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Sample records for video microscopy revealed

  1. Novel aspects of live intestinal epithelial cell function revealed using a custom time-lapse video microscopy apparatus.

    Science.gov (United States)

    Papetti, Michael; Kozlowski, Piotr

    2018-02-06

    Many aspects of cell physiology, including migration, membrane function, and cell division, are best understood by observing live cell dynamics over time using video microscopy. To probe these phenomena in colon epithelial cells using simple components with a limited budget, we have constructed an inexpensive (cells in this system mimic those in a standard tissue culture incubator for over four days. Our system offers significant advantages over existing cost-prohibitive commercially available and custom-made devices because of its very low cost, use of PID temperature control, lack of reliance on constant infusion of external humidified, heated air or carbon dioxide, ability to directly measure cell culture medium temperature, and combination of exquisite cellular detail with minimal focus drift under physiological conditions for extended periods of time. Using this apparatus, coupled with an inverted microscope equipped with phase contrast optics and a programmable digital camera, we have observed many events in colon epithelial cells not visible by static imaging, including kinetics of normal and abnormal mitoses, dynamic membrane structures, intracellular vesicle movements, and cell migration. © 2018 International Society for Advancement of Cytometry. © 2018 International Society for Advancement of Cytometry.

  2. Leica solution: CARS microscopy at video rates

    Science.gov (United States)

    Lurquin, V.

    2008-02-01

    Confocal and multiphoton microscopy are powerful techniques to study morphology and dynamics in cells and tissue, if fluorescent labeling is possible or autofluorescence is strong. For non-fluorescent molecules, Coherent anti-Stokes Raman scattering (CARS) microscopy provides chemical contrast based on intrinsic and highly specific vibrational properties of molecules eliminating the need for labeling. Just as other multiphoton techniques, CARS microscopy possesses three-dimensional sectioning capabilities. Leica Microsystems has combined the CARS imaging technology with its TCS SP5 confocal microscope to provide several advantages for CARS imaging. For CARS microscopy, two picosecond near-infrared lasers are overlapped spatially and temporally and sent into the scanhead of the confocal system. The software allows programmed, automatic switching between these light sources for multi-modal imaging. Furthermore the Leica TCS SP5 can be equipped with a non-descanned detector which will significantly enhance the signal. The Leica TCS SP5 scanhead combines two technologies in one system: a conventional scanner for maximum resolution and a resonant scanner for high time resolution. The fast scanner allows imaging speeds as high as 25 images/per second at a resolution of 512×512 pixel. This corresponds to true video-rate allowing to follow processes at these time-scales as well as the acquisition of three-dimensional stacks in a few seconds. This time resolution is critical to study live animals or human patients for which heart beat and muscle movements lead to a blurring of the image if the acquisition time is high. Furthermore with the resonant scanhead the sectioning is truly confocal and does not suffer from spatial leakage. In summary, CARS microscopy combined with the tandem scanner makes the Leica TCS SP5 a powerful tool for three-dimensional, label-free imaging of chemical and biological samples in vitro and in vivo.

  3. Video rate near-field scanning optical microscopy

    Science.gov (United States)

    Bukofsky, S. J.; Grober, R. D.

    1997-11-01

    The enhanced transmission efficiency of chemically etched near-field optical fiber probes makes it possible to greatly increase the scanning speed of near-field optical microscopes. This increase in system bandwidth allows sub-diffraction limit imaging of samples at video rates. We demonstrate image acquisition at 10 frames/s, rate-limited by mechanical resonances in our scanner. It is demonstrated that the optical signal to noise ratio is large enough for megahertz single pixel acquisition rates.

  4. Lipid Vesicle Shape Analysis from Populations Using Light Video Microscopy and Computer Vision

    OpenAIRE

    Jernej Zupanc; Barbara Drašler; Sabina Boljte; Veronika Kralj-Iglič; Aleš Iglič; Deniz Erdogmus; Damjana Drobne

    2014-01-01

    We present a method for giant lipid vesicle shape analysis that combines manually guided large-scale video microscopy and computer vision algorithms to enable analyzing vesicle populations. The method retains the benefits of light microscopy and enables non-destructive analysis of vesicles from suspensions containing up to several thousands of lipid vesicles (1-50 µm in diameter). For each sample, image analysis was employed to extract data on vesicle quantity and size distributions of their ...

  5. Aggregation and Breakup of Colloidal Particle Aggregates in Shear Flow, Studied with Video Microscopy

    NARCIS (Netherlands)

    Tolpekin, V.A.; Duits, Michael H.G.; van den Ende, Henricus T.M.; Mellema, J.

    2004-01-01

    We used video microscopy to study the behavior of aggregating suspensions in shear flow. Suspensions consisted of 920 nm diameter silica spheres, dispersed in a methanol/bromoform solvent, to which poly(ethylene glycol) (M = 35.000 g) was added to effect weak particle aggregation. With our solvent

  6. Optical tracking of embryonic vertebrates behavioural responses using automated time-resolved video-microscopy system

    Science.gov (United States)

    Walpitagama, Milanga; Kaslin, Jan; Nugegoda, Dayanthi; Wlodkowic, Donald

    2016-12-01

    The fish embryo toxicity (FET) biotest performed on embryos of zebrafish (Danio rerio) has gained significant popularity as a rapid and inexpensive alternative approach in chemical hazard and risk assessment. The FET was designed to evaluate acute toxicity on embryonic stages of fish exposed to the test chemical. The current standard, similar to most traditional methods for evaluating aquatic toxicity provides, however, little understanding of effects of environmentally relevant concentrations of chemical stressors. We postulate that significant environmental effects such as altered motor functions, physiological alterations reflected in heart rate, effects on development and reproduction can occur at sub-lethal concentrations well below than LC10. Behavioral studies can, therefore, provide a valuable integrative link between physiological and ecological effects. Despite the advantages of behavioral analysis development of behavioral toxicity, biotests is greatly hampered by the lack of dedicated laboratory automation, in particular, user-friendly and automated video microscopy systems. In this work we present a proof-of-concept development of an optical system capable of tracking embryonic vertebrates behavioral responses using automated and vastly miniaturized time-resolved video-microscopy. We have employed miniaturized CMOS cameras to perform high definition video recording and analysis of earliest vertebrate behavioral responses. The main objective was to develop a biocompatible embryo positioning structures that were suitable for high-throughput imaging as well as video capture and video analysis algorithms. This system should support the development of sub-lethal and behavioral markers for accelerated environmental monitoring.

  7. Gliding motility of Babesia bovis merozoites visualized by time-lapse video microscopy.

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    Masahito Asada

    Full Text Available BACKGROUND: Babesia bovis is an apicomplexan intraerythrocytic protozoan parasite that induces babesiosis in cattle after transmission by ticks. During specific stages of the apicomplexan parasite lifecycle, such as the sporozoites of Plasmodium falciparum and tachyzoites of Toxoplasma gondii, host cells are targeted for invasion using a unique, active process termed "gliding motility". However, it is not thoroughly understood how the merozoites of B. bovis target and invade host red blood cells (RBCs, and gliding motility has so far not been observed in the parasite. METHODOLOGY/PRINCIPAL FINDINGS: Gliding motility of B. bovis merozoites was revealed by time-lapse video microscopy. The recorded images revealed that the process included egress of the merozoites from the infected RBC, gliding motility, and subsequent invasion into new RBCs. The gliding motility of B. bovis merozoites was similar to the helical gliding of Toxoplasma tachyzoites. The trails left by the merozoites were detected by indirect immunofluorescence assay using antiserum against B. bovis merozoite surface antigen 1. Inhibition of gliding motility by actin filament polymerization or depolymerization indicated that the gliding motility was driven by actomyosin dependent process. In addition, we revealed the timing of breakdown of the parasitophorous vacuole. Time-lapse image analysis of membrane-stained bovine RBCs showed formation and breakdown of the parasitophorous vacuole within ten minutes of invasion. CONCLUSIONS/SIGNIFICANCE: This is the first report of the gliding motility of B. bovis. Since merozoites of Plasmodium parasites do not glide on a substrate, the gliding motility of B. bovis merozoites is a notable finding.

  8. VIPER: a general-purpose digital image-processing system applied to video microscopy.

    Science.gov (United States)

    Brunner, M; Ittner, W

    1988-01-01

    This paper describes VIPER, the video image-processing system Erlangen. It consists of a general purpose microcomputer, commercially available image-processing hardware modules connected directly to the computer, video input/output-modules such as a TV camera, video recorders and monitors, and a software package. The modular structure and the capabilities of this system are explained. The software is user-friendly, menu-driven and performs image acquisition, transfers, greyscale processing, arithmetics, logical operations, filtering display, colour assignment, graphics, and a couple of management functions. More than 100 image-processing functions are implemented. They are available either by typing a key or by a simple call to the function-subroutine library in application programs. Examples are supplied in the area of biomedical research, e.g. in in-vivo microscopy.

  9. Improved depth resolution in video-rate line-scanning multiphoton microscopy using temporal focusing

    Science.gov (United States)

    Tal, Eran; Oron, Dan; Silberberg, Yaron

    2005-07-01

    By introducing spatiotemporal pulse shaping techniques to multiphoton microscopy it is possible to obtain video-rate images with depth resolution similar to point-by-point scanning multiphoton microscopy while mechanically scanning in only one dimension. This is achieved by temporal focusing of the illumination pulse: The pulsed excitation field is compressed as it propagates through the sample, reaching its shortest duration (and highest peak intensity) at the focal plane before stretching again beyond it. This method is applied to produce, in a simple and scalable setup, video-rate two-photon excitation fluorescence images of Drosophila egg chambers with nearly 100,000 effective pixels and 1.5 μm depth resolution.

  10. Dynamics of podosome stiffness revealed by atomic force microscopy

    Science.gov (United States)

    Labernadie, Anna; Thibault, Christophe; Vieu, Christophe; Maridonneau-Parini, Isabelle; Charrière, Guillaume M.

    2010-01-01

    Podosomes are unique cellular entities specifically found in macrophages and involved in cell–matrix interactions, matrix degradation, and 3D migration. They correspond to a core of F-actin surrounded at its base by matrix receptors. To investigate the structure/function relationships of podosomes, soft lithography, atomic force microscopy (AFM), and correlative fluorescence microscopy were used to characterize podosome physical properties in macrophages differentiated from human blood monocytes. Podosome formation was restricted to delineated areas with micropatterned fibrinogen to facilitate AFM analyses. Podosome height and stiffness were measured with great accuracy in living macrophages (578 ± 209 nm and 43.8 ± 9.3 kPa) and these physical properties were independent of the nature of the underlying matrix. In addition, time-lapse AFM revealed that podosomes harbor two types of overlapping periodic stiffness variations throughout their lifespan, which depend on F-actin and myosin II activity. This report shows that podosome biophysical properties are amenable to AFM, allowing the study of podosomes in living macrophages at nanoscale resolution and the analysis of their intimate dynamics. Such an approach opens up perspectives to better understand the mechanical functionality of podosomes under physiological and pathological contexts. PMID:21081699

  11. Synchronous-digitization for Video Rate Polarization Modulated Beam Scanning Second Harmonic Generation Microscopy.

    Science.gov (United States)

    Sullivan, Shane Z; DeWalt, Emma L; Schmitt, Paul D; Muir, Ryan M; Simpson, Garth J

    2015-03-09

    Fast beam-scanning non-linear optical microscopy, coupled with fast (8 MHz) polarization modulation and analytical modeling have enabled simultaneous nonlinear optical Stokes ellipsometry (NOSE) and linear Stokes ellipsometry imaging at video rate (15 Hz). NOSE enables recovery of the complex-valued Jones tensor that describes the polarization-dependent observables, in contrast to polarimetry, in which the polarization stated of the exciting beam is recorded. Each data acquisition consists of 30 images (10 for each detector, with three detectors operating in parallel), each of which corresponds to polarization-dependent results. Processing of this image set by linear fitting contracts down each set of 10 images to a set of 5 parameters for each detector in second harmonic generation (SHG) and three parameters for the transmittance of the fundamental laser beam. Using these parameters, it is possible to recover the Jones tensor elements of the sample at video rate. Video rate imaging is enabled by performing synchronous digitization (SD), in which a PCIe digital oscilloscope card is synchronized to the laser (the laser is the master clock.) Fast polarization modulation was achieved by modulating an electro-optic modulator synchronously with the laser and digitizer, with a simple sine-wave at 1/10th the period of the laser, producing a repeating pattern of 10 polarization states. This approach was validated using Z-cut quartz, and NOSE microscopy was performed for micro-crystals of naproxen.

  12. Synchronous-digitization for video rate polarization modulated beam scanning second harmonic generation microscopy

    Science.gov (United States)

    Sullivan, Shane Z.; DeWalt, Emma L.; Schmitt, Paul D.; Muir, Ryan D.; Simpson, Garth J.

    2015-03-01

    Fast beam-scanning non-linear optical microscopy, coupled with fast (8 MHz) polarization modulation and analytical modeling have enabled simultaneous nonlinear optical Stokes ellipsometry (NOSE) and linear Stokes ellipsometry imaging at video rate (15 Hz). NOSE enables recovery of the complex-valued Jones tensor that describes the polarization-dependent observables, in contrast to polarimetry, in which the polarization stated of the exciting beam is recorded. Each data acquisition consists of 30 images (10 for each detector, with three detectors operating in parallel), each of which corresponds to polarization-dependent results. Processing of this image set by linear fitting contracts down each set of 10 images to a set of 5 parameters for each detector in second harmonic generation (SHG) and three parameters for the transmittance of the fundamental laser beam. Using these parameters, it is possible to recover the Jones tensor elements of the sample at video rate. Video rate imaging is enabled by performing synchronous digitization (SD), in which a PCIe digital oscilloscope card is synchronized to the laser (the laser is the master clock.) Fast polarization modulation was achieved by modulating an electro-optic modulator synchronously with the laser and digitizer, with a simple sine-wave at 1/10th the period of the laser, producing a repeating pattern of 10 polarization states. This approach was validated using Z-cut quartz, and NOSE microscopy was performed for micro-crystals of naproxen.

  13. Removing the effect of blooming from potential energy measurement by employing total internal reflection microscopy integrated with video microscopy.

    Science.gov (United States)

    Cao, Feng; Gong, Xiangjun; He, Chuanxin; Ngai, To

    2017-10-01

    Total internal reflection microscopy (TIRM) measures the interactions between a colloidal particle and a flat surface in aqueous solution. Recently, TIRM has further integrated with video microscopy (VM) and enabled the simultaneous measurements of multi-particle colloid-surface interactions in the same ensemble. However, there still remain challenges about accurate image acquisition due to blooming. Blooming means the number of photons reaching the detector exceeds its maximum capacity, and the excess photons will either spill to adjacent pixels or not be counted, leading to an obstacle from precise determination of intensity. Our result shows that blooming gives rise to a deviation of the measured potential energy from the classical theory of Derjaguin, Landau, Verway, and Overbeek (DLVO). Therefore, a correction method was developed in this work to deduce the real intensity from the experimental measurement. The relationship between scattered light intensity and exposure time deviates from linearity when blooming occurs. A correction equation was developed to recover the real intensity, which was then confirmed by the accordance between the corresponding potential energy profiles and the DLVO theory. This correction method is suitable for VM systems of colloidal probes illuminated by scattered light, broadening the application of VM imaging to investigate colloidal interactions. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Observation of photodynamically-induced cell destruction probed by video microscopy, laser-scanning microscopy, and fluorescence spectroscopy

    Science.gov (United States)

    Rueck, Angelika C.; Strauss, Wolfgang S. L.; Gschwend, Michael H.; Koenig, Karsten; Brunner, B.; Schneckenburger, Herbert; Walt, Heinrich; Steiner, Rudolf W.

    1993-07-01

    In order to study light-induced reactions during PDT, the fluorescence response of the photosensitizer meso-tetra(4-sulfonatophenyl)porphyrin (TPPS4) was observed in different cell systems and correlated with the sensitivity to photodynamic induced destructions. RR 1022 epithelial cells from the rat were grown on microscopic slides at a high and low cell density. Using video microscopy in combination with microspectrofluorometry we observed a different fluorescence behavior for high and low cell conditions during light exposure. A fluorescence relocalization from the cytoplasm to the nucleus and an intensity increase-- correlated with the formation of a new molecular species--could be detected only for low cell density. Moreover, cell cultures at a high density showed to be less sensitive to photodynamic destructions. In addition to cell culture-experiments, we observed the light-induced reactions of TPPS4 accumulated in multicellular tumor spheroids. For these measurements laser scanning microscopy was used. Fluorescence relocalization and intensity increase could be detected only for the peripheric parts of the spheroids. The different fluorescence response seems to reflect different metabolic and physiologic states of the cells.

  15. Lipid vesicle shape analysis from populations using light video microscopy and computer vision.

    Directory of Open Access Journals (Sweden)

    Jernej Zupanc

    Full Text Available We present a method for giant lipid vesicle shape analysis that combines manually guided large-scale video microscopy and computer vision algorithms to enable analyzing vesicle populations. The method retains the benefits of light microscopy and enables non-destructive analysis of vesicles from suspensions containing up to several thousands of lipid vesicles (1-50 µm in diameter. For each sample, image analysis was employed to extract data on vesicle quantity and size distributions of their projected diameters and isoperimetric quotients (measure of contour roundness. This process enables a comparison of samples from the same population over time, or the comparison of a treated population to a control. Although vesicles in suspensions are heterogeneous in sizes and shapes and have distinctively non-homogeneous distribution throughout the suspension, this method allows for the capture and analysis of repeatable vesicle samples that are representative of the population inspected.

  16. Application Of Digitized Fluorescence Microscopy And Video Photobleaching To Study Membrane Dynamics During Cell Locomotion

    Science.gov (United States)

    Jacobson, Kenneth A.; Ishihara, A.; Holifield, B.; Lee, J.

    1989-12-01

    Our laboratory is concerned with understanding the dynamic structure of the plasma membrane with particular reference to the movement of membrane constituents during cell locomotion. We employ digitized fluorescence microscopy (DFM) alone or in combination with fluorescence recovery after photobleaching (FRAP) to investigate individual cells. DFM is really a new form of light microscopy in that the distribution of individual classes of ions, molecules, and macromolecules can be followed in single, living cells. By employing fluorescent antibodies to define antigens or fluorescent analogs of cellular constituents as well as ultra-sensitive, electronic image detectors and video image averaging to improve signal to noise, fluorescent images of living cells can be acquired over an extended period without significant fading and loss of cell viability. FRAP allows the measurement of translational mobility of membrane and cytoplasmic molecules in small regions of single, living cells.

  17. In vivo multimodality video microscopy of human skin in the vertical plane (Conference Presentation)

    Science.gov (United States)

    Wu, Zhenguo; Tian, Yunxian; Zhao, Jianhua; Lui, Harvey; McLean, David I.; Zeng, Haishan

    2016-02-01

    Reflectance confocal microscopy (RCM) and multiphoton microscopy (MPM) are non-invasive methods of acquiring morphological images of the skin in vivo. Most research in this area focuses on instruments that are configured for two-dimensional imaging in a horizontal plane parallel to the skin surface. In contrast, conventional histopathologic evaluation of the skin is based on vertical tissue sections that show microscopic features and their interrelationships according to their depth within the skin. The ability to similarly depict the skin in the vertical plane during in vivo microscopic imaging poses several significant challenges with respect to imaging speed, resolution and extractable information. Aiming to address above challenges, we developed a laser scanning multimodal microscopy system which combines RCM and MPM, and has the ability to do fast xz scanning to achieve high resolution vertical "optical sectioning" of in vivo human skin at video rates. RCM and MPM images are obtained simultaneously and co-registered thereby providing complementary morphological information. To validate the performance of this system vertical section RCM and MPM microscopic images of normal human skin in vivo were obtained at half video rates (15 frames/s). Using our system it is possible to discern the following structures: all layers of the epidermis including the stratum lucidum, the dermal-epidermal junction, and the papillary dermis. Blood flow is also visible as evidenced by blood cell movement within vessels. The effective imaging depth is about 200 micrometers. This system provides a means of interrogating human skin noninvasively at an orientation analogous to conventional histological sectioning.

  18. Scanning electron microscopy of Dermatobia hominis reveals cutaneous anchoring features.

    Science.gov (United States)

    Möhrenschlager, Matthias; Mempel, Martin; Weichenmeier, Ingrid; Engst, Reinhard; Ring, Johannnes; Behrendt, Heidrun

    2007-10-01

    We report the case of a 45-year-old Caucasian woman suffering from cutaneous myiasis. With the use of scanning electron microscopy, we placed special focus on the mechanisms by which Dermatobia hominis can fasten securely within the human skin.

  19. Super-resolution microscopy reveals compartmentalization of peroxisomal membrane proteins

    DEFF Research Database (Denmark)

    Galiani, Silvia; Waithe, Dominic; Reglinski, Katharina

    2016-01-01

    the use of super-resolution optical stimulated emission depletion microscopy to investigate with sub-60-nm resolution the heterogeneous spatial organization of the peroxisomal proteins PEX5, PEX14, and PEX11 around actively importing peroxisomes, showing distinct differences between these peroxins......Membrane-associated events during peroxisomal protein import processes play an essential role in peroxisome functionality. Many details of these processes are not known due to missing spatial resolution of technologies capable of investigating peroxisomes directly in the cell. Here, we present...

  20. Video-rate processing in tomographic phase microscopy of biological cells using CUDA.

    Science.gov (United States)

    Dardikman, Gili; Habaza, Mor; Waller, Laura; Shaked, Natan T

    2016-05-30

    We suggest a new implementation for rapid reconstruction of three-dimensional (3-D) refractive index (RI) maps of biological cells acquired by tomographic phase microscopy (TPM). The TPM computational reconstruction process is extremely time consuming, making the analysis of large data sets unreasonably slow and the real-time 3-D visualization of the results impossible. Our implementation uses new phase extraction, phase unwrapping and Fourier slice algorithms, suitable for efficient CPU or GPU implementations. The experimental setup includes an external off-axis interferometric module connected to an inverted microscope illuminated coherently. We used single cell rotation by micro-manipulation to obtain interferometric projections from 73 viewing angles over a 180° angular range. Our parallel algorithms were implemented using Nvidia's CUDA C platform, running on Nvidia's Tesla K20c GPU. This implementation yields, for the first time to our knowledge, a 3-D reconstruction rate higher than video rate of 25 frames per second for 256 × 256-pixel interferograms with 73 different projection angles (64 × 64 × 64 output). This allows us to calculate additional cellular parameters, while still processing faster than video rate. This technique is expected to find uses for real-time 3-D cell visualization and processing, while yielding fast feedback for medical diagnosis and cell sorting.

  1. Resinless section electron microscopy reveals the yeast cytoskeleton.

    Science.gov (United States)

    Penman, J; Penman, S

    1997-04-15

    The cytoskeleton of Saccharomyces cerevisiae is essentially invisible using conventional microscopy techniques. A similar problem was solved for the mammalian cell cytoskeleton using resinless section electron microscopy, a technique applied here to yeast. In the resinless image, soluble proteins are no longer cloaked by embedding medium and must be removed by selective detergent extraction. In yeast, this requires breaching the cell wall by digesting with Zymolyase sufficiently to allow detergent extraction of the plasma membrane lipids. Gel electropherograms show that the extracted or "soluble" proteins are distinct from the retained or "structural" proteins that presumably comprise the cytoskeleton. These putative cytoskeleton proteins include the major portions of a 43-kDa protein, which is presumably actin, and of proteins in a band appearing at 55 kDa, as well as numerous less abundant, nonactin proteins. Resinless section electron micrographs show a dense, three-dimensional web of anastomosing, polymorphic filaments bounded by the remnant cell wall. Although the filament network is very heterogenous, there appear to be two principal classes of filament diameters-5 nm and 15-20 nm-which may correspond to actin and intermediate filaments, respectively. A large oval region of lower filament density probably corresponds to the vacuole, and an electron dense spheroidal body, 300-500 nm in diameter, is likely the nucleus. The techniques detailed in this report afford new approaches to the study of yeast cytoarchitecture.

  2. Automatic tracking of cells for video microscopy in patch clamp experiments.

    Science.gov (United States)

    Peixoto, Helton M; Munguba, Hermany; Cruz, Rossana M S; Guerreiro, Ana M G; Leao, Richardson N

    2014-06-20

    Visualisation of neurons labeled with fluorescent proteins or compounds generally require exposure to intense light for a relatively long period of time, often leading to bleaching of the fluorescent probe and photodamage of the tissue. Here we created a technique to drastically shorten light exposure and improve the targeting of fluorescent labeled cells that is specially useful for patch-clamp recordings. We applied image tracking and mask overlay to reduce the time of fluorescence exposure and minimise mistakes when identifying neurons. Neurons are first identified according to visual criteria (e.g. fluorescence protein expression, shape, viability etc.) and a transmission microscopy image Differential Interference Contrast (DIC) or Dodt contrast containing the cell used as a reference for the tracking algorithm. A fluorescence image can also be acquired later to be used as a mask (that can be overlaid on the target during live transmission video). As patch-clamp experiments require translating the microscope stage, we used pattern matching to track reference neurons in order to move the fluorescence mask to match the new position of the objective in relation to the sample. For the image processing we used the Open Source Computer Vision (OpenCV) library, including the Speeded-Up Robust Features (SURF) for tracking cells. The dataset of images (n = 720) was analyzed under normal conditions of acquisition and with influence of noise (defocusing and brightness). We validated the method in dissociated neuronal cultures and fresh brain slices expressing Enhanced Yellow Fluorescent Protein (eYFP) or Tandem Dimer Tomato (tdTomato) proteins, which considerably decreased the exposure to fluorescence excitation, thereby minimising photodamage. We also show that the neuron tracking can be used in differential interference contrast or Dodt contrast microscopy. The techniques of digital image processing used in this work are an important addition to the set of microscopy

  3. Local characterization of hindered Brownian motion by using digital video microscopy and 3D particle tracking

    Energy Technology Data Exchange (ETDEWEB)

    Dettmer, Simon L.; Keyser, Ulrich F.; Pagliara, Stefano [Cavendish Laboratory, University of Cambridge, 19 J J Thomson Avenue, Cambridge CB3 0HE (United Kingdom)

    2014-02-15

    In this article we present methods for measuring hindered Brownian motion in the confinement of complex 3D geometries using digital video microscopy. Here we discuss essential features of automated 3D particle tracking as well as diffusion data analysis. By introducing local mean squared displacement-vs-time curves, we are able to simultaneously measure the spatial dependence of diffusion coefficients, tracking accuracies and drift velocities. Such local measurements allow a more detailed and appropriate description of strongly heterogeneous systems as opposed to global measurements. Finite size effects of the tracking region on measuring mean squared displacements are also discussed. The use of these methods was crucial for the measurement of the diffusive behavior of spherical polystyrene particles (505 nm diameter) in a microfluidic chip. The particles explored an array of parallel channels with different cross sections as well as the bulk reservoirs. For this experiment we present the measurement of local tracking accuracies in all three axial directions as well as the diffusivity parallel to the channel axis while we observed no significant flow but purely Brownian motion. Finally, the presented algorithm is suitable also for tracking of fluorescently labeled particles and particles driven by an external force, e.g., electrokinetic or dielectrophoretic forces.

  4. Video-frequency scanning transmission electron microscopy of moving gold nanoparticles in liquid.

    Science.gov (United States)

    Ring, Elisabeth A; de Jonge, Niels

    2012-11-01

    Immobilized gold nanoparticles were imaged in a liquid containing water and 50% glycerol with scanning transmission electron microscopy (STEM). The specimen was enclosed in a liquid compartment formed by two silicon microchips with electron transparent windows. A series of images was recorded at video frequency with a spatial resolution of 1.5nm. The nanoparticles detached from their support after imaging them for several seconds at a magnification of 250,000. Their movement was found to be much different than the movement of nanoparticles moving freely in liquid as described by Brownian Motion. The direction of motion was not random-the nanoparticles moved either in a preferred direction, or radially outwards from the center of the image. The displacement of the gold nanoparticles over time was three orders of magnitude smaller than expected on the basis of Brownian Motion. This finding implies that nanoscale objects of flexible structure or freely floating, including nanoparticles and biological objects, can be imaged with nanoscale resolution, as long as they are in close proximity to a solid support structure. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. A Filtering Method to Reveal Crystalline Patterns from Atom Probe Microscopy Desorption Maps

    Science.gov (United States)

    2016-03-26

    reveal crystalline patterns from atom probe microscopy desorption maps Lan Yao Department of Materials Science and Engineering, University of Michigan, Ann...reveal the crystallographic information present in Atom Probe Microscopy (APM) data is presented. Themethod filters atoms based on the time difference...between their evaporation and the evaporation of the previous atom . Since this time difference correlates with the location and the local structure of

  6. Correlative atomic force microscopy and localization-based super-resolution microscopy: revealing labelling and image reconstruction artefacts.

    Science.gov (United States)

    Monserrate, Aitor; Casado, Santiago; Flors, Cristina

    2014-03-17

    Hybrid microscopy: A correlative microscopy tool that combines in situ super-resolution fluorescence microscopy based on single-molecule localization and atomic force microscopy is presented. Direct comparison with high- resolution topography allows the authors to improve fluorescence labeling and image analysis in super-resolution imaging. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Homogeneous vs heterogeneous polymerization catalysis revealed by single-particle fluorescence microscopy.

    Science.gov (United States)

    Esfandiari, N Melody; Blum, Suzanne A

    2011-11-16

    A high-sensitivity and high-resolution single-particle fluorescence microscopy technique differentiated between homogeneous and heterogeneous metathesis polymerization catalysis by imaging the location of the early stages of polymerization. By imaging single polymers and single crystals of Grubbs II, polymerization catalysis was revealed to be solely homogeneous rather than heterogeneous or both.

  8. Towards an automated analysis of video-microscopy images of fungal morphogenesis

    Directory of Open Access Journals (Sweden)

    Diéguez-Uribeondo, Javier

    2005-06-01

    Full Text Available Fungal morphogenesis is an exciting field of cell biology and several mathematical models have been developed to describe it. These models require experimental evidences to be corroborated and, therefore, there is a continuous search for new microscopy and image analysis techniques. In this work, we have used a Canny-edge-detector based technique to automate the generation of hyphal profiles and calculation of morphogenetic parameters such as diameter, elongation rates and hyphoid fitness. The results show that the data obtained with this technique are similar to published data generated with manualbased tracing techniques and that have been carried out on the same species or genus. Thus, we show that application of edge detector-based technique to hyphal growth represents an efficient and accurate method to study hyphal morphogenesis. This represents the first step towards an automated analysis of videomicroscopy images of fungal morphogenesis.La morfogénesis de los hongos es un área de estudio de gran relevancia en la biología celular y en la que se han desarrollado varios modelos matemáticos. Los modelos matemáticos de procesos biológicos precisan de pruebas experimentales que apoyen y corroboren las predicciones teóricas y, por este motivo, existe una búsqueda continua de nuevas técnicas de microscopía y análisis de imágenes para su aplicación en el estudio del crecimiento celular. En este trabajo hemos utilizado una técnica basada en un detector de contornos llamado “Canny-edge-detectorâ€� con el objetivo de automatizar la generación de perfiles de hifas y el cálculo de parámetros morfogenéticos, tales como: el diámetro, la velocidad de elongación y el ajuste con el perfil hifoide, es decir, el perfil teórico de las hifas de los hongos. Los resultados obtenidos son similares a los datos publicados a partir de técnicas manuales de trazado de contornos, generados en la misma especie y género. De esta manera

  9. Video-mosaicking of in vivo reflectance confocal microscopy images for noninvasive examination of skin lesion (Conference Presentation)

    Science.gov (United States)

    Kose, Kivanc; Gou, Mengran; Yelamos, Oriol; Cordova, Miguel A.; Rossi, Anthony; Nehal, Kishwer S.; Camps, Octavia I.; Dy, Jennifer G.; Brooks, Dana H.; Rajadhyaksha, Milind

    2017-02-01

    In this report we describe a computer vision based pipeline to convert in-vivo reflectance confocal microscopy (RCM) videos collected with a handheld system into large field of view (FOV) mosaics. For many applications such as imaging of hard to access lesions, intraoperative assessment of MOHS margins, or delineation of lesion margins beyond clinical borders, raster scan based mosaicing techniques have clinically significant limitations. In such cases, clinicians often capture RCM videos by freely moving a handheld microscope over the area of interest, but the resulting videos lose large-scale spatial relationships. Videomosaicking is a standard computational imaging technique to register, and stitch together consecutive frames of videos into large FOV high resolution mosaics. However, mosaicing RCM videos collected in-vivo has unique challenges: (i) tissue may deform or warp due to physical contact with the microscope objective lens, (ii) discontinuities or "jumps" between consecutive images and motion blur artifacts may occur, due to manual operation of the microscope, and (iii) optical sectioning and resolution may vary between consecutive images due to scattering and aberrations induced by changes in imaging depth and tissue morphology. We addressed these challenges by adapting or developing new algorithmic methods for videomosaicking, specifically by modeling non-rigid deformations, followed by automatically detecting discontinuities (cut locations) and, finally, applying a data-driven image stitching approach that fully preserves resolution and tissue morphologic detail without imposing arbitrary pre-defined boundaries. We will present example mosaics obtained by clinical imaging of both melanoma and non-melanoma skin cancers. The ability to combine freehand mosaicing for handheld microscopes with preserved cellular resolution will have high impact application in diverse clinical settings, including low-resource healthcare systems.

  10. Third-harmonic generation microscopy reveals dental anatomy in ancient fossils.

    Science.gov (United States)

    Chen, Yu-Cheng; Lee, Szu-Yu; Wu, Yana; Brink, Kirstin; Shieh, Dar-Bin; Huang, Timothy D; Reisz, Robert R; Sun, Chi-Kuang

    2015-04-01

    Fossil teeth are primary tools in the study of vertebrate evolution, but standard imaging modalities have not been capable of providing high-quality images in dentin, the main component of teeth, owing to small refractive index differences in the fossilized dentin. Our first attempt to use third-harmonic generation (THG) microscopy in fossil teeth has yielded significant submicrometer level anatomy, with an unexpectedly strong signal contrasting fossilized tubules from the surrounding dentin. Comparison between fossilized and extant teeth of crocodilians reveals a consistent evolutionary signature through time, indicating the great significance of THG microscopy in the evolutionary studies of dental anatomy in fossil teeth.

  11. A method to validate quantitative high-frequency power doppler ultrasound with fluorescence in vivo video microscopy.

    Science.gov (United States)

    Pinter, Stephen Z; Kim, Dae-Ro; Hague, M Nicole; Chambers, Ann F; MacDonald, Ian C; Lacefield, James C

    2014-08-01

    Flow quantification with high-frequency (>20 MHz) power Doppler ultrasound can be performed objectively using the wall-filter selection curve (WFSC) method to select the cutoff velocity that yields a best-estimate color pixel density (CPD). An in vivo video microscopy system (IVVM) is combined with high-frequency power Doppler ultrasound to provide a method for validation of CPD measurements based on WFSCs in mouse testicular vessels. The ultrasound and IVVM systems are instrumented so that the mouse remains on the same imaging platform when switching between the two modalities. In vivo video microscopy provides gold-standard measurements of vascular diameter to validate power Doppler CPD estimates. Measurements in four image planes from three mice exhibit wide variation in the optimal cutoff velocity and indicate that a predetermined cutoff velocity setting can introduce significant errors in studies intended to quantify vascularity. Consistent with previously published flow-phantom data, in vivo WFSCs exhibited three characteristic regions and detectable plateaus. Selection of a cutoff velocity at the right end of the plateau yielded a CPD close to the gold-standard vascular volume fraction estimated using IVVM. An investigator can implement the WFSC method to help adapt cutoff velocity to current blood flow conditions and thereby improve the accuracy of power Doppler for quantitative microvascular imaging. Copyright © 2014 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  12. Microscopy

    Science.gov (United States)

    Patricia A. Moss; Les Groom

    2001-01-01

    Microscopy is the study and interpretation of images produced by a microscope. "Interpretation" is the keyword, because the microscope enables one to see structures that are too small or too close together to be resolved by the unaided eye. (The human eye cannot separate two points or lines that are closer together than 0.1 mm.) it is important to...

  13. Morphology and structure of lipoproteins revealed by an optimized negative-staining protocol of electron microscopy[S

    Science.gov (United States)

    Zhang, Lei; Song, James; Cavigiolio, Giorgio; Ishida, Brian Y.; Zhang, Shengli; Kane, John P.; Weisgraber, Karl H.; Oda, Michael N.; Rye, Kerry-Anne; Pownall, Henry J.; Ren, Gang

    2011-01-01

    Plasma lipoprotein levels are predictors of risk for coronary artery disease. Lipoprotein structure-function relationships provide important clues that help identify the role of lipoproteins in cardiovascular disease. The compositional and conformational heterogeneity of lipoproteins are major barriers to the identification of their structures, as discovered using traditional approaches. Although electron microscopy (EM) is an alternative approach, conventional negative staining (NS) produces rouleau artifacts. In a previous study of apolipoprotein (apo)E4-containing reconstituted HDL (rHDL) particles, we optimized the NS method in a way that eliminated rouleaux. Here we report that phosphotungstic acid at high buffer salt concentrations plays a key role in rouleau formation. We also validate our protocol for analyzing the major plasma lipoprotein classes HDL, LDL, IDL, and VLDL, as well as homogeneously prepared apoA-I-containing rHDL. High-contrast EM images revealed morphology and detailed structures of lipoproteins, especially apoA-I-containing rHDL, that are amenable to three-dimensional reconstruction by single-particle analysis and electron tomography. PMID:20978167

  14. Biological reactivity of nanoparticles: mosaics from optical microscopy videos of giant lipid vesicles

    Science.gov (United States)

    Zupanc, Jernej; Dobnikar, Andrej; Drobne, Damjana; Valant, Janez; Erdogmus, Deniz; Bas, Erhan

    2011-02-01

    Emerging fields such as nanomedicine and nanotoxicology, demand new information on the effects of nanoparticles on biological membranes and lipid vesicles are suitable as an experimental model for bio-nano interaction studies. This paper describes image processing algorithms which stitch video sequences into mosaics and recording the shapes of thousands of lipid vesicles, which were used to assess the effect of CoFe2O4 nanoparticles on the population of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine lipid vesicles. The applicability of this methodology for assessing the potential of engineered nanoparticles to affect morphological properties of lipid membranes is discussed.

  15. Quantitative multicolor super-resolution microscopy reveals tetherin HIV-1 interaction.

    Directory of Open Access Journals (Sweden)

    Martin Lehmann

    2011-12-01

    Full Text Available Virus assembly and interaction with host-cell proteins occur at length scales below the diffraction limit of visible light. Novel super-resolution microscopy techniques achieve nanometer resolution of fluorescently labeled molecules. The cellular restriction factor tetherin (also known as CD317, BST-2 or HM1.24 inhibits the release of human immunodeficiency virus 1 (HIV-1 through direct incorporation into viral membranes and is counteracted by the HIV-1 protein Vpu. For super-resolution analysis of HIV-1 and tetherin interactions, we established fluorescence labeling of HIV-1 proteins and tetherin that preserved HIV-1 particle formation and Vpu-dependent restriction, respectively. Multicolor super-resolution microscopy revealed important structural features of individual HIV-1 virions, virus assembly sites and their interaction with tetherin at the plasma membrane. Tetherin localization to micro-domains was dependent on both tetherin membrane anchors. Tetherin clusters containing on average 4 to 7 tetherin dimers were visualized at HIV-1 assembly sites. Combined biochemical and super-resolution analysis revealed that extended tetherin dimers incorporate both N-termini into assembling virus particles and restrict HIV-1 release. Neither tetherin domains nor HIV-1 assembly sites showed enrichment of the raft marker GM1. Together, our super-resolution microscopy analysis of HIV-1 interactions with tetherin provides new insights into the mechanism of tetherin-mediated HIV-1 restriction and paves the way for future studies of virus-host interactions.

  16. Revealing 3D Ultrastructure and Morphology of Stem Cell Spheroids by Electron Microscopy.

    Science.gov (United States)

    Jaros, Josef; Petrov, Michal; Tesarova, Marketa; Hampl, Ales

    2017-01-01

    Cell culture methods have been developed in efforts to produce biologically relevant systems for developmental and disease modeling, and appropriate analytical tools are essential. Knowledge of ultrastructural characteristics represents the basis to reveal in situ the cellular morphology, cell-cell interactions, organelle distribution, niches in which cells reside, and many more. The traditional method for 3D visualization of ultrastructural components, serial sectioning using transmission electron microscopy (TEM), is very labor-intensive due to contentious TEM slice preparation and subsequent image processing of the whole collection. In this chapter, we present serial block-face scanning electron microscopy, together with complex methodology for spheroid formation, contrasting of cellular compartments, image processing, and 3D visualization. The described technique is effective for detailed morphological analysis of stem cell spheroids, organoids, as well as organotypic cell cultures.

  17. Type 1 diabetes mellitus effects on dental enamel formation revealed by microscopy and microanalysis.

    Science.gov (United States)

    Silva, Bruna Larissa Lago; Medeiros, Danila Lima; Soares, Ana Prates; Line, Sérgio Roberto Peres; Pinto, Maria das Graças Farias; Soares, Telma de Jesus; do Espírito Santo, Alexandre Ribeiro

    2017-12-14

    Type 1 diabetes mellitus (T1DM) largely affects children, occurring therefore at the same period of deciduous and permanent teeth development. The aim of this work was to investigate birefringence and morphology of the secretory stage enamel organic extracellular matrix (EOECM), and structural and mechanical features of mature enamel from T1DM rats. Adult Wistar rats were maintained alive for a period of 56 days after the induction of experimental T1DM with a single dose of streptozotocin (60 mg/kg). After proper euthanasia of the animals, fixed upper incisors were accurately processed, and secretory stage EOECM and mature enamel were analyzed by transmitted polarizing and bright field light microscopies (TPLM and BFLM), energy-dispersive x-ray (EDX) analysis, scanning electron microscopy (SEM), and microhardness testing. Bright field light microscopies and transmitted polarizing light microscopies showed slight morphological changes in the secretory stage EOECM from diabetic rats, which also did not exhibit statistically significant alterations in birefringence brightness when compared to control animals (P > .05). EDX analysis showed that T1DM induced statistically significant little increases in the amount of calcium and phosphorus in outer mature enamel (P  .05). T1DM also caused important ultrastructural alterations in mature enamel as revealed by SEM and induced a statistically significant reduction of about 13.67% in its microhardness at 80 μm from dentin-enamel junction (P enamel development, leading to alterations in mature enamel ultrastructure and in its mechanical features. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  18. Atomic force microscopy reveals hydroxyapatite-citrate interfacial structure at the atomic level.

    Science.gov (United States)

    Jiang, Wenge; Pan, Haihua; Cai, Yurong; Tao, Jinhui; Liu, Peng; Xu, Xurong; Tang, Ruikang

    2008-11-04

    An approach to organic-inorganic interfacial structure at the atomic level is a great challenge in the studies of biomineralization. We demonstrate that atomic force microscopy (AFM) is powerful tool to discover the biomineral interface in detail. By using a model system of (100) hydroxyapatite (HAP) face and citrate, it reveals experimentally that only a side carboxylate and a surface calcium ion are involved in the binding effect during the citrate adsorption, which is against the previous understandings by using Langmuir adsorption and computer simulation. Furthermore, the adsorbed citrate molecules can use their free carboxylate and hydroxyl groups to be self-assembled on the HAP surface. AFM examination also finds that the presence of citrate molecules on the HAP crystal faces can enhance the adhesion force of the HAP surface. We suggest that the established AFM method can be used for a precise and direct understanding of biointerfaces at the atomic level.

  19. Atomic structure of sensitive battery materials and interfaces revealed by cryo-electron microscopy.

    Science.gov (United States)

    Li, Yuzhang; Li, Yanbin; Pei, Allen; Yan, Kai; Sun, Yongming; Wu, Chun-Lan; Joubert, Lydia-Marie; Chin, Richard; Koh, Ai Leen; Yu, Yi; Perrino, John; Butz, Benjamin; Chu, Steven; Cui, Yi

    2017-10-27

    Whereas standard transmission electron microscopy studies are unable to preserve the native state of chemically reactive and beam-sensitive battery materials after operation, such materials remain pristine at cryogenic conditions. It is then possible to atomically resolve individual lithium metal atoms and their interface with the solid electrolyte interphase (SEI). We observe that dendrites in carbonate-based electrolytes grow along the (preferred), , or directions as faceted, single-crystalline nanowires. These growth directions can change at kinks with no observable crystallographic defect. Furthermore, we reveal distinct SEI nanostructures formed in different electrolytes. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  20. Helium ion microscopy and ultra-high-resolution scanning electron microscopy analysis of membrane-extracted cells reveals novel characteristics of the cytoskeleton of Giardia intestinalis.

    Science.gov (United States)

    Gadelha, Ana Paula Rocha; Benchimol, Marlene; de Souza, Wanderley

    2015-06-01

    Giardia intestinalis presents a complex microtubular cytoskeleton formed by specialized structures, such as the adhesive disk, four pairs of flagella, the funis and the median body. The ultrastructural organization of the Giardia cytoskeleton has been analyzed using different microscopic techniques, including high-resolution scanning electron microscopy. Recent advances in scanning microscopy technology have opened a new venue for the characterization of cellular structures and include scanning probe microscopy techniques such as ultra-high-resolution scanning electron microscopy (UHRSEM) and helium ion microscopy (HIM). Here, we studied the organization of the cytoskeleton of G. intestinalis trophozoites using UHRSEM and HIM in membrane-extracted cells. The results revealed a number of new cytoskeletal elements associated with the lateral crest and the dorsal surface of the parasite. The fine structure of the banded collar was also observed. The marginal plates were seen linked to a network of filaments, which were continuous with filaments parallel to the main cell axis. Cytoplasmic filaments that supported the internal structures were seen by the first time. Using anti-actin antibody, we observed a labeling in these filamentous structures. Taken together, these data revealed new surface characteristics of the cytoskeleton of G. intestinalis and may contribute to an improved understanding of the structural organization of trophozoites. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Oral astringent stimuli alter the enamel pellicle's ultrastructure as revealed by electron microscopy.

    Science.gov (United States)

    Rehage, Melanie; Delius, Judith; Hofmann, Thomas; Hannig, Matthias

    2017-08-01

    This electron microscopic study aimed at investigating effects of oral astringent stimuli on the enamel pellicle's morphology. Pellicles were formed in situ within 30min on bovine enamel slabs, fixed to individuals' upper jaw splints. The pellicle-coated specimens were immersed in vitro in seven diverse astringent solutions and subsequently analyzed by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, as well as transmission electron microscopy (TEM). Four biocompatible astringents, namely the polyphenol epigallocatechin gallate, the metal salt iron(III) sulfate, the basic protein lysozyme, and the aminopolysaccharide chitosan, were additionally applied in situ. After rinsing the oral cavity with these compounds, the pellicle's ultrastructure was imaged by SEM and TEM, respectively. Untreated pellicle samples served as controls. Exposure to polyphenols and lysozyme induced particularly thicker and electron-denser pellicles in comparison to the control pellicle with similar characteristics in vitro and in situ. In contrast, acidic chitosan and metal salt solutions, respectively, revealed minor pellicle alterations. The incorporation of Fe and Al into the pellicles treated with the corresponding inorganic salts was verified by EDX analysis. Astringent-induced pellicle modifications were for the first time visualized by TEM. The ultrastructural alterations of the dental pellicle may partly explain the tooth-roughening effect caused by oral astringent stimuli. Astringents might modify the pellicle's protective properties against dental erosion, attrition, as well as bacterial adhesion, and by this means may influence tooth health. The findings may thus be particularly relevant for preventive dentistry. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Using Video as a Stimulus to Reveal Elementary Teachers' Mathematical Knowledge for Teaching

    Science.gov (United States)

    Barlow, Angela T.; Gaddy, Angeline K.; Baxter, Wesley A.

    2017-01-01

    The purpose of this article is to explore the usefulness of a video-based tool for measuring teachers' mathematical knowledge for teaching. Unique to this tool is the use of a video featuring a mathematical disagreement that occurred in an elementary classroom. The authors define mathematical disagreements as instances in which students challenge…

  3. Immunogold labeling of amelogenin in developing porcine enamel revealed by field emission scanning electron microscopy.

    Science.gov (United States)

    Du, Chang; Fan, Daming; Sun, Zhi; Fan, Yuwei; Lakshminarayanan, Rajamani; Moradian-Oldak, Janet

    2009-01-01

    The present study describes a method using immunohistochemical labeling in combination with high-resolution imaging (field emission scanning electron microscopy) to investigate the spatial localization of amelogenins on apatite crystallites in developing porcine enamel. Cross-sections of developing enamel tissue from freeze-fractured pig third molar were treated with antiserum against recombinant mouse amelogenin and immunoreactivity confirmed by Western blot analysis. The samples were then treated with the goat anti-rabbit IgG conjugated with 10-nm gold particles. The control samples were treated with the secondary antibody only. The in-lens secondary electrons detector and quadrant back-scattering detector were employed to reveal the high-resolution morphology of enamel structures and gold particle distribution. The immunolabeling showed a preference of the gold particle localization along the side faces of the ribbon-like apatite crystals. The preferential localization of amelogenin in vivo on enamel crystals strongly supports its direct function in controlling crystal morphology. Copyright 2008 S. Karger AG, Basel.

  4. Fluorescence Lifetime Imaging Microscopy reveals rerouting of SNARE trafficking driving dendritic cell activation

    Science.gov (United States)

    Verboogen, Daniëlle Rianne José; González Mancha, Natalia; ter Beest, Martin; van den Bogaart, Geert

    2017-01-01

    SNARE proteins play a crucial role in intracellular trafficking by catalyzing membrane fusion, but assigning SNAREs to specific intracellular transport routes is challenging with current techniques. We developed a novel Förster resonance energy transfer-fluorescence lifetime imaging microscopy (FRET-FLIM)-based technique allowing visualization of real-time local interactions of fluorescently tagged SNARE proteins in live cells. We used FRET-FLIM to delineate the trafficking steps underlying the release of the inflammatory cytokine interleukin-6 (IL-6) from human blood-derived dendritic cells. We found that activation of dendritic cells by bacterial lipopolysaccharide leads to increased FRET of fluorescently labeled syntaxin 4 with VAMP3 specifically at the plasma membrane, indicating increased SNARE complex formation, whereas FRET with other tested SNAREs was unaltered. Our results revealed that SNARE complexing is a key regulatory step for cytokine production by immune cells and prove the applicability of FRET-FLIM for visualizing SNARE complexes in live cells with subcellular spatial resolution. DOI: http://dx.doi.org/10.7554/eLife.23525.001 PMID:28524818

  5. In Vivo Microscopy Reveals Extensive Embedding of Capillaries within the Sarcolemma of Skeletal Muscle Fibers

    Science.gov (United States)

    Glancy, Brian; Hsu, Li-Yueh; Dao, Lam; Bakalar, Matthew; French, Stephanie; Chess, David J.; Taylor, Joni L.; Picard, Martin; Aponte, Angel; Daniels, Mathew P.; Esfahani, Shervin; Cushman, Samuel; Balaban, Robert S.

    2013-01-01

    Objective To provide insight into mitochondrial function in vivo, we evaluated the 3D spatial relationship between capillaries, mitochondria, and muscle fibers in live mice. Methods 3D volumes of in vivo murine Tibialis anterior muscles were imaged by multi-photon microscopy (MPM). Muscle fiber type, mitochondrial distribution, number of capillaries, and capillary-to-fiber contact were assessed. The role of myoglobin-facilitated diffusion was examined in myoglobin knockout mice. Distribution of GLUT4 was also evaluated in the context of the capillary and mitochondrial network. Results MPM revealed that 43.6 ± 3.3% of oxidative fiber capillaries had ≥ 50% of their circumference embedded in a groove in the sarcolemma, in vivo. Embedded capillaries were tightly associated with dense mitochondrial populations lateral to capillary grooves and nearly absent below the groove. Mitochondrial distribution, number of embedded capillaries, and capillary-to-fiber contact were proportional to fiber oxidative capacity and unaffected by myoglobin knockout. GLUT4 did not preferentially localize to embedded capillaries. Conclusions Embedding capillaries in the sarcolemma may provide a regulatory mechanism to optimize delivery of oxygen to heterogeneous groups of muscle fibers. We hypothesize that mitochondria locate to paravascular regions due to myofibril voids created by embedded capillaries, not to enhance the delivery of oxygen to the mitochondria. PMID:25279425

  6. Microscopy ambient ionization top-down mass spectrometry reveals developmental patterning.

    Science.gov (United States)

    Hsu, Cheng-Chih; White, Nicholas M; Hayashi, Marito; Lin, Eugene C; Poon, Tiffany; Banerjee, Indroneal; Chen, Ju; Pfaff, Samuel L; Macagno, Eduardo R; Dorrestein, Pieter C

    2013-09-10

    There is immense cellular and molecular heterogeneity in biological systems. Here, we demonstrate the utility of integrating an inverted light microscope with an ambient ionization source, nanospray electrospray desorption ionization, attached to a high-resolution mass spectrometer to characterize the molecular composition of mouse spinal cords. We detected a broad range of molecules, including peptides and proteins, as well as metabolites such as lipids, sugars, and other small molecules, including S-adenosyl methionine and glutathione, through top-down MS. Top-down analysis revealed variation in the expression of Hb, including the transition from fetal to adult Hb and heterogeneity in Hb subunits consistent with the genetic diversity of the mouse models. Similarly, temporal changes to actin-sequestering proteins β-thymosins during development were observed. These results demonstrate that interfacing microscopy with ambient ionization provides the means to perform targeted in situ ambient top-down mass spectral analysis to study the pattern of proteins, lipids, and sugars in biologically heterogeneous samples.

  7. Unidirectional growth of heavy meromyosin clusters along actin filaments revealed by real-time fluorescence microscopy.

    Science.gov (United States)

    Hirakawa, Rika; Nishikawa, Yusuke; Uyeda, Taro Q P; Tokuraku, Kiyotaka

    2017-12-01

    Heavy meromyosin (HMM) forms clusters along actin filaments under low ATP concentrations. Here, we observed the growth of HMM clusters under low concentrations of ATP in real time using fluorescence microscopy. When actin filaments were loosely immobilized on positively charged lipid bilayers, clusters of HMM-GFP were readily formed. Time-lapse observation revealed that the clusters grew unidirectionally. When we used a mixture of actin filaments and copolymers of actin and acto-S1dC, a chimeric protein of actin and the myosin motor domain, HMM-GFP preferentially formed clusters along the copolymers. We thus suggest that binding of myosin motors carrying ADP and Pi induces unidirectional conformational changes in actin filaments and allosterically recruits more myosin binding. In contrast, when actin filaments and copolymers were anchored to glass substrate via stable biotin-avidin linkage, higher concentrations of HMM-GFP were required to form clusters than on the lipid bilayer. Moreover, actin filaments and copolymers were not discriminated regarding preferential cluster formation. This is presumably because the myosin-induced cooperative conformational changes in actin filaments involve changes in the helical twist. Consistent with this, cofilin clusters, which supertwist the helix, were readily formed along loosely immobilized actin filaments, but not along those anchored via biotin-avidin linkage. © 2017 Wiley Periodicals, Inc.

  8. Surface topological differences of phage infected uropathogenic Escherichia coli (UPEC) strains, revealed by atomic force microscopy.

    Science.gov (United States)

    Hanif, Bassamah; Jamil, Nusrat; Shah, Muhammad Raza

    2016-01-01

    Atomic force microscopy (AFM) is an advance microscopic technique that provides three dimensional structures of cell surfaces with high resolution. In the present study AFM was used for comparative analysis of surface topology of phage infected and uninfected Uropathogenic Escherichia coli (UPEC) cells. Two UPEC strains NE and HN were isolated from urine samples of Urinary tract infection patients and their specific narrow host range lytic phages 3S and HNΦ were isolated from the sewage of different areas. On the basis of one step growth curve both phages characterized as short latent period phages with latency period of about 30 min. On AFM analysis significant difference in topology of healthy and infected cells were observed. It was hypothesized that progeny of both lytic phages released out from their respective host cells in different manner. The image of 3S infected UPEC host cells (NE) revealed multiple internal projections which showed progeny phages released out from host cells through these multiple sites. Whereas images of HNΦ infected HN host cells showed central depression which illustrated that new phages released out through single exit point from the middle of cell. These results are significant to extend future studies on isolated phages as an effective tool for phage therapy.

  9. Single molecule atomic force microscopy of aerolysin pore complexes reveals unexpected star-shaped topography.

    Science.gov (United States)

    He, Jianfeng; Wang, Jiabin; Hu, Jun; Sun, Jielin; Czajkowsky, Daniel Mark; Shao, Zhifeng

    2016-04-01

    Aerolysin is the paradigmatic member of a large family of toxins that convert from a water-soluble monomer/dimer into a membrane-spanning oligomeric pore. While there is x-ray crystallographic data of its water-soluble conformation, the most recent structural model of the membrane-inserted pore is based primarily on data of water-soluble tetradecamers of mutant protein, together with computational modeling ultimately performed in vacuum. Here we examine this pore model with atomic force microscopy (AFM) of membrane-associated wild-type complexes and all-atom molecular dynamics (MD) simulations in water. In striking contrast to a disc-shaped cap region predicted by the present model, the AFM images reveal a star-shaped complex, with a central ring surrounded by seven radial projections. Further, the MD simulations suggest that the locations of the receptor-binding (D1) domains in the present model are not correct. However, a modified model in which the D1 domains, rather than localized at fixed positions, adopt a wide range of configurations through fluctuations of an intervening linker is compatible with existing data. Thus our work not only demonstrates the importance of directly resolving such complexes in their native environment but also points to a dynamic receptor binding region, which may be critical for toxin assembly on the cell surface. Copyright © 2015 John Wiley & Sons, Ltd.

