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Sample records for depletion sted microscopy

  1. STED microscopy--super-resolution bio-imaging utilizing a stimulated emission depletion.

    Science.gov (United States)

    Otomo, Kohei; Hibi, Terumasa; Kozawa, Yuichi; Nemoto, Tomomi

    2015-08-01

    One of the most popular super-resolution microscopies that breaks the diffraction barrier is stimulated emission depletion (STED) microscopy. As the optical set-up of STED microscopy is based on a laser scanning microscopy (LSM) system, it potentially has several merits of LSM like confocal or two-photon excitation LSM. In this article, we first describe the principles of STED microscopy and then describe the features of our newly developed two-photon excitation STED microscopy. On the basis of our recent results and those of other researchers, we conclude by discussing future research and new technologies in this field.

  2. Stochastic optical reconstruction microscopy (STORM) in comparison with stimulated emission depletion (STED) and other imaging methods.

    Science.gov (United States)

    Tam, Johnny; Merino, David

    2015-11-01

    Stochastic optical reconstruction microscopy (STORM) and stimulated emission depletion (STED) microscopy are two super-resolution optical microscopy approaches that have rapidly gained popularity in recent years. Both modalities offer super-resolution imaging capabilities with the potential for imaging in multiple colors, three-dimensions, and the possibility to image in live cells. In this review, we focus on the specific advantages and disadvantages of each technique in the context of each other. STORM has been reported to achieve higher spatial resolution when compared to STED, but a lengthy acquisition may be required. STED utilizes relatively higher laser intensities, but is able to generate a super-resolution image immediately after acquisition without the need for any additional data processing. Ultimately, the choice between STORM and STED will depend not only on the specific application, but also on the users' ability to understand and optimize the various parameters ranging from sample preparation to image acquisition, which determine the quality of the final image. Stochastic optical reconstruction microscopy (STORM) and stimulated emission depletion (STED) are two super-resolution microscopy approaches that have rapidly gained popularity in recent years. STORM is based on the precise localization of a large number of individual molecules that together form a super-resolved image (bottom), whereas STED is based on the scanning of two super-imposed light sources which together allow for a super-resolved spot on the sample to be imaged (top). We discuss the specific advantages and disadvantages of each technique and explain the various parameters that affect image quality, which should be taken into consideration when planning experiments.

  3. Reducing Photobleaching in STED Microscopy with Higher Scanning Speed

    CERN Document Server

    Wu, Yong

    2014-01-01

    Photobleaching is a major limitation of super-resolution STED microscopy. We show that the photobleaching rate in STED microscopy is slowed down by scanning with a higher linear speed, enabled by the large field of view in our custom-built resonant-scanning STED microscope. The effect of scanning speed on photobleaching is more remarkable at higher levels of depletion laser irradiance. With a depletion irradiance of 0.4 GW/cm$^2$ (time average), we were able to slow down the photobleaching of the Atto 647N dye by 80% with 8-fold faster scanning. Photobleaching is primarily caused by the depletion light acting upon the excited fluorophores. Experimental data qualitatively agree with a theoretical model. Our results encourage further increasing linear scanning speed for photobleaching reduction in STED microscopy.

  4. Gated CW-STED microscopy: a versatile tool for biological nanometer scale investigation.

    Science.gov (United States)

    Vicidomini, Giuseppe; Hernández, Ivan Coto; d'Amora, Marta; Zanacchi, Francesca Cella; Bianchini, Paolo; Diaspro, Alberto

    2014-03-15

    Stimulation emission depletion (STED) microscopy breaks the spatial resolution limit of conventional light microscopy while retaining its major advantages, such as working under physiological conditions. These properties make STED microscopy a perfect tool for investigating dynamic sub-cellular processes in living organisms. However, up to now, the massive dissemination of STED microscopy has been hindered by the complexity and cost of its implementation. Gated CW-STED (gCW-STED) substantially helps solve this problem without sacrificing spatial resolution. Here, we describe a versatile gCW-STED microscope able to speedily image the specimen, at a resolution below 50 nm, with light intensities comparable to the more complicated all-pulsed STED system. We show this ability on calibration samples as well as on biological samples. Copyright © 2013 Elsevier Inc. All rights reserved.

  5. Super-resolution deep imaging with hollow Bessel beam STED microscopy

    CERN Document Server

    Yu, Wentao; Dong, Dashan; Yang, Xusan; Xiao, Yunfeng; Gong, Qihuang; Xi, Peng; Shi, Kebin

    2015-01-01

    Stimulated emission depletion (STED) microscopy has become a powerful imaging and localized excitation method beating the diffraction barrier for improved lateral spatial resolution in cellular imaging, lithography, etc. Due to specimen-induced aberrations and scattering distortion, it has been a great challenge for STED to maintain consistent lateral resolution deeply inside the specimens. Here we report on a deep imaging STED microscopy by using Gaussian beam for excitation and hollow Bessel beam for depletion (GB-STED). The proposed scheme shows the improved imaging depth up to ~155{\\mu}m in solid agarose sample, ~115{\\mu}m in PDMS and ~100{\\mu}m in phantom of gray matter in brain tissue with consistent super resolution, while the standard STED microscopy shown a significantly reduced lateral resolution at the same imaging depth. The results indicate the excellent imaging penetration capability of GB-STED, making it a promising tool for deep 3D imaging optical nanoscopy and laser fabrication.

  6. STED super-resolution microscopy in Drosophila tissue and in mammalian cells

    Science.gov (United States)

    Lau, Lana; Lee, Yin Loon; Matis, Maja; Axelrod, Jeff; Stearns, Tim; Moerner, W. E.

    2011-03-01

    Far-field super-resolution microscopy is a rapidly emerging method that is opening up opportunities for biological imaging beyond the optical diffraction limit. We have implemented a Stimulated Emission Depletion (STED) microscope to image single dye, cell, and tissue samples with 50-80 nm resolution. First, we compare the STED performance imaging single molecules of several common dyes and report a novel STED dye. Then we apply STED to image planar cell polarity protein complexes in intact fixed Drosophila tissue for the first time. Finally, we present a preliminary study of the centrosomal protein Cep164 in mammalian cells. Our images suggest that Cep164 is arranged in a nine-fold symmetric pattern around the centriole, consistent with findings suggested by cryoelectron tomography. Our work demonstrates that STED microscopy can be used for superresolution imaging in intact tissue and provides ultrastructural information in biological samples as an alternative to immuno-electron microscopy.

  7. Plasmonic nanoprobes for stimulated emission depletion microscopy

    CERN Document Server

    Cortes, Emiliano; Sinclair, Hugo G; Guldbrand, Stina; Peveler, William J; Davies, Timothy; Parrinello, Simona; Görlitz, Frederik; Dunsby, Chris; Neil, Mark A A; Sivan, Yonatan; Parkin, Ivan P; French, Paul M; Maier, Stefan A

    2016-01-01

    Plasmonic nanoparticles influence the absorption and emission processes of nearby emitters due to local enhancements of the illuminating radiation and the photonic density of states. Here, we use the plasmon resonance of metal nanoparticles in order to enhance the stimulated depletion of excited molecules for super-resolved microscopy. We demonstrate stimulated emission depletion (STED) microscopy with gold nanorods with a long axis of only 26 nm and a width of 8 nm that provide an enhancement of the resolution compared to fluorescent-only probes without plasmonic components irradiated with the same depletion power. These novel nanoparticle-assisted STED probes represent a ~2x10^3 reduction in probe volume compared to previously used nanoparticles and we demonstrate their application to the first plasmon-assisted STED cellular imaging. We also discuss their current limitations.

  8. A new filtering technique for removing anti-Stokes emission background in gated CW-STED microscopy.

    Science.gov (United States)

    Coto Hernàndez, Ivàn; Peres, Chiara; Cella Zanacchi, Francesca; d'Amora, Marta; Christodoulou, Sotirios; Bianchini, Paolo; Diaspro, Alberto; Vicidomini, Giuseppe

    2014-06-01

    Stimulated emission depletion (STED) microscopy is a prominent approach of super-resolution optical microscopy, which allows cellular imaging with so far unprecedented unlimited spatial resolution. The introduction of time-gated detection in STED microscopy significantly reduces the (instantaneous) intensity required to obtain sub-diffraction spatial resolution. If the time-gating is combined with a STED beam operating in continuous wave (CW), a cheap and low labour demand implementation is obtained, the so called gated CW-STED microscope. However, time-gating also reduces the fluorescence signal which forms the image. Thereby, background sources such as fluorescence emission excited by the STED laser (anti-Stokes fluorescence) can reduce the effective resolution of the system. We propose a straightforward method for subtraction of anti-Stokes background. The method hinges on the uncorrelated nature of the anti-Stokes emission background with respect to the wanted fluorescence signal. The specific importance of the method towards the combination of two-photon-excitation with gated CW-STED microscopy is demonstrated. Copyright © 2014 The Authors. J. Biophotonics published by Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim • This is an open access article under the terms of the Creative Commons Attribution-License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

  9. STED microscopy of living cells--new frontiers in membrane and neurobiology.

    Science.gov (United States)

    Eggeling, Christian; Willig, Katrin I; Barrantes, Francisco J

    2013-07-01

    Recent developments in fluorescence far-field microscopy such as STED microscopy have accomplished observation of the living cell with a spatial resolution far below the diffraction limit. Here, we briefly review the current approaches to super-resolution optical microscopy and present the implementation of STED microscopy for novel insights into live cell mechanisms, with a focus on neurobiology and plasma membrane dynamics.

  10. Fluorescent Rhodamines and Fluorogenic Carbopyronines for Super-Resolution STED Microscopy in Living Cells.

    Science.gov (United States)

    Butkevich, Alexey N; Mitronova, Gyuzel Yu; Sidenstein, Sven C; Klocke, Jessica L; Kamin, Dirk; Meineke, Dirk N H; D'Este, Elisa; Kraemer, Philip-Tobias; Danzl, Johann G; Belov, Vladimir N; Hell, Stefan W

    2016-03-01

    A range of bright and photostable rhodamines and carbopyronines with absorption maxima in the range of λ=500-630 nm were prepared, and enabled the specific labeling of cytoskeletal filaments using HaloTag technology followed by staining with 1 μm solutions of the dye-ligand conjugates. The synthesis, photophysical parameters, fluorogenic behavior, and structure-property relationships of the new dyes are discussed. Light microscopy with stimulated emission depletion (STED) provided one- and two-color images of living cells with an optical resolution of 40-60 nm.

  11. STED super-resolution microscopy reveals an array of MINOS clusters along human mitochondria.

    Science.gov (United States)

    Jans, Daniel C; Wurm, Christian A; Riedel, Dietmar; Wenzel, Dirk; Stagge, Franziska; Deckers, Markus; Rehling, Peter; Jakobs, Stefan

    2013-05-28

    The mitochondrial inner membrane organizing system (MINOS) is a conserved large hetero-oligomeric protein complex in the mitochondrial inner membrane, crucial for the maintenance of cristae morphology. MINOS has been suggested to represent the core of an extended protein network that controls mitochondrial function and structure, and has been linked to several human diseases. The spatial arrangement of MINOS within mitochondria is ill-defined, however. Using super-resolution stimulated emission depletion (STED) microscopy and immunogold electron microscopy, we determined the distribution of three known human MINOS subunits (mitofilin, MINOS1, and CHCHD3) in mammalian cells. Super-resolution microscopy revealed that all three subunits form similar clusters within mitochondria, and that MINOS is more abundant in mitochondria around the nucleus than in peripheral mitochondria. At the submitochondrial level, mitofilin, a core MINOS subunit, is preferentially localized at cristae junctions. In primary human fibroblasts, mitofilin labeling uncovered a regularly spaced pattern of clusters arranged in parallel to the cell growth surfaces. We suggest that this array of MINOS complexes might explain the observed phenomenon of largely horizontally arranged cristae junctions that connect the inner boundary membrane to lamellar cristae. The super-resolution images demonstrate an unexpectedly high level of regularity in the nanoscale distribution of the MINOS complex in human mitochondria, supporting an integrating role of MINOS in the structural organization of the organelle.

  12. STED super-resolution microscopy of clinical paraffin-embedded human rectal cancer tissue.

    Science.gov (United States)

    Ilgen, Peter; Stoldt, Stefan; Conradi, Lena-Christin; Wurm, Christian Andreas; Rüschoff, Josef; Ghadimi, B Michael; Liersch, Torsten; Jakobs, Stefan

    2014-01-01

    Formalin fixed and paraffin-embedded human tissue resected during cancer surgery is indispensable for diagnostic and therapeutic purposes and represents a vast and largely unexploited resource for research. Optical microscopy of such specimen is curtailed by the diffraction-limited resolution of conventional optical microscopy. To overcome this limitation, we used STED super-resolution microscopy enabling optical resolution well below the diffraction barrier. We visualized nanoscale protein distributions in sections of well-annotated paraffin-embedded human rectal cancer tissue stored in a clinical repository. Using antisera against several mitochondrial proteins, STED microscopy revealed distinct sub-mitochondrial protein distributions, suggesting a high level of structural preservation. Analysis of human tissues stored for up to 17 years demonstrated that these samples were still amenable for super-resolution microscopy. STED microscopy of sections of HER2 positive rectal adenocarcinoma revealed details in the surface and intracellular HER2 distribution that were blurred in the corresponding conventional images, demonstrating the potential of super-resolution microscopy to explore the thus far largely untapped nanoscale regime in tissues stored in biorepositories.

  13. STED super-resolution microscopy of clinical paraffin-embedded human rectal cancer tissue.

    Directory of Open Access Journals (Sweden)

    Peter Ilgen

    Full Text Available Formalin fixed and paraffin-embedded human tissue resected during cancer surgery is indispensable for diagnostic and therapeutic purposes and represents a vast and largely unexploited resource for research. Optical microscopy of such specimen is curtailed by the diffraction-limited resolution of conventional optical microscopy. To overcome this limitation, we used STED super-resolution microscopy enabling optical resolution well below the diffraction barrier. We visualized nanoscale protein distributions in sections of well-annotated paraffin-embedded human rectal cancer tissue stored in a clinical repository. Using antisera against several mitochondrial proteins, STED microscopy revealed distinct sub-mitochondrial protein distributions, suggesting a high level of structural preservation. Analysis of human tissues stored for up to 17 years demonstrated that these samples were still amenable for super-resolution microscopy. STED microscopy of sections of HER2 positive rectal adenocarcinoma revealed details in the surface and intracellular HER2 distribution that were blurred in the corresponding conventional images, demonstrating the potential of super-resolution microscopy to explore the thus far largely untapped nanoscale regime in tissues stored in biorepositories.

  14. Two-Photon Excitation STED Microscopy with Time-Gated Detection.

    Science.gov (United States)

    Coto Hernández, Iván; Castello, Marco; Lanzanò, Luca; d'Amora, Marta; Bianchini, Paolo; Diaspro, Alberto; Vicidomini, Giuseppe

    2016-01-13

    We report on a novel two-photon excitation stimulated emission depletion (2PE-STED) microscope based on time-gated detection. The time-gated detection allows for the effective silencing of the fluorophores using moderate stimulated emission beam intensity. This opens the possibility of implementing an efficient 2PE-STED microscope with a stimulated emission beam running in a continuous-wave. The continuous-wave stimulated emission beam tempers the laser architecture's complexity and cost, but the time-gated detection degrades the signal-to-noise ratio (SNR) and signal-to-background ratio (SBR) of the image. We recover the SNR and the SBR through a multi-image deconvolution algorithm. Indeed, the algorithm simultaneously reassigns early-photons (normally discarded by the time-gated detection) to their original positions and removes the background induced by the stimulated emission beam. We exemplify the benefits of this implementation by imaging sub-cellular structures. Finally, we discuss of the extension of this algorithm to future all-pulsed 2PE-STED implementationd based on time-gated detection and a nanosecond laser source.

