chapman [J. Chem. Phys. 118, 7993 (2003)] on the dimerization reactions confined in the planar slits.

  12. Imaging of surface plasmon polariton fields excited at a nanometer-scale slit

    NASA Astrophysics Data System (ADS)

    Zhang, Lingxiao; Kubo, Atsushi; Wang, Leiming; Petek, Hrvoje; Seideman, Tamar

    2011-12-01

    Nonlinear two-photon photoemission electron microscopy is used to image surface plasmon polariton (SPP) wave packets excited by an obliquely incident laser pulse (˜10 fs) at a single slit fabricated in a thin silver film. We image the forward propagating polarization grating formed by the coherent superposition of the external excitation pulse and the SPP wave packet fields. By systematically varying the coupling slit width from sub- to multiple-wavelength scale, we observe a modulated increase of the grating intensity, which is phenomenologically accounted for by distinct contributions to the forward coupling efficiency from the incident to the SPP waves. Full wave, vectorial finite-difference time-domain (FDTD) simulation of the experiments is in good agreement with the experimental observations and explains their origin. In particular, the FDTD simulation illustrates detailed spatial variation of the polarization grating as a function of the geometry of the slit under excitation by ultrafast laser pulses at an oblique incidence.

  13. Fraunhofer diffraction of a slit aperture between a knife-edge and a metal cylinder.

    PubMed

    Fukaya, J; Sasaki, A; Matsuda, Y; Aoyama, H

    1995-12-01

    The Fraunhofer diffraction pattern of a slit aperture formed between a reference knife-edge and a metal-cylinder surface is different from that of an ideal slit aperture. This pattern should include reflected light coming from both the front and rear sides of a cylinder surface. To investigate the influence of light reflected from the cylinder surface, we discuss the theoretical consideration based on the simple model of the reflected light on the surface. The experimental setup is designed and constructed to measure the actual diffraction pattern produced by the slit between the knife-edge and the cylinder surface. As a result it is obvious that the reflection of diffracted light on the rear side is dominant in both the simulation and the experiment.

  14. Controlling surface-plasmon-polaritons launching with hot spot cylindrical waves in a metallic slit structure.

    PubMed

    Yao, Wenjie; Sun, Chengwei; Gong, Qihuang; Chen, Jianjun

    2016-09-23

    Plasmonic nanostructures, which are used to generate surface plasmon polaritons (SPPs), always involve sharp corners where the charges can accumulate. This can result in strong localized electromagnetic fields at the metallic corners, forming the hot spots. The influence of the hot spots on the propagating SPPs are investigated theoretically and experimentally in a metallic slit structure. It is found that the electromagnetic fields radiated from the hot spots, termed as the hot spot cylindrical wave (HSCW), can greatly manipulate the SPP launching in the slit structure. The physical mechanism behind the manipulation of the SPP launching with the HSCW is explicated by a semi-analytic model. By using the HSCW, unidirectional SPP launching is experimentally realized in an ultra-small metallic step-slit structure. The HSCW bridges the localized surface plasmons and the propagating surface plasmons in an integrated platform and thus may pave a new route to the design of plasmonic devices and circuits.

  15. Narrow gaps for transmission through metallic structured gratings with subwavelength slits.

    PubMed

    Skigin, Diana C; Depine, Ricardo A

    2006-10-01

    Transmission dips in the response of metallic compound gratings formed by several wires and slits in each period have been recently reported for normal illumination. These anomalies are generated by a particular arrangement of the magnetic field phases inside the subwavelength slits, and they are characterized by a significant enhancement of the interior field. We investigate the microwave response of such systems under non-normal illumination and show that new phase modes appear in this configuration. Contrary to the effect produced by a defect in a photonic crystal, these systems exhibit forbidden channels within a permitted band. We also found that the appearance of these resonances is not highly dependent on the slits' width and thickness, even though these parameters modify the overall transmittance.

  16. Controlling surface-plasmon-polaritons launching with hot spot cylindrical waves in a metallic slit structure

    NASA Astrophysics Data System (ADS)

    Yao, Wenjie; Sun, Chengwei; Gong, Qihuang; Chen, Jianjun

    2016-09-01

    Plasmonic nanostructures, which are used to generate surface plasmon polaritons (SPPs), always involve sharp corners where the charges can accumulate. This can result in strong localized electromagnetic fields at the metallic corners, forming the hot spots. The influence of the hot spots on the propagating SPPs are investigated theoretically and experimentally in a metallic slit structure. It is found that the electromagnetic fields radiated from the hot spots, termed as the hot spot cylindrical wave (HSCW), can greatly manipulate the SPP launching in the slit structure. The physical mechanism behind the manipulation of the SPP launching with the HSCW is explicated by a semi-analytic model. By using the HSCW, unidirectional SPP launching is experimentally realized in an ultra-small metallic step-slit structure. The HSCW bridges the localized surface plasmons and the propagating surface plasmons in an integrated platform and thus may pave a new route to the design of plasmonic devices and circuits.

  17. Young's double-slit interference observation of hot electrons in semiconductors.

    PubMed

    Furuya, Kazuhito; Ninomiya, Yasunori; Machida, Nobuya; Miyamoto, Yasuyuki

    2003-11-21

    We have carried out Young's double-slit experiment for the hot-electron wave in man-made semiconductor structures with a 25-nm-space double slit in an InP layer buried within GaInAs, a 190-nm-thick GaInAsP hot-electron wave propagation layer, and a collector array of 80 nm pitch. At 4.2 K, dependences of the collector current on the magnetic field were measured and found to agree clearly with the double-slit interference theory. The present results show evidence for the wave front spread of hot electrons using the three-dimensional state in materials, for the first time, and the possibility of using top-down fabrication techniques to achieve quantum wave front control in materials.

  18. Measurement-induced decoherence and information in double-slit interference

    NASA Astrophysics Data System (ADS)

    Kincaid, Joshua; McLelland, Kyle; Zwolak, Michael

    2016-07-01

    The double slit experiment provides a classic example of both interference and the effect of observation in quantum physics. When particles are sent individually through a pair of slits, a wave-like interference pattern develops, but no such interference is found when one observes which "path" the particles take. We present a model of interference, dephasing, and measurement-induced decoherence in a one-dimensional version of the double-slit experiment. Using this model, we demonstrate how the loss of interference in the system is correlated with the information gain by the measuring apparatus/observer. In doing so, we give a modern account of measurement in this paradigmatic example of quantum physics that is accessible to students taking quantum mechanics at the graduate or senior undergraduate levels.

  19. Electronically tunable extraordinary optical transmission in graphene plasmonic ribbons coupled to subwavelength metallic slit arrays

    NASA Astrophysics Data System (ADS)

    Kim, Seyoon; Jang, Min Seok; Brar, Victor W.; Tolstova, Yulia; Mauser, Kelly W.; Atwater, Harry A.

    2016-08-01

    Subwavelength metallic slit arrays have been shown to exhibit extraordinary optical transmission, whereby tunnelling surface plasmonic waves constructively interfere to create large forward light propagation. The intricate balancing needed for this interference to occur allows for resonant transmission to be highly sensitive to changes in the environment. Here we demonstrate that extraordinary optical transmission resonance can be coupled to electrostatically tunable graphene plasmonic ribbons to create electrostatic modulation of mid-infrared light. Absorption in graphene plasmonic ribbons situated inside metallic slits can efficiently block the coupling channel for resonant transmission, leading to a suppression of transmission. Full-wave simulations predict a transmission modulation of 95.7% via this mechanism. Experimental measurements reveal a modulation efficiency of 28.6% in transmission at 1,397 cm-1, corresponding to a 2.67-fold improvement over transmission without a metallic slit array. This work paves the way for enhancing light modulation in graphene plasmonics by employing noble metal plasmonic structures.

  20. Measurement-induced decoherence and information in double-slit interference

    PubMed Central

    Kincaid, Joshua; McLelland, Kyle; Zwolak, Michael

    2016-01-01

    The double slit experiment provides a classic example of both interference and the effect of observation in quantum physics. When particles are sent individually through a pair of slits, a wave-like interference pattern develops, but no such interference is found when one observes which “path” the particles take. We present a model of interference, dephasing, and measurement-induced decoherence in a one-dimensional version of the double-slit experiment. Using this model, we demonstrate how the loss of interference in the system is correlated with the information gain by the measuring apparatus/observer. In doing so, we give a modern account of measurement in this paradigmatic example of quantum physics that is accessible to students taking quantum mechanics at the graduate or senior undergraduate levels. PMID:27807373

  1. Controlling surface-plasmon-polaritons launching with hot spot cylindrical waves in a metallic slit structure.

    PubMed

    Yao, Wenjie; Sun, Chengwei; Gong, Qihuang; Chen, Jianjun

    2016-09-23

    Plasmonic nanostructures, which are used to generate surface plasmon polaritons (SPPs), always involve sharp corners where the charges can accumulate. This can result in strong localized electromagnetic fields at the metallic corners, forming the hot spots. The influence of the hot spots on the propagating SPPs are investigated theoretically and experimentally in a metallic slit structure. It is found that the electromagnetic fields radiated from the hot spots, termed as the hot spot cylindrical wave (HSCW), can greatly manipulate the SPP launching in the slit structure. The physical mechanism behind the manipulation of the SPP launching with the HSCW is explicated by a semi-analytic model. By using the HSCW, unidirectional SPP launching is experimentally realized in an ultra-small metallic step-slit structure. The HSCW bridges the localized surface plasmons and the propagating surface plasmons in an integrated platform and thus may pave a new route to the design of plasmonic devices and circuits. PMID:27533591

  2. Double-slit experiment with single wave-driven particles and its relation to quantum mechanics

    NASA Astrophysics Data System (ADS)

    Andersen, Anders; Madsen, Jacob; Reichelt, Christian; Rosenlund Ahl, Sonja; Lautrup, Benny; Ellegaard, Clive; Levinsen, Mogens T.; Bohr, Tomas

    2015-07-01

    In a thought-provoking paper, Couder and Fort [Phys. Rev. Lett. 97, 154101 (2006), 10.1103/PhysRevLett.97.154101] describe a version of the famous double-slit experiment performed with droplets bouncing on a vertically vibrated fluid surface. In the experiment, an interference pattern in the single-particle statistics is found even though it is possible to determine unambiguously which slit the walking droplet passes. Here we argue, however, that the single-particle statistics in such an experiment will be fundamentally different from the single-particle statistics of quantum mechanics. Quantum mechanical interference takes place between different classical paths with precise amplitude and phase relations. In the double-slit experiment with walking droplets, these relations are lost since one of the paths is singled out by the droplet. To support our conclusions, we have carried out our own double-slit experiment, and our results, in particular the long and variable slit passage times of the droplets, cast strong doubt on the feasibility of the interference claimed by Couder and Fort. To understand theoretically the limitations of wave-driven particle systems as analogs to quantum mechanics, we introduce a Schrödinger equation with a source term originating from a localized particle that generates a wave while being simultaneously guided by it. We show that the ensuing particle-wave dynamics can capture some characteristics of quantum mechanics such as orbital quantization. However, the particle-wave dynamics can not reproduce quantum mechanics in general, and we show that the single-particle statistics for our model in a double-slit experiment with an additional splitter plate differs qualitatively from that of quantum mechanics.

  3. Double-slit experiment with single wave-driven particles and its relation to quantum mechanics.

    PubMed

    Andersen, Anders; Madsen, Jacob; Reichelt, Christian; Rosenlund Ahl, Sonja; Lautrup, Benny; Ellegaard, Clive; Levinsen, Mogens T; Bohr, Tomas

    2015-07-01

    In a thought-provoking paper, Couder and Fort [Phys. Rev. Lett. 97, 154101 (2006)] describe a version of the famous double-slit experiment performed with droplets bouncing on a vertically vibrated fluid surface. In the experiment, an interference pattern in the single-particle statistics is found even though it is possible to determine unambiguously which slit the walking droplet passes. Here we argue, however, that the single-particle statistics in such an experiment will be fundamentally different from the single-particle statistics of quantum mechanics. Quantum mechanical interference takes place between different classical paths with precise amplitude and phase relations. In the double-slit experiment with walking droplets, these relations are lost since one of the paths is singled out by the droplet. To support our conclusions, we have carried out our own double-slit experiment, and our results, in particular the long and variable slit passage times of the droplets, cast strong doubt on the feasibility of the interference claimed by Couder and Fort. To understand theoretically the limitations of wave-driven particle systems as analogs to quantum mechanics, we introduce a Schrödinger equation with a source term originating from a localized particle that generates a wave while being simultaneously guided by it. We show that the ensuing particle-wave dynamics can capture some characteristics of quantum mechanics such as orbital quantization. However, the particle-wave dynamics can not reproduce quantum mechanics in general, and we show that the single-particle statistics for our model in a double-slit experiment with an additional splitter plate differs qualitatively from that of quantum mechanics.

  4. Potential Role of Axonal Chemorepellent Slit2 in Modulating Adventitial Inflammation in a Rat Carotid Artery Balloon Injury Model.

    PubMed

    Liu, Dong; Xiao, Yan; Subramanian, Romesh R; Okamoto, Ei-Ichi; Wilcox, Josiah N; Anderson, Leonard; De Leon, Hector

    2016-05-01

    Leukocyte infiltration of adventitial and perivascular tissues is an early event in the development of vascular remodeling after injury. We investigated whether Slit/Robo-an axonal chemorepellent system in vertebrate and invertebrate development-is activated during the inflammatory phase that follows endothelial denudation. Using the rat carotid artery model of angioplasty, we conducted a time course analysis of mRNAs encoding Slit ligands (Slit2 and Slit3) and Robo receptors (Robo1, Robo2, and Robo4), as well as proinflammatory cell adhesion molecule (CAM) genes. Adventitial inflammatory cells were counted in immunostained arterial sections. E-selectin, vascular CAM-1, and intercellular CAM-1 were upregulated 2-3 hours after injury, followed by infiltration of neutrophils and monocytes as evidenced by real-time polymerase chain reaction, in situ hybridization, and immunohistochemistry. Slit2, Slit3, and Robo genes exhibited no expression changes at 3 hours; however, they were markedly upregulated 1 day after angioplasty. Intercellular CAM-1 expression was reduced by 50%, and the number of adventitial neutrophils decreased by >75% 1 day after angioplasty. Slit2 has been shown to be a potent chemorepelent of leukocytes, endothelial cells, and smooth muscle cells. Thus, we decided to further investigate the localization of Slit2 in injured vessels. Immunohistochemical stainings revealed the presence of Slit2 within the vessel wall and in the perivascular vasa vasorum of naive and injured arteries. Double immunohistochemical analyses showed that infiltrating monocytes expressed Slit2 in the perivascular and adventitial tissues of injured arteries 1 and 3 days postangioplasty. In addition, recombinant full-length Slit2 and Slit2-N/1118, an N-terminal fragment of Slit2, inhibited stromal cell-derived factor 1-mediated migration of circulating rat peripheral blood mononuclear cells. In summary, adventitial activation of CAM genes and neutrophil infiltration preceded

  5. Generation of Electron Bessel Beams with Nondiffractive Spreading by a Nanofabricated Annular Slit

    NASA Astrophysics Data System (ADS)

    Saitoh, Koh; Hirakawa, Kazuma; Nambu, Hiroki; Tanaka, Nobuo; Uchida, Masaya

    2016-04-01

    The shaping of a wavefront of free electrons has been experimentally realized very recently. We report the generation of an electron Bessel beam using a nanofabricated annular slit. We directly observe that electron Bessel beams propagate while maintaining a narrow beam width over a long propagation distance. In addition, we experimentally verify the self-healing property of these electron beams, which can reconstruct their shape after passing an obstacle. The experimental results are compared with simulation results of the propagation including a hexagonal slit. The present technique of electron Bessel beam generation can be used to develop a novel electron-beam-shaping, an atomic manipulation technique, and a new electron microscopy.