  10. Atomic force microscopy of bacteria reveals the mechanobiology of pore forming peptide action.

    Science.gov (United States)

    Mularski, Anna; Wilksch, Jonathan J; Hanssen, Eric; Strugnell, Richard A; Separovic, Frances

    2016-06-01

    Time-resolved AFM images revealed that the antimicrobial peptide (AMP) caerin 1.1 caused localised defects in the cell walls of lysed Klebsiella pneumoniae cells, corroborating a pore-forming mechanism of action. The defects continued to grow during the AFM experiment, in corroboration with large holes that were visualised by scanning electron microscopy. Defects in cytoplasmic membranes were visualised by cryo-EM using the same peptide concentration as in the AFM experiments. At three times the minimum inhibitory concentration of caerin, 'pores' were apparent in the outer membrane. The capsule of K. pneumoniae AJ218 was unchanged by exposure to caerin, indicating that the ionic interaction of the positively charged peptide with the negatively charged capsular polysaccharide is not a critical component of AMP interaction with K. pneumoniae AJ218 cells. Further, the presence of a capsule confers no advantage to wild-type over capsule-deficient cells when exposed to the AMP caerin. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Diversity of extracellular vesicles in human ejaculates revealed by cryo-electron microscopy

    Directory of Open Access Journals (Sweden)

    Johanna L. Höög

    2015-11-01

    Full Text Available Human ejaculates contain extracellular vesicles (EVs, that to a large extent are considered to originate from the prostate gland, and are often denominated “prostasomes.” These EVs are important for human fertility, for example by promoting sperm motility and by inducing immune tolerance of the female immune system to the spermatozoa. So far, the EVs present in human ejaculate have not been studied in their native state, inside the seminal fluid without prior purification and isolation procedures. Using cryo-electron microscopy and tomography, we performed a comprehensive inventory of human ejaculate EVs. The sample was neither centrifuged, fixed, filtered or sectioned, nor were heavy metals added. Approximately 1,500 extracellular structures were imaged and categorized. The extracellular environment of human ejaculate was found to be diverse, with 5 major subcategories of EVs and 6 subcategories of extracellular membrane compartments, including lamellar bodies. Furthermore, 3 morphological features, including electron density, double membrane bilayers and coated surface, are described in all subcategories. This study reveals that the extracellular environment in human ejaculate is multifaceted. Several novel morphological EV subcategories are identified and clues to their cellular origin may be found in their morphology. This inventory is therefore important for developing future experimental approaches, and to interpret previously published data to understand the role of EVs for human male fertility.

  12. Diversity of extracellular vesicles in human ejaculates revealed by cryo-electron microscopy

    Science.gov (United States)

    Höög, Johanna L.; Lötvall, Jan

    2015-01-01

    Human ejaculates contain extracellular vesicles (EVs), that to a large extent are considered to originate from the prostate gland, and are often denominated “prostasomes.” These EVs are important for human fertility, for example by promoting sperm motility and by inducing immune tolerance of the female immune system to the spermatozoa. So far, the EVs present in human ejaculate have not been studied in their native state, inside the seminal fluid without prior purification and isolation procedures. Using cryo-electron microscopy and tomography, we performed a comprehensive inventory of human ejaculate EVs. The sample was neither centrifuged, fixed, filtered or sectioned, nor were heavy metals added. Approximately 1,500 extracellular structures were imaged and categorized. The extracellular environment of human ejaculate was found to be diverse, with 5 major subcategories of EVs and 6 subcategories of extracellular membrane compartments, including lamellar bodies. Furthermore, 3 morphological features, including electron density, double membrane bilayers and coated surface, are described in all subcategories. This study reveals that the extracellular environment in human ejaculate is multifaceted. Several novel morphological EV subcategories are identified and clues to their cellular origin may be found in their morphology. This inventory is therefore important for developing future experimental approaches, and to interpret previously published data to understand the role of EVs for human male fertility. PMID:26563734

  13. Vesicular trafficking of immune mediators in human eosinophils revealed by immunoelectron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Melo, Rossana C.N., E-mail: rossana.melo@ufjf.edu.br [Laboratory of Cellular Biology, Department of Biology, ICB, Federal University of Juiz de Fora, UFJF, Rua José Lourenço Kelmer, Juiz de Fora, MG 36036-900 (Brazil); Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, CLS 943, Boston, MA 02215 (United States); Weller, Peter F. [Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, CLS 943, Boston, MA 02215 (United States)

    2016-10-01

    Electron microscopy (EM)-based techniques are mostly responsible for our current view of cell morphology at the subcellular level and continue to play an essential role in biological research. In cells from the immune system, such as eosinophils, EM has helped to understand how cells package and release mediators involved in immune responses. Ultrastructural investigations of human eosinophils enabled visualization of secretory processes in detail and identification of a robust, vesicular trafficking essential for the secretion of immune mediators via a non-classical secretory pathway associated with secretory (specific) granules. This vesicular system is mainly organized as large tubular-vesicular carriers (Eosinophil Sombrero Vesicles – EoSVs) actively formed in response to cell activation and provides a sophisticated structural mechanism for delivery of granule-stored mediators. In this review, we highlight the application of EM techniques to recognize pools of immune mediators at vesicular compartments and to understand the complex secretory pathway within human eosinophils involved in inflammatory and allergic responses. - Highlights: • Application of EM to understand the complex secretory pathway in human eosinophils. • EM techniques reveal an active vesicular system associated with secretory granules. • Tubular vesicles are involved in the transport of granule-derived immune mediators.

  14. Unidirectional Living Growth of Self-Assembled Protein Nanofibrils Revealed by Super-resolution Microscopy

    NARCIS (Netherlands)

    Beun, Lennart H.; Albertazzi, Lorenzo; Zwaag, van der Daan; Vries, de Renko; Cohen Stuart, Martien A.

    2016-01-01

    Protein-based nanofibrils are emerging as a promising class of materials that provide unique properties for applications such as biomedical and food engineering. Here, we use atomic force microscopy and stochastic optical reconstruction microscopy imaging to elucidate the growth dynamics,

  15. Long-term video surveillance and automated analyses reveal arousal patterns in groups of hibernating bats

    Science.gov (United States)

    Hayman, David T.S.; Cryan, Paul; Fricker, Paul D.; Dannemiller, Nicholas G.

    2017-01-01

    Understanding natural behaviours is essential to determining how animals deal with new threats (e.g. emerging diseases). However, natural behaviours of animals with cryptic lifestyles, like hibernating bats, are often poorly characterized. White-nose syndrome (WNS) is an unprecedented disease threatening multiple species of hibernating bats, and pathogen-induced changes to host behaviour may contribute to mortality. To better understand the behaviours of hibernating bats and how they might relate to WNS, we developed new ways of studying hibernation across entire seasons.We used thermal-imaging video surveillance cameras to observe little brown bats (Myotis lucifugus) and Indiana bats (M. sodalis) in two caves over multiple winters. We developed new, sharable software to test for autocorrelation and periodicity of arousal signals in recorded video.We processed 740 days (17,760 hr) of video at a rate of >1,000 hr of video imagery in less than 1 hr using a desktop computer with sufficient resolution to detect increases in arousals during midwinter in both species and clear signals of daily arousal periodicity in infected M. sodalis.Our unexpected finding of periodic synchronous group arousals in hibernating bats demonstrate the potential for video methods and suggest some bats may have innate behavioural strategies for coping with WNS. Surveillance video and accessible analysis software make it now practical to investigate long-term behaviours of hibernating bats and other hard-to-study animals.

  16. Peri-operative imaging of cancer margins with reflectance confocal microscopy during Mohs micrographic surgery: feasibility of a video-mosaicing algorithm

    Science.gov (United States)

    Flores, Eileen; Yelamos, Oriol; Cordova, Miguel; Kose, Kivanc; Phillips, William; Rossi, Anthony; Nehal, Kishwer; Rajadhyaksha, Milind

    2017-02-01

    Reflectance confocal microscopy (RCM) imaging shows promise for guiding surgical treatment of skin cancers. Recent technological advancements such as the introduction of the handheld version of the reflectance confocal microscope, video acquisition and video-mosaicing have improved RCM as an emerging tool to evaluate cancer margins during routine surgical skin procedures such as Mohs micrographic surgery (MMS). Detection of residual non-melanoma skin cancer (NMSC) tumor during MMS is feasible, as demonstrated by the introduction of real-time perioperative imaging on patients in the surgical setting. Our study is currently testing the feasibility of a new mosaicing algorithm for perioperative RCM imaging of NMSC cancer margins on patients during MMS. We report progress toward imaging and image analysis on forty-five patients, who presented for MMS at the MSKCC Dermatology service. The first 10 patients were used as a training set to establish an RCM imaging algorithm, which was implemented on the remaining test set of 35 patients. RCM imaging, using 35% AlCl3 for nuclear contrast, was performed pre- and intra-operatively with the Vivascope 3000 (Caliber ID). Imaging was performed in quadrants in the wound, to simulate the Mohs surgeon's examination of pathology. Videos were taken at the epidermal and deep dermal margins. Our Mohs surgeons assessed all videos and video-mosaics for quality and correlation to histology. Overall, our RCM video-mosaicing algorithm is feasible. RCM videos and video-mosaics of the epidermal and dermal margins were found to be of clinically acceptable quality. Assessment of cancer margins was affected by type of NMSC, size and location. Among the test set of 35 patients, 83% showed acceptable imaging quality, resolution and contrast. Visualization of nuclear and cellular morphology of residual BCC/SCC tumor and normal skin features could be detected in the peripheral and deep dermal margins. We observed correlation between the RCM videos/video

  17. Modes of Escherichia coli Dps Interaction with DNA as Revealed by Atomic Force Microscopy.

    Directory of Open Access Journals (Sweden)

    Vladislav V Melekhov

    Full Text Available Multifunctional protein Dps plays an important role in iron assimilation and a crucial role in bacterial genome packaging. Its monomers form dodecameric spherical particles accumulating ~400 molecules of oxidized iron ions within the protein cavity and applying a flexible N-terminal ends of each subunit for interaction with DNA. Deposition of iron is a well-studied process by which cells remove toxic Fe2+ ions from the genetic material and store them in an easily accessible form. However, the mode of interaction with linear DNA remained mysterious and binary complexes with Dps have not been characterized so far. It is widely believed that Dps binds DNA without any sequence or structural preferences but several lines of evidence have demonstrated its ability to differentiate gene expression, which assumes certain specificity. Here we show that Dps has a different affinity for the two DNA fragments taken from the dps gene regulatory region. We found by atomic force microscopy that Dps predominantly occupies thermodynamically unstable ends of linear double-stranded DNA fragments and has high affinity to the central part of the branched DNA molecule self-assembled from three single-stranded oligonucleotides. It was proposed that Dps prefers binding to those regions in DNA that provide more contact pads for the triad of its DNA-binding bundle associated with one vertex of the protein globule. To our knowledge, this is the first study revealed the nucleoid protein with an affinity to branched DNA typical for genomic regions with direct and inverted repeats. As a ubiquitous feature of bacterial and eukaryotic genomes, such structural elements should be of particular care, but the protein system evolutionarily adapted for this function is not yet known, and we suggest Dps as a putative component of this system.

  18. Bimodal dynamics of granular organelles in primary renin-expressing cells revealed using TIRF microscopy.

    Science.gov (United States)

    Buckley, Charlotte; Dun, Alison R; Peter, Audrey; Bellamy, Christopher; Gross, Kenneth W; Duncan, Rory R; Mullins, John J

    2017-01-01

    Renin is the initiator and rate-limiting factor in the renin-angiotensin blood pressure regulation system. Although renin is not exclusively produced in the kidney, in nonmurine species the synthesis and secretion of the active circulatory enzyme is confined almost exclusively to the dense core granules of juxtaglomerular (JG) cells, where prorenin is processed and stored for release via a regulated pathway. Despite its importance, the structural organization and regulation of granules within these cells is not well understood, in part due to the difficulty in culturing primary JG cells in vitro and the lack of appropriate cell lines. We have streamlined the isolation and culture of primary renin-expressing cells suitable for high-speed, high-resolution live imaging using a Percoll gradient-based procedure to purify cells from RenGFP+ transgenic mice. Fibronectin-coated glass coverslips proved optimal for the adhesion of renin-expressing cells and facilitated live cell imaging at the plasma membrane of primary renin cells using total internal reflection fluorescence microscopy (TIRFM). To obtain quantitative data on intracellular function, we stained mixed granule and lysosome populations with Lysotracker Red and stimulated cells using 100 nM isoproterenol. Analysis of membrane-proximal acidic granular organelle dynamics and behavior within renin-expressing cells revealed the existence of two populations of granular organelles with distinct functional responses following isoproterenol stimulation. The application of high-resolution techniques for imaging JG and other specialized kidney cells provides new opportunities for investigating renal cell biology. Copyright © 2017 the American Physiological Society.

  19. Peculiarities of living cell response to the external stimuli revealed via quasistatic mode of atomic force microscopy

    Science.gov (United States)

    Khalisov, M. M.; Ankudinov, A. V.; Penniyaynen, V. A.; Timoshenko, T. E.; Timoshchuk, K. I.; Samsonov, M. V.; Shirinsky, V. P.

    2017-10-01

    The technique of atomic force microscopy allows revealing living cell morphology and mechanical properties characterization under physiologically relevant conditions. Here, we review our recent results on living cell reaction to different external influences obtained by this technique. The Bruker PeakForce QNM quasistatic mode was used to study living fibroblasts, erythrocytes, sensory neurons, and endothelial cells.

  20. Dynamics of cellular response to hypotonic stimulation revealed by quantitative phase microscopy and multi-fractal detrended fluctuation analysis

    Science.gov (United States)

    Cardenas, Nelson; Kumar, Satish; Mohanty, Samarendra

    2012-11-01

    Hypotonic stimulation is known to cause morphological changes in cells and also leads to modulation of cellular physiology. In order to evaluate the dynamics of cellular response to hypotonic stimulation, we utilized digital holographic microscopy for quantitative phase microscopy, achieved by a common-path interferometry geometry based on extraction of reference beam by spatial-filtering. Results from live cell investigations demonstrate the capability of this method for dynamic quantitative phase imaging. Further, wavelet and multi-fractal detrended fluctuation analysis revealed that the dynamic phase changes, in response to hypotonic stimulation, are multifractal in nature.

  1. Imaging of organelles by electron microscopy reveals protein-protein interactions in mitochondria and chloroplasts

    NARCIS (Netherlands)

    Dudkina, Natalya V.; Kouril, Roman; Bultema, Jelle B.; Boekema, Egbert J.

    2010-01-01

    Ongoing progress in electron microscopy (EM) offers now an opening to visualize cells at the nanoscale by cryo-electron tomography (ET). Large protein complexes can be resolved at near-atomic resolution by single particle averaging. Some examples from mitochondria and chloroplasts illustrate the

  2. Revealing the dark side of Portlandite Clusters in cement paste by circular polarization microscopy

    NARCIS (Netherlands)

    Copuroglu, O.

    2016-01-01

    Plane and crossed polarization are the two standard light modes in polarized light microscopy that are widely used to characterize crystalline and amorphous phases in cement-based materials. However, the use of the crossed polarized light mode has been found to be restrictive for studying

  3. A general mechanism of ribosome dimerization revealed by single-particle cryo-electron microscopy

    NARCIS (Netherlands)

    Franken, Linda; Oostergetel, Gerrit; Pijning, Tjaard; Puri, Pranav; Arkhipova, Valentina Ivanovna; Boekema, Egbert; Poolman, Berend; Guskov, Albert

    2017-01-01

    Bacteria downregulate their ribosomal activity through dimerization of 70S ribosomes, yielding inactive 100S complexes. In Escherichia coli, dimerization is mediated by the hibernation promotion factor (HPF) and ribosome modulation factor. Here we report the cryo-electron microscopy study on 100S

  4. Ovipositor setation in oldest insects (Insecta: Archaeognatha) revealed by SEM and He-ion microscopy.

    Science.gov (United States)

    Matushkina, Nataliia A

    2017-10-01

    Archaeognatha represent the oldest living lineage of true insects (=Ectognatha), which are remarkable, among others, for plesiomorphic genital morphology and complicated mating behaviour. I used scanning electron microscopy and He-ion microscopy to examine the ovipositor morphology of seven species, in order to describe the cuticle microsculpture. The species studied are characterised by different types of the ovipositor setation pattern, which are considered an important taxonomic feature for Archaeognatha. The common and well discernible elements of ovipositor setation in Archaeognatha are: (1) non-articulated terminal seta, (2) grooved type I basiconic sensillum with apical pore, (3) multiporous type II basiconic sensillum, (4) articulated setae of different length. Coeloconica-like sensilla and campaniform sensilla demonstrate a variety of transient morphology. Results of this study provide morphological evidence of presence of olfactory receptors on the ovipositor in Archaeognatha. The possible functions of the ovipositor setation in Archaeognatha are discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Changes in optical properties of electroporated cells as revealed by digital holographic microscopy

    OpenAIRE

    Calin, Violeta L.; Mihailescu, Mona; Mihale, Nicolae; Baluta, Alexandra V.; Kovacs, Eugenia; Savopol, Tudor; Moisescu, Mihaela G.

    2017-01-01

    Changes in optical and shape-related characteristics of B16F10 cells after electroporation were investigated using digital holographic microscopy (DHM). Bipolar rectangular pulses specific for electrochemotherapy were used. Electroporation was performed in an ?off-axis? DHM set-up without using exogenous markers. Two types of cell parameters were monitored seconds and minutes after pulse train application: parameters addressing a specifically defined area of the cell (refractive index and cel...

  6. Resonant second-harmonic-generation circular-dichroism microscopy reveals molecular chirality in native biological tissues

    CERN Document Server

    Chen, Mei-Yu; Kan, Che-Wei; Lin, Yen-Yin; Ye, Cin-Wei; Wu, Meng-Jer; Liu, Hsiang-Lin; Chu, Shi-Wei

    2016-01-01

    Conventional linear optical activity effects are widely used for studying chiral materials. However, poor contrast and artifacts due to sample anisotropy limit the applicability of these methods. Here we demonstrate that nonlinear second-harmonic-generation circular dichroism spectral microscopy can overcome these limits. In intact collagenous tissues, clear spectral resonance is observed with sub-micrometer spatial resolution. By performing gradual protein denaturation studies, we show that the resonant responses are dominantly due to the molecular chirality.

  7. Features of Blastocystis spp. in xenic culture revealed by deconvolutional microscopy

    OpenAIRE

    Nagel, Robyn; Gray, Christian; Bielefeldt-Ohmann, Helle; Traub, Rebecca J.

    2015-01-01

    Blastocystis spp. are common human enteric parasites with complex morphology and have been reported to cause irritable bowel syndrome (IBS). Deconvolutional microscopy with time-lapse imaging and fluorescent spectroscopy of xenic cultures of Blastocystis spp. from stool samples of IBS patients and from asymptomatic, healthy pigs allowed observations of living organisms in their natural microbial environment. Blastocystis organisms of the vacuolated, granular, amoebic and cystic forms were obs...

  8. Combined Use of Electron and Light Microscopy Techniques Reveals False Secondary Shell Units in Megaloolithidae Eggshells.

    Science.gov (United States)

    Moreno-Azanza, Miguel; Bauluz, Blanca; Canudo, José Ignacio; Gasca, José Manuel; Torcida Fernández-Baldor, Fidel

    2016-01-01

    Abnormalities in the histo- and ultrastructure of the amniote eggshell are often related to diverse factors, such as ambient stress during egg formation, pathologies altering the physiology of the egg-laying females, or evolutionarily selected modifications of the eggshell structure that vary the physical properties of the egg, for example increasing its strength so as to avoid fracture during incubation. When dealing with fossil materials, all the above hypotheses are plausible, but a detailed taphonomical study has to be performed to rule out the possibility that secondary processes of recrystallization have occurred during fossilization. Traditional analyses, such as optical microscopy inspection and cathodoluminescence, have proven not to be enough to understand the taphonomic story of some eggshells. Recently, electron backscatter diffraction has been used, in combination with other techniques, to better understand the alteration of fossil eggshells. Here we present a combined study using scanning electron microscopy, optical microscopy, cathodoluminescence and electron backscatter diffraction of eggshell fragments assigned to Megaloolithus cf. siruguei from the Upper Cretaceous outcrops of the Cameros Basin. We focus our study on the presence of secondary shell units that mimic most aspects of the ultrastructure of the eggshell mammillae, but grow far from the inner surface of the eggshell. We call these structures extra-spherulites, describe their crystal structure and demonstrate their secondary origin. Our study has important implications for the interpretation of secondary shell units as biological or pathological structures. Thus, electron backscatter diffraction complements other microscope techniques as a useful tool for understanding taphonomical alterations in fossil eggshells.

  9. Immunogold scanning electron microscopy can reveal the polysaccharide architecture of xylem cell walls.

    Science.gov (United States)

    Sun, Qiang; Sun, Yuliang; Juzenas, Kevin

    2017-04-01

    Immunofluorescence microscopy (IFM) and immunogold transmission electron microscopy (TEM) are the two main techniques commonly used to detect polysaccharides in plant cell walls. Both are important in localizing cell wall polysaccharides, but both have major limitations, such as low resolution in IFM and restricted sample size for immunogold TEM. In this study, we have developed a robust technique that combines immunocytochemistry with scanning electron microscopy (SEM) to study cell wall polysaccharide architecture in xylem cells at high resolution over large areas of sample. Using multiple cell wall monoclonal antibodies (mAbs), this immunogold SEM technique reliably localized groups of hemicellulosic and pectic polysaccharides in the cell walls of five different xylem structures (vessel elements, fibers, axial and ray parenchyma cells, and tyloses). This demonstrates its important advantages over the other two methods for studying cell wall polysaccharide composition and distribution in these structures. In addition, it can show the three-dimensional distribution of a polysaccharide group in the vessel lateral wall and the polysaccharide components in the cell wall of developing tyloses. This technique, therefore, should be valuable for understanding the cell wall polysaccharide composition, architecture and functions of diverse cell types. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  10. Scanning a microhabitat: plant-microbe interactions revealed by confocal laser microscopy.

    Science.gov (United States)

    Cardinale, Massimiliano

    2014-01-01

    No plant or cryptogam exists in nature without microorganisms associated with its tissues. Plants as microbial hosts are puzzles of different microhabitats, each of them colonized by specifically adapted microbiomes. The interactions with such microorganisms have drastic effects on the host fitness. Since the last 20 years, the combination of microscopic tools and molecular approaches contributed to new insights into microbe-host interactions. Particularly, confocal laser scanning microscopy (CLSM) facilitated the exploration of microbial habitats and allowed the observation of host-associated microorganisms in situ with an unprecedented accuracy. Here I present an overview of the progresses made in the study of the interactions between microorganisms and plants or plant-like organisms, focusing on the role of CLSM for the understanding of their significance. I critically discuss risks of misinterpretation when procedures of CLSM are not properly optimized. I also review approaches for quantitative and statistical analyses of CLSM images, the combination with other molecular and microscopic methods, and suggest the re-evaluation of natural autofluorescence. In this review, technical aspects were coupled with scientific outcomes, to facilitate the readers in identifying possible CLSM applications in their research or to expand their existing potential. The scope of this review is to highlight the importance of confocal microscopy in the study of plant-microbe interactions and also to be an inspiration for integrating microscopy with molecular techniques in future researches of microbial ecology.

  11. Scanning a microhabitat: plant-microbe interactions revealed by confocal laser microscopy

    Directory of Open Access Journals (Sweden)

    Massimiliano eCardinale

    2014-03-01

    Full Text Available No plant or cryptogam exists in nature without microorganisms associated with its tissues. Plants as microbial hosts are puzzles of different microhabitats, each of them colonized by specifically adapted microbiomes. The interactions with such microorganisms have drastic effects on the host fitness. Since the last 20 years, the combination of microscopic tools and molecular approaches contributed to new insights into microbe-host interactions. Particularly, confocal laser scanning microscopy (CLSM facilitated the exploration of microbial habitats and allowed the observation of host-associated microorganisms in situ with an unprecedented accuracy. Here I present an overview of the progresses made in the study of the interactions between microorganisms and plants or plant-like organisms, focusing on the role of CLSM for the understanding of their significance. I critically discuss risks of misinterpretation when procedures of CLSM are not properly optimized. I also review approaches for quantitative and statistical analyses of CLSM images, the combination with other molecular and microscopic methods, and suggest the re-evaluation of natural autofluorescence. In this review, technical aspects were coupled with scientific outcomes, to facilitate the readers in identifying possible CLSM applications in their research or to expand their existing potential. The scope of this review is to highlight the importance of confocal microscopy in the study of plant-microbe interactions and also to be an inspiration for integrating microscopy with molecular techniques in future researches of microbial ecology.

  12. Combined Use of Electron and Light Microscopy Techniques Reveals False Secondary Shell Units in Megaloolithidae Eggshells.

    Directory of Open Access Journals (Sweden)

    Miguel Moreno-Azanza

    Full Text Available Abnormalities in the histo- and ultrastructure of the amniote eggshell are often related to diverse factors, such as ambient stress during egg formation, pathologies altering the physiology of the egg-laying females, or evolutionarily selected modifications of the eggshell structure that vary the physical properties of the egg, for example increasing its strength so as to avoid fracture during incubation. When dealing with fossil materials, all the above hypotheses are plausible, but a detailed taphonomical study has to be performed to rule out the possibility that secondary processes of recrystallization have occurred during fossilization. Traditional analyses, such as optical microscopy inspection and cathodoluminescence, have proven not to be enough to understand the taphonomic story of some eggshells. Recently, electron backscatter diffraction has been used, in combination with other techniques, to better understand the alteration of fossil eggshells. Here we present a combined study using scanning electron microscopy, optical microscopy, cathodoluminescence and electron backscatter diffraction of eggshell fragments assigned to Megaloolithus cf. siruguei from the Upper Cretaceous outcrops of the Cameros Basin. We focus our study on the presence of secondary shell units that mimic most aspects of the ultrastructure of the eggshell mammillae, but grow far from the inner surface of the eggshell. We call these structures extra-spherulites, describe their crystal structure and demonstrate their secondary origin. Our study has important implications for the interpretation of secondary shell units as biological or pathological structures. Thus, electron backscatter diffraction complements other microscope techniques as a useful tool for understanding taphonomical alterations in fossil eggshells.

  13. Quantitative microscopy reveals 3D organization and kinetics of endocytosis in rat hepatocytes.

    Science.gov (United States)

    Marbet, Permsin; Rahner, Christoph; Stieger, Bruno; Landmann, Lukas

    2006-09-01

    In order to demonstrate the power of quantitative microscopy, the endocytic apparatus of rat hepatocytes was reexamined using in situ liver and short term cultured hepatocyte couplets that were allowed to internalize endocytic markers for various time intervals. Correlative confocal light and electron microscopy demonstrate a tubulovesicular reticulum representing the endocytic apparatus. Volume and membrane area account for 2% of cell volume and 30% plasma membrane surface. Colocalization analysis demonstrated that pathway-specific ligands and fluid-phase markers enter EEA1-positive vesicles, the early endosomal compartment, immediately after internalization. These vesicles are translocated rapidly from basolateral to perinuclear and apical locations. Ligands are sorted within 5 min to their respective pathways. Sequential colocalization of an asialoglycoprotein-pulse with rab7 and lamp3 demonstrates that early endosomes change into or fuse with late endosomes and lysosomes. Alternatively, markers are sequestered into the common endosome consisting of rab11-positive, long tubules that originate from early endosomes and show an affinity for the transcytotic marker pIgA and its receptor. This compartment mediates transcytosis by delivering the receptor-ligand complex to the subapical compartment, a set of apical, rab11-positive vesicles, which are connected to the tubular reticulum. We conclude that vesicular traffic between preexisting compartments, maturation or fusion of endocytic organelles, and transport in tubules act in concert and together mediate transport between compartments of a tubulovesicular endocytic apparatus. In addition, we show that quantitative microscopy using high resolution data sets can detect and characterize kinetics of various parameters thus adding a dynamic component to 3D information. (c) 2006 Wiley-Liss, Inc.

  14. Super-resolution microscopy reveals protein spatial reorganization in early innate immune responses.

    Energy Technology Data Exchange (ETDEWEB)

    Carson, Bryan D.; Aaron, Jesse S.; Timlin, Jerilyn Ann

    2010-10-01

    Over the past decade optical approaches were introduced that effectively break the diffraction barrier. Of particular note were introductions of Stimulated Emission/Depletion (STED) microscopy, Photo-Activated Localization Microscopy (PALM), and the closely related Stochastic Optical Reconstruction Microscopy (STORM). STORM represents an attractive method for researchers, as it does not require highly specialized optical setups, can be implemented using commercially available dyes, and is more easily amenable to multicolor imaging. We implemented a simultaneous dual-color, direct-STORM imaging system through the use of an objective-based TIRF microscope and filter-based image splitter. This system allows for excitation and detection of two fluorophors simultaneously, via projection of each fluorophor's signal onto separate regions of a detector. We imaged the sub-resolution organization of the TLR4 receptor, a key mediator of innate immune response, after challenge with lipopolysaccharide (LPS), a bacteria-specific antigen. While distinct forms of LPS have evolved among various bacteria, only some LPS variations (such as that derived from E. coli) typically result in significant cellular immune response. Others (such as from the plague bacteria Y. pestis) do not, despite affinity to TLR4. We will show that challenge with LPS antigens produces a statistically significant increase in TLR4 receptor clusters on the cell membrane, presumably due to recruitment of receptors to lipid rafts. These changes, however, are only detectable below the diffraction limit and are not evident using conventional imaging methods. Furthermore, we will compare the spatiotemporal behavior of TLR4 receptors in response to different LPS chemotypes in order to elucidate possible routes by which pathogens such as Y. pestis are able to circumvent the innate immune system. Finally, we will exploit the dual-color STORM capabilities to simultaneously image LPS and TLR4 receptors in the

  15. Recruitment, assembly, and molecular architecture of the SpoIIIE DNA pump revealed by superresolution microscopy.

    Directory of Open Access Journals (Sweden)

    Jean-Bernard Fiche

    Full Text Available ATP-fuelled molecular motors are responsible for rapid and specific transfer of double-stranded DNA during several fundamental processes, such as cell division, sporulation, bacterial conjugation, and viral DNA transport. A dramatic example of intercompartmental DNA transfer occurs during sporulation in Bacillus subtilis, in which two-thirds of a chromosome is transported across a division septum by the SpoIIIE ATPase. Here, we use photo-activated localization microscopy, structured illumination microscopy, and fluorescence fluctuation microscopy to investigate the mechanism of recruitment and assembly of the SpoIIIE pump and the molecular architecture of the DNA translocation complex. We find that SpoIIIE assembles into ∼45 nm complexes that are recruited to nascent sites of septation, and are subsequently escorted by the constriction machinery to the center of sporulation and division septa. SpoIIIE complexes contain 47±20 SpoIIIE molecules, a majority of which are assembled into hexamers. Finally, we show that directional DNA translocation leads to the establishment of a compartment-specific, asymmetric complex that exports DNA. Our data are inconsistent with the notion that SpoIIIE forms paired DNA conducting channels across fused membranes. Rather, our results support a model in which DNA translocation occurs through an aqueous DNA-conducting pore that could be structurally maintained by the divisional machinery, with SpoIIIE acting as a checkpoint preventing membrane fusion until completion of chromosome segregation. Our findings and proposed mechanism, and our unique combination of innovating methodologies, are relevant to the understanding of bacterial cell division, and may illuminate the mechanisms of other complex machineries involved in DNA conjugation and protein transport across membranes.

  16. Changes in optical properties of electroporated cells as revealed by digital holographic microscopy.

    Science.gov (United States)

    Calin, Violeta L; Mihailescu, Mona; Mihale, Nicolae; Baluta, Alexandra V; Kovacs, Eugenia; Savopol, Tudor; Moisescu, Mihaela G

    2017-04-01

    Changes in optical and shape-related characteristics of B16F10 cells after electroporation were investigated using digital holographic microscopy (DHM). Bipolar rectangular pulses specific for electrochemotherapy were used. Electroporation was performed in an "off-axis" DHM set-up without using exogenous markers. Two types of cell parameters were monitored seconds and minutes after pulse train application: parameters addressing a specifically defined area of the cell (refractive index and cell height) and global cell parameters (projected area, optical phase shift profile and dry mass). The biphasic behavior of cellular parameters was explained by water and mannitol dynamics through the electropermeabilized cell membrane.

  17. Changes in optical properties of electroporated cells as revealed by digital holographic microscopy

    Science.gov (United States)

    Calin, Violeta L.; Mihailescu, Mona; Mihale, Nicolae; Baluta, Alexandra V.; Kovacs, Eugenia; Savopol, Tudor; Moisescu, Mihaela G.

    2017-01-01

    Changes in optical and shape-related characteristics of B16F10 cells after electroporation were investigated using digital holographic microscopy (DHM). Bipolar rectangular pulses specific for electrochemotherapy were used. Electroporation was performed in an “off-axis” DHM set-up without using exogenous markers. Two types of cell parameters were monitored seconds and minutes after pulse train application: parameters addressing a specifically defined area of the cell (refractive index and cell height) and global cell parameters (projected area, optical phase shift profile and dry mass). The biphasic behavior of cellular parameters was explained by water and mannitol dynamics through the electropermeabilized cell membrane. PMID:28736667

  18. Revealing the Formation of Copper Nanoparticles from a Homogeneous Solid Precursor by Electron Microscopy

    DEFF Research Database (Denmark)

    van den Berg, Roy; Elkjær, Christian Fink; Gommes, Cedric J.

    2016-01-01

    -and-growth scenario involving autocatalytic reduction of the copper phyllosilicate followed by diffusion-limited or reaction-limited growth of the copper nanoparticles. The plate-like structure of the precursor restricted the diffusion of copper and the autocatalytic reduction limited the probability for secondary...... nucleation. The combination of a uniform size of precursor particles and the autocatalytic reduction thus offers means to synthesize nanoparticles with well-defined sizes in large amounts. In this way, in situ observations made by electron microscopy provide mechanistic and kinetic insights...

  19. Atomic-scale structure of dislocations revealed by scanning tunneling microscopy and molecular dynamics

    DEFF Research Database (Denmark)

    Christiansen, Jesper; Morgenstern, K.; Schiøtz, Jakob

    2002-01-01

    The intersection between dislocations and a Ag(111) surface has been studied using an interplay of scanning tunneling microscopy (STM) and molecular dynamics. Whereas the STM provides atomically resolved information about the surface structure and Burgers vectors of the dislocations......, the simulations can be used to determine dislocation structure and orientation in the near-surface region. In a similar way, the subsurface structure of other extended defects can be studied. The simulations show dislocations to reorient the partials in the surface region leading to an increased splitting width...

  20. Single molecule tracking fluorescence microscopy in mitochondria reveals highly dynamic but confined movement of Tom40.

    Science.gov (United States)

    Kuzmenko, Anton; Tankov, Stoyan; English, Brian P; Tarassov, Ivan; Tenson, Tanel; Kamenski, Piotr; Elf, Johan; Hauryliuk, Vasili

    2011-01-01

    Tom40 is an integral protein of the mitochondrial outer membrane, which as the central component of the Translocase of the Outer Membrane (TOM) complex forms a channel for protein import. We characterize the diffusion properties of individual Tom40 molecules fused to the photoconvertable fluorescent protein Dendra2 with millisecond temporal resolution. By imaging individual Tom40 molecules in intact isolated yeast mitochondria using photoactivated localization microscopy with sub-diffraction limited spatial precision, we demonstrate that Tom40 movement in the outer mitochondrial membrane is highly dynamic but confined in nature, suggesting anchoring of the TOM complex as a whole.

  1. Structural and functional alterations of cellular components as revealed by electron microscopy.

    Science.gov (United States)

    Condello, Maria; Caraglia, Michele; Castellano, Maria; Arancia, Giuseppe; Meschini, Stefania

    2013-10-01

    Scanning (SEM) and transmission electron microscopy (TEM) are two fundamental microscopic techniques widely applied in biological research for the study of ultrastructural cell components. With these methods, especially TEM, it is possible to detect and quantify the morphological and ultrastructural parameters of intracellular organelles (mitochondria, Golgi apparatus, lysosomes, peroxisomes, endosomes, endoplasmic reticulum, cytoskeleton, nucleus, etc.) in normal and pathological conditions. The study of intracellular vesicle compartmentalization is raising even more interest in the light of the importance of intracellular localization of mediators of the signaling in eliciting different biological responses. The study of the morphology of some intracellular organelles can supply information on the bio-energetic status of the cells. TEM has also a pivotal role in the determination of different types of programmed cell death. In fact, the visualization of autophagosomes and autophagolysosomes is essential to determine the occurrence of autophagy (and also to discriminate micro-autophagy from macro-autophagy), while the presence of fragmented nuclei and surface blebbing is characteristic of apoptosis. SEM is particularly useful for the study of the morphological features of the cells and, therefore, can shed light, for instance, on cell-cell interactions. After a brief introduction on the basic principles of the main electron microscopy methods, the article describes some cell components with the aim to demonstrate the huge role of the ultrastructural analysis played in the knowledge of the relationship between function and structure of the biological objects. Copyright © 2013 Wiley Periodicals, Inc.

  2. Versatility of the green microalga cell vacuole function as revealed by analytical transmission electron microscopy.

    Science.gov (United States)

    Shebanova, Anastasia; Ismagulova, Tatiana; Solovchenko, Alexei; Baulina, Olga; Lobakova, Elena; Ivanova, Alexandra; Moiseenko, Andrey; Shaitan, Konstantin; Polshakov, Vladimir; Nedbal, Ladislav; Gorelova, Olga

    2017-05-01

    Vacuole is a multifunctional compartment central to a large number of functions (storage, catabolism, maintenance of the cell homeostasis) in oxygenic phototrophs including microalgae. Still, microalgal cell vacuole is much less studied than that of higher plants although knowledge of the vacuolar structure and function is essential for understanding physiology of nutrition and stress tolerance of microalgae. Here, we combined the advanced analytical and conventional transmission electron microscopy methods to obtain semi-quantitative, spatially resolved at the subcellular level information on elemental composition of the cell vacuoles in several free-living and symbiotic chlorophytes. We obtained a detailed record of the changes in cell and vacuolar ultrastructure in response to environmental stimuli under diverse conditions. We suggested that the vacuolar inclusions could be divided into responsible for storage of phosphorus (mainly in form of polyphosphate) and those accommodating non-protein nitrogen (presumably polyamine) reserves, respectively.The ultrastructural findings, together with the data on elemental composition of different cell compartments, allowed us to speculate on the role of the vacuolar membrane in the biosynthesis and sequestration of polyphosphate. We also describe the ultrastructural evidence of possible involvement of the tonoplast in the membrane lipid turnover and exchange of energy and metabolites between chloroplasts and mitochondria. These processes might play a significant role in acclimation in different stresses including nitrogen starvation and extremely high level of CO2 and might also be of importance for microalgal biotechnology. Advantages and limitations of application of analytical electron microscopy to biosamples such as microalgal cells are discussed.

  3. HDL surface lipids mediate CETP binding as revealed by electron microscopy and molecular dynamics simulation

    Science.gov (United States)

    Zhang, Meng; Charles, River; Tong, Huimin; Zhang, Lei; Patel, Mili; Wang, Francis; Rames, Matthew J.; Ren, Amy; Rye, Kerry-Anne; Qiu, Xiayang; Johns, Douglas G.; Charles, M. Arthur; Ren, Gang

    2015-03-01

    Cholesteryl ester transfer protein (CETP) mediates the transfer of cholesterol esters (CE) from atheroprotective high-density lipoproteins (HDL) to atherogenic low-density lipoproteins (LDL). CETP inhibition has been regarded as a promising strategy for increasing HDL levels and subsequently reducing the risk of cardiovascular diseases (CVD). Although the crystal structure of CETP is known, little is known regarding how CETP binds to HDL. Here, we investigated how various HDL-like particles interact with CETP by electron microscopy and molecular dynamics simulations. Results showed that CETP binds to HDL via hydrophobic interactions rather than protein-protein interactions. The HDL surface lipid curvature generates a hydrophobic environment, leading to CETP hydrophobic distal end interaction. This interaction is independent of other HDL components, such as apolipoproteins, cholesteryl esters and triglycerides. Thus, disrupting these hydrophobic interactions could be a new therapeutic strategy for attenuating the interaction of CETP with HDL.

  4. Germinal Center Dynamics Revealed by Multiphoton Microscopy Using a Photoactivatable Fluorescent Reporter

    Science.gov (United States)

    Victora, Gabriel D.; Schwickert, Tanja A.; Fooksman, David R.; Kamphorst, Alice O.; Meyer-Hermann, Michael; Dustin, Michael L.; Nussenzweig, Michel C.

    2010-01-01

    SUMMARY The germinal center (GC) reaction produces high-affinity antibodies by random mutation and selective clonal expansion of B cells with high-affinity receptors. However, the mechanism by which B cells are selected remains unclear, as does the role of the two anatomically-defined areas of the GC, light zone (LZ) and dark zone (DZ). We combined a new transgenic photoactivatable green fluorescent protein (PA-GFP) tracer with multiphoton laser-scanning microscopy and flow cytometry to examine anatomically defined LZ and DZ B cells and GC selection. We find that B cell division is restricted to the DZ, and that there is a net vector of B cell movement from the DZ to the LZ. The decision to return from the LZ to the DZ and undergo clonal expansion is controlled by T cells, which discern between LZ B cells based on the amount of antigen captured, providing a mechanism for GC selection. PMID:21074050

  5. Nonlinear bio-photonic crystal effects revealed with multimodal nonlinear microscopy.

    Science.gov (United States)

    Chu, S-W; Chen, I-H; Liu, T-M; Sun, C-K; Lee, S-P; Lin, B-L; Cheng, P-C; Kuo, M-X; Lin, D-J; Liu, H-L

    2002-12-01

    Highly optically active nonlinear bio-photonic crystalline and semicrystalline structures in living cells were studied by a novel multimodal nonlinear microscopy. Numerous biological structures, including stacked membranes and aligned protein structures are highly organized on a nanoscale and have been found to exhibit strong optical activities through second-harmonic generation (SHG) interactions, behaving similarly to man-made nonlinear photonic crystals. The microscopic technology used in this study is based on a combination of different imaging modes including SHG, third-harmonic generation, and multiphoton-induced fluorescence. With no energy release during harmonic generation processes, the nonlinear-photonic-crystal-like SHG activity is useful for investigating the dynamics of structure-function relationships at subcellular levels and is ideal for studying living cells, as minimal or no preparation is required.

  6. Topography of Cells Revealed by Variable-Angle Total Internal Reflection Fluorescence Microscopy.

    Science.gov (United States)

    Cardoso Dos Santos, Marcelina; Déturche, Régis; Vézy, Cyrille; Jaffiol, Rodolphe

    2016-09-20

    We propose an improved version of variable-angle total internal reflection fluorescence microscopy (vaTIRFM) adapted to modern TIRF setup. This technique involves the recording of a stack of TIRF images, by gradually increasing the incident angle of the light beam on the sample. A comprehensive theory was developed to extract the membrane/substrate separation distance from fluorescently labeled cell membranes. A straightforward image processing was then established to compute the topography of cells with a nanometric axial resolution, typically 10-20 nm. To highlight the new opportunities offered by vaTIRFM to quantify adhesion process of motile cells, adhesion of MDA-MB-231 cancer cells on glass substrate coated with fibronectin was examined. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  7. Modular architecture of eukaryotic RNase P and RNase MRP revealed by electron microscopy.

    Science.gov (United States)

    Hipp, Katharina; Galani, Kyriaki; Batisse, Claire; Prinz, Simone; Böttcher, Bettina

    2012-04-01

    Ribonuclease P (RNase P) and RNase MRP are closely related ribonucleoprotein enzymes, which process RNA substrates including tRNA precursors for RNase P and 5.8 S rRNA precursors, as well as some mRNAs, for RNase MRP. The structures of RNase P and RNase MRP have not yet been solved, so it is unclear how the proteins contribute to the structure of the complexes and how substrate specificity is determined. Using electron microscopy and image processing we show that eukaryotic RNase P and RNase MRP have a modular architecture, where proteins stabilize the RNA fold and contribute to cavities, channels and chambers between the modules. Such features are located at strategic positions for substrate recognition by shape and coordination of the cleaved-off sequence. These are also the sites of greatest difference between RNase P and RNase MRP, highlighting the importance of the adaptation of this region to the different substrates.

  8. In vivo dynamics of the cortical actin network revealed by fast-scanning atomic force microscopy.

    Science.gov (United States)

    Zhang, Yanshu; Yoshida, Aiko; Sakai, Nobuaki; Uekusa, Yoshitsugu; Kumeta, Masahiro; Yoshimura, Shige H

    2017-08-01

    Together with lamellipodia and stress fibers, a dynamic network of actin filaments in the cell cortex plays a major role in the maintenance of cell morphology and motility. In contrast to lamellipodia, which have been well studied in various motile cells, the dynamics of actin filaments in the cell cortex have not yet been clarified due to a lack of proper imaging techniques. Here, we utilized high-speed atomic force microscopy for live-cell imaging and analyzed cortical actin dynamics in living cells. We successfully measured the polymerization rate and the frequency of filament synthesis in living COS-7 cells, and examined the associated effects of various inhibitors and actin-binding proteins. Actin filaments are synthesized beneath the plasma membrane and eventually descend into the cytoplasm. The inhibitors, cytochalasin B inhibited the polymerization, while jasplakinolide, inhibited the turnover of actin filaments as well as descension of the newly synthesized filaments, suggesting that actin polymerization near the membrane drives turnover of the cortical actin meshwork. We also determined how actin turnover is maintained and regulated by the free G-actin pool and G-actin binding proteins such as profilin and thymosin β4, and found that only a small amount of free G-actin was present in the cortex. Finally, we analyzed several different cell types, and found that the mesh size and the orientation of actin filaments were highly divergent, indicating the involvement of various actin-binding proteins in the maintenance and regulation of cortical actin architecture in each cell type. © The Author 2017. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. Super-resolution microscopy reveals γ-secretase at both sides of the neuronal synapse.

    Science.gov (United States)

    Schedin-Weiss, Sophia; Caesar, Ina; Winblad, Bengt; Blom, Hans; Tjernberg, Lars O

    2016-03-31

    The transmembrane protein assembly γ-secretase is a key protease in regulated intramembrane processing (RIP) of around 100 type-1 transmembrane proteins. Importantly, it has a pathological role in Alzheimer disease (AD) as it generates the neurotoxic amyloid β-peptide from the amyloid precursor protein (APP). Studies on γ-secretase location are therefore crucial both from a biological and a therapeutic perspective. Despite several years of efforts in many laboratories, it is not clear where in the neuron γ-secretase exerts it's activities. Technical challenges include the fact that the active enzyme contains four protein components and that most subcellular compartments cannot be spatially resolved by traditional light microscopy. Here, we have used a powerful combination of the two nanoscopy techniques STORM and STED microscopy to visualize the location of γ-secretase in neurons using an active-site specific probe, with a focus on the synapse. We show that γ-secretase is present in both the pre-and postsynaptic compartments. We further show that the enzyme is enriched very close to the synaptic cleft in the postsynaptic membrane, as well as to NMDA receptors, demonstrating that γ-secretase is present in the postsynaptic plasma membrane. Importantly, the expression of γ-secretase increased in the pre- and postsynaptic compartments with the size of the synapse, suggesting a correlation between γ-secretase activity and synapse maturation. Thus, our data shows the synaptic location with high precision in three dimensions and settles the long-lasting debate on the synaptic location of γ-secretase.

  10. The precision of experienced action video-game players: line bisection reveals reduced leftward response bias.

    Science.gov (United States)

    Latham, Andrew J; Patston, Lucy L M; Tippett, Lynette J

    2014-11-01

    Twenty-two experienced action video-game players (AVGPs) and 18 non-VGPs were tested on a pen-and-paper line bisection task that was untimed. Typically, right-handers bisect lines 2 % to the left of true centre, a bias thought to reflect the dominance of the right-hemisphere for visuospatial attention. Expertise may affect this bias, with expert musicians showing no bias in line bisection performance. Our results show that experienced-AVGPs also bisect lines with no bias with their right hand and a significantly reduced bias with their left hand compared to non-AVGPs. Bisections by experienced-AVGPs were also more precise than those of non-AVGPs. These findings show the cognitive proficiencies of experienced-AVGPs can generalize beyond computer based tasks, which resemble their training environment.

  11. Superior canal dehiscence with tegmen defect revealed by otoscopy: Video clip demonstration of pulsatile tympanic membrane.

    Science.gov (United States)

    Castellucci, Andrea; Brandolini, Cristina; Piras, Gianluca; Fernandez, Ignacio Javier; Giordano, Davide; Pernice, Carmine; Modugno, Giovanni Carlo; Pirodda, Antonio; Ferri, Gian Gaetano

    2018-02-01

    Superior canal dehiscence is a pathologic condition of the otic capsule acting as aberrant window of the inner ear. It results in reduction of inner ear impedance and in abnormal exposure of the labyrinthine neuroepithelium to the action of the surrounding structures. The sum of these phenomena leads to the onset of typical cochleo-vestibular symptoms and signs. Among them, pulsatile tinnitus has been attributed to a direct transmission of intracranial vascular activities to labyrinthine fluids. We present the first video-otoscopic documentation of spontaneous pulse-synchronous movements of the tympanic membrane in two patients with superior canal dehiscence. Pulsating eardrum may represent an additional sign of third-mobile window lesion. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  12. Remodelling of cortical actin where lytic granules dock at natural killer cell immune synapses revealed by super-resolution microscopy.

    Science.gov (United States)

    Brown, Alice C N; Oddos, Stephane; Dobbie, Ian M; Alakoskela, Juha-Matti; Parton, Richard M; Eissmann, Philipp; Neil, Mark A A; Dunsby, Christopher; French, Paul M W; Davis, Ilan; Davis, Daniel M

    2011-09-01

    Natural Killer (NK) cells are innate immune cells that secrete lytic granules to directly kill virus-infected or transformed cells across an immune synapse. However, a major gap in understanding this process is in establishing how lytic granules pass through the mesh of cortical actin known to underlie the NK cell membrane. Research has been hampered by the resolution of conventional light microscopy, which is too low to resolve cortical actin during lytic granule secretion. Here we use two high-resolution imaging techniques to probe the synaptic organisation of NK cell receptors and filamentous (F)-actin. A combination of optical tweezers and live cell confocal microscopy reveals that microclusters of NKG2D assemble into a ring-shaped structure at the centre of intercellular synapses, where Vav1 and Grb2 also accumulate. Within this ring-shaped organisation of NK cell proteins, lytic granules accumulate for secretion. Using 3D-structured illumination microscopy (3D-SIM) to gain super-resolution of ~100 nm, cortical actin was detected in a central region of the NK cell synapse irrespective of whether activating or inhibitory signals dominate. Strikingly, the periodicity of the cortical actin mesh increased in specific domains at the synapse when the NK cell was activated. Two-colour super-resolution imaging revealed that lytic granules docked precisely in these domains which were also proximal to where the microtubule-organising centre (MTOC) polarised. Together, these data demonstrate that remodelling of the cortical actin mesh occurs at the central region of the cytolytic NK cell immune synapse. This is likely to occur for other types of cell secretion and also emphasises the importance of emerging super-resolution imaging technology for revealing new biology.

  13. Remodelling of cortical actin where lytic granules dock at natural killer cell immune synapses revealed by super-resolution microscopy.

    Directory of Open Access Journals (Sweden)

    Alice C N Brown

    2011-09-01

    Full Text Available Natural Killer (NK cells are innate immune cells that secrete lytic granules to directly kill virus-infected or transformed cells across an immune synapse. However, a major gap in understanding this process is in establishing how lytic granules pass through the mesh of cortical actin known to underlie the NK cell membrane. Research has been hampered by the resolution of conventional light microscopy, which is too low to resolve cortical actin during lytic granule secretion. Here we use two high-resolution imaging techniques to probe the synaptic organisation of NK cell receptors and filamentous (F-actin. A combination of optical tweezers and live cell confocal microscopy reveals that microclusters of NKG2D assemble into a ring-shaped structure at the centre of intercellular synapses, where Vav1 and Grb2 also accumulate. Within this ring-shaped organisation of NK cell proteins, lytic granules accumulate for secretion. Using 3D-structured illumination microscopy (3D-SIM to gain super-resolution of ~100 nm, cortical actin was detected in a central region of the NK cell synapse irrespective of whether activating or inhibitory signals dominate. Strikingly, the periodicity of the cortical actin mesh increased in specific domains at the synapse when the NK cell was activated. Two-colour super-resolution imaging revealed that lytic granules docked precisely in these domains which were also proximal to where the microtubule-organising centre (MTOC polarised. Together, these data demonstrate that remodelling of the cortical actin mesh occurs at the central region of the cytolytic NK cell immune synapse. This is likely to occur for other types of cell secretion and also emphasises the importance of emerging super-resolution imaging technology for revealing new biology.

  14. Ion milling coupled field emission scanning electron microscopy reveals current misunderstanding of morphology of polymeric nanoparticles.

    Science.gov (United States)

    Francis, Donny; Mouftah, Samiha; Steffen, Robert; Beduneau, Arnaud; Pellequer, Yann; Lamprecht, Alf

    2015-01-01

    Nanoparticles (NPs) are currently used as drug delivery systems for numerous therapeutic macromolecules, e.g. proteins or DNA. Based on the preparation by double emulsion solvent evaporation a sponge-like structure was postulated entrapping hydrophilic drugs inside an internal aqueous phase. However, a direct proof of this hypothesized structure is still missing today. NPs were prepared from different polymers using a double-emulsion method and characterized for their physicochemical properties. Combining ion milling with field emission scanning electron microscopy allowed to cross section single NP and to visualize their internal morphology. The imaging procedure permitted cross-sectioning of NPs and visualization of the internal structure as well as localizing drugs associated with NPs. It was observed that none of the model actives was encapsulated inside the polymeric matrix when particle diameters were below around 470 nm but predominantly adsorbed to the particle surface. Even at larger diameters only a minority of particles of a diameter below 1 μm contained an internal phase. The properties of such drug loaded NPs, i.e. drug release or the observations in cellular uptake or even drug targeting needs to be interpreted carefully since in most cases NP surface properties are potentially dominated by the 'encapsulated' drug characteristics. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Nanoscale Electronic Inhomogeneity in In_2Se_3 Nanoribbons Revealed by Microwave Impedance Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lai, K.J.

    2010-06-02

    Driven by interactions due to the charge, spin, orbital, and lattice degrees of freedom, nanoscale inhomogeneity has emerged as a new theme for materials with novel properties near multiphase boundaries. As vividly demonstrated in complex metal oxides and chalcogenides, these microscopic phases are of great scientific and technological importance for research in hightemperature superconductors, colossal magnetoresistance effect, phase-change memories, and domain switching operations. Direct imaging on dielectric properties of these local phases,however, presents a big challenge for existing scanning probe techniques. Here, we report the observation of electronic inhomogeneity in indium selenide (In{sub 2}Se{sub 3}) nanoribbons by near-field scanning microwave impedance microscopy. Multiple phases with local resistivity spanning six orders of magnitude are identified as the coexistence of superlattice, simple hexagonal lattice and amorphous structures with {approx}100nm inhomogeneous length scale, consistent with high-resolution transmission electron microscope studies. The atomic-force-microscope-compatible microwave probe is able to perform quantitative sub-surface electronic study in a noninvasive manner. Finally, the phase change memory function in In{sub 2}Se{sub 3} nanoribbon devices can be locally recorded with big signal of opposite signs.

  16. Piezo-generated charge mapping revealed through direct piezoelectric force microscopy.

    Science.gov (United States)

    Gomez, A; Gich, M; Carretero-Genevrier, A; Puig, T; Obradors, X

    2017-10-24

    While piezoelectric and ferroelectric materials play a key role in many everyday applications, there are still a number of open questions related to their physics. To enhance our understanding of piezoelectrics and ferroelectrics, nanoscale characterization is essential. Here, we develop an atomic force microscopy based mode that obtains a direct quantitative analysis of the piezoelectric coefficient d33. We report nanoscale images of piezogenerated charge in a thick single crystal of periodically poled lithium niobate (PPLN), a bismuth ferrite (BiFO3) thin film, and lead zirconate titanate (PZT) by applying a force and recording the current produced by these materials. The quantification of d33 coefficients for PPLN (14 ± 3 pC per N) and BFO (43 ± 6 pC per N) is in agreement with the values reported in the literature. Even stronger evidence of the reliability of the method is provided by an equally accurate measurement of the significantly larger d33 of PZT.

  17. High-Speed Atomic Force Microscopy Revealing Contamination in DNA Purification Systems.

    Science.gov (United States)

    Mikheikin, Andrey; Olsen, Anita; Picco, Loren; Payton, Oliver; Mishra, Bud; Gimzewski, James K; Reed, Jason

    2016-03-01

    Motivated by reports of low-level DNA contamination in popular commercial DNA purification kits, we employed a novel high-speed atomic force microscopy (HS-AFM) method to detect and characterize particulate and polymeric contaminants in four such systems: Qiagen MinElute PCR Purification, Zymo Research DNA Clean and Concentrator-5, Invitrogen ChargeSwitch-Pro PCR Purification, and Beckman Coulter AMPure XP. HS-AFM avoids amplification artifacts present in PCR or in the sequencing of amplified products, and it requires no chemical labels and easily achieves near-single-molecule sensitivity. Using this technique, we found trace levels of filamentous contamination, similar in appearance to dsDNA, in eluates from the Zymo, Qiagen, and ChargeSwitch kits. Conversely, we detected no contaminants in magnetic bead-based AMPure XP solutions. Eluates from the Zymo kits also tested positive for DNA in fluorescent intercalator dye and whole genome amplification (WGA) assays. Qiagen kits tested positive in the fluorescence assay but negative in the WGA assay. Both ChargeSwitch and AMPure XP tested negative in the fluorescence assay while the WGA results for these two kits were ambiguous. Taken together, our findings suggest AMPure XP would be the best choice for analyses requiring very high analytical stringency. While HS-AFM alone does not provide chemical specificity, it is a potentially valuable tool for characterizing and quantifying trace contaminants in molecular biology reagents and instruments in cases where conventional techniques fail.