  15. ns-time resolution for multispecies STED-FLIM and artifact free STED-FCS

    Science.gov (United States)

    Koenig, Marcelle; Reisch, Paja; Dowler, Rhys; Kraemer, Benedikt; Tannert, Sebastian; Patting, Matthias; Clausen, Mathias P.; Galiani, Silvia; Eggeling, Christian; Koberling, Felix; Erdmann, Rainer

    2016-03-01

    Stimulated Emission Depletion (STED) Microscopy has evolved into a well established method offering optical superresolution below 50 nm. Running both excitation and depletion lasers in picosecond pulsed modes allows for highest optical resolution as well as fully exploiting the photon arrival time information using time-resolved single photon counting (TCSPC). Non-superresolved contributions can be easily dismissed through time-gated detection (gated STED) or a more detailed fluorescence decay analysis (FLIM-STED), both leading to an even further improved imaging resolution. Furthermore, these methods allow for accurate separation of different fluorescent species, especially if subtle differences in the excitation and emission spectra as well as the fluorescence decay are taken into account in parallel. STED can also be used to shrink the observation volume while studying the dynamics of diffusing species in Fluorescence Correlation Spectroscopy (FCS) to overcome averaging issues along long transit paths. A further unique advantage of STED-FCS is that the observation spot diameter can be tuned in a gradual manner enabling, for example, determining the type of hindered diffusion in lipid membrane studies. Our completely pulsed illumination scheme allows realizing an improved STED-FCS data acquisition using pulsed interleaved excitation (PIE). PIE-STED-FCS allows for a straightforward online check whether the STED laser has an influence on the investigated diffusion dynamics.

  16. Massive Parallelization of STED Nanoscopy Using Optical Lattices

    CERN Document Server

    Yang, Bin; Mestre, Michael; Trebbia, Jean-Baptiste; Lounis, Brahim

    2013-01-01

    Recent developments in stimulated emission depletion (STED) microscopy achieved nanometer scale resolution and showed great potential in live cell imaging. Yet, STED nanoscopy techniques are based on single point-scanning. This constitutes a drawback for wide field imaging, since the gain in spatial resolution requires dense pixelation and hence long recording times. Here we achieve massive parallelization of STED nanoscopy using wide-field excitation together with well-designed optical lattices for depletion and a fast camera for detection. Acquisition of large field of view super-resolved images requires scanning over a single unit cell of the optical lattice which can be as small as 290 nm*290nm. Interference STED (In-STED) images of 2.9 {\\mu}m* 2.9 {\\mu}m with resolution down to 70 nm are obtained at 12.5 frames per second. The development of this technique opens many prospects for fast wide-field nanoscopy.

  17. 基于时间相关单光子计数的离线式g-STED超分辨显微术%Super Resolution Microscopy of Offline g-STED Microscopy Based on Time-Correlated Single Photon Counting

    Institute of Scientific and Technical Information of China (English)

    郝翔; 匡翠方; 顾兆泰; 李帅; 刘旭

    2013-01-01

    提出了一种离线式基于时间门的荧光受激发射损耗(g-STED)显微方法.基于在强光照条件下荧光寿命缩短的理论模型,在常规STED架构基础上,使用时间相关单光子记数(TCSPC)算法获取图像的荧光寿命信息,离线设置合理的时间门阈值,丢弃短寿命信号数据,对荧光信号有效点扩展函数(PSF)进行压缩,达到超分辨显微的目的.与传统STED显微术相比,此方法所需光功率大幅度降低,减少了荧光漂白及光毒性;离线式处理则同时增加了时间门设置的灵活性.在实验中,使用45 rnW的连续STED光,最终获取了约80 nm的图像空间分辨率.进一步对时间门的设置对获取图像信号的分辨率和信噪比的影响进行了讨论.%The offline time-gated stimulated emission depletion (g-STED) microscopy, which is based on time-correlated single photon counting (TCSPC) algorithm, is proposed. As STED beam can eliminate the ratio of spontaneous fluorescent emission while reducing the fluorescence lifetime, the lifetime of fluorescent signals in the center of excitation focal spot and that in the surrounding doughnut area which are overlap by the STED focal spot are significant different. Based on this principle, in a general continuous wave STED (CW-STED), the fluorescent lifetimes of the whole imaging region are calculated by TCSPC, and the signals with shorter lifetime are discarded after all data recorded. The effective point spread function (PSF) of each fluorescent labels are shrinked in order to enhance the resolution. Compared with traditional ones, this offline g-STED not only decreases the incident intensity of laser to avoid the risk of fluorescence photobleaching and optical toxicity, but also increases the flexibility of time-gate manipulation. A spatial resolution of 80 nm is obtained in the experiment when only 45 mW STED beam is introduced. The potential influences of time-gate selection to the resolution and signal-to-noise ratio

  18. Phase filter enhanced STED-4Pi fluorescence microscopy: theory and experiment

    Energy Technology Data Exchange (ETDEWEB)

    Dyba, M; Keller, J; Hell, S W [Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, D-37070 Goettingen (Germany)

    2005-05-01

    We study the point-spread and optical transfer-function (OTF) of a stimulated emission depletion (STED)-4Pi fluorescence microscope that provides diffraction unlimited resolution along the optic axis. Our calculations take into account the orientation of the linear transition dipole moment of the fluorescent molecules with respect to that of the focal field. We demonstrate a subdiffraction axial resolution of 44-48 nm for water-immersion lenses, corresponding to a 7-8-fold expansion of the OTF beyond the diffraction barrier of a single lens confocal microscope, which is in excellent agreement with theoretical predictions for the conditions applied. Furthermore, we study phase modifications of the wavefront of the stimulating beam that strengthen weakly transferred frequencies within the OTF support. The enlarged bandwidth enables the separation of objects at 76 nm axial distance.

  19. Hyperspectral stimulated emission depletion microscopy and methods of use thereof

    Science.gov (United States)

    Timlin, Jerilyn A; Aaron, Jesse S

    2014-04-01

    A hyperspectral stimulated emission depletion ("STED") microscope system for high-resolution imaging of samples labeled with multiple fluorophores (e.g., two to ten fluorophores). The hyperspectral STED microscope includes a light source, optical systems configured for generating an excitation light beam and a depletion light beam, optical systems configured for focusing the excitation and depletion light beams on a sample, and systems for collecting and processing data generated by interaction of the excitation and depletion light beams with the sample. Hyperspectral STED data may be analyzed using multivariate curve resolution analysis techniques to deconvolute emission from the multiple fluorophores. The hyperspectral STED microscope described herein can be used for multi-color, subdiffraction imaging of samples (e.g., materials and biological materials) and for analyzing a tissue by Forster Resonance Energy Transfer ("FRET").

  20. Effects of coherence and vector properties of the light on the resolution limit in stimulated emission depletion fluorescence microscopy.

    Science.gov (United States)

    Gao, Wanrong

    2008-06-01

    Stimulated emission depletion (STED) fluorescence microscopy is a diffraction-unlimited microscopy. We report a method of analyzing the intensity distribution in the focal region. The method takes both the coherence and the vector properties of the light into account. By using the Gaussian Schell model to describe the cross-spectral density function of the incident beam, we show that the coherence that exists between the electric field at any two points is one of the factors that limit further increase of the spatial resolution in STED fluorescence microscopy.

  1. ''Et sted''

    DEFF Research Database (Denmark)

    Dinesen, Cort Ross

    2009-01-01

    At arkitekturen er forbundet med og forankret til "et sted" - det at arkitekturen finder sted og at arkitekturen står et sted, - og at arkitekturen sætter en målelighed i det umålelige og skaber permanens er velkendt. Samtidig bevæger vi os fra "sted" til "sted" i værket eller mellem værker og vo...

  2. Multicolour Multilevel STED nanoscopy of Actin/Spectrin Organization at Synapses.

    Science.gov (United States)

    Sidenstein, Sven C; D'Este, Elisa; Böhm, Marvin J; Danzl, Johann G; Belov, Vladimir N; Hell, Stefan W

    2016-05-25

    Superresolution fluorescence microscopy of multiple fluorophores still requires development. Here we present simultaneous three-colour stimulated emission depletion (STED) nanoscopy relying on a single STED beam at 620 nm. Toggling the STED beam between two or more power levels ("multilevelSTED") optimizes resolution and contrast in all colour channels, which are intrinsically co-aligned and well separated. Three-colour recording is demonstrated by imaging the nanoscale cytoskeletal organization in cultured hippocampal neurons. The down to ~35 nm resolution identified periodic actin/betaII spectrin lattices along dendrites and spines; however, at presynaptic and postsynaptic sites, these patterns were found to be absent. Both our multicolour scheme and the 620 nm STED line should be attractive for routine STED microscopy applications.

  3. Achieving λ/10 resolution CW STED nanoscopy with a Ti:Sapphire oscillator.

    Directory of Open Access Journals (Sweden)

    Yujia Liu

    Full Text Available In this report, a Ti:Sapphire oscillator was utilized to realize synchronization-free stimulated emission depletion (STED microscopy. With pump power of 4.6 W and sample irradiance of 310 mW, we achieved super-resolution as high as 71 nm. With synchronization-free STED, we imaged 200 nm nanospheres as well as all three cytoskeletal elements (microtubules, intermediate filaments, and actin filaments, clearly demonstrating the resolving power of synchronization-free STED over conventional diffraction limited imaging. It also allowed us to discover that, Dylight 650, exhibits improved performance over ATTO647N, a fluorophore frequently used in STED. Furthermore, we applied synchronization-free STED to image fluorescently-labeled intracellular viral RNA granules, which otherwise cannot be differentiated by confocal microscopy. Thanks to the widely available Ti:Sapphire oscillators in multiphoton imaging system, this work suggests easier access to setup super-resolution microscope via the synchronization-free STED.

  4. Stimulated emission depletion microscopy resolves individual nitrogen vacancy centers in diamond nanocrystals.

    OpenAIRE

    Arroyo Camejo, S.; Adam, M; Besbes, M.; Hugonin, J.; Jaques, V.; Greffet, J.; Roch, J.; Hell, S.; Treussart, F.

    2013-01-01

    Nitrogen-vacancy (NV) color centers in nanodiamonds are highly promising for bioimaging and sensing. However, resolving individual NV centers within nanodiamond particles and the controlled addressing and readout of their spin state has remained a major challenge. Spatially stochastic super-resolution techniques cannot provide this capability in principle, whereas coordinate-controlled super-resolution imaging methods, like stimulated emission depletion (STED) microscopy, have been predicted ...

  5. A STED-FLIM microscope applied to imaging the natural killer cell immune synapse

    Science.gov (United States)

    Lenz, M. O.; Brown, A. C. N.; Auksorius, E.; Davis, D. M.; Dunsby, C.; Neil, M. A. A.; French, P. M. W.

    2011-03-01

    We present a stimulated emission depletion (STED) fluorescence lifetime imaging (FLIM) microscope, excited by a microstructured optical fibre supercontinuum source that is pumped by a femtosecond Ti:Sapphire-laser, which is also used for depletion. Implemented using a piezo-scanning stage on a laser scanning confocal fluorescence microscope system with FLIM realised using time correlated single photon counting (TCSPC), this provides convenient switching between confocal and STED-FLIM with spatial resolution down to below 60 nm. We will present our design considerations to make a robust instrument for biological applications including a comparison between fixed phase plate and spatial light modulator (SLM) approaches to shape the STED beam and the correlation of STED and confocal FLIM microscopy. Following our previous application of FLIM-FRET to study intercellular signalling at the immunological synapse (IS), we are employing STED microscopy to characterize the spatial distribution of cellular molecules with subdiffraction resolution at the IS. In particular, we are imaging cytoskeletal structure at the Natural Killer cell activated immune synapse. We will also present our progress towards multilabel STED microscopy to determine how relative spatial molecular organization, previously undetectable by conventional microscopy techniques, is important for NK cell cytotoxic function. Keywords: STED, Stimulated Emission Depletion Microscopy, Natural Killer (NK) cell, Fluorescence lifetime imaging, FLIM, Super resolution microscopy.

  6. Nanoparticle-assisted STED nanoscopy with gold nanospheres

    CERN Document Server

    Urban, Nicolai T; Hell, Stefan W; Sivan, Yonatan

    2016-01-01

    We demonstrate stimulated emission depletion (STED) microscopy with 20 nm gold nanospheres coated by fluorescent silica. Compared with previous demonstrations of STED with a hybrid plasmonic fluorescent label, the current implementation offers a substantially smaller label and a better resolution improvement of up to 2.5-fold beyond the diffraction limit of confocal microscopy. This is achieved at approximately 2 times lower intensity than conventional STED based on dyes alone, and in an aqueous environment, demonstrating the relevance to bio-imaging. Finally, we also show, for the first time in this context, a 3-fold reduction in the rate of photobleaching compared to standard dye-based STED, thus, enabling brighter images.

  7. Measuring Exciton Migration in Conjugated Polymer Films with Ultrafast Time Resolved Stimulated Emission Depletion Microscopy

    Science.gov (United States)

    Penwell, Samuel

    Conjugated polymers are highly tunable organic semiconductors, which can be solution processed to form thin films, making them prime candidates for organic photovoltaic devices. One of the most important parameters in a conjugated polymer solar cell is the exciton diffusion length, which depends on intermolecular couplings, and is typically on the order of 10 nm. This mean exciton migration can vary dramatically between films and within a single film due to heterogeneities in morphology on length scales of 10's to 100's nm. To study the variability of exciton diffusion and morphology within individual conjugated polymer films, we are adapting stimulated emission depletion (STED) microscopy. STED is typically used in biology with sparse well-engineered fluorescent labels or on NV-centers in diamond. I will, however, describe how we have demonstrated the extension of STED to conjugated polymer films and nanoparticles of MEH-PPV and CN-PPV, despite the presence of two photon absorption, by taking care to first understand the material's photophysical properties. We then further adapt this approach, by introducing a second ultrafast STED pulse at a variable delay. Excitons that migrate away from the initial subdiffraction excitation volume during the ps-ns time delay, are preferentially quenched by the second STED pulse, while those that remain in the initial volume survive. The resulting effect of the second STED pulse is modulated by the degree of migration over the ultrafast time delay, thus providing a new method to study exciton migration. Since this technique utilizes subdiffraction optical excitation and detection volumes with ultrafast time resolution, it provides a means of spatially and temporally resolving measurements of exciton migration on the native length and time scales. In this way, we will obtain a spatiotemporal map of exciton distributions and migration that will help to correlate the energetic landscape to film morphology at the nanoscale.

  8. Multicolour Multilevel STED nanoscopy of Actin/Spectrin Organization at Synapses

    Science.gov (United States)

    Sidenstein, Sven C.; D'Este, Elisa; Böhm, Marvin J.; Danzl, Johann G.; Belov, Vladimir N.; Hell, Stefan W.

    2016-05-01

    Superresolution fluorescence microscopy of multiple fluorophores still requires development. Here we present simultaneous three-colour stimulated emission depletion (STED) nanoscopy relying on a single STED beam at 620 nm. Toggling the STED beam between two or more power levels (“multilevelSTED”) optimizes resolution and contrast in all colour channels, which are intrinsically co-aligned and well separated. Three-colour recording is demonstrated by imaging the nanoscale cytoskeletal organization in cultured hippocampal neurons. The down to ~35 nm resolution identified periodic actin/betaII spectrin lattices along dendrites and spines; however, at presynaptic and postsynaptic sites, these patterns were found to be absent. Both our multicolour scheme and the 620 nm STED line should be attractive for routine STED microscopy applications.

  9. STED nanoscopy with time-gated detection: theoretical and experimental aspects.

    Directory of Open Access Journals (Sweden)

    Giuseppe Vicidomini

    Full Text Available In a stimulated emission depletion (STED microscope the region in which fluorescence markers can emit spontaneously shrinks with continued STED beam action after a singular excitation event. This fact has been recently used to substantially improve the effective spatial resolution in STED nanoscopy using time-gated detection, pulsed excitation and continuous wave (CW STED beams. We present a theoretical framework and experimental data that characterize the time evolution of the effective point-spread-function of a STED microscope and illustrate the physical basis, the benefits, and the limitations of time-gated detection both for CW and pulsed STED lasers. While gating hardly improves the effective resolution in the all-pulsed modality, in the CW-STED modality gating strongly suppresses low spatial frequencies in the image. Gated CW-STED nanoscopy is in essence limited (only by the reduction of the signal that is associated with gating. Time-gated detection also reduces/suppresses the influence of local variations of the fluorescence lifetime on STED microscopy resolution.

  10. Nearest neighbor analysis of dopamine D1 receptors and Na(+)-K(+)-ATPases in dendritic spines dissected by STED microscopy.