  6. Theoretical investigation of maintaining the boundary layer of revolution laminar using suction slits in incompressible flow

    NASA Technical Reports Server (NTRS)

    Thiede, P.

    1978-01-01

    The transition of the laminar boundary layer into the turbulent state, which results in an increased drag, can be avoided by sucking of the boundary layer particles near the wall. The technically-interesting case of sucking the particles using individual slits is investigated for bodies of revolution in incompressible flow. The results of the variational calculations show that there is an optimum suction height, where the slot separations are maximum. Combined with favorable shaping of the body, it is possible to keep the boundary layer over bodies of revolution laminar at high Reynolds numbers using relatively few suction slits and small amounts of suction flow.

  7. Use of the focusing multi-slit ion optical system at RUssian Diagnostic Injector (RUDI)

    SciTech Connect

    Listopad, A.; Davydenko, V.; Ivanov, A.; Mishagin, V.; Savkin, V.; Shulzhenko, G.; Coenen, J.; Schweer, B.; Uhlemann, R.

    2012-02-15

    The upgrade of the diagnostic neutral beam injector RUDI in 2010 was performed to increase the beam density at the focal plane in accordance with the requirements of charge-exchange recombination spectroscopy diagnostics. A new focusing ion-optical system (IOS) with slit beamlets and an enlarged aperture was optimized for 50% higher nominal beam current and reduced angular divergence with respect to the previous multi-aperture IOS version. The upgraded injector provides the beam current up to 3 A, the measured beam divergence in the direction along the slits is 0.35 deg. Additionally, the plasma generator was modified to extend the beam pulse to 8 s.

  8. Focusing and directional beaming effects of airborne sound through a planar lens with zigzag slits

    SciTech Connect

    Tang, Kun; Qiu, Chunyin Lu, Jiuyang; Ke, Manzhu; Liu, Zhengyou

    2015-01-14

    Based on the Huygens-Fresnel principle, we design a planar lens to efficiently realize the interconversion between the point-like sound source and Gaussian beam in ambient air. The lens is constructed by a planar plate perforated elaborately with a nonuniform array of zigzag slits, where the slit exits act as subwavelength-sized secondary sources carrying desired sound responses. The experiments operated at audible regime agree well with the theoretical predictions. This compact device could be useful in daily life applications, such as for medical and detection purposes.

  9. Preliminary design of a multi-slit image slicer for EST

    NASA Astrophysics Data System (ADS)

    Calcines, A.; López, R. L.; Collados, M.

    2012-09-01

    Integral field spectroscopy is a modern technique used in Astronomy to obtain simultaneous spectral information of all points in a bidimensional field of view. This communication presents the preliminary design of a multi-slit image slicer to be coupled to the spectrographs of the 4 meters aperture European Solar Telescope. This integral field unit will provide the observation of an 80 arcsec2 field of view, rearranged into 8 slits of 200 arcsec length by 0.05 arcsec width. Different optical design alternatives with diffraction limited optical quality, as well as the design of a prototype for the GREGOR solar telescope, are presented.

  10. Near-field surface plasmon effects on Au-double-slit diffraction for polychromatic light

    PubMed Central

    2014-01-01

    The surface plasmon effects on near-field diffraction for polychromatic light are studied. An Au-double-slit is used as the model and Fresnel integral is employed to perform the theoretic analysis. The results are illustrated with numerical examples and they show that, compared with the normal double-slit, the plasmon effect changes the spectral shift from redshift to blueshift and also enhances the intensity peak. This effect can be used in optical data transmission or specific spectral selectors. PMID:25386100

  11. Interference from a nonlocal double-slit through one-photon process.

    PubMed

    Gan, Shu; Zhang, Su-Heng; Xiong, Jun; Wang, Kaige

    2009-12-21

    In this paper, we report an interference experiment in which a spatially incoherent light source illuminates two spatially separated apertures, whose superposition at the same place forms a double-slit. The experimental result exhibits a well-defined interference fringe solely through intensity measurements, in agreement with the theoretical analysis by means of the first-order spatial interference of the incoherent light. Consequently, the nonlocal double-slit interference with thermal light should be attributed to the first-order spatial correlation of incoherent field.

  12. Radical-ion-pair reactions are the biochemical equivalent of the optical double-slit experiment.

    PubMed

    Kominis, Iannis K

    2011-05-01

    Radical-ion-pair reactions were recently shown to represent a rich biophysical laboratory for the application of quantum measurement theory methods and concepts. Here we show that radical-ion-pair reactions essentially form a nonlinear biochemical double-slit interferometer. Quantum coherence effects are visible when "which-path" information is limited, and the incoherent limit is approached when measurement-induced decoherence sets in. Based on this analogy with the optical double-slit experiment we derive and elaborate on the fundamental master equation of spin-selective radical-ion-pair reactions that covers the continuous range from complete incoherence to maximum singlet-triplet coherence.

  13. Origin of the Norton-type wave scattered by a subwavelength metallic slit

    NASA Astrophysics Data System (ADS)

    Le Perchec, Jérôme

    2015-10-01

    We clarify analytically and numerically the physical origin and the behavior of the Norton field scattered by a narrow slit, at optical frequencies. This apparent surface field, which comes in addition to the surface plasmon-polariton and classic cylindrical light waves, features its own radiation lobe associated with oscillating induced currents that spread over both horizontal metallic parts forming the slit. Theory is given taking into account the finite size of the aperture and is illustrated with materials such as gold and amorphous silicon in different spectral regions.

  14. Rapid screening and characterization of drug metabolites using multiple ion monitoring dependent product ion scan and postacquisition data mining on a hybrid triple quadrupole-linear ion trap mass spectrometer.

    PubMed

    Yao, Ming; Ma, Li; Duchoslav, Eva; Zhu, Mingshe

    2009-06-01

    Multiple ion monitoring (MIM)-dependent acquisition with a triple quadrupole-linear ion trap mass spectrometer (Q-trap) was previously developed for drug metabolite profiling. In the analysis, multiple predicted metabolite ions are monitored in both Q1 and Q3 regardless of their fragmentations. The collision energy in Q2 is set to a low value to minimize fragmentation. Once an expected metabolite is detected by MIM, enhanced product ion (EPI) spectral acquisition of the metabolite is triggered. To analyze in vitro metabolites, MIM-EPI retains the sensitivity and selectivity similar to that of multiple reaction monitoring (MRM)-EPI in the analysis of in vitro metabolites. Here we present an improved approach utilizing MIM-EPI for data acquisition and multiple data mining techniques for detection of metabolite ions and recovery of their MS/MS spectra. The postacquisition data processing tools included extracted ion chromatographic analysis, product ion filtering and neutral loss filtering. The effectiveness of this approach was evaluated by analyzing oxidative metabolites of indinavir and glutathione (GSH) conjugates of clozapine and 4-ethylphenol in liver microsome incubations. Results showed that the MIM-EPI-based data mining approach allowed for comprehensive detection of metabolites based on predicted protonated molecules, product ions or neutral losses without predetermination of the parent drug MS/MS spectra. Additionally, it enabled metabolite detection and MS/MS acquisition in a single injection. This approach is potentially useful in high-throughout screening of metabolic soft spots and reactive metabolites at the drug discovery stage.

  15. Slit2 and netrin 1 act synergistically as adhesive cues to generate tubular bi-layers during ductal morphogenesis.

    PubMed

    Strickland, Phyllis; Shin, Grace C; Plump, Andrew; Tessier-Lavigne, Marc; Hinck, Lindsay

    2006-03-01

    Development of many organs, including the mammary gland, involves ductal morphogenesis. Mammary ducts are bi-layered tubular structures comprising an outer layer of cap/myoepithelial cells (MECs) and an inner layer of luminal epithelial cells (LECs). Slit2 is expressed by cells in both layers, with secreted SLIT2 broadly distributed throughout the epithelial compartment. By contrast, Robo1 is expressed specifically by cap/MECs. Loss-of-function mutations in Slit2 and Robo1 yield similar phenotypes, characterized by disorganized end buds (EBs) reminiscent of those present in Ntn1(-/-) glands, suggesting that SLIT2 and NTN1 function in concert during mammary development. Analysis of Slit2(-/-);Ntn1(-/-) glands demonstrates an enhanced phenotype that extends through the ducts and is characterized by separated cell layers and occluded lumens. Aggregation assays show that Slit2(-/-);Ntn1(-/-) cells, in contrast to wild-type cells, do not form bi-layered organoids, a defect rescued by addition of SLIT2. NTN1 has no effect alone, but synergistically enhances this rescue. Thus, our data establish a novel role for SLIT2 as an adhesive cue, acting in parallel with NTN1 to generate cell boundaries along ducts during bi-layered tube formation.

  16. SLIT2 attenuation during lung cancer progression deregulates beta-catenin and E-cadherin and associates with poor prognosis.

    PubMed

    Tseng, Ruo-Chia; Lee, Shih-Hua; Hsu, Han-Shui; Chen, Ben-Han; Tsai, Wan-Ching; Tzao, Ching; Wang, Yi-Ching

    2010-01-15

    Chromosome 4p15.3 is frequently deleted in late-stage lung cancer. We investigated the significance of the SLIT2 gene located in this region to lung cancer progression. SLIT2 encodes an extracellular glycoprotein that can suppress breast cancer by regulating beta-catenin. In this study, we examined alterations in the structure or expression of SLIT2, its receptor ROBO1, and beta-catenin, along with the AKT/glycogen synthase kinase 3beta (GSK3beta)/beta-transducin repeat-containing protein (betaTrCP) pathway in lung cancer cell lines and patients. Low SLIT2 expression correlated with an upward trend of pathological stage and poorer survival in lung cancer patients. Importantly, SLIT2, betaTrCP, and beta-catenin expression levels predicted postoperative recurrence of lung cancer in patients. Stimulating SLIT2 expression by various methods increased the level of E-cadherin caused by attenuation of its transcriptional repressor SNAI1. Conversely, knocking down SLIT2 expression increased cell migration and reduced cell adhesion through coordinated deregulation of beta-catenin and E-cadherin/SNAI1 in the AKT/GSK3beta/betaTrCP pathway. Our findings indicate that SLIT2 suppresses lung cancer progression, defining it as a novel "theranostic" factor with potential as a therapeutic target and prognostic predictor in lung cancer. Cancer Res; 70(2); 543-51.

  17. A Slit/miR-218/Robo regulatory loop is required during heart tube formation in zebrafish.

    PubMed

    Fish, Jason E; Wythe, Joshua D; Xiao, Tong; Bruneau, Benoit G; Stainier, Didier Y R; Srivastava, Deepak; Woo, Stephanie

    2011-04-01

    Members of the Slit family of secreted ligands interact with Roundabout (Robo) receptors to provide guidance cues for many cell types. For example, Slit/Robo signaling elicits repulsion of axons during neural development, whereas in endothelial cells this pathway inhibits or promotes angiogenesis depending on the cellular context. Here, we show that miR-218 is intronically encoded in slit2 and slit3 and that it suppresses Robo1 and Robo2 expression. Our data indicate that miR-218 and multiple Slit/Robo signaling components are required for heart tube formation in zebrafish and that this network modulates the previously unappreciated function of Vegf signaling in this process. These findings suggest a new paradigm for microRNA-based control of ligand-receptor interactions and provide evidence for a novel signaling pathway regulating vertebrate heart tube assembly.

  18. Tissue non-linearity.

    PubMed

    Duck, F

    2010-01-01

    The propagation of acoustic waves is a fundamentally non-linear process, and only waves with infinitesimally small amplitudes may be described by linear expressions. In practice, all ultrasound propagation is associated with a progressive distortion in the acoustic waveform and the generation of frequency harmonics. At the frequencies and amplitudes used for medical diagnostic scanning, the waveform distortion can result in the formation of acoustic shocks, excess deposition of energy, and acoustic saturation. These effects occur most strongly when ultrasound propagates within liquids with comparatively low acoustic attenuation, such as water, amniotic fluid, or urine. Attenuation by soft tissues limits but does not extinguish these non-linear effects. Harmonics may be used to create tissue harmonic images. These offer improvements over conventional B-mode images in spatial resolution and, more significantly, in the suppression of acoustic clutter and side-lobe artefacts. The quantity B/A has promise as a parameter for tissue characterization, but methods for imaging B/A have shown only limited success. Standard methods for the prediction of tissue in-situ exposure from acoustic measurements in water, whether for regulatory purposes, for safety assessment, or for planning therapeutic regimes, may be in error because of unaccounted non-linear losses. Biological effects mechanisms are altered by finite-amplitude effects. PMID:20349813

  19. Combining Peyton's four-step approach and Gagne's instructional model in teaching slit-lamp examination.

    PubMed

    Ng, Jia Yu

    2014-12-01

    Developing skills in performing basic slit-lamp biomicroscopy is an important element of the ophthalmology undergraduate curriculum. As a doctor working in an ophthalmology department, I often provide slit-lamp teaching for medical students. This paper describes a lesson plan for this technique using Gagne's nine events of instruction. The presented lesson plan is a combination of Gagne's nine events of instruction and Peyton's four-step approach. Gagne's nine events of instruction correlate with and address the mental conditions of learning when adult learners are presented with various stimuli. Peyton's four-step approach is a model for teaching practical skills that consists of demonstration, deconstruction, explanation, and performance. This article describes a slit-lamp biomicroscopy teaching session using Gagne's nine events of instruction. Each step is carefully elaborated with relevant activities to suit learners with various learning styles. Peyton's approach is used to teach the actual skill. This lesson plan is particularly relevant for tutors designing slit-lamp biomicroscopy teaching for undergraduate students, foundation doctors, general practitioners and emergency department staff. Ultimately, this lesson plan also serves as a model that is applicable for acquiring many other practical skills. The flexible adoption of Gagne's nine events of instruction in combination with other teaching models helps in the planning of effective teaching sessions.

  20. A double-slit experiment for non-classical interference effects in decision making.

    PubMed

    La Mura, Pierfrancesco

    2014-01-01

    We discuss the possible nature and role of non-physical entanglement, and the classical vs. non-classical interface, in models of human decision-making. We also introduce an experimental setting designed after the double-slit experiment in physics, and discuss how it could be used to discriminate between classical and non-classical interference effects in human decisions. PMID:24259289

  1. An analytical algorithm for skew-slit imaging geometry with nonuniform attenuation correction

    SciTech Connect

    Huang Qiu; Zeng, Gengsheng L.