  18. Features of Blastocystis spp. in xenic culture revealed by deconvolutional microscopy.

    Science.gov (United States)

    Nagel, Robyn; Gray, Christian; Bielefeldt-Ohmann, Helle; Traub, Rebecca J

    2015-09-01

    Blastocystis spp. are common human enteric parasites with complex morphology and have been reported to cause irritable bowel syndrome (IBS). Deconvolutional microscopy with time-lapse imaging and fluorescent spectroscopy of xenic cultures of Blastocystis spp. from stool samples of IBS patients and from asymptomatic, healthy pigs allowed observations of living organisms in their natural microbial environment. Blastocystis organisms of the vacuolated, granular, amoebic and cystic forms were observed to autofluorescence in the 557/576 emission spectra. Autofluorescence could be distinguished from fluorescein-conjugated Blastocystis-specific antibody labelling in vacuolated and granular forms. This antibody labelled Blastocystis subtypes 1, 3 and 4 but not 5. Surface pores of 1 μm in diameter were observed cyclically opening and closing over 24 h. Vacuolated forms extruded a viscous material from a single surface point with coincident deflation that may demonstrate osmoregulation. Tear-shaped granules were observed exiting from the surface of an amoebic form, but their origin and identity remain unknown.

  19. High-speed atomic force microscopy reveals structural dynamics of amyloid β1-42 aggregates.

    Science.gov (United States)

    Watanabe-Nakayama, Takahiro; Ono, Kenjiro; Itami, Masahiro; Takahashi, Ryoichi; Teplow, David B; Yamada, Masahito

    2016-05-24

    Aggregation of amyloidogenic proteins into insoluble amyloid fibrils is implicated in various neurodegenerative diseases. This process involves protein assembly into oligomeric intermediates and fibrils with highly polymorphic molecular structures. These structural differences may be responsible for different disease presentations. For this reason, elucidation of the structural features and assembly kinetics of amyloidogenic proteins has been an area of intense study. We report here the results of high-speed atomic force microscopy (HS-AFM) studies of fibril formation and elongation by the 42-residue form of the amyloid β-protein (Aβ1-42), a key pathogenetic agent of Alzheimer's disease. Our data demonstrate two different growth modes of Aβ1-42, one producing straight fibrils and the other producing spiral fibrils. Each mode depends on initial fibril nucleus structure, but switching from one growth mode to another was occasionally observed, suggesting that fibril end structure fluctuated between the two growth modes. This switching phenomenon was affected by buffer salt composition. Our findings indicate that polymorphism in fibril structure can occur after fibril nucleation and is affected by relatively modest changes in environmental conditions.

  20. Quantitative analyses of RAG-RSS interactions and conformations revealed by atomic force microscopy.

    Science.gov (United States)

    Pavlicek, Jeffrey W; Lyubchenko, Yuri L; Chang, Yung

    2008-10-28

    During V(D)J recombination, site specific DNA excision is dictated by the binding of RAG1/2 proteins to the conserved recombination signal sequence (RSS) within the genome. The interaction between RAG1/2 and RSS is thought to involve a large DNA distortion that is permissive for DNA cleavage. In this study, using atomic force microscopy imaging (AFM), we analyzed individual RAG-RSS complexes, in which the bending angle of RAG-associated RSS substrates could be visualized and quantified. We provided the quantitative measurement on the conformations of specific RAG-12RSS complexes. Previous data indicating the necessity of RAG2 for recombination implies a structural role in the RAG-RSS complex. Surprisingly, however, no significant difference was observed in conformational bending with AFM between RAG1-12RSS and RAG1/2-12RSS. RAG1 was found sufficient to induce DNA bending, and the addition of RAG2 did not change the bending profile. In addition, a prenicked 12RSS bound by RAG1/2 proteins displayed a conformation similar to the one observed with the intact 12RSS, implying that no greater DNA bending occurs after the nicking step in the signal complex. Taken together, the quantitative AFM results on the components of the recombinase emphasize a tightly held complex with a bend angle value near 60 degrees , which may be a prerequisite step for the site-specific nicking by the V(D)J recombinase.

  1. Structure of Human M-type Phospholipase A2 Receptor Revealed by Cryo-Electron Microscopy.

    Science.gov (United States)

    Dong, Yue; Cao, Longxing; Tang, Hua; Shi, Xiangyi; He, Yongning

    2017-12-08

    M-type phospholipase A2 receptor (M-PLA2R) is a member of the mannose receptor family and known as the receptor of secretory phospholipase A2s. It has also been identified as the major autoantigen of idiopathic membranous nephropathy, one of the most common causes for nephrotic syndrome in adults. Here we determine the structure of human M-PLA2R ectodomain by cryo-electron microscopy. The results show that the ectodomain has high internal flexibility and forms a compact dual-ring-shaped conformation at acidic pH and adopts extended conformations at basic pH. The inter-domain interactions of human M-PLA2R are explored by the binding studies with individual domains, showing the mechanism of the conformational change. In addition, the biochemical data suggest that mouse M-PLA2R recognizes mouse secretory phospholipase A2-G1B only at physiological or basic pH, rather than at acidic pH. These results suggest that the pH-dependent conformational change might play important roles in the functional activities of M-PLA2R such as ligand binding and release, and may also be relevant to the immunogenicity in membranous nephropathy. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Quaternary organization of a phytochrome dimer as revealed by cryoelectron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Li, H.; Li, H.; Zhang, J.; Vierstra, R. D.

    2010-06-15

    Phytochromes are a collection of dimeric photoreceptors that direct a diverse array of responses in plants and microorganisms through photoconversion between a red light-absorbing ground state Pr, and a far-red light-absorbing photoactivated state Pfr. Photoconversion from Pr to Pfr is initiated by a light-driven rotation within the covalently attached bilin, which then triggers a series of protein conformational changes in the binding pocket. These movements ultimately affect an appended output module, which often has reversible protein kinase activity. Propagation of the light signal from the bilin to the output module likely depends on the dimerization interface but its architecture and response to phototransformation remain unclear. Here, we used single particle cryoelectron microscopy to determine the quaternary arrangement of the phytochrome dimer as Pr, using the bacteriophytochrome (BphP) from Deinococcus radiodurans. Contrary to the long-standing view that the two monomers are held together solely via their C-terminal region, we provide unambiguous evidence that the N-terminal bilin-binding region of BphP also provides a dimerization interface with the C-terminal kinase domain appearing as a more flexible appendage. The BphP monomers dimerize in parallel with the polypeptides intimately twisting around each other in a right-handed fashion. Based on this electron microscopic picture, we propose that the light-driven conformational changes transmitted from the chromophore to the output module along the spine of this extensive dimer interface is the central feature underpinning phytochrome signaling.

  3. Contributions of the lower dimer to supramolecular actin patterning revealed by TIRF microscopy.

    Science.gov (United States)

    Silván, Unai; Hyotyla, Janne; Mannherz, Hans-Georg; Ringler, Philippe; Müller, Shirley A; Aebi, Ueli; Maier, Timm; Schoenenberger, Cora-Ann

    2016-08-01

    Two distinct dimers are formed during the initial steps of actin polymerization. The first one, referred to as the 'lower dimer' (LD) was discovered many years ago by means of chemical crosslinking. Owing to its transient nature, a biological relevance had long been precluded when, using LD-specific antibodies, we detected LD-like contacts in actin assemblies that are associated with the endolysosomal compartment in a number of different cell lines. Moreover, immunofluorescence showed the presence of LD-related structures at the cell periphery of migrating fibroblasts, in the nucleus, and in association with the centrosome of interphase cells. Here, we explore contributions of the LD to the assembly of supramolecular actin structures in real time by total internal reflection fluorescence (TIRF) microscopy. Our data shows that while LD on its own cannot polymerize under filament forming conditions, it is able to incorporate into growing F-actin filaments. This incorporation of LD triggers the formation of X-shaped filament assemblies with barbed ends that are pointing in the same direction in the majority of cases. Similarly, an increased frequency of junction sites was observed when filaments were assembled in the presence of oxidized actin. This data suggests that a disulfide bridge between Cys374 residues might stabilize LD-contacts. Based on our findings, we propose two possible models for the molecular mechanism underlying the supramolecular actin patterning in LD-related structures. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Faceting, composition and crystal phase evolution in III-V antimonide nanowire heterostructures revealed by combining microscopy techniques

    Science.gov (United States)

    Xu, Tao; Dick, Kimberly A.; Plissard, Sébastien; Hai Nguyen, Thanh; Makoudi, Younes; Berthe, Maxime; Nys, Jean-Philippe; Wallart, Xavier; Grandidier, Bruno; Caroff, Philippe

    2012-03-01

    III-V antimonide nanowires are among the most interesting semiconductors for transport physics, nanoelectronics and long-wavelength optoelectronic devices due to their optimal material properties. In order to investigate their complex crystal structure evolution, faceting and composition, we report a combined scanning electron microscopy (SEM), transmission electron microscopy (TEM), and scanning tunneling microscopy (STM) study of gold-nucleated ternary InAs/InAs1-xSbx nanowire heterostructures grown by molecular beam epitaxy. SEM showed the general morphology and faceting, TEM revealed the internal crystal structure and ternary compositions, while STM was successfully applied to characterize the oxide-free nanowire sidewalls, in terms of nanofaceting morphology, atomic structure and surface composition. The complementary use of these techniques allows for correlation of the morphological and structural properties of the nanowires with the amount of Sb incorporated during growth. The addition of even a minute amount of Sb to InAs changes the crystal structure from perfect wurtzite to perfect zinc blende, via intermediate stacking fault and pseudo-periodic twinning regimes. Moreover, the addition of Sb during the axial growth of InAs/InAs1-xSbx heterostructure nanowires causes a significant conformal lateral overgrowth on both segments, leading to the spontaneous formation of a core-shell structure, with an Sb-rich shell.

  5. [Revealing the Cell Structure and Formation of Bamboo with Confocal Raman Microscopy].

    Science.gov (United States)

    Li, Xiao-li; Zhou, Bin-xiong; Zhang, Yi; Yao, Yan-ming; He, Yong

    2016-02-01

    Parenchyma cell (PAC), transition tissue between parenchyma cell and fiber cell (TC) and fibre cell (FC) of bamboo were studied by confocal Raman microscopy in this paper. Partial least squares regression was applied to establish a quantitative differentiation model for the three types of cells. The result showed that the determination coefficients (R²) of calibration and validation were respectively 0.810 and 0.800, and the root mean square error (RMSE) were respectively 0.323 and 0.332. What's more, three raman bands of 1,095, 1,319 and 1,636 cm⁻¹, verified to the characteristic peaks of pectin, hemicellulose and lignin, were found to be the important bands for the differentiation. Subsequently, these three raman bands were used to establish a multiple linear regression (MLR) model, and the determination coefficients (R²) of calibration and validation of the model were respectively 0.644 and 0.643, and the root mean square error (RMSE) were respectively 0.442 and 0.443. This result showed that there existed obvious difference among the three types of cells in these three raman bands. Finally, the raman spectral signal processed by wavelet transform to eliminate baseline were used to chemical imaging analysis. These results showed a rather large microfibril angle between cellulose fibrils and fibre axis, which contributed to higher modulus and hardness of cells. Hemicellulose and cellulose have similar distribution in the raman chemical image, due to the connection of hemicellulose and cellulose microfiber through hydrogen bond and the closely combination under the action of van der Waals force. The cell corners (CC) and compound middle lamella (CML) were heavily lignified, and a gradual decrease of lignification from the outer layer to the inner layer of the three cells indicate that lignification was first occurred at the CC and CML, and the lignification was not fully completed.

  6. External morphogenesis of the tardigrade Hypsibius dujardini as revealed by scanning electron microscopy.

    Science.gov (United States)

    Gross, Vladimir; Minich, Irene; Mayer, Georg

    2017-04-01

    Tardigrada, commonly called water bears, is a taxon of microscopic panarthropods with five-segmented bodies and four pairs of walking legs. Although tardigrades have been known to science for several centuries, questions remain regarding many aspects of their biology, such as embryogenesis. Herein, we used scanning electron microscopy to document the external changes that occur during embryonic development in the tardigrade Hypsibius dujardini (Eutardigrada, Parachela, Hypsibiidae). Our results show an accelerated development of external features, with approximately 30 hrs separating the point at which external structures first become recognizable and a fully formed embryo. All segments appear to arise simultaneously between ∼20 and 25 hrs of development, and no differences in the degree of development could be detected between the limb buds at any stage. Claws emerge shortly after the limb buds and are morphologically similar to those of adults. The origin of the claws is concurrent with that of the sclerotized parts of the mouth, suggesting that all cuticular structures arise simultaneously at ∼30 hrs. The mouth arises as an invagination in the terminal region of the head at ∼25 hrs, closes later in development, and opens again shortly before hatching. The anlagen of the peribuccal lobes arise as one dorsal and one ventral row, each consisting of three lobes, and later form a ring in the late embryo, whereas there is no indication of a labrum anlage at any point during development. Furthermore, we describe limited postembryonic development in the form of cuticular pores that are absent in juveniles but present in adults. This study represents the first scanning electron micrographs of tardigrade embryos, demonstrating the utility of this technique for studying embryogenesis in tardigrades. This work further adds an external morphological perspective to the developmental data already available for H. dujardini, facilitating future comparisons to related

  7. Revealing the reaction mechanisms of Li-O2 batteries using environmental transmission electron microscopy

    Science.gov (United States)

    Luo, Langli; Liu, Bin; Song, Shidong; Xu, Wu; Zhang, Ji-Guang; Wang, Chongmin

    2017-07-01

    The performances of a Li-O2 battery depend on a complex interplay between the reaction mechanism at the cathode, the chemical structure and the morphology of the reaction products, and their spatial and temporal evolution; all parameters that, in turn, are dependent on the choice of the electrolyte. In an aprotic cell, for example, the discharge product, Li2O2, forms through a combination of solution and surface chemistries that results in the formation of a baffling toroidal morphology. In a solid electrolyte, neither the reaction mechanism at the cathode nor the nature of the reaction product is known. Here we report the full-cycle reaction pathway for Li-O2 batteries and show how this correlates with the morphology of the reaction products. Using aberration-corrected environmental transmission electron microscopy (TEM) under an oxygen environment, we image the product morphology evolution on a carbon nanotube (CNT) cathode of a working solid-state Li-O2 nanobattery and correlate these features with the electrochemical reaction at the electrode. We find that the oxygen-reduction reaction (ORR) on CNTs initially produces LiO2, which subsequently disproportionates into Li2O2 and O2. The release of O2 creates a hollow nanostructure with Li2O outer-shell and Li2O2 inner-shell surfaces. Our findings show that, in general, the way the released O2 is accommodated is linked to lithium-ion diffusion and electron-transport paths across both spatial and temporal scales; in turn, this interplay governs the morphology of the discharging/charging products in Li-O2 cells.

  8. 5D imaging via light sheet microscopy reveals cell dynamics during the eye-antenna disc primordium formation in Drosophila

    Science.gov (United States)

    Huang, Yu Shan; Ku, Hui Yu; Tsai, Yun Chi; Chang, Chin Hao; Pao, Sih Hua; Sun, Y. Henry; Chiou, Arthur

    2017-03-01

    5D images of engrailed (en) and eye gone (eyg) gene expressions during the course of the eye-antenna disc primordium (EADP) formation of Drosophila embryos from embryonic stages 13 through 16 were recorded via light sheet microscopy and analyzed to reveal the cell dynamics involved in the development of the EADP. Detailed analysis of the time-lapsed images revealed the process of EADP formation and its invagination trajectory, which involved an inversion of the EADP anterior-posterior axis relative to the body. Furthermore, analysis of the en-expression pattern in the EADP provided strong evidence that the EADP is derived from one of the en-expressing head segments.

  9. Significantly improved precision of cell migration analysis in time-lapse video microscopy through use of a fully automated tracking system

    Directory of Open Access Journals (Sweden)

    Seufferlein Thomas

    2010-04-01

    Full Text Available Abstract Background Cell motility is a critical parameter in many physiological as well as pathophysiological processes. In time-lapse video microscopy, manual cell tracking remains the most common method of analyzing migratory behavior of cell populations. In addition to being labor-intensive, this method is susceptible to user-dependent errors regarding the selection of "representative" subsets of cells and manual determination of precise cell positions. Results We have quantitatively analyzed these error sources, demonstrating that manual cell tracking of pancreatic cancer cells lead to mis-calculation of migration rates of up to 410%. In order to provide for objective measurements of cell migration rates, we have employed multi-target tracking technologies commonly used in radar applications to develop fully automated cell identification and tracking system suitable for high throughput screening of video sequences of unstained living cells. Conclusion We demonstrate that our automatic multi target tracking system identifies cell objects, follows individual cells and computes migration rates with high precision, clearly outperforming manual procedures.

  10. Teaching microsurgery to undergraduate medical students by means of high-definition stereo video microscopy: the Aachen skills lab experience

    Science.gov (United States)

    Ilgner, Justus; Park, Jonas Jae-Hyun; Westhofen, Martin

    2008-02-01

    Introduction: The master plan for innovative medical education established at RWTH Aachen Medical Faculty helped to set up an inter-disciplinary, interactive teaching environment for undergraduate medical students during their clinical course. This study presents our first experience with teaching microsurgery to medical students by means of highdefinition stereo video monitoring. Material and methods: A plastic model created for ear inspection with a handheld otoscope was modified with an exchangeable membrane resembling an eardrum plus a model of the human cochlea. We attached a 1280×1024 HD stereo camera to an operating microscope, whose images were processed online by a PC workstation. The live image was displayed by two LCD projectors @ 1280×720 pixels on a 1,25m rear-projection screen by polarized filters. Each medical student was asked to perform standard otosurgical procedures (paracentesis and insertion of grommets; insertion of a cochlear implant electrode) being guided by the HD stereoscopic video image. Results: Students quickly adopted this method of training, as all attendants shared the same high-definition stereoscopic image. The learning process of coordinating hand movement with visual feedback was regarded being challenging as well as instructive by all students. Watching the same image facilitated valuable feedback from the audience for each student performing his tasks. All students noted that this course made them feel more confident in their manual skills and that they would consider a career in a microsurgical specialty. Conclusion: High definition stereoscopy provides an easy access to microsurgical techniques for undergraduate medical students. This access not only bears the potential to compress the learning curve for junior doctors during their clinical training but also helps to attract medical students to a career in a microsurgical specialty.

  11. Skyrmion Hall effect revealed by direct time-resolved X-ray microscopy

    Science.gov (United States)

    Litzius, Kai; Lemesh, Ivan; Krüger, Benjamin; Bassirian, Pedram; Caretta, Lucas; Richter, Kornel; Büttner, Felix; Sato, Koji; Tretiakov, Oleg A.; Förster, Johannes; Reeve, Robert M.; Weigand, Markus; Bykova, Iuliia; Stoll, Hermann; Schütz, Gisela; Beach, Geoffrey S. D.; Kläui, Mathias

    2017-02-01

    Magnetic skyrmions are promising candidates for future spintronic applications such as skyrmion racetrack memories and logic devices. They exhibit exotic and complex dynamics governed by topology and are less influenced by defects, such as edge roughness, than conventionally used domain walls. In particular, their non-zero topological charge leads to a predicted `skyrmion Hall effect', in which current-driven skyrmions acquire a transverse velocity component analogous to charged particles in the conventional Hall effect. Here, we use nanoscale pump-probe imaging to reveal the real-time dynamics of skyrmions driven by current-induced spin-orbit torques. We find that skyrmions move at a well-defined angle ΘSkH that can exceed 30° with respect to the current flow, but in contrast to conventional theoretical expectations, ΘSkH increases linearly with velocity up to at least 100 ms-1. We qualitatively explain our observation based on internal mode excitations in combination with a field-like spin-orbit torque, showing that one must go beyond the usual rigid skyrmion description to understand the dynamics.

  12. Live-cell microscopy reveals small molecule inhibitor effects on MAPK pathway dynamics.

    Directory of Open Access Journals (Sweden)

    Daniel J Anderson

    Full Text Available Oncogenic mutations in the mitogen activated protein kinase (MAPK pathway are prevalent in human tumors, making this pathway a target of drug development efforts. Recently, ATP-competitive Raf inhibitors were shown to cause MAPK pathway activation via Raf kinase priming in wild-type BRaf cells and tumors, highlighting the need for a thorough understanding of signaling in the context of small molecule kinase inhibitors. Here, we present critical improvements in cell-line engineering and image analysis coupled with automated image acquisition that allow for the simultaneous identification of cellular localization of multiple MAPK pathway components (KRas, CRaf, Mek1 and Erk2. We use these assays in a systematic study of the effect of small molecule inhibitors across the MAPK cascade either as single agents or in combination. Both Raf inhibitor priming as well as the release from negative feedback induced by Mek and Erk inhibitors cause translocation of CRaf to the plasma membrane via mechanisms that are additive in pathway activation. Analysis of Erk activation and sub-cellular localization upon inhibitor treatments reveals differential inhibition and activation with the Raf inhibitors AZD628 and GDC0879 respectively. Since both single agent and combination studies of Raf and Mek inhibitors are currently in the clinic, our assays provide valuable insight into their effects on MAPK signaling in live cells.

  13. High-speed atomic force microscopy reveals structural dynamics of α -synuclein monomers and dimers

    Science.gov (United States)

    Zhang, Yuliang; Hashemi, Mohtadin; Lv, Zhengjian; Williams, Benfeard; Popov, Konstantin I.; Dokholyan, Nikolay V.; Lyubchenko, Yuri L.

    2018-03-01

    α-Synuclein (α-syn) is the major component of the intraneuronal inclusions called Lewy bodies, which are the pathological hallmark of Parkinson's disease. α-Syn is capable of self-assembly into many different species, such as soluble oligomers and fibrils. Even though attempts to resolve the structures of the protein have been made, detailed understanding about the structures and their relationship with the different aggregation steps is lacking, which is of interest to provide insights into the pathogenic mechanism of Parkinson's disease. Here we report the structural flexibility of α-syn monomers and dimers in an aqueous solution environment as probed by single-molecule time-lapse high-speed AFM. In addition, we present the molecular basis for the structural transitions using discrete molecular dynamics (DMD) simulations. α-Syn monomers assume a globular conformation, which is capable of forming tail-like protrusions over dozens of seconds. Importantly, a globular monomer can adopt fully extended conformations. Dimers, on the other hand, are less dynamic and show a dumbbell conformation that experiences morphological changes over time. DMD simulations revealed that the α-syn monomer consists of several tightly packed small helices. The tail-like protrusions are also helical with a small β-sheet, acting as a "hinge". Monomers within dimers have a large interfacial interaction area and are stabilized by interactions in the non-amyloid central (NAC) regions. Furthermore, the dimer NAC-region of each α-syn monomer forms a β-rich segment. Moreover, NAC-regions are located in the hydrophobic core of the dimer.

  14. Live, video-rate super-resolution microscopy using structured illumination and rapid GPU-based parallel processing.

    Science.gov (United States)

    Lefman, Jonathan; Scott, Keana; Stranick, Stephan

    2011-04-01

    Structured illumination fluorescence microscopy is a powerful super-resolution method that is capable of achieving a resolution below 100 nm. Each super-resolution image is computationally constructed from a set of differentially illuminated images. However, real-time application of structured illumination microscopy (SIM) has generally been limited due to the computational overhead needed to generate super-resolution images. Here, we have developed a real-time SIM system that incorporates graphic processing unit (GPU) based in-line parallel processing of raw/differentially illuminated images. By using GPU processing, the system has achieved a 90-fold increase in processing speed compared to performing equivalent operations on a multiprocessor computer--the total throughput of the system is limited by data acquisition speed, but not by image processing. Overall, more than 350 raw images (16-bit depth, 512 × 512 pixels) can be processed per second, resulting in a maximum frame rate of 39 super-resolution images per second. This ultrafast processing capability is used to provide immediate feedback of super-resolution images for real-time display. These developments are increasing the potential for sophisticated super-resolution imaging applications.

  15. Revealing the reaction mechanisms of Li–O2 batteries using environmental transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Langli; Liu, Bin; Song, Shidong; Xu, Wu; Zhang, Ji-Guang; Wang, Chongmin

    2017-03-27

    The capacity, Coulombic efficiency, rate, and cyclability of a Li-O2 battery critically depend on the electrode reaction mechanism and the structure/morphology of the reaction product as well as their spatial and temporal evolution1-8, which are all further complicated by the choice of different electrolyte. For the case of aprotic cell, the discharge product, Li2O2, is formed through solution and surface mechanisms9,10, but little is known on the formation mechanism of the perplexing morphology of the reaction product11-15. For the case of Li-O2 battery using solid electrolyte, neither electrode reaction mechanism nor the nature of the reaction production is known. Herein, we reveal the full cycle reaction pathway for Li-O2 batteries and its correlation with the nature of the reaction product. Using an aberration-corrected environmental TEM under oxygen environment, we captured, for the first time, the morphology and phase evolution on the carbon nanotube (CNT) cathode of a working solid-state Li-O2 nano-battery16 and directly correlated these features with electrochemical reaction. We found that the oxygen reduction reaction on CNTs initially produces LiO2, which subsequently evolves to Li2O2 and O2 through disproportionation reaction. Surprisingly it is just the releasing of O2 that inflates the particles to a hollow structure with a Li2O outer surface layer and Li2O2 inner-shell, demonstrating that, in general, accommodation of the released O2 coupled with the Li+ ion diffusion and electron transport paths across both spatial and temporal scales critically governs the morphology of the discharging/charging product in Li-O2 system. We anticipate that the direct observation of Li-O2 reaction mechanisms and their correlation with the morphology of the reaction product set foundation for quantitative understanding/modeling of the electrochemical processes in the Li-O2 system, enabling rational design of both solid-state and aprotic Li-O2 batteries.

  16. Dengue Virus and Its Relation to Human Glycoprotein IIb/IIIa Revealed by Fluorescence Microscopy and Flow Cytometry.

    Science.gov (United States)

    Attatippaholkun, Nattapol; U-Pratya, Yaowalak; Supraditaporn, Panthipa; Lorthongpanich, Chanchao; Pattanapanyasat, Kovit; Issaragrisil, Surapol

    2017-11-01

    Understanding dengue virus (DENV)-induced hemorrhage remains a challenging jigsaw puzzle with many pieces missing to understand the complex interactions between DENV and blood coagulation system. To use flow cytometry studying the interactions between DENV and human platelet aggregation receptor, glycoprotein IIb/IIIa (gpIIb/IIIa), directly conjugated fluorochrome monoclonal antibody (mAb) is essential to facilitate multifluorochrome immunostaining. However, the obstacle was that no directly conjugated fluorochrome-anti-DENV mAb had been commercially available. To overcome, we directly conjugated fluorochrome to a primary anti-DENV mAb using a LYNX rapid conjugation kit. Flow cytometry analysis showed that this conjugated antibody and anti-gpIIb/IIIa mAb were able to detect DENV and CD41a simultaneously. Fluorescence microscopy analysis further demonstrated CD41a superficially and DENV intracellularly. Potentially, this strategy can facilitate virologists for directly conjugating any virus-specific primary antibodies, which are not commercially available with fluorochrome, to study the infectivity in any surface marker-specific hosts through flow cytometry. Together, DENV can interact with both human gpIIb/IIIa(-) and gpIIb/IIIa(+) cells revealed by flow cytometry and fluorescence microscopy for the first time.

  17. Atomic force microscopy measurements reveal multiple bonds between Helicobacter pylori blood group antigen binding adhesin and Lewis b ligand.

    Science.gov (United States)

    Parreira, P; Shi, Q; Magalhaes, A; Reis, C A; Bugaytsova, J; Borén, T; Leckband, D; Martins, M C L

    2014-12-06

    The strength of binding between the Helicobacter pylori blood group antigen-binding adhesin (BabA) and its cognate glycan receptor, the Lewis b blood group antigen (Le(b)), was measured by means of atomic force microscopy. High-resolution measurements of rupture forces between single receptor-ligand pairs were performed between the purified BabA and immobilized Le(b) structures on self-assembled monolayers. Dynamic force spectroscopy revealed two similar but statistically different bond populations. These findings suggest that the BabA may form different adhesive attachments to the gastric mucosa in ways that enhance the efficiency and stability of bacterial adhesion. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  18. Golgi twins in late mitosis revealed by genetically encoded tags for live cell imaging and correlated electron microscopy

    Science.gov (United States)

    Gaietta, Guido M.; Giepmans, Ben N. G.; Deerinck, Thomas J.; Smith, W. Bryan; Ngan, Lucy; Llopis, Juan; Adams, Stephen R.; Tsien, Roger Y.; Ellisman, Mark H.

    2006-01-01

    Combinations of molecular tags visible in light and electron microscopes become particularly advantageous in the analysis of dynamic cellular components like the Golgi apparatus. This organelle disassembles at the onset of mitosis and, after a sequence of poorly understood events, reassembles after cytokinesis. The precise location of Golgi membranes and resident proteins during mitosis remains unclear, partly due to limitations of molecular markers and the resolution of light microscopy. We generated a fusion consisting of the first 117 residues of α-mannosidase II tagged with a fluorescent protein and a tetracysteine motif. The mannosidase component guarantees docking into the Golgi membrane, with the tags exposed in the lumen. The fluorescent protein is optically visible without further treatment, whereas the tetracysteine tag can be reduced acutely with a membrane-permeant phosphine, labeled with ReAsH, monitored in the light microscope, and used to trigger the photoconversion of diaminobenzidine, allowing 4D optical recording on live cells and correlated ultrastructural analysis by electron microscopy. These methods reveal that Golgi reassembly is preceded by the formation of four colinear clusters at telophase, two per daughter cell. Within each daughter, the smaller cluster near the midbody gradually migrates to rejoin the major cluster on the far side of the nucleus and asymmetrically reconstitutes a single Golgi apparatus, first in one daughter cell and then in the other. Our studies provide previously undescribed insights into Golgi disassociation and reassembly during mitosis and offer a powerful approach to follow recombinant protein distribution in 4D imaging and correlated high-resolution analysis. PMID:17101980

  19. Super-resolution microscopy reveals the insulin-resistance-regulated reorganization of GLUT4 on plasma membranes.

    Science.gov (United States)

    Gao, Lan; Chen, Junling; Gao, Jing; Wang, Hongda; Xiong, Wenyong

    2017-01-15

    GLUT4 (also known as SLC2A4) is essential for glucose uptake in skeletal muscles and adipocytes, which play central roles in whole-body glucose metabolism. Here, using direct stochastic optical reconstruction microscopy (dSTORM) to investigate the characteristics of plasma-membrane-fused GLUT4 at the single-molecule level, we have demonstrated that insulin and insulin resistance regulate the spatial organization of GLUT4 in adipocytes. Stimulation with insulin shifted the balance of GLUT4 on the plasma membrane toward a more dispersed configuration. In contrast, insulin resistance induced a more clustered distribution of GLUT4 and increased the mean number of molecules per cluster. Furthermore, our data demonstrate that the F 5 QQI motif and lipid rafts mediate the maintenance of GLUT4 clusters on the plasma membrane. Mutation of F 5 QQI (F 5 QQA-GLUT4) induced a more clustered distribution of GLUT4; moreover, destruction of lipid rafts in adipocytes expressing F 5 QQA-GLUT4 dramatically decreased the percentage of large clusters and the mean number of molecules per cluster. In conclusion, our data clarify the effects of insulin stimulation or insulin resistance on GLUT4 reorganization on the plasma membrane and reveal new pathogenic mechanisms of insulin resistance. © 2017. Published by The Company of Biologists Ltd.

  20. Light and Electron Microscopy of the European Beaver (Castor fiber) Stomach Reveal Unique Morphological Features with Possible General Biological Significance

    Science.gov (United States)

    Petryński, Wojciech; Palkowska, Katarzyna; Prusik, Magdalena; Targońska, Krystyna; Giżejewski, Zygmunt; Przybylska-Gornowicz, Barbara

    2014-01-01

    Anatomical, histological, and ultrastructural studies of the European beaver stomach revealed several unique morphological features. The prominent attribute of its gross morphology was the cardiogastric gland (CGG), located near the oesophageal entrance. Light microscopy showed that the CGG was formed by invaginations of the mucosa into the submucosa, which contained densely packed proper gastric glands comprised primarily of parietal and chief cells. Mucous neck cells represented stomach lumen. These data suggest that chief cells in the CGG develop from undifferentiated cells that migrate through the gastric gland neck rather than from mucous neck cells. Classical chief cell formation (i.e., arising from mucous neck cells) occurred in the mucosa lining the stomach lumen, however. The muscularis around the CGG consisted primarily of skeletal muscle tissue. The cardiac region was rudimentary while the fundus/corpus and pyloric regions were equally developed. Another unusual feature of the beaver stomach was the presence of specific mucus with a thickness up to 950 µm (in frozen, unfixed sections) that coated the mucosa. Our observations suggest that the formation of this mucus is complex and includes the secretory granule accumulation in the cytoplasm of pit cells, the granule aggregation inside cells, and the incorporation of degenerating cells into the mucus. PMID:24727802

  1. Light and electron microscopy of the European beaver (Castor fiber stomach reveal unique morphological features with possible general biological significance.

    Directory of Open Access Journals (Sweden)

    Natalia Ziółkowska

    Full Text Available Anatomical, histological, and ultrastructural studies of the European beaver stomach revealed several unique morphological features. The prominent attribute of its gross morphology was the cardiogastric gland (CGG, located near the oesophageal entrance. Light microscopy showed that the CGG was formed by invaginations of the mucosa into the submucosa, which contained densely packed proper gastric glands comprised primarily of parietal and chief cells. Mucous neck cells represented <0.1% of cells in the CGG gastric glands and 22-32% of cells in the proper gastric glands of the mucosa lining the stomach lumen. These data suggest that chief cells in the CGG develop from undifferentiated cells that migrate through the gastric gland neck rather than from mucous neck cells. Classical chief cell formation (i.e., arising from mucous neck cells occurred in the mucosa lining the stomach lumen, however. The muscularis around the CGG consisted primarily of skeletal muscle tissue. The cardiac region was rudimentary while the fundus/corpus and pyloric regions were equally developed. Another unusual feature of the beaver stomach was the presence of specific mucus with a thickness up to 950 µm (in frozen, unfixed sections that coated the mucosa. Our observations suggest that the formation of this mucus is complex and includes the secretory granule accumulation in the cytoplasm of pit cells, the granule aggregation inside cells, and the incorporation of degenerating cells into the mucus.

  2. Atomic force microscopy imaging reveals the formation of ASIC/ENaC cross-clade ion channels

    Energy Technology Data Exchange (ETDEWEB)

    Jeggle, Pia; Smith, Ewan St. J.; Stewart, Andrew P. [Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD (United Kingdom); Haerteis, Silke; Korbmacher, Christoph [Institut für Zelluläre und Molekulare Physiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Waldstrasse 6, 91054 Erlangen (Germany); Edwardson, J. Michael, E-mail: jme1000@cam.ac.uk [Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD (United Kingdom)

    2015-08-14

    ASIC and ENaC are co-expressed in various cell types, and there is evidence for a close association between them. Here, we used atomic force microscopy (AFM) to determine whether ASIC1a and ENaC subunits are able to form cross-clade hybrid ion channels. ASIC1a and ENaC could be co-isolated from detergent extracts of tsA 201 cells co-expressing the two subunits. Isolated proteins were incubated with antibodies against ENaC and Fab fragments against ASIC1a. AFM imaging revealed proteins that were decorated by both an antibody and a Fab fragment with an angle of ∼120° between them, indicating the formation of ASIC1a/ENaC heterotrimers. - Highlights: • There is evidence for a close association between ASIC and ENaC. • We used AFM to test whether ASIC1a and ENaC subunits form cross-clade ion channels. • Isolated proteins were incubated with subunit-specific antibodies and Fab fragments. • Some proteins were doubly decorated at ∼120° by an antibody and a Fab fragment. • Our results indicate the formation of ASIC1a/ENaC heterotrimers.

  3. Electron microscopy structure of human APC/C(CDH1)-EMI1 reveals multimodal mechanism of E3 ligase shutdown.

    Science.gov (United States)

    Frye, Jeremiah J; Brown, Nicholas G; Petzold, Georg; Watson, Edmond R; Grace, Christy R R; Nourse, Amanda; Jarvis, Marc A; Kriwacki, Richard W; Peters, Jan-Michael; Stark, Holger; Schulman, Brenda A

    2013-07-01

    The anaphase-promoting complex/cyclosome (APC/C) is a ~1.5-MDa multiprotein E3 ligase enzyme that regulates cell division by promoting timely ubiquitin-mediated proteolysis of key cell-cycle regulatory proteins. Inhibition of human APC/C(CDH1) during interphase by early mitotic inhibitor 1 (EMI1) is essential for accurate coordination of DNA synthesis and mitosis. Here, we report a hybrid structural approach involving NMR, electron microscopy and enzymology, which reveal that EMI1's 143-residue C-terminal domain inhibits multiple APC/C(CDH1) functions. The intrinsically disordered D-box, linker and tail elements, together with a structured zinc-binding domain, bind distinct regions of APC/C(CDH1) to synergistically both block the substrate-binding site and inhibit ubiquitin-chain elongation. The functional importance of intrinsic structural disorder is explained by enabling a small inhibitory domain to bind multiple sites to shut down various functions of a 'molecular machine' nearly 100 times its size.

  4. Enhanced electrostatic force microscopy reveals higher-order DNA looping mediated by the telomeric protein TRF2.

    Science.gov (United States)

    Kaur, Parminder; Wu, Dong; Lin, Jiangguo; Countryman, Preston; Bradford, Kira C; Erie, Dorothy A; Riehn, Robert; Opresko, Patricia L; Wang, Hong

    2016-02-09

    Shelterin protein TRF2 modulates telomere structures by promoting dsDNA compaction and T-loop formation. Advancement of our understanding of the mechanism underlying TRF2-mediated DNA compaction requires additional information regarding DNA paths in TRF2-DNA complexes. To uncover the location of DNA inside protein-DNA complexes, we recently developed the Dual-Resonance-frequency-Enhanced Electrostatic force Microscopy (DREEM) imaging technique. DREEM imaging shows that in contrast to chromatin with DNA wrapping around histones, large TRF2-DNA complexes (with volumes larger than TRF2 tetramers) compact DNA inside TRF2 with portions of folded DNA appearing at the edge of these complexes. Supporting coarse-grained molecular dynamics simulations uncover the structural requirement and sequential steps during TRF2-mediated DNA compaction and result in folded DNA structures with protruding DNA loops as seen in DREEM imaging. Revealing DNA paths in TRF2 complexes provides new mechanistic insights into structure-function relationships underlying telomere maintenance pathways.

  5. Differences in Nuclear DNA Organization Between Lymphocytes, Hodgkin and Reed–Sternberg Cells Revealed by Structured Illumination Microscopy

    NARCIS (Netherlands)

    Righolt, C.H.; Guffei, A.; Knecht, H.; Young, I.T.; Stallinga, S.; Van Vliet, L.J.; Mai, S.

    2014-01-01

    Advances in light microscopy have enabled the visualization of DNA in the interphase nucleus with more detail than is visible with conventional light microscopy. The nuclear architecture is assumed to be different in cancer cells compared to normal cells. In this paper we have studied, for the first

  6. Violence-related content in video game may lead to functional connectivity changes in brain networks as revealed by fMRI-ICA in young men.

    Science.gov (United States)

    Zvyagintsev, M; Klasen, M; Weber, R; Sarkheil, P; Esposito, F; Mathiak, K A; Schwenzer, M; Mathiak, K

    2016-04-21

    In violent video games, players engage in virtual aggressive behaviors. Exposure to virtual aggressive behavior induces short-term changes in players' behavior. In a previous study, a violence-related version of the racing game "Carmageddon TDR2000" increased aggressive affects, cognitions, and behaviors compared to its non-violence-related version. This study investigates the differences in neural network activity during the playing of both versions of the video game. Functional magnetic resonance imaging (fMRI) recorded ongoing brain activity of 18 young men playing the violence-related and the non-violence-related version of the video game Carmageddon. Image time series were decomposed into functional connectivity (FC) patterns using independent component analysis (ICA) and template-matching yielded a mapping to established functional brain networks. The FC patterns revealed a decrease in connectivity within 6 brain networks during the violence-related compared to the non-violence-related condition: three sensory-motor networks, the reward network, the default mode network (DMN), and the right-lateralized frontoparietal network. Playing violent racing games may change functional brain connectivity, in particular and even after controlling for event frequency, in the reward network and the DMN. These changes may underlie the short-term increase of aggressive affects, cognitions, and behaviors as observed after playing violent video games. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

  7. Magnetic domain structures and stray fields of individual elongated magnetite grains revealed by magnetic force microscopy (MFM)

    DEFF Research Database (Denmark)

    Frandsen, Cathrine; Stipp, S. L. S.; McEnroe, S. A.

    2004-01-01

    In order to clarify the relationship between microscopic and macroscopic magnetic features of a rock, we applied magnetic force microscopy (MFM) as a local probe on a sample with an intense natural remanent magnetisation, a norite from Heskestad, Norway. We studied in detail seven magnetite (Fe3O...

  8. Self-Assembled Framework Formed During Lithiation of SnS2 Nanoplates Revealed by in Situ Electron Microscopy.

    Science.gov (United States)

    Yin, Kuibo; Zhang, Minghao; Hood, Zachary D; Pan, Jie; Meng, Ying Shirley; Chi, Miaofang

    2017-07-18

    batteries, must be clearly understood. Probing these dynamic evolution processes, i.e. the lithiation reactions and morphology evolutions, are often challenging. It requires both high-resolution chemical analysis and microstructural identification. In situ transmission electron microscopy (TEM) coupled with electron energy loss spectroscopy (EELS) has recently been raised as one of the most powerful techniques for monitoring electrochemical processes in anode materials for LIBs. In this work, we focus on elucidating the origin of the structural stability of SnS2 during electrochemical cycling by revealing the microstructural evolution of SnS2 upon lithiation using in situ TEM. Crystalline SnS2 was observed to undergo a two-step reaction after the initial lithium intercalation: (1) irreversible formation of metallic tin and amorphous lithium sulfide and (2) reversible transformation of metallic tin to Li-Sn alloys, which is determined to be the rate-determining step. More interestingly, it was discovered that a self-assembled composite framework formed during the irreversible conversion reaction, which has not been previously reported. Crystalline Sn nanoparticles are well arranged within an amorphous Li2S "matrix" in this self-assembled framework. This nanoscale framework confines the locations of individual Sn nanoparticles and prevents particle agglomeration during the subsequent cycling processes, therefore providing desired structural tolerance and warranting a sufficientelectron pathway. Our results not only explain the outstanding cycling stability of SnS2 over metallic tin anodes, but also provide important mechanistic insights into the design of high-performance electrodes for next-generation LIBs through the integration of a unique nanoframework.

  9. Multimodal coherent anti-Stokes Raman scattering microscopy reveals microglia-associated myelin and axonal dysfunction in multiple sclerosis-like lesions in mice

    Science.gov (United States)

    Imitola, Jaime; Côté, Daniel; Rasmussen, Stine; Xie, X. Sunney; Liu, Yingru; Chitnis, Tanuja; Sidman, Richard L.; Lin, Charles. P.; Khoury, Samia J.

    2011-02-01

    Myelin loss and axonal degeneration predominate in many neurological disorders; however, methods to visualize them simultaneously in live tissue are unavailable. We describe a new imaging strategy combining video rate reflectance and fluorescence confocal imaging with coherent anti-Stokes Raman scattering (CARS) microscopy tuned to CH2 vibration of myelin lipids, applied in live tissue of animals with chronic experimental autoimmune encephalomyelitis (EAE). Our method allows monitoring over time of demyelination and neurodegeneration in brain slices with high spatial resolution and signal-to-noise ratio. Local areas of severe loss of lipid signal indicative of demyelination and loss of the reflectance signal from axons were seen in the corpus callosum and spinal cord of EAE animals. Even in myelinated areas of EAE mice, the intensity of myelin lipid signals is significantly reduced. Using heterozygous knock-in mice in which green fluorescent protein replaces the CX3CR1 coding sequence that labels central nervous system microglia, we find areas of activated microglia colocalized with areas of altered reflectance and CARS signals reflecting axonal injury and demyelination. Our data demonstrate the use of multimodal CARS microscopy for characterization of demyelinating and neurodegenerative pathology in a mouse model of multiple sclerosis, and further confirm the critical role of microglia in chronic inflammatory neurodegeneration.

  10. Differences in nuclear DNA organization between lymphocytes, Hodgkin and Reed-Sternberg cells revealed by structured illumination microscopy.

    Science.gov (United States)

    Righolt, Christiaan H; Guffei, Amanda; Knecht, Hans; Young, Ian T; Stallinga, Sjoerd; van Vliet, Lucas J; Mai, Sabine

    2014-08-01

    Advances in light microscopy have enabled the visualization of DNA in the interphase nucleus with more detail than is visible with conventional light microscopy. The nuclear architecture is assumed to be different in cancer cells compared to normal cells. In this paper we have studied, for the first time, the organization of nuclear DNA and that of DNA-free space in control lymphocytes, Hodgkin cells and Reed-Sternberg cells using 3D structured illumination microscopy (SIM). We have observed detail in these SIM images that was not observed in conventional widefield images. We have measured the size distribution of the DNA structure using granulometry and noted a significant, progressive increase in the amount of sub-micron structures from control lymphocytes to Hodgkin cells to Reed-Sternberg cells. The DNA-free space changes as well; "holes" in the DNA distribution start to appear in the malignant cells. We have studied whether these "holes" are nucleoli by staining for upstream binding factor (UBF), a protein associated with the nucleolus. We have found that the relative UBF content progressively and significantly decreases-or is absent-in the DNA-free space when measured as either the Pearson correlation coefficient with the DNA-free space or as the number of "holes" that contain UBF. Similar differences exist within the population of Reed-Sternberg cells between binucleated and multinucleated cells with four or more subnuclei. To our knowledge, this is the first study that investigates the changes of the nuclear DNA structure in any disease with superresolution light microscopy. © 2014 The Authors. Journal of Cellular Biochemistry published by Wiley Periodicals, Inc.

  11. Super-resolution microscopy reveals functional organization of dopamine transporters into cholesterol and neuronal activity-dependent nanodomains

    DEFF Research Database (Denmark)

    Rahbek-Clemmensen, Troels; Lycas, Matthew D.; Erlendsson, Simon

    2017-01-01

    to cholesterol depletion. Live photoactivated localization microscopy shows a similar dopamine transporter membrane organization in live heterologous cells. In neurons, dual-color dSTORM shows that tyrosine hydroxylase and vesicular monoamine transporter-2 are distinctively localized adjacent to......, but not overlapping with, the dopamine transporter nanodomains. The molecular organization of the dopamine transporter in nanodomains is reversibly reduced by short-term activation of NMDA-type ionotropic glutamate receptors, implicating dopamine transporter nanodomain distribution as a potential mechanism...

  12. Te inclusion-induced electrical field perturbation in CdZnTe single crystals revealed by Kelvin probe force microscopy.

    Science.gov (United States)

    Gu, Yaxu; Jie, Wanqi; Li, Linglong; Xu, Yadong; Yang, Yaodong; Ren, Jie; Zha, Gangqiang; Wang, Tao; Xu, Lingyan; He, Yihui; Xi, Shouzhi

    2016-09-01

    To understand the effects of tellurium (Te) inclusions on the device performance of CdZnTe radiation detectors, the perturbation of the electrical field in and around Te inclusions was studied in CdZnTe single crystals via Kelvin probe force microscopy (KPFM). Te inclusions were proved to act as lower potential centers with respect to surrounding CdZnTe matrix. Based on the KPFM results, the energy band diagram at the Te/CdZnTe interface was established, and the bias-dependent effects of Te inclusion on carrier transportation is discussed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Correlative Light-Electron Microscopy Reveals the Tubular-Saccular Ultrastructure of Carriers Operating between Golgi Apparatus and Plasma Membrane

    Science.gov (United States)

    Polishchuk, Roman S.; Polishchuk, Elena V.; Marra, Pierfrancesco; Alberti, Saverio; Buccione, Roberto; Luini, Alberto; Mironov, Alexander A.

    2000-01-01

    Transport intermediates (TIs) have a central role in intracellular traffic, and much effort has been directed towards defining their molecular organization. Unfortunately, major uncertainties remain regarding their true structure in living cells. To address this question, we have developed an approach based on the combination of the green fluorescent protein technology and correlative light-electron microscopy, by which it is possible to monitor an individual carrier in vivo and then take a picture of its ultrastructure at any moment of its lifecycle. We have applied this technique to define the structure of TIs operating from the Golgi apparatus to the plasma membrane, whose in vivo dynamics have been characterized recently by light microscopy. We find that these carriers are large (ranging from 0.3–1.7 μm in maximum diameter, nearly half the size of a Golgi cisterna), comprise almost exclusively tubular-saccular structures, and fuse directly with the plasma membrane, sometimes minutes after docking to the fusion site. PMID:10629217

  14. Semen analysis by electron and fluorescence microscopy in a case of partial hydatidiform mole reveals a high incidence of abnormal morphology, diploidy, and tetraploidy.

    Science.gov (United States)

    Chatzimeletiou, Katerina; Sioga, Antonia; Oikonomou, Louisa; Charalampidou, Sophia; Kantartzi, Persa; Zournatzi, Vasiliki; Panidis, Dimitrios; Goulis, Dimitrios G; Papadimas, Ioannis; Tarlatzis, Basil C

    2011-06-01

    To perform a highly detailed semen analysis in a man whose wife had a partial mole. Case report. Gynecology departments of two university hospitals and a laboratory of histology/embryology. A 32-year-old man whose wife had a partial mole. Sperm characteristics were examined by light microscopy, morphology was analysed by electron microscopy (TEM), DNA fragmentation was evaluated by TUNEL using fluorescence microscopy, and chromosomal abnormalities were assessed by fluorescence in situ hybridization using probes for chromosomes 13, 15, 16, 18, 21, 22, X, and Y. Sperm count, motility, morphology, DNA fragmentation, and incidence of diploidy, tetraploidy, and aneuploidy. Sperm concentration was 61 million/mL, with 31% progressive motility and 4% normal morphology. TEM revealed a high incidence of head, neck, and tail abnormalities as well as the presence of phagocytes. DNA fragmentation was within normal limits (11.6%). Aneuploidy levels were low for all chromosomes tested. However, there was a high level of diploidy, with XY, XX, and YY constitution. Tetraploid sperm (XXYY) were also noted. Semen analysis revealed a high incidence of abnormal morphology and increased diploidy. It may be important to perform FISH testing, to verify increased diploidy in sperm, in men whose wives have had partial moles. These couples could be informed of the option to have preimplantation genetic diagnosis as a means to distinguish between diploid and triploid embryos arising from fertilization of a haploid egg by diploid sperm. Copyright © 2011 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  15. Insight into the spin state at the surface of LaCoO3 revealed by photoemission electron microscopy

    Science.gov (United States)

    Yaroslavtsev, A. A.; Izquierdo, M.; Carley, R.; Dávila, M. E.; Ünal, A. A.; Kronast, F.; Lichtenstein, A.; Scherz, A.; Molodtsov, S. L.

    2016-04-01

    The evolution of the spin transition in LaCoO3 has been investigated with photoemission electron microscopy (PEEM) as a function of temperature. The investigated temperature range spanned from a predominantly low spin configuration (125 K) to the proposed percolation limit for metallization (413 K). The data show that the spin configuration exhibits an inhomogeneous spatial distribution that is very sensitive to the surface preparation method. In the region of the semiconductor-to-metal transition (300 to 450 K), the spatial contrast is continuously reduced, indicating a smooth transition without domain percolation. These observations support a new interpretation of the temperature evolution of the system that is in agreement with current theoretical understanding of the spin transition.

  16. Single-molecule super-resolution microscopy reveals how light couples to a plasmonic nanoantenna on the nanometer scale.

    Science.gov (United States)

    Wertz, Esther; Isaacoff, Benjamin P; Flynn, Jessica D; Biteen, Julie S

    2015-04-08

    The greatly enhanced fields near metal nanoparticles have demonstrated remarkable optical properties and are promising for applications from solar energy to biosensing. However, direct experimental study of these light-matter interactions at the nanoscale has remained difficult due to the limitations of optical microscopy. Here, we use single-molecule fluorescence imaging to probe how a plasmonic nanoantenna modifies the fluorescence emission from a dipole emitter. We show that the apparent fluorophore emission position is strongly shifted upon coupling to an antenna and that the emission of dyes located up to 90 nm away is affected by this coupling. To predict this long-ranged effect, we present a framework based on a distance-dependent partial coupling of the dye emission to the antenna. Our direct interpretation of these light-matter interactions will enable more predictably optimized, designed, and controlled plasmonic devices and will permit reliable plasmon-enhanced single-molecule nanoscopy.

  17. Atomic force microscopy-based microrheology reveals significant differences in the viscoelastic response between malign and benign cell lines.

    Science.gov (United States)

    Rother, Jan; Nöding, Helen; Mey, Ingo; Janshoff, Andreas

    2014-05-01

    Mechanical phenotyping of cells by atomic force microscopy (AFM) was proposed as a novel tool in cancer cell research as cancer cells undergo massive structural changes, comprising remodelling of the cytoskeleton and changes of their adhesive properties. In this work, we focused on the mechanical properties of human breast cell lines with different metastatic potential by AFM-based microrheology experiments. Using this technique, we are not only able to quantify the mechanical properties of living cells in the context of malignancy, but we also obtain a descriptor, namely the loss tangent, which provides model-independent information about the metastatic potential of the cell line. Including also other cell lines from different organs shows that the loss tangent (G″/G') increases generally with the metastatic potential from MCF-10A representing benign cells to highly malignant MDA-MB-231 cells.

  18. Scanning photocurrent microscopy reveals electron-hole asymmetry in ionic liquid-gated WS{sub 2} transistors

    Energy Technology Data Exchange (ETDEWEB)

    Ubrig, Nicolas, E-mail: nicolas.ubrig@unige.ch; Kuzmenko, Alexey B., E-mail: Alexey.Kuzmenko@unige.ch [DPMC, Université de Genève, 24 quai Ernest Ansermet, CH-1211 Geneva (Switzerland); Jo, Sanghyun; Morpurgo, Alberto F. [DPMC, Université de Genève, 24 quai Ernest Ansermet, CH-1211 Geneva (Switzerland); GAP, Université de Genève, 24 quai Ernest Ansermet, CH-1211 Geneva (Switzerland); Berger, Helmuth [Institut de Physique de la Matière Condendée, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne (Switzerland)

    2014-04-28

    We perform scanning photocurrent microscopy on WS{sub 2} ionic liquid-gated field effect transistors exhibiting high-quality ambipolar transport. By properly biasing the gate electrode, we can invert the sign of the photocurrent showing that the minority photocarriers are either electrons or holes. Both in the electron- and hole-doping regimes the photocurrent decays exponentially as a function of the distance between the illumination spot and the nearest contact, in agreement with a two-terminal Schottky-barrier device model. This allows us to compare the value and the doping dependence of the diffusion length of the minority electrons and holes on a same sample. Interestingly, the diffusion length of the minority carriers is several times larger in the hole accumulation regime than in the electron accumulation regime, pointing out an electron-hole asymmetry in WS{sub 2}.

  19. Scanning electron microscopy of stellate cells of mammalian adrenal cortex as revealed by NaOH maceration.

    Science.gov (United States)

    Martinotti, A; Macchiarelli, G; Finn, D W; Correr, S; Motta, P M

    1991-01-01

    After removal of connective tissues by the NaOH maceration method, adrenal gland stellate cells of monkeys, rats and rabbits were studied by scanning electron microscopy. The stellate cells were situated in the perivascular and interstitial spaces and showed an ovoid cell body with numerous round or flat processes. Through these processes they were in contact with other adjacent stellate cells and thus formed a continuous cellular net around capillaries and parenchymal cells. This net, which probably provides a cellular scaffolding for the gland, may also play additional roles such as capillary contraction and nutrition for adjacent parenchymal cells. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 PMID:1817138

  20. X-ray fluorescence microscopy reveals accumulation and secretion of discrete intracellular zinc pools in the lactating mouse mammary gland.

    Directory of Open Access Journals (Sweden)

    Nicholas McCormick

    2010-06-01

    Full Text Available The mammary gland is responsible for the transfer of a tremendous amount of zinc ( approximately 1-3 mg zinc/day from maternal circulation into milk during lactation to support the growth and development of the offspring. When this process is compromised, severe zinc deficiency compromises neuronal development and immune function and increases infant morbidity and/or mortality. It remains unclear as to how the lactating mammary gland dynamically integrates zinc import from maternal circulation with the enormous amount of zinc that is secreted into milk.Herein we utilized X-ray fluorescence microscopy (XFM which allowed for the visualization and quantification of the process of zinc transfer through the mammary gland of the lactating mouse. Our data illustrate that a large amount of zinc first accumulates in the mammary gland during lactation. Interestingly, this zinc is not cytosolic, but accumulated in large, discrete sub-cellular compartments. These zinc pools were then redistributed to small intracellular vesicles destined for secretion in a prolactin-responsive manner. Confocal microscopy identified mitochondria and the Golgi apparatus as the sub-cellular compartments which accumulate zinc; however, zinc pools in the Golgi apparatus, but not mitochondria are redistributed to vesicles destined for secretion during lactation.Our data directly implicate the Golgi apparatus in providing a large, mobilizable zinc storage pool to assist in providing for the tremendous amount of zinc that is secreted into milk. Interestingly, our study also provides compelling evidence that mitochondrial zinc pools expand in the mammary gland during lactation which we speculate may play a role in regulating mammary gland function.

  1. Surface and flagella morphology of the motile form of Chromera velia revealed by field-emission scanning electron microscopy.