    Science.gov (United States)

    Blom, Hans; Rönnlund, Daniel; Scott, Lena; Spicarova, Zuzana; Rantanen, Ville; Widengren, Jerker; Aperia, Anita; Brismar, Hjalmar

    2012-02-01

    Protein localization in dendritic spines is the focus of intense investigations within neuroscience. Applications of super-resolution microscopy to dissect nanoscale protein distributions, as shown in this work with dual-color STED, generate spatial correlation coefficients having quite small values. This means that colocalization analysis to some extent looses part of its correlative impact. In this study we thus introduced nearest neighbor analysis to quantify the spatial relations between two important proteins in neurons, the dopamine D1 receptor and Na(+),K(+)-ATPase. The analysis gave new information on how dense the D1 receptor and Na(+),K(+)-ATPase constituting nanoclusters are located both with respect to the homogenous (self to same) and the heterogeneous (same to other) topology. The STED dissected nanoscale topologies provide evidence for both a joint as well as a separated confinement of the D1 receptor and the Na(+),K(+)-ATPase in the postsynaptic areas of dendritic spines. This confined topology may have implications for generation of local sodium gradients and for structural and functional interactions modulating slow synaptic transmission processes. Copyright © 2011 Wiley Periodicals, Inc.

  11. "Reduced" Coumarin Dyes with an O-Phosphorylated 2,2-Dimethyl-4-(hydroxymethyl)-1,2,3,4-tetrahydroquinoline Fragment: Synthesis, Spectra, and STED Microscopy.

    Science.gov (United States)

    Nizamov, Shamil; Sednev, Maksim V; Bossi, Mariano L; Hebisch, Elke; Frauendorf, Holm; Lehnart, Stephan E; Belov, Vladimir N; Hell, Stefan W

    2016-08-01

    Large Stokes-shift coumarin dyes with an O-phosphorylated 4-(hydroxymethyl)-2,2-dimethyl-1,2,3,4-tetrahydroquinoline fragment emitting in the blue, green, and red regions of the visible spectrum were synthesized. For this purpose, N-substituted and O-protected 1,2-dihydro-7-hydroxy-2,2,4-trimethylquinoline was oxidized with SeO2 to the corresponding α,β-unsaturated aldehyde and then reduced with NaBH4 in a "one-pot" fashion to yield N-substituted and 7-O-protected 4-(hydroxymethyl)-7-hydroxy-2,2-dimethyl-1,2,3,4-tetrahydroquinoline as a common precursor to all the coumarin dyes reported here. The photophysical properties of the new dyes ("reduced coumarins") and 1,2-dihydroquinoline analogues (formal precursors) with a trisubstituted C=C bond were compared. The "reduced coumarins" were found to be more photoresistant and brighter than their 1,2-dihydroquinoline counterparts. Free carboxylate analogues, as well as their antibody conjugates (obtained from N-hydroxysuccinimidyl esters) were also prepared. All studied conjugates with secondary antibodies afforded high specificity and were suitable for fluorescence microscopy. The red-emitting coumarin dye bearing a betaine fragment at the C-3-position showed excellent performance in stimulation emission depletion (STED) microscopy.

  12. Stimulated emission depletion microscopy resolves individual nitrogen vacancy centers in diamond nanocrystals.

    Science.gov (United States)

    Arroyo-Camejo, Silvia; Adam, Marie-Pierre; Besbes, Mondher; Hugonin, Jean-Paul; Jacques, Vincent; Greffet, Jean-Jacques; Roch, Jean-François; Hell, Stefan W; Treussart, François

    2013-12-23

    Nitrogen-vacancy (NV) color centers in nanodiamonds are highly promising for bioimaging and sensing. However, resolving individual NV centers within nanodiamond particles and the controlled addressing and readout of their spin state has remained a major challenge. Spatially stochastic super-resolution techniques cannot provide this capability in principle, whereas coordinate-controlled super-resolution imaging methods, like stimulated emission depletion (STED) microscopy, have been predicted to fail in nanodiamonds. Here we show that, contrary to these predictions, STED can resolve single NV centers in 40-250 nm sized nanodiamonds with a resolution of ≈10 nm. Even multiple adjacent NVs located in single nanodiamonds can be imaged individually down to relative distances of ≈15 nm. Far-field optical super-resolution of NVs inside nanodiamonds is highly relevant for bioimaging applications of these fluorescent nanolabels. The targeted addressing and readout of individual NV(-) spins inside nanodiamonds by STED should also be of high significance for quantum sensing and information applications.

  13. Ultrahigh-contrast imaging by temporally modulated stimulated emission depletion

    NARCIS (Netherlands)

    Doronina-Amitonova, L.V.; Fedotov, I.V.; Zheltikov, A.M.

    2015-01-01

    Stimulated emission depletion (STED) is the key optical technology enabling super-resolution microscopy below the diffraction limit. Here, we demonstrate that modulation of STED in the time domain, combined with properly designed lock-in detection, can radically enhance the contrast of fluorescent i

  14. Upgrade of a Scanning Confocal Microscope to a Single-Beam Path STED Microscope.

    Directory of Open Access Journals (Sweden)

    André Klauss

    Full Text Available By overcoming the diffraction limit in light microscopy, super-resolution techniques, such as stimulated emission depletion (STED microscopy, are experiencing an increasing impact on life sciences. High costs and technically demanding setups, however, may still hinder a wider distribution of this innovation in biomedical research laboratories. As far-field microscopy is the most widely employed microscopy modality in the life sciences, upgrading already existing systems seems to be an attractive option for achieving diffraction-unlimited fluorescence microscopy in a cost-effective manner. Here, we demonstrate the successful upgrade of a commercial time-resolved confocal fluorescence microscope to an easy-to-align STED microscope in the single-beam path layout, previously proposed as "easy-STED", achieving lateral resolution < λ/10 corresponding to a five-fold improvement over a confocal modality. For this purpose, both the excitation and depletion laser beams pass through a commercially available segmented phase plate that creates the STED-doughnut light distribution in the focal plane, while leaving the excitation beam unaltered when implemented into the joint beam path. Diffraction-unlimited imaging of 20 nm-sized fluorescent beads as reference were achieved with the wavelength combination of 635 nm excitation and 766 nm depletion. To evaluate the STED performance in biological systems, we compared the popular phalloidin-coupled fluorescent dyes Atto647N and Abberior STAR635 by labeling F-actin filaments in vitro as well as through immunofluorescence recordings of microtubules in a complex epithelial tissue. Here, we applied a recently proposed deconvolution approach and showed that images obtained from time-gated pulsed STED microscopy may benefit concerning the signal-to-background ratio, from the joint deconvolution of sub-images with different spatial information which were extracted from offline time gating.

  15. Sub-diffraction nano manipulation using STED AFM.

    Science.gov (United States)

    Chacko, Jenu Varghese; Canale, Claudio; Harke, Benjamin; Diaspro, Alberto

    2013-01-01

    In the last two decades, nano manipulation has been recognized as a potential tool of scientific interest especially in nanotechnology and nano-robotics. Contemporary optical microscopy (super resolution) techniques have also reached the nanometer scale resolution to visualize this and hence a combination of super resolution aided nano manipulation ineluctably gives a new perspective to the scenario. Here we demonstrate how specificity and rapid determination of structures provided by stimulated emission depletion (STED) microscope can aid another microscopic tool with capability of mechanical manoeuvring, like an atomic force microscope (AFM) to get topological information or to target nano scaled materials. We also give proof of principle on how high-resolution real time visualization can improve nano manipulation capability within a dense sample, and how STED-AFM is an optimal combination for this job. With these evidences, this article points to future precise nano dissections and maybe even to a nano-snooker game with an AFM tip and fluorospheres.

  16. 2000-fold parallelized dual-color STED fluorescence nanoscopy.

    Science.gov (United States)

    Bergermann, Fabian; Alber, Lucas; Sahl, Steffen J; Engelhardt, Johann; Hell, Stefan W

    2015-01-12

    Stimulated Emission Depletion (STED) nanoscopy enables multi-color fluorescence imaging at the nanometer scale. Its typical single-point scanning implementation can lead to long acquisition times. In order to unleash the full spatiotemporal resolution potential of STED nanoscopy, parallelized scanning is mandatory. Here we present a dual-color STED nanoscope utilizing two orthogonally crossed standing light waves as a fluorescence switch-off pattern, and providing a resolving power down to 30 nm. We demonstrate the imaging capabilities in a biological context for immunostained vimentin fibers in a circular field of view of 20 µm diameter at 2000-fold parallelization (i.e. 2000 "intensity minima"). The technical feasibility of massively parallelizing STED without significant compromises in resolution heralds video-rate STED nanoscopy of large fields of view, pending the availability of suitable high-speed detectors.

  17. Multi-images deconvolution improves signal-to-noise ratio on gated stimulated emission depletion microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Castello, Marco [Nanobiophotonics, Nanophysics, Istituto Italiano di Tecnologia, Via Morego 30, Genoa, 16163 (Italy); DIBRIS, University of Genoa, Via Opera Pia 13, Genoa 16145 (Italy); Diaspro, Alberto [Nanobiophotonics, Nanophysics, Istituto Italiano di Tecnologia, Via Morego 30, Genoa, 16163 (Italy); Nikon Imaging Center, Via Morego 30, Genoa 16163 (Italy); Vicidomini, Giuseppe, E-mail: giuseppe.vicidomini@iit.it [Nanobiophotonics, Nanophysics, Istituto Italiano di Tecnologia, Via Morego 30, Genoa, 16163 (Italy)

    2014-12-08

    Time-gated detection, namely, only collecting the fluorescence photons after a time-delay from the excitation events, reduces complexity, cost, and illumination intensity of a stimulated emission depletion (STED) microscope. In the gated continuous-wave- (CW-) STED implementation, the spatial resolution improves with increased time-delay, but the signal-to-noise ratio (SNR) reduces. Thus, in sub-optimal conditions, such as a low photon-budget regime, the SNR reduction can cancel-out the expected gain in resolution. Here, we propose a method which does not discard photons, but instead collects all the photons in different time-gates and recombines them through a multi-image deconvolution. Our results, obtained on simulated and experimental data, show that the SNR of the restored image improves relative to the gated image, thereby improving the effective resolution.

  18. Fluorescent dyes with large Stokes shifts for super-resolution optical microscopy of biological objects: a review

    Science.gov (United States)

    Sednev, Maksim V.; Belov, Vladimir N.; Hell, Stefan W.

    2015-12-01

    The review deals with commercially available organic dyes possessing large Stokes shifts and their applications as fluorescent labels in optical microscopy based on stimulated emission depletion (STED). STED microscopy breaks Abbe’s diffraction barrier and provides optical resolution beyond the diffraction limit. STED microscopy is non-invasive and requires photostable fluorescent markers attached to biomolecules or other objects of interest. Up to now, in most biology-related STED experiments, bright and photoresistant dyes with small Stokes shifts of 20-40 nm were used. The rapid progress in STED microscopy showed that organic fluorophores possessing large Stokes shifts are indispensable in multi-color super-resolution techniques. The ultimate result of the imaging relies on the optimal combination of a dye, the bio-conjugation procedure and the performance of the optical microscope. Modern bioconjugation methods, basics of STED microscopy, as well as structures and spectral properties of the presently available fluorescent markers are reviewed and discussed. In particular, the spectral properties of the commercial dyes are tabulated and correlated with the available depletion wavelengths found in STED microscopes produced by LEICA Microsytems, Abberior Instruments and Picoquant GmbH.

  19. Continuous-Wave Stimulated Emission Depletion Microscope for Imaging Actin Cytoskeleton in Fixed and Live Cells

    Directory of Open Access Journals (Sweden)

    Bhanu Neupane

    2015-09-01

    Full Text Available Stimulated emission depletion (STED microscopy provides a new opportunity to study fine sub-cellular structures and highly dynamic cellular processes, which are challenging to observe using conventional optical microscopy. Using actin as an example, we explored the feasibility of using a continuous wave (CW-STED microscope to study the fine structure and dynamics in fixed and live cells. Actin plays an important role in cellular processes, whose functioning involves dynamic formation and reorganization of fine structures of actin filaments. Frequently used confocal fluorescence and STED microscopy dyes were employed to image fixed PC-12 cells (dyed with phalloidin- fluorescein isothiocyante and live rat chondrosarcoma cells (RCS transfected with actin-green fluorescent protein (GFP. Compared to conventional confocal fluorescence microscopy, CW-STED microscopy shows improved spatial resolution in both fixed and live cells. We were able to monitor cell morphology changes continuously; however, the number of repetitive analyses were limited primarily by the dyes used in these experiments and could be improved with the use of dyes less susceptible to photobleaching. In conclusion, CW-STED may disclose new information for biological systems with a proper characteristic length scale. The challenges of using CW-STED microscopy to study cell structures are discussed.

  20. Sub-diffraction nano manipulation using STED AFM.

    Directory of Open Access Journals (Sweden)

    Jenu Varghese Chacko

    Full Text Available In the last two decades, nano manipulation has been recognized as a potential tool of scientific interest especially in nanotechnology and nano-robotics. Contemporary optical microscopy (super resolution techniques have also reached the nanometer scale resolution to visualize this and hence a combination of super resolution aided nano manipulation ineluctably gives a new perspective to the scenario. Here we demonstrate how specificity and rapid determination of structures provided by stimulated emission depletion (STED microscope can aid another microscopic tool with capability of mechanical manoeuvring, like an atomic force microscope (AFM to get topological information or to target nano scaled materials. We also give proof of principle on how high-resolution real time visualization can improve nano manipulation capability within a dense sample, and how STED-AFM is an optimal combination for this job. With these evidences, this article points to future precise nano dissections and maybe even to a nano-snooker game with an AFM tip and fluorospheres.

  1. STED microscopy detects and quantifies liquid phase separation in lipid membranes using a new far-red emitting fluorescent phosphoglycerolipid analogue.

    Science.gov (United States)

    Honigmann, Alf; Mueller, Veronika; Hell, Stefan W; Eggeling, Christian

    2013-01-01

    We have developed a bright, photostable, and far-red emitting fluorescent phosphoglycerolipid analogue to probe diffusion characteristics of lipids in membranes. The lipid analogue consists of a saturated (C18) phosphoethanolamine and a hydrophilic far-red emitting fluorescent dye (KK114) that is tethered to the head group by a long polyethylenglycol linker. In contrast to reported far-red emitting fluorescent lipid analogues, this one partitions predominantly into liquid ordered domains of phase-separated ternary bilayers. We performed fluorescence correlation spectroscopy with a super-resolution STED microscope (STED-FCS) to measure the lateral diffusion of the new lipid analogue in the liquid ordered (Lo) and disordered (Ld) phase. On a mica support, we observed micrometer large phases and found that the lipid analogue diffuses freely on all tested spatial scales (40-250 nm) in both the Ld and Lo phase with diffusion coefficients of 1.8 microm2 s(-1) and 0.7 microm2 s(-1) respectively. This indicates that the tight molecular packing of the Lo phase mainly slows down the diffusion rather than causing anomalous sub-diffusion. The same ternary mixture deposited on acid-cleaned glass forms Lo nanodomains of analogue into the nano-domains, where diffusion is slowed down. Our results suggest that STED-FCS in combination with a Lo-partitioning fluorescent lipid analogue can directly probe the presence of Lo nano-domains, which in the future should allow the study of potential lipid rafts in live-cell membranes.

  2. Mirror-enhanced super-resolution microscopy

    OpenAIRE

    2016-01-01

    Axial excitation confinement beyond the diffraction limit is crucial to the development of next-generation, super-resolution microscopy. STimulated Emission Depletion (STED) nanoscopy offers lateral super-resolution using a donut-beam depletion, but its axial resolution is still over 500 nm. Total internal reflection fluorescence microscopy is widely used for single-molecule localization, but its ability to detect molecules is limited to within the evanescent field of ~ 100 nm from the cell a...

  3. isoSTED nanoscopy with intrinsic beam alignment.

    Science.gov (United States)

    Curdt, Franziska; Herr, Simon J; Lutz, Tobias; Schmidt, Roman; Engelhardt, Johann; Sahl, Steffen J; Hell, Stefan W

    2015-11-30

    Despite the need for isotropic optical resolution in a growing number of applications, the majority of super-resolution fluorescence microscopy setups still do not attain an axial resolution comparable to that in the lateral dimensions. Three-dimensional (3D) nanoscopy implementations that employ only a single objective lens typically feature a trade-off between axial and lateral resolution. 4Pi arrangements, in which the sample is illuminated coherently through two opposing lenses, have proven their potential for rendering the resolution isotropic. However, instrument complexity due to a large number of alignment parameters has so far thwarted the dissemination of this approach. Here, we present a 4Pi-STED setup combination, also called isoSTED nanoscope, where the STED and excitation beams are intrinsically co-aligned. A highly robust and convenient 4Pi cavity allows easy handling without the need for readjustments during imaging experiments.