    2006-04-15

    The pinhole collimator is currently the collimator of choice in small animal single photon emission computed tomography (SPECT) imaging because it can provide high spatial resolution and reasonable sensitivity when the animal is placed very close to the pinhole. It is well known that if the collimator rotates around the object (e.g., a small animal) in a circular orbit to form a cone-beam imaging geometry with a planar trajectory, the acquired data are not sufficient for an exact artifact-free image reconstruction. In this paper a novel skew-slit collimator is mounted instead of the pinhole collimator in order to significantly reduce the image artifacts caused by the geometry. The skew-slit imaging geometry is a more generalized version of the pinhole imaging geometry. The multiple pinhole geometry can also be extended to the multiple-skew-slit geometry. An analytical algorithm for image reconstruction based on the tilted fan-beam inversion is developed with nonuniform attenuation compensation. Numerical simulation shows that the axial artifacts are evidently suppressed in the skew-slit images compared to the pinhole images and the attenuation correction is effective.

  2. Induction of intestinal stem cells by R-spondin 1 and Slit2 augments chemoradioprotection.

    PubMed

    Zhou, Wei-Jie; Geng, Zhen H; Spence, Jason R; Geng, Jian-Guo

    2013-09-01

    Cancer research has been rightly and successfully focused on prevention, early detection, and identification of specific molecular targets that distinguish the malignant cells from the neighbouring benign cells. However, reducing lethal tissue injury caused by intensive chemoradiotherapy during treatment of late-stage metastatic cancers remains a key clinical challenge. Here we tested whether the induction of adult stem cells could repair chemoradiation-induced tissue injury and prolong overall survival in mice. We found that intestinal stem cells (ISCs) expressed Slit2 and its single-span transmembrane cell-surface receptor roundabout 1 (Robo1). Partial genetic deletion of Robo1 decreased ISC numbers and caused villus hypotrophy, whereas a Slit2 transgene increased ISC numbers and triggered villus hypertrophy. During lethal dosages of chemoradiation, administering a short pulse of R-spondin 1 (Rspo1; a Wnt agonist) plus Slit2 reduced ISC loss, mitigated gut impairment and protected animals from death, without concomitantly decreasing tumour sensitivity to chemotherapy. Therefore Rspo1 and Slit2 may act as therapeutic adjuvants to enhance host tolerance to aggressive chemoradiotherapy for eradicating metastatic cancers.

  3. Endocannabinoids modulate cortical development by configuring Slit2/Robo1 signalling.

    PubMed

    Alpár, Alán; Tortoriello, Giuseppe; Calvigioni, Daniela; Niphakis, Micah J; Milenkovic, Ivan; Bakker, Joanne; Cameron, Gary A; Hanics, János; Morris, Claudia V; Fuzik, János; Kovacs, Gabor G; Cravatt, Benjamin F; Parnavelas, John G; Andrews, William D; Hurd, Yasmin L; Keimpema, Erik; Harkany, Tibor

    2014-07-17

    Local environmental cues are indispensable for axonal growth and guidance during brain circuit formation. Here, we combine genetic and pharmacological tools, as well as systems neuroanatomy in human fetuses and mouse models, to study the role of endocannabinoid and Slit/Robo signalling in axonal growth. We show that excess 2-arachidonoylglycerol, an endocannabinoid affecting directional axonal growth, triggers corpus callosum enlargement due to the errant CB1 cannabinoid receptor-containing corticofugal axon spreading. This phenotype mechanistically relies on the premature differentiation and end-feet proliferation of CB2R-expressing oligodendrocytes. We further show the dependence of both axonal Robo1 positioning and oligodendroglial Slit2 production on cell-type-specific cannabinoid receptor activation. Accordingly, Robo1 and/or Slit2 manipulation limits endocannabinoid modulation of axon guidance. We conclude that endocannabinoids can configure focal Slit2/Robo1 signalling to modulate directional axonal growth, which may provide a basis for understanding impaired brain wiring associated with metabolic deficits and prenatal drug exposure.

  4. Slit2 as a β-catenin/Ctnnb1-dependent retrograde signal for presynaptic differentiation.

    PubMed

    Wu, Haitao; Barik, Arnab; Lu, Yisheng; Shen, Chengyong; Bowman, Andrew; Li, Lei; Sathyamurthy, Anupama; Lin, Thiri W; Xiong, Wen-Cheng; Mei, Lin

    2015-07-10

    Neuromuscular junction formation requires proper interaction between motoneurons and muscle cells. β-Catenin (Ctnnb1) in muscle is critical for motoneuron differentiation; however, little is known about the relevant retrograde signal. In this paper, we dissected which functions of muscle Ctnnb1 are critical by an in vivo transgenic approach. We show that Ctnnb1 mutant without the transactivation domain was unable to rescue presynaptic deficits of Ctnnb1 mutation, indicating the involvement of transcription regulation. On the other hand, the cell-adhesion function of Ctnnb1 is dispensable. We screened for proteins that may serve as a Ctnnb1-directed retrograde factor and identified Slit2. Transgenic expression of Slit2 specifically in the muscle was able to diminish presynaptic deficits by Ctnnb1 mutation in mice. Slit2 immobilized on beads was able to induce synaptophysin puncta in axons of spinal cord explants. Together, these observations suggest that Slit2 serves as a factor utilized by muscle Ctnnb1 to direct presynaptic differentiation.

  5. Dynamic expression of the Robo ligand Slit2 in bone marrow cell populations.

    PubMed

    Smith-Berdan, Stephanie; Schepers, Koen; Ly, Alan; Passegué, Emmanuelle; Forsberg, E Camilla

    2012-02-15

    The bone marrow (BM) niche is essential for lifelong hematopoietic stem cell (HSC) maintenance, proliferation and differentiation. Several BM cell types, including osteoblast lineage cells (OBC), mesenchymal stem cells (MSC) and endothelial cells (EC) have been implicated in supporting HSC location and function, but the relative importance of these cell types and their secreted ligands remain controversial. We recently found that the cell surface receptors Robo4 and CXCR4 cooperate to localize HSC to BM niches. We hypothesized that Slit2, a putative ligand for Robo4, cooperates with the CXCR4 ligand SDF1 to direct HSC to specific BM niche sites. Here, we have isolated OBC, MSC and EC by flow cytometry and determined their frequency within the bone marrow and the relative mRNA levels of Slit2, SDF1 and Robo4. We found that expression of Slit2 and SDF1 were dynamically regulated in MSC and OBC-like populations following radiation, while Robo4 expression was restricted to EC. Radiation also significantly affected the cellularity and frequency of both the non-adherent and adherent cells within the BM stroma. These data support a physiological role for Slit2 in regulating the dynamic function of Robo-expressing cells within BM niches at steady state and following radiation.

  6. Endocannabinoids modulate cortical development by configuring Slit2/Robo1 signaling

    PubMed Central

    Alpár, Alán; Tortoriello, Giuseppe; Calvigioni, Daniela; Niphakis, Micah J; Milenkovic, Ivan; Bakker, Joanne; Cameron, Gary A; Hanics, János; Morris, Claudia V; Fuzik, János; Kovacs, Gabor G; Cravatt, Benjamin F; Parnavelas, John G; Andrews, William D; Hurd, Yasmin L; Keimpema, Erik; Harkany, Tibor

    2014-01-01

    Local environmental cues are indispensable for axonal growth and guidance during brain circuit formation. Here, we combine genetic and pharmacological tools, as well as systems neuroanatomy in human fetuses and mouse models, to study the role of endocannabinoid and Slit/Robo signaling in axonal growth. We show that excess 2-arachidonoylglycerol, an endocannabinoid affecting directional axonal growth, triggers corpus callosum enlargement due to errant CB1 cannabinoid receptor (CB1R)-containing corticofugal axon spreading. This phenotype mechanistically relies on the premature differentiation and end-feet proliferation of CB2R-expressing oligodendrocytes. We further show the dependence of both axonal Robo1 positioning and oligodendroglial Slit2 production on cell-type specific cannabinoid receptor activation. Accordingly, Robo1 and/or Slit2 manipulation limits endocannabinoid modulation of axon guidance. We conclude that endocannabinoids can configure focal Slit2/Robo1 signaling to modulate directional axonal growth, which may provide a basis for understanding impaired brain wiring associated with metabolic deficits and prenatal drug exposure. PMID:25030704

  7. Single-Slit Diffraction Pattern of a Thermal Atomic Potassium Beam

    ERIC Educational Resources Information Center

    Leavitt, John A.; Bills, Francis A.

    1969-01-01

    The diffraction of a full thermal atomic potassium beam by a single slit was observed. Four experimental diffraction patterns were compared with that predicted by de Brogtie's hypothesis and simple scalar Fresnel diffraction theory. Possible reasons for the differences were discussed. (LC)

  8. A dielectric slit die for in-line monitoring of polymer compounding

    NASA Astrophysics Data System (ADS)

    Bur, Anthony J.; Roth, Steven C.; Lee, Yu-Hsin; McBrearty, Michael

    2004-04-01

    The dielectric slit die is an instrument that is designed to measure electrical, rheological, ultrasonics, optical, and other properties of a flowing liquid. In one application, it is connected to the exit of an extruder, pump or mixing machine that passes liquefied material such as molten plastic, solvents, slurries, colloidal suspensions, and foodstuffs into the sensing region of the slit-shaped die. Dielectric sensing is the primary element of the slit die, but in addition to the dielectric sensor, the die contains other sensing devices such as pressure, optical fiber, and ultrasonic sensors that simultaneously yield an array of materials property data. The slit die has a flexible design that permits interchangeability among sensors and sensor positions. The design also allows for the placement of additional sensors and instrumentation ports that expand the potential data package obtained. To demonstrate sensor operation, we present data from the extrusion and compounding of a polymer/clay nanocomposite. An analysis of the dielectric data involves a nonlinear fitting procedure that takes into account effects due to electrode polarization and dc conductivity. Light transmission through a filled polymer is analyzed in terms of a Beer's law attenuation coefficient.

  9. Assembly of lamina-specific neuronal connections by Slit bound to type IV Collagen

    PubMed Central

    Xiao, Tong; Staub, Wendy; Robles, Estuardo; Gosse, Nathan J.; Cole, Gregory J.; Baier, Herwig

    2011-01-01

    The mechanisms that generate specific neuronal connections in the brain are under intense investigation. In zebrafish, retinal ganglion cells project their axons into at least six layers within the neuropil of the midbrain tectum. Each axon elaborates a single, planar arbor in one of the target layers and forms synapses onto the dendrites of tectal neurons. We show that the laminar specificity of retinotectal connections does not depend on self-sorting interactions among RGC axons. Rather, tectum-derived Slit1, signaling through axonal Robo2, guides neurites to their target layer. Genetic and biochemical studies indicate that Slit binds to Dragnet (Col4a5), a type IV Collagen, which forms the basement membrane on the surface of the tectum. We further show that radial glial endfeet are required for the basement-membrane anchoring of Slit. We propose that Slit1 signaling, perhaps in the form of a superficial-to-deep gradient, presents laminar positional cues to ingrowing retinal axons. PMID:21729787

  10. Ultra-small and broadband polarization splitters based on double-slit interference

    NASA Astrophysics Data System (ADS)

    Sun, Chengwei; Li, Hongyun; Gong, Qihuang; Chen, Jianjun

    2016-03-01

    An ultra-small and broadband polarization splitter is numerically and experimentally demonstrated based on the double-slit interference in a polymer-film-coated double-slit structure. The hybrid slab waveguide (air-polymer-Au) supports both the transverse-magnetic and transverse-electric modes. The incident beam from the back side can excite these two guided modes of orthogonally polarized states in the hybrid structure. By exploiting the difference slit widths and the large mode birefringence, these two guided modes propagate to the opposite directions along the front metal surface. Moreover, the short interference length broadens the operation bandwidth. Experimentally, a polarization splitter with a lateral dimension of only about 1.6 μm and an operation bandwidth of 50 nm is realized. By designing the double-slit structure in a hybrid strip waveguide, the device dimension can be significant downscaled to about 0.3 × 1.3 μm2. Such an ultra-small and broadband polarization splitter may find important applications in the integrated photonic circuits.

  11. A double-slit experiment for non-classical interference effects in decision making.

    PubMed

    La Mura, Pierfrancesco

    2014-01-01

    We discuss the possible nature and role of non-physical entanglement, and the classical vs. non-classical interface, in models of human decision-making. We also introduce an experimental setting designed after the double-slit experiment in physics, and discuss how it could be used to discriminate between classical and non-classical interference effects in human decisions.

  12. Young's double-slit experiment with single photons and quantum eraser

    NASA Astrophysics Data System (ADS)

    Rueckner, Wolfgang; Peidle, Joseph

    2013-12-01

    An apparatus for a double-slit interference experiment in the single-photon regime is described. The apparatus includes a which-path marker that destroys the interference as well as a quantum eraser that restores it. We present data taken with several light sources, coherent and incoherent and discuss the efficacy of these as sources of single photons.

  13. Probing Pre- and In-service Physics Teachers' Knowledge Using the Double-Slit Thought Experiment

    NASA Astrophysics Data System (ADS)

    Asikainen, Mervi A.; Hirvonen, Pekka E.

    2014-09-01

    This study describes the use of the double-slit thought experiment as a diagnostic tool for probing physics teachers' understanding. A total of 9 pre-service teachers and 18 in-service teachers with a variety of different experience in modern physics teaching at the upper secondary level responded in a paper-and-pencil test and three of these teachers were interviewed. The results showed that the physics teachers' thought experiments with classical particles, light, and electrons were often partial. Many teachers also suffered a lack of the basic ideas and principles of physics, which probably hindered thought experimenting. In particular, understanding the ontological nature of classical particles, light and electrons seemed to be essential in performing the double-slit experiment in an appropriate way. However, the in-service physics teachers who had teaching experience in modern physics were more prepared for the double-slit thought experiment than the pre-service teachers. The results suggest that both thought experiments and the double-slit experiment should be given more weight in physics teacher education, even if experience in modern physics teaching at upper secondary school seems to some extent to develop teachers' abilities.