    Science.gov (United States)

    Weatherby, Kate; Murray, Shauna; Carter, Dee; Slapeta, Jan

    2011-01-01

    Chromera velia(Chromerida; Alveolata) is an autotrophic protist isolated from stony corals.Ch. veliapossesses a chloroplast thought to be most closely related to the apicoplasts of non-photosynthetic apicomplexa. Phylogenetic analyses placeCh. veliaas a close relative of parasitic apicomplexa and predatory colpodellids. We have used field-emission scanning electron microscopy of cells sputter-coated with gold or chromium and non-coated cells to characterise the surface ultrastructure of the motile form ofCh. velia. In overall morphology the biflagellatedCh. veliacells resemble the colpodellidColpodella edax, but with some notable differences. The ventral side of the flagellatedCh. veliacell has two grooves extending from the anterior flagella insertion point with a ridge rising towards the anterior apex of the cell. The anterior flagellum is shorter than the posterior flagellum and possesses a distinct, small curved appendage. The insertion point of the anterior flagellum is partly enclosed by a flap extending from the cell. The posterior flagellum is approximately four times the length of the cell and possesses mastigonemes. The combination of coating techniques proved superior to the commonly used gold coating to determine fine surface ultrastructure. This new ultrastructural information forCh. veliaallowed us to emend its diagnosis. 2010 Elsevier GmbH. All rights reserved.

  2. Ultrastructure of the innermost surface of differentiating normal and compression wood tracheids as revealed by field emission scanning electron microscopy.

    Science.gov (United States)

    Kim, Jong Sik; Awano, Tatsuya; Yoshinaga, Arata; Takabe, Keiji

    2012-06-01

    The ultrastructure of the innermost surface of Cryptomeria japonica differentiating normal wood (NW) and compression wood (CW) was comparatively investigated by field emission electron microscopy (FE-SEM) combined with enzymatic degradation of hemicelluloses. Cellulose microfibril (CMF) bundles were readily observed in NW tracheids in the early stage of secondary cell wall formation, but not in CW tracheids because of the heavy accumulation of amorphous materials composed mainly of galactans and lignin. This result suggests that the ultrastructural deposition of cell wall components in the tracheid cell wall differ between NW and CW from the early stage of secondary cell wall formation. Delignified NW and CW tracheids showed similar structural changes during differentiating stages after xylanase or β-mannanase treatment, whereas they exhibited clear differences in ultrastructure in mature stages. Although thin CMF bundles were exposed in both delignified mature NW and CW tracheids by xylanase treatment, ultrastructural changes following β-mannanase treatment were only observed in CW tracheids. CW tracheids also showed different degradation patterns between xylanase and β-mannanase. CMF bundles showed a smooth surface in delignified mature CW tracheids treated with xylanase, whereas they had an uneven surface in delignified mature CW tracheids treated with β-mannanase, indicating that the uneven surface of CMF bundles was related to xylans. The present results suggest that ultrastructural deposition and organization of lignin and hemicelluloses in CW tracheids may differ from those of NW tracheids.

  3. Inter- and intraspecific structural variations among intervascular pit membranes, as revealed by field-emission scanning electron microscopy.

    Science.gov (United States)

    Sano, Yuzou

    2005-07-01

    The structure of the intervascular pit membranes of four dicotyledonous species (Salix sachalinensis, Betula platyphylla var. japonica, Acer mono, and Fraxinus mandshurica var. japonica) was examined by field-emission scanning electron microscopy. The intervascular pit membranes of F. mandshurica var. japonica had thin surface layers and a dense middle layer, while no similar middle layer was detectable in the other three species. In F. mandshurica var. japonica, the entire area of each pit membrane was densely covered with microfibrils. In the other three species, by contrast, openings were found in the pit membranes. In some of the intervascular pit membranes of S. sachalinensis, B. platyphylla var. japonica, and A. mono, microfibrils were sparsely interwoven in small areas of the pit membranes and openings of up to several hundred nanometers in diameter were present in such regions. These porous regions tended to be located in peripheral areas of pit membranes. In S. sachalinensis and B. platyphylla var. japonica, ethanol-soluble extracts, whose chemical nature and function remain unknown, were heavily distributed over the intervascular pit membranes. Our observations suggest that the structure of intervascular pit membranes is more complicated than has previously been acknowledged.

  4. Single-Molecule Fluorescence Microscopy Reveals Local Diffusion Coefficients in the Pore Network of an Individual Catalyst Particle.

    Science.gov (United States)

    Hendriks, Frank C; Meirer, Florian; Kubarev, Alexey V; Ristanović, Zoran; Roeffaers, Maarten B J; Vogt, Eelco T C; Bruijnincx, Pieter C A; Weckhuysen, Bert M

    2017-10-04

    We used single-molecule fluorescence microscopy to study self-diffusion of a feedstock-like probe molecule with nanometer accuracy in the macropores of a micrometer-sized, real-life fluid catalytic cracking (FCC) particle. Movies of single fluorescent molecules allowed their movement through the pore network to be reconstructed. The observed tracks were classified into three different states by machine learning and all found to be distributed homogeneously over the particle. Most probe molecules (88%) were immobile, with the molecule most likely being physisorbed or trapped; the remainder was either mobile (8%), with the molecule moving inside the macropores, or showed hybrid behavior (4%). Mobile tracks had an average diffusion coefficient of D = 8 × 10-14 ± 1 × 10-13 m2 s-1, with the standard deviation thought to be related to the large range of pore sizes found in FCC particles. The developed methodology can be used to evaluate, quantify and map heterogeneities in diffusional properties within complex hierarchically porous materials.

  5. Phasor fluorescence lifetime microscopy of free and protein-bound NADH reveals neural stem cell differentiation potential.

    Directory of Open Access Journals (Sweden)

    Chiara Stringari

    Full Text Available In the stem cell field there is a lack of non invasive and fast methods to identify stem cell's metabolic state, differentiation state and cell-lineage commitment. Here we describe a label-free method that uses NADH as an intrinsic biomarker and the Phasor approach to Fluorescence Lifetime microscopy to measure the metabolic fingerprint of cells. We show that different metabolic states are related to different cell differentiation stages and to stem cell bias to neuronal and glial fate, prior the expression of lineage markers. Our data demonstrate that the NADH FLIM signature distinguishes non-invasively neurons from undifferentiated neural progenitor and stem cells (NPSCs at two different developmental stages (E12 and E16. NPSCs follow a metabolic trajectory from a glycolytic phenotype to an oxidative phosphorylation phenotype through different stages of differentiation. NSPCs are characterized by high free/bound NADH ratio, while differentiated neurons are characterized by low free/bound NADH ratio. We demonstrate that the metabolic signature of NPSCs correlates with their differentiation potential, showing that neuronal progenitors and glial progenitors have a different free/bound NADH ratio. Reducing conditions in NPSCs correlates with their neurogenic potential, while oxidative conditions correlate with glial potential. For the first time we show that FLIM NADH metabolic fingerprint provides a novel, and quantitative measure of stem cell potential and a label-free and non-invasive means to identify neuron- or glial- biased progenitors.

  6. Quantitative FLIM-FRET Microscopy to Monitor Nanoscale Chromatin Compaction In Vivo Reveals Structural Roles of Condensin Complexes.

    Science.gov (United States)

    Llères, David; Bailly, Aymeric P; Perrin, Aurélien; Norman, David G; Xirodimas, Dimitris P; Feil, Robert

    2017-02-14

    How metazoan genomes are structured at the nanoscale in living cells and tissues remains unknown. Here, we adapted a quantitative FRET (Förster resonance energy transfer)-based fluorescence lifetime imaging microscopy (FLIM) approach to assay nanoscale chromatin compaction in living organisms. Caenorhabditis elegans was chosen as a model system. By measuring FRET between histone-tagged fluorescent proteins, we visualized distinct chromosomal regions and quantified the different levels of nanoscale compaction in meiotic cells. Using RNAi and repetitive extrachromosomal array approaches, we defined the heterochromatin state and showed that its architecture presents a nanoscale-compacted organization controlled by Heterochromatin Protein-1 (HP1) and SETDB1 H3-lysine-9 methyltransferase homologs in vivo. Next, we functionally explored condensin complexes. We found that condensin I and condensin II are essential for heterochromatin compaction and that condensin I additionally controls lowly compacted regions. Our data show that, in living animals, nanoscale chromatin compaction is controlled not only by histone modifiers and readers but also by condensin complexes. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  7. Inorganic WS{sub 2} nanotubes revealed atom by atom using ultra-high-resolution transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Bar Sadan, Maya; Heidelmann, Markus; Houben, Lothar [Forschungszentrum Juelich GmbH, Institute of Solid State Research and Ernst Ruska Centre for Microscopy and Spectroscopy with Electrons, Juelich (Germany); Tenne, Reshef [Weizmann Institute of Science, Materials and Interfaces Department, Rehovot (Israel)

    2009-08-15

    The characterization of nanostructures to the atomic dimensions becomes more important, as devices based on a single particle are being produced. In particular, inorganic nanotubes were shown to host interesting properties making them excellent candidates for various devices. The WS{sub 2} nanotubes outperform the bulk in their mechanical properties offering numerous applications especially as part of high strength nanocomposites. In contrast, their electrical properties are less remarkable. The structure-function relationship can be investigated by aberration-corrected high-resolution transmission electron microscopy (HRTEM), which enables the insight into their atomic structure as well as performing spectroscopic measurements down to the atomic scale. In the present work, the deciphering of atomic structure and the chiral angle of the different shells in a multiwall WS{sub 2} nanotube is demonstrated. In certain cases, the helicity of the structure can also be deduced. Finally, first electron energy loss spectra (EELS) of a single tube are presented, acquired by a new acquisition technique that allows for high spatial resolution (denoted StripeSTEM). The measured band gap values correspond with the values found in literature for thin films, obtained by spectroscopic techniques, and are higher than the values resulting from STM measurements. (orig.)

  8. Structural features of the salivary gland hypertrophy virus of the tsetse fly revealed by cryo-electron microscopy and tomography.

    Science.gov (United States)

    Orlov, Igor; Drillien, Robert; Spehner, Danièle; Bergoin, Max; Abd-Alla, Adly M M; Klaholz, Bruno P

    2017-11-27

    Glossina palipides salivary gland hypertrophy virus (GpSGHV) infects tsetse flies, which are vectors for African trypanosomosis. This virus represents a major challenge in insect mass rearing and has hampered the implementation of the sterile insect technique programs in the Member States of the International Atomic Energy Agency. GpSGHV virions consist of long rod-shaped particles over 9000Å in length, but little is known about their detailed structural organization. We show by cryo electron microscopy and cryo electron tomography that the GpSGHV virion has a unique, non-icosahedral helical structure. Its envelope exhibits regularly spaced spikes that protrude from the lipid bilayer and are arranged on a four-start helix. This study provides a detailed insight into the 3D architecture of GpSGHV, which will help to understand the viral life cycle and possibly allow the design of antiviral strategies in the context of tsetse fly infections. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. The architecture of amyloid-like peptide fibrils revealed by X-ray scattering, diffraction and electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Langkilde, Annette E., E-mail: annette.langkilde@sund.ku.dk [University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen (Denmark); Morris, Kyle L.; Serpell, Louise C. [University of Sussex, Falmer, Brighton (United Kingdom); Svergun, Dmitri I. [European Molecular Biology Laboratory, Hamburg Outstation, 22607 Hamburg (Germany); Vestergaard, Bente [University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen (Denmark)

    2015-04-01

    The aggregation process and the fibril state of an amyloidogenic peptide suggest monomer addition to be the prevailing mechanism of elongation and a model of the peptide packing in the fibrils has been obtained. Structural analysis of protein fibrillation is inherently challenging. Given the crucial role of fibrils in amyloid diseases, method advancement is urgently needed. A hybrid modelling approach is presented enabling detailed analysis of a highly ordered and hierarchically organized fibril of the GNNQQNY peptide fragment of a yeast prion protein. Data from small-angle X-ray solution scattering, fibre diffraction and electron microscopy are combined with existing high-resolution X-ray crystallographic structures to investigate the fibrillation process and the hierarchical fibril structure of the peptide fragment. The elongation of these fibrils proceeds without the accumulation of any detectable amount of intermediate oligomeric species, as is otherwise reported for, for example, glucagon, insulin and α-synuclein. Ribbons constituted of linearly arranged protofilaments are formed. An additional hierarchical layer is generated via the pairing of ribbons during fibril maturation. Based on the complementary data, a quasi-atomic resolution model of the protofilament peptide arrangement is suggested. The peptide structure appears in a β-sheet arrangement reminiscent of the β-zipper structures evident from high-resolution crystal structures, with specific differences in the relative peptide orientation. The complexity of protein fibrillation and structure emphasizes the need to use multiple complementary methods.

  10. Quantitative FLIM-FRET Microscopy to Monitor Nanoscale Chromatin Compaction In Vivo Reveals Structural Roles of Condensin Complexes

    Directory of Open Access Journals (Sweden)

    David Llères

    2017-02-01

    Full Text Available How metazoan genomes are structured at the nanoscale in living cells and tissues remains unknown. Here, we adapted a quantitative FRET (Förster resonance energy transfer-based fluorescence lifetime imaging microscopy (FLIM approach to assay nanoscale chromatin compaction in living organisms. Caenorhabditis elegans was chosen as a model system. By measuring FRET between histone-tagged fluorescent proteins, we visualized distinct chromosomal regions and quantified the different levels of nanoscale compaction in meiotic cells. Using RNAi and repetitive extrachromosomal array approaches, we defined the heterochromatin state and showed that its architecture presents a nanoscale-compacted organization controlled by Heterochromatin Protein-1 (HP1 and SETDB1 H3-lysine-9 methyltransferase homologs in vivo. Next, we functionally explored condensin complexes. We found that condensin I and condensin II are essential for heterochromatin compaction and that condensin I additionally controls lowly compacted regions. Our data show that, in living animals, nanoscale chromatin compaction is controlled not only by histone modifiers and readers but also by condensin complexes.

  11. High resolution microscopy reveals significant impacts of ocean acidification and warming on larval shell development in Laternula elliptica.

    Directory of Open Access Journals (Sweden)

    Christine H Bylenga

    Full Text Available Environmental stressors impact marine larval growth rates, quality and sizes. Larvae of the Antarctic bivalve, Laternula elliptica, were raised to the D-larvae stage under temperature and pH conditions representing ambient and end of century projections (-1.6°C to +0.4°C and pH 7.98 to 7.65. Previous observations using light microscopy suggested pH had no influence on larval abnormalities in this species. Detailed analysis of the shell using SEM showed that reduced pH is in fact a major stressor during development for this species, producing D-larvae with abnormal shapes, deformed shell edges and irregular hinges, cracked shell surfaces and even uncalcified larvae. Additionally, reduced pH increased pitting and cracking on shell surfaces. Thus, apparently normal larvae may be compromised at the ultrastructural level and these larvae would be in poor condition at settlement, reducing juvenile recruitment and overall survival. Elevated temperatures increased prodissoconch II sizes. However, the overall impacts on larval shell quality and integrity with concurrent ocean acidification would likely overshadow any beneficial results from warmer temperatures, limiting populations of this prevalent Antarctic species.

  12. High-Speed Atomic Force Microscopy Reveals the Inner Workings of the MinDE Protein Oscillator.

    Science.gov (United States)

    Miyagi, Atsushi; Ramm, Beatrice; Schwille, Petra; Scheuring, Simon

    2018-01-10

    The MinDE protein system from E. coli has recently been identified as a minimal biological oscillator, based on two proteins only: The ATPase MinD and the ATPase activating protein MinE. In E. coli, the system works as the molecular ruler to place the divisome at midcell for cell division. Despite its compositional simplicity, the molecular mechanism leading to protein patterns and oscillations is still insufficiently understood. Here we used high-speed atomic force microscopy to analyze the mechanism of MinDE membrane association/dissociation dynamics on isolated membrane patches, down to the level of individual point oscillators. This nanoscale analysis shows that MinD association to and dissociation from the membrane are both highly cooperative but mechanistically different processes. We propose that they represent the two directions of a single allosteric switch leading to MinD filament formation and depolymerization. Association/dissociation are separated by rather long apparently silent periods. The membrane-associated period is characterized by MinD filament multivalent binding, avidity, while the dissociated period is defined by seeding of individual MinD. Analyzing association/dissociation kinetics with varying MinD and MinE concentrations and dependent on membrane patch size allowed us to disentangle the essential dynamic variables of the MinDE oscillation cycle.

  13. High resolution microscopy reveals significant impacts of ocean acidification and warming on larval shell development in Laternula elliptica

    Science.gov (United States)

    Cummings, Vonda J.; Ryan, Ken G.

    2017-01-01

    Environmental stressors impact marine larval growth rates, quality and sizes. Larvae of the Antarctic bivalve, Laternula elliptica, were raised to the D-larvae stage under temperature and pH conditions representing ambient and end of century projections (-1.6°C to +0.4°C and pH 7.98 to 7.65). Previous observations using light microscopy suggested pH had no influence on larval abnormalities in this species. Detailed analysis of the shell using SEM showed that reduced pH is in fact a major stressor during development for this species, producing D-larvae with abnormal shapes, deformed shell edges and irregular hinges, cracked shell surfaces and even uncalcified larvae. Additionally, reduced pH increased pitting and cracking on shell surfaces. Thus, apparently normal larvae may be compromised at the ultrastructural level and these larvae would be in poor condition at settlement, reducing juvenile recruitment and overall survival. Elevated temperatures increased prodissoconch II sizes. However, the overall impacts on larval shell quality and integrity with concurrent ocean acidification would likely overshadow any beneficial results from warmer temperatures, limiting populations of this prevalent Antarctic species. PMID:28423059

  14. Exceptionally preserved Cambrian trilobite digestive system revealed in 3D by synchrotron-radiation X-ray tomographic microscopy.

    Directory of Open Access Journals (Sweden)

    Mats E Eriksson

    Full Text Available The Cambrian 'Orsten' fauna comprises exceptionally preserved and phosphatised microscopic arthropods. The external morphology of these fossils is well known, but their internal soft-tissue anatomy has remained virtually unknown. Here, we report the first non-biomineralised tissues from a juvenile polymerid trilobite, represented by digestive structures, glands, and connective strands harboured in a hypostome from the Swedish 'Orsten' fauna. Synchrotron-radiation X-ray tomographic microscopy enabled three-dimensional internal recordings at sub-micrometre resolution. The specimen provides the first unambiguous evidence for a J-shaped anterior gut and the presence of a crop with a constricted alimentary tract in the Trilobita. Moreover, the gut is Y-shaped in cross section, probably due to a collapsed lumen of that shape, another feature which has not previously been observed in trilobites. The combination of anatomical features suggests that the trilobite hypostome is functionally analogous to the labrum of euarthropods and that it was a sophisticated element closely integrated with the digestive system. This study also briefly addresses the preservational bias of the 'Orsten' fauna, particularly the near-absence of polymerid trilobites, and the taphonomy of the soft-tissue-harbouring hypostome.

  15. L-type Ca2+ channel sparklets revealed by TIRF microscopy in mouse urinary bladder smooth muscle.

    Science.gov (United States)

    Sidaway, Peter; Teramoto, Noriyoshi

    2014-01-01

    Calcium is a ubiquitous second messenger in urinary bladder smooth muscle (UBSM). In this study, small discrete elevations of intracellular Ca(2+), referred to as Ca(2+) sparklets have been detected in an intact detrusor smooth muscle electrical syncytium using a TIRF microscopy Ca(2+) imaging approach. Sparklets were virtually abolished by the removal of extracellular Ca(2+) (0.035 ± 0.01 vs. 0.23 ± 0.07 Hz/mm(2); P0.05), implying that Ca(2+) store mediated signals regulate Ca(2+) sparklets. Under control conditions, inhibition of store operated Ca(2+) entry using ML-9 (100 μM) had no significant effect. Amplitudes of Ca(2+) sparklets were unaffected by any agonists or antagonists, suggesting that these signals are quantal events arising from activation of a single channel, or complex of channels. The effects of CPA and ML-9 suggest that Ca(2+) sparklets regulate events in the cell membrane, and contribute to cytosolic and sarcoplasmic Ca(2+) concentrations.

  16. L-type Ca2+ channel sparklets revealed by TIRF microscopy in mouse urinary bladder smooth muscle.

    Directory of Open Access Journals (Sweden)

    Peter Sidaway

    Full Text Available Calcium is a ubiquitous second messenger in urinary bladder smooth muscle (UBSM. In this study, small discrete elevations of intracellular Ca(2+, referred to as Ca(2+ sparklets have been detected in an intact detrusor smooth muscle electrical syncytium using a TIRF microscopy Ca(2+ imaging approach. Sparklets were virtually abolished by the removal of extracellular Ca(2+ (0.035 ± 0.01 vs. 0.23 ± 0.07 Hz/mm(2; P0.05, implying that Ca(2+ store mediated signals regulate Ca(2+ sparklets. Under control conditions, inhibition of store operated Ca(2+ entry using ML-9 (100 μM had no significant effect. Amplitudes of Ca(2+ sparklets were unaffected by any agonists or antagonists, suggesting that these signals are quantal events arising from activation of a single channel, or complex of channels. The effects of CPA and ML-9 suggest that Ca(2+ sparklets regulate events in the cell membrane, and contribute to cytosolic and sarcoplasmic Ca(2+ concentrations.

  17. Atomic Force Microscopy Reveals a Role for Endothelial Cell ICAM-1 Expression in Bladder Cancer Cell Adherence

    Science.gov (United States)

    Laurent, Valérie M.; Duperray, Alain; Sundar Rajan, Vinoth; Verdier, Claude

    2014-01-01

    Cancer metastasis is a complex process involving cell-cell interactions mediated by cell adhesive molecules. In this study we determine the adhesion strength between an endothelial cell monolayer and tumor cells of different metastatic potentials using Atomic Force Microscopy. We show that the rupture forces of receptor-ligand bonds increase with retraction speed and range between 20 and 70 pN. It is shown that the most invasive cell lines (T24, J82) form the strongest bonds with endothelial cells. Using ICAM-1 coated substrates and a monoclonal antibody specific for ICAM-1, we demonstrate that ICAM-1 serves as a key receptor on endothelial cells and that its interactions with ligands expressed by tumor cells are correlated with the rupture forces obtained with the most invasive cancer cells (T24, J82). For the less invasive cancer cells (RT112), endothelial ICAM-1 does not seem to play any role in the adhesion process. Moreover, a detailed analysis of the distribution of rupture forces suggests that ICAM-1 interacts preferentially with one ligand on T24 cancer cells and with two ligands on J82 cancer cells. Possible counter receptors for these interactions are CD43 and MUC1, two known ligands for ICAM-1 which are expressed by these cancer cells. PMID:24857933

  18. Spatial Distributions of Discharged Products of Lithium-Oxygen Batteries Revealed by Synchrotron X-ray Transmission Microscopy.

    Science.gov (United States)

    Olivares-Marín, Mara; Sorrentino, Andrea; Lee, Rung-Chuan; Pereiro, Eva; Wu, Nae-Lih; Tonti, Dino

    2015-10-14

    The discharge products of ether-based Li-O2 cells were grown directly on common carbon-coated TEM grids and observed by oxidation-state-sensitive full field transmission soft X-ray microscopy (TXM). The acquired data have permitted to quantify and localize with spatial resolution the distribution of the oxygen discharge products in these samples (i.e., lithium superoxide, peroxide, and carbonates) and appreciate several compositional, structural, and morphological aspects. Most of the peroxide particles had a toroidal shape, often with a central hole usually open on only one side, and which included significant amounts of superoxide-like phases (LiO2/Li2O2 ratio between 0.2 and 0.5). Smaller particles had smaller or no superoxide content, from which we infer that abundance of soluble LiO2 may have a role in toroid formation. Significant amount of carbonates were found irregularly distributed on the electrode surface, occasionally appearing as small particles and aggregates, and mostly coating lithium peroxide particles. This suggests the formation of a barrier that, similar to the solid electrolyte interface (SEI) critical in Li-ion batteries, requires an appropriate management for a reversible operation.

  19. Evolution and Function of Dinosaur Teeth at Ultramicrostructural Level Revealed Using Synchrotron Transmission X-ray Microscopy.

    Science.gov (United States)

    Wang, Chun-Chieh; Song, Yen-Fang; Song, Sheng-Rong; Ji, Qiang; Chiang, Cheng-Cheng; Meng, Qingjin; Li, Haibing; Hsiao, Kiko; Lu, Yi-Chia; Shew, Bor-Yuan; Huang, Timothy; Reisz, Robert R

    2015-10-29

    The relationship between tooth form and dietary preference is a crucial issue in vertebrate evolution. However, the mechanical properties of a tooth are influenced not only by its shape but also by its internal structure. Here, we use synchrotron transmission X-ray microscopy to examine the internal microstructures of multiple dinosaur teeth within a phylogenetic framework. We found that the internal microstructures of saurischian teeth are very different from advanced ornithischian teeth, reflecting differences in dental developmental strategies. The three-tissue composition (enamel-mantle dentin-bulk dentin) near the dentinoenamel junction (DEJ) in saurischian teeth represents the primitive condition of dinosaur teeth. Mantle dentin, greatly reduced or absent from DEJ in derived ornithischian teeth, is a key difference between Saurischia and Ornithischia. This may be related to the derived herbivorous feeding behavior of ornithischians, but interestingly, it is still retained in the herbivorous saurischian sauropods. The protective functions of mantle dentin with porous microstructures between enamel and bulk dentin inside typical saurischian teeth are also discussed using finite-element analysis method. Evolution of the dental modifications in ornithischian dinosaurs, with the absence of mantle dentin, may be related to changes in enamel characteristics with enamel spindles extending through the DEJ.

  20. High-Speed Atomic Force Microscopy Reveals Loss of Nuclear Pore Resilience as a Dying Code in Colorectal Cancer Cells.

    Science.gov (United States)

    Mohamed, Mahmoud Shaaban; Kobayashi, Akiko; Taoka, Azuma; Watanabe-Nakayama, Takahiro; Kikuchi, Yosuke; Hazawa, Masaharu; Minamoto, Toshinari; Fukumori, Yoshihiro; Kodera, Noriyuki; Uchihashi, Takayuki; Ando, Toshio; Wong, Richard W

    2017-06-27

    Nuclear pore complexes (NPCs) are the sole turnstile implanted in the nuclear envelope (NE), acting as a central nanoregulator of transport between the cytosol and the nucleus. NPCs consist of ∼30 proteins, termed nucleoporins. About one-third of nucleoporins harbor natively unstructured, intrinsically disordered phenylalanine-glycine strings (FG-Nups), which engage in transport selectivity. Because the barriers insert deeply in the NPC, they are nearly inaccessible. Several in vitro barrier models have been proposed; however, the dynamic FG-Nups protein molecules themselves are imperceptible in vivo. We show here that high-speed atomic force microscopy (HS-AFM) can be used to directly visualize nanotopographical changes of the nuclear pore inner channel in colorectal cancer (CRC) cells. Furthermore, using MLN8237/alisertib, an apoptotic and autophagic inducer currently being tested in relapsed cancer clinical trials, we unveiled the functional loss of nucleoporins, particularly the deformation of the FG-Nups barrier, in dying cancer cells. We propose that the loss of this nanoscopic resilience is an irreversible dying code in cells. These findings not only illuminate the potential application of HS-AFM as an intracellular nanoendoscopy but also might aid in the design of future nuclear targeted nanodrug delivery tailored to the individual patient.

  1. Vertical zonation and functional diversity of fish assemblages revealed by ROV videos at oil platforms in The Gulf.

    Science.gov (United States)

    Torquato, F; Jensen, H M; Range, P; Bach, S S; Ben-Hamadou, R; Sigsgaard, E E; Thomsen, P F; Møller, P R; Riera, R

    2017-09-01

    An assessment of vertical distribution, diel migration, taxonomic and functional diversity of fishes was carried out at offshore platforms in The (Arabian-Iranian-Persian) Gulf. Video footage was recorded at the Al Shaheen oil field between 2007 and 2014 using a remotely operated vehicle (ROV). A total of 12 822 individual fishes, from 83 taxonomic groups were recorded around the platforms. All the species identified are considered native to The Gulf, although Cyclichthys orbicularis and Lutjanus indicus were recorded for the first time in Qatari waters. Several trends were uncovered in the vertical distribution of the fish community; most species were observed between 20 and 50 m depth and fish abundance decreased towards the bottom, with the highest abundances recorded in the upper layers, i.e. down to 40 m depth. Vertical variation in fish diversity, however, was generally not accompanied by differences in vertical movements. Carnivores and invertivores were the dominant trophic groups, being found at each depth range from surface to seabed. The functional indices showed no significant differences between water depths or diel cycles. The study demonstrates that oil platforms represent a hotspot of fish diversity and interesting sites for studying fish communities, abundance and behaviour. © 2017 The Fisheries Society of the British Isles.

  2. High-speed video gait analysis reveals early and characteristic locomotor phenotypes in mouse models of neurodegenerative movement disorders.

    Science.gov (United States)

    Preisig, Daniel F; Kulic, Luka; Krüger, Maik; Wirth, Fabian; McAfoose, Jordan; Späni, Claudia; Gantenbein, Pascal; Derungs, Rebecca; Nitsch, Roger M; Welt, Tobias

    2016-09-15

    Neurodegenerative diseases of the central nervous system frequently affect the locomotor system resulting in impaired movement and gait. In this study we performed a whole-body high-speed video gait analysis in three different mouse lines of neurodegenerative movement disorders to investigate the motor phenotype. Based on precise computerized motion tracking of all relevant joints and the tail, a custom-developed algorithm generated individual and comprehensive locomotor profiles consisting of 164 spatial and temporal parameters. Gait changes observed in the three models corresponded closely to the classical clinical symptoms described in these disorders: Muscle atrophy due to motor neuron loss in SOD1 G93A transgenic mice led to gait characterized by changes in hind-limb movement and positioning. In contrast, locomotion in huntingtin N171-82Q mice modeling Huntington's disease with basal ganglia damage was defined by hyperkinetic limb movements and rigidity of the trunk. Harlequin mutant mice modeling cerebellar degeneration showed gait instability and extensive changes in limb positioning. Moreover, model specific gait parameters were identified and were shown to be more sensitive than conventional motor tests. Altogether, this technique provides new opportunities to decipher underlying disease mechanisms and test novel therapeutic approaches. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Musculature of Notholca acuminata (Rotifera: Ploima: Brachionidae) revealed by confocal scanning laser microscopy

    DEFF Research Database (Denmark)

    Sørensen, M.V.; Funch, P.; Hooge, M.

    2003-01-01

    , stomach, gut, and cloaca, including thin longitudinal gut fibers and viscero-cloacal fibers, never before reported in other species of rotifers. The dorsal, lateral, and ventral retractor muscles and the incomplete circular muscles associated with the body wall appear to be apomorphies for the Rotifera....... Muscle-revealing staining shows promise for providing additional information on previously unrecognized complexity in rotifer musculature that will be useful in functional morphology and phylogenetic analyses...

  4. Musculature of Notholca acuminata (Rotifera : Ploima : Brachionidae) revealed by confocal scanning laser microscopy

    DEFF Research Database (Denmark)

    Sørensen, M.V.; Funch, P.; Hooge, M.

    2003-01-01

    , stomach, gut, and cloaca, including thin longitudinal gut fibers and viscero-cloacal fibers, never before reported in other species of rotifers. The dorsal, lateral, and ventral retractor muscles and the incomplete circular muscles associated with the body wall appear to be apomorphies for the Rotifera....... Muscle-revealing staining shows promise for providing additional information on previously unrecognized complexity in rotifer musculature that will be useful in functional morphology and phylogenetic analyses...

  5. Phase Boundary Propagation in Li-Alloying Battery Electrodes Revealed by Liquid-Cell Transmission Electron Microscopy.

    Science.gov (United States)

    Leenheer, Andrew J; Jungjohann, Katherine L; Zavadil, Kevin R; Harris, Charles T

    2016-06-28

    Battery cycle life is directly influenced by the microstructural changes occurring in the electrodes during charge and discharge cycles. Here, we image in situ the nanoscale phase evolution in negative electrode materials for Li-ion batteries using a fully enclosed liquid cell in a transmission electron microscope (TEM) to reveal early degradation that is not evident in the charge-discharge curves. To compare the electrochemical phase transformation behavior between three model materials, thin films of amorphous Si, crystalline Al, and crystalline Au were lithiated and delithiated at controlled rates while immersed in a commercial liquid electrolyte. This method allowed for the direct observation of lithiation mechanisms in nanoscale negative electrodes, revealing that a simplistic model of a surface-to-interior lithiation front is insufficient. For the crystalline films, a lithiation front spread laterally from a few initial nucleation points, with continued grain nucleation along the growing interface. The intermediate lithiated phases were identified using electron diffraction, and high-resolution postmortem imaging revealed the details of the final microstructure. Our results show that electrochemically induced solid-solid phase transformations can lead to highly concentrated stresses at the laterally propagating phase boundary which should be considered for future designs of nanostructured electrodes for Li-ion batteries.

  6. Lipid droplet pattern and nondroplet-like structure in two fat mutants of Caenorhabditis elegans revealed by coherent anti-Stokes Raman scattering microscopy

    Science.gov (United States)

    Yi, Yung-Hsiang; Chien, Cheng-Hao; Chen, Wei-Wen; Ma, Tian-Hsiang; Liu, Kuan-Yu; Chang, Yu-Sun; Chang, Ta-Chau; Lo, Szecheng J.

    2014-01-01

    Lipid is an important energy source and essential component for plasma and organelle membranes in all kinds of cells. Coherent anti-Stokes Raman scattering (CARS) microscopy is a label-free and nonlinear optical technique that can be used to monitor the lipid distribution in live organisms. Here, we utilize CARS microscopy to investigate the pattern of lipid droplets in two live Caenorhabditis elegans mutants (fat-2 and fat-3). The CARS images showed a striking decrease in the size, number, and content of lipid droplets in the fat-2 mutant but a slight difference in the fat-3 mutant as compared with the wild-type worm. Moreover, a nondroplet-like structure with enhanced CARS signal was detected for the first time in the uterus of fat-2 and fat-3 mutants. In addition, transgenic fat-2 mutant expressing a GFP fusion protein of vitellogenin-2 (a yolk lipoprotein) revealed that the enhanced CARS signal colocalized with the GFP signal, which suggests that the nondroplet-like structure is primarily due to the accumulation of yolk lipoproteins. Together, this study implies that CARS microscopy is a potential tool to study the distribution of yolk lipoproteins, in addition to lipid droplets, in live animals.

  7. Revealing the Cell-Material Interface with Nanometer Resolution by Focused Ion Beam/Scanning Electron Microscopy.

    Science.gov (United States)

    Santoro, Francesca; Zhao, Wenting; Joubert, Lydia-Marie; Duan, Liting; Schnitker, Jan; van de Burgt, Yoeri; Lou, Hsin-Ya; Liu, Bofei; Salleo, Alberto; Cui, Lifeng; Cui, Yi; Cui, Bianxiao

    2017-08-22

    The interface between cells and nonbiological surfaces regulates cell attachment, chronic tissue responses, and ultimately the success of medical implants or biosensors. Clinical and laboratory studies show that topological features of the surface profoundly influence cellular responses; for example, titanium surfaces with nano- and microtopographical structures enhance osteoblast attachment and host-implant integration as compared to a smooth surface. To understand how cells and tissues respond to different topographical features, it is of critical importance to directly visualize the cell-material interface at the relevant nanometer length scale. Here, we present a method for in situ examination of the cell-to-material interface at any desired location, based on focused ion beam milling and scanning electron microscopy imaging to resolve the cell membrane-to-material interface with 10 nm resolution. By examining how cell membranes interact with topographical features such as nanoscale protrusions or invaginations, we discovered that the cell membrane readily deforms inward and wraps around protruding structures, but hardly deforms outward to contour invaginating structures. This asymmetric membrane response (inward vs outward deformation) causes the cleft width between the cell membrane and the nanostructure surface to vary by more than an order of magnitude. Our results suggest that surface topology is a crucial consideration for the development of medical implants or biosensors whose performances are strongly influenced by the cell-to-material interface. We anticipate that the method can be used to explore the direct interaction of cells/tissue with medical devices such as metal implants in the future.

  8. FTIR microscopy reveals distinct biomolecular profile of crustacean digestive glands upon subtoxic exposure to ZnO nanoparticles.

    Science.gov (United States)

    Romih, Tea; Jemec, Anita; Novak, Sara; Vaccari, Lisa; Ferraris, Paolo; Šimon, Martin; Kos, Monika; Susič, Robert; Kogej, Ksenija; Zupanc, Jernej; Drobne, Damjana

    2016-01-01

    Biomolecular profiling with Fourier-Transform InfraRed Microscopy was performed to distinguish the Zn(2+)-mediated effects on the crustacean (Porcellio scaber) digestive glands from the ones elicited by the ZnO nanoparticles (NPs). The exposure to ZnO NPs or ZnCl2 (1500 and 4000 µg Zn/g of dry food) activated different types of metabolic pathways: some were found in the case of both substances, some only in the case of ZnCl2, and some only upon exposure to ZnO NPs. Both the ZnO NPs and the ZnCl2 increased the protein (∼1312 cm(-1); 1720-1485 cm(-1)/3000-2830 cm(-1)) and RNA concentration (∼1115 cm(-1)). At the highest exposure concentration of ZnCl2, where the effects occurred also at the organismal level, some additional changes were found that were not detected upon the ZnO NP exposure. These included changed carbohydrate (most likely glycogen) concentrations (∼1043 cm(-1)) and the desaturation of cell membrane lipids (∼3014 cm(-1)). The activation of novel metabolic pathways, as evidenced by changed proteins' structure (at 1274 cm(-1)), was found only in the case of ZnO NPs. This proves that Zn(2+) are not the only inducers of the response to ZnO NPs. Low bioavailable fraction of Zn(2+) in the digestive glands exposed to ZnO NPs further supports the role of particles in the ZnO NP-generated effects. This study provides the evidence that ZnO NPs induce their own metabolic responses in the subtoxic range.

  9. Synchrotron radiation X-ray fluorescence microscopy reveals a spatial association of copper on elastic laminae in rat aortic media.

    Science.gov (United States)

    Qin, Zhenyu; Toursarkissian, Boulos; Lai, Barry

    2011-08-01

    Copper, an essential trace metal in humans, plays an important role in elastic formation. However, little is known about the spatial association between copper, elastin, and elastin producing cells. The aorta is the largest artery; the aortic media is primarily composed of the elastic lamellae and vascular smooth muscle cells, which makes it a good model to address this issue. Synchrotron radiation X-ray fluorescence microscopy (SRXRF) is a new generation technique to investigate the spatial topography of trace metals in biological samples. Recently, we utilized this technique to determine the topography of copper as well as other trace elements in aortic media of Sprague Dawley rats. A standard rat diet was used to feed Sprague Dawley rats, which contains the normal dietary requirements of copper and zinc. Paraffin embedded segments (4 μm of thickness) of thoracic aorta were analyzed using a 10 keV incident monochromatic X-ray beam focusing on a spot size of 0.3 μm × 0.2 μm (horizontal × vertical). The X-ray spectrum was measured using an energy-dispersive silicon drift detector for elemental topography. Our results showed that phosphorus, sulfur, and zinc are predominately distributed in the vascular smooth muscle cells, whereas copper is dramatically accumulated in elastic laminae, indicating a preferential spatial association of copper on elastic laminae in aortic media. This finding sheds new light on the role of copper in elastic formation. Our studies also demonstrate that SRXRF allows for the visualization of trace elements in tissues and cells of rodent aorta with high spatial resolution and provides an opportunity to study the role of trace elements in vasculature.

  10. In Situ Microscopy Analysis Reveals Local Innate Immune Response Developed around Brucella Infected Cells in Resistant and Susceptible Mice

    Science.gov (United States)

    Copin, Richard; Vitry, Marie-Alice; Hanot Mambres, Delphine; Machelart, Arnaud; De Trez, Carl; Vanderwinden, Jean-Marie; Magez, Stefan; Akira, Shizuo; Ryffel, Bernhard; Carlier, Yves; Letesson, Jean-Jacques; Muraille, Eric

    2012-01-01

    Brucella are facultative intracellular bacteria that chronically infect humans and animals causing brucellosis. Brucella are able to invade and replicate in a broad range of cell lines in vitro, however the cells supporting bacterial growth in vivo are largely unknown. In order to identify these, we used a Brucella melitensis strain stably expressing mCherry fluorescent protein to determine the phenotype of infected cells in spleen and liver, two major sites of B. melitensis growth in mice. In both tissues, the majority of primary infected cells expressed the F4/80 myeloid marker. The peak of infection correlated with granuloma development. These structures were mainly composed of CD11b+ F4/80+ MHC-II+ cells expressing iNOS/NOS2 enzyme. A fraction of these cells also expressed CD11c marker and appeared similar to inflammatory dendritic cells (DCs). Analysis of genetically deficient mice revealed that differentiation of iNOS+ inflammatory DC, granuloma formation and control of bacterial growth were deeply affected by the absence of MyD88, IL-12p35 and IFN-γ molecules. During chronic phase of infection in susceptible mice, we identified a particular subset of DC expressing both CD11c and CD205, serving as a reservoir for the bacteria. Taken together, our results describe the cellular nature of immune effectors involved during Brucella infection and reveal a previously unappreciated role for DC subsets, both as effectors and reservoir cells, in the pathogenesis of brucellosis. PMID:22479178

  11. In-situ atomic force microscopy observation revealing gel-like plasticity on a metallic glass surface

    Science.gov (United States)

    Lu, Y. M.; Zeng, J. F.; Huang, J. C.; Kuan, S. Y.; Nieh, T. G.; Wang, W. H.; Pan, M. X.; Liu, C. T.; Yang, Y.

    2017-03-01

    It has been decade-long and enduring efforts to decipher the structural mechanism of plasticity in metallic glasses; however, it still remains a challenge to directly reveal the structural change, if any, that precedes; and dominant plastics flow in them. Here, by using the dynamic atomic force microscope as an "imaging" as well as a "forcing" tool, we unfold a real-time sequence of structural evolution occurring on the surface of an Au-Si thin film metallic glass. In sharp contrast to the common notion that plasticity comes along with mechanical softening in bulk metallic glasses, our experimental results directly reveal three types of nano-sized surface regions, which undergo plasticity but exhibit different characters of structural evolution following the local plasticity events, including stochastic structural rearrangement, unusual local relaxation and rejuvenation. As such, yielding on the metallic-glass surface manifests as a dynamic equilibrium between local relaxation and rejuvenation as opposed to shear instability in bulk metallic-glasses. Our finding demonstrates that plasticity on the metallic glass surface of Au-Si metallic glass bears much resemblance to that of the colloidal gels, of which nonlinear rheology rather than shear instability governs the constitutive behavior of plasticity.

  12. Atomic force microscopy reveals age-dependent changes in nanomechanical properties of the extracellular matrix of native human menisci: implications for joint degeneration and osteoarthritis.

    Science.gov (United States)

    Kwok, Jeanie; Grogan, Shawn; Meckes, Brian; Arce, Fernando; Lal, Ratnesh; D'Lima, Darryl

    2014-11-01

    With aging, the menisci become more susceptible to degeneration due to sustained mechanical stress accompanied by age-related changes in the extracellular matrix (ECM). However, the mechanistic relationship between age-related meniscal degeneration and osteoarthritis (OA) development is not yet fully understood. We have examined the nanomechanical properties of the ECM of normal, aged, and degenerated human menisci using atomic force microscopy (AFM). Elasticity maps of the ECM revealed a unique differential qualitative nanomechanical profile of healthy young tissue: prominent unimodal peaks in the elastic moduli distribution in each region (outer, middle, and inner). Healthy aged tissue showed similar regional elasticity but with both unimodal and bimodal distributions that included higher elastic moduli. In contrast, degenerated OA tissue showed the broadest distribution without prominent peaks indicative of substantially increased mechanical heterogeneity in the ECM. AFM analysis reveals distinct regional nanomechanical profiles that underlie aging-dependent tissue degeneration and OA. The authors of this study used atomic force microscopy to determine the nanomechanical properties of the extracellular matrix in normal and degenerated human menisci, as well as in menisci undergoing healthy aging. Comparison of these properties help to understand the relationship between healthy ageing, and age-dependent joint degeneration and osteoarthritis. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Time-lapse ultrashort pulse microscopy of infection in three-dimensional versus two-dimensional culture environments reveals enhanced extra-chromosomal virus replication compartment formation

    Science.gov (United States)

    Gibbs, Holly C.; Sing, Garwin; Armas, Juan Carlos González; Campbell, Colin J.; Ghazal, Peter; Yeh, Alvin T.

    2013-03-01

    The mechanisms that enable viruses to harness cellular machinery for their own survival are primarily studied in cell lines cultured in two-dimensional (2-D) environments. However, there are increasing reports of biological differences between cells cultured in 2-D versus three-dimensional (3-D) environments. Here we report differences in host-virus interactions based on differences in culture environment. Using ultrashort pulse microscopy (UPM), a form of two-photon microscopy that utilizes sub-10-fs pulses to efficiently excite fluorophores, we have shown that de novo development of extra-chromosomal virus replication compartments (VRCs) upon murine cytomegalovirus (mCMV) infection is markedly enhanced when host cells are cultured in 3-D collagen gels versus 2-D monolayers. In addition, time-lapse imaging revealed that mCMV-induced VRCs have the capacity to grow by coalescence. This work supports the future potential of 3-D culture as a useful bridge between traditional monolayer cultures and animal models to study host-virus interactions in a more physiologically relevant environment for the development of effective anti-viral therapeutics. These advances will require broader adoption of modalities, such as UPM, to image deep within scattering tissues.

  14. Unsupervised clustering of subcellular protein expression patterns in high-throughput microscopy images reveals protein complexes and functional relationships between proteins.

    Science.gov (United States)

    Handfield, Louis-François; Chong, Yolanda T; Simmons, Jibril; Andrews, Brenda J; Moses, Alan M

    2013-01-01

    Protein subcellular localization has been systematically characterized in budding yeast using fluorescently tagged proteins. Based on the fluorescence microscopy images, subcellular localization of many proteins can be classified automatically using supervised machine learning approaches that have been trained to recognize predefined image classes based on statistical features. Here, we present an unsupervised analysis of protein expression patterns in a set of high-resolution, high-throughput microscope images. Our analysis is based on 7 biologically interpretable features which are evaluated on automatically identified cells, and whose cell-stage dependency is captured by a continuous model for cell growth. We show that it is possible to identify most previously identified localization patterns in a cluster analysis based on these features and that similarities between the inferred expression patterns contain more information about protein function than can be explained by a previous manual categorization of subcellular localization. Furthermore, the inferred cell-stage associated to each fluorescence measurement allows us to visualize large groups of proteins entering the bud at specific stages of bud growth. These correspond to proteins localized to organelles, revealing that the organelles must be entering the bud in a stereotypical order. We also identify and organize a smaller group of proteins that show subtle differences in the way they move around the bud during growth. Our results suggest that biologically interpretable features based on explicit models of cell morphology will yield unprecedented power for pattern discovery in high-resolution, high-throughput microscopy images.

  15. Unsupervised clustering of subcellular protein expression patterns in high-throughput microscopy images reveals protein complexes and functional relationships between proteins.

    Directory of Open Access Journals (Sweden)

    Louis-François Handfield

    Full Text Available Protein subcellular localization has been systematically characterized in budding yeast using fluorescently tagged proteins. Based on the fluorescence microscopy images, subcellular localization of many proteins can be classified automatically using supervised machine learning approaches that have been trained to recognize predefined image classes based on statistical features. Here, we present an unsupervised analysis of protein expression patterns in a set of high-resolution, high-throughput microscope images. Our analysis is based on 7 biologically interpretable features which are evaluated on automatically identified cells, and whose cell-stage dependency is captured by a continuous model for cell growth. We show that it is possible to identify most previously identified localization patterns in a cluster analysis based on these features and that similarities between the inferred expression patterns contain more information about protein function than can be explained by a previous manual categorization of subcellular localization. Furthermore, the inferred cell-stage associated to each fluorescence measurement allows us to visualize large groups of proteins entering the bud at specific stages of bud growth. These correspond to proteins localized to organelles, revealing that the organelles must be entering the bud in a stereotypical order. We also identify and organize a smaller group of proteins that show subtle differences in the way they move around the bud during growth. Our results suggest that biologically interpretable features based on explicit models of cell morphology will yield unprecedented power for pattern discovery in high-resolution, high-throughput microscopy images.

  16. Unsupervised Clustering of Subcellular Protein Expression Patterns in High-Throughput Microscopy Images Reveals Protein Complexes and Functional Relationships between Proteins

    Science.gov (United States)

    Handfield, Louis-François; Chong, Yolanda T.; Simmons, Jibril; Andrews, Brenda J.; Moses, Alan M.

    2013-01-01

    Protein subcellular localization has been systematically characterized in budding yeast using fluorescently tagged proteins. Based on the fluorescence microscopy images, subcellular localization of many proteins can be classified automatically using supervised machine learning approaches that have been trained to recognize predefined image classes based on statistical features. Here, we present an unsupervised analysis of protein expression patterns in a set of high-resolution, high-throughput microscope images. Our analysis is based on 7 biologically interpretable features which are evaluated on automatically identified cells, and whose cell-stage dependency is captured by a continuous model for cell growth. We show that it is possible to identify most previously identified localization patterns in a cluster analysis based on these features and that similarities between the inferred expression patterns contain more information about protein function than can be explained by a previous manual categorization of subcellular localization. Furthermore, the inferred cell-stage associated to each fluorescence measurement allows us to visualize large groups of proteins entering the bud at specific stages of bud growth. These correspond to proteins localized to organelles, revealing that the organelles must be entering the bud in a stereotypical order. We also identify and organize a smaller group of proteins that show subtle differences in the way they move around the bud during growth. Our results suggest that biologically interpretable features based on explicit models of cell morphology will yield unprecedented power for pattern discovery in high-resolution, high-throughput microscopy images. PMID:23785265

  17. Enhanced detection with spectral imaging fluorescence microscopy reveals tissue- and cell-type-specific compartmentalization of surface-modified polystyrene nanoparticles.

    Science.gov (United States)

    Kenesei, Kata; Murali, Kumarasamy; Czéh, Árpád; Piella, Jordi; Puntes, Victor; Madarász, Emília

    2016-07-07

    , macrophages accumulated large amount of carboxylated and PEGylated nanoparticles, with detectable redistribution from the marginal zone to the white pulp during the 4-day survival period. Spectral imaging fluorescence microscopy allowed detecting the tissue- and cell-type-specific accumulation and barrier-penetration of polystyrene nanoparticles with equal size but chemically distinct surfaces. The data revealed that polystyrene nanoparticles are retained by the reticuloendothelial system regardless of surface functionalization. Taken together with the increasing production and use of nanoparticles, the results highlight the necessity of long-term distribution studies to estimate the potential health-risks implanted by tissue-specific nanoparticle accumulation and clearance.

  18. The Video Generation.

    Science.gov (United States)

    Provenzo, Eugene F., Jr.

    1992-01-01

    Video games are neither neutral nor harmless but represent very specific social and symbolic constructs. Research on the social content of today's video games reveals that sex bias and gender stereotyping are widely evident throughout the Nintendo games. Violence and aggression also pervade the great majority of the games. (MLF)

  19. Correlated Light Microscopy and Electron Microscopy

    NARCIS (Netherlands)

    Sjollema, Klaas A.; Schnell, Ulrike; Kuipers, Jeroen; Kalicharan, Ruby; Giepmans, Ben N. G.; MullerReichert, T; Verkade, P

    2012-01-01

    Understanding where, when, and how biomolecules (inter)act is crucial to uncover fundamental mechanisms in cell biology. Recent developments in fluorescence light microscopy (FLM) allow protein imaging in living cells and at the near molecular level. However, fluorescence microscopy only reveals

  20. Video microblogging

    DEFF Research Database (Denmark)

    Bornoe, Nis; Barkhuus, Louise

    2010-01-01

    Microblogging is a recently popular phenomenon and with the increasing trend for video cameras to be built into mobile phones, a new type of microblogging has entered the arena of electronic communication: video microblogging. In this study we examine video microblogging, which is the broadcasting...... of short videos. A series of semi-structured interviews offers an understanding of why and how video microblogging is used and what the users post and broadcast....

  1. Correlative STED and Atomic Force Microscopy on Live Astrocytes Reveals Plasticity of Cytoskeletal Structure and Membrane Physical Properties during Polarized Migration

    Directory of Open Access Journals (Sweden)

    Nathalie Rouach

    2017-04-01

    Full Text Available The plasticity of the cytoskeleton architecture and membrane properties is important for the establishment of cell polarity, adhesion and migration. Here, we present a method which combines stimulated emission depletion (STED super-resolution imaging and atomic force microscopy (AFM to correlate cytoskeletal structural information with membrane physical properties in live astrocytes. Using STED compatible dyes for live cell imaging of the cytoskeleton, and simultaneously mapping the cell surface topology with AFM, we obtain unprecedented detail of highly organized networks of actin and microtubules in astrocytes. Combining mechanical data from AFM with optical imaging of actin and tubulin further reveals links between cytoskeleton organization and membrane properties. Using this methodology we illustrate that scratch-induced migration induces cytoskeleton remodeling. The latter is caused by a polarization of actin and microtubule elements within astroglial cell processes, which correlates strongly with changes in cell stiffness. The method opens new avenues for the dynamic probing of the membrane structural and functional plasticity of living brain cells. It is a powerful tool for providing new insights into mechanisms of cell structural remodeling during physiological or pathological processes, such as brain development or tumorigenesis.

  2. A novel technique using potassium permanganate and reflectance confocal microscopy to image biofilm extracellular polymeric matrix reveals non-eDNA networks in Pseudomonas aeruginosa biofilms.

    Science.gov (United States)

    Swearingen, Matthew C; Mehta, Ajeet; Mehta, Amar; Nistico, Laura; Hill, Preston J; Falzarano, Anthony R; Wozniak, Daniel J; Hall-Stoodley, Luanne; Stoodley, Paul

    2016-02-01

    Biofilms are etiologically important in the development of chronic medical and dental infections. The biofilm extracellular polymeric substance (EPS) determines biofilm structure and allows bacteria in biofilms to adapt to changes in mechanical loads such as fluid shear. However, EPS components are difficult to visualize microscopically because of their low density and molecular complexity. Here, we tested potassium permanganate, KMnO4, for use as a non-specific EPS contrast-enhancing stain using confocal laser scanning microscopy in reflectance mode. We demonstrate that KMnO4 reacted with EPS components of various strains of Pseudomonas, Staphylococcus and Streptococcus, yielding brown MnO2 precipitate deposition on the EPS, which was quantifiable using data from the laser reflection detector. Furthermore, the MnO2 signal could be quantified in combination with fluorescent nucleic acid staining. COMSTAT image analysis indicated that KMnO4 staining increased the estimated biovolume over that determined by nucleic acid staining alone for all strains tested, and revealed non-eDNA EPS networks in Pseudomonas aeruginosa biofilm. In vitro and in vivo testing indicated that KMnO4 reacted with poly-N-acetylglucosamine and Pseudomonas Pel polysaccharide, but did not react strongly with DNA or alginate. KMnO4 staining may have application as a research tool and for diagnostic potential for biofilms in clinical samples. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  3. Fluorescence microscopy of Streptomyces conjugation suggests DNA-transfer at the lateral walls and reveals the spreading of the plasmid in the recipient mycelium.

    Science.gov (United States)

    Thoma, Lina; Vollmer, Bernd; Muth, Günther

    2016-02-01

    Conjugative DNA-transfer in mycelial streptomycetes is a unique process, manifested on agar plates by the formation of circular growth retardation zones called pocks. Because pock size correlates with the extent of the transconjugant zone, it was suggested that pocks reflect the spreading of the transferred plasmid in the recipient mycelium. However, this concept has not been experimentally proven yet. The use of an eGFP-encoding derivative of the conjugative pIJ303 plasmid and Streptomyces lividans T7-mCherry as recipient enabled us to differentiate donor, recipient and transconjugant hyphae in mating experiments by fluorescence microscopy. Microscopic observation of the conjugation process suggested DNA-transfer via the lateral walls. At the contact sites mCherry was never observed in the donor, indicating that the conjugative DNA-transfer does not involve interfusion of cytoplasms of donor and recipient. The spreading of the transferred plasmid to the older parts of the recipient mycelium was demonstrated. This spreading was impaired when plasmid-encoded spd genes were inactivated. Deletion of the FtsK-like DNA-translocase encoding tra gene from the plasmid and mating experiments with strains containing chromosomal copies of tra either in the donor and/or in the recipient revealed that Tra had an essential role in intramycelial plasmid spreading. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  4. Automated video analysis system reveals distinct diurnal behaviors in C57BL/6 and C3H/HeN mice.

    Science.gov (United States)

    Adamah-Biassi, E B; Stepien, I; Hudson, R L; Dubocovich, M L

    2013-04-15

    Advances in rodent behavior dissection using automated video recording and analysis allows detailed phenotyping. This study compared and contrasted 15 diurnal behaviors recorded continuously using an automated behavioral analysis system for a period of 14 days under a 14/10 light/dark cycle in single housed C3H/HeN (C3H) or C57BL/6 (C57) male mice. Diurnal behaviors, recorded with minimal experimental interference and analyzed using phenotypic array and temporal distribution analysis showed bimodal and unimodal profiles in the C57 and C3H mice, respectively. Phenotypic array analysis revealed distinct behavioral rhythms in Activity-Like Behaviors (i.e. walk, hang, jump, come down) (ALB), Exploration-Like Behaviors (i.e. dig, groom, rear up, sniff, stretch) (ELB), Ingestion-Like Behaviors (i.e. drink, eat) (ILB) and Resting-Like Behaviors (i.e. awake, remain low, rest, twitch) (RLB) of C3H and C57 mice. Temporal distribution analysis demonstrated that strain and time of day affects the magnitude and distribution of the spontaneous homecage behaviors. Wheel running activity, water and food measurements correlated with timing of homecage behaviors. Subcutaneous (3 mg/kg, sc) or oral (0.02 mg/ml, oral) melatonin treatments in C57 mice did not modify either the total 24 h magnitude or temporal distribution of homecage behaviors when compared with vehicle treatments. We conclude that C3H and C57 mice show different spontaneous activity and behavioral rhythms specifically during the night period which are not modulated by melatonin. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Video demystified

    CERN Document Server

    Jack, Keith

    2004-01-01

    This international bestseller and essential reference is the "bible" for digital video engineers and programmers worldwide. This is by far the most informative analog and digital video reference available, includes the hottest new trends and cutting-edge developments in the field. Video Demystified, Fourth Edition is a "one stop" reference guide for the various digital video technologies. The fourth edition is completely updated with all new chapters on MPEG-4, H.264, SDTV/HDTV, ATSC/DVB, and Streaming Video (Video over DSL, Ethernet, etc.), as well as discussions of the latest standards throughout. The accompanying CD-ROM is updated to include a unique set of video test files in the newest formats. *This essential reference is the "bible" for digital video engineers and programmers worldwide *Contains all new chapters on MPEG-4, H.264, SDTV/HDTV, ATSC/DVB, and Streaming Video *Completely revised with all the latest and most up-to-date industry standards.