  4. Super-resolution imaging of ciliary microdomains in isolated olfactory sensory neurons using a custom STED microscope

    Science.gov (United States)

    Meyer, Stephanie A.; Ozbay, Baris; Restrepo, Diego; Gibson, Emily A.

    2014-03-01

    We performed super-resolution imaging of isolated olfactory sensory neurons (OSNs) using a custom-built Stimulated Emission Depletion (STED) microscope. The design for the STED microscope is based on the system developed in the laboratory of Dr. Stefan Hell1. Our system is capable of imaging with sub-diffraction limited resolution simultaneously in two color channels (at Atto 590/Atto 647N wavelengths). A single, pulsed laser source (ALP; Fianium, Inc.) generates all four laser beams, two excitation and two STED. The two STED beams are coupled into one polarization maintaining (PM) fiber and the two excitation beams into another. They are then collimated and both STED beams pass through a vortex phase plate (RPC Photonics) to allow shaping into a donut at the focus of the objective lens. The beams are then combined and sent into an inverted research microscope (IX-71; Olympus Inc.) allowing widefield epifluorescence, brightfield and DIC imaging on the same field of view as STED imaging. A fast piezo stage scans the sample during STED and confocal imaging. The fluorescent signals from the two color channels are detected with two avalanche photodiodes (APD) after appropriate spectral filtering. The resolution of the system was characterized by imaging 40 nm fluorescent beads as ~60 nm (Atto 590) and ~50 nm (Atto 647N). We performed STED imaging on immunolabeled isolated OSNs tagged at the CNGA2 and ANO2 proteins. The STED microscope allows us to resolve ciliary CNGA2 microdomains of ~54 nm that were blurred in confocal.

  5. Background suppression in fluorescence nanoscopy with stimulated emission double depletion

    Science.gov (United States)

    Gao, Peng; Prunsche, Benedikt; Zhou, Lu; Nienhaus, Karin; Nienhaus, G. Ulrich

    2017-01-01

    Stimulated emission depletion (STED) fluorescence nanoscopy is a powerful super-resolution imaging technique based on the confinement of fluorescence emission to the central subregion of an observation volume through de-excitation of fluorophores in the periphery via stimulated emission. Here, we introduce stimulated emission double depletion (STEDD) as a method to selectively remove artificial background intensity. In this approach, a first, conventional STED pulse is followed by a second, delayed Gaussian STED pulse that specifically depletes the central region, thus leaving only background. Thanks to time-resolved detection we can remove this background intensity voxel by voxel by taking the weighted difference of photons collected before and after the second STED pulse. STEDD thus yields background-suppressed super-resolved images as well as STED-based fluorescence correlation spectroscopy data. Furthermore, the proposed method is also beneficial when considering lower-power, less redshifted depletion pulses.

  6. Super-Resolution Microscopy of Cerebrospinal Fluid Biomarkers as a Tool for Alzheimer's Disease Diagnostics.

    Science.gov (United States)

    Zhang, William I; Antonios, Gregory; Rabano, Alberto; Bayer, Thomas A; Schneider, Anja; Rizzoli, Silvio O

    2015-01-01

    Alzheimer's disease (AD) is neuropathologically characterized by aggregates of amyloid-β peptides (Aβ) and tau proteins. The consensus in the AD field is that Aβ and tau should serve as diagnostic biomarkers for AD. However, their aggregates have been difficult to investigate by conventional fluorescence microscopy, since their size is below the diffraction limit (∼200 nm). To solve this, we turned to a super-resolution imaging technique, stimulated emission depletion (STED) microscopy, which has a high enough precision to allow the discrimination of low- and high-molecular weight aggregates prepared in vitro. We used STED to analyze the structural organization of Aβ and tau in cerebrospinal fluid (CSF) from 36 AD patients, 11 patients with mild cognitive impairment (MCI), and 21 controls. We measured the numbers of aggregates in the CSF samples, and the aggregate sizes and intensities. These parameters enabled us to distinguish AD patients from controls with a specificity of ∼87% and a sensitivity of ∼79% . In addition, the aggregate parameters determined with STED microscopy correlated with the severity of cognitive impairment in AD patients. Finally, these parameters may be useful as predictive tools for MCI cases. The STED parameters of two MCI patients who developed AD during the course of the study, as well as of MCI patients whose Aβ ELISA values fall within the accepted range for AD, placed them close to the AD averages. We suggest that super-resolution imaging is a promising tool for AD diagnostics.

  7. From single molecules to life: microscopy at the nanoscale.

    Science.gov (United States)

    Turkowyd, Bartosz; Virant, David; Endesfelder, Ulrike

    2016-10-01

    Super-resolution microscopy is the term commonly given to fluorescence microscopy techniques with resolutions that are not limited by the diffraction of light. Since their conception a little over a decade ago, these techniques have quickly become the method of choice for many biologists studying structures and processes of single cells at the nanoscale. In this review, we present the three main approaches used to tackle the diffraction barrier of ∼200 nm: stimulated-emission depletion (STED) microscopy, structured illumination microscopy (SIM), and single-molecule localization microscopy (SMLM). We first present a theoretical overview of the techniques and underlying physics, followed by a practical guide to all of the facets involved in designing a super-resolution experiment, including an approachable explanation of the photochemistry involved, labeling methods available, and sample preparation procedures. Finally, we highlight some of the most exciting recent applications of and developments in these techniques, and discuss the outlook for this field. Graphical Abstract Super-resolution microscopy techniques. Working principles of the common approaches stimulated-emission depletion (STED) microscopy, structured illumination microscopy (SIM), and single-molecule localization microscopy (SMLM).

  8. Stimulated scintillation emission depletion X-ray imaging.

    Science.gov (United States)

    Alekhin, M S; Patton, G; Dujardin, C; Douissard, P-A; Lebugle, M; Novotny, L; Stampanoni, M

    2017-01-23

    X-ray microtomography is a widely applied tool for noninvasive structure investigations. The related detectors are usually based on a scintillator screen for the fast in situ conversion of an X-ray image into an optical image. Spatial resolution of the latter is fundamentally diffraction limited. In this work, we introduce stimulated scintillation emission depletion (SSED) X-ray imaging where, similar to stimulated emission depletion (STED) microscopy, a depletion beam is applied to the scintillator screen to overcome the diffraction limit. The requirements for the X-ray source, the X-ray flux, the scintillator screen, and the STED beam were evaluated. Fundamental spatial resolution limits due to the spread of absorbed X-ray energy were estimated with Monte Carlo simulations. The SSED proof-of-concept experiments demonstrated 1) depletion of X-ray excited scintillation, 2) partial confinement of scintillating regions to sub-diffraction sized volumes, and 3) improvement of the imaging contrast by applying SSED.

  9. Super-resolution optical microscopy of lipid plasma membrane dynamics.

    Science.gov (United States)

    Eggeling, Christian

    2015-01-01

    Plasma membrane dynamics are an important ruler of cellular activity, particularly through the interaction and diffusion dynamics of membrane-embedded proteins and lipids. FCS (fluorescence correlation spectroscopy) on an optical (confocal) microscope is a popular tool for investigating such dynamics. Unfortunately, its full applicability is constrained by the limited spatial resolution of a conventional optical microscope. The present chapter depicts the combination of optical super-resolution STED (stimulated emission depletion) microscopy with FCS, and why it is an important tool for investigating molecular membrane dynamics in living cells. Compared with conventional FCS, the STED-FCS approach demonstrates an improved possibility to distinguish free from anomalous molecular diffusion, and thus to give new insights into lipid-protein interactions and the traditional lipid 'raft' theory.

  10. The 2015 super-resolution microscopy roadmap

    Science.gov (United States)

    Hell, Stefan W.; Sahl, Steffen J.; Bates, Mark; Zhuang, Xiaowei; Heintzmann, Rainer; Booth, Martin J.; Bewersdorf, Joerg; Shtengel, Gleb; Hess, Harald; Tinnefeld, Philip; Honigmann, Alf; Jakobs, Stefan; Testa, Ilaria; Cognet, Laurent; Lounis, Brahim; Ewers, Helge; Davis, Simon J.; Eggeling, Christian; Klenerman, David; Willig, Katrin I.; Vicidomini, Giuseppe; Castello, Marco; Diaspro, Alberto; Cordes, Thorben

    2015-11-01

    Far-field optical microscopy using focused light is an important tool in a number of scientific disciplines including chemical, (bio)physical and biomedical research, particularly with respect to the study of living cells and organisms. Unfortunately, the applicability of the optical microscope is limited, since the diffraction of light imposes limitations on the spatial resolution of the image. Consequently the details of, for example, cellular protein distributions, can be visualized only to a certain extent. Fortunately, recent years have witnessed the development of ‘super-resolution’ far-field optical microscopy (nanoscopy) techniques such as stimulated emission depletion (STED), ground state depletion (GSD), reversible saturated optical (fluorescence) transitions (RESOLFT), photoactivation localization microscopy (PALM), stochastic optical reconstruction microscopy (STORM), structured illumination microscopy (SIM) or saturated structured illumination microscopy (SSIM), all in one way or another addressing the problem of the limited spatial resolution of far-field optical microscopy. While SIM achieves a two-fold improvement in spatial resolution compared to conventional optical microscopy, STED, RESOLFT, PALM/STORM, or SSIM have all gone beyond, pushing the limits of optical image resolution to the nanometer scale. Consequently, all super-resolution techniques open new avenues of biomedical research. Because the field is so young, the potential capabilities of different super-resolution microscopy approaches have yet to be fully explored, and uncertainties remain when considering the best choice of methodology. Thus, even for experts, the road to the future is sometimes shrouded in mist. The super-resolution optical microscopy roadmap of Journal of Physics D: Applied Physics addresses this need for clarity. It provides guidance to the outstanding questions through a collection of short review articles from experts in the field, giving a thorough

  11. Suppression of resonance Raman scattering via ground state depletion towards sub-diffraction-limited label-free microscopy

    NARCIS (Netherlands)

    Rieger, S.; Fischedick, M.; Boller, K-J.; Fallnich, C.

    2016-01-01

    We report on the first experimental demonstration of the suppression of spontaneous Raman scattering via ground state depletion. The concept of Raman suppression can be used to achieve sub-diffraction-limited resolution in label-free microscopy by exploiting spatially selective signal suppression wh

  12. Effects of cholesterol depletion on membrane nanostructure in MCF-7 cells by atomic force microscopy

    Science.gov (United States)

    Wang, Yuhua; Jiang, Ningcheng; Shi, Aisi; Zheng, Liqin; Yang, Hongqin; Xie, Shusen

    2017-02-01

    The cell membrane is composed of phospholipids, glycolipids, cholesterol and proteins that are dynamic and heterogeneous distributed in the bilayer structure and many researches have showed that the plasma membrane in eukaryotic cells contains microdomains termed "lipid raft" in which cholesterol, sphingolipids and specific membrane proteins are enriched. Cholesterol extraction induced lipid raft disruption is one of the most widely used methods for lipid raft research and MβCD is a type of solvent to extract the cholesterol from cell membranes. In this study, the effect of MβCD treatment on the membrane nanostructure in MCF-7 living cells was investigated by atomic force microscopy. Different concentrations of MβCD were selected to deplete cholesterol for 30 min and the viability of cells was tested by MTT assay to obtain the optimal concentration. Then the nanostructure of the cell membrane was detected. The results show that an appropriate concentration of MβCD can induce the alteration of cell membranes nanostructure and the roughness of membrane surface decreases significantly. This may indicate that microdomains of the cell membrane disappear and the cell membrane appears more smoothly. Cholesterol can affect nanostructure and inhomogeneity of the plasma membrane in living cells.

  13. Multiphoton STED and FRET in human skin: Resolving the skin barrier

    DEFF Research Database (Denmark)

    Antonescu, Irina; Dreier, Jes; Brewer, Jonathan R.

    Understanding the penetration properties of substances across biological bar- riers and membranes is vital for many areas of research. In the case of human skin, the barrier is primarily found in the stratum corneum and consists of protein-enriched cells surrounded by a lipid membrane -enriched...... excited STED and Forster Resonance Energy Transfer (FRET) microscopy to probe the structure of human skin. Super resolution optical microscopy enables resolving structures in the skin below to 60 nm allowing visualization of the stratum corneum intercellular lipid matrix and individual proteins...

  14. Super-resolution Microscopy in Plant Cell Imaging.

    Science.gov (United States)

    Komis, George; Šamajová, Olga; Ovečka, Miroslav; Šamaj, Jozef

    2015-12-01

    Although the development of super-resolution microscopy methods dates back to 1994, relevant applications in plant cell imaging only started to emerge in 2010. Since then, the principal super-resolution methods, including structured-illumination microscopy (SIM), photoactivation localization microscopy (PALM), stochastic optical reconstruction microscopy (STORM), and stimulated emission depletion microscopy (STED), have been implemented in plant cell research. However, progress has been limited due to the challenging properties of plant material. Here we summarize the basic principles of existing super-resolution methods and provide examples of applications in plant science. The limitations imposed by the nature of plant material are reviewed and the potential for future applications in plant cell imaging is highlighted.

  15. Scanning STED-FCS reveals spatiotemporal heterogeneity of lipid interaction in the plasma membrane of living cells

    Science.gov (United States)

    Honigmann, Alf; Mueller, Veronika; Ta, Haisen; Schoenle, Andreas; Sezgin, Erdinc; Hell, Stefan W.; Eggeling, Christian

    2014-11-01

    The interaction of lipids and proteins plays an important role in plasma membrane bioactivity, and much can be learned from their diffusion characteristics. Here we present the combination of super-resolution STED microscopy with scanning fluorescence correlation spectroscopy (scanning STED-FCS, sSTED-FCS) to characterize the spatial and temporal heterogeneity of lipid interactions. sSTED-FCS reveals transient molecular interaction hotspots for a fluorescent sphingolipid analogue. The interaction sites are smaller than 80 nm in diameter and lipids are transiently trapped for several milliseconds in these areas. In comparison, newly developed fluorescent phospholipid and cholesterol analogues with improved phase-partitioning properties show more homogenous diffusion, independent of the preference for liquid-ordered or disordered membrane environments. Our results do not support the presence of nanodomains based on lipid-phase separation in the basal membrane of our cultured nonstimulated cells, and show that alternative interactions are responsible for the strong local trapping of our sphingolipid analogue.

  16. Two-photon STED spectral determination for a new V-shaped organic fluorescent probe with efficient two-photon absorption.

    Science.gov (United States)

    Belfield, Kevin D; Bondar, Mykhailo V; Morales, Alma R; Padilha, Lazaro A; Przhonska, Olga V; Wang, Xuhua

    2011-10-24

    Two-photon stimulated emission depletion (STED) cross sections were determined over a broad spectral range for a novel two-photon absorbing organic molecule, representing the first such report. The synthesis, comprehensive linear photophysical, two-photon absorption (2PA), and stimulated emission properties of a new fluorene-based compound, (E)-2-{3-[2-(7-(diphenylamino)-9,9-diethyl-9H-fluoren-2-yl)vinyl]-5-methyl-4-oxocyclohexa-2,5-dienylidene} malononitrile (1), are presented. Linear spectral parameters, including excitation anisotropy and fluorescence lifetimes, were obtained over a broad range of organic solvents at room temperature. The degenerate two-photon absorption (2PA) spectrum of 1 was determined with a combination of the direct open-aperture Z-scan and relative two-photon-induced fluorescence methods using 1 kHz femtosecond excitation. The maximum value of the 2PA cross section ~1700 GM was observed in the main, long wavelength, one-photon absorption band. One- and two-photon stimulated emission spectra of 1 were obtained over a broad spectral range using a femtosecond pump-probe technique, resulting in relatively high two-photon stimulated emission depletion cross sections (~1200 GM). A potential application of 1 in bioimaging was demonstrated through one- and two-photon fluorescence microscopy images of HCT 116 cells incubated with micelle-encapsulated dye.