  14. Investigation of Conceptual Change about Double-Slit Interference in Secondary School Physics

    ERIC Educational Resources Information Center

    Kocakulah, Mustafa Sabri; Kural, Mehmet

    2010-01-01

    In this study, whether or not constructivist teaching of double-slit interference of light has a positive effect on the secondary school students' conceptual change is examined. An achievement test, a conceptual understanding test and semi-structured interviews were used as data collection tools in this mixed methods research. Experimental group…

  15. Feynman Path Integral Approach to Electron Diffraction for One and Two Slits: Analytical Results

    ERIC Educational Resources Information Center

    Beau, Mathieu

    2012-01-01

    In this paper we present an analytic solution of the famous problem of diffraction and interference of electrons through one and two slits (for simplicity, only the one-dimensional case is considered). In addition to exact formulae, various approximations of the electron distribution are shown which facilitate the interpretation of the results.…

  16. Slit2 as a β-catenin/Ctnnb1-dependent retrograde signal for presynaptic differentiation

    PubMed Central

    Wu, Haitao; Barik, Arnab; Lu, Yisheng; Shen, Chengyong; Bowman, Andrew; Li, Lei; Sathyamurthy, Anupama; Lin, Thiri W; Xiong, Wen-Cheng; Mei, Lin

    2015-01-01

    Neuromuscular junction formation requires proper interaction between motoneurons and muscle cells. β-Catenin (Ctnnb1) in muscle is critical for motoneuron differentiation; however, little is known about the relevant retrograde signal. In this paper, we dissected which functions of muscle Ctnnb1 are critical by an in vivo transgenic approach. We show that Ctnnb1 mutant without the transactivation domain was unable to rescue presynaptic deficits of Ctnnb1 mutation, indicating the involvement of transcription regulation. On the other hand, the cell-adhesion function of Ctnnb1 is dispensable. We screened for proteins that may serve as a Ctnnb1-directed retrograde factor and identified Slit2. Transgenic expression of Slit2 specifically in the muscle was able to diminish presynaptic deficits by Ctnnb1 mutation in mice. Slit2 immobilized on beads was able to induce synaptophysin puncta in axons of spinal cord explants. Together, these observations suggest that Slit2 serves as a factor utilized by muscle Ctnnb1 to direct presynaptic differentiation. DOI: http://dx.doi.org/10.7554/eLife.07266.001 PMID:26159615

  17. Slit/Robo signaling modulates the proliferation of central nervous system progenitors.

    PubMed

    Borrell, Víctor; Cárdenas, Adrián; Ciceri, Gabriele; Galcerán, Joan; Flames, Nuria; Pla, Ramón; Nóbrega-Pereira, Sandrina; García-Frigola, Cristina; Peregrín, Sandra; Zhao, Zhen; Ma, Le; Tessier-Lavigne, Marc; Marín, Oscar

    2012-10-18

    Neurogenesis relies on a delicate balance between progenitor maintenance and neuronal production. Progenitors divide symmetrically to increase the pool of dividing cells. Subsequently, they divide asymmetrically to self-renew and produce new neurons or, in some brain regions, intermediate progenitor cells (IPCs). Here we report that central nervous system progenitors express Robo1 and Robo2, receptors for Slit proteins that regulate axon guidance, and that absence of these receptors or their ligands leads to loss of ventricular mitoses. Conversely, production of IPCs is enhanced in Robo1/2 and Slit1/2 mutants, suggesting that Slit/Robo signaling modulates the transition between primary and intermediate progenitors. Unexpectedly, these defects do not lead to transient overproduction of neurons, probably because supernumerary IPCs fail to detach from the ventricular lining and cycle very slowly. At the molecular level, the role of Slit/Robo in progenitor cells involves transcriptional activation of the Notch effector Hes1. These findings demonstrate that Robo signaling modulates progenitor cell dynamics in the developing brain. PMID:23083737

  18. Single- and double-slit collimating effects on fast-atom diffraction spectra

    NASA Astrophysics Data System (ADS)

    Gravielle, M. S.; Miraglia, J. E.

    2016-09-01

    Diffraction patterns produced by fast He atoms grazingly impinging on a LiF(0 0 1) surface are investigated focusing on the influence of the beam collimation. Single- and double-slit collimating devices situated in front of the beam source are considered. To describe the scattering process we use the Surface Initial Value Representation (SIVR) approximation, which is a semi-quantum approach that incorporates a realistic description of the initial wave packet in terms of the collimating parameters. Our initial wave-packet model is based on the Van Cittert-Zernike theorem. For a single-slit collimation the width of the collimating aperture controls the shape of the azimuthal angle distribution, making different interference mechanisms visible, while the length of the slit affects the polar angle distribution. Additionally, we found that by means of a double-slit collimation it might be possible to obtain a wide polar angle distribution, which is associated with a large spread of the initial momentum perpendicular to the surface, derived from the uncertainty principle. It might be used as a simple way to probe the surface potential for different normal energies.

  19. The Time-Dependent Sensitivity of the MAMA and CCD Long-Slit Gratings

    NASA Astrophysics Data System (ADS)

    Holland, Stephen T.; Aloisi, Alessandra; Bostroem, Azalee; Oliveria, Cristina; Proffitt, Charles

    2014-12-01

    We present the results of observing flux standard stars used to determine trends in the sensitivities of the five STIS low-resolution, long-slit gratings between 1997 and 2013. Also, the assumption that the sensitivity trends for the medium-resolution and echelle gratings are the same as those for the corresponding low-resolution gratings is tested.

  20. Development of Flight Slit-Jaw Optics for Chromospheric Lyman-Alpha SpectroPolarimeter

    NASA Technical Reports Server (NTRS)

    Kubo, Masahito; Suematsu, Yoshinori; Kano, Ryohei; Bando, Takamasa; Hara, Hirohisa; Narukage, Noriyuki; Katsukawa, Yukio; Ishikawa, Ryoko; Ishikawa, Shin-nosuke; Kobiki, Toshihiko; Tsuneta, Saku; Kobayashi, Ken; Winebarger, Amy; Takeyama, Norihide; Kanai, Yoshikazu; Sakakibara, Yoshiko

    2015-01-01

    In sounding rocket experiment CLASP, I have placed a slit a mirror-finished around the focal point of the telescope. The light reflected by the mirror surface surrounding the slit is then imaged in Slit-jaw optical system, to obtain the a-ray Lyman secondary image. This image, not only to use the real-time image in rocket flight rocket oriented direction selection, and also used as a scientific data showing the spatial structure of the Lyman alpha emission line intensity distribution and solar chromosphere around the observation area of the polarimetric spectroscope. Slit-jaw optical system is a two off-axis mirror unit part including a parabolic mirror and folding mirror, Lyman alpha transmission filter, the optical system magnification 1x consisting camera. The camera is supplied from the United States, and the other was carried out fabrication and testing in all the Japanese side. Slit-jaw optical system, it is difficult to access the structure, it is necessary to install the low place clearance. Therefore, influence the optical performance, the fine adjustment is necessary optical elements are collectively in the form of the mirror unit. On the other hand, due to the alignment of the solar sensor in the US launch site, must be removed once the Lyman alpha transmission filter holder including a filter has a different part from the mirror unit. In order to make the structure simple, stray light measures Aru to concentrate around Lyman alpha transmission filter. To overcome the difficulties of performing optical alignment in Lyman alpha wavelength absorbed by the atmosphere, it was planned 'following four steps in order to reduce standing time alignment me. 1. is measured in advance refractive index at Lyman alpha wavelength of Lyman alpha transmission filter (121.567nm), to prepare a visible light Firuwo having the same optical path length in the visible light (630nm).2. The mirror structure CLASP before mounting unit standing, dummy slit and camera standing

  1. Development of Flight Slit-Jaw Optics for Chromospheric Lyman-Alpha SpectroPolarimeter

    NASA Technical Reports Server (NTRS)

    Kubo, Masahito; Suematsu, Yoshinori; Kano, Ryohei; Bando, Takamasa; Hara, Hirohisa; Narukage, Noriyuki; Katsukawa, Yukio; Ishikawa, Ryoko; Ishikawa, Shin-nosuke; Kobiki, Toshihiko; Tsuneta, Saku; Kobayashi, Ken; Winebarger, Amy; Takeyama, Norihide; Kanai, Yoshikazu; Sakakibara, Yoshiko

    2015-01-01

    In sounding rocket experiment CLASP, I have placed a slit a mirror-finished around the focal point of the telescope. The light reflected by the mirror surface surrounding the slit is then imaged in Slit-jaw optical system, to obtain the alpha-ray Lyman secondary image. This image, not only to use the real-time image in rocket flight rocket oriented direction selection, and also used as a scientific data showing the spatial structure of the Lyman alpha emission line intensity distribution and solar chromosphere around the observation area of the polarimetric spectroscope. Slit-jaw optical system is a two off-axis mirror unit part including a parabolic mirror and folding mirror, Lyman alpha transmission filter, the optical system magnification 1x consisting camera. The camera is supplied from the United States, and the other was carried out fabrication and testing in all the Japanese side. Slit-jaw optical system, it is difficult to access the structure, it is necessary to install the low place clearance. Therefore, influence the optical performance, the fine adjustment is necessary optical elements are collectively in the form of the mirror unit. On the other hand, due to the alignment of the solar sensor in the US launch site, must be removed once the Lyman alpha transmission filter holder including a filter has a different part from the mirror unit. In order to make the structure simple, stray light measures Aru to concentrate around Lyman alpha transmission filter. To overcome the difficulties of performing optical alignment in Lyman alpha wavelength absorbed by the atmosphere, it was planned following four steps in order to reduce standing time alignment me. 1: is measured in advance refractive index at Lyman alpha wavelength of Lyman alpha transmission filter (121.567nm), to prepare a visible light Firuwo having the same optical path length in the visible light (630nm). 2: The mirror structure CLASP before mounting unit standing, dummy slit and camera standing

  2. Loss of expression and promoter methylation of SLIT2 are associated with sessile serrated adenoma formation.

    PubMed

    Beggs, Andrew D; Jones, Angela; Shepherd, Neil; Arnaout, Abed; Finlayson, Caroline; Abulafi, A Muti; Morton, Dion G; Matthews, Glenn M; Hodgson, Shirley V; Tomlinson, Ian P M

    2013-05-01

    Serrated adenomas form a distinct subtype of colorectal pre-malignant lesions that may progress to malignancy along a different molecular pathway than the conventional adenoma-carcinoma pathway. Previous studies have hypothesised that BRAF mutation and promoter hypermethylation plays a role, but the evidence for this is not robust. We aimed to carry out a whole-genome loss of heterozygosity analysis, followed by targeted promoter methylation and expression analysis to identify potential pathways in serrated adenomas. An initial panel of 9 sessile serrated adenomas (SSA) and one TSA were analysed using Illumina Goldengate HumanLinkage panel arrays to ascertain regions of loss of heterozygosity. This was verified via molecular inversion probe analysis and microsatellite analysis of a further 32 samples. Methylation analysis of genes of interest was carried out using methylation specific PCR (verified by pyrosequencing) and immunohistochemistry used to correlate loss of expression of genes of interest. All experiments used adenoma samples and normal tissue samples as control. SSA samples were found on whole-genome analysis to have consistent loss of heterozygosity at 4p15.1-4p15.31, which was not found in the sole TSA, adenomas, or normal tissues. Genes of interest in this region were PDCH7 and SLIT2, and combined MSP/IHC analysis of these genes revealed significant loss of SLIT2 expression associated with promoter methylation of SLIT2. Loss of expression of SLIT2 by promoter hypermethylation and loss of heterozygosity events is significantly associated with serrated adenoma development, and SLIT2 may represent a epimutated tumour suppressor gene according to the Knudson "two hit" hypothesis.

  3. Flow and heat transfer in the wake of a surface-mounted rib with a slit

    NASA Astrophysics Data System (ADS)

    Tariq, Andallib; Panigrahi, P. K.; Muralidhar, K.

    2004-11-01

    An experimental study of flow and heat transfer downstream of a surface-mounted rib with a slit is reported. The open area ratios of the slit rib considered are 10, 20, 30, 40 and 50% with respect to the total projected rib area. Experiments were conducted in a wind tunnel, mostly at a hydraulic diameter based Reynolds number of 32,100. The surface Nusselt number distribution was determined by liquid crystal thermography. Results show that the slit inside the rib enhances heat transfer and reduces pressure penalty, with an optimum performance seen at an open area ratio of 20%. To explain this result, a qualitative picture of the flow field behind the rib was obtained by smoke visualization. Time averages and turbulent statistics of the velocity and temperature fluctuations were measured in detail, using hotwire anemometry and cold wire anemometry respectively. For open area ratios less than 30%, measurements show that the flow through the slit modifies the reattaching shear layer from the top of the rib. The resulting reattachment length is smaller, the peak in Nusselt number is higher, and the average heat transfer from the heated surface is enhanced. For the rib with an open area ratio greater than 40%, the lower portion behaves as an independent small rib with its own reattachment region. Simultaneously, the flow downstream of the upper rectangular part shows characteristics of vortex shedding. Thus, the size of the slit is seen to be an additional parameter that can be used to control heat transfer from the solid surface, in comparison to the solid rib.

  4. Powerful DMD-based light sources with a high throughput virtual slit

    NASA Astrophysics Data System (ADS)

    Hajian, Arsen R.; Gooding, Ed; Gunn, Thomas; Bradbury, Steven

    2016-02-01

    Many DMD-based programmable light sources consist of a white light source and a pair of spectrometers operating in subtractive mode. A DMD between the two spectrometers shapes the delivered spectrum. Since both spectrometers must (1) fit within a small volume, and (2) provide significant spectral resolution, a narrow intermediary slit is required. Another approach is to use a spectrometer designed around a High Throughput Virtual Slit, which enables higher spectral resolution than is achievable with conventional spectroscopy by manipulating the beam profile in pupil space. Conventional imaging spectrograph designs image the entrance slit onto the exit focal plane after dispersing the spectrum. Most often, near 1:1 imaging optics are used in order to optimize both entrance aperture and spectral resolution. This approach limits the spectral resolution to the product of the dispersion and the slit width. Achieving high spectral resolution in a compact instrument necessarily requires a narrow entrance slit, which limits instrumental throughput (étendue). By reshaping the pupil with reflective optics, HTVS-equipped instruments create a tall, narrow image profile at the exit focal plane without altering the NA, typically delivering 5X or better spectral resolution than is achievable with a conventional design. This approach works equally well in DMD-based programmable light sources as in single stage spectrometers. Assuming a 5X improvement in étendue, a 500 W source can be replaced by a 100 W equivalent, creating a cooler, more efficient tunable light source with equal power density over the desired bandwidth without compromising output power.

  5. Automated, Computerized, Feature-Based Phenotype Analysis of Slit Lamp Images of the Mouse Lens

    PubMed Central

    Yuen, Jenny; Li, Yi; Shapiro, Linda G.; Clark, John I.; Arnett, Ernest; Sage, E. Helene; Brinkley, James F.

    2008-01-01

    Longitudinal studies of a variety of transgenic mouse models for lens development can create substantial challenges in database management and analysis. We report a novel, automated, feature-based informatics approach to screening lens phenotypes in a large database of slit lamp images. Digital slit lamp images of normal and abnormal lenses in eyes of wild type (wt), SC1 null and SPARC null transgenic mice were recorded for quantitative evaluation of their structural phenotype. The images were processed to improve the contrast of structural features that corresponded to rings of opacity and fluctuations in scattering intensity in the lenses. Measurable attributes were assigned to the features in the lens images and given as an output vector of 46 dimensions. Characteristic patterns correlated with the structural phenotype of each mutant and wt lens and a statistical fit for each phenotype was defined. The genotype was identified correctly in nearly 85% of the slit lamp images on the basis of an automated computer analysis of the lens structural phenotype. The automated computer algorithm has the potential to evaluate a large database of slit lamp images and distinguish mouse genotypes on the basis of lens phenotypes objectively using a neural network analysis of the structural features observed in the slit lamp images. The neural network approach is a promising technology for objective evaluation of genotype/phenotype relationships based on structural features and light scattering in lenses. Further improvements in the automated method can be expected to simplify and increase the accuracy and efficiency of the feature based analysis of structural phenotypes linked to genetic variation. PMID:18304532

  6. LINEAR ACCELERATOR

    DOEpatents

    Colgate, S.A.