  6. Social video content delivery

    CERN Document Server

    Wang, Zhi; Zhu, Wenwu

    2016-01-01

    This brief presents new architecture and strategies for distribution of social video content. A primary framework for socially-aware video delivery and a thorough overview of the possible approaches is provided. The book identifies the unique characteristics of socially-aware video access and social content propagation, revealing the design and integration of individual modules that are aimed at enhancing user experience in the social network context. The change in video content generation, propagation, and consumption for online social networks, has significantly challenged the traditional video delivery paradigm. Given the massive amount of user-generated content shared in online social networks, users are now engaged as active participants in the social ecosystem rather than as passive receivers of media content. This revolution is being driven further by the deep penetration of 3G/4G wireless networks and smart mobile devices that are seamlessly integrated with online social networking and media-sharing s...

  7. Synchrotron soft X-ray imaging and fluorescence microscopy reveal novel features of asbestos body morphology and composition in human lung tissues

    Directory of Open Access Journals (Sweden)

    Polentarutti Maurizio

    2011-02-01

    Full Text Available Abstract Background Occupational or environmental exposure to asbestos fibres is associated with pleural and parenchymal lung diseases. A histopathologic hallmark of exposure to asbestos is the presence in lung parenchyma of the so-called asbestos bodies. They are the final product of biomineralization processes resulting in deposition of endogenous iron and organic matter (mainly proteins around the inhaled asbestos fibres. For shedding light on the formation mechanisms of asbestos bodies it is of fundamental importance to characterize at the same length scales not only their structural morphology and chemical composition but also to correlate them to the possible alterations in the local composition of the surrounding tissues. Here we report the first correlative morphological and chemical characterization of untreated paraffinated histological lung tissue samples with asbestos bodies by means of soft X-ray imaging and X-Ray Fluorescence (XRF microscopy, which reveals new features in the elemental lateral distribution. Results The X-ray absorption and phase contrast images and the simultaneously monitored XRF maps of tissue samples have revealed the location, distribution and elemental composition of asbestos bodies and associated nanometric structures. The observed specific morphology and differences in the local Si, Fe, O and Mg content provide distinct fingerprints characteristic for the core asbestos fibre and the ferruginous body. The highest Si content is found in the asbestos fibre, while the shell and ferruginous bodies are characterized by strongly increased content of Mg, Fe and O compared to the adjacent tissue. The XRF and SEM-EDX analyses of the extracted asbestos bodies confirmed an enhanced Mg deposition in the organic asbestos coating. Conclusions The present report demonstrates the potential of the advanced synchrotron-based X-ray imaging and microspectroscopy techniques for studying the response of the lung tissue to the

  8. Innovative Solution to Video Enhancement

    Science.gov (United States)

    2001-01-01

    Through a licensing agreement, Intergraph Government Solutions adapted a technology originally developed at NASA's Marshall Space Flight Center for enhanced video imaging by developing its Video Analyst(TM) System. Marshall's scientists developed the Video Image Stabilization and Registration (VISAR) technology to help FBI agents analyze video footage of the deadly 1996 Olympic Summer Games bombing in Atlanta, Georgia. VISAR technology enhanced nighttime videotapes made with hand-held camcorders, revealing important details about the explosion. Intergraph's Video Analyst System is a simple, effective, and affordable tool for video enhancement and analysis. The benefits associated with the Video Analyst System include support of full-resolution digital video, frame-by-frame analysis, and the ability to store analog video in digital format. Up to 12 hours of digital video can be stored and maintained for reliable footage analysis. The system also includes state-of-the-art features such as stabilization, image enhancement, and convolution to help improve the visibility of subjects in the video without altering underlying footage. Adaptable to many uses, Intergraph#s Video Analyst System meets the stringent demands of the law enforcement industry in the areas of surveillance, crime scene footage, sting operations, and dash-mounted video cameras.

  9. Digital video.

    Science.gov (United States)

    Johnson, Don; Johnson, Mike

    2004-04-01

    The process of digital capture, editing, and archiving video has become an important aspect of documenting arthroscopic surgery. Recording the arthroscopic findings before and after surgery is an essential part of the patient's medical record. The hardware and software has become more reasonable to purchase, but the learning curve to master the software is steep. Digital video is captured at the time of arthroscopy to a hard disk, and written to a CD at the end of the operative procedure. The process of obtaining video of open procedures is more complex. Outside video of the procedure is recorded on digital tape with a digital video camera. The camera must be plugged into a computer to capture the video on the hard disk. Adobe Premiere software is used to edit the video and render the finished video to the hard drive. This finished video is burned onto a CD. We outline the choice of computer hardware and software for the manipulation of digital video. The techniques of backup and archiving the completed projects and files also are outlined. The uses of digital video for education and the formats that can be used in PowerPoint presentations are discussed.

  10. Electron microscopy and in vitro deneddylation reveal similar architectures and biochemistry of isolated human and Flag-mouse COP9 signalosome complexes

    Energy Technology Data Exchange (ETDEWEB)

    Rockel, Beate [Department of Molecular Structural Biology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried (Germany); Schmaler, Tilo; Huang, Xiaohua [Division of Molecular Biology, Department of General, Visceral, Vascular and Thoracic Surgery, Charité – Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin (Germany); Dubiel, Wolfgang, E-mail: Wolfgang.dubiel@charite.de [Division of Molecular Biology, Department of General, Visceral, Vascular and Thoracic Surgery, Charité – Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin (Germany)

    2014-07-25

    Highlights: • Deneddylation rates of human erythrocyte and mouse fibroblast CSN are very similar. • 3D models of native human and mouse CSN reveal common architectures. • The cryo-structure of native mammalian CSN shows a horseshoe subunit arrangement. - Abstract: The COP9 signalosome (CSN) is a regulator of the ubiquitin (Ub) proteasome system (UPS). In the UPS, proteins are Ub-labeled for degradation by Ub ligases conferring substrate specificity. The CSN controls a large family of Ub ligases called cullin-RING ligases (CRLs), which ubiquitinate cell cycle regulators, transcription factors and DNA damage response proteins. The CSN possesses structural similarities with the 26S proteasome Lid complex and the translation initiation complex 3 (eIF3) indicating similar ancestry and function. Initial structures were obtained 14 years ago by 2D electron microscopy (EM). Recently, first 3D molecular models of the CSN were created on the basis of negative-stain EM and single-particle analysis, mostly with recombinant complexes. Here, we compare deneddylating activity and structural features of CSN complexes purified in an elaborate procedure from human erythrocytes and efficiently pulled down from mouse Flag-CSN2 B8 fibroblasts. In an in vitro deneddylation assay both the human and the mouse CSN complexes deneddylated Nedd8-Cul1 with comparable rates. 3D structural models of the erythrocyte CSN as well as of the mouse Flag-CSN were generated by negative stain EM and by cryo-EM. Both complexes show a central U-shaped segment from which several arms emanate. This structure, called the horseshoe, is formed by the PCI domain subunits. CSN5 and CSN6 point away from the horseshoe. Compared to 3D models of negatively stained CSN complexes, densities assigned to CSN2 and CSN4 are better defined in the cryo-map. Because biochemical and structural results obtained with CSN complexes isolated from human erythrocytes and purified by Flag-CSN pulldown from mouse B8 fibroblasts

  11. Fluorescence microscopy.

    Science.gov (United States)

    Sanderson, Michael J; Smith, Ian; Parker, Ian; Bootman, Martin D

    2014-10-01

    Fluorescence microscopy is a major tool with which to monitor cell physiology. Although the concepts of fluorescence and its optical separation using filters remain similar, microscope design varies with the aim of increasing image contrast and spatial resolution. The basics of wide-field microscopy are outlined to emphasize the selection, advantages, and correct use of laser scanning confocal microscopy, two-photon microscopy, scanning disk confocal microscopy, total internal reflection, and super-resolution microscopy. In addition, the principles of how these microscopes form images are reviewed to appreciate their capabilities, limitations, and constraints for operation. © 2014 Cold Spring Harbor Laboratory Press.

  12. Immersive video

    Science.gov (United States)

    Moezzi, Saied; Katkere, Arun L.; Jain, Ramesh C.

    1996-03-01

    Interactive video and television viewers should have the power to control their viewing position. To make this a reality, we introduce the concept of Immersive Video, which employs computer vision and computer graphics technologies to provide remote users a sense of complete immersion when viewing an event. Immersive Video uses multiple videos of an event, captured from different perspectives, to generate a full 3D digital video of that event. That is accomplished by assimilating important information from each video stream into a comprehensive, dynamic, 3D model of the environment. Using this 3D digital video, interactive viewers can then move around the remote environment and observe the events taking place from any desired perspective. Our Immersive Video System currently provides interactive viewing and `walkthrus' of staged karate demonstrations, basketball games, dance performances, and typical campus scenes. In its full realization, Immersive Video will be a paradigm shift in visual communication which will revolutionize television and video media, and become an integral part of future telepresence and virtual reality systems.

  13. Electron Microscopy.

    Science.gov (United States)

    Beer, Michael

    1980-01-01

    Reviews technical aspects of structure determination in biological electron microscopy (EM). Discusses low dose EM, low temperature microscopy, electron energy loss spectra, determination of mass or molecular weight, and EM of labeled systems. Cites 34 references. (CS)

  14. Morphology, Crystallization, and Melting of Single Crystals and Thin Films of Star-branched Polyesters with Poly(E-caprolactone) Arms as Revealed by Atomic Force Microscopy

    NARCIS (Netherlands)

    Nunez Calzado, M.E.; Nunez, E.; Vancso, Gyula J.; Gedde, U.W.

    2008-01-01

    The morphology and thermal stability of different sectors in solution- and melt-grown crystals of star-branched polyesters with poly(ε-caprolactone) (PCL) arms, and of a reference linear PCL, have been studied by tapping-mode atomic-force microscopy (AFM). Real-time monitoring of

  15. Video games

    OpenAIRE

    Kolář, Vojtěch

    2012-01-01

    This thesis is based on a detailed analysis of various topics related to the question of whether video games can be art. In the first place it analyzes the current academic discussion on this subject and confronts different opinions of both supporters and objectors of the idea, that video games can be a full-fledged art form. The second point of this paper is to analyze the properties, that are inherent to video games, in order to find the reason, why cultural elite considers video games as i...

  16. Mineralogical composition and phase-to-phase relationships in natural hydraulic lime and/or natural cement - raw materials and burnt products revealed by scanning electron microscopy

    Science.gov (United States)

    Kozlovcev, Petr; Přikryl, Richard; Racek, Martin; Přikrylová, Jiřina

    2016-04-01

    In contrast to modern process of production of cement clinker, traditional burning of natural hydraulic lime below sintering temperature relied on the formation of new phases from ion migration between neighbouring mineral grains composing raw material. The importance of the mineralogical composition and spatial distribution of rock-forming minerals in impure limestones used as a raw material for natural hydraulic lime presents not well explored issue in the scientific literature. To fill this gap, the recent study focuses in detailed analysis of experimentally burnt impure limestones (mostly from Barrandian area, Bohemian Massif). The phase changes were documented by optical microscopy, X-ray diffraction, and scanning electron microscopy with an energy dispersive spectrometer (SEM-EDS) coupled with x-ray elemental mapping. The latest allowed for visualization of distribution of elements within raw materials and burnt products. SEM/EDS study brought valuable data on the presence of transitional and/or minor phases, which were poorly detectable by other methods.

  17. Effect of Actin Organization on the Stiffness of Living Breast Cancer Cells Revealed by Peak-Force Modulation Atomic Force Microscopy.

    Science.gov (United States)

    Calzado-Martín, Alicia; Encinar, Mario; Tamayo, Javier; Calleja, Montserrat; San Paulo, Alvaro

    2016-03-22

    We study the correlation between cytoskeleton organization and stiffness of three epithelial breast cancer cells lines with different degrees of malignancy: MCF-10A (healthy), MCF-7 (tumorigenic/noninvasive), and MDA-MB-231 (tumorigenic/invasive). Peak-force modulation atomic force microscopy is used for high-resolution topography and stiffness imaging of actin filaments within living cells. In healthy cells, local stiffness is maximum where filamentous actin is organized as well-aligned stress fibers, resulting in apparent Young's modulus values up to 1 order of magnitude larger than those in regions where these structures are not observed, but these organized actin fibers are barely observed in tumorigenic cells. We further investigate cytoskeleton conformation in the three cell lines by immunofluorescence confocal microscopy. The combination of both techniques determines that actin stress fibers are present at apical regions of healthy cells, while in tumorigenic cells they appear only at basal regions, where they cannot contribute to stiffness as probed by atomic force microscopy. These results substantiate that actin stress fibers provide a dominant contribution to stiffness in healthy cells, while the elasticity of tumorigenic cells appears not predominantly determined by these structures. We also discuss the effects of the high-frequency indentations inherent to peak-force atomic force microscopy for the identification of mechanical cancer biomarkers. Whereas conventional low loading rate indentations (1 Hz) result in slightly differentiated average stiffness for each cell line, in high-frequency measurements (250 Hz) healthy cells are clearly discernible from both tumorigenic cells with an enhanced stiffness ratio; however, the two cancerous cell lines produced indistinguishable results.

  18. 61214++++','DOAJ-ART-EN'); return false;" href="+++++https://jual.nipissingu.ca/wp-content/uploads/sites/25/2014/06/v61214.m4v">61214++++">Jailed - Video

    Directory of Open Access Journals (Sweden)

    Cameron CULBERT

    2012-07-01

    Full Text Available As the public education system in Northern Ontario continues to take a downward spiral, a plethora of secondary school students are being placed in an alternative educational environment. Juxtaposing the two educational settings reveals very similar methods and characteristics of educating our youth as opposed to using a truly alternative approach to education. This video reviews the relationship between public education and alternative education in a remote Northern Ontario setting. It is my belief that the traditional methods of teaching are not appropriate in educating at risk students in alternative schools. Paper and pencil worksheets do not motivate these students to learn and succeed. Alternative education should emphasize experiential learning, a just in time curriculum based on every unique individual and the students true passion for everyday life. Cameron Culbert was born on February 3rd, 1977 in North Bay, Ontario. His teenage years were split between attending public school and his willed curriculum on the ski hill. Culbert spent 10 years (1996-2002 & 2006-2010 competing for Canada as an alpine ski racer. His passion for teaching and coaching began as an athlete and has now transferred into the classroom and the community. As a graduate of Nipissing University (BA, BEd, MEd. Camerons research interests are alternative education, physical education and technology in the classroom. Currently Cameron is an active educator and coach in Northern Ontario.

  19. 3D-SIM super resolution microscopy reveals a bead-like arrangement for FtsZ and the division machinery: implications for triggering cytokinesis.

    Directory of Open Access Journals (Sweden)

    Michael P Strauss

    Full Text Available FtsZ is a tubulin-like GTPase that is the major cytoskeletal protein in bacterial cell division. It polymerizes into a ring, called the Z ring, at the division site and acts as a scaffold to recruit other division proteins to this site as well as providing a contractile force for cytokinesis. To understand how FtsZ performs these functions, the in vivo architecture of the Z ring needs to be established, as well as how this structure constricts to enable cytokinesis. Conventional wide-field fluorescence microscopy depicts the Z ring as a continuous structure of uniform density. Here we use a form of super resolution microscopy, known as 3D-structured illumination microscopy (3D-SIM, to examine the architecture of the Z ring in cells of two Gram-positive organisms that have different cell shapes: the rod-shaped Bacillus subtilis and the coccoid Staphylococcus aureus. We show that in both organisms the Z ring is composed of a heterogeneous distribution of FtsZ. In addition, gaps of fluorescence were evident, which suggest that it is a discontinuous structure. Time-lapse studies using an advanced form of fast live 3D-SIM (Blaze support a model of FtsZ localization within the Z ring that is dynamic and remains distributed in a heterogeneous manner. However, FtsZ dynamics alone do not trigger the constriction of the Z ring to allow cytokinesis. Lastly, we visualize other components of the divisome and show that they also adopt a bead-like localization pattern at the future division site. Our data lead us to propose that FtsZ guides the divisome to adopt a similar localization pattern to ensure Z ring constriction only proceeds following the assembly of a mature divisome.

  20. In-vivo nonlinear optical microscopy (NLOM) of epithelial-connective tissue interface (ECTI) reveals quantitative measures of neoplasia in hamster oral mucosa.

    Science.gov (United States)

    Pal, Rahul; Yang, Jinping; Ortiz, Daniel; Qiu, Suimin; Resto, Vicente; McCammon, Susan; Vargas, Gracie

    2015-01-01

    The epithelial-connective tissue interface (ECTI) plays an integral role in epithelial neoplasia, including oral squamous cell carcinoma (OSCC). This interface undergoes significant alterations due to hyperproliferating epithelium that supports the transformation of normal epithelium to precancers and cancer. We present a method based on nonlinear optical microscopy to directly assess the ECTI and quantify dysplastic alterations using a hamster model for oral carcinogenesis. Neoplastic and non-neoplastic normal mucosa were imaged in-vivo by both multiphoton autofluorescence microscopy (MPAM) and second harmonic generation microscopy (SHGM) to obtain cross-sectional reconstructions of the oral epithelium and lamina propria. Imaged sites were biopsied and processed for histopathological grading and measurement of ECTI parameters. An ECTI shape parameter was calculated based on deviation from the linear geometry (ΔLinearity) seen in normal mucosa was measured using MPAM-SHGM and histology. The ECTI was readily visible in MPAM-SHGM and quantitative shape analysis showed ECTI deformation in dysplasia but not in normal mucosa. ΔLinearity was significantly (p normal (0.11±0.04) as measured in MPAM-SHGM and results were confirmed in histology which showed similar trends in ΔLinearity. Increase in ΔLinearity was also statistically significant for different grades of dysplasia. In-vivo ΔLinearity measurement alone from microscopy discriminated dysplasia from normal tissue with 87.9% sensitivity and 97.6% specificity, while calculations from histology provided 96.4% sensitivity and 85.7% specificity. Among other quantifiable architectural changes, a progressive statistically significant increase in epithelial thickness was seen with increasing grade of dysplasia. MPAM-SHGM provides new noninvasive ways for direct characterization of ECTI which may be used in preclinical studies to investigate the role of this interface in early transformation. Further development of the

  1. Cardiac Myocyte Diversity and a Fibroblast Network in the Junctional Region of the Zebrafish Heart Revealed by Transmission and Serial Block-Face Scanning Electron Microscopy

    KAUST Repository

    Lafontant, Pascal J.

    2013-08-23

    The zebrafish has emerged as an important model of heart development and regeneration. While the structural characteristics of the developing and adult zebrafish ventricle have been previously studied, little attention has been paid to the nature of the interface between the compact and spongy myocardium. Here we describe how these two distinct layers are structurally and functionally integrated. We demonstrate by transmission electron microscopy that this interface is complex and composed primarily of a junctional region occupied by collagen, as well as a population of fibroblasts that form a highly complex network. We also describe a continuum of uniquely flattened transitional cardiac myocytes that form a circumferential plate upon which the radially-oriented luminal trabeculae are anchored. In addition, we have uncovered within the transitional ring a subpopulation of markedly electron dense cardiac myocytes. At discrete intervals the transitional cardiac myocytes form contact bridges across the junctional space that are stabilized through localized desmosomes and fascia adherentes junctions with adjacent compact cardiac myocytes. Finally using serial block-face scanning electron microscopy, segmentation and volume reconstruction, we confirm the three-dimensional nature of the junctional region as well as the presence of the sheet-like fibroblast network. These ultrastructural studies demonstrate the previously unrecognized complexity with which the compact and spongy layers are structurally integrated, and provide a new basis for understanding development and regeneration in the zebrafish heart. © 2013 Lafontant et al.

  2. Alfalfa Root Growth Rate Correlates with Progression of Microtubules during Mitosis and Cytokinesis as Revealed by Environmental Light-Sheet Microscopy.

    Science.gov (United States)

    Vyplelová, Petra; Ovečka, Miroslav; Šamaj, Jozef

    2017-01-01

    Cell division and expansion are two fundamental biological processes supporting indeterminate root growth and development of plants. Quantitative evaluations of cell divisions related to root growth analyses have been performed in several model crop and non-crop plant species, but not in important legume plant Medicago sativa. Light-sheet fluorescence microscopy (LSFM) is an advanced imaging technique widely used in animal developmental biology, providing efficient fast optical sectioning under physiological conditions with considerably reduced phototoxicity and photobleaching. Long-term 4D imaging of living plants offers advantages for developmental cell biology not available in other microscopy approaches. Recently, LSFM was implemented in plant developmental biology studies, however, it is largely restricted to the model plant Arabidopsis thaliana. Cellular and subcellular events in crop species and robust plant samples have not been studied by this method yet. Therefore we performed LSFM long-term live imaging of growing root tips of transgenic alfalfa plants expressing the fluorescent molecular marker for the microtubule-binding domain (GFP-MBD), in order to study dynamic patterns of microtubule arrays during mitotic cell division. Quantitative evaluations of cell division progress in the two root tissues (epidermis and cortex) clearly indicate that root growth rate is correlated with duration of cell division in alfalfa roots. Our results favor non-invasive environmental LSFM as one of the most suitable methods for qualitative and quantitative cellular and developmental imaging of living transgenic legume crops.

  3. Alfalfa Root Growth Rate Correlates with Progression of Microtubules during Mitosis and Cytokinesis as Revealed by Environmental Light-Sheet Microscopy

    Directory of Open Access Journals (Sweden)

    Petra Vyplelová

    2017-10-01

    Full Text Available Cell division and expansion are two fundamental biological processes supporting indeterminate root growth and development of plants. Quantitative evaluations of cell divisions related to root growth analyses have been performed in several model crop and non-crop plant species, but not in important legume plant Medicago sativa. Light-sheet fluorescence microscopy (LSFM is an advanced imaging technique widely used in animal developmental biology, providing efficient fast optical sectioning under physiological conditions with considerably reduced phototoxicity and photobleaching. Long-term 4D imaging of living plants offers advantages for developmental cell biology not available in other microscopy approaches. Recently, LSFM was implemented in plant developmental biology studies, however, it is largely restricted to the model plant Arabidopsis thaliana. Cellular and subcellular events in crop species and robust plant samples have not been studied by this method yet. Therefore we performed LSFM long-term live imaging of growing root tips of transgenic alfalfa plants expressing the fluorescent molecular marker for the microtubule-binding domain (GFP-MBD, in order to study dynamic patterns of microtubule arrays during mitotic cell division. Quantitative evaluations of cell division progress in the two root tissues (epidermis and cortex clearly indicate that root growth rate is correlated with duration of cell division in alfalfa roots. Our results favor non-invasive environmental LSFM as one of the most suitable methods for qualitative and quantitative cellular and developmental imaging of living transgenic legume crops.

  4. New method for visualization of silica phytoliths in Sorghum bicolor roots by fluorescence microscopy revealed silicate concentration-dependent phytolith formation.

    Science.gov (United States)

    Soukup, Milan; Martinka, Michal; Cigáň, Marek; Ravaszová, Frederika; Lux, Alexander

    2014-12-01

    Silica phytoliths are microscopic structures of amorphous hydrated silica (SiO2 · nH2O) formed by specialized plant cells. Besides their biological roles, physical, chemical, and structural properties of biogenic silica offer a wide spectrum of applications in many fields of industry and technology. Therefore, processes involved in their formation recently become a very interesting topic to study. However, optical transparency and microscopic sizes of silica phytoliths do not allow their visualization and localization by classical light microscopy methods. Their observation thus requires phytolith isolation, technically difficult or lengthy sample preparation procedures, or a work with toxic chemicals. In this paper we are proposing a novel method for visualization of silica phytoliths in Sorghum bicolor root endodermal cells by fluorescence microscopy using alkali mounting solution (pH 12). This method offers an easy and quick preparation of the samples and high contrast imaging. Based on our results we can assume that the proposed fluorescent method for silica phytolith investigation allows observation of multiple samples in relatively short time period and thus might be applicable also for high-throughput screenings. Using this method we found out that after a 3-day cultivation of sorghum plants the minimal needed concentration of sodium silicate, limiting the formation of silica phytoliths in the root endodermis, was 25 µmol dm(-3). The positive correlation of sodium silicate concentration in the substrate with the phytolith diameter was also observed.

  5. PCR reveals significantly higher rates of Trypanosoma cruzi infection than microscopy in the Chagas vector, Triatoma infestans: High rates found in Chuquisaca, Bolivia

    Directory of Open Access Journals (Sweden)

    Lucero David E

    2007-06-01

    ' and TCZ2 (5' – CCT CCA AGC AGC GGA TAG TTC AGG – 3' primers. Amplicons were chromatographed on a 2% agarose gel with a 100 bp size standard, stained with ethidium bromide and viewed with UV fluorescence. For both the microscopy and PCR assays, we calculated sensitivity (number of positives by a method divided by the number of positives by either method and discrepancy (one method was negative and the other was positive at the locality, life stage and habitat level. The degree of agreement between PCR and microscopy was determined by calculating Kappa (k values with 95% confidence intervals. Results We observed a high prevalence of T. cruzi infection in T. infestans (81.16% by PCR and 56.52% by microscopy and discovered that PCR is significantly more sensitive than microscopic observation. The overall degree of agreement between the two methods was moderate (Kappa = 0.43 ± 0.07. The level of infection is significantly different among communities; however, prevalence was similar among habitats and life stages. Conclusion PCR was significantly more sensitive than microscopy in all habitats, developmental stages and localities in Chuquisaca, Bolivia. Overall we observed a high prevalence of T. cruzi infection in T. infestans in this area of Bolivia; however, microscopy underestimated infection at all levels examined.

  6. Video Podcasts

    DEFF Research Database (Denmark)

    Nortvig, Anne Mette; Sørensen, Birgitte Holm

    2016-01-01

    This project’s aim was to support and facilitate master’s students’ preparation and collaboration by making video podcasts of short lectures available on YouTube prior to students’ first face-to-face seminar. The empirical material stems from group interviews, from statistical data created through...... YouTube analytics and from surveys answered by students after the seminar. The project sought to explore how video podcasts support learning and reflection online and how students use and reflect on the integration of online activities in the videos. Findings showed that students engaged actively...

  7. Acoustic microscopy

    CERN Document Server

    Briggs, Andrew

    2010-01-01

    For many years 'Acoustic Microscopy' has been the definitive book on the subject. A key development since it was first published has been the development of ultrasonic force microscopy. This edition has a major new chapter on this technique and its applications.

  8. Super-resolution 2-photon microscopy reveals that the morphology of each dendritic spine correlates with diffusive but not synaptic properties

    Directory of Open Access Journals (Sweden)

    Kevin eTakasaki

    2014-05-01

    Full Text Available The structure of dendritic spines suggests a specialized function in compartmentalizing synaptic signals near active synapses. Indeed, theoretical and experimental analyses indicate that the diffusive resistance of the spine neck is sufficient to effectively compartmentalize some signaling molecules in a spine for the duration of their activated lifetime. Here we describe the application of 2-photon microscopy combined with stimulated emission depletion (STED-2P to the biophysical study of the relationship between synaptic signals and spine morphology, demonstrating the utility of combining STED-2P with modern optical and electrophysiological techniques. Morphological determinants of fluorescence recovery time were identified and evaluated within the context of a simple compartmental model describing diffusive transfer between spine and dendrite. Correlations between the neck geometry and the amplitude of synapse potentials and calcium transients evoked by 2-photon glutamate uncaging were also investigated.

  9. Time-resolved microscopy reveals the driving mechanism of particle formation during ultrashort pulse laser ablation of dentin-like ivory

    Science.gov (United States)

    Domke, Matthias; Gavrilova, Anna; Rapp, Stephan; Frentzen, Matthias; Meister, Joerg; Huber, Heinz P.

    2015-07-01

    In dental health care, the application of ultrashort laser pulses enables dental tissue ablation free from thermal side effects, such as melting and cracking. However, these laser types create undesired micro- and nanoparticles, which might cause a health risk for the patient or surgeon. The aim of this study was to investigate the driving mechanisms of micro- and nanoparticle formation during ultrashort pulse laser ablation of dental tissue. Time-resolved microscopy was chosen to observe the ablation dynamics of mammoth ivory after irradiation with 660 fs laser pulses. The results suggest that nanoparticles might arise in the excited region. The thermal expansion of the excited material induces high pressure in the surrounding bulk tissue, generating a pressure wave. The rarefaction wave behind this pressure wave causes spallation, leading to ejection of microparticles.

  10. Pore networks and polymer rearrangement on a drug-eluting stent as revealed by correlated confocal Raman and atomic force microscopy.

    Science.gov (United States)

    Biggs, Kevin B; Balss, Karin M; Maryanoff, Cynthia A

    2012-05-29

    Drug release from and coating morphology on a CYPHER sirolimus-eluting coronary stent (SES) during in vitro elution were studied by correlated confocal Raman and atomic force microscopy (CRM and AFM, respectively). Chemical surface and subsurface maps of the SES were generated in the same region of interest by CRM and were correlated with surface topography measured by AFM at different elution times. For the first time, a direct correlation between drug-rich regions and the coating morphology was made on a drug-eluting medical device, linking drug release with pore formation, pore throats, and pore networks. Drug release was studied on a drug-eluting stent (DES) system with a multicomponent carrier matrix (poly(n-butyl methacrylate) [PBMA] and poly(ethylene-co-vinyl acetate) [PEVA]). The polymer was found to rearrange postelution because confluence of the carrier polymer matrix reconstituted the voids created by drug release.

  11. Relationships of Trichomonas gallinae to the palatal-esophageal junction of ring doves (Streptopelia risoria) as revealed by scanning electron microscopy.

    Science.gov (United States)

    Kietzmann, G E

    1993-06-01

    Ring doves (Streptopelia risoria) were experimentally infected with pathogenic (virulent) Trichomonas gallinae so that trichomonad activities in the upper alimentary tract, prior to canker formation, could be examined with scanning electron microscopy. Between 6 and 15 hr postinoculation low numbers of ameboid T. gallinae were attached to apical microfolds and cell borders of the palatal-esophageal junction squamous epithelium. Initial parasite activities at tightly attached cell borders and apical microfolds suggest that some parasite-secreted factor or factors initiated squamous cell damage, separation, and removal. As squamous cell borders separated, trichomonads invaded areas beneath them and ultimately aided in their complete removal. Accelerated parasite-mediated desquamation, the invasion of increased mucosal surface area by trichomonads, and the eruption and expansion of cankers were the primary changes to the palatal-esophageal junction and other upper alimentary tract tissues that occurred between 19 and 240 hr postinoculation.

  12. Cortical actin nodes: Their dynamics and recruitment of podosomal proteins as revealed by super-resolution and single-molecule microscopy

    Science.gov (United States)

    Shirai, Yuki M.; Tsunoyama, Taka A.; Hiramoto-Yamaki, Nao; Hirosawa, Koichiro M.; Shibata, Akihiro C. E.; Kondo, Kenichi; Tsurumune, Atsushi; Ishidate, Fumiyoshi; Kusumi, Akihiro

    2017-01-01

    Electron tomography of the plasma membrane (PM) identified several layers of cortical actin meshwork running parallel to the PM cytoplasmic surface throughout the PM. Here, cortical actin structures and dynamics were examined in living cells, using super-resolution microscopy, with (x,y)- and z-resolutions of ~140 and ~400 nm, respectively, and single-molecule imaging. The super-resolution microscopy identified sub-micron-sized actin clusters that appeared identical by both phalloidin post-fixation staining and Lifeact-mGFP expression followed by fixation, and therefore, these actin clusters were named “actin-pl-clusters”. In live cells, the actin-pl-clusters visualized by Lifeact-mGFP linked two or more actin filaments in the fine actin meshwork, acting as a node of the meshwork, and dynamically moved on/along the meshwork in a myosin II-dependent manner. Their formation depended on the Arp2/3 activities, suggesting that the movements could involve both the myosin motor activity and actin polymerization-depolymerization. The actin-pl-clusters differ from the actin nodes/asters found previously after latrunculin treatments, since myosin II and filamin A were not colocalized with the actin-pl-clusters, and the actin-pl-clusters were much smaller than the previously reported nodes/asters. The Lifeact linked to a fluorescently-labeled transmembrane peptide from syntaxin4 (Lifeact-TM) expressed in the PM exhibited temporary immobilization in the PM regions on which actin-pl-clusters and stress fibers were projected, showing that ≥66% of actin-pl-clusters and 89% of stress fibers were located in close proximity (within 3.5 nm) to the PM cytoplasmic surface. Podosome-associated cytoplasmic proteins, Tks4, Tks5, cortactin, and N-WASP, were transiently recruited to actin-pl-clusters, and thus, we propose that actin-pl-clusters also represent “actin podosome-like clusters”. PMID:29190677

  13. X-ray and Cryo-electron Microscopy Structures of Monalysin Pore-forming Toxin Reveal Multimerization of the Pro-form.

    Science.gov (United States)

    Leone, Philippe; Bebeacua, Cecilia; Opota, Onya; Kellenberger, Christine; Klaholz, Bruno; Orlov, Igor; Cambillau, Christian; Lemaitre, Bruno; Roussel, Alain

    2015-05-22

    β-Barrel pore-forming toxins (β-PFT), a large family of bacterial toxins, are generally secreted as water-soluble monomers and can form oligomeric pores in membranes following proteolytic cleavage and interaction with cell surface receptors. Monalysin has been recently identified as a β-PFT that contributes to the virulence of Pseudomonas entomophila against Drosophila. It is secreted as a pro-protein that becomes active upon cleavage. Here we report the crystal and cryo-electron microscopy structure of the pro-form of Monalysin as well as the crystal structures of the cleaved form and of an inactive mutant lacking the membrane-spanning region. The overall structure of Monalysin displays an elongated shape, which resembles those of β-pore-forming toxins, such as Aerolysin, but is devoid of a receptor-binding domain. X-ray crystallography, cryo-electron microscopy, and light-scattering studies show that pro-Monalysin forms a stable doughnut-like 18-mer complex composed of two disk-shaped nonamers held together by N-terminal swapping of the pro-peptides. This observation is in contrast with the monomeric pro-form of the other β-PFTs that are receptor-dependent for membrane interaction. The membrane-spanning region of pro-Monalysin is fully buried in the center of the doughnut, suggesting that upon cleavage of pro-peptides, the two disk-shaped nonamers can, and have to, dissociate to leave the transmembrane segments free to deploy and lead to pore formation. In contrast with other toxins, the delivery of 18 subunits at once, nearby the cell surface, may be used to bypass the requirement of receptor-dependent concentration to reach the threshold for oligomerization into the pore-forming complex. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  14. Nanoscale Phase-Separated Structure in Core-Shell Nanoparticles of SiO2-Si1-xGexO2 Glass Revealed by Electron Microscopy.

    Science.gov (United States)

    Kubo, Yugo; Yonezawa, Kazuhiro

    2017-09-05

    SiO2-based optical fibers are indispensable components of modern information communication technologies. It has recently become increasingly important to establish a technique for visualizing the nanoscale phase-separated structure inside SiO2-GeO2 glass nanoparticles during the manufacturing of SiO2-GeO2 fibers. This is because the rapidly increasing price of Ge has made it necessary to improve the Ge yield by clarifying the detailed mechanism of Ge diffusion into SiO2. However, direct observation of the internal nanostructure of glass particles has been extremely difficult, mainly due to electrostatic charging and the damage induced by electron and X-ray irradiation. In the present study, we used state-of-the-art scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), and energy dispersive X-ray spectroscopy (EDX) to examine cross-sectional samples of SiO2-GeO2 particles embedded in an epoxy resin, which were fabricated using a broad Ar ion beam and a focused Ga ion beam. These advanced techniques enabled us to observe the internal phase-separated structure of the nanoparticles. We have for the first time clearly determined the SiO2-Si1-xGexO2 core-shell structure of such particles, the element distribution, the degree of crystallinity, and the quantitative chemical composition of microscopic regions, and we discuss the formation mechanism for the observed structure. The proposed imaging protocol is highly promising for studying the internal structure of various core-shell nanoparticles, which affects their catalytic, optical, and electronic properties.

  15. Revealing the synergetic effects in Ni nanoparticle-carbon nanotube hybrids by scanning transmission X-ray microscopy and their application in the hydrolysis of ammonia borane

    Science.gov (United States)

    Zhao, Guanqi; Zhong, Jun; Wang, Jian; Sham, Tsun-Kong; Sun, Xuhui; Lee, Shuit-Tong

    2015-05-01

    The hybrids of carbon nanotubes (CNTs) and the supported Ni nanoparticles (NPs) have been studied by scanning transmission X-ray microscopy (STXM) and tested by the hydrolysis reaction of ammonia borane (AB, NH3BH3). Data clearly showed the existence of a strong interaction between Ni NPs and thin CNTs (C-O-Ni bonds), which favored the tunable (buffer) electronic structure of Ni NPs facilitating the catalytic process. The hydrolysis process of AB confirmed the hypothesis that the hybrids with a strong interfacial interaction would show superior catalytic performance, while the hybrids with a weak interfacial interaction show poor performance. Our results provide a wealth of detailed information regarding the electronic structure of the NP-CNT hybrids and provide guidance towards the rational design of high-performance catalysts for energy applications.The hybrids of carbon nanotubes (CNTs) and the supported Ni nanoparticles (NPs) have been studied by scanning transmission X-ray microscopy (STXM) and tested by the hydrolysis reaction of ammonia borane (AB, NH3BH3). Data clearly showed the existence of a strong interaction between Ni NPs and thin CNTs (C-O-Ni bonds), which favored the tunable (buffer) electronic structure of Ni NPs facilitating the catalytic process. The hydrolysis process of AB confirmed the hypothesis that the hybrids with a strong interfacial interaction would show superior catalytic performance, while the hybrids with a weak interfacial interaction show poor performance. Our results provide a wealth of detailed information regarding the electronic structure of the NP-CNT hybrids and provide guidance towards the rational design of high-performance catalysts for energy applications. Electronic supplementary information (ESI) available: Magnified TEM images, high resolution TEM images and the particle size distributions of the samples, the STXM results of a thick tube at different positions, XPS results, stability test. See DOI: 10.1039/c5nr01168j

  16. Single Particle Electron Microscopy Analysis of the Bovine Anion Exchanger 1 Reveals a Flexible Linker Connecting the Cytoplasmic and Membrane Domains

    Science.gov (United States)

    Abuladze, Natalia; Atanasov, Ivo; Ge, Peng; Narla, Mohandas; Pushkin, Alexander; Zhou, Z. Hong; Kurtz, Ira

    2013-01-01

    Anion exchanger 1 (AE1) is the major erythrocyte membrane protein that mediates chloride/bicarbonate exchange across the erythrocyte membrane facilitating CO2 transport by the blood, and anchors the plasma membrane to the spectrin-based cytoskeleton. This multi-protein cytoskeletal complex plays an important role in erythrocyte elasticity and membrane stability. An in-frame AE1 deletion of nine amino acids in the cytoplasmic domain in a proximity to the membrane domain results in a marked increase in membrane rigidity and ovalocytic red cells in the disease Southeast Asian Ovalocytosis (SAO). We hypothesized that AE1 has a flexible region connecting the cytoplasmic and membrane domains, which is partially deleted in SAO, thus causing the loss of erythrocyte elasticity. To explore this hypothesis, we developed a new non-denaturing method of AE1 purification from bovine erythrocyte membranes. A three-dimensional (3D) structure of bovine AE1 at 2.4 nm resolution was obtained by negative staining electron microscopy, orthogonal tilt reconstruction and single particle analysis. The cytoplasmic and membrane domains are connected by two parallel linkers. Image classification demonstrated substantial flexibility in the linker region. We propose a mechanism whereby flexibility of the linker region plays a critical role in regulating red cell elasticity. PMID:23393575

  17. Single particle electron microscopy analysis of the bovine anion exchanger 1 reveals a flexible linker connecting the cytoplasmic and membrane domains.

    Directory of Open Access Journals (Sweden)

    Jiansen Jiang

    Full Text Available Anion exchanger 1 (AE1 is the major erythrocyte membrane protein that mediates chloride/bicarbonate exchange across the erythrocyte membrane facilitating CO₂ transport by the blood, and anchors the plasma membrane to the spectrin-based cytoskeleton. This multi-protein cytoskeletal complex plays an important role in erythrocyte elasticity and membrane stability. An in-frame AE1 deletion of nine amino acids in the cytoplasmic domain in a proximity to the membrane domain results in a marked increase in membrane rigidity and ovalocytic red cells in the disease Southeast Asian Ovalocytosis (SAO. We hypothesized that AE1 has a flexible region connecting the cytoplasmic and membrane domains, which is partially deleted in SAO, thus causing the loss of erythrocyte elasticity. To explore this hypothesis, we developed a new non-denaturing method of AE1 purification from bovine erythrocyte membranes. A three-dimensional (3D structure of bovine AE1 at 2.4 nm resolution was obtained by negative staining electron microscopy, orthogonal tilt reconstruction and single particle analysis. The cytoplasmic and membrane domains are connected by two parallel linkers. Image classification demonstrated substantial flexibility in the linker region. We propose a mechanism whereby flexibility of the linker region plays a critical role in regulating red cell elasticity.

  18. The origin of bimodal luminescence of β-SiAlON:Eu{sup 2+} phosphors as revealed by fluorescence microscopy and cathodoluminescence analysis

    Energy Technology Data Exchange (ETDEWEB)

    Gan, Lin [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Mao, Zhi-Yong [University of Chinese Academy of Sciences, Beijing 100049 (China); Inorganic Coating Materials Research Center, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Zeng, Xiong-Hui [Electron Microscope Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123 (China); Zhang, Yu-Qiang [The Research Center of Structural Ceramic Engineering, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Zhao, Yang [University of Chinese Academy of Sciences, Beijing 100049 (China); Inorganic Coating Materials Research Center, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Xu, Fang-Fang, E-mail: ffxu@mail.sic.ac.cn [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Zhu, Ying-Chun [Inorganic Coating Materials Research Center, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Liu, Xue-Jian [Electron Microscope Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123 (China)

    2014-03-01

    Graphical abstract: - Highlights: • Bimodal emission is originated from β-SiAlON grains with z ≥ 2. • Coexistence of two kinds of emission centers in the β-SiAlON phase is definite. • Fluorescence microscopy shows influence of the z value on emission of β-SiAlON. - Abstract: Eu{sup 2+}-doped SiAlON phosphors with the composition of Eu{sub x}Si{sub 6−z}Al{sub z}O{sub z}N{sub 8−z} (0.5 ≤ z ≤ 3) at a fixed x = 0.01 were synthesized by the gas pressure sintering method. Dependence of luminescence properties on the phase compositions in β-SiAlON:Eu{sup 2+} phosphors has been examined via fluorescence microscope and scanning electron microscope equipped with a cathodoluminescence spectrometer and an energy dispersive spectrometer. Bimodal emission (green and violet) from β-SiAlON phase is observed in the samples with z ≥ 2, indicating co-existence of two different kinds of coordination for Eu{sup 2+} ions in the host lattice.

  19. X-Ray Crystallography and Electron Microscopy of Cross- and Multi-Module Nonribosomal Peptide Synthetase Proteins Reveal a Flexible Architecture.

    Science.gov (United States)

    Tarry, Michael J; Haque, Asfarul S; Bui, Khanh Huy; Schmeing, T Martin

    2017-05-02

    Nonribosomal peptide synthetases (NRPS) are macromolecular machines that produce peptides with diverse activities. Structural information exists for domains, didomains, and even modules, but little is known about higher-order organization. We performed a multi-technique study on constructs from the dimodular NRPS DhbF. We determined a crystal structure of a cross-module construct including the adenylation (A) and peptidyl carrier protein (PCP) domains from module 1 and the condensation domain from module 2, complexed with an adenosine-vinylsulfonamide inhibitor and an MbtH-like protein (MLP). The action of the inhibitor and the role of the MLP were investigated using adenylation reactions and isothermal titration calorimetry. In the structure, the PCP and A domains adopt a novel conformation, and noncovalent, cross-module interactions are limited. We calculated envelopes of dimodular DhbF using negative-stain electron microscopy. The data show large conformational variability between modules. Together, our results suggest that NRPSs lack a uniform, rigid supermodular architecture. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Spectral force analysis using atomic force microscopy reveals the importance of surface heterogeneity in bacterial and colloid adhesion to engineered surfaces.

    Science.gov (United States)

    Ma, Huilian; Winslow, Charles J; Logan, Bruce E

    2008-04-01

    Coatings developed to reduce biofouling of engineered surfaces do not always perform as expected based on their native properties. One reason is that a relatively small number of highly adhesive sites, or the heterogeneity of the coated surface, may control the overall response of the system to initial bacterial deposition. It is shown here using an approach we call spectral force analysis (SFA), based on force volume imaging of the surface with atomic force microscopy, that the behavior of surfaces and coatings can be better understood relative to bacterial adhesion. The application of vapor deposited TiO(2) metal oxide increased bacterial and colloid adhesion, but coating the surface with silica oxide reduced adhesion in a manner consistent with SFA based on analysis of the "stickiest" sites. Application of a TiO(2)-based paint to a surface produced a relatively non-fouling surface. Addition of a hydrophilic layer coating to this surface should have decreased fouling. However, it was observed that this coating actually increased fouling. Using SFA it was shown that the reason for the increased adhesion of bacteria and particles to the hydrophilic layer was that the surface produced by this coating was highly heterogeneous, resulting in a small number of sites that created a stickier surface. These results show that while it is important to manufacture surfaces with coatings that are relatively non-adhesive to bacteria, it is also essential that these coatings have a highly uniform surface chemistry.

  1. Structural variability and complexity of the giant Pithovirus sibericum particle revealed by high-voltage electron cryo-tomography and energy-filtered electron cryo-microscopy.

    Science.gov (United States)

    Okamoto, Kenta; Miyazaki, Naoyuki; Song, Chihong; Maia, Filipe R N C; Reddy, Hemanth K N; Abergel, Chantal; Claverie, Jean-Michel; Hajdu, Janos; Svenda, Martin; Murata, Kazuyoshi

    2017-10-16

    The Pithoviridae giant virus family exhibits the largest viral particle known so far, a prolate spheroid up to 2.5 μm in length and 0.9 μm in diameter. These particles show significant variations in size. Little is known about the structure of the intact virion due to technical limitations with conventional electron cryo-microscopy (cryo-EM) when imaging thick specimens. Here we present the intact structure of the giant Pithovirus sibericum particle at near native conditions using high-voltage electron cryo-tomography (cryo-ET) and energy-filtered cryo-EM. We detected a previously undescribed low-density outer layer covering the tegument and a periodical structuring of the fibres in the striated apical cork. Energy-filtered Zernike phase-contrast cryo-EM images show distinct substructures inside the particles, implicating an internal compartmentalisation. The density of the interior volume of Pithovirus particles is three quarters lower than that of the Mimivirus. However, it is remarkably high given that the 600 kbp Pithovirus genome is only half the size of the Mimivirus genome and is packaged in a volume up to 100 times larger. These observations suggest that the interior is densely packed with macromolecules in addition to the genomic nucleic acid.

  2. Changes in hemp secondary fiber production related to technical fiber variability revealed by light microscopy and attenuated total reflectance Fourier transform infrared spectroscopy.

    Science.gov (United States)

    Fernandez-Tendero, Eva; Day, Arnaud; Legros, Sandrine; Habrant, Anouck; Hawkins, Simon; Chabbert, Brigitte

    2017-01-01

    Interest in hemp (Cannabis sativa L.) is increasing due to the development of a new range of industrial applications based on bast fibers. However the variability of bast fiber yield and quality represents an important barrier to further exploitation. Primary and secondary fiber content was examined in two commercial hemp varieties (Fedora 17, Santhica 27) grown under contrasted sowing density and irrigation conditions. Both growing conditions and hemp varieties impact stem tissue architecture with a large effect on the proportion of secondary fibers but not primary fibers. Attenuated total reflectance infrared spectroscopy allowed the discrimination of manually-isolated native primary fibers and secondary fibers but did not reveal any clustering according to growing conditions and variety. Infrared data were confirmed by wet chemistry analyses that revealed slight but significant differences between primary and secondary fiber cell wall composition. Infrared spectroscopy of technical fibers obtained after mechanical defibering revealed differences with native primary, but not secondary fibers and also discriminated samples obtained from plants grown under different conditions. Altogether the results suggested that the observed variability of hemp technical fibers could be partially explained by i) differences in secondary fiber production and ii) differential behavior during mechanical defibering resulting in unequal separation of primary and secondary fibers.

  3. Correlative microscopy.

    Science.gov (United States)

    Loussert Fonta, Céline; Humbel, Bruno M

    2015-09-01

    In recent years correlative microscopy, combining the power and advantages of different imaging system, e.g., light, electrons, X-ray, NMR, etc., has become an important tool for biomedical research. Among all the possible combinations of techniques, light and electron microscopy, have made an especially big step forward and are being implemented in more and more research labs. Electron microscopy profits from the high spatial resolution, the direct recognition of the cellular ultrastructure and identification of the organelles. It, however, has two severe limitations: the restricted field of view and the fact that no live imaging can be done. On the other hand light microscopy has the advantage of live imaging, following a fluorescently tagged molecule in real time and at lower magnifications the large field of view facilitates the identification and location of sparse individual cells in a large context, e.g., tissue. The combination of these two imaging techniques appears to be a valuable approach to dissect biological events at a submicrometer level. Light microscopy can be used to follow a labelled protein of interest, or a visible organelle such as mitochondria, in time, then the sample is fixed and the exactly same region is investigated by electron microscopy. The time resolution is dependent on the speed of penetration and fixation when chemical fixatives are used and on the reaction time of the operator for cryo-fixation. Light microscopy can also be used to identify cells of interest, e.g., a special cell type in tissue or cells that have been modified by either transfections or RNAi, in a large population of non-modified cells. A further application is to find fluorescence labels in cells on a large section to reduce searching time in the electron microscope. Multiple fluorescence labelling of a series of sections can be correlated with the ultrastructure of the individual sections to get 3D information of the distribution of the marked proteins: array

  4. ASYMMETRY OF EYESPOT AND MATING STRUCTURE POSITIONS IN ULVA COMPRESSA (ULVALES, CHLOROPHYTA) REVEALED BY A NEW FIELD EMISSION SCANNING ELECTRON MICROSCOPY METHOD(1).

    Science.gov (United States)

    Mogi, Yuko; Kagami, Yayoi; Kuwano, Kazuyoshi; Miyamura, Shinichi; Nagumo, Tamotsu; Kawano, Shigeyuki

    2008-10-01

    Gametes of the marine green alga Ulva compressa L. are biflagellate and pear shaped, with one eyespot at the posterior end of the cell. The species is at an early evolutionary stage between isogamy and anisogamy. In the past, zygote formation of green algae was categorized solely by the relative sizes of gametes produced by two mating types (+ and -). Recently, however, locations of cell fusion sites and/or mating structures of gametes have been observed to differ between mating types in several green algae (asymmetry of cell fusion site and/or mating structure positions). To use this asymmetry for determining gamete mating type, we explored a new method, field emission scanning electron microscopy (FE-SEM), for visualizing the mating structure of U. compressa. When gametes were subjected to drying stress in the process of a conventional critical-point-drying method, a round structure was observed on the cell surfaces. In the mating type MGEC-1 (mt(+) ), this structure was located on the same side of the cell as the eyespot, whereas it was on the side opposite the eyespot in the mating type MGEC-2 (mt(-) ). The gametes fuse at the round structures. TEM showed an alignment of vesicles inside the cytoplasm directly below the round structures, which are indeed the mating structures. Serial sectioning and three-dimensional construction of TEM micrographs confirmed the association of the mating structure with flagellar roots. The mating structure was associated with 1d root in the MGEC-1 gamete but with 2d root in the MGEC-2 gamete. © 2008 Phycological Society of America.

  5. Cryo-electron microscopy structures of the SARS-CoV spike glycoprotein reveal a prerequisite conformational state for receptor binding.

    Science.gov (United States)

    Gui, Miao; Song, Wenfei; Zhou, Haixia; Xu, Jingwei; Chen, Silian; Xiang, Ye; Wang, Xinquan

    2017-01-01

    The global outbreak of SARS in 2002-2003 was caused by the infection of a new human coronavirus SARS-CoV. The infection of SARS-CoV is mediated mainly through the viral surface glycoproteins, which consist of S1 and S2 subunits and form trimer spikes on the envelope of the virions. Here we report the ectodomain structures of the SARS-CoV surface spike trimer in different conformational states determined by single-particle cryo-electron microscopy. The conformation 1 determined at 4.3 Å resolution is three-fold symmetric and has all the three receptor-binding C-terminal domain 1 (CTD1s) of the S1 subunits in "down" positions. The binding of the "down" CTD1s to the SARS-CoV receptor ACE2 is not possible due to steric clashes, suggesting that the conformation 1 represents a receptor-binding inactive state. Conformations 2-4 determined at 7.3, 5.7 and 6.8 Å resolutions are all asymmetric, in which one RBD rotates away from the "down" position by different angles to an "up" position. The "up" CTD1 exposes the receptor-binding site for ACE2 engagement, suggesting that the conformations 2-4 represent a receptor-binding active state. This conformational change is also required for the binding of SARS-CoV neutralizing antibodies targeting the CTD1. This phenomenon could be extended to other betacoronaviruses utilizing CTD1 of the S1 subunit for receptor binding, which provides new insights into the intermediate states of coronavirus pre-fusion spike trimer during infection.

  6. Noncytopathic hepatitis A virus induces surface alterations in LLC-MK2 cells revealed by thin sections, negative staining, and scanning electron microscopy

    Directory of Open Access Journals (Sweden)

    Francisco Hernández-Chavarría

    2002-06-01

    Full Text Available Previous electron microscope studies of ultrastructural events during hepatitis A virus replication in experimentally infected cells have used only ultrathin section techniques. Nevertheless, no important differences were observed between infected and uninfected cells. This study was carried out using scanning electron microscopy and negative staining of whole LLC-MK2 cells grown directly on grids covered with support membranes, and then infected with an hepatitis A virus strain. Thin sections of infected and unifected controls were also analyzed. An intricate web of projections forming a net between cell interfaces was observed only in infected cells. Some of these projections were more than 700 nm long and had ballooning tips. Nevertheless, HAV particles were not visualized in the infected cellsLos estudios previos sobre los eventos ultraestructurales en la replicación del virus de la hepatitis Aen cultivos de células infectadas experimentalmente, se han realizado exclusivamente mediante cortes ultrafinos. No obstante, no se han observado diferencias importantes entre células infectadas y no infectadas. Este estudio fue realizado empleando microscopia electrónica de rastreo, tinción negativa de células (LLC-MK2 cultivadas directamente sobre rejillas para microscopia electrónica de transmisión e infectadas con el virus de la hepatitis A. Adicionalmente se analizaron cortes ultrafinos de células infectadas y no infectadas. Se observó una intrincada red de proyecciones entre las superficies de las células, que apareció solo en las células infectadas. Algunas de esas proyecciones medían más de 700 nm de largo y terminaban en extremos abultados. Sin embargo, no se observaron viriones en las células infectadas

  7. Akademisk video

    DEFF Research Database (Denmark)

    Frølunde, Lisbeth

    2017-01-01

    Dette kapitel har fokus på metodiske problemstillinger, der opstår i forhold til at bruge (digital) video i forbindelse med forskningskommunikation, ikke mindst online. Video har længe været benyttet i forskningen til dataindsamling og forskningskommunikation. Med digitaliseringen og internettet er...... der dog opstået nye muligheder og udfordringer i forhold til at formidle og distribuere forskningsresultater til forskellige målgrupper via video. Samtidig er klassiske metodologiske problematikker som forskerens positionering i forhold til det undersøgte stadig aktuelle. Både klassiske og nye...... problemstillinger diskuteres i kapitlet, som rammesætter diskussionen ud fra forskellige positioneringsmuligheder: formidler, historiefortæller, eller dialogist. Disse positioner relaterer sig til genrer inden for ’akademisk video’. Afslutningsvis præsenteres en metodisk værktøjskasse med redskaber til planlægning...

  8. A video rate laser scanning confocal microscope

    Science.gov (United States)

    Ma, Hongzhou; Jiang, James; Ren, Hongwu; Cable, Alex E.

    2008-02-01

    A video-rate laser scanning microscope was developed as an imaging engine to integrate with other photonic building blocks to fulfill various microscopic imaging applications. The system is quipped with diode laser source, resonant scanner, galvo scanner, control electronic and computer loaded with data acquisition boards and imaging software. Based on an open frame design, the system can be combined with varies optics to perform the functions of fluorescence confocal microscopy, multi-photon microscopy and backscattering confocal microscopy. Mounted to the camera port, it allows a traditional microscope to obtain confocal images at video rate. In this paper, we will describe the design principle and demonstrate examples of applications.

  9. Video Analytics

    DEFF Research Database (Denmark)

    This book collects the papers presented at two workshops during the 23rd International Conference on Pattern Recognition (ICPR): the Third Workshop on Video Analytics for Audience Measurement (VAAM) and the Second International Workshop on Face and Facial Expression Recognition (FFER) from Real...... World Videos. The workshops were run on December 4, 2016, in Cancun in Mexico. The two workshops together received 13 papers. Each paper was then reviewed by at least two expert reviewers in the field. In all, 11 papers were accepted to be presented at the workshops. The topics covered in the papers...

  10. Sub-nanometer surface chemistry and orbital hybridization in lanthanum-doped ceria nano-catalysts revealed by 3D electron microscopy.