  17. Convergence of lateral dynamic measurements in the plasma membrane of live cells from single particle tracking and STED-FCS

    Science.gov (United States)

    Lagerholm, B. Christoffer; Andrade, Débora M.; Clausen, Mathias P.; Eggeling, Christian

    2017-02-01

    Fluorescence correlation spectroscopy (FCS) in combination with the super-resolution imaging method STED (STED-FCS), and single-particle tracking (SPT) are able to directly probe the lateral dynamics of lipids and proteins in the plasma membrane of live cells at spatial scales much below the diffraction limit of conventional microscopy. However, a major disparity in interpretation of data from SPT and STED-FCS remains, namely the proposed existence of a very fast (unhindered) lateral diffusion coefficient, ⩾5 µm2 s-1, in the plasma membrane of live cells at very short length scales, ≈⩽ 100 nm, and time scales, ≈1-10 ms. This fast diffusion coefficient has been advocated in several high-speed SPT studies, for lipids and membrane proteins alike, but the equivalent has not been detected in STED-FCS measurements. Resolving this ambiguity is important because the assessment of membrane dynamics currently relies heavily on SPT for the determination of heterogeneous diffusion. A possible systematic error in this approach would thus have vast implications in this field. To address this, we have re-visited the analysis procedure for SPT data with an emphasis on the measurement errors and the effect that these errors have on the measurement outputs. We subsequently demonstrate that STED-FCS and SPT data, following careful consideration of the experimental errors of the SPT data, converge to a common interpretation which for the case of a diffusing phospholipid analogue in the plasma membrane of live mouse embryo fibroblasts results in an unhindered, intra-compartment, diffusion coefficient of  ≈0.7-1.0 µm2 s-1, and a compartment size of about 100-150 nm.

  18. 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.

  19. Dissection of mechanical force in living cells by super-resolved traction force microscopy.

    Science.gov (United States)

    Colin-York, Huw; Eggeling, Christian; Fritzsche, Marco

    2017-04-01

    Cells continuously exert or respond to mechanical force. Measurement of these nanoscale forces is a major challenge in cell biology; yet such measurement is essential to the understanding of cell regulation and function. Current methods for examining mechanical force generation either necessitate dedicated equipment or limit themselves to coarse-grained force measurements on the micron scale. In this protocol, we describe stimulated emission depletion traction force microscopy-STED-TFM (STFM), which allows higher sampling of the forces generated by the cell than conventional TFM, leading to a twofold increase in spatial resolution (of up to 500 nm). The procedure involves the preparation of functionalized polyacrylamide gels loaded with fluorescent beads, as well as the acquisition of STED images and their analysis. We illustrate the approach using the example of HeLa cells expressing paxillin-EGFP to visualize focal adhesions. Our protocol uses widely available laser-scanning confocal microscopes equipped with a conventional STED laser, open-source software and common molecular biology techniques. The entire STFM experiment preparation, data acquisition and analysis require 2-3 d and could be completed by someone with minimal experience in molecular biology or biophysics.

  20. Diffusion of lipids and GPI-anchored proteins in actin-free plasma membrane vesicles measured by STED-FCS

    DEFF Research Database (Denmark)

    Schneider, Falk; Waithe, Dominic; Clausen, Mathias P

    2017-01-01

    Diffusion and interaction dynamics of molecules at the plasma membrane play an important role in cellular signalling, and they are suggested to be strongly associated with the actin cytoskeleton. Here, we utilise super-resolution STED microscopy combined with fluorescence correlation spectroscopy...... (STED-FCS) to access and compare the diffusion characteristics of fluorescent lipid analogues and GPI-anchored proteins (GPI-APs) in the live cell plasma membrane and in actin cytoskeleton-free cell-derived giant plasma membrane vesicles (GPMVs). Hindered diffusion of phospholipids and sphingolipids...... forming immobile clusters, both of which disappear in GPMVs. Our data underline the crucial role of the actin cortex in maintaining hindered diffusion modes of many but not all of the membrane molecules, and highlight a powerful experimental approach to decipher specific influences on molecular plasma...

  1. Klima, apokalypse og en topos om sted

    DEFF Research Database (Denmark)

    Nielsen, Esben Bjerggaard

    2013-01-01

    Klimadebatten er fuld af forudsigelser om fremtiden og lurende katastrofe. Al Gore har eksempelvis gjort brug af en apokalyptisk fortælling i sin klimaretorik. Tid er en vigtig topos i denne type retorik. Forfatteren viser her, hvordan skiftet til en topos om Sted forandrer den klassiske apokalyp......Klimadebatten er fuld af forudsigelser om fremtiden og lurende katastrofe. Al Gore har eksempelvis gjort brug af en apokalyptisk fortælling i sin klimaretorik. Tid er en vigtig topos i denne type retorik. Forfatteren viser her, hvordan skiftet til en topos om Sted forandrer den klassiske...

  2. STED Nanoscopy Reveals the Ubiquity of Subcortical Cytoskeleton Periodicity in Living Neurons

    Directory of Open Access Journals (Sweden)

    Elisa D’Este

    2015-03-01

    Full Text Available In the axons of cultured hippocampal neurons, actin forms various structures, including bundles, patches (involved in the preservation of neuronal polarity, and a recently reported periodic ring-like structure. Nevertheless, the overlaying organization of actin in neurons and in the axon initial segment (AIS is still unclear, due mainly to a lack of adequate imaging methods. By harnessing live-cell stimulated emission depletion (STED nanoscopy and the fluorescent probe SiR-Actin, we show that the periodic subcortical actin structure is in fact present in both axons and dendrites. The periodic cytoskeleton organization is also found in the peripheral nervous system, specifically at the nodes of Ranvier. The actin patches in the AIS co-localize with pre-synaptic markers. Cytosolic actin organization strongly depends on the developmental stage and subcellular localization. Altogether, the results of this study reveal unique neuronal cytoskeletal features.

  3. STED nanoscopy reveals the ubiquity of subcortical cytoskeleton periodicity in living neurons.

    Science.gov (United States)

    D'Este, Elisa; Kamin, Dirk; Göttfert, Fabian; El-Hady, Ahmed; Hell, Stefan W

    2015-03-03

    In the axons of cultured hippocampal neurons, actin forms various structures, including bundles, patches (involved in the preservation of neuronal polarity), and a recently reported periodic ring-like structure. Nevertheless, the overlaying organization of actin in neurons and in the axon initial segment (AIS) is still unclear, due mainly to a lack of adequate imaging methods. By harnessing live-cell stimulated emission depletion (STED) nanoscopy and the fluorescent probe SiR-Actin, we show that the periodic subcortical actin structure is in fact present in both axons and dendrites. The periodic cytoskeleton organization is also found in the peripheral nervous system, specifically at the nodes of Ranvier. The actin patches in the AIS co-localize with pre-synaptic markers. Cytosolic actin organization strongly depends on the developmental stage and subcellular localization. Altogether, the results of this study reveal unique neuronal cytoskeletal features.

  4. Aptamer Stainings for Super-resolution Microscopy.

    Science.gov (United States)

    de Castro, Maria Angela Gomes; Rammner, Burkhard; Opazo, Felipe

    2016-01-01

    Fluorescence microscopy is an invaluable tool to visualize molecules in their biological context with ease and flexibility. However, studies using conventional light microscopy have been limited to the resolution that light diffraction allows (i.e., ~200 nm). This limitation has been recently circumvented by several types of advanced fluorescence microscopy techniques, which have achieved resolutions of up to ~10 nm. The resulting enhanced imaging precision has helped to find important cellular details that were not visible using diffraction-limited instruments. However, it has also revealed that conventional stainings using large affinity tags, such as antibodies, are not accurate enough for these imaging techniques. Since aptamers are substantially smaller than antibodies, they could provide a real advantage in super-resolution imaging. Here we compare the live staining of transferrin receptors (TfnR) obtained with different fluorescently labeled affinity probes: aptamers, specific monoclonal antibodies, or the natural receptor ligand transferrin. We observed negligible differences between these staining strategies when imaging is performed with conventional light microscopy (i.e., laser scanning confocal microscopy). However, a clear superiority of the aptamer tag over antibodies became apparent in super-resolved images obtained with stimulated emission depletion (STED) microscopy.

  5. Interfacing 3D magnetic twisting cytometry with confocal fluorescence microscopy to image force responses in living cells.

    Science.gov (United States)

    Zhang, Yuejin; Wei, Fuxiang; Poh, Yeh-Chuin; Jia, Qiong; Chen, Junjian; Chen, Junwei; Luo, Junyu; Yao, Wenting; Zhou, Wenwen; Huang, Wei; Yang, Fang; Zhang, Yao; Wang, Ning

    2017-07-01

    Cells and tissues can undergo a variety of biological and structural changes in response to mechanical forces. Only a few existing techniques are available for quantification of structural changes at high resolution in response to forces applied along different directions. 3D-magnetic twisting cytometry (3D-MTC) is a technique for applying local mechanical stresses to living cells. Here we describe a protocol for interfacing 3D-MTC with confocal fluorescence microscopy. In 3D-MTC, ferromagnetic beads are bound to the cell surface via surface receptors, followed by their magnetization in any desired direction. A magnetic twisting field in a different direction is then applied to generate rotational shear stresses in any desired direction. This protocol describes how to combine magnetic-field-induced mechanical stimulation with confocal fluorescence microscopy and provides an optional extension for super-resolution imaging using stimulated emission depletion (STED) nanoscopy. This technology allows for rapid real-time acquisition of a living cell's mechanical responses to forces via specific receptors and for quantifying structural and biochemical changes in the same cell using confocal fluorescence microscopy or STED. The integrated 3D-MTC-microscopy platform takes ∼20 d to construct, and the experimental procedures require ∼4 d when carried out by a life sciences graduate student.

  6. Super-Resolved Traction Force Microscopy (STFM).

    Science.gov (United States)

    Colin-York, Huw; Shrestha, Dilip; Felce, James H; Waithe, Dominic; Moeendarbary, Emad; Davis, Simon J; Eggeling, Christian; Fritzsche, Marco

    2016-04-13

    Measuring small forces is a major challenge in cell biology. Here we improve the spatial resolution and accuracy of force reconstruction of the well-established technique of traction force microscopy (TFM) using STED microscopy. The increased spatial resolution of STED-TFM (STFM) allows a greater than 5-fold higher sampling of the forces generated by the cell than conventional TFM, accessing the nano instead of the micron scale. This improvement is highlighted by computer simulations and an activating RBL cell model system.

  7. Measuring Exciton Diffusion in Conjugated Polymer Films with Super-resolution Microscopy

    Science.gov (United States)

    Penwell, Samuel; Ginsberg, Lucas; Noriega Manez, Rodrigo; Ginsberg, Naomi

    2015-03-01

    Conjugated polymers are highly tunable organic semiconductors, which can be solution processed to form thin films, making them prime candidates for organic photovoltaic devices. One of the most important parameters in a conjugated polymer solar cell is the exciton diffusion length, which depends on intermolecular couplings, and is typically on the order of 10 nm. This mean exciton migration can vary dramatically between films and within a single film due to heterogeneities in morphology on length scales of 10's to 100's nm. To study the variability of exciton diffusion and morphology within individual conjugated polymer films, we are adapting stimulated emission depletion microscopy. STED is typically used in biology with well-engineered fluorescent labels or on NV-centers in diamond. I will, however, describe how we have demonstrated STED in conjugated polymer films of MEH-PPV and CN-PPV by taking care to first understand the film's photophysical properties. This new approach provides a way to study exciton diffusion by utilizing subdiffraction optical excitation volumes. In this way, we will obtain a spatiotemporal map of exciton distributions that will help to correlate the energetic landscape to film morphology at the nanoscale. This research is supported in part by the Department of Energy Office of Science Graduate Fellowship Program (DOE SCGF), made possible in part by the American Recovery and Reinvestment Act of 2009, administered by ORISE-ORAU under Contract No. DE-AC05-06.

  8. Multicolour nanoscopy of fixed and living cells with a single STED beam and hyperspectral detection

    Science.gov (United States)

    Winter, Franziska R.; Loidolt, Maria; Westphal, Volker; Butkevich, Alexey N.; Gregor, Carola; Sahl, Steffen J.; Hell, Stefan W.

    2017-04-01

    The extension of fluorescence nanoscopy to larger numbers of molecular species concurrently visualized by distinct markers is of great importance for advanced biological applications. To date, up to four markers had been distinguished in STED experiments featuring comparatively elaborate imaging schemes and optical setups, and exploiting various properties of the fluorophores. Here we present a simple yet versatile STED design for multicolour imaging below the diffraction limit. A hyperspectral detection arrangement (hyperSTED) collects the fluorescence in four spectral channels, allowing the separation of four markers with only one excitation wavelength and a single STED beam. Unmixing of the different marker signals based on the simultaneous readout of all channels is performed with a non-negative matrix factorization algorithm. We illustrate the approach showing four-colour nanoscopy of fixed and living cellular samples.

  9. Advanced Microscopy of Microbial Cells

    DEFF Research Database (Denmark)

    Haagensen, Janus Anders Juul; Regenberg, Birgitte; Sternberg, Claus

    2011-01-01

    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......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...

  10. Super-resolution imaging of ciliary microdomains in isolated olfactory sensory neurons using a custom two-color stimulated emission depletion microscope

    Science.gov (United States)

    Meyer, Stephanie A.; Ozbay, Baris N.; Potcoava, Mariana; Salcedo, Ernesto; Restrepo, Diego; Gibson, Emily A.

    2016-06-01

    We performed stimulated emission depletion (STED) imaging of isolated olfactory sensory neurons (OSNs) using a custom-built microscope. The STED microscope uses a single pulsed laser to excite two separate fluorophores, Atto 590 and Atto 647N. A gated timing circuit combined with temporal interleaving of the different color excitation/STED laser pulses filters the two channel detection and greatly minimizes crosstalk. We quantified the instrument resolution to be ˜81 and ˜44 nm, for the Atto 590 and Atto 647N channels. The spatial separation between the two channels was measured to be under 10 nm, well below the resolution limit. The custom-STED microscope is incorporated onto a commercial research microscope allowing brightfield, differential interference contrast, and epifluorescence imaging on the same field of view. We performed immunolabeling of OSNs in mice to image localization of ciliary membrane proteins involved in olfactory transduction. We imaged Ca2+-permeable cyclic nucleotide gated (CNG) channel (Atto 594) and adenylyl cyclase type III (ACIII) (Atto 647N) in distinct cilia. STED imaging resolved well-separated subdiffraction limited clusters for each protein. We quantified the size of each cluster to have a mean value of 88±48 nm and 124±43 nm, for CNG and ACIII, respectively. STED imaging showed separated clusters that were not resolvable in confocal images.

  11. Does super-resolution fluorescence microscopy obsolete previous microscopic approaches to protein co-localization?

    Science.gov (United States)

    MacDonald, Laura; Baldini, Giulia; Storrie, Brian

    2015-01-01

    Conventional microscopy techniques, namely, the confocal microscope or deconvolution processes, are resolution limited to approximately 200-250 nm by the diffraction properties of light as developed by Ernst Abbe in 1873. This diffraction limit is appreciably above the size of most multi-protein complexes, which are typically 20-50 nm in diameter. In the mid-2000s, biophysicists moved beyond the diffraction barrier by structuring the illumination pattern and then applying mathematical principles and algorithms to allow a resolution of approximately 100 nm, sufficient to address protein subcellular co-localization questions. This "breaking" of the diffraction barrier, affording resolution beyond 200 nm, is termed super-resolution microscopy. More recent approaches include single-molecule localization (such as photoactivated localization microscopy (PALM)/stochastic optical reconstruction microscopy (STORM)) and point spread function engineering (such as stimulated emission depletion (STED) microscopy). In this review, we explain basic principles behind currently commercialized super-resolution setups and address advantages and considerations in applying these techniques to protein co-localization in biological systems.

  12. Convergence of lateral dynamic measurements in the plasma membrane of live cells from single particle tracking and STED-FCS

    DEFF Research Database (Denmark)

    Lagerholm, B. Christoffer; Andrade, Débora M.; Clausen, Mathias P.

    2017-01-01

    Fluorescence correlation spectroscopy (FCS) in combination with the super-resolution imaging method STED (STED-FCS), and single-particle tracking (SPT) are able to directly probe the lateral dynamics of lipids and proteins in the plasma membrane of live cells at spatial scales much below the diff...... embryo fibroblasts results in an unhindered, intra-compartment, diffusion coefficient of ≈0.7-1.0 μm2 s-1, and a compartment size of about 100-150 nm....

  13. Differential localization of SAP102 and PSD-95 is revealed in hippocampal spines using super-resolution light microscopy.