    1958-05-27

    An improvement is presented in linear accelerators for charged particles with respect to the stable focusing of the particle beam. The improvement consists of providing a radial electric field transverse to the accelerating electric fields and angularly introducing the beam of particles in the field. The results of the foregoing is to achieve a beam which spirals about the axis of the acceleration path. The combination of the electric fields and angular motion of the particles cooperate to provide a stable and focused particle beam.

  7. Synchronous scan-projection lithography on overall circumference of fine pipes with a diameter of 2 mm

    NASA Astrophysics Data System (ADS)

    Horiuchi, Toshiyuki; Furuhata, Takahiro; Muro, Hideyuki

    2016-06-01

    The scan-projection exposure of small-diameter pipe surfaces was investigated using a newly developed prototype exposure system. It is necessary to secure a very large depth of focus for printing thick resist patterns on round pipe surfaces with a roughness larger than that of semiconductor wafers. For this reason, a camera lens with a low numerical aperture of 0.089 was used as a projection lens, and the momentary exposure area was limited by a narrow slit with a width of 800 µm. Thus, patterns on a flat reticle were replicated on a pipe surface by linearly moving the reticle and rotating the pipe synchronously. By using a reticle with inclined line-and-space patterns, helical patterns with a width of 30 µm were successfully replicated on stainless-steel pipes with an outer diameter of 2 mm and coated with a 10-µm-thick negative resist. The patterns replicated at the start and stop edges were smoothly stitched seamlessly.

  8. Linear Clouds

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA03667 Linear Clouds

    These clouds are located near the edge of the south polar region. The cloud tops are the puffy white features in the bottom half of the image.

    Image information: VIS instrument. Latitude -80.1N, Longitude 52.1E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  9. Voltage divider based on submicron slits in a high Tc superconducting film and two bicrystal grain boundaries

    NASA Astrophysics Data System (ADS)

    Kaplunenko, V. K.; Ivanov, Z. G.; Stepantsov, E. A.; Claeson, T.; Wikborg, E.

    1995-07-01

    Experiments on a model of rapid single flux quantum (RSFQ) flip-flop cell, based on high-Tc (HTS) Josephson junctions show that it can operate as a voltage divider at frequency up to 400 GHz. The junctions were formed in YBaCuO film, deposited on novel Y-ZrO2 bicrystals with two asymmetric 32° grain boundaries, about 10 μm apart, and allow a new design of RSFQ logic based on a single HTS layer. Small inductances (≂10 pH) were made as narrow, submicron size slits. The junction widths were between 4 and 10 μm and for ten junctions located close to the tested circuits, the linear critical current densities at T=4.4 K were 10.7 μA/μm±50% for one grain boundary and 8.3 μA/μm±50% for the other one. IcRn was about 1 mV±50%. A current density of half the expected value meant that the test circuit did not act as an ideal flip-flop down to the lowest frequency. As a voltage divider it gave a half value division up to 0.82 mV at T=4.4 K and to 0.4 mV at 30 K.

  10. Laser beam scanning by rotary mirrors. I. Modeling mirror-scanning devices.

    PubMed

    Li, Y; Katz, J

    1995-10-01

    Avector approach to tracing the path of a laser beam through an optical system containing movable plane mirrors is described, which permits a unified treatment of a number of basic mirror-scanning devices. We show that the scan field produced by the mirror-scanning system is a curved surface with a straight line as its generating element. The cross section of the scan field can be a circle, an ellipse, or a curve in the shape of an egg. Based on this understanding, some advanced topics are addressed, e.g., the relationship between the scan field and the scan pattern, the dependence of the scan pattern on the location and orientation of the observation surface, optical distortions in a scan pattern, spot-size enlargement caused by non-normal incidence of the scan beam on the observation plane, and so on. Design equations and curves are derived for the mirror-scanning devices that most frequently exist in linear and circular scan technology. Part II contains an analysis of the galvanometer-based optical scanner paddle scanner and the regular polygon. In Part III, X-Y scanning systems are studied. PMID:21060488

  11. Abdominal CT scan

    MedlinePlus

    Computed tomography scan - abdomen; CT scan - abdomen; CT abdomen and pelvis ... 2016:chap 133. Radiologyinfo.org. Computed tomography (CT) - abdomen and pelvis. Updated June 16, 2016. www.radiologyinfo. ...

  12. RBC nuclear scan

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/003835.htm RBC nuclear scan To use the sharing features on this page, please enable JavaScript. An RBC nuclear scan uses small amounts of radioactive material to ...

  13. DOSE ASSESSMENT OF THE FINAL INVENTORIES IN CENTER SLIT TRENCHES ONE THROUGH FIVE

    SciTech Connect

    Collard, L.; Hamm, L.; Smith, F.

    2011-05-02

    In response to a request from Solid Waste Management (SWM), this study evaluates the performance of waste disposed in Slit Trenches 1-5 by calculating exposure doses and concentrations. As of 8/19/2010, Slit Trenches 1-5 have been filled and are closed to future waste disposal in support of an ARRA-funded interim operational cover project. Slit Trenches 6 and 7 are currently in operation and are not addressed within this analysis. Their current inventory limits are based on the 2008 SA and are not being impacted by this study. This analysis considers the location and the timing of waste disposal in Slit Trenches 1-5 throughout their operational life. In addition, the following improvements to the modeling approach have been incorporated into this analysis: (1) Final waste inventories from WITS are used for the base case analysis where variance in the reported final disposal inventories is addressed through a sensitivity analysis; (2) Updated K{sub d} values are used; (3) Area percentages of non-crushable containers are used in the analysis to determine expected infiltration flows for cases that consider collapse of these containers; (4) An updated representation of ETF carbon column vessels disposed in SLIT3-Unit F is used. Preliminary analyses indicated a problem meeting the groundwater beta-gamma dose limit because of high H-3 and I-129 release from the ETF vessels. The updated model uses results from a recent structural analysis of the ETF vessels indicating that water does not penetrate the vessels for about 130 years and that the vessels remain structurally intact throughout the 1130-year period of assessment; and (5) Operational covers are included with revised installation dates and sets of Slit Trenches that have a common cover. With the exception of the modeling enhancements noted above, the analysis follows the same methodology used in the 2008 PA (WSRC, 2008) and the 2008 SA (Collard and Hamm, 2008). Infiltration flows through the vadose zone are

  14. Scanning and storage of electrophoretic records

    DOEpatents

    McKean, Ronald A.; Stiegman, Jeff

    1990-01-01

    An electrophoretic record that includes at least one gel separation is mounted for motion laterally of the separation record. A light source is positioned to illuminate at least a portion of the record, and a linear array camera is positioned to have a field of view of the illuminated portion of the record and orthogonal to the direction of record motion. The elements of the linear array are scanned at increments of motion of the record across the field of view to develop a series of signals corresponding to intensity of light at each element at each scan increment.

  15. Correlation-steered scanning for scanning probe microscopes to overcome thermal drift for ultra-long time scanning.

    PubMed

    Zhang, Liansheng; Long, Qian; Liu, Yongbin; Zhang, Jie; Feng, Zhihua

    2016-07-01

    The thermal effect is one of the most important factors that influence the accuracy of nanoscale measurement and the surface topography of samples in scanning probe microscopes (SPMs). We propose a method called correlation-steered scanning, which is capable of overcoming three-dimensional thermal drifts in real time for ultra-long time scanned images. The image is scanned band by band with overlapping parts between adjacent bands. The vertical drift can be considered as linear and can thus be eliminated together with the tilt of the sample by applying the flattening method. Each band is artificially divided into several blocks for conveniently calculating lateral drifts on the basis of the overlapping area of adjacent bands through digital image correlation. The calculated lateral drifts are compensated to steer the scanning of the subsequent blocks, thus ensuring that all bands are parallel to one another. Experimental results proved that images scanned by the proposed method exhibited less distortions than those obtained from the traditional raster scanning method. The nanoscale measurement results based on the image obtained by the proposed method also showed high accuracy, with an error of less than 1.5%. By scanning as many bands as needed, the correlation-steered scanning method can obtain a highly precise SPM image of an ultra-large area.

  16. Scanning Seismic Intrusion Detector

    NASA Technical Reports Server (NTRS)

    Lee, R. D.

    1982-01-01

    Scanning seismic intrusion detector employs array of automatically or manually scanned sensors to determine approximate location of intruder. Automatic-scanning feature enables one operator to tend system of many sensors. Typical sensors used with new system are moving-coil seismic pickups. Detector finds uses in industrial security systems.

  17. Multipurpose binocular scanning apparatus

    NASA Technical Reports Server (NTRS)

    Chamberlain, F. R.; Parker, G. L.

    1969-01-01

    Optical gimballing apparatus directs narrow fields of view throughout solid angle approaching 4 pi steradians. Image rotation produced by scanning can be eliminated or altered by gear trains directly linked to the scanning drive assembly. It provides the basis for a binocular scanning capability.

  18. Slit2 and Robo1 induce opposing effects on metastasis of hepatocellular carcinoma Sk-hep-1 cells.

    PubMed

    Yuan, Mingjing; Guo, Hui; Li, Jing; Sui, Chengzhi; Qin, Ying; Wang, Jingjing; Khan, Yasir Hayat; Ye, Liying; Xie, Fuan; Wang, Heng; Yuan, Li; Ye, Jun

    2016-07-01

    The neural guidance molecular, Slit2, and its cognate receptor, Robo1, play critical roles in the development of the nervous system, nevertheless, their functions are not limited to this system. Numerous studies have shown decreased Slit2 expression in a wide variety of cancers, highlighting its potential as a tumor suppressor. However, the Slit2/Robo1 signaling axis was reported to induce either suppressive or stimulatory effects on tumor growth and metastasis, depending on cellular context. There is a paucity of information on the effects of the Slit2/Robo1 signaling axis on the growth and metastasis of human hepatocellular carcinoma (HCC). Large-scale data mining of the Oncomine database has revealed heterogeneous expression of Slit2 in HCC. We screened the Sk-hep-1, a cell line showing a relatively high level of Slit2, and low level of Robo1 expression. After Slit2 knockdown and Robo1 overexpression in these cells, we found Slit2 and Robo1 exerted opposing effects on tumor growth and metastasis both in in vitro and in vivo models. Slit2 knockdown and Robo1 overexpression in Sk-hep-1 cells promoted tumor growth and metastasis, suggesting a negative and positive role for Slit2 and Robo1, respectively, in tumor progression. Robo1 overexpression upregulated matrix metalloproteinase (MMP)2, -9 and membrane-type1 MMP (MT1-MMP) expression, stimulated MMP2, but not MMP9 activation, and downregulated expression of TIMP1 and 2. The PI3K/Akt signaling pathway is of importance in regulating MMP2 expression in Sk-hep-1 cells, since Robo1 overexpression stimulated phosphorylation of Akt while the PI3K inhibitor LY294002, significantly inhibited the upregulation of MMP2 and also the enhanced cell invasion induced by Robo1 overexpression. We postulate that Robo1 promotes tumor invasion partly by the upregulation of MMP2 after activation of PI3K/Akt signaling pathway. Notably, Slit2 knockdown caused the upregulation of Robo1 expression both at the mRNA and protein levels

  19. Optical vortex beams generated by a phase-only LC-SLM and double-slit interference analysis

    NASA Astrophysics Data System (ADS)

    Chen, Dong; Qi, Junli; Wang, Weihua; Yang, Jinhong; Wang, Ping; Zhang, Qianghua; Deng, Haifei; Zhang, Hui; Sun, Dewei; Shan, Huihui; Ma, Xiaomin; Shi, Bo

    2013-12-01

    Vortex beams with integral and fractional topological charges are generated by an experimental setup with one phase-only liquid crystal spatial light modulator which efficiently modulates the phase retardation distributions of input beam. The intensity distributions and double-slit interference of vortex beams with integral and fractional topological charges are investigated in detail. Tilt appears in double-slit interference fringes of vortex beams. The fringe tilt amounts in the intermediate region are proportional to the topological charge l of vortex beams. The double-slit interference method can be utilized to determine the topological charge of vortex beams.

  20. Pulmonary ventilation/perfusion scan

    MedlinePlus

    V/Q scan; Ventilation/perfusion scan; Lung ventilation/perfusion scan ... A pulmonary ventilation/perfusion scan is actually two tests. They may be done separately or together. During the perfusion scan, a health care ...

  1. Surface-plasmon-polariton hybridized cavity modes in submicrometer slits in a thin Au film

    NASA Astrophysics Data System (ADS)

    Walther, R.; Fritz, S.; Müller, E.; Schneider, R.; Maniv, T.; Cohen, H.; Matyssek, C.; Busch, K.; Gerthsen, D.

    2016-06-01

    The excitation of cavity standing waves in double-slit structures in thin gold films, with slit lengths between 400 and 2560 nm, was probed with a strongly focused electron beam in a transmission electron microscope. The energies and wavelengths of cavity modes up to the 11 th mode order were measured with electron energy loss spectroscopy to derive the corresponding dispersion relation. For all orders, a significant redshift of mode energies accompanied by a wavelength elongation relative to the expected resonator energies and wavelengths is observed. The resultant dispersion relation is found to closely follow the well-known dispersion law of surface-plasmon polaritons (SPPs) propagating on a gold/air interface, thus providing direct evidence for the hybridized nature of the detected cavity modes with SPPs.

  2. Towards a clean slit: how medicine and notions of normality are shaping female genital aesthetics.

    PubMed

    McDougall, Lindy Joan

    2013-01-01

    In the West, a specific ideal has emerged for female genitalia. The ideal is one of absence, a clean slit that can be attained through the removal of pubic hair and, increasingly, through female genital cosmetic surgery. This ideal is largely created in the media, which generates contradictory messages for women. The popular press, backed by medical opinion, explicitly acknowledges that a wide range of variation is normal--female genitals vary in appearance 'about as much as snowflakes'--but by showing only altered minimalist clean slits, it carries an implicit message that women should be worried if their genitals do not match up to this exacting ideal. Consequently, some women feel their genitals are not satisfactory and choose surgery. Using biomedicine to fix normal body parts in order to fashion desirable femininity, releases medicine from its rigid scientific underpinnings exposing it as an increasingly cultural and commercial pursuit.