    Science.gov (United States)

    Collins, Sean M; Fernandez-Garcia, Susana; Calvino, José J; Midgley, Paul A

    2017-07-14

    Surface chemical composition, electronic structure, and bonding characteristics determine catalytic activity but are not resolved for individual catalyst particles by conventional spectroscopy. In particular, the nano-scale three-dimensional distribution of aliovalent lanthanide dopants in ceria catalysts and their effect on the surface electronic structure remains unclear. Here, we reveal the surface segregation of dopant cations and oxygen vacancies and observe bonding changes in lanthanum-doped ceria catalyst particle aggregates with sub-nanometer precision using a new model-based spectroscopic tomography approach. These findings refine our understanding of the spatially varying electronic structure and bonding in ceria-based nanoparticle aggregates with aliovalent cation concentrations and identify new strategies for advancing high efficiency doped ceria nano-catalysts.

  11. Video Analytics

    DEFF Research Database (Denmark)

    This book collects the papers presented at two workshops during the 23rd International Conference on Pattern Recognition (ICPR): the Third Workshop on Video Analytics for Audience Measurement (VAAM) and the Second International Workshop on Face and Facial Expression Recognition (FFER) from Real W...

  12. Second harmonic generation microscopy

    DEFF Research Database (Denmark)

    Brüggemann, Dagmar Adeline; Brewer, Jonathan R.; Risbo, Jens

    2010-01-01

    -temperature endotherm peak observable in the differential scanning calorimetry (DSC) thermograms. DSC analysis of epimysium, the connective tissue layer that enfold skeletal muscles, produces one large endotherm starting at 57 °C and peaking at 59.5 °C. SHG microscopy of collagen fibers reveals a variability of thermal...

  13. Confocal microscopy

    Indian Academy of Sciences (India)

    molecular aggregates in artificial light harvesting sys- tem it is important to elucidate the exciton dynamics of individual micro-rods which can be achieved by using confocal microscopy and polarization resolved single molecule fluorescence spectroscopy.30 41 In the present work, we have studied exciton dynamics of two.

  14. Video Analytics

    DEFF Research Database (Denmark)

    This book collects the papers presented at two workshops during the 23rd International Conference on Pattern Recognition (ICPR): the Third Workshop on Video Analytics for Audience Measurement (VAAM) and the Second International Workshop on Face and Facial Expression Recognition (FFER) from Real...... include: re-identification, consumer behavior analysis, utilizing pupillary response for task difficulty measurement, logo detection, saliency prediction, classification of facial expressions, face recognition, face verification, age estimation, super-resolution, pose estimation, and pain recognition...

  15. Video Analytics

    DEFF Research Database (Denmark)

    include: re-identification, consumer behavior analysis, utilizing pupillary response for task difficulty measurement, logo detection, saliency prediction, classification of facial expressions, face recognition, face verification, age estimation, super-resolution, pose estimation, and pain recognition......This book collects the papers presented at two workshops during the 23rd International Conference on Pattern Recognition (ICPR): the Third Workshop on Video Analytics for Audience Measurement (VAAM) and the Second International Workshop on Face and Facial Expression Recognition (FFER) from Real...

  16. The effects of video game play on the characteristics of saccadic eye movements

    National Research Council Canada - National Science Library

    Mack, David J; Ilg, Uwe J

    2014-01-01

    Video game play has become a common leisure activity all around the world. To reveal possible effects of playing video games, we measured saccades elicited by video game players (VGPs) and non-players (NVGPs...

  17. The phase transformation of methane caused by pressure change during its rise from the seafloor revealed by video observation and acoustic reflection data

    Science.gov (United States)

    Aoyama, C.

    2013-12-01

    Acoustic reflection depending on physical property differences among solid of methane hydrates and methane gas bubbles from seafloor and sea water.By sending ultrasonic waves from the transducer of an echo sounder or a sonar system through the water and measuring the echo of the back-scatterings from the methane hydrates or bubbles,it is possible that a visualized image of the methane plumes is displayed on the display of an echo sounder or a sonar system.Estimates of the amount of the methane plumes are extremely important for the global environment as part of the carbon cycle.The observations were carried out at Umitaka Spur and Joetsu knoll in the Sea of Japan every year since 2004. There are many methane plumes in the same ocean area. Thus, we investigate minutely about methane plumes in this study.In order to recognize estimates of the methane plumes, we observed the image of methane plumes using a remotely operated submarine vehicle (Hyper Dolphin, of the Japan Agency of Marine-Earth Science and Technology (JAMSTEC)), and captured the methane bubble using a funnel.We observe the images of the methane plumes seeping points on the seafloor taken by a high-definition camera loaded in the vehicle, measure the surfacing velocity of the gushed methane plumes, and compute the surfacing velocity of the gas and solid substance using a theoretical formula.The observation was carried out at Umitaka Spur in the Japan Sea. The depth was 1000 m and the seawater temperature was 0.3 C°.From 3 seeping points, we gathered 300ml of methane in 643 seconds in the funnel with an opening of 20 cm in diameter.If it is assumed that the seeping points are equally scattered in the area, the seeping volume per unit area is 5.4×104cm3 per hour, which is 4.7×102m3 per year.The experiment in the ocean revealed the followings.The methane hydrate particles that are seeping out from seafloor are solid substances just above the seafloor.In the studied ocean area, 7.7×104m3 of methane

  18. Video Malware - Behavioral Analysis

    Directory of Open Access Journals (Sweden)

    Rajdeepsinh Dodia

    2015-04-01

    Full Text Available Abstract The counts of malware attacks exploiting the internet increasing day by day and has become a serious threat. The latest malware spreading out through the media players embedded using the video clip of funny in nature to lure the end users. Once it is executed and installed then the behavior of the malware is in the malware authors hand. The spread of the malware emulates through Internet USB drives sharing of the files and folders can be anything which makes presence concealed. The funny video named as it connected to the film celebrity where the malware variant was collected from the laptop of the terror outfit organization .It runs in the backend which it contains malicious code which steals the user sensitive information like banking credentials username amp password and send it to the remote host user called command amp control. The stealed data is directed to the email encapsulated in the malicious code. The potential malware will spread through the USB and other devices .In summary the analysis reveals the presence of malicious code in executable video file and its behavior.

  19. Using Video Clips To Teach Social Psychology.

    Science.gov (United States)

    Roskos-Ewoldsen, David R.; Roskos-Ewoldsen, Beverly

    2001-01-01

    Explores the effectiveness of using short video clips from feature films to highlight theoretical concepts when teaching social psychology. Reveals that short video clips have many of the same advantages as showing full-length films and demonstrates that students saw the use of these clips as an effective tool. (CMK)

  20. Diogenes, Dogfaced Soldiers, and Deployment Music Videos

    Science.gov (United States)

    Carter, Geoffrey; Williamson, Bill

    2010-01-01

    This webtext explores the cynical/kynical humor of soldier videos, suggesting that amateur videos paradoxically both undercut authority and honor effective leaders, both make light of and also publicly reveal deployment hardships, both distance the performers from military groupthink and celebrate unit camaraderie.

  1. Advantages of Live Microscope Video for Laboratory and Teaching Applications

    Science.gov (United States)

    Michels, Kristin K.; Michels, Zachary D.; Hotchkiss, Sara C.

    2016-01-01

    Although spatial reasoning and penetrative thinking skills are essential for many disciplines, these concepts are difficult for students to comprehend. In microscopy, traditional educational materials (i.e., photographs) are static. Conversely, video-based training methods convey dimensionality. We implemented a real-time digital video imaging…

  2. NEI You Tube Videos: Amblyopia

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    Full Text Available ... NEI YouTube Videos > NEI YouTube Videos: Amblyopia NEI YouTube Videos YouTube Videos Home Age-Related Macular Degeneration ... Retinopathy of Prematurity Science Spanish Videos Webinars NEI YouTube Videos: Amblyopia Embedded video for NEI YouTube Videos: ...

  3. NEI You Tube Videos: Amblyopia

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    Full Text Available ... YouTube Videos > NEI YouTube Videos: Amblyopia NEI YouTube Videos YouTube Videos Home Age-Related Macular Degeneration Amblyopia ... of Prematurity Science Spanish Videos Webinars NEI YouTube Videos: Amblyopia Embedded video for NEI YouTube Videos: Amblyopia ...

  4. NEI You Tube Videos: Amblyopia

    Science.gov (United States)

    ... YouTube Videos > NEI YouTube Videos: Amblyopia NEI YouTube Videos YouTube Videos Home Age-Related Macular Degeneration Amblyopia ... of Prematurity Science Spanish Videos Webinars NEI YouTube Videos: Amblyopia Embedded video for NEI YouTube Videos: Amblyopia ...

  5. Video Game Training and the Reward System

    Directory of Open Access Journals (Sweden)

    Robert C. Lorenz

    2015-02-01

    Full Text Available Video games contain elaborate reinforcement and reward schedules that have the potential to maximize motivation. Neuroimaging studies suggest that video games might have an influence on the reward system. However, it is not clear whether reward-related properties represent a precondition, which biases an individual towards playing video games, or if these changes are the result of playing video games. Therefore, we conducted a longitudinal study to explore reward-related functional predictors in relation to video gaming experience as well as functional changes in the brain in response to video game training.Fifty healthy participants were randomly assigned to a video game training (TG or control group (CG. Before and after training/control period, functional magnetic resonance imaging (fMRI was conducted using a non-video game related reward task.At pretest, both groups showed strongest activation in ventral striatum (VS during reward anticipation. At posttest, the TG showed very similar VS activity compared to pretest. In the CG, the VS activity was significantly attenuated.This longitudinal study revealed that video game training may preserve reward responsiveness in the ventral striatum in a retest situation over time. We suggest that video games are able to keep striatal responses to reward flexible, a mechanism which might be of critical value for applications such as therapeutic cognitive training.

  6. Video game training and the reward system.

    Science.gov (United States)

    Lorenz, Robert C; Gleich, Tobias; Gallinat, Jürgen; Kühn, Simone

    2015-01-01

    Video games contain elaborate reinforcement and reward schedules that have the potential to maximize motivation. Neuroimaging studies suggest that video games might have an influence on the reward system. However, it is not clear whether reward-related properties represent a precondition, which biases an individual toward playing video games, or if these changes are the result of playing video games. Therefore, we conducted a longitudinal study to explore reward-related functional predictors in relation to video gaming experience as well as functional changes in the brain in response to video game training. Fifty healthy participants were randomly assigned to a video game training (TG) or control group (CG). Before and after training/control period, functional magnetic resonance imaging (fMRI) was conducted using a non-video game related reward task. At pretest, both groups showed strongest activation in ventral striatum (VS) during reward anticipation. At posttest, the TG showed very similar VS activity compared to pretest. In the CG, the VS activity was significantly attenuated. This longitudinal study revealed that video game training may preserve reward responsiveness in the VS in a retest situation over time. We suggest that video games are able to keep striatal responses to reward flexible, a mechanism which might be of critical value for applications such as therapeutic cognitive training.

  7. Rheumatoid Arthritis Educational Video Series

    Medline Plus

    Full Text Available ... Rheumatoid Arthritis Educational Video Series Rheumatoid Arthritis Educational Video Series This series of five videos was designed ... Activity Role of Body Weight in Osteoarthritis Educational Videos for Patients Rheumatoid Arthritis Educational Video Series Psoriatic ...

  8. Spatial light interference microscopy (SLIM).

    Science.gov (United States)

    Wang, Zhuo; Millet, Larry; Mir, Mustafa; Ding, Huafeng; Unarunotai, Sakulsuk; Rogers, John; Gillette, Martha U; Popescu, Gabriel

    2011-01-17

    We present spatial light interference microscopy (SLIM) as a new optical microscopy technique, capable of measuring nanoscale structures and dynamics in live cells via interferometry. SLIM combines two classic ideas in light imaging: Zernike's phase contrast microscopy, which renders high contrast intensity images of transparent specimens, and Gabor's holography, where the phase information from the object is recorded. Thus, SLIM reveals the intrinsic contrast of cell structures and, in addition, renders quantitative optical path-length maps across the sample. The resulting topographic accuracy is comparable to that of atomic force microscopy, while the acquisition speed is 1,000 times higher. We illustrate the novel insight into cell dynamics via SLIM by experiments on primary cell cultures from the rat brain. SLIM is implemented as an add-on module to an existing phase contrast microscope, which may prove instrumental in impacting the light microscopy field at a large scale.

  9. Multimodal hyperspectral optical microscopy

    Science.gov (United States)

    Novikova, Irina V.; Smallwood, Chuck R.; Gong, Yu; Hu, Dehong; Hendricks, Leif; Evans, James E.; Bhattarai, Ashish; Hess, Wayne P.; El-Khoury, Patrick Z.

    2017-11-01

    We describe a unique approach to hyperspectral optical microscopy, herein achieved by coupling a hyperspectral imager to various optical microscopes. Hyperspectral fluorescence micrographs of isolated fluorescent beads are first employed to ensure spectral calibration of our detector and to gauge the attainable spatial resolution of our measurements. Different science applications of our instrument are then described. Spatially over-sampled absorption spectroscopy of a single lipid (18:1 Liss Rhod PE) layer reveals that optical densities on the order of 10-3 can be resolved by spatially averaging the recorded optical signatures. This is followed by three applications in the general areas of plasmonics and bioimaging. Notably, we deploy hyperspectral absorption microscopy to identify and image pigments within a simple biological system, namely, a single live Tisochrysis lutea cell. Overall, this work paves the way for multimodal spectral imaging measurements spanning the realms of several scientific disciplines.

  10. Video Design Games

    DEFF Research Database (Denmark)

    Smith, Rachel Charlotte; Christensen, Kasper Skov; Iversen, Ole Sejer

    We introduce Video Design Games to train educators in teaching design. The Video Design Game is a workshop format consisting of three rounds in which participants observe, reflect and generalize based on video snippets from their own practice. The paper reports on a Video Design Game workshop...

  11. Characterization of social video

    Science.gov (United States)

    Ostrowski, Jeffrey R.; Sarhan, Nabil J.

    2009-01-01

    The popularity of social media has grown dramatically over the World Wide Web. In this paper, we analyze the video popularity distribution of well-known social video websites (YouTube, Google Video, and the AOL Truveo Video Search engine) and characterize their workload. We identify trends in the categories, lengths, and formats of those videos, as well as characterize the evolution of those videos over time. We further provide an extensive analysis and comparison of video content amongst the main regions of the world.

  12. Video Games: Play That Can Do Serious Good

    National Research Council Canada - National Science Library

    Adam Eichenbaum; Daphne Bavelier; C Shawn Green

    2014-01-01

      The authors review recent research that reveals how today's video games instantiate naturally and effectively many principles psychologists, neuroscientists, and educators believe critical for learning...

  13. Video visual analytics

    OpenAIRE

    Höferlin, Markus Johannes

    2013-01-01

    The amount of video data recorded world-wide is tremendously growing and has already reached hardly manageable dimensions. It originates from a wide range of application areas, such as surveillance, sports analysis, scientific video analysis, surgery documentation, and entertainment, and its analysis represents one of the challenges in computer science. The vast amount of video data renders manual analysis by watching the video data impractical. However, automatic evaluation of video material...

  14. Influence of the hydrostatic pulpal pressure on droplets formation in current etch-and-rinse and self-etch adhesives: a video rate/TSM microscopy and fluid filtration study.

    Science.gov (United States)

    Sauro, Salvatore; Mannocci, Francesco; Toledano, Manuel; Osorio, Raquel; Thompson, Ian; Watson, Timothy F

    2009-11-01

    The aim of this study was to investigate the droplet formation using a real-time/confocal microscopy technique, when different self-etching and etch-and-rinse adhesives were applied in the presence or absence of pulpal pressure. Resin-dentin permeability (%P) was also evaluated. Optibond FL, Silorane adhesive, Scotchbond 1XT, G-Bond and DC-Bond were bonded in the presence or in absence of simulated pulpal pressure. A fluid-transport model was used to measure the water permeability through resin-bonded dentin. Half of the specimens bonded in the presence of the hydrostatic pulpal pressure (20 cm H2O) were light cured, whereas the remnant half received no light curing. The same was done with the half of the specimens bonded under no pulpal pressure. The specimens were investigated under a confocal TSM. Optibond FL and G-Bond had the lowest dentin permeability. Optibond FL adhesive showed few water droplets on the polymerized external surface and within the resin-dentin interface. G-Bond showed static interfacial globular-like droplet formation. DC-Bond and Scotchbond 1XT were the most water permeable adhesives both in the presence and in absence of pulpal pressure. A dynamic interfacial non-globular-like droplet formation was observed. Severe droplet formation was observed on the polymerized external surface. The presence of the pulpal pressure may cause increasing in fluid filtration and droplet formation in simplified adhesives containing HEMA. The adhesives containing 4-META (G-Bond) may be affected by static phase separation but by very low osmotic droplets formation and water permeability. The three-step adhesives are less affected by these problems.

  15. Viewers Motivations for Watching Beauty Videos on You Tube

    OpenAIRE

    Jiroušková, Dominika

    2016-01-01

    The diploma thesis focuses on motivations for watching beauty videos on YouTube. The aim is to clarify why viewers watch amateur videos that communicate topics related to physical appearance. Assuming the audience as an active actor of media communication the thesis is based on uses and gratification theory. Viewers watch beauty videos consciously to meet their individual needs. Based on an analysis of eleven interviews with regular viewers of beauty videos this thesis reveals five categories...

  16. Electron microscopy of viruses.

    Science.gov (United States)

    Laue, Michael

    2010-01-01

    Electron microscopy is widely used in virology because viruses are generally too small for a direct inspection by light microscopy. Analysis of virus morphology is necessary in many circumstances, e.g., for the diagnosis of a virus in particular clinical situations or the analysis of virus entry and assembly. Moreover, quality control of virus particle integrity is required if a virus is propagated in cell culture, particularly if the virus genome has changed. In most cases already the basic methodology for transmission electron microscopy, i.e., negative staining and ultrathin sectioning, is sufficient to give relevant information on virus ultrastructure. This chapter gives detailed information on the principles of these basic methodologies and provides simple but reliable protocols for a quick start. Moreover, the description of standard protocols for negative staining and ultrathin sectioning are supplemented by protocols on immuno-negative staining and rapid ultrathin sectioning. Finally, principles of methods for an extended ultrastructural research using more elaborate techniques, such as cryotechniques or methods to reveal the three-dimensional virus architecture, are briefly reviewed. Copyright © 2010 Elsevier Inc. All rights reserved.

  17. TEM Video Compressive Sensing

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, Andrew; Kovarik, Libor; Abellan, Patricia; Yuan, Xin; Carin, Lawrence; Browning, Nigel D.

    2015-08-01

    One of the main limitations of imaging at high spatial and temporal resolution during in-situ TEM experiments is the frame rate of the camera being used to image the dynamic process. While the recent development of direct detectors has provided the hardware to achieve frame rates approaching 0.1ms, the cameras are expensive and must replace existing detectors. In this paper, we examine the use of coded aperture compressive sensing methods [1, 2, 3, 4] to increase the framerate of any camera with simple, low-cost hardware modifications. The coded aperture approach allows multiple sub-frames to be coded and integrated into a single camera frame during the acquisition process, and then extracted upon readout using statistical compressive sensing inversion. Our simulations show that it should be possible to increase the speed of any camera by at least an order of magnitude. Compressive Sensing (CS) combines sensing and compression in one operation, and thus provides an approach that could further improve the temporal resolution while correspondingly reducing the electron dose rate. Because the signal is measured in a compressive manner, fewer total measurements are required. When applied to TEM video capture, compressive imaging couled improve acquisition speed and reduce the electron dose rate. CS is a recent concept, and has come to the forefront due the seminal work of Candès [5]. Since the publication of Candès, there has been enormous growth in the application of CS and development of CS variants. For electron microscopy applications, the concept of CS has also been recently applied to electron tomography [6], and reduction of electron dose in scanning transmission electron microscopy (STEM) imaging [7]. To demonstrate the applicability of coded aperture CS video reconstruction for atomic level imaging, we simulate compressive sensing on observations of Pd nanoparticles and Ag nanoparticles during exposure to high temperatures and other environmental conditions

  18. Playing violent video games increases intergroup bias.

    Science.gov (United States)

    Greitemeyer, Tobias

    2014-01-01

    Previous research has shown how, why, and for whom violent video game play is related to aggression and aggression-related variables. In contrast, less is known about whether some individuals are more likely than others to be the target of increased aggression after violent video game play. The present research examined the idea that the effects of violent video game play are stronger when the target is a member of an outgroup rather than an ingroup. In fact, a correlational study revealed that violent video game exposure was positively related to ethnocentrism. This relation remained significant when controlling for trait aggression. Providing causal evidence, an experimental study showed that playing a violent video game increased aggressive behavior, and that this effect was more pronounced when the target was an outgroup rather than an ingroup member. Possible mediating mechanisms are discussed.

  19. Cell Phone Video Recording Feature as a Language Learning Tool: A Case Study

    Science.gov (United States)

    Gromik, Nicolas A.

    2012-01-01

    This paper reports on a case study conducted at a Japanese national university. Nine participants used the video recording feature on their cell phones to produce weekly video productions. The task required that participants produce one 30-second video on a teacher-selected topic. Observations revealed the process of video creation with a cell…

  20. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... support group for me? Find a Group Upcoming Events Video Library Photo Gallery One-on-One Support ... group for me? Find a group Back Upcoming events Video Library Photo Gallery One-on-One Support ...

  1. Video Games and Citizenship

    National Research Council Canada - National Science Library

    Bourgonjon, Jeroen; Soetaert, Ronald

    2013-01-01

    ... by exploring a particular aspect of digitization that affects young people, namely video games. They explore the new social spaces which emerge in video game culture and how these spaces relate to community building and citizenship...

  2. Videos, Podcasts and Livechats

    Medline Plus

    Full Text Available ... Doctor Find a Provider Meet the Team Blog Articles News Resources Links Videos Podcasts Webinars For the ... Doctor Find a Provider Meet the Team Blog Articles News Provider Directory Donate Resources Links Videos Podcasts ...

  3. Videos, Podcasts and Livechats

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    Full Text Available ... Doctor Find a Provider Meet the Team Blog Articles & Stories News Resources Links Videos Podcasts Webinars For ... Doctor Find a Provider Meet the Team Blog Articles & Stories News Provider Directory Donate Resources Links Videos ...

  4. Digital Video in Research

    DEFF Research Database (Denmark)

    Frølunde, Lisbeth

    2012-01-01

    questions of our media literacy pertaining to authoring multimodal texts (visual, verbal, audial, etc.) in research practice and the status of multimodal texts in academia. The implications of academic video extend to wider issues of how researchers harness opportunities to author different types of texts......Is video becoming “the new black” in academia, if so, what are the challenges? The integration of video in research methodology (for collection, analysis) is well-known, but the use of “academic video” for dissemination is relatively new (Eriksson and Sørensen). The focus of this paper is academic...... video, or short video essays produced for the explicit purpose of communicating research processes, topics, and research-based knowledge (see the journal of academic videos: www.audiovisualthinking.org). Video is increasingly used in popular showcases for video online, such as YouTube and Vimeo, as well...

  5. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... Back Support Groups Is a support group for me? Find a Group Upcoming Events Video Library Photo ... Support Groups Back Is a support group for me? Find a group Back Upcoming events Video Library ...

  6. Acoustic Neuroma Educational Video

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  7. Videos, Podcasts and Livechats

    Medline Plus

    Full Text Available ... the Team Blog Articles & Stories News Resources Links Videos Podcasts Webinars For the Media For Clinicians For ... Family Caregivers Glossary Menu In this section Links Videos Podcasts Webinars For the Media For Clinicians For ...

  8. Videos, Podcasts and Livechats

    Science.gov (United States)

    ... the Team Blog Articles & Stories News Resources Links Videos Podcasts Webinars For the Media For Clinicians For ... Family Caregivers Glossary Menu In this section Links Videos Podcasts Webinars For the Media For Clinicians For ...

  9. Videos, Podcasts and Livechats

    Medline Plus

    Full Text Available ... a Provider Meet the Team Blog Articles & Stories News Resources Links Videos Podcasts Webinars For the Media ... a Provider Meet the Team Blog Articles & Stories News Provider Directory Donate Resources Links Videos Podcasts Webinars ...

  10. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... for me? Find a Group Upcoming Events Video Library Photo Gallery One-on-One Support ANetwork Peer ... me? Find a group Back Upcoming events Video Library Photo Gallery One-on-One Support Back ANetwork ...

  11. Video Screen Capture Basics

    Science.gov (United States)

    Dunbar, Laura

    2014-01-01

    This article is an introduction to video screen capture. Basic information of two software programs, QuickTime for Mac and BlueBerry Flashback Express for PC, are also discussed. Practical applications for video screen capture are given.

  12. Videos, Podcasts and Livechats

    Medline Plus

    Full Text Available ... News Resources Links Videos Podcasts Webinars For the Media For Clinicians For Policymakers For Family Caregivers Glossary ... this section Links Videos Podcasts Webinars For the Media For Clinicians For Policymakers For Family Caregivers Glossary ...

  13. Transmission of compressed video

    Science.gov (United States)

    Pasch, H. L.

    1990-09-01

    An overview of video coding is presented. The aim is not to give a technical summary of possible coding techniques, but to address subjects related to video compression in general and to the transmission of compressed video in more detail. Bit rate reduction is in general possible by removing redundant information; removing information the eye does not use anyway; and reducing the quality of the video. The codecs which are used for reducing the bit rate, can be divided into two groups: Constant Bit rate Codecs (CBC's), which keep the bit rate constant, but vary the video quality; and Variable Bit rate Codecs (VBC's), which keep the video quality constant by varying the bit rate. VBC's can be in general reach a higher video quality than CBC's using less bandwidth, but need a transmission system that allows the bandwidth of a connection to fluctuate in time. The current and the next generation of the PSTN does not allow this; ATM might. There are several factors which influence the quality of video: the bit error rate of the transmission channel, slip rate, packet loss rate/packet insertion rate, end-to-end delay, phase shift between voice and video, and bit rate. Based on the bit rate of the coded video, the following classification of coded video can be made: High Definition Television (HDTV); Broadcast Quality Television (BQTV); video conferencing; and video telephony. The properties of these classes are given. The video conferencing and video telephony equipment available now and in the next few years can be divided into three categories: conforming to 1984 CCITT standard for video conferencing; conforming to 1988 CCITT standard; and conforming to no standard.

  14. Making good physics videos

    Science.gov (United States)

    Lincoln, James

    2017-05-01

    Online videos are an increasingly important way technology is contributing to the improvement of physics teaching. Students and teachers have begun to rely on online videos to provide them with content knowledge and instructional strategies. Online audiences are expecting greater production value, and departments are sometimes requesting educators to post video pre-labs or to flip our classrooms. In this article, I share my advice on creating engaging physics videos.

  15. Desktop video conferencing

    OpenAIRE

    Potter, Ray; Roberts, Deborah

    2007-01-01

    This guide aims to provide an introduction to Desktop Video Conferencing. You may be familiar with video conferencing, where participants typically book a designated conference room and communicate with another group in a similar room on another site via a large screen display. Desktop video conferencing (DVC), as the name suggests, allows users to video conference from the comfort of their own office, workplace or home via a desktop/laptop Personal Computer. DVC provides live audio and visua...

  16. 47 CFR 79.3 - Video description of video programming.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Video description of video programming. 79.3... CLOSED CAPTIONING AND VIDEO DESCRIPTION OF VIDEO PROGRAMMING § 79.3 Video description of video programming. (a) Definitions. For purposes of this section the following definitions shall apply: (1...

  17. Video Self-Modeling

    Science.gov (United States)

    Buggey, Tom; Ogle, Lindsey

    2012-01-01

    Video self-modeling (VSM) first appeared on the psychology and education stage in the early 1970s. The practical applications of VSM were limited by lack of access to tools for editing video, which is necessary for almost all self-modeling videos. Thus, VSM remained in the research domain until the advent of camcorders and VCR/DVD players and,…

  18. Tracing Sequential Video Production

    DEFF Research Database (Denmark)

    Otrel-Cass, Kathrin; Khalid, Md. Saifuddin

    2015-01-01

    With an interest in learning that is set in collaborative situations, the data session presents excerpts from video data produced by two of fifteen students from a class of 5th semester techno-anthropology course. Students used video cameras to capture the time they spent working with a scientist...... video, nature of the interactional space, and material and spatial semiotics....

  19. Developing a Promotional Video

    Science.gov (United States)

    Epley, Hannah K.

    2014-01-01

    There is a need for Extension professionals to show clientele the benefits of their program. This article shares how promotional videos are one way of reaching audiences online. An example is given on how a promotional video has been used and developed using iMovie software. Tips are offered for how professionals can create a promotional video and…

  20. Advanced video coding systems

    CERN Document Server

    Gao, Wen

    2015-01-01

    This comprehensive and accessible text/reference presents an overview of the state of the art in video coding technology. Specifically, the book introduces the tools of the AVS2 standard, describing how AVS2 can help to achieve a significant improvement in coding efficiency for future video networks and applications by incorporating smarter coding tools such as scene video coding. Topics and features: introduces the basic concepts in video coding, and presents a short history of video coding technology and standards; reviews the coding framework, main coding tools, and syntax structure of AV

  1. Intelligent video surveillance systems

    CERN Document Server

    Dufour, Jean-Yves

    2012-01-01

    Belonging to the wider academic field of computer vision, video analytics has aroused a phenomenal surge of interest since the current millennium. Video analytics is intended to solve the problem of the incapability of exploiting video streams in real time for the purpose of detection or anticipation. It involves analyzing the videos using algorithms that detect and track objects of interest over time and that indicate the presence of events or suspect behavior involving these objects.The aims of this book are to highlight the operational attempts of video analytics, to identify possi

  2. VBR video traffic models

    CERN Document Server

    Tanwir, Savera

    2014-01-01

    There has been a phenomenal growth in video applications over the past few years. An accurate traffic model of Variable Bit Rate (VBR) video is necessary for performance evaluation of a network design and for generating synthetic traffic that can be used for benchmarking a network. A large number of models for VBR video traffic have been proposed in the literature for different types of video in the past 20 years. Here, the authors have classified and surveyed these models and have also evaluated the models for H.264 AVC and MVC encoded video and discussed their findings.

  3. Multimodal hyperspectral optical microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Novikova, Irina V.; Smallwood, Chuck R.; Gong, Yu; Hu, Dehong; Hendricks, Leif; Evans, James E.; Bhattarai, Ashish; Hess, Wayne P.; El-Khoury, Patrick Z.

    2017-09-01

    We describe a unique and convenient approach to multimodal hyperspectral optical microscopy, herein achieved by coupling a portable and transferable hyperspectral imager to various optical microscopes. The experimental and data analysis schemes involved in recording spectrally and spatially resolved fluorescence, dark field, and optical absorption micrographs are illustrated through prototypical measurements targeting selected model systems. Namely, hyperspectral fluorescence micrographs of isolated fluorescent beads are employed to ensure spectral calibration of our detector and to gauge the attainable spatial resolution of our measurements; the recorded images are diffraction-limited. Moreover, spatially over-sampled absorption spectroscopy of a single lipid (18:1 Liss Rhod PE) layer reveals that optical densities on the order of 10-3 may be resolved by spatially averaging the recorded optical signatures. We also briefly illustrate two applications of our setup in the general areas of plasmonics and cell biology. Most notably, we deploy hyperspectral optical absorption microscopy to identify and image algal pigments within a single live Tisochrysis lutea cell. Overall, this work paves the way for multimodal multidimensional spectral imaging measurements spanning the realms of several scientific disciples.

  4. Flip Video for Dummies

    CERN Document Server

    Hutsko, Joe

    2010-01-01

    The full-color guide to shooting great video with the Flip Video camera. The inexpensive Flip Video camera is currently one of the hottest must-have gadgets. It's portable and connects easily to any computer to transfer video you shoot onto your PC or Mac. Although the Flip Video camera comes with a quick-start guide, it lacks a how-to manual, and this full-color book fills that void! Packed with full-color screen shots throughout, Flip Video For Dummies shows you how to shoot the best possible footage in a variety of situations. You'll learn how to transfer video to your computer and then edi

  5. Analysis of cell dispersion and migration by video-microscopy.

    Science.gov (United States)

    Bonnomet, Arnaud; Terryn, Christine; Cutrona, Jérôme; Jonquet, Antoine; Birembaut, Philippe; Zahm, Jean-Marie

    2012-01-01

    In different physiopathological situations such as embryogenesis, wound repair and tumor invasion, isolated cells, or cell populations exhibit changes to their normal behavior and may acquire different migratory phenotypes. Live-cell imaging associated with the use of appropriate in vitro models in culture has become a powerful analytical tool for studying factors involved in cell migration and in cell-to-cell interactions. The scope of this chapter is to give an overview of in vitro models of cell migration and the technical advances permitting multiparameter quantification. The chapter hereby provides a detailed description of two-dimensional and three-dimensional approaches of cell dispersion and migration and finally gives a brief insight on computational quantification of the cell behavior. Copyright © 2012 Elsevier Inc. All rights reserved.

  6. Video Object Tracking in Neural Axons with Fluorescence Microscopy Images

    Directory of Open Access Journals (Sweden)

    Liang Yuan

    2014-01-01

    tracking. In this paper, we describe two automated tracking methods for analyzing neurofilament movement based on two different techniques: constrained particle filtering and tracking-by-detection. First, we introduce the constrained particle filtering approach. In this approach, the orientation and position of a particle are constrained by the axon’s shape such that fewer particles are necessary for tracking neurofilament movement than object tracking techniques based on generic particle filtering. Secondly, a tracking-by-detection approach to neurofilament tracking is presented. For this approach, the axon is decomposed into blocks, and the blocks encompassing the moving neurofilaments are detected by graph labeling using Markov random field. Finally, we compare two tracking methods by performing tracking experiments on real time-lapse image sequences of neurofilament movement, and the experimental results show that both methods demonstrate good performance in comparison with the existing approaches, and the tracking accuracy of the tracing-by-detection approach is slightly better between the two.

  7. Flow Electrification in Nonaqueous Colloidal Suspensions, studied with Video Microscopy

    NARCIS (Netherlands)

    Tolpekin, V.A.; van den Ende, Henricus T.M.; Duits, Michael H.G.; Mellema, J.

    2004-01-01

    Flow electrification in nonaqueous suspensions has been scarcely reported in the literature but can significantly affect colloidal stability and (phase) behavior, perhaps even without being recognized. We have observed it in shear flow experiments on concentrated binary suspensions of hydrophobized

  8. Understanding Video Games

    DEFF Research Database (Denmark)

    Heide Smith, Jonas; Tosca, Susana Pajares; Egenfeldt-Nielsen, Simon

    From Pong to PlayStation 3 and beyond, Understanding Video Games is the first general introduction to the exciting new field of video game studies. This textbook traces the history of video games, introduces the major theories used to analyze games such as ludology and narratology, reviews...... the economics of the game industry, examines the aesthetics of game design, surveys the broad range of game genres, explores player culture, and addresses the major debates surrounding the medium, from educational benefits to the effects of violence. Throughout the book, the authors ask readers to consider...... larger questions about the medium: * What defines a video game? * Who plays games? * Why do we play games? * How do games affect the player? Extensively illustrated, Understanding Video Games is an indispensable and comprehensive resource for those interested in the ways video games are reshaping...

  9. Collaborative Video Sketching

    DEFF Research Database (Denmark)

    Henningsen, Birgitte; Gundersen, Peter Bukovica; Hautopp, Heidi

    2017-01-01

    This paper introduces to what we define as a collaborative video sketching process. This process links various sketching techniques with digital storytelling approaches and creative reflection processes in video productions. Traditionally, sketching has been used by designers across various...... forms and through empirical examples, we present and discuss the video recording of sketching sessions, as well as development of video sketches by rethinking, redoing and editing the recorded sessions. The empirical data is based on workshop sessions with researchers and students from universities...... and university colleges and primary and secondary school teachers. As researchers, we have had different roles in these action research case studies where various video sketching techniques were applied.The analysis illustrates that video sketching can take many forms, and two common features are important...

  10. Reflections on academic video

    Directory of Open Access Journals (Sweden)

    Thommy Eriksson

    2012-11-01

    Full Text Available As academics we study, research and teach audiovisual media, yet rarely disseminate and mediate through it. Today, developments in production technologies have enabled academic researchers to create videos and mediate audiovisually. In academia it is taken for granted that everyone can write a text. Is it now time to assume that everyone can make a video essay? Using the online journal of academic videos Audiovisual Thinking and the videos published in it as a case study, this article seeks to reflect on the emergence and legacy of academic audiovisual dissemination. Anchoring academic video and audiovisual dissemination of knowledge in two critical traditions, documentary theory and semiotics, we will argue that academic video is in fact already present in a variety of academic disciplines, and that academic audiovisual essays are bringing trends and developments that have long been part of academic discourse to their logical conclusion.

  11. Sound for digital video

    CERN Document Server

    Holman, Tomlinson

    2013-01-01

    Achieve professional quality sound on a limited budget! Harness all new, Hollywood style audio techniques to bring your independent film and video productions to the next level.In Sound for Digital Video, Second Edition industry experts Tomlinson Holman and Arthur Baum give you the tools and knowledge to apply recent advances in audio capture, video recording, editing workflow, and mixing to your own film or video with stunning results. This fresh edition is chockfull of techniques, tricks, and workflow secrets that you can apply to your own projects from preproduction

  12. Green Power Partnership Videos

    Science.gov (United States)

    The Green Power Partnership develops videos on a regular basis that explore a variety of topics including, Green Power partnership, green power purchasing, Renewable energy certificates, among others.

  13. THE EDUCATIONAL POTENTIAL OF VIDEO GAMES

    Directory of Open Access Journals (Sweden)

    Ruxandra Claudia CHIRCA (NEACȘU

    2015-11-01

    Full Text Available In nowadays' world, technological assistance is no longer confined to its primary purpose of communication or informational support and the boundaries between real and virtual world are becoming increasingly harder to be defined. This is the world of digital natives, today's children, who grow up in a technology-brimming environment and who spend most of their time playing video games. Are these video games constructive in any way? Scientific studies state they are. Video games help children in setting their goals, provide constant feedback and offer immediate rewards, along with the opportunity to collaborate with other players. Furthermore, video games can generate strong emotional reactions, such as joy or fear, and they have a captivating story line, which reveals itself within a realm of elaborate graphics.

  14. Introduction to fluorescence microscopy.

    Science.gov (United States)

    Ghiran, Ionita C

    2011-01-01

    This chapter is an overview of basic principles of fluorescence microscopy, including a brief history on the invention of this type of microscopy. The chapter highlights important points related to properties of fluorochromes, resolution in fluorescence microscopy, phase contrast and fluorescence, fluorescence filters, construction of a fluorescence microscope, and tips on the correct use of this equipment.

  15. VIDEO GAMES CONTRIBUTION TO STUDENTS’ ENTREPRENEURIAL TRAITS AND INTENT

    OpenAIRE

    Alexandra PERJU-MITRAN; Andreea E. BUDACIA

    2014-01-01

    Given the popularity of video games and the influences they may pose on individuals’ psychology and behavior, the present study analyses whether video game playing among university students can be correlated with traits associated with an entrepreneur’s profile, which may, in turn, lead to an entrepreneurial intent. The results of the study reveal that students who do play video games show a higher entrepreneurial intent, this relationship being mediated by several psychological and cognitiv...

  16. Is this charred material from a VHS video cassette?

    Science.gov (United States)

    Fruchtenicht, Tara; Blackledge, Robert D.; Williams, Teresa R.

    2010-06-01

    At his residence, a victim in a double homicide had installed a home-built video surveillance system. The suspects either knew of or discovered this system and removed it. In a backyard at a location associated with the suspects was a barrel used for burning trash. Could charred debris recovered from a metal bowl found among the contents of the barrel be the remains of a VHS video cassette? A positive answer to the question was obtained through a combination of optical microscopy, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and Energy Dispersive Spectroscopy (EDS).

  17. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... a Group Upcoming Events Video Library Photo Gallery One-on-One Support ANetwork Peer Support Program Community Connections Overview ... group Back Upcoming events Video Library Photo Gallery One-on-One Support Back ANetwork Peer Support Program ...

  18. Reviews in instructional video

    NARCIS (Netherlands)

    van der Meij, Hans

    2017-01-01

    This study investigates the effectiveness of a video tutorial for software training whose construction was based on a combination of insights from multimedia learning and Demonstration-Based Training. In the videos, a model of task performance was enhanced with instructional features that were

  19. Digital Video Editing

    Science.gov (United States)

    McConnell, Terry

    2004-01-01

    Monica Adams, head librarian at Robinson Secondary in Fairfax country, Virginia, states that librarians should have the technical knowledge to support projects related to digital video editing. The process of digital video editing and the cables, storage issues and the computer system with software is described.

  20. AudioMove Video

    DEFF Research Database (Denmark)

    2012-01-01

    Live drawing video experimenting with low tech techniques in the field of sketching and visual sense making. In collaboration with Rune Wehner and Teater Katapult.......Live drawing video experimenting with low tech techniques in the field of sketching and visual sense making. In collaboration with Rune Wehner and Teater Katapult....

  1. Making Good Physics Videos

    Science.gov (United States)

    Lincoln, James

    2017-01-01

    Online videos are an increasingly important way technology is contributing to the improvement of physics teaching. Students and teachers have begun to rely on online videos to provide them with content knowledge and instructional strategies. Online audiences are expecting greater production value, and departments are sometimes requesting educators…

  2. SECRETS OF SONG VIDEO

    Directory of Open Access Journals (Sweden)

    Chernyshov Alexander V.

    2014-04-01

    Full Text Available The article focuses on the origins of the song videos as TV and Internet-genre. In addition, it considers problems of screen images creation depending on the musical form and the text of a songs in connection with relevant principles of accent and phraseological video editing and filming techniques as well as with additional frames and sound elements.

  3. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... support group for me? Find a Group Upcoming Events Video Library Photo Gallery One-on-One Support ANetwork Peer ... group for me? Find a group Back Upcoming events Video Library Photo Gallery One-on-One Support Back ANetwork ...

  4. Personal Digital Video Stories

    DEFF Research Database (Denmark)

    Ørngreen, Rikke; Henningsen, Birgitte Sølbeck; Louw, Arnt Vestergaard

    2016-01-01

    agenda focusing on video productions in combination with digital storytelling, followed by a presentation of the digital storytelling features. The paper concludes with a suggestion to initiate research in what is identified as Personal Digital Video (PDV) Stories within longitudinal settings, while...

  5. Video game use and cognitive performance: does it vary with the presence of problematic video game use?

    Science.gov (United States)

    Collins, Emily; Freeman, Jonathan

    2014-03-01

    Action video game players have been found to outperform nonplayers on a variety of cognitive tasks. However, several failures to replicate these video game player advantages have indicated that this relationship may not be straightforward. Moreover, despite the discovery that problematic video game players do not appear to demonstrate the same superior performance as nonproblematic video game players in relation to multiple object tracking paradigms, this has not been investigated for other tasks. Consequently, this study compared gamers and nongamers in task switching ability, visual short-term memory, mental rotation, enumeration, and flanker interference, as well as investigated the influence of self-reported problematic video game use. A total of 66 participants completed the experiment, 26 of whom played action video games, including 20 problematic players. The results revealed no significant effect of playing action video games, nor any influence of problematic video game play. This indicates that the previously reported cognitive advantages in video game players may be restricted to specific task features or samples. Furthermore, problematic video game play may not have a detrimental effect on cognitive performance, although this is difficult to ascertain considering the lack of video game player advantage. More research is therefore sorely needed.

  6. Rheumatoid Arthritis Educational Video Series

    Medline Plus

    Full Text Available ... Patient Webcasts / Rheumatoid Arthritis Educational Video Series Rheumatoid Arthritis Educational Video Series This series of five videos ... member of our patient care team. Managing Your Arthritis Managing Your Arthritis Managing Chronic Pain and Depression ...

  7. Rheumatoid Arthritis Educational Video Series

    Medline Plus

    Full Text Available ... Corner / Patient Webcasts / Rheumatoid Arthritis Educational Video Series Rheumatoid Arthritis Educational Video Series This series of five videos was designed to help you learn more about Rheumatoid Arthritis (RA). You will learn how the diagnosis of ...

  8. Rheumatoid Arthritis Educational Video Series

    Science.gov (United States)

    ... Corner / Patient Webcasts / Rheumatoid Arthritis Educational Video Series Rheumatoid Arthritis Educational Video Series This series of five videos was designed to help you learn more about Rheumatoid Arthritis (RA). You will learn how the diagnosis of ...

  9. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... questions Clinical Studies Publications Catalog Photos and Images Spanish Language Information Grants and Funding Extramural Research Division ... Low Vision Refractive Errors Retinopathy of Prematurity Science Spanish Videos Webinars NEI YouTube Videos: Amblyopia Embedded video ...

  10. Structured illumination microscopy and correlative microscopy to study autophagy.

    Science.gov (United States)

    Ligeon, Laure-Anne; Barois, Nicolas; Werkmeister, Elisabeth; Bongiovanni, Antonino; Lafont, Frank

    2015-03-01

    Autophagy is a predominant eukaryotic mechanism for the engulfment of "portions" of cytoplasm allowing their degradation to recycle metabolites. The autophagy is ubiquitous among the life kingdom revealing the importance of this pathway that appears more complex than previously thought. Several reviews have already addressed how to monitor this pathway and have highlighted the existence of new routes such as the LC3-associated phagocytosis (LAP) and the non-canonical autophagy. The principal difference between autophagosomes and LAP vacuoles is that the former has two limiting membranes positives for LC3 whereas the latter has one. Herein, we propose to emphasize the use of correlative light electron microscopy (CLEM) to answer some autophagy's related questions. The structured illumination microscopy (SIM) relatively easy to implement allows to better observe the Atg proteins recruitment and localization during the autophagy process. While LC3 recruitment is performed using light microscopy the ultrastructural morphological analysis of LC3-vacuoles is ascertained by electron microscopy. Hence, these combined and correlated approaches allow to tackle the LAP vs. autophagosome issue. Copyright © 2015. Published by Elsevier Inc.

  11. A Dental Health Education Video for Nigerian Children in the ...

    African Journals Online (AJOL)

    The development of a video titled “Itoju Eyin” (meaning care of the teeth) was prompted by research findings which revealed poor oral hygiene among Nigerian children from the lower socioeconomic class. Videos have been employed as a medium of dental health education and research has shown them to be useful and ...

  12. An Update on the Effects of Playing Violent Video Games

    Science.gov (United States)

    Anderson, Craig, A.

    2004-01-01

    This article presents a brief overview of existing research on the effects of exposure to violent video games. An updated meta-analysis reveals that exposure to violent video games is significantly linked to increases in aggressive behaviour, aggressive cognition, aggressive affect, and cardiovascular arousal, and to decreases in helping…

  13. Playing Action Video Games Improves Visuomotor Control.

    Science.gov (United States)

    Li, Li; Chen, Rongrong; Chen, Jing

    2016-08-01

    Can playing action video games improve visuomotor control? If so, can these games be used in training people to perform daily visuomotor-control tasks, such as driving? We found that action gamers have better lane-keeping and visuomotor-control skills than do non-action gamers. We then trained non-action gamers with action or nonaction video games. After they played a driving or first-person-shooter video game for 5 or 10 hr, their visuomotor control improved significantly. In contrast, non-action gamers showed no such improvement after they played a nonaction video game. Our model-driven analysis revealed that although different action video games have different effects on the sensorimotor system underlying visuomotor control, action gaming in general improves the responsiveness of the sensorimotor system to input error signals. The findings support a causal link between action gaming (for as little as 5 hr) and enhancement in visuomotor control, and suggest that action video games can be beneficial training tools for driving. © The Author(s) 2016.

  14. New microscopy for nanoimaging

    CERN Document Server

    Kinjo, Y; Watanabe, M

    2002-01-01

    Two types of new microscopy, namely, X-ray contact microscopy (XRCM) in combination with atomic force microscopy (AFM) and X-ray projection microscopy (XRPM) using synchrotron radiation and zone plate optics were used to image the fine structures of human chromosomes. In the XRCM plus AFM system, location of X-ray images on a photoresist has become far easier than that with our previous method using transmission electron microscopy coupled with the replica method. In addition, the images obtained suggested that the conformation of chromatin fiber differs from the current textbook model regarding the architecture of a eukaryotic chromosome. X-ray images with high contrast of the specimens could be obtained with XRPM. The resolution of each microscopy was about 30 and 200-300 nm for XRCM plus AFM and XRPM, respectively. (author)

  15. Structural examination of lithium niobate ferroelectric crystals by combining scanning electron microscopy and atomic force microscopy

    Science.gov (United States)

    Efremova, P. V.; Ped'ko, B. B.; Kuznecova, Yu. V.

    2016-02-01

    The structure of lithium niobate single crystals is studied by a complex technique that combines scanning electron microscopy and atomic force microscopy. By implementing the piezoresponse force method on an atomic force microscope, the domain structure of lithium niobate crystals, which was not revealed without electron beam irradiation, is visualized

  16. Filter-Dense Multicolor Microscopy.

    Directory of Open Access Journals (Sweden)

    Siavash Kijani

    Full Text Available Immunofluorescence microscopy is a unique method to reveal the spatial location of proteins in tissues and cells. By combining antibodies that are labeled with different fluorochromes, the location of several proteins can simultaneously be visualized in one sample. However, because of the risk of bleed-through signals between fluorochromes, standard multicolor microscopy is restricted to a maximum of four fluorescence channels, including one for nuclei staining. This is not always enough to address common scientific questions. In particular, the use of a rapidly increasing number of marker proteins to classify functionally distinct cell populations and diseased tissues emphasizes the need for more complex multistainings. Hence, multicolor microscopy should ideally offer more channels to meet the current needs in biomedical science. Here we present an enhanced multi-fluorescence setup, which we call Filter-Dense Multicolor Microscopy (FDMM. FDMM is based on condensed filter sets that are more specific for each fluorochrome and allow a more economic use of the light spectrum. FDMM allows at least six independent fluorescence channels and can be applied to any standard fluorescence microscope without changing any operative procedures for the user. In the present study, we demonstrate an FDMM setup of six channels that includes the most commonly used fluorochromes for histology. We show that the FDMM setup is specific and robust, and we apply the technique on typical biological questions that require more than four fluorescence microscope channels.

  17. A new video programme

    CERN Multimedia

    CERN video productions

    2011-01-01

    "What's new @ CERN?", a new monthly video programme, will be broadcast on the Monday of every month on webcast.cern.ch. Aimed at the general public, the programme will cover the latest CERN news, with guests and explanatory features. Tune in on Monday 3 October at 4 pm (CET) to see the programme in English, and then at 4:20 pm (CET) for the French version.   var flash_video_player=get_video_player_path(); insert_player_for_external('Video/Public/Movies/2011/CERN-MOVIE-2011-129/CERN-MOVIE-2011-129-0753-kbps-640x360-25-fps-audio-64-kbps-44-kHz-stereo', 'mms://mediastream.cern.ch/MediaArchive/Video/Public/Movies/2011/CERN-MOVIE-2011-129/CERN-MOVIE-2011-129-Multirate-200-to-753-kbps-640x360-25-fps.wmv', 'false', 480, 360, 'https://mediastream.cern.ch/MediaArchive/Video/Public/Movies/2011/CERN-MOVIE-2011-129/CERN-MOVIE-2011-129-posterframe-640x360-at-10-percent.jpg', '1383406', true, 'Video/Public/Movies/2011/CERN-MOVIE-2011-129/CERN-MOVIE-2011-129-0600-kbps-maxH-360-25-fps-...

  18. Gamifying Video Object Segmentation.

    Science.gov (United States)

    Spampinato, Concetto; Palazzo, Simone; Giordano, Daniela

    2017-10-01

    Video object segmentation can be considered as one of the most challenging computer vision problems. Indeed, so far, no existing solution is able to effectively deal with the peculiarities of real-world videos, especially in cases of articulated motion and object occlusions; limitations that appear more evident when we compare the performance of automated methods with the human one. However, manually segmenting objects in videos is largely impractical as it requires a lot of time and concentration. To address this problem, in this paper we propose an interactive video object segmentation method, which exploits, on one hand, the capability of humans to identify correctly objects in visual scenes, and on the other hand, the collective human brainpower to solve challenging and large-scale tasks. In particular, our method relies on a game with a purpose to collect human inputs on object locations, followed by an accurate segmentation phase achieved by optimizing an energy function encoding spatial and temporal constraints between object regions as well as human-provided location priors. Performance analysis carried out on complex video benchmarks, and exploiting data provided by over 60 users, demonstrated that our method shows a better trade-off between annotation times and segmentation accuracy than interactive video annotation and automated video object segmentation approaches.

  19. Scanning ultrafast electron microscopy

    OpenAIRE

    Yang, Ding-Shyue; Mohammed, Omar F.; Zewail, Ahmed H.

    2010-01-01

    Progress has been made in the development of four-dimensional ultrafast electron microscopy, which enables space-time imaging of structural dynamics in the condensed phase. In ultrafast electron microscopy, the electrons are accelerated, typically to 200 keV, and the microscope operates in the transmission mode. Here, we report the development of scanning ultrafast electron microscopy using a field-emission-source configuration. Scanning of pulses is made in the single-electron mode, for whic...

  20. Fluorescence (Multiwave) Confocal Microscopy.

    Science.gov (United States)

    Welzel, J; Kästle, Raphaela; Sattler, Elke C

    2016-10-01

    In addition to reflectance confocal microscopy, multiwave confocal microscopes with different laser wavelengths in combination with exogenous fluorophores allow fluorescence mode confocal microscopy in vivo and ex vivo. Fluorescence mode confocal microscopy improves the contrast between the epithelium and the surrounding soft tissue and allows the depiction of certain structures, like epithelial tumors, nerves, and glands. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Interactive video algorithms and technologies

    CERN Document Server

    Hammoud, Riad

    2006-01-01

    This book covers both algorithms and technologies of interactive videos, so that businesses in IT and data managements, scientists and software engineers in video processing and computer vision, coaches and instructors that use video technology in teaching, and finally end-users will greatly benefit from it. This book contains excellent scientific contributions made by a number of pioneering scientists and experts from around the globe. It consists of five parts. The first part introduces the reader to interactive video and video summarization and presents effective methodologies for automatic abstraction of a single video sequence, a set of video sequences, and a combined audio-video sequence. In the second part, a list of advanced algorithms and methodologies for automatic and semi-automatic analysis and editing of audio-video documents are presented. The third part tackles a more challenging level of automatic video re-structuring, filtering of video stream by extracting of highlights, events, and meaningf...

  2. Electron Microscopy Center (EMC)

    Data.gov (United States)

    Federal Laboratory Consortium — The Electron Microscopy Center (EMC) at Argonne National Laboratory develops and maintains unique capabilities for electron beam characterization and applies those...

  3. Coherent light microscopy

    CERN Document Server

    Ferraro, Pietro; Zalevsky, Zeev

    2011-01-01

    This book deals with the latest achievements in the field of optical coherent microscopy. While many other books exist on microscopy and imaging, this book provides a unique resource dedicated solely to this subject. Similarly, many books describe applications of holography, interferometry and speckle to metrology but do not focus on their use for microscopy. The coherent light microscopy reference provided here does not focus on the experimental mechanics of such techniques but instead is meant to provide a users manual to illustrate the strengths and capabilities of developing techniques. Th

  4. Video-assisted lobectomy for endobronchial leiomyoma.

    LENUS (Irish Health Repository)

    Bartosik, Waldemar

    2011-02-01

    Endobronchial leiomyomas are rare tumours arising from the smooth muscle on the bronchial tree. We describe a patient with a six-month history of chest infections, who was treated surgically with a video-assisted thoracic surgery (VATS) lobectomy. The pathology revealed an endobronchial leiomyoma that coexisted with postobstructive pulmonary non-necrotising granulomas.

  5. Bridging fluorescence microscopy and electron microscopy

    NARCIS (Netherlands)

    Giepmans, Ben N. G.

    Development of new fluorescent probes and fluorescence microscopes has led to new ways to study cell biology. With the emergence of specialized microscopy units at most universities and research centers, the use of these techniques is well within reach for a broad research community. A major

  6. Categorizing Video Game Audio

    DEFF Research Database (Denmark)

    Westerberg, Andreas Rytter; Schoenau-Fog, Henrik

    2015-01-01

    This paper dives into the subject of video game audio and how it can be categorized in order to deliver a message to a player in the most precise way. A new categorization, with a new take on the diegetic spaces, can be used a tool of inspiration for sound- and game-designers to rethink how...... they can use audio in video games. The conclusion of this study is that the current models' view of the diegetic spaces, used to categorize video game audio, is not t to categorize all sounds. This can however possibly be changed though a rethinking of how the player interprets audio....

  7. Brains on video games

    OpenAIRE

    Bavelier, Daphne; Green, C. Shawn; Han, Doug Hyun; Renshaw, Perry F.; Merzenich, Michael M.; Gentile, Douglas A.

    2011-01-01

    The popular press is replete with stories about the effects of video and computer games on the brain. Sensationalist headlines claiming that video games ‘damage the brain’ or ‘boost brain power’ do not do justice to the complexities and limitations of the studies involved, and create a confusing overall picture about the effects of gaming on the brain. Here, six experts in the field shed light on our current understanding of the positive and negative ways in which playing video games can affe...