    Science.gov (United States)

    Zheng, Chan-Ying; Wang, Ya-Xia; Kachar, Bechara; Petralia, Ronald S

    2011-01-01

    Synapse-associated protein 102 (SAP102) and postsynaptic density 95 (PSD-95) are two major cytoskeleton proteins in the postsynaptic density (PSD). Both of them belong to the membrane-associated guanylate kinase (MAGUK) family, which clusters and anchors glutamate receptors and other proteins at synapses. In our previous study, we found that SAP102 and PSD-95 have different distributions, using combined light/electron microscopy (LM/EM) methods.1 Here, we double labeled endogenous SAP102 and PSD-95 in mature hippocampal neurons, and then took images by two different kinds of super resolution microscopy-Stimulated Emission Depletion microscopy (STED) and DeltaVision OMX 3D super resolution microscopy. We found that our 2D and 3D super resolution data were consistent with our previous LM/EM data, showing significant differences in the localization of SAP102 and PSD-95 in spines: SAP102 is distributed in both the PSD and cytoplasm of spines, while PSD-95 is concentrated only in the PSD area. These results indicate functional differences between SAP102 and PSD-95 in synaptic organization and plasticity.

  14. Sub-Diffraction Nano Manipulation Using STED AFM

    OpenAIRE

    Jenu Varghese Chacko; Claudio Canale; Benjamin Harke; Alberto Diaspro

    2013-01-01

    In the last two decades, nano manipulation has been recognized as a potential tool of scientific interest especially in nanotechnology and nano-robotics. Contemporary optical microscopy (super resolution) techniques have also reached the nanometer scale resolution to visualize this and hence a combination of super resolution aided nano manipulation ineluctably gives a new perspective to the scenario. Here we demonstrate how specificity and rapid determination of structures provided by stimula...

  15. Aptamers provide superior stainings of cellular receptors studied under super-resolution microscopy

    Science.gov (United States)

    Höbartner, Claudia

    2017-01-01

    Continuous improvements in imaging techniques are challenging biologists to search for more accurate methods to label cellular elements. This is particularly relevant for diffraction-unlimited fluorescence imaging, where the perceived resolution is affected by the size of the affinity probes. This is evident when antibodies, which are 10–15 nm in size, are used. Previously it has been suggested that RNA aptamers (~3 nm) can be used to detect cellular proteins under super-resolution imaging. However, a direct comparison between several aptamers and antibodies is needed, to clearly show the advantages and/or disadvantages of the different probes. Here we have conducted such a comparative study, by testing several aptamers and antibodies using stimulated emission depletion microscopy (STED). We have targeted three membrane receptors, EGFR, ErbB2 and Epha2, which are relevant to human health, and recycle between plasma membrane and intracellular organelles. Our results suggest that the aptamers can reveal more epitopes than most antibodies, thus providing a denser labeling of the stained structures. Moreover, this improves the overall quality of the information that can be extracted from the images. We conclude that aptamers could become useful fluorescent labeling tools for light microscopy and super-resolution imaging, and that their development for novel targets is imperative. PMID:28235049

  16. Note on the classification of super-resolution in far-field microscopy and information theory

    CERN Document Server

    Passon, Oliver

    2016-01-01

    In recent years several far-field microscopy techniques have been developed which manage to overcome the diffraction limit of resolution. A unifying classification scheme for them is clearly desirable. We argue that existing schemes based on the information capacity of the optical system can not easily be extended to cover e.g., STED microscopy or techniques based on single molecule imaging. We suggest a classification based on a reconstruction of the Abbe limit.

  17. Note on the classification of super-resolution in far-field microscopy and information theory

    Science.gov (United States)

    Passon, Oliver; Grebe-Ellis, Johannes

    2016-07-01

    In recent years several far-field microscopy techniques have been developed which manage to overcome the diffraction limit of resolution. A unifying classification scheme for them is clearly desirable. We argue that existing schemes based on the information capacity of the optical system can not easily be extended to cover e.g., STED microscopy or techniques based on single molecule imaging. We suggest a classification based on a reconstruction of the Abbe limit.

  18. 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

  19. Super-resolution stimulated emission depletion imaging of slit diaphragm proteins in optically cleared kidney tissue.

    Science.gov (United States)

    Unnersjö-Jess, David; Scott, Lena; Blom, Hans; Brismar, Hjalmar

    2016-01-01

    The glomerular filtration barrier, consisting of podocyte foot processes with bridging slit diaphragm, glomerular basement membrane, and endothelium, is a key component for renal function. Previously, the subtlest elements of the filtration barrier have only been visualized using electron microscopy. However, electron microscopy is mostly restricted to ultrathin two-dimensional samples, and the possibility to simultaneously visualize multiple different proteins is limited. Therefore, we sought to implement a super-resolution immunofluorescence microscopy protocol for the study of the filtration barrier in the kidney. Recently, several optical clearing methods have been developed making it possible to image through large volumes of tissue and even whole organs using light microscopy. Here we found that hydrogel-based optical clearing is a beneficial tool to study intact renal tissue at the nanometer scale. When imaging samples using super-resolution STED microscopy, the staining quality was critical in order to assess correct nanoscale information. The signal-to-noise ratio and immunosignal homogeneity were both improved in optically cleared tissue. Thus, STED of slit diaphragms in fluorescently labeled, optically cleared, intact kidney samples is a new tool for studying the glomerular filtration barrier in health and disease.

  20. Dissecting the actin cortex density and membrane-cortex distance in living cells by super-resolution microscopy

    Science.gov (United States)

    Clausen, M. P.; Colin-York, H.; Schneider, F.; Eggeling, C.; Fritzsche, M.

    2017-02-01

    Nanoscale spacing between the plasma membrane and the underlying cortical actin cytoskeleton profoundly modulates cellular morphology, mechanics, and function. Measuring this distance has been a key challenge in cell biology. Current methods for dissecting the nanoscale spacing either limit themselves to complex survey design using fixed samples or rely on diffraction-limited fluorescence imaging whose spatial resolution is insufficient to quantify distances on the nanoscale. Using dual-color super-resolution STED (stimulated-emission-depletion) microscopy, we here overcome this challenge and accurately measure the density distribution of the cortical actin cytoskeleton and the distance between the actin cortex and the membrane in live Jurkat T-cells. We found an asymmetric cortical actin density distribution with a mean width of 230 (+105/-125) nm. The spatial distances measured between the maximum density peaks of the cortex and the membrane were bi-modally distributed with mean values of 50  ±  15 nm and 120  ±  40 nm, respectively. Taken together with the finite width of the cortex, our results suggest that in some regions the cortical actin is closer than 10 nm to the membrane and a maximum of 20 nm in others.

  1. The Number of Accumulated Photons and the Quality of Stimulated Emission Depletion Lifetime Images

    Energy Technology Data Exchange (ETDEWEB)

    Syed, Aleem [Ames Laboratory; Lesoine, Michael D [Ames Laboratory; Bhattacharjee, Ujjal [Ames Laboratory; Petrich, Jacob W [Ames Laboratory; Smith, Emily A [Ames Laboratory

    2014-03-03

    Time binning is used to increase the number of photon counts in the peak channel of stimulated emission depletion (STED) fluorescence lifetime decay curves to determine how it affects the resulting lifetime image. The fluorescence lifetime of the fluorophore, Alexa Fluor 594 phalloidin, bound to F-actin is probed in cultured S2 cells at a spatial resolution of ~40 nm. This corresponds to a tenfold smaller probe volume compared to confocal imaging, and a reduced number of photons contributing to the signal. Pixel-by-pixel fluorescence lifetime measurements and error analysis show that an average of 40 ± 30 photon counts in the peak channel with a signal-to-noise ratio of 20 is enough to calculate a reliable fluorescence lifetime from a single exponential fluorescence decay. No heterogeneity in the actin cytoskeleton in different regions of the cultured cells was measured in the 40- to 400-nm spatial regime.

  2. [Hepatomioneuropathy secondary to mitochondrial DNA depletion].

    Science.gov (United States)

    Blanco-Barca, M O; Gómez-Lado, C; Campos-González, Y; Castro-Gago, M

    2007-04-01

    Mitochondrial DNA depletion (mtDNA) is an highly heterogeneous condition characterized by a decreased number of mtDNA copies. The patient is a 22-month-old girl with generalized hypotonia, marked weakness, respiratory failure, arterial hypertension, hyperlactacidemia, hepatosplenomegaly and mild hypertransaminasemia without hepatic failure neither hypoketotic hypoglycemia. Electromyographic findings were consistent with neuromyopathy and muscle biopsy suggested a neurogenic atrophy. Electron microscopy revealed lipid droplets, subsarcolemmal accumulation of mitochondrias and glycogen granules. Respiratory chain enzime activities were normal. Genetic study in muscle showed mtDNA depletion, and the diagnosis of spinal muscular atrophy caused by survival motoneuron gene deletion was excluded. This case might be a novel phenotype of mtDNA depletion which could be named hepatomioneuropatyc form. A normal result of respiratory chain enzimes in muscle doesn't excluded mtDNA depletion.

  3. B-Spline potential function for maximum a-posteriori image reconstruction in fluorescence microscopy

    Directory of Open Access Journals (Sweden)

    Shilpa Dilipkumar

    2015-03-01

    Full Text Available An iterative image reconstruction technique employing B-Spline potential function in a Bayesian framework is proposed for fluorescence microscopy images. B-splines are piecewise polynomials with smooth transition, compact support and are the shortest polynomial splines. Incorporation of the B-spline potential function in the maximum-a-posteriori reconstruction technique resulted in improved contrast, enhanced resolution and substantial background reduction. The proposed technique is validated on simulated data as well as on the images acquired from fluorescence microscopes (widefield, confocal laser scanning fluorescence and super-resolution 4Pi microscopy. A comparative study of the proposed technique with the state-of-art maximum likelihood (ML and maximum-a-posteriori (MAP with quadratic potential function shows its superiority over the others. B-Spline MAP technique can find applications in several imaging modalities of fluorescence microscopy like selective plane illumination microscopy, localization microscopy and STED.

  4. Perspectives in Super-resolved Fluorescence Microscopy: What comes next?

    Science.gov (United States)

    Cremer, Christoph; Birk, Udo

    2016-04-01

    The Nobel Prize in Chemistry 2014 has been awarded to three scientists involved in the development of STED and PALM super-resolution fluorescence microscopy (SRM) methods. They have proven that it is possible to overcome the hundred year old theoretical limit for the resolution potential of light microscopy (of about 200 nm for visible light), which for decades has precluded a direct glimpse of the molecular machinery of life. None of the present-day super-resolution techniques have invalidated the Abbe limit for light optical detection; however, they have found clever ways around it. In this report, we discuss some of the challenges still to be resolved before arising SRM approaches will be fit to bring about the revolution in Biology and Medicine envisaged. Some of the challenges discussed are the applicability to image live and/or large samples, the further enhancement of resolution, future developments of labels, and multi-spectral approaches.

  5. Perspectives in Super-resolved Fluorescence Microscopy: What comes next?

    Directory of Open Access Journals (Sweden)

    Christoph eCremer

    2016-04-01

    Full Text Available The Nobel Prize in Chemistry 2014 has been awarded to three scientists involved in the development of STED and PALM super-resolution fluorescence microscopy (SRM methods. They have proven that it is possible to overcome the hundred year old theoretical limit for the resolution potential of light microscopy (of about 200 nm for visible light, which for decades has precluded a direct glimpse of the molecular machinery of life. None of the present-day super-resolution techniques have invalidated the Abbe limit for light optical detection; however, they have found clever ways around it. In this report, we discuss some of the challenges still to be resolved before arising SRM approaches will be fit to bring about the revolution in Biology and Medicine envisaged. Some of the challenges discussed are the applicability to image live and/or large samples, the further enhancement of resolution, future developments of labels, and multi-spectral approaches.

  6. Intrinsic Depletion or Not

    DEFF Research Database (Denmark)

    Klösgen, Beate; Bruun, Sara; Hansen, Søren;

      The presence of a depletion layer of water along extended hydrophobic interfaces, and a possibly related formation of nanobubbles, is an ongoing discussion. The phenomenon was initially reported when we, years ago, chose thick films (~300-400Å) of polystyrene as cushions between a crystalline...... giving rise to depletion layers, and the mechanisms and border conditions that control their presence and extension require still clarification. Recently, careful systematic reflectivity experiments were re-done on the same system. No depletion layers were found, and it was conjectured that the whole...

  7. Gold triple-helix mid-infrared metamaterial by STED-inspired laser lithography.

    Science.gov (United States)

    Kaschke, Johannes; Wegener, Martin

    2015-09-01

    In analogy to wire-grid polarizers for linear polarization, metal-helix metamaterials can act as broadband circular polarizers. This concept has brought circular-polarization capabilities to mid-infrared and terahertz frequencies, which were previously difficult to access. Due to the lack of rotational symmetry, however, single-helix metamaterials exhibit unwanted circular-polarization conversions. Recent theoretical work showed that conversions can be fully eliminated by intertwining N=3 or 4 helices within each unit cell. While direct laser writing in positive-tone photo-resist yielded good results for single-helix metamaterials operating at mid-infrared frequencies, the axial resolution is insufficient for N-helix metamaterials. Here, we use stimulated emission depletion-inspired three-dimensional laser lithography to fabricate such microstructures. We measure all entries of the Jones transmission and reflection matrices and show experimentally that polarization conversions are minimized, in good agreement with theory.

  8. Addressing Ozone Layer Depletion

    Science.gov (United States)

    Access information on EPA's efforts to address ozone layer depletion through regulations, collaborations with stakeholders, international treaties, partnerships with the private sector, and enforcement actions under Title VI of the Clean Air Act.

  9. Intrinsic Depletion or Not

    DEFF Research Database (Denmark)

    Klösgen, Beate; Bruun, Sara; Hansen, Søren;

    with an AFM (2).    The intuitive explanation for the depletion based on "hydrophobic mismatch" between the obviously hydrophilic bulk phase of water next to the hydrophobic polymer. It would thus be an intrinsic property of all interfaces between non-matching materials. The detailed physical interaction path......  The presence of a depletion layer of water along extended hydrophobic interfaces, and a possibly related formation of nanobubbles, is an ongoing discussion. The phenomenon was initially reported when we, years ago, chose thick films (~300-400Å) of polystyrene as cushions between a crystalline...

  10. Shear-affected depletion interaction

    NARCIS (Netherlands)

    July, C.; Kleshchanok, D.; Lang, P.R.

    2012-01-01

    We investigate the influence of flow fields on the strength of the depletion interaction caused by disc-shaped depletants. At low mass concentration of discs, it is possible to continuously decrease the depth of the depletion potential by increasing the applied shear rate until the depletion force i

  11. 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)

  12. 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)

  13. Cortical actin networks induce spatio-temporal confinement of phospholipids in the plasma membrane - a minimally invasive investigation by STED-FCS

    Science.gov (United States)

    Andrade, Débora M.; Clausen, Mathias P.; Keller, Jan; Mueller, Veronika; Wu, Congying; Bear, James E.; Hell, Stefan W.; Lagerholm, B. Christoffer; Eggeling, Christian

    2015-06-01

    Important discoveries in the last decades have changed our view of the plasma membrane organisation. Specifically, the cortical cytoskeleton has emerged as a key modulator of the lateral diffusion of membrane proteins. Cytoskeleton-dependent compartmentalised lipid diffusion has been proposed, but this concept remains controversial because this phenomenon has thus far only been observed with artefact-prone probes in combination with a single technique: single particle tracking. In this paper, we report the first direct observation of compartmentalised phospholipid diffusion in the plasma membrane of living cells using a minimally invasive, fluorescent dye labelled lipid analogue. These observations were made using optical STED nanoscopy in combination with fluorescence correlation spectroscopy (STED-FCS), a technique which allows the study of membrane dynamics on a sub-millisecond time-scale and with a spatial resolution of down to 40 nm. Specifically, we find that compartmentalised phospholipid diffusion depends on the cortical actin cytoskeleton, and that this constrained diffusion is directly dependent on the F-actin branching nucleator Arp2/3. These findings provide solid evidence that the Arp2/3-dependent cortical actin cytoskeleton plays a pivotal role in the dynamic organisation of the plasma membrane, potentially regulating fundamental cellular processes.