  3. Slit/Robo signaling regulates cell fate decisions in the intestinal stem cell lineage of Drosophila

    PubMed Central

    Biteau, Benoît; Jasper, Heinrich

    2014-01-01

    To maintain tissue homeostasis, cell fate decisions within stem cell lineages have to respond to the needs of the tissue. This coordination of lineage choices with regenerative demand remains poorly characterized. Here we identify a signal from enteroendocrine cells (EEs) that controls lineage specification in the Drosophila intestine. We find that EEs secrete Slit, a ligand for the Robo2 receptor in stem cells (ISCs) that limits ISC commitment to the endocrine lineage, establishing negative feedback control of EE regeneration. We further show that this lineage decision is made within ISCs and requires induction of the transcription factor Prospero in ISCs. Our work identifies a new function for the conserved Slit/Robo pathway in the regulation of adult stem cells, establishing negative feedback control of ISC lineage specification as a critical strategy to preserve tissue homeostasis. Our results further amend the current understanding of cell fate commitment within the Drosophila ISC lineage. PMID:24931602

  4. The Electrochemistry with Lithium versus Sodium of Selenium Confined To Slit Micropores in Carbon.

    PubMed

    Xin, Sen; Yu, Le; You, Ya; Cong, Huai-Ping; Yin, Ya-Xia; Du, Xue-Li; Guo, Yu-Guo; Yu, Shu-Hong; Cui, Yi; Goodenough, John B

    2016-07-13

    Substitution of selenium for sulfur in the cathode of a rechargeable battery containing Sx molecules in microporous slits in carbon allows a better characterization of the electrochemical reactions that occur. Paired with a metallic lithium anode, the Sex chains are converted to Li2Se in a single-step reaction. With a sodium anode, a sequential chemical reaction is characterized by a continuous chain shortening of Sex upon initial discharge before completing the reduction to Na2Se; on charge, the reconstituted Sex molecules retain a smaller x value than the original Sex chain molecule. In both cases, the Se molecules remain almost completely confined to the micropore slits to give a long cycle life. PMID:27347697

  5. Numerical simulation of thermoacoustic response of laboratory scale premixed multi-slit burner flames

    NASA Astrophysics Data System (ADS)

    O'Brien, Adam

    Thermoacoustic instabilities are an entirely unwanted, yet nearly inevitable phenomenon occurring in many practical premixed combustors. If not properly accounted and designed for, they can incur significant increases in the development combustion systems. The fact that such unexpected issues are encountered is indicative of a fundamental lack of understanding regarding the mechanisms that drive thermoacoustic phenomena. Numerical techniques are used to characterize the thermoacoustic response of premixed multi-slit bunsen burner flames. A symmetrical representation of the multi-slit burner is used, and the transfer function is computed at several different frequencies and at three different equivalence ratios. The numerical results are then compared against experimental results in order to determine the suitability of numerical techniques for studying thermoacoustics. A fully compressible Navier-Stokes combustion solver is used in conjunction with adaptive mesh refinement (AMR) for improved resolution at the flame interface.

  6. Analytical and experimental study on mild steel dampers with non-uniform vertical slits

    NASA Astrophysics Data System (ADS)

    Zheng, Jie; Li, Aiqun; Guo, Tong

    2015-03-01

    This study proposes a novel mild steel damper with non-uniform vertical slits. The influence of different shapes of vertical slits of the core energy plate on the energy dissipation and buckling resistance capacities is analyzed. Based on the theoretical analysis, formulas of key parameters of the dampers, including the elastic lateral stiffness, shear bearing capacity and yield displacement, are derived. The effectiveness of the proposed damper is demonstrated through pseudo static tests on four 0.25-scale specimens. Performance of these dampers, i.e. cyclic deformation, stress distribution, energy dissipation capacity, etc., are presented and discussed. Using the numerical models of dampers calibrated through test data, earthquake time-history analyses were conducted, and it is observed that the dampers significantly reduce the seismic responses of the prototype frame and have a desirable energy dissipation capacity.

  7. The Electrochemistry with Lithium versus Sodium of Selenium Confined To Slit Micropores in Carbon.

    PubMed

    Xin, Sen; Yu, Le; You, Ya; Cong, Huai-Ping; Yin, Ya-Xia; Du, Xue-Li; Guo, Yu-Guo; Yu, Shu-Hong; Cui, Yi; Goodenough, John B

    2016-07-13

    Substitution of selenium for sulfur in the cathode of a rechargeable battery containing Sx molecules in microporous slits in carbon allows a better characterization of the electrochemical reactions that occur. Paired with a metallic lithium anode, the Sex chains are converted to Li2Se in a single-step reaction. With a sodium anode, a sequential chemical reaction is characterized by a continuous chain shortening of Sex upon initial discharge before completing the reduction to Na2Se; on charge, the reconstituted Sex molecules retain a smaller x value than the original Sex chain molecule. In both cases, the Se molecules remain almost completely confined to the micropore slits to give a long cycle life.

  8. Modifying the optical path in a nonlinear double-slit experiment

    NASA Astrophysics Data System (ADS)

    Paltoglou, Vassilis; Efremidis, Nikolaos K.

    2015-11-01

    In this letter, we study a nonlinear interferometric setup based on diffraction rather than beam combining. It consists of a nonlinear analogue of Young's double-slit experiment where a nonlinear material is placed exactly after one of the slits. The presence of nonlinearity breaks the transverse spatial symmetry of the system and thus modifies the optical path. For moderate nonlinearities this leads to a self-induced shift of the intensity pattern in the transverse plane. A simple theoretical model is developed which is surprisingly accurate in predicting the intensity profile of the main lobes for a wide range of parameters. We discuss about possible applications of our model in nonlinear interferometry, for example in measuring the nonlinearities of optical materials.

  9. Modifying the optical path in a nonlinear double-slit experiment.

    PubMed

    Paltoglou, Vassilis; Efremidis, Nikolaos K

    2015-11-15

    In this Letter, we study a nonlinear interferometric setup based on diffraction, rather than beam combining. It consists of a nonlinear analog of Young's double-slit experiment where a nonlinear material is placed exactly after one of the slits. The presence of nonlinearity breaks the transverse spatial symmetry of the system and, thus, modifies the optical path. For moderate nonlinearities, this leads to a self-induced shift of the intensity pattern in the transverse plane. A simple theoretical model is developed which is surprisingly accurate in predicting the intensity profile of the main lobes for a wide range of parameters. We discuss possible applications of our model in nonlinear interferometry, for example in measuring the nonlinearities of optical materials.

  10. Implementation of rectangular slit-inserted ultra-wideband tapered slot antenna.

    PubMed

    Kim, Sun-Woong; Choi, Dong-You

    2016-01-01

    In this paper, a tapered slot antenna capable of ultra-wideband communication was designed. In the proposed antenna, rectangular slits were inserted to enhance the bandwidth and reduce the area of the antenna. The rectangular slit-inserted tapered slot antenna operated at a bandwidth of 8.45 GHz, and the bandwidth improved upon the basic tapered slot antenna by 4.72 GHz. The radiation pattern of the antenna was suitable for location recognition in a certain direction owing to an appropriate 3 dB beam width. The antenna gain was analyzed within the proposed bandwidth, and the highest gain characteristic at 7.55 dBi was exhibited at a 5-GHz band. The simulation and measurement results of the proposed tapered slot antenna were similar. PMID:27610306

  11. Slit/Robo signaling regulates cell fate decisions in the intestinal stem cell lineage of Drosophila.

    PubMed

    Biteau, Benoît; Jasper, Heinrich

    2014-06-26

    In order to maintain tissue homeostasis, cell fate decisions within stem cell lineages have to respond to the needs of the tissue. This coordination of lineage choices with regenerative demand remains poorly characterized. Here, we identify a signal from enteroendocrine cells (EEs) that controls lineage specification in the Drosophila intestine. We find that EEs secrete Slit, a ligand for the Robo2 receptor in intestinal stem cells (ISCs) that limits ISC commitment to the endocrine lineage, establishing negative feedback control of EE regeneration. Furthermore, we show that this lineage decision is made within ISCs and requires induction of the transcription factor Prospero in ISCs. Our work identifies a function for the conserved Slit/Robo pathway in the regulation of adult stem cells, establishing negative feedback control of ISC lineage specification as a critical strategy to preserve tissue homeostasis. Our results further amend the current understanding of cell fate commitment within the Drosophila ISC lineage. PMID:24931602

  12. Optical imaging and long-slit spectroscopy of Markarian galaxies with multiple nuclei. I - Basic data

    NASA Technical Reports Server (NTRS)

    Mazzarella, Joseph M.; Boroson, Todd A.

    1993-01-01

    Optical CCD images and long-slit spectroscopic data are presented for over 100 Markarian (UV-excess) galaxies reported in early studies to possess multiple optical nuclei or extreme morphological peculiarities suggestive of galaxy collisions and mergers. Stacked broad-band images are presented with histogram equalization in order to show simultaneously the nuclei and features at very low surface-brightness levels. Morphological properties, luminosities and colors of the integral systems are given. Photometric and image properties of over 200 individual nuclei and giant H II regions have been measured with respect to the local backgrounds in the galaxies using an objective image finding algorithm. Labeled contour plots identify the measured subcomponents. Two-dimensional spectral data are presented, in addition to intensity profiles along the slit in the light of H-alpha + forbidden N II emission lines and adjacent continuum. Nuclear emission-line measurements, reddening estimates, monochromatic continuum magnitudes, and colors are given.

  13. Slit/Robo signaling regulates cell fate decisions in the intestinal stem cell lineage of Drosophila.

    PubMed

    Biteau, Benoît; Jasper, Heinrich

    2014-06-26

    In order to maintain tissue homeostasis, cell fate decisions within stem cell lineages have to respond to the needs of the tissue. This coordination of lineage choices with regenerative demand remains poorly characterized. Here, we identify a signal from enteroendocrine cells (EEs) that controls lineage specification in the Drosophila intestine. We find that EEs secrete Slit, a ligand for the Robo2 receptor in intestinal stem cells (ISCs) that limits ISC commitment to the endocrine lineage, establishing negative feedback control of EE regeneration. Furthermore, we show that this lineage decision is made within ISCs and requires induction of the transcription factor Prospero in ISCs. Our work identifies a function for the conserved Slit/Robo pathway in the regulation of adult stem cells, establishing negative feedback control of ISC lineage specification as a critical strategy to preserve tissue homeostasis. Our results further amend the current understanding of cell fate commitment within the Drosophila ISC lineage.

  14. Photographic recording of slit-lamp appearances of the ocular fundus.

    PubMed Central

    Kenyeres, P; Slezak, H

    1986-01-01

    The four methods of illumination in the use of slit-lamp biomicroscopy of the anterior segment, described first by Vogt, are equally useful in the posterior part of the eye. Examination of the ocular fundus is more difficult. In particular, photography of the central and peripheral parts of the fundus demands additional technical arrangements if all the appearances of biomicroscopy are to be recorded. Images PMID:3778859

  15. Potential of Lactobacillus curvatus LFC1 to produce slits in Cheddar cheese.

    PubMed

    Porcellato, D; Johnson, M E; Houck, K; Skeie, S B; Mills, D A; Kalanetra, K M; Steele, J L

    2015-08-01

    Defects in Cheddar cheese resulting from undesired gas production are a sporadic problem that results in significant financial losses in the cheese industry. In this study, we evaluate the potential of a facultatively heterofermentative lactobacilli, Lactobacillus curvatus LFC1, to produce slits, a gas related defect in Cheddar cheese. The addition of Lb. curvatus LFC1 to cheese milk at log 3 CFU/ml resulted in the development of small slits during the first month of ripening. Chemical analyses indicated that the LFC1 containing cheeses had less galactose and higher levels of lactate and acetate than the control cheeses. The composition the cheese microbiota was examined through a combination of two culture independent approaches, 16S rRNA marker gene sequencing and automated ribosomal intergenic spacer analysis; the results indicated that no known gas producers were present and that high levels of LFC1 was the only significant difference between the cheese microbiotas. A ripening cheese model system was utilized to examine the metabolism of LFC1 under conditions similar to those present in cheeses that exhibited the slit defect. The combined cheese and model system results indicate that when Lb. curvatus LFC1 was added to the cheese milk at log 3 CFU/ml it metabolized galactose to lactate, acetate, and CO2. For production of sufficient CO2 to result in the formation of slits there needs to be sufficient galactose and Lb. curvatus LFC1 present in the cheese matrix. To our knowledge, facultatively heterofermentative lactobacilli have not previously been demonstrated to result in gas-related cheese defects.

  16. Potential of Lactobacillus curvatus LFC1 to produce slits in Cheddar cheese.

    PubMed

    Porcellato, D; Johnson, M E; Houck, K; Skeie, S B; Mills, D A; Kalanetra, K M; Steele, J L

    2015-08-01

    Defects in Cheddar cheese resulting from undesired gas production are a sporadic problem that results in significant financial losses in the cheese industry. In this study, we evaluate the potential of a facultatively heterofermentative lactobacilli, Lactobacillus curvatus LFC1, to produce slits, a gas related defect in Cheddar cheese. The addition of Lb. curvatus LFC1 to cheese milk at log 3 CFU/ml resulted in the development of small slits during the first month of ripening. Chemical analyses indicated that the LFC1 containing cheeses had less galactose and higher levels of lactate and acetate than the control cheeses. The composition the cheese microbiota was examined through a combination of two culture independent approaches, 16S rRNA marker gene sequencing and automated ribosomal intergenic spacer analysis; the results indicated that no known gas producers were present and that high levels of LFC1 was the only significant difference between the cheese microbiotas. A ripening cheese model system was utilized to examine the metabolism of LFC1 under conditions similar to those present in cheeses that exhibited the slit defect. The combined cheese and model system results indicate that when Lb. curvatus LFC1 was added to the cheese milk at log 3 CFU/ml it metabolized galactose to lactate, acetate, and CO2. For production of sufficient CO2 to result in the formation of slits there needs to be sufficient galactose and Lb. curvatus LFC1 present in the cheese matrix. To our knowledge, facultatively heterofermentative lactobacilli have not previously been demonstrated to result in gas-related cheese defects. PMID:25846916

  17. Theoretical and numerical analyses of a slit-masked chicane for modulated bunch generation

    DOE PAGES

    Zhu, Xiaofang; Broemmelsiek, Daniel R.; Shin, Young -Min; Fermi National Accelerator Lab.