  8. High Dynamic Range Video

    CERN Document Server

    Myszkowski, Karol

    2008-01-01

    This book presents a complete pipeline forHDR image and video processing fromacquisition, through compression and quality evaluation, to display. At the HDR image and video acquisition stage specialized HDR sensors or multi-exposure techniques suitable for traditional cameras are discussed. Then, we present a practical solution for pixel values calibration in terms of photometric or radiometric quantities, which are required in some technically oriented applications. Also, we cover the problem of efficient image and video compression and encoding either for storage or transmission purposes, in

  9. 3D video

    CERN Document Server

    Lucas, Laurent; Loscos, Céline

    2013-01-01

    While 3D vision has existed for many years, the use of 3D cameras and video-based modeling by the film industry has induced an explosion of interest for 3D acquisition technology, 3D content and 3D displays. As such, 3D video has become one of the new technology trends of this century.The chapters in this book cover a large spectrum of areas connected to 3D video, which are presented both theoretically and technologically, while taking into account both physiological and perceptual aspects. Stepping away from traditional 3D vision, the authors, all currently involved in these areas, provide th

  10. Automatic inpainting scheme for video text detection and removal.

    Science.gov (United States)

    Mosleh, Ali; Bouguila, Nizar; Ben Hamza, Abdessamad

    2013-11-01

    We present a two stage framework for automatic video text removal to detect and remove embedded video texts and fill-in their remaining regions by appropriate data. In the video text detection stage, text locations in each frame are found via an unsupervised clustering performed on the connected components produced by the stroke width transform (SWT). Since SWT needs an accurate edge map, we develop a novel edge detector which benefits from the geometric features revealed by the bandlet transform. Next, the motion patterns of the text objects of each frame are analyzed to localize video texts. The detected video text regions are removed, then the video is restored by an inpainting scheme. The proposed video inpainting approach applies spatio-temporal geometric flows extracted by bandlets to reconstruct the missing data. A 3D volume regularization algorithm, which takes advantage of bandlet bases in exploiting the anisotropic regularities, is introduced to carry out the inpainting task. The method does not need extra processes to satisfy visual consistency. The experimental results demonstrate the effectiveness of both our proposed video text detection approach and the video completion technique, and consequently the entire automatic video text removal and restoration process.

  11. Homogenous indium distribution in InGaN/GaN laser active structure grown by LP-MOCVD on bulk GaN crystal revealed by transmission electron microscopy and x-ray diffraction.

    Science.gov (United States)

    Kret, S; Dłużewski, P; Szczepańska, A; Zak, M; Czernecki, R; Kryśko, M; Leszczyński, M; Maciejewski, G

    2007-11-21

    We present transmission electron microscopy (TEM) and x-ray quantitative studies of the indium distribution in In(x)Ga(1-x)N/GaN multiple quantum wells (MQWs) with x = 0.1 and 0.18. The quantum wells were grown by low-pressure metalorganic chemical vapour deposition (LP-MOCVD) on a bulk, dislocation-free, mono-crystalline GaN substrate. By using the quantitative TEM methodology the absolute indium concentration was determined from the 0002 lattice fringe images by the strain measurement coupled with finite element (FE) simulations of surface relaxation of the TEM sample. In the x-ray diffraction (XRD) investigation, a new simulation program was applied to monitor the indium content and lateral composition gradients. We found a very high quality of the multiple quantum wells with lateral indium fluctuations no higher than Δx(L) = 0.025. The individual wells have very similar indium concentration and widths over the whole multiple quantum well (MQW) stack. We also show that the formation of 'false clusters' is not a limiting factor in indium distribution measurements. We interpreted the 'false clusters' as small In-rich islands formed on a sample surface during electron-beam exposure.

  12. Handbook of Microscopy for Nanotechnology

    Science.gov (United States)

    Yao, Nan; Wang, Zhong L.

    This handbook highlights various key microcopic techniques and their applications in this fast-growing field. Topics to be covered include the following: scanning near field optical microscopy, confocal optical microscopy, atomic force microscopy, magnetic force microscopy, scanning turning microscopy, high-resolution scanning electron microscopy, and many more.

  13. Videos, Podcasts and Livechats

    Medline Plus

    Full Text Available ... Care Disease Types FAQ Handout for Patients and Families Is It Right for You How to Get ... For the Media For Clinicians For Policymakers For Family Caregivers Glossary Menu In this section Links Videos ...

  14. Videos, Podcasts and Livechats

    Medline Plus

    Full Text Available ... Donate Search Search What Is It Definition Pediatric Palliative Care Disease Types FAQ Handout for Patients and Families ... Policymakers For Family Caregivers Glossary Resources Browse our palliative care resources below: Links Videos Podcasts Webinars For the ...

  15. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... Click to learn more... LOGIN CALENDAR DONATE NEWS Home Learn Back Learn about acoustic neuroma AN Facts ... Vision & Values Leadership & Staff Annual Reports Shop ANA Home Learn Educational Video Ronson and Kerri Albany Support ...

  16. Videos, Podcasts and Livechats

    Medline Plus

    Full Text Available ... Donate Search Search What Is It Definition Pediatric Palliative Care Disease Types FAQ Handout for Patients and ... Policymakers For Family Caregivers Glossary Resources Browse our palliative care resources below: Links Videos Podcasts Webinars For ...

  17. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... Click to learn more... LOGIN CALENDAR DONATE NEWS Home Learn Back Learn about acoustic neuroma AN Facts ... Vision & Values Leadership & Staff Annual Reports Shop ANA Home Learn Educational Video Howard of NJ Gloria hiking ...

  18. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... Mission, Vision & Values Shop ANA Leadership & Staff Annual Reports Acoustic Neuroma Association 600 Peachtree Parkway Suite 108 ... About ANA Mission, Vision & Values Leadership & Staff Annual Reports Shop ANA Home Learn Educational Video English English ...

  19. Videos, Podcasts and Livechats

    Medline Plus

    Full Text Available ... Disease Types Stories FAQ Handout for Patients and Families Is It Right for You How to Get ... For the Media For Clinicians For Policymakers For Family Caregivers Glossary Menu In this section Links Videos ...

  20. Videos, Podcasts and Livechats

    Medline Plus

    Full Text Available ... Search Search What Is It Definition Pediatric Palliative Care Disease Types FAQ Handout for Patients and Families ... For Family Caregivers Glossary Resources Browse our palliative care resources below: Links Videos Podcasts Webinars For the ...

  1. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... Educational Video Scott at the Grand Canyon Proton Center load more hold SHIFT key to load all load all Stay Connected with ANA Newly Diagnosed Living with AN Healthcare Providers Acoustic Neuroma Association Donate Now Newly Diagnosed ...

  2. The video violence debate.

    Science.gov (United States)

    Lande, R G

    1993-04-01

    Some researchers and theorists are convinced that graphic scenes of violence on television and in movies are inextricably linked to human aggression. Others insist that a link has not been conclusively established. This paper summarizes scientific studies that have informed these two perspectives. Although many instances of children and adults imitating video violence have been documented, no court has imposed liability for harm allegedly resulting from a video program, an indication that considerable doubt still exists about the role of video violence in stimulating human aggression. The author suggests that a small group of vulnerable viewers are probably more impressionable and therefore more likely to suffer deleterious effects from violent programming. He proposes that research on video violence be narrowed to identifying and describing the vulnerable viewer.

  3. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... a patient kit Keywords Join/Renew Programs Back Support Groups Is a support group for me? Find ... Events Video Library Photo Gallery One-on-One Support ANetwork Peer Support Program Community Connections Overview Find ...

  4. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... Click to learn more... LOGIN CALENDAR DONATE NEWS Home Learn Back Learn about acoustic neuroma AN Facts ... Vision & Values Leadership & Staff Annual Reports Shop ANA Home Learn Educational Video English English Arabic Catalan Chinese ( ...

  5. Video i VIA

    DEFF Research Database (Denmark)

    2012-01-01

    Artiklen beskriver et udviklingsprojekt, hvor 13 grupper af lærere på tværs af fag og uddannelser producerede video til undervsioningsbrug. Der beskrives forskellige tilgange og anvendelser samt læringen i projektet...

  6. Videos, Podcasts and Livechats

    Medline Plus

    Full Text Available ... to your Doctor Find a Provider Meet the Team Blog Articles & Stories News Resources Links Videos Podcasts ... to your Doctor Find a Provider Meet the Team Blog Articles & Stories News Provider Directory Donate Resources ...

  7. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... Click to learn more... LOGIN CALENDAR DONATE NEWS Home Learn Back Learn about acoustic neuroma AN Facts ... Vision & Values Leadership & Staff Annual Reports Shop ANA Home Learn Educational Video Keck Medicine of USC ANWarriors ...

  8. Videos, Podcasts and Livechats

    Medline Plus

    Full Text Available ... illness: Toby’s palliative care story Access the Provider Directory Handout for Patients and Families Is it Right ... Provider Meet the Team Blog Articles News Provider Directory Donate Resources Links Videos Podcasts Webinars For the ...

  9. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... Click to learn more... LOGIN EVENTS DONATE NEWS Home Learn Back Learn about acoustic neuroma AN Facts ... Vision & Values Leadership & Staff Annual Reports Shop ANA Home Learn Educational Video Scott at the Grand Canyon ...

  10. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... Is a support group for me? Find a Group Upcoming Events Video Library Photo Gallery One-on-One Support ANetwork Peer Support Program Community Connections Overview Find a Meeting ...

  11. Photos and Videos

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Observers are required to take photos and/or videos of all incidentally caught sea turtles, marine mammals, seabirds and unusual or rare fish. On the first 3...

  12. Videos, Podcasts and Livechats

    Medline Plus

    Full Text Available ... All rights reserved. GetPalliativeCare.org does not provide medical advice, diagnosis or treatment. ... the Team Blog Articles & Stories News Provider Directory Donate Resources Links Videos ...

  13. SEFIS Video Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is a fishery-independent survey that collects data on reef fish in southeast US waters using multiple gears, including chevron traps, video cameras, ROVs,...

  14. LEDs for fluorescence microscopy

    NARCIS (Netherlands)

    Young, I.T.; Garini, Y.; Dietrich, H.R.C.; Van Oel, W.; Liqui Lung, G.

    2004-01-01

    Traditional light sources for fluorescence microscopy have been mercury lamps, xenon lamps, and lasers. These sources have been essential in the development of fluorescence microscopy but each can have serious disadvantages: lack of near monochromaticity, heat generation, cost, lifetime of the light

  15. Lasers for nonlinear microscopy.

    Science.gov (United States)

    Wise, Frank

    2013-03-01

    Various versions of nonlinear microscopy are revolutionizing the life sciences, almost all of which are made possible because of the development of ultrafast lasers. In this article, the main properties and technical features of short-pulse lasers used in nonlinear microscopy are summarized. Recent research results on fiber lasers that will impact future instruments are also discussed.

  16. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... search for current job openings visit HHS USAJobs Home > NEI YouTube Videos > NEI YouTube Videos: Amblyopia NEI YouTube Videos YouTube Videos Home Age-Related Macular Degeneration Amblyopia Animations Blindness Cataract ...

  17. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... Amaurosis Low Vision Refractive Errors Retinopathy of Prematurity Science Spanish Videos Webinars NEI YouTube Videos: Amblyopia Embedded video for NEI YouTube Videos: Amblyopia NEI Home Contact Us A-Z Site Map NEI on Social Media Information in Spanish (Información en español) Website, ...

  18. Studenterproduceret video til eksamen

    DEFF Research Database (Denmark)

    Jensen, Kristian Nøhr; Hansen, Kenneth

    2016-01-01

    Formålet med denne artikel er at vise, hvordan læringsdesign og stilladsering kan anvendes til at skabe en ramme for studenterproduceret video til eksamen på videregående uddannelser. Artiklen tager udgangspunkt i en problemstilling, hvor uddannelsesinstitutionerne skal håndtere og koordinere...... de fagfaglige og mediefaglige undervisere et redskab til at fokusere og koordinere indsatsen frem mod målet med, at de studerende producerer og anvender video til eksamen....

  19. Video Editing System

    Science.gov (United States)

    Schlecht, Leslie E.; Kutler, Paul (Technical Monitor)

    1998-01-01

    This is a proposal for a general use system based, on the SGI IRIS workstation platform, for recording computer animation to videotape. In addition, this system would provide features for simple editing and enhancement. Described here are a list of requirements for the system, and a proposed configuration including the SGI VideoLab Integrator, VideoMedia VLAN animation controller and the Pioneer rewritable laserdisc recorder.

  20. Video Games and Citizenship

    OpenAIRE

    Bourgonjon, Jeroen; Soetaert, Ronald

    2013-01-01

    In their article "Video Games and Citizenship" Jeroen Bourgonjon and Ronald Soetaert argue that digitization problematizes and broadens our perspective on culture and popular media, and that this has important ramifications for our understanding of citizenship. Bourgonjon and Soetaert respond to the call of Gert Biesta for the contextualized study of young people's practices by exploring a particular aspect of digitization that affects young people, namely video games. They explore the new so...

  1. Android Video Streaming

    Science.gov (United States)

    2014-05-01

    be processed by a nearby high -performance computing asset and returned to a squad of Soldiers with annotations indicating the location of friendly and...is to change the resolution, bitrate, and/or framerate of the video being transmitted to the client, reducing the bandwidth requirements of the...video. This solution is typically not viable because a progressive download is required to have a constant resolution, bitrate, and framerate because

  2. Video-assisted thoracoscopic pneumonectomy.

    Science.gov (United States)

    Chen, Huan-Wen; Du, Ming

    2015-04-01

    Lung cancer often requires pneumonectomy. This procedure is challenging and usually performed by thoracotomy, which is traumatic and may involve complications. Video-assisted thoracoscopic surgery (VATS) lobectomy is a recognized procedure that has been accepted by surgeons. There is no standard procedure to perform a pneumonectomy using VATS. The aim of this paper is to share our experiences and to show our technique for performing a pneumonectomy using VATS. A 65-year-old man was admitted to the First Affiliated Hospital of Chongqing Medical University. A thoracic computed tomography (CT) scan revealed a 56 mm × 45 mm × 40 mm lesion in the left upper lung lobe. Lesions involving the left lower lung lobe were also identified and the subcarinal and hilar lymph nodes were enlarged. A VATS pneumonectomy was performed. The total surgery time was approximately 90 min, the intraoperative blood loss was 100 mL, the number of resected lymph nodes was 15; and the postoperative hospital stay was 8 days. Follow-up revealed no recurrence or metastasis for 6 months. Video-assisted thoracoscopic pneumonectomy is a safe and effective treatment procedure.

  3. Don't be fooled! Attentional responses to social cues in a face-to-face and video magic trick reveals greater top-down control for overt than covert attention.

    Science.gov (United States)

    Kuhn, Gustav; Teszka, Robert; Tenaw, Natalia; Kingstone, Alan

    2016-01-01

    People's attention is oriented towards faces, but the extent to which these social attention effects are under top down control is more ambiguous. Our first aim was to measure and compare, in real life and in the lab, people's top-down control over overt and covert shifts in reflexive social attention to the face of another. We employed a magic trick in which the magician used social cues (i.e. asking a question whilst establishing eye contact) to misdirect attention towards his face, and thus preventing participants from noticing a visible colour change to a playing card. Our results show that overall people spend more time looking at the magician's face when he is seen on video than in reality. Additionally, although most participants looked at the magician's face when misdirected, this tendency to look at the face was modulated by instruction (i.e., "keep your attention on the cards"), and therefore, by top down control. Moreover, while the card's colour change was fully visible, the majority of participants failed to notice the change, and critically, change detection (our measure of covert attention) was not affected by where people looked (overt attention). We conclude that there is a tendency to shift overt and covert attention reflexively to faces, but that people exert more top down control over this overt shift in attention. These finding are discussed within a new framework that focuses on the role of eye movements as an attentional process as well as a form of non-verbal communication. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Robust Adaptable Video Copy Detection

    DEFF Research Database (Denmark)

    Assent, Ira; Kremer, Hardy

    2009-01-01

    Video copy detection should be capable of identifying video copies subject to alterations e.g. in video contrast or frame rates. We propose a video copy detection scheme that allows for adaptable detection of videos that are altered temporally (e.g. frame rate change) and/or visually (e.g. change...... in contrast). Our query processing combines filtering and indexing structures for efficient multistep computation of video copies under this model. We show that our model successfully identifies altered video copies and does so more reliably than existing models....

  5. Crystal structure of an antifungal osmotin-like protein from Calotropis procera and its effects on Fusarium solani spores, as revealed by atomic force microscopy: Insights into the mechanism of action.

    Science.gov (United States)

    Ramos, Marcio V; de Oliveira, Raquel S B; Pereira, Humberto M; Moreno, Frederico B M B; Lobo, Marina D P; Rebelo, Luciana M; Brandão-Neto, José; de Sousa, Jeanlex S; Monteiro-Moreira, Ana C O; Freitas, Cléverson D T; Grangeiro, Thalles Barbosa

    2015-11-01

    CpOsm is an antifungal osmotin/thaumatin-like protein purified from the latex of Calotropis procera. The protein is relatively thermostable and retains its antifungal activity over a wide pH range; therefore, it may be useful in the development of new antifungal drugs or transgenic crops with enhanced resistance to phytopathogenic fungi. To gain further insight into the mechanism of action of CpOsm, its three-dimensional structure was determined, and the effects of the protein on Fusarium solani spores were investigated by atomic force microscopy (AFM). The atomic structure of CpOsm was solved at a resolution of 1.61Å, and it contained 205 amino acid residues and 192 water molecules, with a final R-factor of 18.12% and an Rfree of 21.59%. The CpOsm structure belongs to the thaumatin superfamily fold and is characterized by three domains stabilized by eight disulfide bonds and a prominent charged cleft, which runs the length of the front side of the molecule. Similarly to other antifungal thaumatin-like proteins, the cleft of CpOsm is predominantly acidic. AFM images of F. solani spores treated with CpOsm resulted in striking morphological changes being induced by the protein. Spores treated with CpOsm were wrinkled, and the volume of these cells was reduced by approximately 80%. Treated cells were covered by a shell of CpOsm molecules, and the leakage of cytoplasmic content from these cells was also observed. Based on the structural features of CpOsm and the effects that the protein produces on F. solani spores, a possible mechanism of action is suggested and discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. A direct interaction between the sigma-1 receptor and the hERG voltage-gated K+ channel revealed by atomic force microscopy and homogeneous time-resolved fluorescence (HTRF®).

    Science.gov (United States)

    Balasuriya, Dilshan; D'Sa, Lauren; Talker, Ronel; Dupuis, Elodie; Maurin, Fabrice; Martin, Patrick; Borgese, Franck; Soriani, Olivier; Edwardson, J Michael

    2014-11-14

    The sigma-1 receptor is an endoplasmic reticulum chaperone protein, widely expressed in central and peripheral tissues, which can translocate to the plasma membrane and modulate the function of various ion channels. The human ether-à-go-go-related gene encodes hERG, a cardiac voltage-gated K(+) channel that is abnormally expressed in many human cancers and is known to interact functionally with the sigma-1 receptor. Our aim was to investigate the nature of the interaction between the sigma-1 receptor and hERG. We show that the two proteins can be co-isolated from a detergent extract of stably transfected HEK-293 cells, consistent with a direct interaction between them. Atomic force microscopy imaging of the isolated protein confirmed the direct binding of the sigma-1 receptor to hERG monomers, dimers, and tetramers. hERG dimers and tetramers became both singly and doubly decorated by sigma-1 receptors; however, hERG monomers were only singly decorated. The distribution of angles between pairs of sigma-1 receptors bound to hERG tetramers had two peaks, at ∼90 and ∼180° in a ratio of ∼2:1, indicating that the sigma-1 receptor interacts with hERG with 4-fold symmetry. Homogeneous time-resolved fluorescence (HTRF®) allowed the detection of the interaction between the sigma-1 receptor and hERG within the plane of the plasma membrane. This interaction was resistant to sigma ligands, but was decreased in response to cholesterol depletion of the membrane. We suggest that the sigma-1 receptor may bind to hERG in the endoplasmic reticulum, aiding its assembly and trafficking to the plasma membrane. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  7. Wide-range high-resolution transmission electron microscopy reveals morphological and distributional changes of endomembrane compartments during log to stationary transition of growth phase in tobacco BY-2 cells.

    Science.gov (United States)

    Toyooka, Kiminori; Sato, Mayuko; Kutsuna, Natsumaro; Higaki, Takumi; Sawaki, Fumie; Wakazaki, Mayumi; Goto, Yumi; Hasezawa, Seiichiro; Nagata, Noriko; Matsuoka, Ken

    2014-09-01

    Rapid growth of plant cells by cell division and expansion requires an endomembrane trafficking system. The endomembrane compartments, such as the Golgi stacks, endosome and vesicles, are important in the synthesis and trafficking of cell wall materials during cell elongation. However, changes in the morphology, distribution and number of these compartments during the different stages of cell proliferation and differentiation have not yet been clarified. In this study, we examined these changes at the ultrastructural level in tobacco Bright yellow 2 (BY-2) cells during the log and stationary phases of growth. We analyzed images of the BY-2 cells prepared by the high-pressure freezing/freeze substitution technique with the aid of an auto-acquisition transmission electron microscope system. We quantified the distribution of secretory and endosomal compartments in longitudinal sections of whole cells by using wide-range gigapixel-class images obtained by merging thousands of transmission electron micrographs. During the log phase, all Golgi stacks were composed of several thick cisternae. Approximately 20 vesicle clusters (VCs), including the trans-Golgi network and secretory vesicle cluster, were observed throughout the cell. In the stationary-phase cells, Golgi stacks were thin with small cisternae, and only a few VCs were observed. Nearly the same number of multivesicular body and small high-density vesicles were observed in both the stationary and log phases. Results from electron microscopy and live fluorescence imaging indicate that the morphology and distribution of secretory-related compartments dramatically change when cells transition from log to stationary phases of growth. © The Author 2014. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  8. Robust video object cosegmentation.

    Science.gov (United States)

    Wang, Wenguan; Shen, Jianbing; Li, Xuelong; Porikli, Fatih

    2015-10-01

    With ever-increasing volumes of video data, automatic extraction of salient object regions became even more significant for visual analytic solutions. This surge has also opened up opportunities for taking advantage of collective cues encapsulated in multiple videos in a cooperative manner. However, it also brings up major challenges, such as handling of drastic appearance, motion pattern, and pose variations, of foreground objects as well as indiscriminate backgrounds. Here, we present a cosegmentation framework to discover and segment out common object regions across multiple frames and multiple videos in a joint fashion. We incorporate three types of cues, i.e., intraframe saliency, interframe consistency, and across-video similarity into an energy optimization framework that does not make restrictive assumptions on foreground appearance and motion model, and does not require objects to be visible in all frames. We also introduce a spatio-temporal scale-invariant feature transform (SIFT) flow descriptor to integrate across-video correspondence from the conventional SIFT-flow into interframe motion flow from optical flow. This novel spatio-temporal SIFT flow generates reliable estimations of common foregrounds over the entire video data set. Experimental results show that our method outperforms the state-of-the-art on a new extensive data set (ViCoSeg).

  9. Video games do affect social outcomes: a meta-analytic review of the effects of violent and prosocial video game play.

    Science.gov (United States)

    Greitemeyer, Tobias; Mügge, Dirk O

    2014-05-01

    Whether video game play affects social behavior is a topic of debate. Many argue that aggression and helping are affected by video game play, whereas this stance is disputed by others. The present research provides a meta-analytical test of the idea that depending on their content, video games do affect social outcomes. Data from 98 independent studies with 36,965 participants revealed that for both violent video games and prosocial video games, there was a significant association with social outcomes. Whereas violent video games increase aggression and aggression-related variables and decrease prosocial outcomes, prosocial video games have the opposite effects. These effects were reliable across experimental, correlational, and longitudinal studies, indicating that video game exposure causally affects social outcomes and that there are both short- and long-term effects.

  10. Further observations on cerebellar climbing fibers. A study by means of light microscopy, confocal laser scanning microscopy and scanning and transmission electron microscopy.

    Science.gov (United States)

    Castejón, O J; Castejón, H V; Alvarado, M V

    2000-12-01

    The intracortical pathways of climbing fibers were traced in several vertebrate cerebella using light microscopy, confocal laser scanning microscopy, scanning and transmission electron microscopy. They were identified as fine fibers up to 1(micron thick, with a characteristic crossing-over bifurcation pattern. Climbing fiber collaterals were tridimensionally visualized forming thin climbing fiber glomeruli in the granular layer. Confocal laser scanning microscopy revealed three types of collateral processes at the interface between granular and Purkinje cell layers. Scanning electron microscopy showed climbing fiber retrograde collaterals in the molecular layer. Asymmetric synaptic contacts of climbing fibers with Purkinje dendritic spines and stellate neuron dendrites were characterized by transmission electron microscopy. Correlative microscopy allowed us to obtain the basic three-dimensional morphological features of climbing fibers in several vertebrates and to show with more accuracy a higher degree of lateral collateralization of these fibers within the cerebellar cortex. The correlative microscopy approach provides new views in the cerebellar cortex information processing.

  11. How musical are music video game players?

    Science.gov (United States)

    Pasinski, Amanda C; Hannon, Erin E; Snyder, Joel S

    2016-10-01

    Numerous studies have shown that formal musical training is associated with sensory, motor, and cognitive advantages in individuals of various ages. However, the nature of the observed differences between musicians and nonmusicians is poorly understood, and little is known about the listening skills of individuals who engage in alternative types of everyday musical activities. Here, we show that people who have frequently played music video games outperform nonmusicians controls on a battery of music perception tests. These findings reveal that enhanced musical aptitude can be found among individuals who play music video games, raising the possibility that music video games could potentially enhance music perception skills in individuals across a broad spectrum of society who are otherwise unable to invest the time and/or money required to learn a musical instrument.

  12. Confocal Raman microscopy

    CERN Document Server

    Dieing, Thomas; Hollricher, Olaf

    2018-01-01

    This second edition provides a cutting-edge overview of physical, technical and scientific aspects related to the widely used analytical method of confocal Raman microscopy. The book includes expanded background information and adds insights into how confocal Raman microscopy, especially 3D Raman imaging, can be integrated with other methods to produce a variety of correlative microscopy combinations. The benefits are then demonstrated and supported by numerous examples from the fields of materials science, 2D materials, the life sciences, pharmaceutical research and development, as well as the geosciences.

  13. Deep video deblurring

    KAUST Repository

    Su, Shuochen

    2016-11-25

    Motion blur from camera shake is a major problem in videos captured by hand-held devices. Unlike single-image deblurring, video-based approaches can take advantage of the abundant information that exists across neighboring frames. As a result the best performing methods rely on aligning nearby frames. However, aligning images is a computationally expensive and fragile procedure, and methods that aggregate information must therefore be able to identify which regions have been accurately aligned and which have not, a task which requires high level scene understanding. In this work, we introduce a deep learning solution to video deblurring, where a CNN is trained end-to-end to learn how to accumulate information across frames. To train this network, we collected a dataset of real videos recorded with a high framerate camera, which we use to generate synthetic motion blur for supervision. We show that the features learned from this dataset extend to deblurring motion blur that arises due to camera shake in a wide range of videos, and compare the quality of results to a number of other baselines.

  14. International Multidisciplinary Microscopy Congress

    CERN Document Server

    Oral, Ahmet; Ozer, Mehmet; InterM; INTERM2013

    2014-01-01

    The International Multidisciplinary Microscopy Congress (INTERM2013) was organized on October 10-13, 2013. The aim of the congress was to bring together scientists from various branches to discuss the latest advances in the field of microscopy. The contents of the congress have been broadened to a more "interdisciplinary" scope, so as to allow all scientists working on related subjects to participate and present their work. These proceedings include 39 peer-reviewed technical papers, submitted by leading academic and research institutions from over 12 countries and representing some of the most cutting-edge research available. The 39 papers are grouped into the following sections: - Applications of Microscopy in the Physical Sciences - Applications of Microscopy in the Biological Sciences

  15. Clinical specular microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hirst, L.W.; Laing, R.A.

    1987-01-01

    This book provides the general ophthalmologist with a guide to the clinical applications of specular microscopy. Important material is included on laser injury, cataract surgery, corneal transplants, glaucoma, uveitis, and trauma.

  16. Talking Video in 'Everyday Life'

    DEFF Research Database (Denmark)

    McIlvenny, Paul

    For better or worse, video technologies have made their way into many domains of social life, for example in the domain of therapeutics. Techniques such as Marte Meo, Video Interaction Guidance (ViG), Video-Enhanced Reflection on Communication, Video Home Training and Video intervention....../prevention (VIP) all promote the use of video as a therapeutic tool. This paper focuses on media therapeutics and the various in situ uses of video technologies in the mass media for therapeutic purposes. Reality TV parenting programmes such as Supernanny, Little Angels, The House of Tiny Tearaways, Honey, We......’re Killing the Kids, and Driving Mum and Dad Mad all use video as a prominent element of not only the audiovisual spectacle of reality television but also the interactional therapy, counselling, coaching and/or instruction intrinsic to these programmes. Thus, talk-on-video is used to intervene...

  17. Quantitative dispersion microscopy

    OpenAIRE

    Fu, Dan; Choi, Wonshik; Sung, Yongjin; Yaqoob, Zahid; Ramachandra R Dasari; Feld, Michael

    2010-01-01

    Refractive index dispersion is an intrinsic optical property and a useful source of contrast in biological imaging studies. In this report, we present the first dispersion phase imaging of living eukaryotic cells. We have developed quantitative dispersion microscopy based on the principle of quantitative phase microscopy. The dual-wavelength quantitative phase microscope makes phase measurements at 310 nm and 400 nm wavelengths to quantify dispersion (refractive index increment ratio) of live...

  18. Video y desarrollo rural

    Directory of Open Access Journals (Sweden)

    Fraser Colin

    2015-01-01

    Full Text Available Las primeras experiencias de video rural fueron realizadas en Perú y México. El proyecto peruano es conocido como CESPAC (Centro de Servicios de Pedagogía Audiovisual para la Capacitación. Con financiamiento externo de la FAO fue iniciado en la década del 70. El proyecto mexicano fue bautizado con el nombre de PRODERITH (Programa de Desarrollo Rural Integrado del Trópico Húmedo. Su componente de video rural tuvo un éxito muy particular a nivel de base.La evaluación concluyó en que el video rural como sistema de comunicación social para el desarrollo es excelente y de bajo costo

  19. A Big Video Manifesto

    DEFF Research Database (Denmark)

    Mcilvenny, Paul Bruce; Davidsen, Jacob

    2017-01-01

    For the last few years, we have witnessed a hype about the potential results and insights that quantitative big data can bring to the social sciences. The wonder of big data has moved into education, traffic planning, and disease control with a promise of making things better with big numbers...... and beautiful visualisations. However, we also need to ask what the tools of big data can do both for the Humanities and for more interpretative approaches and methods. Thus, we prefer to explore how the power of computation, new sensor technologies and massive storage can also help with video-based qualitative...... inquiry, such as video ethnography, ethnovideo, performance documentation, anthropology and multimodal interaction analysis. That is why we put forward, half-jokingly at first, a Big Video manifesto to spur innovation in the Digital Humanities....

  20. Online video examination

    DEFF Research Database (Denmark)

    Qvist, Palle

    courses are accredited to the master programme. The programme is online, worldwide and on demand. It recruits students from all over the world. The programme is organized exemplary in accordance the principles in the problem-based and project-based learning method used at Aalborg University where students......The Master programme in Problem-Based Learning in Engineering and Science, MPBL (www.mpbl.aau.dk), at Aalborg University, is an international programme offering formalized staff development. The programme is also offered in smaller parts as single subject courses (SSC). Passed single subject...... have large influence on their own teaching, learning and curriculum. The programme offers streamed videos in combination with other learning resources. It is a concept which offers video as pure presentation - video lectures - but also as an instructional tool which gives the students the possibility...

  1. Brains on video games.

    Science.gov (United States)

    Bavelier, Daphne; Green, C Shawn; Han, Doug Hyun; Renshaw, Perry F; Merzenich, Michael M; Gentile, Douglas A

    2011-11-18

    The popular press is replete with stories about the effects of video and computer games on the brain. Sensationalist headlines claiming that video games 'damage the brain' or 'boost brain power' do not do justice to the complexities and limitations of the studies involved, and create a confusing overall picture about the effects of gaming on the brain. Here, six experts in the field shed light on our current understanding of the positive and negative ways in which playing video games can affect cognition and behaviour, and explain how this knowledge can be harnessed for educational and rehabilitation purposes. As research in this area is still in its early days, the contributors of this Viewpoint also discuss several issues and challenges that should be addressed to move the field forward.

  2. Video library for video imaging detection at intersection stop lines.

    Science.gov (United States)

    2010-04-01

    The objective of this activity was to record video that could be used for controlled : evaluation of video image vehicle detection system (VIVDS) products and software upgrades to : existing products based on a list of conditions that might be diffic...

  3. User aware video streaming

    Science.gov (United States)

    Kerofsky, Louis; Jagannath, Abhijith; Reznik, Yuriy

    2015-03-01

    We describe the design of a video streaming system using adaptation to viewing conditions to reduce the bitrate needed for delivery of video content. A visual model is used to determine sufficient resolution needed under various viewing conditions. Sensors on a mobile device estimate properties of the viewing conditions, particularly the distance to the viewer. We leverage the framework of existing adaptive bitrate streaming systems such as HLS, Smooth Streaming or MPEG-DASH. The client rate selection logic is modified to include a sufficient resolution computed using the visual model and the estimated viewing conditions. Our experiments demonstrate significant bitrate savings compare to conventional streaming methods which do not exploit viewing conditions.

  4. Contextual analysis of videos

    CERN Document Server

    Thida, Myo; Monekosso, Dorothy

    2013-01-01

    Video context analysis is an active and vibrant research area, which provides means for extracting, analyzing and understanding behavior of a single target and multiple targets. Over the last few decades, computer vision researchers have been working to improve the accuracy and robustness of algorithms to analyse the context of a video automatically. In general, the research work in this area can be categorized into three major topics: 1) counting number of people in the scene 2) tracking individuals in a crowd and 3) understanding behavior of a single target or multiple targets in the scene.

  5. Video-based rendering

    CERN Document Server

    Magnor, Marcus A

    2005-01-01

    Driven by consumer-market applications that enjoy steadily increasing economic importance, graphics hardware and rendering algorithms are a central focus of computer graphics research. Video-based rendering is an approach that aims to overcome the current bottleneck in the time-consuming modeling process and has applications in areas such as computer games, special effects, and interactive TV. This book offers an in-depth introduction to video-based rendering, a rapidly developing new interdisciplinary topic employing techniques from computer graphics, computer vision, and telecommunication en

  6. CERN Video News

    CERN Multimedia

    2003-01-01

    From Monday you can see on the web the new edition of CERN's Video News. Thanks to a collaboration between the audiovisual teams at CERN and Fermilab, you can see a report made by the American laboratory. The clip concerns the LHC magnets that are being constructed at Fermilab. Also in the programme: the spectacular rotation of one of the ATLAS coils, the arrival at CERN of the first American magnet made at Brookhaven, the story of the discovery 20 years ago of the W and Z bosons at CERN. http://www.cern.ch/video or Bulletin web page.

  7. Video special effects editing in MPEG-2 compressed video

    OpenAIRE

    Fernando, WAC; Canagarajah, CN; Bull, David

    2000-01-01

    With the increase of digital technology in video production, several types of complex video special effects editing have begun to appear in video clips. In this paper we consider fade-out and fade-in special effects editing in MPEG-2 compressed video without full frame decompression and motion estimation. We estimated the DCT coefficients and use these coefficients together with the existing motion vectors to produce these special effects editing in compressed domain. Results show that both o...

  8. Students' Experiences with Live Video-Streamed Teaching Classes

    DEFF Research Database (Denmark)

    Jelsbak, Vibe Alopaeus; Buus, Lillian; Thorsen, Jonas

    2017-01-01

    Students' Experiences with Live Video-Streamed Classes The bachelor programme in biomedical laboratory technology at VIA Faculty of Health Sciences offers a combination of live video-streamed and traditional teaching. It is the student’s individual choice whether to attend classes on......-site or to attend classes from home via live video-stream. Our previous studies revealed that interaction and dialog between attendants were reduced in the live-streamed sessions compared to on-site teaching, and that the main reasons were technological issues and the teacher’s choice of teaching methods. One......-site and live video-streamed teaching. The results document a continuous progress in technological transparency, as the live video-streamed classes increasingly support the student’s flexibility in ways of attending and interacting in classes. Interaction is facilitated through teacher driven support, resulting...

  9. A video annotation methodology for interactive video sequence generation

    NARCIS (Netherlands)

    C.A. Lindley; R.A. Earnshaw; J.A. Vince

    2001-01-01

    textabstractThe FRAMES project within the RDN CRC (Cooperative Research Centre for Research Data Networks) has developed an experimental environment for dynamic virtual video sequence synthesis from databases of video data. A major issue for the development of dynamic interactive video applications

  10. Streaming Video--The Wave of the Video Future!

    Science.gov (United States)

    Brown, Laura

    2004-01-01

    Videos and DVDs give the teachers more flexibility than slide projectors, filmstrips, and 16mm films but teachers and students are excited about a new technology called streaming. Streaming allows the educators to view videos on demand via the Internet, which works through the transfer of digital media like video, and voice data that is received…

  11. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... Grants and Funding Extramural Research Division of Extramural Science Programs Division of Extramural Activities Extramural Contacts NEI ... Amaurosis Low Vision Refractive Errors Retinopathy of Prematurity Science Spanish Videos Webinars NEI YouTube Videos: Amblyopia Embedded ...

  12. Rheumatoid Arthritis Educational Video Series

    Medline Plus

    Full Text Available ... Corner / Patient Webcasts / Rheumatoid Arthritis Educational Video Series Rheumatoid Arthritis Educational Video Series This series of five ... was designed to help you learn more about Rheumatoid Arthritis (RA). You will learn how the diagnosis ...

  13. Rheumatoid Arthritis Educational Video Series

    Medline Plus

    Full Text Available ... Our Staff Rheumatology Specialty Centers You are here: Home / Patient Corner / Patient Webcasts / Rheumatoid Arthritis Educational Video ... to take a more active role in your care. The information in these videos should not take ...

  14. Rheumatoid Arthritis Educational Video Series

    Medline Plus

    Full Text Available ... will allow you to take a more active role in your care. The information in these videos ... Stategies to Increase your Level of Physical Activity Role of Body Weight in Osteoarthritis Educational Videos for ...

  15. Rheumatoid Arthritis Educational Video Series

    Medline Plus

    Full Text Available ... here. Will You Support the Education of Arthritis Patients? Each year, over 1 million people visit this ... of Body Weight in Osteoarthritis Educational Videos for Patients Rheumatoid Arthritis Educational Video Series Psoriatic Arthritis 101 ...

  16. Videos & Tools: MedlinePlus

    Science.gov (United States)

    ... of this page: https://medlineplus.gov/videosandcooltools.html Videos & Tools To use the sharing features on this page, please enable JavaScript. Watch health videos on topics such as anatomy, body systems, and ...

  17. Health Videos: MedlinePlus

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/anatomyvideos.html.htm Health Videos To use the sharing features on this page, please enable JavaScript. These animated videos show the anatomy of body parts and organ ...

  18. Scanning laser video camera/ microscope

    Science.gov (United States)

    Wang, C. P.; Bow, R. T.

    1984-10-01

    A laser scanning system capable of scanning at standard video rate has been developed. The scanning mirrors, circuit design and system performance, as well as its applications to video cameras and ultra-violet microscopes, are discussed.

  19. Astronomy Video Contest

    Science.gov (United States)

    McFarland, John

    2008-05-01

    During Galileo's lifetime his staunchest supporter was Johannes Kepler, Imperial Mathematician to the Holy Roman Emperor. Johannes Kepler will be in St. Louis to personally offer a tribute to Galileo. Set Galileo's astronomy discoveries to music and you get the newest song by the well known acappella group, THE CHROMATICS. The song, entitled "Shoulders of Giants” was written specifically for IYA-2009 and will be debuted at this conference. The song will also be used as a base to create a music video by synchronizing a person's own images to the song's lyrics and tempo. Thousands of people already do this for fun and post their videos on YOU TUBE and other sites. The ASTRONOMY VIDEO CONTEST will be launched as a vehicle to excite, enthuse and educate people about astronomy and science. It will be an annual event administered by the Johannes Kepler Project and will continue to foster the goals of IYA-2009 for years to come. During this presentation the basic categories, rules, and prizes for the Astronomy Video Contest will be covered and finally the new song "Shoulders of Giants” by THE CHROMATICS will be unveiled

  20. Provocative Video Scenarios

    DEFF Research Database (Denmark)

    Caglio, Agnese

    This paper presents the use of ”provocative videos”, as a tool to support and deepen findings from ethnographic investigation on the theme of remote videocommunication. The videos acted as a resource to also investigate potential for novel technologies supporting continuous connection between...

  1. Fast Aerial Video Stitching

    Directory of Open Access Journals (Sweden)

    Jing Li

    2014-10-01

    Full Text Available The highly efficient and robust stitching of aerial video captured by unmanned aerial vehicles (UAVs is a challenging problem in the field of robot vision. Existing commercial image stitching systems have seen success with offline stitching tasks, but they cannot guarantee high-speed performance when dealing with online aerial video sequences. In this paper, we present a novel system which has an unique ability to stitch high-frame rate aerial video at a speed of 150 frames per second (FPS. In addition, rather than using a high-speed vision platform such as FPGA or CUDA, our system is running on a normal personal computer. To achieve this, after the careful comparison of the existing invariant features, we choose the FAST corner and binary descriptor for efficient feature extraction and representation, and present a spatial and temporal coherent filter to fuse the UAV motion information into the feature matching. The proposed filter can remove the majority of feature correspondence outliers and significantly increase the speed of robust feature matching by up to 20 times. To achieve a balance between robustness and efficiency, a dynamic key frame-based stitching framework is used to reduce the accumulation errors. Extensive experiments on challenging UAV datasets demonstrate that our approach can break through the speed limitation and generate an accurate stitching image for aerial video stitching tasks.

  2. Video Content Foraging

    NARCIS (Netherlands)

    van Houten, Ynze; Schuurman, Jan Gerrit; Verhagen, Pleunes Willem; Enser, Peter; Kompatsiaris, Yiannis; O’Connor, Noel E.; Smeaton, Alan F.; Smeulders, Arnold W.M.

    2004-01-01

    With information systems, the real design problem is not increased access to information, but greater efficiency in finding useful information. In our approach to video content browsing, we try to match the browsing environment with human information processing structures by applying ideas from

  3. Internet video search

    NARCIS (Netherlands)

    Snoek, C.G.M.; Smeulders, A.W.M.

    2011-01-01

    In this tutorial, we focus on the challenges in internet video search, present methods how to achieve state-of-the-art performance while maintaining efficient execution, and indicate how to obtain improvements in the near future. Moreover, we give an overview of the latest developments and future

  4. Videos, Podcasts and Livechats

    Medline Plus

    Full Text Available ... Donate Resources Links Videos Podcasts Webinars For the Media For Clinicians For Policymakers For Family Caregivers Glossary Sign Up for Our Blog Subscribe to Blog Enter your email address to subscribe to this blog and receive notifications of new posts by email. Email Address CLOSE Home About ...

  5. Scalable Video Coding

    NARCIS (Netherlands)

    Choupani, R.

    2017-01-01

    With the rapid improvements in digital communication technologies, distributing high-definition visual information has become more widespread. However, the available technologies were not sufficient to support the rising demand for high-definition video. This situation is further complicated when

  6. Video processing project

    CSIR Research Space (South Africa)

    Globisch, R

    2009-03-01

    Full Text Available Video processing source code for algorithms and tools used in software media pipelines (e.g. image scalers, colour converters, etc.) The currently available source code is written in C++ with their associated libraries and DirectShow- Filters....

  7. Video narrativer i sygeplejerskeuddannelsen

    DEFF Research Database (Denmark)

    Jensen, Inger

    2009-01-01

    I artiklen gives nogle bud på hvordan video narrativer kan bruges i sygeplejerskeuddannelsen som triggers, der åbner for diskussioner og udvikling af meningsfulde holdninger til medmennesker. Det belyses også hvordan undervisere i deres didaktiske overvejelser kan inddrage elementer fra teori om...

  8. Streaming-video produktion

    DEFF Research Database (Denmark)

    Grønkjær, Poul

    2004-01-01

     E-learning Lab på Aalborg Universitet har i forbindelse med forskningsprojektet Virtuelle Læringsformer og Læringsmiljøer foretaget en række praktiske eksperimenter med streaming-video produktioner. Hensigten med denne artikel er at formidle disse erfaringer. Artiklen beskriver hele produktionsf...... E-learning Lab på Aalborg Universitet har i forbindelse med forskningsprojektet Virtuelle Læringsformer og Læringsmiljøer foretaget en række praktiske eksperimenter med streaming-video produktioner. Hensigten med denne artikel er at formidle disse erfaringer. Artiklen beskriver hele...... produktionsforløbet: fra ide til færdigt produkt, forskellige typer af præsentationer, dramaturgiske overvejelser samt en konceptskitse. Streaming-video teknologien er nu så udviklet med et så tilfredsstillende audiovisuelt udtryk at vi kan begynde at fokusere på, hvilket indhold der er velegnet til at blive gjort...... tilgængeligt uafhængigt af tid og sted. Afslutningsvis er der en række kildehenvisninger, blandt andet en oversigt over de streaming-video produktioner, som denne artikel bygger på....

  9. Characteristics of Instructional Videos

    Science.gov (United States)

    Beheshti, Mobina; Taspolat, Ata; Kaya, Omer Sami; Sapanca, Hamza Fatih

    2018-01-01

    Nowadays, video plays a significant role in education in terms of its integration into traditional classes, the principal delivery system of information in classes particularly in online courses as well as serving as a foundation of many blended classes. Hence, education is adopting a modern approach of instruction with the target of moving away…

  10. Videos, Podcasts and Livechats

    Medline Plus

    Full Text Available Home About Donate Search Search What Is It Definition Pediatric Palliative Care Disease Types FAQ Handout for Patients and Families Is It Right for You How to Get It Talk to your Doctor Find a Provider Meet the Team Blog Articles & Stories News Resources Links Videos Podcasts ...

  11. Mobiele video voor bedrijfscommunicatie

    NARCIS (Netherlands)

    Niamut, O.A.; Weerdt, C.A. van der; Havekes, A.

    2009-01-01

    Het project Penta Mobilé liep van juni tot november 2009 en had als doel de mogelijkheden van mobiele video voor bedrijfscommunicatie toepassingen in kaart te brengen. Dit onderzoek werd uitgevoerd samen met vijf (‘Penta’) partijen: Business Tales, Condor Digital, European Communication Projects

  12. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... Surgery What is acoustic neuroma Diagnosing Symptoms Side effects ... Groups Is a support group for me? Find a Group Upcoming Events Video Library Photo Gallery One-on-One Support ANetwork Peer Support Program Community Connections Overview Find a Meeting ...

  13. Developing a Video Steganography Toolkit

    OpenAIRE

    Ridgway, James; Stannett, Mike

    2014-01-01

    Although techniques for separate image and audio steganography are widely known, relatively little has been described concerning the hiding of information within video streams ("video steganography"). In this paper we review the current state of the art in this field, and describe the key issues we have encountered in developing a practical video steganography system. A supporting video is also available online at http://www.youtube.com/watch?v=YhnlHmZolRM

  14. [Virtual microscopy in pathology teaching and postgraduate training (continuing education)].

    Science.gov (United States)

    Sinn, H P; Andrulis, M; Mogler, C; Schirmacher, P

    2008-11-01

    As with conventional microscopy, virtual microscopy permits histological tissue sections to be viewed on a computer screen with a free choice of viewing areas and a wide range of magnifications. This, combined with the possibility of linking virtual microscopy to E-Learning courses, make virtual microscopy an ideal tool for teaching and postgraduate training in pathology. Uses of virtual microscopy in pathology teaching include blended learning with the presentation of digital teaching slides in the internet parallel to presentation in the histology lab, extending student access to histology slides beyond the lab. Other uses are student self-learning in the Internet, as well as the presentation of virtual slides in the classroom with or without replacing real microscopes. Successful integration of virtual microscopy depends on its embedding in the virtual classroom and the creation of interactive E-learning content. Applications derived from this include the use of virtual microscopy in video clips, podcasts, SCORM modules and the presentation of virtual microscopy using interactive whiteboards in the classroom.

  15. Confocal Raman Microscopy

    CERN Document Server

    Dieing, Thomas; Toporski, Jan

    2011-01-01

    Confocal Raman Microscopy is a relatively new technique that allows chemical imaging without specific sample preparation. By integrating a sensitive Raman spectrometer within a state-of-the-art microscope, Raman microscopy with a spatial resolution down to 200nm laterally and 500nm vertically can be achieved using visible light excitation. Recent developments in detector and computer technology as well as optimized instrument design have reduced integration times of Raman spectra by orders of magnitude, so that complete images consisting of tens of thousands of Raman spectra can be acquired in seconds or minutes rather than hours, which used to be standard just one decade ago. The purpose of this book is to provide the reader a comprehensive overview of the rapidly developing field of Confocal Raman Microscopy and its applications.

  16. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... NEI YouTube Videos: Amblyopia NEI YouTube Videos YouTube Videos Home Age-Related Macular Degeneration Amblyopia Animations Blindness Cataract Convergence Insufficiency Diabetic Eye Disease Dilated Eye Exam Dry Eye For Kids Glaucoma ...

  17. SPECIAL REPORT: Creating Conference Video

    Directory of Open Access Journals (Sweden)

    Noel F. Peden

    2008-12-01

    Full Text Available Capturing video at a conference is easy. Doing it so the product is useful is another matter. Many subtle problems come into play so that video and audio obtained can be used to create a final product. This article discusses what the author learned in the two years of shooting and editing video for Code4Lib conference.

  18. CERN Video News on line

    CERN Multimedia

    2003-01-01

    The latest CERN video news is on line. In this issue : an interview with the Director General and reports on the new home for the DELPHI barrel and the CERN firemen's spectacular training programme. There's also a vintage video news clip from 1954. See: www.cern.ch/video or Bulletin web page

  19. We All Stream for Video

    Science.gov (United States)

    Technology & Learning, 2008

    2008-01-01

    More than ever, teachers are using digital video to enhance their lessons. In fact, the number of schools using video streaming increased from 30 percent to 45 percent between 2004 and 2006, according to Market Data Retrieval. Why the popularity? For starters, video-streaming products are easy to use. They allow teachers to punctuate lessons with…

  20. Social Properties of Mobile Video

    Science.gov (United States)

    Mitchell, April Slayden; O'Hara, Kenton; Vorbau, Alex

    Mobile video is now an everyday possibility with a wide array of commercially available devices, services, and content. These new technologies have created dramatic shifts in the way video-based media can be produced, consumed, and delivered by people beyond the familiar behaviors associated with fixed TV and video technologies. Such technology revolutions change the way users behave and change their expectations in regards to their mobile video experiences. Building upon earlier studies of mobile video, this paper reports on a study using diary techniques and ethnographic interviews to better understand how people are using commercially available mobile video technologies in their everyday lives. Drawing on reported episodes of mobile video behavior, the study identifies the social motivations and values underpinning these behaviors that help characterize mobile video consumption beyond the simplistic notion of viewing video only to kill time. This paper also discusses the significance of user-generated content and the usage of video in social communities through the description of two mobile video technology services that allow users to create and share content. Implications for adoption and design of mobile video technologies and services are discussed as well.

  1. Video Analysis of Rolling Cylinders

    Science.gov (United States)

    Phommarach, S.; Wattanakasiwich, P.; Johnston, I.

    2012-01-01

    In this work, we studied the rolling motion of solid and hollow cylinders down an inclined plane at different angles. The motions were captured on video at 300 frames s[superscript -1], and the videos were analyzed frame by frame using video analysis software. Data from the real motion were compared with the theory of rolling down an inclined…

  2. Video Games and Digital Literacies

    Science.gov (United States)

    Steinkuehler, Constance

    2010-01-01

    Today's youth are situated in a complex information ecology that includes video games and print texts. At the basic level, video game play itself is a form of digital literacy practice. If we widen our focus from the "individual player + technology" to the online communities that play them, we find that video games also lie at the nexus of a…

  3. Rheumatoid Arthritis Educational Video Series

    Medline Plus

    Full Text Available ... Corner / Patient Webcasts / Rheumatoid Arthritis Educational Video Series Rheumatoid Arthritis Educational Video Series This series of five videos ... Your Arthritis Managing Chronic Pain and Depression in Arthritis Nutrition & Rheumatoid Arthritis Arthritis and Health-related Quality of Life ...

  4. Confocal scanning microscopy

    DEFF Research Database (Denmark)

    Bariani, Paolo

    This report is based on a metrological investigation on confocal microscopy technique carried out by Uffe Rolf Arlø Theilade and Paolo Bariani. The purpose of the experimental activity was twofold a metrological instrument characterization and application to assessment of rough PP injection moulded...... replicated topography. Confocal microscopy is seen to be a promising technique in metrology of microstructures. Some limitations with respect to surface metrology were found during the experiments. The experiments were carried out using a Zeiss LSM 5 Pascal microscope owned by the Danish Polymer Centre...

  5. Examining Thermally Sprayed Coats By Fluorescence Microscopy

    Science.gov (United States)

    Street, Kenneth W., Jr.; Leonhardt, Todd A.

    1994-01-01

    True flaws distinquished from those induced by preparation of specimens. Fluorescence microscopy reveals debonding, porosity, cracks, and other flaws in specimens of thermally sprayed coating materials. Specimen illuminated, and dye it contains fluoresces, emitting light at different wavelength. Filters emphasize contrast between excitation light and emission light. Specimen viewed directly or photographed on color film.

  6. Effects of playing video games on perceptions of one's humanity.

    Science.gov (United States)

    Greitemeyer, Tobias

    2013-01-01

    According to self-perception theory, individuals infer their characteristics by observing their own behavior. In the present research, the hypothesis is examined whether helping behavior increases perceptions of one's own humanity even when help is given that does not benefit a real person. In fact, two studies revealed that playing a prosocial video game (where the goal is to help and care for other game characters) led to increased perceptions of the player's own humanity (in particular, for positive humanity traits). Results also revealed that playing a violent, relative to a neutral, video game decreased perceptions of humanity on positive humanity traits and increased perceptions of humanity on negative humanity traits. Taken together, it appears that being helpful while playing video games leads to the perception of being more human, whereas being harmful while playing video games leads players to perceive themselves negatively.

  7. Spatial constraints of stereopsis in video displays

    Science.gov (United States)

    Schor, Clifton

    1989-01-01

    Recent development in video technology, such as the liquid crystal displays and shutters, have made it feasible to incorporate stereoscopic depth into the 3-D representations on 2-D displays. However, depth has already been vividly portrayed in video displays without stereopsis using the classical artists' depth cues described by Helmholtz (1866) and the dynamic depth cues described in detail by Ittleson (1952). Successful static depth cues include overlap, size, linear perspective, texture gradients, and shading. Effective dynamic cues include looming (Regan and Beverly, 1979) and motion parallax (Rogers and Graham, 1982). Stereoscopic depth is superior to the monocular distance cues under certain circumstances. It is most useful at portraying depth intervals as small as 5 to 10 arc secs. For this reason it is extremely useful in user-video interactions such as telepresence. Objects can be manipulated in 3-D space, for example, while a person who controls the operations views a virtual image of the manipulated object on a remote 2-D video display. Stereopsis also provides structure and form information in camouflaged surfaces such as tree foliage. Motion parallax also reveals form; however, without other monocular cues such as overlap, motion parallax can yield an ambiguous perception. For example, a turning sphere, portrayed as solid by parallax can appear to rotate either leftward or rightward. However, only one direction of rotation is perceived when stereo-depth is included. If the scene is static, then stereopsis is the principal cue for revealing the camouflaged surface structure. Finally, dynamic stereopsis provides information about the direction of motion in depth (Regan and Beverly, 1979). Clearly there are many spatial constraints, including spatial frequency content, retinal eccentricity, exposure duration, target spacing, and disparity gradient, which - when properly adjusted - can greatly enhance stereodepth in video displays.

  8. VIDEO GAMES CONTRIBUTION TO STUDENTS’ ENTREPRENEURIAL TRAITS AND INTENT

    Directory of Open Access Journals (Sweden)

    Alexandra PERJU-MITRAN

    2014-12-01

    Full Text Available Given the popularity of video games and the influences they may pose on individuals’ psychology and behavior, the present study analyses whether video game playing among university students can be correlated with traits associated with an entrepreneur’s profile, which may, in turn, lead to an entrepreneurial intent. The results of the study reveal that students who do play video games show a higher entrepreneurial intent, this relationship being mediated by several psychological and cognitive characteristics. With regards to the psychological and cognitive factors studied, the results also suggest that a favorable attitude towards playing videogames fosters students’ entrepreneurial potential and has a positive effect on the entrepreneurial intent.

  9. Enhanced video display and navigation for networked streaming video and networked video playlists

    Science.gov (United States)

    Deshpande, Sachin

    2006-01-01

    In this paper we present an automatic enhanced video display and navigation capability for networked streaming video and networked video playlists. Our proposed method uses Synchronized Multimedia Integration Language (SMIL) as presentation language and Real Time Streaming Protocol (RTSP) as network remote control protocol to automatically generate a "enhanced video strip" display for easy navigation. We propose and describe two approaches - a smart client approach and a smart server approach. We also describe a prototype system implementation of our proposed approach.

  10. An Energy-Efficient and High-Quality Video Transmission Architecture in Wireless Video-Based Sensor Networks

    Science.gov (United States)

    Aghdasi, Hadi S.; Abbaspour, Maghsoud; Moghadam, Mohsen Ebrahimi; Samei, Yasaman

    2008-01-01

    Technological progress in the fields of Micro Electro-Mechanical Systems (MEMS) and wireless communications and also the availability of CMOS cameras, microphones and small-scale array sensors, which may ubiquitously capture multimedia content from the field, have fostered the development of low-cost limited resources Wireless Video-based Sensor Networks (WVSN). With regards to the constraints of video-based sensor nodes and wireless sensor networks, a supporting video stream is not easy to implement with the present sensor network protocols. In this paper, a thorough architecture is presented for video transmission over WVSN called Energy-efficient and high-Quality Video transmission Architecture (EQV-Architecture). This architecture influences three layers of communication protocol stack and considers wireless video sensor nodes constraints like limited process and energy resources while video quality is preserved in the receiver side. Application, transport, and network layers are the layers in which the compression protocol, transport protocol, and routing protocol are proposed respectively, also a dropping scheme is presented in network layer. Simulation results over various environments with dissimilar conditions revealed the effectiveness of the architecture in improving the lifetime of the network as well as preserving the video quality. PMID:27873772

  11. Scanning ultrafast electron microscopy.

    Science.gov (United States)

    Yang, Ding-Shyue; Mohammed, Omar F; Zewail, Ahmed H

    2010-08-24

    Progress has been made in the development of four-dimensional ultrafast electron microscopy, which enables space-time imaging of structural dynamics in the condensed phase. In ultrafast electron microscopy, the electrons are accelerated, typically to 200 keV, and the microscope operates in the transmission mode. Here, we report the development of scanning ultrafast electron microscopy using a field-emission-source configuration. Scanning of pulses is made in the single-electron mode, for which the pulse contains at most one or a few electrons, thus achieving imaging without the space-charge effect between electrons, and still in ten(s) of seconds. For imaging, the secondary electrons from surface structures are detected, as demonstrated here for material surfaces and biological specimens. By recording backscattered electrons, diffraction patterns from single crystals were also obtained. Scanning pulsed-electron microscopy with the acquired spatiotemporal resolutions, and its efficient heat-dissipation feature, is now poised to provide in situ 4D imaging and with environmental capability.