  14. Depletion of intense fields

    CERN Document Server

    Seipt, D; Marklund, M; Bulanov, S S

    2016-01-01

    The interaction of charged particles and photons with intense electromagnetic fields gives rise to multi-photon Compton and Breit-Wheeler processes. These are usually described in the framework of the external field approximation, where the electromagnetic field is assumed to have infinite energy. However, the multi-photon nature of these processes implies the absorption of a significant number of photons, which scales as the external field amplitude cubed. As a result, the interaction of a highly charged electron bunch with an intense laser pulse can lead to significant depletion of the laser pulse energy, thus rendering the external field approximation invalid. We provide relevant estimates for this depletion and find it to become important in the interaction between fields of amplitude $a_0 \\sim 10^3$ and electron bunches with charges of the order of nC.

  15. Learning about ozone depletion

    Energy Technology Data Exchange (ETDEWEB)

    Crutzen, J. P. [Department of Atmospheric Chemistry, Max Planck Institute for Chemistry, Mainz, Germany; Oppenheimer M. [Woodrow Wilson School of Public and International Affairs, Department of Geosciences, Princeton University, Princeton, NJ (United States)

    2008-07-15

    Stratospheric ozone depletion has been much studied as a case history in the interaction between environmental science and environmental policy. The positive influence of science on policy is often underscored, but here we review the photochemistry of ozone in order to illustrate how scientific learning has the potential to mislead policy makers. The latter may occur particularly in circumstances where limited observations are combined with simplified models of a complex system, such as may generally occur in the global change arena. Even for the well-studied case of ozone depletion, further research is needed on the dynamics of scientific learning, particularly the scientific assessment process, and how assessments influence the development of public policy.

  16. Depletion of Intense Fields

    Science.gov (United States)

    Seipt, D.; Heinzl, T.; Marklund, M.; Bulanov, S. S.

    2017-04-01

    The interaction of charged particles and photons with intense electromagnetic fields gives rise to multiphoton Compton and Breit-Wheeler processes. These are usually described in the framework of the external field approximation, where the electromagnetic field is assumed to have infinite energy. However, the multiphoton nature of these processes implies the absorption of a significant number of photons, which scales as the external field amplitude cubed. As a result, the interaction of a highly charged electron bunch with an intense laser pulse can lead to significant depletion of the laser pulse energy, thus rendering the external field approximation invalid. We provide relevant estimates for this depletion and find it to become important in the interaction between fields of amplitude a0˜1 03 and electron bunches with charges of the order of 10 nC.

  17. Ozone-depleting Substances (ODS)

    Data.gov (United States)

    U.S. Environmental Protection Agency — This site includes all of the ozone-depleting substances (ODS) recognized by the Montreal Protocol. The data include ozone depletion potentials (ODP), global warming...

  18. Analytical Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    2006-06-01

    In the Analytical Microscopy group, within the National Center for Photovoltaic's Measurements and Characterization Division, we combine two complementary areas of analytical microscopy--electron microscopy and proximal-probe techniques--and use a variety of state-of-the-art imaging and analytical tools. We also design and build custom instrumentation and develop novel techniques that provide unique capabilities for studying materials and devices. In our work, we collaborate with you to solve materials- and device-related R&D problems. This sheet summarizes the uses and features of four major tools: transmission electron microscopy, scanning electron microscopy, the dual-beam focused-ion-beam workstation, and scanning probe microscopy.

  19. Et ganske konkret sted

    DEFF Research Database (Denmark)

    Wiesner, Thomas

    2008-01-01

    Kort beskrivelse af projektet til Liechtensteins nye forum og parlament i Vaduz; Indvieged i februar 2008, tegnet af arkitekt Hansjörg Göritz efter masterplan af Luigi Snozzi. Tekst: Thomas Wiesner. Fotos: Jürg Zürcher, Erik Kjær download af tidskrift: http://server02.dotminded.com/dotminded/data......Kort beskrivelse af projektet til Liechtensteins nye forum og parlament i Vaduz; Indvieged i februar 2008, tegnet af arkitekt Hansjörg Göritz efter masterplan af Luigi Snozzi. Tekst: Thomas Wiesner. Fotos: Jürg Zürcher, Erik Kjær download af tidskrift: http://server02.dotminded...

  20. Ozone Depletion by Hydrofluorocarbons

    Science.gov (United States)

    Hurwitz, M.; Fleming, E. L.; Newman, P. A.; Li, F.; Mlawer, E. J.; Cady-Pereira, K. E.; Bailey, R.

    2015-12-01

    Hydrofluorocarbons (HFCs) are second-generation replacements for the chlorofluorocarbons (CFCs), halons and other substances that caused the 'ozone hole'. Atmospheric concentrations of HFCs are projected to increase dramatically in the coming decades. Coupled chemistry-climate simulations forced by these projections show that HFCs will impact the global atmosphere in 2050. As strong radiative forcers, HFCs modulate atmospheric temperature, thereby changing ozone-destroying catalytic cycles and enhancing the stratospheric circulation. These changes lead to a weak depletion of stratospheric ozone. Sensitivity simulations with the NASA Goddard Space Flight Center (GSFC) 2D model show that HFC-125 is the most important contributor to atmospheric change in 2050, as compared with HFC-23, HFC-32, HFC-134a and HFC-143a. Incorporating the interactions between chemistry, radiation and dynamics, for a likely 2050 climate, ozone depletion potentials (ODPs) for HFCs range from 4.3x10-4 to 3.5x10-2; previously HFCs were assumed to have negligible ODPs since these species lack chlorine or bromine atoms. The ozone impacts of HFCs are further investigated with the Goddard Earth Observing System Chemistry-Climate Model (GEOSCCM). The GEOSCCM is a three-dimensional, fully coupled ocean-atmosphere model with interactive stratospheric chemistry. Sensitivity simulations in which CO2, CFC-11 and HCFC-22 are enhanced individually are used as proxies for the atmospheric response to the HFC concentrations expected by the mid-21st century. Sensitivity simulations provide quantitative estimates of the impacts of these greenhouse gases on global total ozone, and can be used to assess their effects on the recovery of Antarctic ozone.

  1. Depleted zinc: Properties, application, production.

    Science.gov (United States)

    Borisevich, V D; Pavlov, A V; Okhotina, I A

    2009-01-01

    The addition of ZnO, depleted in the Zn-64 isotope, to the water of boiling water nuclear reactors lessens the accumulation of Co-60 on the reactor interior surfaces, reduces radioactive wastes and increases the reactor service-life because of the inhibitory action of zinc on inter-granular stress corrosion cracking. To the same effect depleted zinc in the form of acetate dihydrate is used in pressurized water reactors. Gas centrifuge isotope separation method is applied for production of depleted zinc on the industrial scale. More than 20 years of depleted zinc application history demonstrates its benefits for reduction of NPP personnel radiation exposure and combating construction materials corrosion.

  2. Ego depletion impairs implicit learning.

    Science.gov (United States)

    Thompson, Kelsey R; Sanchez, Daniel J; Wesley, Abigail H; Reber, Paul J

    2014-01-01

    Implicit skill learning occurs incidentally and without conscious awareness of what is learned. However, the rate and effectiveness of learning may still be affected by decreased availability of central processing resources. Dual-task experiments have generally found impairments in implicit learning, however, these studies have also shown that certain characteristics of the secondary task (e.g., timing) can complicate the interpretation of these results. To avoid this problem, the current experiments used a novel method to impose resource constraints prior to engaging in skill learning. Ego depletion theory states that humans possess a limited store of cognitive resources that, when depleted, results in deficits in self-regulation and cognitive control. In a first experiment, we used a standard ego depletion manipulation prior to performance of the Serial Interception Sequence Learning (SISL) task. Depleted participants exhibited poorer test performance than did non-depleted controls, indicating that reducing available executive resources may adversely affect implicit sequence learning, expression of sequence knowledge, or both. In a second experiment, depletion was administered either prior to or after training. Participants who reported higher levels of depletion before or after training again showed less sequence-specific knowledge on the post-training assessment. However, the results did not allow for clear separation of ego depletion effects on learning versus subsequent sequence-specific performance. These results indicate that performance on an implicitly learned sequence can be impaired by a reduction in executive resources, in spite of learning taking place outside of awareness and without conscious intent.

  3. Depletable resources and the economy.

    NARCIS (Netherlands)

    Heijman, W.J.M.

    1991-01-01

    The subject of this thesis is the depletion of scarce resources. The main question to be answered is how to avoid future resource crises. After dealing with the complex relation between nature and economics, three important concepts in relation with resource depletion are discussed: steady state, ti

  4. Super-Resolution Scanning Laser Microscopy Based on Virtually Structured Detection

    OpenAIRE

    Zhi, Yanan; Wang, Benquan; Yao, Xincheng

    2015-01-01

    Light microscopy plays a key role in biological studies and medical diagnosis. The spatial resolution of conventional optical microscopes is limited to approximately half the wavelength of the illumination light as a result of the diffraction limit. Several approaches—including confocal microscopy, stimulated emission depletion microscopy, stochastic optical reconstruction microscopy, photoactivated localization microscopy, and structured illumination microscopy—have been established to achie...

  5. Testing fully depleted CCD

    Science.gov (United States)

    Casas, Ricard; Cardiel-Sas, Laia; Castander, Francisco J.; Jiménez, Jorge; de Vicente, Juan

    2014-08-01

    The focal plane of the PAU camera is composed of eighteen 2K x 4K CCDs. These devices, plus four spares, were provided by the Japanese company Hamamatsu Photonics K.K. with type no. S10892-04(X). These detectors are 200 μm thick fully depleted and back illuminated with an n-type silicon base. They have been built with a specific coating to be sensitive in the range from 300 to 1,100 nm. Their square pixel size is 15 μm. The read-out system consists of a Monsoon controller (NOAO) and the panVIEW software package. The deafualt CCD read-out speed is 133 kpixel/s. This is the value used in the calibration process. Before installing these devices in the camera focal plane, they were characterized using the facilities of the ICE (CSIC- IEEC) and IFAE in the UAB Campus in Bellaterra (Barcelona, Catalonia, Spain). The basic tests performed for all CCDs were to obtain the photon transfer curve (PTC), the charge transfer efficiency (CTE) using X-rays and the EPER method, linearity, read-out noise, dark current, persistence, cosmetics and quantum efficiency. The X-rays images were also used for the analysis of the charge diffusion for different substrate voltages (VSUB). Regarding the cosmetics, and in addition to white and dark pixels, some patterns were also found. The first one, which appears in all devices, is the presence of half circles in the external edges. The origin of this pattern can be related to the assembly process. A second one appears in the dark images, and shows bright arcs connecting corners along the vertical axis of the CCD. This feature appears in all CCDs exactly in the same position so our guess is that the pattern is due to electrical fields. Finally, and just in two devices, there is a spot with wavelength dependence whose origin could be the result of a defectous coating process.

  6. Introduction to Theories of Several Super-resolution Fluorescence Microscopy Methods and Recent Advance in The Field%几种超分辨率荧光显微技术的原理和近期进展

    Institute of Scientific and Technical Information of China (English)

    吕志坚; 陆敬泽; 吴雅琼; 陈良怡

    2009-01-01

    在生命科学领域,人们常常需要在细胞内精确定位特定的蛋白质以研究其位置与功能的关系.多年来,宽场/共聚焦荧光显微镜的分辨率受限于光的阿贝/瑞利极限,不能分辨出200 nm以下的结构.近年来,随着新的荧光探针和成像理论的出现,研究者开发了多种实现超出普通共聚焦显微镜分辨率的三维超分辨率成像方法.主要介绍这些方法的原理、近期进展和发展趋势.介绍了光源的点扩散函数(point spread function,PSF)的概念和传统分辨率的定义,阐述了提高xy平面分辨率的方法.通过介绍单分子荧光成像技术,引入了单分子成像定位精度的概念,介绍了基于单分子成像的超分辨率显微成像方法,包括光激活定位显微技术(photoactivated localization microscopy,PALM)和随机光学重构显微技术(stochastic optical reconstruction microscopy,STORM).介绍了两大类通过改造光源的点扩散函数米提高成像分辨率的方法,分别是受激发射损耗显微技术(stimulated emission depletion,STED)和饱和结构照明显微技术(saturated structure illumination microscopy,SSIM).比较了不同的z轴提取信息的方法,并阐述了这些方法与xy平面上的超分辨率显微成像技术相结合所得到的各种三维超分辨率显微成像技术的优劣.探讨了目前超分辨率显微成像的发展极限和方向.

  7. Confocal microscopy of colloids

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, V; Semwogerere, D; Weeks, Eric R [Department of Physics, Emory University, Atlanta, GA 30322 (United States)

    2007-03-21

    Colloids have increasingly been used to characterize or mimic many aspects of atomic and molecular systems. With confocal microscopy these colloidal particles can be tracked spatially in three dimensions with great precision over large time scales. This review discusses equilibrium phases such as crystals and liquids, and non-equilibrium phases such as glasses and gels. The phases that form depend strongly on the type of particle interaction that dominates. Hard-sphere-like colloids are the simplest, and interactions such as the attractive depletion force and electrostatic repulsion result in more non-trivial phases which can better model molecular materials. Furthermore, shearing or otherwise externally forcing these colloids while under microscopic observation helps connect the microscopic particle dynamics to the macroscopic flow behaviour. Finally, directions of future research in this field are discussed. (topical review)

  8. Endoscopic Microscopy

    Science.gov (United States)

    Sokolov, Konstantin; Sung, Kung-Bin; Collier, Tom; Clark, Anne; Arifler, Dizem; Lacy, Alicia; Descour, Michael; Richards-Kortum, Rebecca

    2002-01-01

    In vivo endoscopic optical microscopy provides a tool to assess tissue architecture and morphology with contrast and resolution similar to that provided by standard histopathology – without need for physical tissue removal. In this article, we focus on optical imaging technologies that have the potential to dramatically improve the detection, prevention, and therapy of epithelial cancers. Epithelial pre-cancers and cancers are associated with a variety of morphologic, architectural, and molecular changes, which currently can be assessed only through invasive, painful biopsy. Optical imaging is ideally suited to detecting cancer-related alterations because it can detect biochemical and morphologic alterations with sub-cellular resolution throughout the entire epithelial thickness. Optical techniques can be implemented non-invasively, in real time, and at low cost to survey the tissue surface at risk. Our manuscript focuses primarily on modalities that currently are the most developed: reflectance confocal microscopy (RCM) and optical coherence tomography (OCT). However, recent advances in fluorescence-based endoscopic microscopy also are reviewed briefly. We discuss the basic principles of these emerging technologies and their current and potential applications in early cancer detection. We also present research activities focused on development of exogenous contrast agents that can enhance the morphological features important for cancer detection and that have the potential to allow vital molecular imaging of cancer-related biomarkers. In conclusion, we discuss future improvements to the technology needed to develop robust clinical devices. PMID:14646041

  9. "When the going gets tough, who keeps going?" Depletion sensitivity moderates the ego-depletion effect.

    Science.gov (United States)

    Salmon, Stefanie J; Adriaanse, Marieke A; De Vet, Emely; Fennis, Bob M; De Ridder, Denise T D

    2014-01-01

    Self-control relies on a limited resource that can get depleted, a phenomenon that has been labeled ego-depletion. We argue that individuals may differ in their sensitivity to depleting tasks, and that consequently some people deplete their self-control resource at a faster rate than others. In three studies, we assessed individual differences in depletion sensitivity, and demonstrate that depletion sensitivity moderates ego-depletion effects. The Depletion Sensitivity Scale (DSS) was employed to assess depletion sensitivity. Study 1 employs the DSS to demonstrate that individual differences in sensitivity to ego-depletion exist. Study 2 shows moderate correlations of depletion sensitivity with related self-control concepts, indicating that these scales measure conceptually distinct constructs. Study 3 demonstrates that depletion sensitivity moderates the ego-depletion effect. Specifically, participants who are sensitive to depletion performed worse on a second self-control task, indicating a stronger ego-depletion effect, compared to participants less sensitive to depletion.

  10. Direct and precise length measurement of single, stretched DNA fragments by dynamic molecular combing and STED nanoscopy.