    2015-10-28

    Density modulations on electron beams can improve machine performance of beam-driven accelerators and FELs with resonance beam-wave coupling. The beam modulation is studied with a masked chicane by the analytic model and simulations with the beam parameters of the Fermilab Accelerator Science and Technology (FAST) facility. With the chicane design parameters (bending angle of 18o, bending radius of 0.95 m and R56 ~ –0.19 m) and a nominal beam of 3 ps bunch length, the analytic model showed that a slit-mask with slit period 900 μ m and aperture width 300 μ m induces a modulation of bunch-to-bunch spacing ~more » 100 μ m to the bunch with 2.4% correlated energy spread. With the designed slit mask and a 3 ps bunch, particle-in-cell (PIC) simulations, including nonlinear energy distributions, space charge force, and coherent synchrotron radiation (CSR) effect, also result in beam modulation with bunch-to-bunch distance around 100 μ m and a corresponding modulation frequency of 3 THz. The beam modulation has been extensively examined with three different beam conditions, 2.25 ps (0.25 nC), 3.25 ps (1 nC), and 4.75 ps (3.2 nC), by tracking code Elegant. The simulation analysis indicates that the sliced beam by the slit-mask with 3 ~ 6% correlated energy spread has modulation lengths about 187 μ m (0.25 nC), 270 μ m (1 nC) and 325 μ m (3.2 nC). As a result, the theoretical and numerical data proved the capability of the designed masked chicane in producing modulated bunch train with micro-bunch length around 100 fs.« less

  18. Molecular dynamics simulation of benzene in graphite and amorphous carbon slit pores.

    PubMed

    Fomin, Yu D

    2013-11-15

    It is well known that confining a liquid into a pore strongly alters the liquid behavior. Investigations of the effect of confinement are of great importance for many scientific and technological applications. Here, we present a study of the behavior of benzene confined in carbon slit pores. Two types of pores are considered-graphite and amorphous carbon ones. We show that the effect of different pore structure is of crucial importance for the benzene behavior.

  19. Theoretical and numerical analyses of a slit-masked chicane for modulated bunch generation

    NASA Astrophysics Data System (ADS)

    Zhu, X.; Broemmelsiek, D. R.; Shin, Y.-M.

    2015-10-01

    Density modulations on electron beams can improve machine performance of beam-driven accelerators and FELs with resonance beam-wave coupling. The beam modulation is studied with a masked chicane by the analytic model and simulations with the beam parameters of the Fermilab Accelerator Science and Technology (FAST) facility. With the chicane design parameters (bending angle of 18o, bending radius of 0.95 m and R56 ~ -0.19 m) and a nominal beam of 3 ps bunch length, the analytic model showed that a slit-mask with slit period 900 μ m and aperture width 300 μ m induces a modulation of bunch-to-bunch spacing ~ 100 μ m to the bunch with 2.4% correlated energy spread. With the designed slit mask and a 3 ps bunch, particle-in-cell (PIC) simulations, including nonlinear energy distributions, space charge force, and coherent synchrotron radiation (CSR) effect, also result in beam modulation with bunch-to-bunch distance around 100 μ m and a corresponding modulation frequency of 3 THz. The beam modulation has been extensively examined with three different beam conditions, 2.25 ps (0.25 nC), 3.25 ps (1 nC), and 4.75 ps (3.2 nC), by tracking code Elegant. The simulation analysis indicates that the sliced beam by the slit-mask with 3 ~ 6% correlated energy spread has modulation lengths about 187 μ m (0.25 nC), 270 μ m (1 nC) and 325 μ m (3.2 nC). The theoretical and numerical data proved the capability of the designed masked chicane in producing modulated bunch train with micro-bunch length around 100 fs.

  20. What dynamics can be expected for mixed states in two-slit experiments?

    SciTech Connect

    Luis, Alfredo; Sanz, Ángel S.

    2015-06-15

    Weak-measurement-based experiments (Kocsis et al., 2011) have shown that, at least for pure states, the average evolution of independent photons in Young’s two-slit experiment is in compliance with the trajectories prescribed by the Bohmian formulation of quantum mechanics. But, what happens if the same experiment is repeated assuming that the wave function associated with each particle is different, i.e., in the case of mixed (incoherent) states? This question is investigated here by means of two alternative numerical simulations of Young’s experiment, purposely devised to be easily implemented and tested in the laboratory. Contrary to what could be expected a priori, it is found that even for conditions of maximal mixedness or incoherence (total lack of interference fringes), experimental data will render a puzzling and challenging outcome: the average particle trajectories will still display features analogous to those for pure states, i.e., independently of how mixedness arises, the associated dynamics is influenced by both slits at the same time. Physically this simply means that weak measurements are not able to discriminate how mixedness arises in the experiment, since they only provide information about the averaged system dynamics. - Highlights: • The dynamics associated with mixture states in investigated by means of two simple Young’s two-slit models. • The models are prepared to be easily implemented and tested in the laboratory by means of weak measurements. • Bohmian mechanics has been generalized to encompass statistical mixtures. • Even for conditions of maximal mixedness numerical simulations show that the dynamics is strongly influenced by both slits. • Accordingly, weak measurements are unable to discriminate how mixedness arises in an experiment.

  1. Sub-Doppler infrared spectroscopy and formation dynamics of triacetylene in a slit supersonic expansion

    NASA Astrophysics Data System (ADS)

    Chang, Chih-Hsuan; Agarwal, Jay; Allen, Wesley D.; Nesbitt, David J.

    2016-02-01

    Infrared spectroscopy and formation dynamics of triacetylene are investigated in a slit jet supersonic discharge and probed with sub-Doppler resolution (≈60 MHz) on the fundamental antisymmetric CH stretch mode (ν5). The triacetylene is generated in the throat of the discharge by sequential attack of ethynyl radical with acetyelene and diacetylene: (i) HCCH → HCC + H, (ii) HCC + HCCH → HCCCCH + H, (iii) HCC + HCCCCH → HCCCCCCH + H, cooled rapidly in the slit expansion to 15 K, and probed by near shot-noise-limited absorption sensitivity with a tunable difference-frequency infrared laser. The combination of jet cooled temperatures (Trot = 15 K) and low spectral congestion permits (i) analysis of rotationally avoided crossings in the ν5 band ascribed to Coriolis interactions, as well as (ii) first detection of ν5 Π-Π hot band progressions built on the ν12 sym CC bend and definitively assigned via state-of-the-art ab initio vibration-rotation interaction parameters (αi), which make for interesting comparison with recent spectroscopic studies of Doney et al. [J. Mol. Spectrosc. 316, 54 (2015)]. The combined data provide direct evidence for significantly non-equilibrium populations in the CC bending manifold, dynamically consistent with a strongly bent radical intermediate and transition states for forming triacetylene product. The presence of intense triacetylene signals under cold, low density slit jet conditions provides support for (i) barrierless addition of HCC with HCCCCH and (ii) a high quantum yield for HCCCCCCH formation. Complete basis set calculations for energetics [CCSD(T)-f12/VnZ-f12, n = 2,3] and frequencies [CCSD(T)-f12/VdZ-f12] are presented for both radical intermediate and transition state species, predicting collision stabilization in the slit jet expansion to be competitive with unimolecular decomposition with increasing polyyne chain length.

  2. LIRIS: A Long-Slit Intermediate Resolution Infrared Sectrograph for the WHT

    NASA Astrophysics Data System (ADS)

    Acosta-Pulido, J.; Ballesteros, E.; Barreto, M.; Correa, S.; Delgado, J. M.; Dominguez-Tagle, C.; Hernandez, E.; Lopez, R.; Manchado, A.; Manescau, A.; Moreno, H.; Prada, F.; Redondo, P.; Sanchez, V.; Tenegi, F.

    2002-10-01

    LIRIS is an Instituto de Astrofísica de Canarias (IAC) project that consists in a near-infrared (0.9-2.4microns) intermediate resolution spectrograph, conceived as a common user instrument for the WHT. LIRIS will have imaging, long-slit and multi-object spectroscopy observing modes (~1000-3000 Å). Coronography, and polarimetry capabilities will eventually be added. Image capability will allow easy target acquisition for spectroscopy.

  3. Single-Slit Diffraction: Transitioning from Geometric Optics to the Fraunhofer Regime

    ERIC Educational Resources Information Center

    Panuski, Christopher L.; Mungan, Carl E.

    2016-01-01

    Suppose a red laser beam (of wavelength ? equal to 0.660 µm) is expanded using an optical telescope into a collimated, approximately plane wave that is 5.68 mm in diameter. Pass that beam through a tall rectangular slit whose width "a" is gradually reduced from 3.30 to 0.100 mm. Look at its image on a screen located at a distance…

  4. Theoretical and numerical analyses of a slit-masked chicane for modulated bunch generation

    SciTech Connect

    Zhu, Xiaofang; Broemmelsiek, Daniel R.; Shin, Young -Min

    2015-10-28

    Density modulations on electron beams can improve machine performance of beam-driven accelerators and FELs with resonance beam-wave coupling. The beam modulation is studied with a masked chicane by the analytic model and simulations with the beam parameters of the Fermilab Accelerator Science and Technology (FAST) facility. With the chicane design parameters (bending angle of 18o, bending radius of 0.95 m and R56 ~ –0.19 m) and a nominal beam of 3 ps bunch length, the analytic model showed that a slit-mask with slit period 900 μ m and aperture width 300 μ m induces a modulation of bunch-to-bunch spacing ~ 100 μ m to the bunch with 2.4% correlated energy spread. With the designed slit mask and a 3 ps bunch, particle-in-cell (PIC) simulations, including nonlinear energy distributions, space charge force, and coherent synchrotron radiation (CSR) effect, also result in beam modulation with bunch-to-bunch distance around 100 μ m and a corresponding modulation frequency of 3 THz. The beam modulation has been extensively examined with three different beam conditions, 2.25 ps (0.25 nC), 3.25 ps (1 nC), and 4.75 ps (3.2 nC), by tracking code Elegant. The simulation analysis indicates that the sliced beam by the slit-mask with 3 ~ 6% correlated energy spread has modulation lengths about 187 μ m (0.25 nC), 270 μ m (1 nC) and 325 μ m (3.2 nC). As a result, the theoretical and numerical data proved the capability of the designed masked chicane in producing modulated bunch train with micro-bunch length around 100 fs.

  5. Integration status of the configurable slit unit for GTC-EMIR

    NASA Astrophysics Data System (ADS)

    Teuwen, M.; Janssen, H.; Casalta, J. M.; Garzón Lopez, F.

    2012-09-01

    The Configurable Slit Unit (CSU) is a key module of EMIR (wide field NIR multi-object spectrograph) which will be one of the key next generation instruments of the Gran Telescopio de Canarias (GTC). The CSU enables a multi-slit configuration, a long slit, or an imaging aperture in the 6'x6' (340mm x 340mm) field of view. This is realized by 110 sliding bars which can be configured at cryogenic working temperature to create 55 slits with a position accuracy of 6 micron. The CSU incorporates a number of enabling technologies which have been developed, validated and matured as a part of the total development of the CSU. Dedicated actuator drive and position measurement technologies have been successfully developed. Also a selective surface treatment technology, to give detailed features on the same part opposite emissivity performances, has been developed. All these technologies are currently implemented in the realization of the unit. Manufacturing of components for the unit has challenged state of the art production equipment and skills to the limit due to the size, number, accuracy and complexity of the parts and features. Integration and verification of the CSU is advancing. Both mechanics as electronics have been tested at sub-module level. Ahead is the challenge of actual integration of the electronics and software in order to get the mechanical hardware to operate within specification. Control strategies are developed and tuned to guarantee robust operation of the unit in cryogenic working environment. As a final integration step all individual axes are calibrated with an external interferometer measurement system.

  6. Comparison of circular and polygonal planar orbits for pinhole and slit-slat SPECT

    PubMed Central

    Accorsi, Roberto; Ayan, Ahmet S.; Metzler, Scott D.

    2010-01-01

    Analytic formulas and Monte Carlo simulation are used to calculate and compare the sensitivity of circular and polygonal orbits at different points in the Field of View (FoV) for both pinhole and slit-slat collimation. Results show that for a given slit-slat collimator an N-sided polygonal orbit tangent to the FoV generally provides average sensitivity lower than the tightest circular orbit consistent with the same aperture angle, but with better spatial resolution that can be traded for sensitivity for a constant-resolution comparison. This generally results in a slight advantage for the polygonal orbit. However, this advantage depends on the clearance that must be allowed between the orbit and the FoV and decreases quickly, vanishing when even a few millimeters of space are left, which in practice is necessary to accommodate mechanical constraints. For a pinhole collimator the advantage for the tangent polygonal orbit is more consistent, but similar conclusions are reached again when clearance is considered. A direct comparison at constant resolution between slit-slat and pinhole collimation in a single transverse plane is shown to be possible with parameters typical of small-animal imaging applications only for detectors with excellent intrinsic resolution; in this case, pinhole collimation is shown to be more sensitive in magnifying geometries, but reduced axial FoV and increased axial blurring should also be considered for a more complete comparison. PMID:20204152

  7. Experimental and numerical investigation of the acoustic response of multi-slit Bunsen burners

    SciTech Connect

    Kornilov, V.N.; de Goey, L.P.H.

    2009-10-15

    Experimental and numerical techniques to characterize the response of premixed methane-air flames to acoustic waves are discussed and applied to a multi-slit Bunsen burner. The steady flame shape, flame front kinematics and flow field of acoustically exited flames, as well as the flame transfer function and matrix are computed. The numerical results are compared with experiments. The influence of changes in the mean flow velocity, mixture equivalence ratio, slit width and distance between the slits on the transfer function is studied, both numerically and experimentally. Good agreement is found which indicates the suitability of both the experimental and numerical approach and shows the importance of predicting the influence of the flow on the flame and vice versa. On the basis of the results obtained, the role and physical nature of convective flow structures, heat transfer between the flame and burner plate and interaction between adjacent flames are discussed. Suggestions for analytical models of premixed flame-acoustics interaction are formulated. (author)

  8. Electronically tunable extraordinary optical transmission in graphene plasmonic ribbons coupled to subwavelength metallic slit arrays.