  12. Single particle electron microscopy

    NARCIS (Netherlands)

    Boekema, Egbert J.; Folea, Mihaela; Kouril, Roman

    2009-01-01

    Electron microscopy (EM) in combination with image analysis is a powerful technique to study protein structures at low, medium, and high resolution. Since electron micrographs of biological objects are very noisy, improvement of the signal-to-noise ratio by image processing is an integral part of

  13. and transmission electron microscopy

    African Journals Online (AJOL)

    Administrator

    immune-electron microscopy (IEM) from patients' feces. They reported this virus particle as the causative agent of winter vomiting outbreaks in Norwalk (Kapikian et al.,. 1972). This is the remarkable landmark study of non- bacterial gastroenteritis viruses, especially for small round structured viruses (SRSVs). After that, many.

  14. Atomic Force Microscopy

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 15; Issue 7. Atomic Force Microscopy - A Tool to Unveil the Mystery of Biological Systems ... Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 ...

  15. Photoacoustic computed microscopy

    Science.gov (United States)

    Yao, Lei; Xi, Lei; Jiang, Huabei

    2014-05-01

    Photoacoustic microscopy (PAM) is emerging as a powerful technique for imaging microvasculature at depths beyond the ~1 mm depth limit associated with confocal microscopy, two-photon microscopy and optical coherence tomography. PAM, however, is currently qualitative in nature and cannot quantitatively measure important functional parameters including oxyhemoglobin (HbO2), deoxyhemoglobin (HbR), oxygen saturation (sO2), blood flow (BF) and rate of oxygen metabolism (MRO2). Here we describe a new photoacoustic microscopic method, termed photoacoustic computed microscopy (PACM) that combines current PAM technique with a model-based inverse reconstruction algorithm. We evaluate the PACM approach using tissue-mimicking phantoms and demonstrate its in vivo imaging ability of quantifying HbO2, HbR, sO2, cerebral BF and cerebral MRO2 at the small vessel level in a rodent model. This new technique provides a unique tool for neuroscience research and for visualizing microvasculature dynamics involved in tumor angiogenesis and in inflammatory joint diseases.

  16. Magnetic Force Microscopy

    NARCIS (Netherlands)

    Abelmann, Leon

    Principle of MFM In magnetic force microscopy (MFM), the magnetic stray field above a very flat specimen, or sample, is detected by placing a small magnetic element, the tip, mounted on a cantilever spring very close to the surface of the sample (Figure 1). Typical dimensions are a cantilever length

  17. Digital Video Teach Yourself VISUALLY

    CERN Document Server

    Watson, Lonzell

    2010-01-01

    Tips and techniques for shooting and sharing superb digital videos. Never before has video been more popular-or more accessible to the home photographer. Now you can create YouTube-worthy, professional-looking video, with the help of this richly illustrated guide. In a straightforward, simple, highly visual format, Teach Yourself VISUALLY Digital Video demystifies the secrets of great video. With colorful screenshots and illustrations plus step-by-step instructions, the book explains the features of your camera and their capabilities, and shows you how to go beyond "auto" to manually

  18. Representing videos in tangible products

    Science.gov (United States)

    Fageth, Reiner; Weiting, Ralf

    2014-03-01

    Videos can be taken with nearly every camera, digital point and shoot cameras, DSLRs as well as smartphones and more and more with so-called action cameras mounted on sports devices. The implementation of videos while generating QR codes and relevant pictures out of the video stream via a software implementation was contents in last years' paper. This year we present first data about what contents is displayed and how the users represent their videos in printed products, e.g. CEWE PHOTOBOOKS and greeting cards. We report the share of the different video formats used, the number of images extracted out of the video in order to represent the video, the positions in the book and different design strategies compared to regular books.

  19. Candida albicans morphologies revealed by scanning electron microscopy analysis

    Directory of Open Access Journals (Sweden)

    M. Staniszewska

    2013-09-01

    Full Text Available Scanning electron microscope (SEM observations were used to analyze particular morphologies of Candida albicans clinical isolate (strain 82 and mutants defective in hyphae-promoting genes EFG1 (strain HLC52 and/ or CPH1 (strains HLC54 and Can16. Transcription factors Efg1 and Cph1 play role in regulating filamentation and adhesion of C. albicans' morphologies. Comparative analysis of such mutants and clinical isolate showed that Efg1 is required for human serum-induced cell growth and morphological switching. In the study, distinct differences between ultrastructural patterns of clinical strain's and null mutants' morphologies were observed (spherical vs tube-like blastoconidia, or solid and fragile constricted septa vs only the latter observed in strains with EFG1 deleted. In addition, wild type strain displayed smooth colonies of cells in comparison to mutants which exhibited wrinkled phenotype. It was observed that blastoconidia of clinical strain exhibited either polarly or randomly located budding. Contrariwise, morphotypes of mutants showed either multiple polar budding or a centrally located single bud scar (mother-daughter cell junction distinguishing tube-like yeast/ pseudohyphal growth (the length-to-width ratios larger than 1.5. In their planktonic form of growth, blastoconidia of clinical bloodstream isolate formed constitutively true hyphae under undiluted human serum inducing conditions. It was found that true hyphae are essential elements for developing structural integrity of conglomerate, as mutants displaying defects in their flocculation and conglomerate-forming abilities in serum. While filamentation is an important virulence trait in C. albicans the true hyphae are the morphologies which may be expected to play a role in bloodstream infections.

  20. Geotail Video News Release

    Science.gov (United States)

    1992-01-01

    The Geotail mission, part of the International Solar Terrestrial Physics (ISTP) program, measures global energy flow and transformation in the magnetotail to increase understanding of fundamental magnetospheric processes. The satellite was launched on July 24, 1992 onboard a Delta II rocket. This video shows with animation the solar wind, and its effect on the Earth. The narrator explains that the Geotail spacecraft was designed and built by the Institute of Space and Astronautical Science (ISAS), the Japanese Space Agency. The mission objectives are reviewed by one of the scientist in a live view. The video also shows an animation of the orbit, while the narrator explains the orbit and the reason for the small launch window.

  1. CARACTERIZACION VOZ Y VIDEO

    Directory of Open Access Journals (Sweden)

    Octavio José Salcedo Parra

    2011-11-01

    Full Text Available La motivación para caracterizar el tráfico de voz y video está en la necesidad de las empresas proveedoras de servicio en mantener redes de transporte de información con capacidades acordes a los requerimientos de los usuarios.  Poder determinar en forma oportuna como los elementos técnicos que hacen parte de las redes afectan su desempeño, teniendo en cuenta que cada tipo de servicio es afectado en mayor o menor medida por dichos elementos dentro de los que tenemos el jitter, las demoras y las pérdidas de paquetes entre otros. El presente trabajo muestra varios casos de caracterización de tráfico tanto de voz como de video en las que se utilizan una diversidad de técnicas para diferentes tipos de servicio.

  2. Video Pulses: User-Based Modeling of Interesting Video Segments

    Directory of Open Access Journals (Sweden)

    Markos Avlonitis

    2014-01-01

    Full Text Available We present a user-based method that detects regions of interest within a video in order to provide video skims and video summaries. Previous research in video retrieval has focused on content-based techniques, such as pattern recognition algorithms that attempt to understand the low-level features of a video. We are proposing a pulse modeling method, which makes sense of a web video by analyzing users' Replay interactions with the video player. In particular, we have modeled the user information seeking behavior as a time series and the semantic regions as a discrete pulse of fixed width. Then, we have calculated the correlation coefficient between the dynamically detected pulses at the local maximums of the user activity signal and the pulse of reference. We have found that users' Replay activity significantly matches the important segments in information-rich and visually complex videos, such as lecture, how-to, and documentary. The proposed signal processing of user activity is complementary to previous work in content-based video retrieval and provides an additional user-based dimension for modeling the semantics of a social video on the web.

  3. ELECTRON MICROSCOPY OF RHODOTORULA GLUTINIS

    Science.gov (United States)

    Thyagarajan, T. R.; Conti, S. F.; Naylor, H. B.

    1962-01-01

    Thyagarajan, T. R. (Dartmouth Medical School, Hanover, N. H.), S. F. Conti, and H. B. Naylor. Electron microscopy of Rhodotorula glutinis. J. Bacteriol. 83:381–394. 1962.—The structure and manner of nuclear division in Rhodotorula glutinis was studied by electron microscopy of ultrathin sections. Parallel studies with the light microscope, employing conventional staining techniques and phase-contrast microscope observations on nuclei in living cells, were carried out. The nucleus is spherical to oval and is bounded by a nuclear membrane. Intranuclear structures, identified as nucleoli, and electron-transparent areas were observed. The nuclear membrane persists throughout the various stages of cell division. Observations of the nucleus with the electron microscope revealed that nuclear division occurs by a process of elongation and constriction similar to that seen in both living and stained cells. The fine structure of mitochondria and other components of the yeast cell and their behavior during cell division are described. The absence of vacuoles in actively dividing cells of Rhodotorula glutinis lends further support to the view that the vacuole is not an integral part of the nucleus. The results with the electron microscope generally support and considerably extend those obtained with living and stained cells. Images PMID:13921132

  4. Solid state video cameras

    CERN Document Server

    Cristol, Y

    2013-01-01

    Solid State Video Cameras reviews the state of the art in the field of solid-state television cameras as compiled from patent literature. Organized into 10 chapters, the book begins with the basic array types of solid-state imagers and appropriate read-out circuits and methods. Documents relating to improvement of picture quality, such as spurious signal suppression, uniformity correction, or resolution enhancement, are also cited. The last part considerssolid-state color cameras.

  5. The video lecture

    OpenAIRE

    Crook, Charles; Schofield, Louise

    2017-01-01

    Vocabulary for describing the structures, roles, and relationships characteristic of traditional, or ‘offline’, education has been seamlessly applied to the designs of ‘online’ education. One example is the lecture, delivered as a video recording. The purpose of this research is to consider the concept of ‘lecture’ as realised in both offline and online contexts. We explore how media differences entail different student experiences and how these differences relate to design decisions associat...

  6. The Future of Video

    OpenAIRE

    Li, F.

    2016-01-01

    Executive Summary \\ud \\ud A range of technological innovations (e.g. smart phones and digital cameras), infrastructural advances (e.g. broadband and 3G/4G wireless networks) and platform developments (e.g. YouTube, Facebook, Snapchat, Instagram, Amazon, and Netflix) are collectively transforming the way video is produced, distributed, consumed, archived – and importantly, monetised. Changes have been observed well beyond the mainstream TV and film industries, and these changes are increasingl...

  7. Video time encoding machines.

    Science.gov (United States)

    Lazar, Aurel A; Pnevmatikakis, Eftychios A

    2011-03-01

    We investigate architectures for time encoding and time decoding of visual stimuli such as natural and synthetic video streams (movies, animation). The architecture for time encoding is akin to models of the early visual system. It consists of a bank of filters in cascade with single-input multi-output neural circuits. Neuron firing is based on either a threshold-and-fire or an integrate-and-fire spiking mechanism with feedback. We show that analog information is represented by the neural circuits as projections on a set of band-limited functions determined by the spike sequence. Under Nyquist-type and frame conditions, the encoded signal can be recovered from these projections with arbitrary precision. For the video time encoding machine architecture, we demonstrate that band-limited video streams of finite energy can be faithfully recovered from the spike trains and provide a stable algorithm for perfect recovery. The key condition for recovery calls for the number of neurons in the population to be above a threshold value.

  8. Robotic video photogrammetry system

    Science.gov (United States)

    Gustafson, Peter C.

    1997-07-01

    For many years, photogrammetry has been in use at TRW. During that time, needs have arisen for highly repetitive measurements. In an effort to satisfy these needs in a timely manner, a specialized Robotic Video Photogrammetry System (RVPS) was developed by TRW in conjunction with outside vendors. The primary application for the RVPS has strict accuracy requirements that demand significantly more images than the previously used film-based system. The time involved in taking these images was prohibitive but by automating the data acquisition process, video techniques became a practical alternative to the more traditional film- based approach. In fact, by applying video techniques, measurement productivity was enhanced significantly. Analysis involved was also brought `on-board' to the RVPS, allowing shop floor acquisition and delivery of results. The RVPS has also been applied in other tasks and was found to make a critical improvement in productivity, allowing many more tests to be run in a shorter time cycle. This paper will discuss the creation of the system and TRW's experiences with the RVPS. Highlighted will be the lessons learned during these efforts and significant attributes of the process not common to the standard application of photogrammetry for industrial measurement. As productivity and ease of use continue to drive the application of photogrammetry in today's manufacturing climate, TRW expects several systems, with technological improvements applied, to be in use in the near future.

  9. Utilizing Video Games

    Science.gov (United States)

    Blaize, L.

    Almost from its birth, the computer and video gaming industry has done an admirable job of communicating the vision and attempting to convey the experience of traveling through space to millions of gamers from all cultures and demographics. This paper will propose several approaches the 100 Year Starship Study can take to use the power of interactive media to stir interest in the Starship and related projects among a global population. It will examine successful gaming franchises from the past that are relevant to the mission and consider ways in which the Starship Study could cooperate with game development studios to bring the Starship vision to those franchises and thereby to the public. The paper will examine ways in which video games can be used to crowd-source research aspects for the Study, and how video games are already considering many of the same topics that will be examined by this Study. Finally, the paper will propose some mechanisms by which the 100 Year Starship Study can establish very close ties with the gaming industry and foster cooperation in pursuit of the Study's goals.

  10. Polarized Light Microscopy

    Science.gov (United States)

    Frandsen, Athela F.

    2016-01-01

    Polarized light microscopy (PLM) is a technique which employs the use of polarizing filters to obtain substantial optical property information about the material which is being observed. This information can be combined with other microscopy techniques to confirm or elucidate the identity of an unknown material, determine whether a particular contaminant is present (as with asbestos analysis), or to provide important information that can be used to refine a manufacturing or chemical process. PLM was the major microscopy technique in use for identification of materials for nearly a century since its introduction in 1834 by William Fox Talbot, as other techniques such as SEM (Scanning Electron Microscopy), FTIR (Fourier Transform Infrared spectroscopy), XPD (X-ray Powder Diffraction), and TEM (Transmission Electron Microscopy) had not yet been developed. Today, it is still the only technique approved by the Environmental Protection Agency (EPA) for asbestos analysis, and is often the technique first applied for identification of unknown materials. PLM uses different configurations in order to determine different material properties. With each configuration additional clues can be gathered, leading to a conclusion of material identity. With no polarizing filter, the microscope can be used just as a stereo optical microscope, and view qualities such as morphology, size, and number of phases. With a single polarizing filter (single polars), additional properties can be established, such as pleochroism, individual refractive indices, and dispersion staining. With two polarizing filters (crossed polars), even more can be deduced: isotropy vs. anisotropy, extinction angle, birefringence/degree of birefringence, sign of elongation, and anomalous polarization colors, among others. With the use of PLM many of these properties can be determined in a matter of seconds, even for those who are not highly trained. McCrone, a leader in the field of polarized light microscopy, often

  11. Light Sheet Fluorescence Microscopy

    Science.gov (United States)

    Santi, Peter A.

    2011-01-01

    Light sheet fluorescence microscopy (LSFM) functions as a non-destructive microtome and microscope that uses a plane of light to optically section and view tissues with subcellular resolution. This method is well suited for imaging deep within transparent tissues or within whole organisms, and because tissues are exposed to only a thin plane of light, specimen photobleaching and phototoxicity are minimized compared to wide-field fluorescence, confocal, or multiphoton microscopy. LSFMs produce well-registered serial sections that are suitable for three-dimensional reconstruction of tissue structures. Because of a lack of a commercial LSFM microscope, numerous versions of light sheet microscopes have been constructed by different investigators. This review describes development of the technology, reviews existing devices, provides details of one LSFM device, and shows examples of images and three-dimensional reconstructions of tissues that were produced by LSFM. PMID:21339178

  12. Video Analysis: Lessons from Professional Video Editing Practice

    Directory of Open Access Journals (Sweden)

    Eric Laurier

    2008-09-01

    Full Text Available In this paper we join a growing body of studies that learn from vernacular video analysts quite what video analysis as an intelligible course of action might be. Rather than pursuing epistemic questions regarding video as a number of other studies of video analysis have done, our concern here is with the crafts of producing the filmic. As such we examine how audio and video clips are indexed and brought to hand during the logging process, how a first assembly of the film is built at the editing bench and how logics of shot sequencing relate to wider concerns of plotting, genre and so on. In its conclusion we make a number of suggestions about the future directions of studying video and film editors at work. URN: urn:nbn:de:0114-fqs0803378

  13. Deep Learning Microscopy

    KAUST Repository

    Rivenson, Yair

    2017-05-12

    We demonstrate that a deep neural network can significantly improve optical microscopy, enhancing its spatial resolution over a large field-of-view and depth-of-field. After its training, the only input to this network is an image acquired using a regular optical microscope, without any changes to its design. We blindly tested this deep learning approach using various tissue samples that are imaged with low-resolution and wide-field systems, where the network rapidly outputs an image with remarkably better resolution, matching the performance of higher numerical aperture lenses, also significantly surpassing their limited field-of-view and depth-of-field. These results are transformative for various fields that use microscopy tools, including e.g., life sciences, where optical microscopy is considered as one of the most widely used and deployed techniques. Beyond such applications, our presented approach is broadly applicable to other imaging modalities, also spanning different parts of the electromagnetic spectrum, and can be used to design computational imagers that get better and better as they continue to image specimen and establish new transformations among different modes of imaging.

  14. Surveillance Video Synopsis in GIS

    Directory of Open Access Journals (Sweden)

    Yujia Xie

    2017-10-01

    Full Text Available Surveillance videos contain a considerable amount of data, wherein interesting information to the user is sparsely distributed. Researchers construct video synopsis that contain key information extracted from a surveillance video for efficient browsing and analysis. Geospatial–temporal information of a surveillance video plays an important role in the efficient description of video content. Meanwhile, current approaches of video synopsis lack the introduction and analysis of geospatial-temporal information. Owing to the preceding problems mentioned, this paper proposes an approach called “surveillance video synopsis in GIS”. Based on an integration model of video moving objects and GIS, the virtual visual field and the expression model of the moving object are constructed by spatially locating and clustering the trajectory of the moving object. The subgraphs of the moving object are reconstructed frame by frame in a virtual scene. Results show that the approach described in this paper comprehensively analyzed and created fusion expression patterns between video dynamic information and geospatial–temporal information in GIS and reduced the playback time of video content.

  15. Smartphone-based Video of Demodex folliculorum In Biopsied Human Eyelash Follicles.

    Science.gov (United States)

    Vahedi, Mithaq; Davis, Gavin; Coleman, Michael James; Garrett, Brian Steven; Eghrari, Allen Omid

    2015-01-01

    The ability of smartphone technology to document static microscopy images has been well documented and is gaining widespread use in ophthalmology, where slit-lamp biomicroscopy is frequently utilized. However, little has been described regarding the use of smartphone technology to relay video of tissue microscopy results to patients, particularly when a tissue sample integrates motility of organisms as a characteristic feature of the disease. Here, we describe the method to use smartphone video to document motility of Demodex folliculorum in human eyelashes, individual results of which can be shown to patients for education and counseling purposes. The use of smartphone video in documenting the motility of organisms may prove to be beneficial in a variety of medical fields; producers of electronic medical records, therefore, may find it helpful to integrate video drop box tools.

  16. Smartphone-based Video of Demodex folliculorum In Biopsied Human Eyelash Follicles

    Science.gov (United States)

    Vahedi, Mithaq; Davis, Gavin; Coleman, Michael James; Garrett, Brian Steven; Eghrari, Allen Omid

    2015-01-01

    The ability of smartphone technology to document static microscopy images has been well documented and is gaining widespread use in ophthalmology, where slit-lamp biomicroscopy is frequently utilized. However, little has been described regarding the use of smartphone technology to relay video of tissue microscopy results to patients, particularly when a tissue sample integrates motility of organisms as a characteristic feature of the disease. Here, we describe the method to use smartphone video to document motility of Demodex folliculorum in human eyelashes, individual results of which can be shown to patients for education and counseling purposes. The use of smartphone video in documenting the motility of organisms may prove to be beneficial in a variety of medical fields; producers of electronic medical records, therefore, may find it helpful to integrate video drop box tools. PMID:26060828

  17. Recognizing problem video game use.

    Science.gov (United States)

    Porter, Guy; Starcevic, Vladan; Berle, David; Fenech, Pauline

    2010-02-01

    It has been increasingly recognized that some people develop problem video game use, defined here as excessive use of video games resulting in various negative psychosocial and/or physical consequences. The main objectives of the present study were to identify individuals with problem video game use and compare them with those without problem video game use on several variables. An international, anonymous online survey was conducted, using a questionnaire with provisional criteria for problem video game use, which the authors have developed. These criteria reflect the crucial features of problem video game use: preoccupation with and loss of control over playing video games and multiple adverse consequences of this activity. A total of 1945 survey participants completed the survey. Respondents who were identified as problem video game users (n = 156, 8.0%) differed significantly from others (n = 1789) on variables that provided independent, preliminary validation of the provisional criteria for problem video game use. They played longer than planned and with greater frequency, and more often played even though they did not want to and despite believing that they should not do it. Problem video game users were more likely to play certain online role-playing games, found it easier to meet people online, had fewer friends in real life, and more often reported excessive caffeine consumption. People with problem video game use can be identified by means of a questionnaire and on the basis of the present provisional criteria, which require further validation. These findings have implications for recognition of problem video game users among individuals, especially adolescents, who present to mental health services. Mental health professionals need to acknowledge the public health significance of the multiple negative consequences of problem video game use.

  18. Nuclear magnetic resonance force microscopy at millikelvin temperatures

    NARCIS (Netherlands)

    Haan, Arthur Mattheus Johannes den

    2016-01-01

    Nuclear magnetic resonance force microscopy (MRFM) is a technique which combines magnetic resonance imaging (MRI) with scanning probe microscopy (SPM). The final goal is to develop this technique to such a level that the atomic structure of a virus or protein can be revealed by this microscope. This

  19. High Definition Video Streaming Using H.264 Video Compression

    OpenAIRE

    Bechqito, Yassine

    2009-01-01

    This thesis presents high definition video streaming using H.264 codec implementation. The experiment carried out in this study was done for an offline streaming video but a model for live high definition streaming is introduced, as well. Prior to the actual experiment, this study describes digital media streaming. Also, the different technologies involved in video streaming are covered. These include streaming architecture and a brief overview on H.264 codec as well as high definition t...

  20. Video Quality Prediction over Wireless 4G

    KAUST Repository

    Lau, Chun Pong

    2013-04-14

    In this paper, we study the problem of video quality prediction over the wireless 4G network. Video transmission data is collected from a real 4G SCM testbed for investigating factors that affect video quality. After feature transformation and selection on video and network parameters, video quality is predicted by solving as regression problem. Experimental results show that the dominated factor on video quality is the channel attenuation and video quality can be well estimated by our models with small errors.

  1. Rate-Adaptive Video Compression (RAVC) Universal Video Stick (UVS)

    Science.gov (United States)

    Hench, David L.

    2009-05-01

    The H.264 video compression standard, aka MPEG 4 Part 10 aka Advanced Video Coding (AVC) allows new flexibility in the use of video in the battlefield. This standard necessitates encoder chips to effectively utilize the increased capabilities. Such chips are designed to cover the full range of the standard with designers of individual products given the capability of selecting the parameters that differentiate a broadcast system from a video conferencing system. The SmartCapture commercial product and the Universal Video Stick (UVS) military versions are about the size of a thumb drive with analog video input and USB (Universal Serial Bus) output and allow the user to select the parameters of imaging to the. Thereby, allowing the user to select video bandwidth (and video quality) using four dimensions of quality, on the fly, without stopping video transmission. The four dimensions are: 1) spatial, change from 720 pixel x 480 pixel to 320 pixel x 360 pixel to 160 pixel x 180 pixel, 2) temporal, change from 30 frames/ sec to 5 frames/sec, 3) transform quality with a 5 to 1 range, 4) and Group of Pictures (GOP) that affects noise immunity. The host processor simply wraps the H.264 network abstraction layer packets into the appropriate network packets. We also discuss the recently adopted scalable amendment to H.264 that will allow limit RAVC at any point in the communication chain by throwing away preselected packets.

  2. Video Tracking dalam Digital Compositing untuk Paska Produksi Video

    Directory of Open Access Journals (Sweden)

    Ardiyan Ardiyan

    2012-04-01

    Full Text Available Video Tracking is one of the processes in video postproduction and motion picture digitally. The ability of video tracking method in the production is helpful to realize the concept of the visual. It is considered in the process of visual effects making. This paper presents how the tracking process and its benefits in visual needs, especially for video and motion picture production. Some of the things involved in the process of tracking such as failure to do so are made clear in this discussion. 

  3. Video – ned med overliggeren

    DEFF Research Database (Denmark)

    Langebæk, Rikke

    2010-01-01

    Århus – nov 2010 ’Podcast og Video i Undervisningen’ Video – helt ned på jorden Rikke Langebæk, DVM, Phd-studerende, Seniordyrlæge, Institut for Mindre Husdyrs Sygdomme, LIFE, KU Anvendelsen af video i undervisningen har mange iøjnefaldende fordele, og der er nok mange, der drømmer om at implemen......Århus – nov 2010 ’Podcast og Video i Undervisningen’ Video – helt ned på jorden Rikke Langebæk, DVM, Phd-studerende, Seniordyrlæge, Institut for Mindre Husdyrs Sygdomme, LIFE, KU Anvendelsen af video i undervisningen har mange iøjnefaldende fordele, og der er nok mange, der drømmer om...

  4. Robust Watermarking of Video Streams

    Directory of Open Access Journals (Sweden)

    T. Polyák

    2006-01-01

    Full Text Available In the past few years there has been an explosion in the use of digital video data. Many people have personal computers at home, and with the help of the Internet users can easily share video files on their computer. This makes possible the unauthorized use of digital media, and without adequate protection systems the authors and distributors have no means to prevent it.Digital watermarking techniques can help these systems to be more effective by embedding secret data right into the video stream. This makes minor changes in the frames of the video, but these changes are almost imperceptible to the human visual system. The embedded information can involve copyright data, access control etc. A robust watermark is resistant to various distortions of the video, so it cannot be removed without affecting the quality of the host medium. In this paper I propose a video watermarking scheme that fulfills the requirements of a robust watermark. 

  5. Single-molecule fluorescence microscopy in living Caenorhabditis elegans

    NARCIS (Netherlands)

    van Krugten, Jaap; Peterman, Erwin J.G.

    2018-01-01

    Transportation of organelles and biomolecules is vital for many cellular processes. Single-molecule (SM) fluorescence microscopy can expose molecular aspects of the dynamics that remain unresolved in ensemble experiments. For example, trajectories of individual, moving biomolecules can reveal

  6. Ferritin protein imaging and detection by magnetic force microscopy.

    Science.gov (United States)

    Hsieh, Chiung-Wen; Zheng, Bin; Hsieh, Shuchen

    2010-03-14

    Magnetic force microscopy was used to image and detect ferritin proteins and the strength of the magnetic signal is discussed, revealing a large workable lift height between the magnetic tip and the ferritin sample.

  7. Video Games and Adolescent Fighting

    OpenAIRE

    Ward, Michael R.

    2010-01-01

    Psychologists have found positive correlations between playing violent video games and violent and antisocial attitudes. However, these studies typically do not control for other covariates, particularly sex, that are known to be associated with both video game play and aggression. This study exploits the Youth Risk Behavior Survey, which includes questions on video game play and fighting as well as basic demographic information. With both parametric and nonparametric estimators, as there is ...

  8. Women as Video Game Consumers

    OpenAIRE

    Kiviranta, Hanna

    2017-01-01

    The purpose of this Thesis is to study women as video game consumers through the games that they play. This was done by case studies on the content of five video games from genres that statistically are popular amongst women. To introduce the topic and to build the theoretical framework, the key terms and the video game industry are introduced. The reader is acquainted with theories on consumer behaviour, buying processes and factors that influence our consuming habits. These aspects are...

  9. Quality scalable video data stream

    OpenAIRE

    Wiegand, T.; Kirchhoffer, H.; Schwarz, H

    2008-01-01

    An apparatus for generating a quality-scalable video data stream (36) is described which comprises means (42) for coding a video signal (18) using block-wise transformation to obtain transform blocks (146, 148) of transformation coefficient values for a picture (140) of the video signal, a predetermined scan order (154, 156, 164, 166) with possible scan positions being defined among the transformation coefficient values within the transform blocks so that in each transform block, for each pos...

  10. Applications of microscopy in Salmonella research.

    Science.gov (United States)

    Malt, Layla M; Perrett, Charlotte A; Humphrey, Suzanne; Jepson, Mark A

    2015-01-01

    Salmonella enterica is a Gram-negative enteropathogen that can cause localized infections, typically resulting in gastroenteritis, or systemic infection, e.g., typhoid fever, in humans and many other animals. Understanding the mechanisms by which Salmonella induces disease has been the focus of intensive research. This has revealed that Salmonella invasion requires dynamic cross-talk between the microbe and host cells, in which bacterial adherence rapidly leads to a complex sequence of cellular responses initiated by proteins translocated into the host cell by a type 3 secretion system. Once these Salmonella-induced responses have resulted in bacterial invasion, proteins translocated by a second type 3 secretion system initiate further modulation of cellular activities to enable survival and replication of the invading pathogen. Elucidation of the complex and highly dynamic pathogen-host interactions ultimately requires analysis at the level of single cells and single infection events. To achieve this goal, researchers have applied a diverse range of microscopy techniques to analyze Salmonella infection in models ranging from whole animal to isolated cells and simple eukaryotic organisms. For example, electron microscopy and high-resolution light microscopy techniques such as confocal microscopy can reveal the precise location of Salmonella and its relationship to cellular components. Widefield light microscopy is a simpler approach with which to study the interaction of bacteria with host cells and often has advantages for live cell imaging, enabling detailed analysis of the dynamics of infection and cellular responses. Here we review the use of imaging techniques in Salmonella research and compare the capabilities of different classes of microscope to address specific types of research question. We also provide protocols and notes on some microscopy techniques used routinely in our own research.

  11. Port Video and Logo

    OpenAIRE

    Whitehead, Stuart; Rush, Joshua

    2013-01-01

    Logo PDF files should be accessible by any PDF reader such as Adobe Reader. SVG files of the logo are vector graphics accessible by programs such as Inkscape or Adobe Illustrator. PNG files are image files of the logo that should be able to be opened by any operating system's default image viewer. The final report is submitted in both .doc (Microsoft Word) and .pdf formats. The video is submitted in .avi format and can be viewed with Windows Media Player or VLC. Audio .wav files are also ...

  12. Video, videoarte, iconoclasmo

    OpenAIRE

    Roncallo Dow, Sergio; Universidad de la Sabana

    2013-01-01

    El propósito de este artículo es realizar un acercamiento a la forma-video y al videoarte desde una perspectiva estética. Para ello, en un primer momento, se hace una reflexión a propósito del estatuto de la imagen en occidente buscado evidenciar su carácter oscuro y el temor que parece haber suscitado desde siempre. Este punto se trabaja sobre algunos postulados platónicos que nos llevan a pensar un posible camino de la superación del iconoclasmo a través del surrealismo, el cine y la fotogr...

  13. Intellectual Video Filming

    DEFF Research Database (Denmark)

    Juel, Henrik

    Like everyone else university students of the humanities are quite used to watching Hollywood productions and professional TV. It requires some didactic effort to redirect their eyes and ears away from the conventional mainstream style and on to new and challenging ways of using the film media...... in favour of worthy causes. However, it is also very rewarding to draw on the creativity, enthusiasm and rapidly improving technical skills of young students, and to guide them to use video equipment themselves for documentary, for philosophical film essays and intellectual debate. In the digital era...

  14. An Energy-Efficient and High-Quality Video Transmission Architecture in Wireless Video-Based Sensor Networks

    Directory of Open Access Journals (Sweden)

    Yasaman Samei

    2008-08-01

    Full Text Available Technological progress in the fields of Micro Electro-Mechanical Systems (MEMS and wireless communications and also the availability of CMOS cameras, microphones and small-scale array sensors, which may ubiquitously capture multimedia content from the field, have fostered the development of low-cost limited resources Wireless Video-based Sensor Networks (WVSN. With regards to the constraints of videobased sensor nodes and wireless sensor networks, a supporting video stream is not easy to implement with the present sensor network protocols. In this paper, a thorough architecture is presented for video transmission over WVSN called Energy-efficient and high-Quality Video transmission Architecture (EQV-Architecture. This architecture influences three layers of communication protocol stack and considers wireless video sensor nodes constraints like limited process and energy resources while video quality is preserved in the receiver side. Application, transport, and network layers are the layers in which the compression protocol, transport protocol, and routing protocol are proposed respectively, also a dropping scheme is presented in network layer. Simulation results over various environments with dissimilar conditions revealed the effectiveness of the architecture in improving the lifetime of the network as well as preserving the video quality.

  15. An Energy-Efficient and High-Quality Video Transmission Architecture in Wireless Video-Based Sensor Networks.

    Science.gov (United States)

    Aghdasi, Hadi S; Abbaspour, Maghsoud; Moghadam, Mohsen Ebrahimi; Samei, Yasaman

    2008-08-04

    Technological progress in the fields of Micro Electro-Mechanical Systems (MEMS) and wireless communications and also the availability of CMOS cameras, microphones and small-scale array sensors, which may ubiquitously capture multimedia content from the field, have fostered the development of low-cost limited resources Wireless Video-based Sensor Networks (WVSN). With regards to the constraints of videobased sensor nodes and wireless sensor networks, a supporting video stream is not easy to implement with the present sensor network protocols. In this paper, a thorough architecture is presented for video transmission over WVSN called Energy-efficient and high-Quality Video transmission Architecture (EQV-Architecture). This architecture influences three layers of communication protocol stack and considers wireless video sensor nodes constraints like limited process and energy resources while video quality is preserved in the receiver side. Application, transport, and network layers are the layers in which the compression protocol, transport protocol, and routing protocol are proposed respectively, also a dropping scheme is presented in network layer. Simulation results over various environments with dissimilar conditions revealed the effectiveness of the architecture in improving the lifetime of the network as well as preserving the video quality.

  16. Video game characteristics, happiness and flow as predictors of addiction among video game players: A pilot study.

    Science.gov (United States)

    Hull, Damien C; Williams, Glenn A; Griffiths, Mark D

    2013-09-01

    Video games provide opportunities for positive psychological experiences such as flow-like phenomena during play and general happiness that could be associated with gaming achievements. However, research has shown that specific features of game play may be associated with problematic behaviour associated with addiction-like experiences. The study was aimed at analysing whether certain structural characteristics of video games, flow, and global happiness could be predictive of video game addiction. A total of 110 video game players were surveyed about a game they had recently played by using a 24-item checklist of structural characteristics, an adapted Flow State Scale, the Oxford Happiness Questionnaire, and the Game Addiction Scale. The study revealed decreases in general happiness had the strongest role in predicting increases in gaming addiction. One of the nine factors of the flow experience was a significant predictor of gaming addiction - perceptions of time being altered during play. The structural characteristic that significantly predicted addiction was its social element with increased sociability being associated with higher levels of addictive-like experiences. Overall, the structural characteristics of video games, elements of the flow experience, and general happiness accounted for 49.2% of the total variance in Game Addiction Scale levels. Implications for interventions are discussed, particularly with regard to making players more aware of time passing and in capitalising on benefits of social features of video game play to guard against addictive-like tendencies among video game players.

  17. Bacterial adhesion force quantification by fluidic force microscopy

    Science.gov (United States)

    Potthoff, Eva; Ossola, Dario; Zambelli, Tomaso; Vorholt, Julia A.

    2015-02-01

    Quantification of detachment forces between bacteria and substrates facilitates the understanding of the bacterial adhesion process that affects cell physiology and survival. Here, we present a method that allows for serial, single bacterial cell force spectroscopy by combining the force control of atomic force microscopy with microfluidics. Reversible bacterial cell immobilization under physiological conditions on the pyramidal tip of a microchanneled cantilever is achieved by underpressure. Using the fluidic force microscopy technology (FluidFM), we achieve immobilization forces greater than those of state-of-the-art cell-cantilever binding as demonstrated by the detachment of Escherichia coli from polydopamine with recorded forces between 4 and 8 nN for many cells. The contact time and setpoint dependence of the adhesion forces of E. coli and Streptococcus pyogenes, as well as the sequential detachment of bacteria out of a chain, are shown, revealing distinct force patterns in the detachment curves. This study demonstrates the potential of the FluidFM technology for quantitative bacterial adhesion measurements of cell-substrate and cell-cell interactions that are relevant in biofilms and infection biology.Quantification of detachment forces between bacteria and substrates facilitates the understanding of the bacterial adhesion process that affects cell physiology and survival. Here, we present a method that allows for serial, single bacterial cell force spectroscopy by combining the force control of atomic force microscopy with microfluidics. Reversible bacterial cell immobilization under physiological conditions on the pyramidal tip of a microchanneled cantilever is achieved by underpressure. Using the fluidic force microscopy technology (FluidFM), we achieve immobilization forces greater than those of state-of-the-art cell-cantilever binding as demonstrated by the detachment of Escherichia coli from polydopamine with recorded forces between 4 and 8 nN for many

  18. CHARACTER RECOGNITION OF VIDEO SUBTITLES\\

    Directory of Open Access Journals (Sweden)

    Satish S Hiremath

    2016-11-01

    Full Text Available An important task in content based video indexing is to extract text information from videos. The challenges involved in text extraction and recognition are variation of illumination on each video frame with text, the text present on the complex background and different font size of the text. Using various image processing algorithms like morphological operations, blob detection and histogram of oriented gradients the character recognition of video subtitles is implemented. Segmentation, feature extraction and classification are the major steps of character recognition. Several experimental results are shown to demonstrate the performance of the proposed algorithm

  19. ABOUT SOUNDS IN VIDEO GAMES

    Directory of Open Access Journals (Sweden)

    Denikin Anton A.

    2012-12-01

    Full Text Available The article considers the aesthetical and practical possibilities for sounds (sound design in video games and interactive applications. Outlines the key features of the game sound, such as simulation, representativeness, interactivity, immersion, randomization, and audio-visuality. The author defines the basic terminology in study of game audio, as well as identifies significant aesthetic differences between film sounds and sounds in video game projects. It is an attempt to determine the techniques of art analysis for the approaches in study of video games including aesthetics of their sounds. The article offers a range of research methods, considering the video game scoring as a contemporary creative practice.

  20. VIDEO BLOGGING AND ENGLISH PRESENTATION PERFORMANCE: A PILOT STUDY.

    Science.gov (United States)

    Alan Hung, Shao-Ting; Danny Huang, Heng-Tsung

    2015-10-01

    This study investigated the utility of video blogs in improving EFL students' performance in giving oral presentations and, further, examined the students' perceptions toward video blogging. Thirty-six English-major juniors participated in a semester-long video blog project for which they uploaded their 3-min. virtual presentation clips over 18 weeks. Their virtual presentation clips were rated by three raters using a scale for speaking performance that contained 14 presentation skills. Data sources included presentation clips, reflections, and interviews. The results indicated that the students' overall presentation performance improved significantly. In particular, among the 14 presentation skills projection, intonation, posture, introduction, conclusion, and purpose saw the most substantial improvement. Finally, the qualitative data revealed that learners perceived that the video blog project facilitated learning but increased anxiety.

  1. Playing prosocial video games increases empathy and decreases schadenfreude.

    Science.gov (United States)

    Greitemeyer, Tobias; Osswald, Silvia; Brauer, Markus

    2010-12-01

    Past research provided abundant evidence that exposure to violent video games increases aggressive tendencies and decreases prosocial tendencies. In contrast, research on the effects of exposure to prosocial video games has been relatively sparse. The present research found support for the hypothesis that exposure to prosocial video games is positively related to prosocial affect and negatively related to antisocial affect. More specifically, two studies revealed that playing a prosocial (relative to a neutral) video game increased interpersonal empathy and decreased reported pleasure at another's misfortune (i.e., schadenfreude). These results lend further credence to the predictive validity of the General Learning Model (Buckley & Anderson, 2006) for the effects of media exposure on social tendencies.

  2. Electrochemical force microscopy

    Science.gov (United States)

    Kalinin, Sergei V.; Jesse, Stephen; Collins, Liam F.; Rodriguez, Brian J.

    2017-01-10

    A system and method for electrochemical force microscopy are provided. The system and method are based on a multidimensional detection scheme that is sensitive to forces experienced by a biased electrode in a solution. The multidimensional approach allows separation of fast processes, such as double layer charging, and charge relaxation, and slow processes, such as diffusion and faradaic reactions, as well as capturing the bias dependence of the response. The time-resolved and bias measurements can also allow probing both linear (small bias range) and non-linear (large bias range) electrochemical regimes and potentially the de-convolution of charge dynamics and diffusion processes from steric effects and electrochemical reactivity.

  3. Reinventing Pocket Microscopy

    CERN Document Server

    Kamal, T; Lee, W M

    2015-01-01

    The key to the success of pocket microscopes stems from the convenience for anyone to magnify the fine details (tens of micrometres) of any object on-thespot. The capability with a portable microscope lets us surpass our limited vision and is commonly used in many areas of science, industry, education. The growth of imaging and computing power in smartphones is creating the possibility of converting your smartphone into a high power pocket microscope. In this article, we briefly describe the history of pocket microscopy and elucidate how mobile technologies are set to become the next platform for pocket microscopes

  4. Hierarchical video surveillance architecture: a chassis for video big data analytics and exploration

    Science.gov (United States)

    Ajiboye, Sola O.; Birch, Philip; Chatwin, Christopher; Young, Rupert

    2015-03-01

    There is increasing reliance on video surveillance systems for systematic derivation, analysis and interpretation of the data needed for predicting, planning, evaluating and implementing public safety. This is evident from the massive number of surveillance cameras deployed across public locations. For example, in July 2013, the British Security Industry Association (BSIA) reported that over 4 million CCTV cameras had been installed in Britain alone. The BSIA also reveal that only 1.5% of these are state owned. In this paper, we propose a framework that allows access to data from privately owned cameras, with the aim of increasing the efficiency and accuracy of public safety planning, security activities, and decision support systems that are based on video integrated surveillance systems. The accuracy of results obtained from government-owned public safety infrastructure would improve greatly if privately owned surveillance systems `expose' relevant video-generated metadata events, such as triggered alerts and also permit query of a metadata repository. Subsequently, a police officer, for example, with an appropriate level of system permission can query unified video systems across a large geographical area such as a city or a country to predict the location of an interesting entity, such as a pedestrian or a vehicle. This becomes possible with our proposed novel hierarchical architecture, the Fused Video Surveillance Architecture (FVSA). At the high level, FVSA comprises of a hardware framework that is supported by a multi-layer abstraction software interface. It presents video surveillance systems as an adapted computational grid of intelligent services, which is integration-enabled to communicate with other compatible systems in the Internet of Things (IoT).

  5. Austin Community College Video Game Development Certificate

    Science.gov (United States)

    McGoldrick, Robert

    2008-01-01

    The Video Game Development program is designed and developed by leaders in the Austin video game development industry, under the direction of the ACC Video Game Advisory Board. Courses are taught by industry video game developers for those who want to become video game developers. The program offers a comprehensive approach towards learning what's…

  6. Heroes and Zeroes: Predicting the Impact of New Video Games on Twitch.tv

    OpenAIRE

    Jones, Isaac; Liu, Huan

    2017-01-01

    Video games and the playing thereof have been a fixture of American culture since their introduction in the arcades of the 1980s. However, it was not until the recent proliferation of broadband connections robust and fast enough to handle live video streaming that players of video games have transitioned from a content consumer role to a content producer role. Simultaneously, the rise of social media has revealed how interpersonal connections drive user engagement and interest. In this work, ...

  7. The Racing-Game Effect: Why Do Video Racing Games Increase Risk-Taking Inclinations?

    OpenAIRE

    Fischer, Peter; Greitemeyer, Tobias; Morton, Thomas; Kastenmüller, Andreas; Postmes, Tom; Frey, Dieter; Kubitzki, Jörg; Odenwälder, Jörg

    2009-01-01

    The present studies investigated why video racing games increase players’ risk-taking inclinations. Four studies reveal that playing video racing games increases risk taking in a subsequent simulated road traffic situation, as well as risk-promoting cognitions and emotions, blood pressure,sensation seeking, and attitudes toward reckless driving. Study 1 ruled out the role of experimental demand in creating such effects. Studies 2 and 3 showed that the effect of playing video racing games on r...

  8. SnapVideo: Personalized Video Generation for a Sightseeing Trip.

    Science.gov (United States)

    Zhang, Luming; Jing, Peiguang; Su, Yuting; Zhang, Chao; Shaoz, Ling

    2017-11-01

    Leisure tourism is an indispensable activity in urban people's life. Due to the popularity of intelligent mobile devices, a large number of photos and videos are recorded during a trip. Therefore, the ability to vividly and interestingly display these media data is a useful technique. In this paper, we propose SnapVideo, a new method that intelligently converts a personal album describing of a trip into a comprehensive, aesthetically pleasing, and coherent video clip. The proposed framework contains three main components. The scenic spot identification model first personalizes the video clips based on multiple prespecified audience classes. We then search for some auxiliary related videos from YouTube 1 according to the selected photos. To comprehensively describe a scenery, the view generation module clusters the crawled video frames into a number of views. Finally, a probabilistic model is developed to fit the frames from multiple views into an aesthetically pleasing and coherent video clip, which optimally captures the semantics of a sightseeing trip. Extensive user studies demonstrated the competitiveness of our method from an aesthetic point of view. Moreover, quantitative analysis reflects that semantically important spots are well preserved in the final video clip. 1 https://www.youtube.com/.

  9. Studenterproduceret video til eksamen

    Directory of Open Access Journals (Sweden)

    Kenneth Hansen

    2016-05-01

    Full Text Available Formålet med denne artikel er at vise, hvordan læringsdesign og stilladsering kan anvendes til at skabe en ramme for studenterproduceret video til eksamen på videregående uddannelser. Artiklen tager udgangspunkt i en problemstilling, hvor uddannelsesinstitutionerne skal håndtere og koordinere undervisning inden for både det faglige område og mediefagligt område og sikre en balance mellem en fagfaglighed og en mediefaglig tilgang. Ved at dele opgaven ud på flere faglige resurser, er der mere koordinering, men man kommer omkring problemet med krav til underviserne om dobbelt faglighed ved medieproduktioner. Med afsæt i Lanarca Declarationens perspektiver på læringsdesign og hovedsageligt Jerome Bruners principper for stilladsering, sammensættes en model for understøttelse af videoproduktion af studerende på videregående uddannelser. Ved at anvende denne model for undervisningssessioner og forløb får de fagfaglige og mediefaglige undervisere et redskab til at fokusere og koordinere indsatsen frem mod målet med, at de studerende producerer og anvender video til eksamen.

  10. Correlative Stochastic Optical Reconstruction Microscopy and Electron Microscopy

    Science.gov (United States)

    Kim, Doory; Deerinck, Thomas J.; Sigal, Yaron M.; Babcock, Hazen P.; Ellisman, Mark H.; Zhuang, Xiaowei

    2015-01-01

    Correlative fluorescence light microscopy and electron microscopy allows the imaging of spatial distributions of specific biomolecules in the context of cellular ultrastructure. Recent development of super-resolution fluorescence microscopy allows the location of molecules to be determined with nanometer-scale spatial resolution. However, correlative super-resolution fluorescence microscopy and electron microscopy (EM) still remains challenging because the optimal specimen preparation and imaging conditions for super-resolution fluorescence microscopy and EM are often not compatible. Here, we have developed several experiment protocols for correlative stochastic optical reconstruction microscopy (STORM) and EM methods, both for un-embedded samples by applying EM-specific sample preparations after STORM imaging and for embedded and sectioned samples by optimizing the fluorescence under EM fixation, staining and embedding conditions. We demonstrated these methods using a variety of cellular targets. PMID:25874453

  11. Magnetic force microscopy

    Science.gov (United States)

    Passeri, Daniele; Dong, Chunhua; Reggente, Melania; Angeloni, Livia; Barteri, Mario; Scaramuzzo, Francesca A; De Angelis, Francesca; Marinelli, Fiorenzo; Antonelli, Flavia; Rinaldi, Federica; Marianecci, Carlotta; Carafa, Maria; Sorbo, Angela; Sordi, Daniela; Arends, Isabel WCE; Rossi, Marco

    2014-01-01

    Magnetic force microscopy (MFM) is an atomic force microscopy (AFM) based technique in which an AFM tip with a magnetic coating is used to probe local magnetic fields with the typical AFM spatial resolution, thus allowing one to acquire images reflecting the local magnetic properties of the samples at the nanoscale. Being a well established tool for the characterization of magnetic recording media, superconductors and magnetic nanomaterials, MFM is finding constantly increasing application in the study of magnetic properties of materials and systems of biological and biomedical interest. After reviewing these latter applications, three case studies are presented in which MFM is used to characterize: (i) magnetoferritin synthesized using apoferritin as molecular reactor; (ii) magnetic nanoparticles loaded niosomes to be used as nanocarriers for drug delivery; (iii) leukemic cells labeled using folic acid-coated core-shell superparamagnetic nanoparticles in order to exploit the presence of folate receptors on the cell membrane surface. In these examples, MFM data are quantitatively analyzed evidencing the limits of the simple analytical models currently used. Provided that suitable models are used to simulate the MFM response, MFM can be used to evaluate the magnetic momentum of the core of magnetoferritin, the iron entrapment efficiency in single vesicles, or the uptake of magnetic nanoparticles into cells. PMID:25050758

  12. Digital holographic microscopy

    Science.gov (United States)

    Barkley, Solomon; Dimiduk, Thomas; Manoharan, Vinothan

    Digital holographic microscopy is a 3D optical imaging technique with high temporal ( ms) and spatial ( 10 nm) precision. However, its adoption as a characterization technique has been limited due to the inherent difficulty of recovering 3D data from the holograms. Successful analysis has traditionally required substantial knowledge about the sample being imaged (for example, the approximate positions of particles in the field of view), as well as expertise in scattering theory. To overcome the obstacles to widespread adoption of holographic microscopy, we developed HoloPy - an open source python package for analysis of holograms and scattering data. HoloPy uses Bayesian statistical methods to determine the geometry and properties of discrete scatterers from raw holograms. We demonstrate the use of HoloPy to measure the dynamics of colloidal particles at interfaces, to ascertain the structures of self-assembled colloidal particles, and to track freely swimming bacteria. The HoloPy codebase is thoroughly tested and well-documented to facilitate use by the broader experimental community. This research is supported by NSF Grant DMR-1306410 and NSERC.

  13. Comparative analysis of video processing and 3D rendering for cloud video games using different virtualization technologies

    Science.gov (United States)

    Bada, Adedayo; Alcaraz-Calero, Jose M.; Wang, Qi; Grecos, Christos

    2014-05-01

    This paper describes a comprehensive empirical performance evaluation of 3D video processing employing the physical/virtual architecture implemented in a cloud environment. Different virtualization technologies, virtual video cards and various 3D benchmarks tools have been utilized in order to analyse the optimal performance in the context of 3D online gaming applications. This study highlights 3D video rendering performance under each type of hypervisors, and other factors including network I/O, disk I/O and memory usage. Comparisons of these factors under well-known virtual display technologies such as VNC, Spice and Virtual 3D adaptors reveal the strengths and weaknesses of the various hypervisors with respect to 3D video rendering and streaming.

  14. Video consultation use by Australian general practitioners: video vignette study.

    Science.gov (United States)

    Jiwa, Moyez; Meng, Xingqiong

    2013-06-19

    There is unequal access to health care in Australia, particularly for the one-third of the population living in remote and rural areas. Video consultations delivered via the Internet present an opportunity to provide medical services to those who are underserviced, but this is not currently routine practice in Australia. There are advantages and shortcomings to using video consultations for diagnosis, and general practitioners (GPs) have varying opinions regarding their efficacy. The aim of this Internet-based study was to explore the attitudes of Australian GPs toward video consultation by using a range of patient scenarios presenting different clinical problems. Overall, 102 GPs were invited to view 6 video vignettes featuring patients presenting with acute and chronic illnesses. For each vignette, they were asked to offer a differential diagnosis and to complete a survey based on the theory of planned behavior documenting their views on the value of a video consultation. A total of 47 GPs participated in the study. The participants were younger than Australian GPs based on national data, and more likely to be working in a larger practice. Most participants (72%-100%) agreed on the differential diagnosis in all video scenarios. Approximately one-third of the study participants were positive about video consultations, one-third were ambivalent, and one-third were against them. In all, 91% opposed conducting a video consultation for the patient with symptoms of an acute myocardial infarction. Inability to examine the patient was most frequently cited as the reason for not conducting a video consultation. Australian GPs who were favorably inclined toward video consultations were more likely to work in larger practices, and were more established GPs, especially in rural areas. The survey results also suggest that the deployment of video technology will need to focus on follow-up consultations. Patients with minor self-limiting illnesses and those with medical

  15. An analysis of lecture video utilization in undergraduate medical education: associations with performance in the courses

    Directory of Open Access Journals (Sweden)

    Chandrasekhar Arcot

    2009-01-01

    Full Text Available Abstract Background Increasing numbers of medical schools are providing videos of lectures to their students. This study sought to analyze utilization of lecture videos by medical students in their basic science courses and to determine if student utilization was associated with performance on exams. Methods Streaming videos of lectures (n = 149 to first year and second year medical students (n = 284 were made available through a password-protected server. Server logs were analyzed over a 10-week period for both classes. For each lecture, the logs recorded time and location from which students accessed the file. A survey was administered at the end of the courses to obtain additional information about student use of the videos. Results There was a wide disparity in the level of use of lecture videos by medical students with the majority of students accessing the lecture videos sparingly (60% of the students viewed less than 10% of the available videos. The anonymous student survey revealed that students tended to view the videos by themselves from home during weekends and prior to exams. Students who accessed lecture videos more frequently had significantly (p Conclusion We conclude that videos of lectures are used by relatively few medical students and that individual use of videos is associated with the degree to which students are having difficulty with the subject matter.

  16. Advanced microscopy of microbial cells

    DEFF Research Database (Denmark)

    Haagensen, Janus Anders Juul; Regenberg, Birgitte; Sternberg, Claus

    2011-01-01

    Growing awareness of heterogeneity in cells of microbial populations has emphasized the importance of advanced microscopy for visualization and understanding of the molecular mechanisms underlying cell-to-cell variation. In this review, we highlight some of the recent advances in confocal...... microscopy, super-resolution optical microscopy (STED, SIM, PALM) as well as atomic force microscopy and Raman spectroscopy. Using examples of bistability in microbial populations as well as biofilm development and differentiation in bacterial and yeast consortia, we demonstrate the importance of microscopy...

  17. Instructional Effectiveness of Video Media.

    Science.gov (United States)

    Wetzel, C. Douglas; And Others

    This volume is a blend of media research, cognitive science research, and tradecraft knowledge regarding video production techniques. The research covers: visual learning; verbal-auditory information; news broadcasts; the value of motion and animation in film and video; simulation (including realism and fidelity); the relationship of text and…

  18. Negotiation for Strategic Video Games

    OpenAIRE

    Afiouni, Einar Nour; Øvrelid, Leif Julian

    2013-01-01

    This project aims to examine the possibilities of using game theoretic concepts and multi-agent systems in modern video games with real time demands. We have implemented a multi-issue negotiation system for the strategic video game Civilization IV, evaluating different negotiation techniques with a focus on the use of opponent modeling to improve negotiation results.

  19. Estimation of Web video multiplicity

    Science.gov (United States)

    Cheung, SenChing S.; Zakhor, Avideh

    1999-12-01

    With ever more popularity of video web-publishing, many popular contents are being mirrored, reformatted, modified and republished, resulting in excessive content duplication. While such redundancy provides fault tolerance for continuous availability of information, it could potentially create problems for multimedia search engines in that the search results for a given query might become repetitious, and cluttered with a large number of duplicates. As such, developing techniques for detecting similarity and duplication is important to multimedia search engines. In addition, content providers might be interested in identifying duplicates of their content for legal, contractual or other business related reasons. In this paper, we propose an efficient algorithm called video signature to detect similar video sequences for large databases such as the web. The idea is to first form a 'signature' for each video sequence by selection a small number of its frames that are most similar to a number of randomly chosen seed images. Then the similarity between any tow video sequences can be reliably estimated by comparing their respective signatures. Using this method, we achieve 85 percent recall and precision ratios on a test database of 377 video sequences. As a proof of concept, we have applied our proposed algorithm to a collection of 1800 hours of video corresponding to around 45000 clips from the web. Our results indicate that, on average, every video in our collection from the web has around five similar copies.

  20. Perancangan Video Game Legenda Anglingdarma

    OpenAIRE

    Siswanto, Jefry Yosua; Ardianto, Deny Tri; Srisanto, Erandaru

    2014-01-01

    Video game dapat digunakan untuk membawakan sebuah cerita rakyat dari negeri masing-masing.Bagi negara-negara yang industri game-nya belum maju, hal ini dapat digunakan sebagai solusi untuk memperkenalkan cerita rakyat.Untuk itu video game ini dibuat agar setidaknya dapat membantu mengenalkan kembali cerita rakyat Indonesia.Dibuat dengan teknik ilustrasi untuk mempermudah pengenalan dan memberikan daya tarik sendiri.