    PubMed

    Kim, Seyoon; Jang, Min Seok; Brar, Victor W; Tolstova, Yulia; Mauser, Kelly W; Atwater, Harry A

    2016-01-01

    Subwavelength metallic slit arrays have been shown to exhibit extraordinary optical transmission, whereby tunnelling surface plasmonic waves constructively interfere to create large forward light propagation. The intricate balancing needed for this interference to occur allows for resonant transmission to be highly sensitive to changes in the environment. Here we demonstrate that extraordinary optical transmission resonance can be coupled to electrostatically tunable graphene plasmonic ribbons to create electrostatic modulation of mid-infrared light. Absorption in graphene plasmonic ribbons situated inside metallic slits can efficiently block the coupling channel for resonant transmission, leading to a suppression of transmission. Full-wave simulations predict a transmission modulation of 95.7% via this mechanism. Experimental measurements reveal a modulation efficiency of 28.6% in transmission at 1,397 cm(-1), corresponding to a 2.67-fold improvement over transmission without a metallic slit array. This work paves the way for enhancing light modulation in graphene plasmonics by employing noble metal plasmonic structures. PMID:27499258

  9. Fundus image mosaicking for information augmentation in computer-assisted slit-lamp imaging.

    PubMed

    Richa, Rogério; Linhares, Rodrigo; Comunello, Eros; von Wangenheim, Aldo; Schnitzler, Jean-Yves; Wassmer, Benjamin; Guillemot, Claire; Thuret, Gilles; Gain, Philippe; Hager, Gregory; Taylor, Russell

    2014-06-01

    Laser photocoagulation is currently the standard treatment for sight-threatening diseases worldwide, namely diabetic retinopathy and retinal vein occlusions. The slit lamp biomicroscope is the most commonly used device for this procedure, specially for the treatment of the eye periphery. However, only a small portion of the retina can be visualized through the biomicroscope, complicating the task of localizing and identifying surgical targets, increasing treatment duration and patient discomfort. In order to assist surgeons, we propose a method for creating intraoperative retina maps for view expansion using a slit-lamp device. Based on the mosaicking method described by Richa et al, 2012, the proposed method is a combination of direct and feature-based methods, suitable for the textured nature of the human retina. In this paper, we describe three major enhancements to the original formulation. The first is a visual tracking method using local illumination compensation to cope with the challenging visualization conditions. The second is an efficient pixel selection scheme for increased computational efficiency. The third is an entropy-based mosaic update method to dynamically improve the retina map during exploration. To evaluate the performance of the proposed method, we conducted several experiments on human subjects with a computer-assisted slit-lamp prototype. We also demonstrate the practical value of the system for photo documentation, diagnosis and intraoperative navigation. PMID:24718569

  10. Optical Focusing by Planar Lenses Based on Nano-scale Metallic Slits in Visible Regime

    NASA Astrophysics Data System (ADS)

    Feng, Di; Zhang, Chunxi

    A kind of planar metallic lenses is proposed to realize optical focusing in the visible wavelength through a metallic film with nano-scale slit arrays, which have the same depth but tuning widths. Due to the subwavelength and aperiodic nature of planar metallic lenses, we present the rigorous electromagnetic analysis by using two dimensional finite difference time domain method. The electromagnetic wave transports through the tuning slits in the form of surface plasmon polaritons, and gets the required phase retardations to focusing at the focal plane. We analyze the focusing characteristics of planar dielectric lens and metallic lens with tuning widths that are obtained by generalizing the relevant phase delay, for different incidence polarization waves (TM polarized case and TE polarized case). The computational calculation results show that, extraordinary optical transmission of surface plasmon polaritions through non uniform nano-scale metallic slits is observed, and it has contributions to the optical focusing, but cannot increase the focal energy compared with dielectric planar lens with the same profile, and the metallic lenses are more sensitive to the polarization of incidence wave than that of dielectric lenses. The influence of metallic lenses' thickness on the focal characteristics has been analyzed also.

  11. Long slit spectroscopy of NH2 in comets Halley, Wilson, and Nishikawa-Takamizawa-Tago

    NASA Technical Reports Server (NTRS)

    Rettig, Terrence W.; Tegler, Stephen C.; Wyckoff, Susan; Heyd, Rodney; Stathkis, Raylee; Ramsay, D. A.

    1992-01-01

    Long-slit spectra of comets Halley, Wilson and Nishikawa-Takamizawa-Tago were obtained with the 3.9 meter Anglo-Australian Telescope. Spectra of comets Halley and Wilson were obtained with the IPCS at a spectral resolution of 0.5 A and a spatial resolution of 10(exp 3) km. Spectra of comets Wilson and Nishikawa-Takamizawa-Tago were obtained with a CCD at a spectral resolution of 1.5 A and a spatial resolution of approximately 3 x 10(exp 3) km. Surface brightness profiles for NH2 were extracted from the long-slit spectra of each comet. The observed surface brightness profiles extend along the slit to approximately 6 x 10(exp 4) km from the nucleus in both sunward and tailward directions. By comparing surface distribution calculated from an appropriate coma model with observed surface brightness distributions, the photodissociation timescale of the parent molecule of NH2 can be inferred. The observed NH2 surface brightness profiles in all three comets compares well with a surface brightness profile calculated using the vectorial model, an NH3 photodissociation timescale of 7 x 10(exp 3) seconds, and an NH2 photodissociation timescale of 34,000 seconds.

  12. MuSICa: the Multi-Slit Image Slicer for the est Spectrograph

    NASA Astrophysics Data System (ADS)

    Calcines, A.; López, R. L.; Collados, M.

    2013-09-01

    Integral field spectroscopy (IFS) is a technique that allows one to obtain the spectra of all the points of a bidimensional field of view simultaneously. It is being applied to the new generation of the largest night-time telescopes but it is also an innovative technique for solar physics. This paper presents the design of a new image slicer, MuSICa (Multi-Slit Image slicer based on collimator-Camera), for the integral field spectrograph of the 4-m aperture European Solar Telescope (EST). MuSICa is a multi-slit image slicer that decomposes an 80 arcsec2 field of view into slices of 50 μm and reorganizes it into eight slits of 0.05 arcsec width × 200 arcsec length. It is a telecentric system with an optical quality at diffraction limit compatible with the two modes of operation of the spectrograph: spectroscopic and spectro-polarimetric. This paper shows the requirements, technical characteristics and layout of MuSICa, as well as other studied design options.

  13. Electronically tunable extraordinary optical transmission in graphene plasmonic ribbons coupled to subwavelength metallic slit arrays

    PubMed Central

    Kim, Seyoon; Jang, Min Seok; Brar, Victor W.; Tolstova, Yulia; Mauser, Kelly W.; Atwater, Harry A.

    2016-01-01

    Subwavelength metallic slit arrays have been shown to exhibit extraordinary optical transmission, whereby tunnelling surface plasmonic waves constructively interfere to create large forward light propagation. The intricate balancing needed for this interference to occur allows for resonant transmission to be highly sensitive to changes in the environment. Here we demonstrate that extraordinary optical transmission resonance can be coupled to electrostatically tunable graphene plasmonic ribbons to create electrostatic modulation of mid-infrared light. Absorption in graphene plasmonic ribbons situated inside metallic slits can efficiently block the coupling channel for resonant transmission, leading to a suppression of transmission. Full-wave simulations predict a transmission modulation of 95.7% via this mechanism. Experimental measurements reveal a modulation efficiency of 28.6% in transmission at 1,397 cm−1, corresponding to a 2.67-fold improvement over transmission without a metallic slit array. This work paves the way for enhancing light modulation in graphene plasmonics by employing noble metal plasmonic structures. PMID:27499258

  14. Electronically tunable extraordinary optical transmission in graphene plasmonic ribbons coupled to subwavelength metallic slit arrays

    DOE PAGES

    Kim, Seyoon; Jang, Min Seok; Brar, Victor W.; Tolstova, Yulia; Mauser, Kelly W.; Atwater, Harry A.

    2016-08-08

    In this paper, subwavelength metallic slit arrays have been shown to exhibit extraordinary optical transmission, whereby tunneling surface plasmonic waves constructively interfere to create large forward light propagation. The intricate balancing needed for this interference to occur allows for resonant transmission to be highly sensitive to changes in the environment. Here we demonstrate that extraordinary optical transmission resonance can be coupled to electrostatically tunable graphene plasmonic ribbons to create electrostatic modulation of mid-infrared light. Absorption in graphene plasmonic ribbons situated inside metallic slits can efficiently block the coupling channel for resonant transmission, leading to a suppression of transmission. Full-wave simulationsmore » predict a transmission modulation of 95.7% via this mechanism. Experimental measurements reveal a modulation efficiency of 28.6% in transmission at 1,397 cm–1, corresponding to a 2.67-fold improvement over transmission without a metallic slit array. This work paves the way for enhancing light modulation in graphene plasmonics by employing noble metal plasmonic structures.« less

  15. Early development of dynamic shape perception under slit-viewing conditions.

    PubMed

    Imura, Tomoko; Shirai, Nobu

    2014-01-01

    The developmental processes underpinning global shape and global motion perception in infancy have been relatively well described. However, the development of the ability to integrate both global motion and global shape information has remained unclear. In this study we employed a slit-viewing task to investigate the ability to integrate spatiotemporal information among infants ranging in age from 3 to 12 months. In experiment 1 each infant was familiarised with a moving object that was only partly visible through a slit. One of the two objects in the test trial was a novel object, and the other object had appeared previously in familiarisation trials. The findings suggested that infants aged 5 months and over looked longer at the novel drawings compared with the more familiar objects in the test trials. This implies that the infants recognised the whole shape of the object under the slit-viewing condition. In experiment 2 each infant was presented with partial images in a random order. In this case the infants were unable to distinguish the whole shape of the object. The findings suggest that infants did not rely on the local cues provided in experiment .

  16. Virtual Young's Double Slit Experiment for Hard X-ray Photons

    NASA Astrophysics Data System (ADS)

    Isakovic, Abdel; Evans-Lutterodt, K.; Siddons, D. P.; Stein, A.; Warren, J. B.; Sandy, A.; Narayanan, S.; Metzler, M.

    2010-03-01

    Coherent hard X-ray beams underlie many of the recent advances in X-ray imaging and characterization, and it is crucial to quantify the coherence properties of X-ray beams for further advances. The classic Young's double slit experiment is an accepted method from which one can deduce the transverse coherence length, but unfortunately the double slit experiment is difficult to implement at these wavelengths. Micro-fabricated prisms are used to implement a virtual Young's double slit experiment, and interference fringes are quantified by X-ray fluorescence from a 30 nm Cr film in addition to being recorded with YAG crystal and CCD. The maximum number of fringes in the classical overlap region is comparable to δ/4πβ, the ratio of real to imaginary parts of the X-ray refractive index of the prism material. We have measured the horizontal and vertical transverse coherence lengths at beamline APS 8-ID. We suggest this to be a flexible, easily applied method that can be implemented at X-ray laboratories for both, coherence measurements and interferometric imaging. http://arxiv.org/abs/0910.5524

  17. Effects of slits in a patch of omnidirectional Lamb-wave MPT on the transducer output

    NASA Astrophysics Data System (ADS)

    Kim, Kiyean; Lee, Hyung Jin; Lee, Joo Kyung; Kim, Yoon Young

    2016-03-01

    An omnidirectional Lamb-wave magnetostrictive patch transducer (MPT) uses a thin circular magnetostrictive patch excited by the axisymmetric turns of a plane coil placed over it. Since the dynamic magnetic field applied by the coil induces an eddy current only on the top surface due to the skin effect, the mechanical deformation in the patch is confined only near the surface, considerably limiting the transducer output power. This study shows that if a radial slit is introduced in the patch, the circular flow of the eddy current on the top surface only becomes broken, and thus the eddy current flows on both the top and bottom surfaces. As a consequence, there is a substantial increase in the dynamic magnetic field in the patch and, in turn, an increased transducer output power. Interestingly, the material type, either metallic or nonmetallic, of the test waveguide plate affects the magnitude of the eddy current near the bottom surface and the overall magnetic field. If the number of slits is over a certain number, say, 8, and the slits are symmetrically made in the patch, the omni-directivity of the resulting MPT is virtually ensured. Finally, the present findings are verified both numerically and experimentally.

  18. Line-focusing electromagnetic acoustic transducers for the detection of slit defects.

    PubMed

    Ogi, H; Hirao, M; Ohtani, T

    1999-01-01

    This paper describes the design principles of a line-focusing electromagnetic acoustic transducer (LF-EMAT) and the results of a feasibility test for detecting slit-type defects in metals. The LF-EMAT excites shear vertical (SV) elastic waves and focuses them to a line in a metal body. It consists of a permanent magnet block and a meanderline coil, whose spacing is continuously varied so that the excited SV waves become coherent on a focal line after traveling oblique paths. The measured directivity of generation and reception show a sharp peak at the designed focal line. The LF-EMATs are then applied to detecting slit defects in the bottom surface of steel blocks, on which the focal lines are located. Portions of the scattered defect signals are received by the same EMAT. When operated at 4 MHz, the LF-EMATs are capable of detecting slits deeper than 0.05 mm. The sensitivity decreases with liftoff and the LF-EMATs are usable with liftoff up to 0.6 mm. PMID:18238430

  19. Elevated Slit2 Activity Impairs VEGF-induced Angiogenesis and Tumor Neovascularization in EphA2-deficient Endothelium

    PubMed Central

    Youngblood, Victoria; Wang, Shan; Song, Wenqiang; Walter, Debra; Hwang, Yoonha; Chen, Jin; Brantley-Sieders, Dana M.

    2015-01-01

    Angiogenic remodeling during embryonic development and in adult tissue homeostasis is orchestrated by cooperative signaling between several distinct molecular pathways, which are often exploited by tumors. Indeed, tumors upregulate pro-angiogenic molecules while simultaneously suppressing angiostatic pathways in order to recruit blood vessels for growth, survival, and metastatic spread. Understanding how cancers exploit pro- and anti-angiogenic signals is a key step in developing new, molecularly targeted anti-angiogenic therapies. While EphA2, a receptor tyrosine kinase (RTK), is required for vascular endothelial growth factor (VEGF)-induced angiogenesis, the mechanism through which these pathways intersect remains unclear. Slit2 expression is elevated in EphA2-deficient endothelium, and here it is reported that inhibiting Slit activity rescues VEGF-induced angiogenesis in cell culture and in vivo, as well as VEGF-dependent tumor angiogenesis, in EphA2-deficient endothelial cells and animals. Moreover, blocking Slit activity or Slit2 expression in EphA2-deficient endothelial cells restores VEGF-induced activation of Src and Rac, both of which are required for VEGF-mediated angiogenesis. These data suggest that EphA2 suppression of Slit2 expression and Slit angiostatic activity enables VEGF-induced angiogenesis in vitro and in vivo, providing a plausible mechanism for impaired endothelial responses to VEGF in the absence of EphA2 function. PMID:25504371

  20. Sublingual immunotherapy (SLIT)--indications, mechanism, and efficacy: Position paper prepared by the Section of Immunotherapy, Polish Society of Allergy.

    PubMed

    Jutel, Marek; Bartkowiak-Emeryk, Małgorzata; Bręborowicz, Anna; Cichocka-Jarosz, Ewa; Emeryk, Andrzej; Gawlik, Radosław; Gonerko, Paweł; Rogala, Barbara; Nowak-Węgrzyn, Anna; Samoliński, Bolesław

    2016-01-01

    SLIT (sublingual immunotherapy,) induces allergen-specific immune tolerance by sublingual administration of a gradually increasing dose of an allergen. The mechanism of SLIT is comparable to those during SCIT (subcutaneous immunotherapy), with the exception of local oral dendritic cells, pre-programmed to elicit tolerance. In the SLIT dose, to achieve the same efficacy as in SCIT, it should be 50-100 times higher with better safety profile. The highest quality evidence supporting the efficacy of SLIT lasting 1-3 years has been provided by the large scale double-blind, placebo-controlled (DBPC) trials for grass pollen extracts, both in children and adults with allergic rhinitis. Current indications for SLIT are allergic rhinitis (and conjunctivitis) in both children and adults sensitized to pollen allergens (trees, grass, Parietaria), house dust mites (Dermatophagoides pteronyssinus, Dermatophagoides farinae), cat fur, as well as mild to moderate controlled atopic asthma in children sensitized to house dust mites. There are positive findings for both asthma and new sensitization prevention. Severe adverse events, including anaphylaxis, are very rare, and no fatalities have been reported. Local adverse reactions develop in up to 70 - 80% of patients. Risk factors for SLIT adverse events have not been clearly identified. Risk factors of non-adherence to treatment might be dependent on the patient, disease treatment, physician-patient relationship, and variables in the health care system organization. PMID:27012173