    Science.gov (United States)

    Kim, Namdoo; Kim, Hyung Jun; Kim, Younggyu; Min, Kyung Suk; Kim, Seong Keun

    2016-09-01

    A combination of DNA stretching method and super-resolution nanoscopy allows an accurate and precise measurement of the length of DNA fragments ranging widely in size from 117 to 23,130 bp. BstEII- and HindIII-treated λDNA fragments were stained with an intercalating dye and then linearly stretched on a coverslip by dynamic molecular combing. The image of individual DNA fragments was obtained by stimulated emission depletion nanoscopy. For DNA fragments longer than ∼1000 bp, the measured lengths of DNA fragments were consistently within ∼0.5 to 1.0 % of the reference values, raising the possibility of this method in a wide range of applications including facile detection for copy number variations and trinucleotide repeat disorder.

  11. Depleting depletion: Polymer swelling in poor solvent mixtures

    Science.gov (United States)

    Mukherji, Debashish; Marques, Carlos; Stuehn, Torsten; Kremer, Kurt

    A polymer collapses in a solvent when the solvent particles dislike monomers more than the repulsion between monomers. This leads to an effective attraction between monomers, also referred to as depletion induced attraction. This attraction is the key factor behind standard polymer collapse in poor solvents. Strikingly, even if a polymer exhibits poor solvent condition in two different solvents, it can also swell in mixtures of these two poor solvents. This collapse-swelling-collapse scenario is displayed by poly(methyl methacrylate) (PMMA) in aqueous alcohol. Using molecular dynamics simulations of a thermodynamically consistent generic model and theoretical arguments, we unveil the microscopic origin of this phenomenon. Our analysis suggests that a subtle interplay of the bulk solution properties and the local depletion forces reduces depletion effects, thus dictating polymer swelling in poor solvent mixtures.

  12. Rotational Mixing and Lithium Depletion

    CERN Document Server

    Pinsonneault, M H

    2010-01-01

    I review basic observational features in Population I stars which strongly implicate rotation as a mixing agent; these include dispersion at fixed temperature in coeval populations and main sequence lithium depletion for a range of masses at a rate which decays with time. New developments related to the possible suppression of mixing at late ages, close binary mergers and their lithium signature, and an alternate origin for dispersion in young cool stars tied to radius anomalies observed in active young stars are discussed. I highlight uncertainties in models of Population II lithium depletion and dispersion related to the treatment of angular momentum loss. Finally, the origins of rotation are tied to conditions in the pre-main sequence, and there is thus some evidence that enviroment and planet formation could impact stellar rotational properties. This may be related to recent observational evidence for cluster to cluster variations in lithium depletion and a connection between the presence of planets and s...

  13. Charge depletion in organic heterojunction

    Science.gov (United States)

    Ng, T. W.; Lo, M. F.; Lee, S. T.; Lee, C. S.

    2012-03-01

    Until now two types of organic-organic heterojunction (OHJ) have been observed in P-N junctions formed between undoped-organic semiconductors. Charge-transfers across OHJs are either negligible or showing electron transfer from P-type to N-type materials, leading to charges accumulation near the interface. Here, we observed that junction of 4,4',4''-tris(2-methylphenyl-phenylamino)triphenylamine (m-MTDATA)/bathocuproine (BCP) show the third-behavior. Electrons in BCP (N-type) transfer to m-MTDATA (P-type), leading to depletion of mobile majority carriers near the junction. While "depletion junctions" are typical in inorganic semiconductors, there are no reports in undoped-OHJ. Formation mechanism of depletion OHJs and fundamental differences between inorganic and organic HJs are discussed.

  14. Impact of mineral resource depletion

    CSIR Research Space (South Africa)

    Brent, AC

    2006-09-01

    Full Text Available In a letter to the editor, the authors comment on BA Steen's article on "Abiotic Resource Depletion: different perceptions of the problem with mineral deposits" published in the special issue of the International Journal of Life Cycle Assessment...

  15. Global depletion of groundwater resources

    NARCIS (Netherlands)

    Wada, Y.; Beek, L.P.H. van; van Kempen, C.M.; Reckman, J.W.T.M.; Vasak, S.; Bierkens, M.F.P.

    2010-01-01

    In regions with frequent water stress and large aquifer systems groundwater is often used as an additional water source. If groundwater abstraction exceeds the natural groundwater recharge for extensive areas and long times, overexploitation or persistent groundwater depletion occurs. Here we provid

  16. Method for enhancing stability in multi-beam microscopy

    Science.gov (United States)

    Huang, Yujia; Wang, Yifan; Kuang, Cuifang; Liu, Xu

    2016-10-01

    A method based on close loop control of four degrees of freedom (4DF) is proposed to enhance angular and translational stability of beams in multi-beam microscopy including STED, RESOLFT and CARS, etc. Deviations of multi-beams can be measured and corrected by our module, which is composed of four degrees of freedom position sensitive detectors (4DF PSD) and two actuator mirrors (AM) with motor and piezo servos. An output crosslink matrix obtained by a self-learning process is used to control four actuators to compensate for 4DF independently in beam deviations. We realize a standard deviation within about 2 µm at the entrance pupil plane (a spatial optical path of 180 cm for the whole system) using a compact stabilization system, which is equivalent to around 3 nm at the sample plane under the 100×  objective lens with a focal length of 2 mm, corresponding to an improvement of stability by an order of magnitude. Our method can react fast in real time and compensate for large disturbances caused by air agitation or temperature variation.

  17. Ozone Depletion from Nearby Supernovae

    CERN Document Server

    Gehrels, N; Jackman, C H; Cannizzo, J K; Mattson, B J; Chen, W; Gehrels, Neil; Laird, Claude M.; Jackman, Charles H.; Cannizzo, John K.; Mattson, Barbara J.; Chen, Wan

    2003-01-01

    Estimates made in the 1970's indicated that a supernova occurring within tens of parsecs of Earth could have significant effects on the ozone layer. Since that time, improved tools for detailed modeling of atmospheric chemistry have been developed to calculate ozone depletion, and advances have been made in theoretical modeling of supernovae and of the resultant gamma-ray spectra. In addition, one now has better knowledge of the occurrence rate of supernovae in the galaxy, and of the spatial distribution of progenitors to core-collapse supernovae. We report here the results of two-dimensional atmospheric model calculations that take as input the spectral energy distribution of a supernova, adopting various distances from Earth and various latitude impact angles. In separate simulations we calculate the ozone depletion due to both gamma-rays and cosmic rays. We find that for the combined ozone depletion roughly to double the ``biologically active'' UV flux received at the surface of the Earth, the supernova mu...

  18. Ozone Depletion from Nearby Supernovae

    Science.gov (United States)

    Gehrels, Neil; Laird, Claude M.; Jackman, Charles H.; Cannizzo, John K.; Mattson, Barbara J.; Chen, Wan; Bhartia, P. K. (Technical Monitor)

    2002-01-01

    Estimates made in the 1970's indicated that a supernova occurring within tens of parsecs of Earth could have significant effects on the ozone layer. Since that time improved tools for detailed modeling of atmospheric chemistry have been developed to calculate ozone depletion, and advances have been made also in theoretical modeling of supernovae and of the resultant gamma ray spectra. In addition, one now has better knowledge of the occurrence rate of supernovae in the galaxy, and of the spatial distribution of progenitors to core-collapse supernovae. We report here the results of two-dimensional atmospheric model calculations that take as input the spectral energy distribution of a supernova, adopting various distances from Earth and various latitude impact angles. In separate simulations we calculate the ozone depletion due to both gamma rays and cosmic rays. We find that for the combined ozone depletion from these effects roughly to double the 'biologically active' UV flux received at the surface of the Earth, the supernova must occur at approximately or less than 8 parsecs.

  19. Ozone depletion, paradigms, and politics

    Energy Technology Data Exchange (ETDEWEB)

    Iman, R.L.

    1993-10-01

    The destruction of the Earth`s protective ozone layer is a prime environmental concern. Industry has responded to this environmental problem by: implementing conservation techniques to reduce the emission of ozone-depleting chemicals (ODCs); using alternative cleaning solvents that have lower ozone depletion potentials (ODPs); developing new, non-ozone-depleting solvents, such as terpenes; and developing low-residue soldering processes. This paper presents an overview of a joint testing program at Sandia and Motorola to evaluate a low-residue (no-clean) soldering process for printed wiring boards (PWBs). Such processes are in widespread use in commercial applications because they eliminate the cleaning operation. The goal of this testing program was to develop a data base that could be used to support changes in the mil-specs. In addition, a joint task force involving industry and the military has been formed to conduct a follow-up evaluation of low-residue processes that encompass the concerns of the tri-services. The goal of the task force is to gain final approval of the low-residue technology for use in military applications.

  20. Protection of ATP-Depleted Cells by Impermeant Strychnine Derivatives

    Science.gov (United States)

    Dong, Zheng; Venkatachalam, Manjeri A.; Weinberg, Joel M.; Saikumar, Pothana; Patel, Yogendra

    2001-01-01

    Glycine and structurally related amino acids with activities at chloride channel receptors in the central nervous system also have robust protective effects against cell injury by ATP depletion. The glycine receptor antagonist strychnine shares this protective activity. An essential step toward identification of the molecular targets for these compounds is to determine whether they protect cells through interactions with intracellular targets or with molecules on the outer surface of plasma membranes. Here we report cytoprotection by a cell-impermeant derivative of strychnine. A strychnine-fluorescein conjugate (SF) was synthesized, and impermeability of plasma membranes to this compound was verified by fluorescence confocal microscopy. In an injury model of Madin-Darby canine kidney cells, ATP depletion led to lactate dehydrogenase release. SF prevented lactate dehydrogenase leakage without ameliorating ATP depletion. This was accompanied by preservation of cellular ultrastructure and exclusion of vital dyes. SF protection was also shown for ATP-depleted rat hepatocytes. On the other hand, when a key structural motif in the active site of strychnine was chemically blocked, the SF lost its protective effect, establishing strychnine-related specificity for SF protection. Cytoprotective effects of the cell-impermeant strychnine derivative provide compelling evidence suggesting that molecular targets on the outer surface of plasma membranes may mediate cytoprotection by strychnine and glycine. PMID:11238050

  1. DIRECT MEASUREMENT OF WEAK DEPLETION FORCE BETWEEN TWO SURFACES*

    Institute of Scientific and Technical Information of China (English)

    Xiang-jun Gong; Xiao-chen Xing; Xiao-ling Wei; To Ngai

    2011-01-01

    In a mixture of colloidal particles and polymer molecules, the particles may experience an attractive “depletion force” if the size of the polymer molecule is larger than the interparticle separation. This is because individual polymer molecules experience less conformational entropy if they stay between the particles than they escape the inter-particle space,which results in an osmotic pressure imbalance inside and outside the gap and leads to interparticle attraction. This depletion force has been the subject of several studies since the 1980s, but the direct measurement of this force is still experimentally challenging as it requires the detection of energy variations of the order of kBT and beyond. We present here our results for applying total internal reflection microscopy (TIRM) to directly measure the interaction between a free-moving particle and a flat surface in solutions consisting of small water-soluble organic molecules or polymeric surfactants. Our results indicate that stable nanobubbles (ca. 150 nm) exist free in the above aqueous solutions. More importantly, the existence of such nanobubbles induces an attraction between the spherical particle and flat surface. Using TIRM, we are able to directly measure such weak interaction with a range up to 100 nm. Furthermore, we demonstrate that by employing thermo-sensitive microgel particles as a depleting agent, we are able to quantitatively measure and reversibly control kBT-scale depletion attraction as function of solution pH.

  2. Local depletion of glycogen with supra-maximal exercise in human skeletal muscle fibres

    DEFF Research Database (Denmark)

    Gejl, K D; Ørtenblad, N; Andersson, E

    2017-01-01

    four ∼4-minute supra-maximal sprint time trials (STT 1-4) with 45 min recovery. The sub-cellular glycogen volumes in m. triceps brachii were quantified from electron microscopy images before and after both STT 1 and STT 4. During STT 1, the depletion of intramyofibrillar glycogen was higher in type I...... glycogen volume was significantly reduced during STT 4, in both fibre types (main effect: -31% [-50:-11%], P = 0.002). Furthermore, for each of the sub-cellular compartments, the depletion of glycogen during STT 1 was associated with the volumes of glycogen before STT 1. In conclusion, the depletion...

  3. The Case of Ozone Depletion

    Science.gov (United States)

    Lambright, W. Henry

    2005-01-01

    While the National Aeronautics and Space Administration (NASA) is widely perceived as a space agency, since its inception NASA has had a mission dedicated to the home planet. Initially, this mission involved using space to better observe and predict weather and to enable worldwide communication. Meteorological and communication satellites showed the value of space for earthly endeavors in the 1960s. In 1972, NASA launched Landsat, and the era of earth-resource monitoring began. At the same time, in the late 1960s and early 1970s, the environmental movement swept throughout the United States and most industrialized countries. The first Earth Day event took place in 1970, and the government generally began to pay much more attention to issues of environmental quality. Mitigating pollution became an overriding objective for many agencies. NASA's existing mission to observe planet Earth was augmented in these years and directed more toward environmental quality. In the 1980s, NASA sought to plan and establish a new environmental effort that eventuated in the 1990s with the Earth Observing System (EOS). The Agency was able to make its initial mark via atmospheric monitoring, specifically ozone depletion. An important policy stimulus in many respects, ozone depletion spawned the Montreal Protocol of 1987 (the most significant international environmental treaty then in existence). It also was an issue critical to NASA's history that served as a bridge linking NASA's weather and land-resource satellites to NASA s concern for the global changes affecting the home planet. Significantly, as a global environmental problem, ozone depletion underscored the importance of NASA's ability to observe Earth from space. Moreover, the NASA management team's ability to apply large-scale research efforts and mobilize the talents of other agencies and the private sector illuminated its role as a lead agency capable of crossing organizational boundaries as well as the science-policy divide.

  4. VirusMapper: open-source nanoscale mapping of viral architecture through super-resolution microscopy

    Science.gov (United States)

    Gray, Robert D. M.; Beerli, Corina; Pereira, Pedro Matos; Scherer, Kathrin Maria; Samolej, Jerzy; Bleck, Christopher Karl Ernst; Mercer, Jason; Henriques, Ricardo

    2016-01-01

    The nanoscale molecular assembly of mammalian viruses during their infectious life cycle remains poorly understood. Their small dimensions, generally bellow the 300nm diffraction limit of light microscopes, has limited most imaging studies to electron microscopy. The recent development of super-resolution (SR) light microscopy now allows the visualisation of viral structures at resolutions of tens of nanometers. In addition, these techniques provide the added benefit of molecular specific labelling and the capacity to investigate viral structural dynamics using live-cell microscopy. However, there is a lack of robust analytical tools that allow for precise mapping of viral structure within the setting of infection. Here we present an open-source analytical framework that combines super-resolution imaging and naïve single-particle analysis to generate unbiased molecular models. This tool, VirusMapper, is a high-throughput, user-friendly, ImageJ-based software package allowing for automatic statistical mapping of conserved multi-molecular structures, such as viral substructures or intact viruses. We demonstrate the usability of VirusMapper by applying it to SIM and STED images of vaccinia virus in isolation and when engaged with host cells. VirusMapper allows for the generation of accurate, high-content, molecular specific virion models and detection of nanoscale changes in viral architecture. PMID:27374400

  5. Action orientation overcomes the ego depletion effect.

    Science.gov (United States)

    Dang, Junhua; Xiao, Shanshan; Shi, Yucai; Mao, Lihua

    2015-04-01

    It has been consistently demonstrated that initial exertion of self-control had negative influence on people's performance on subsequent self-control tasks. This phenomenon is referred to as the ego depletion effect. Based on action control theory, the current research investigated whether the ego depletion effect could be moderated by individuals' action versus state orientation. Our results showed that only state-oriented individuals exhibited ego depletion. For individuals with action orientation, however, their performance was not influenced by initial exertion of self-control. The beneficial effect of action orientation against ego depletion in our experiment results from its facilitation for adapting to the depleting task.

  6. "When the going gets tough, who keeps going?" Depletion sensitivity moderates the ego-depletion effect

    NARCIS (Netherlands)

    Salmon, Stefanie J.; Adriaanse, Marieke A.; De Vet, Emely; Fennis, Bob M.; De Ridder, Denise T D

    2014-01-01

    Self-control relies on a limited resource that can get depleted, a phenomenon that has been labeled ego-depletion. We argue that individuals may differ in their sensitivity to depleting tasks, and that consequently some people deplete their self-control resource at a faster rate than others. In thre

  7. "When the going gets tough, who keeps going?" : Depletion sensitivity moderates the ego-depletion effect

    NARCIS (Netherlands)

    Salmon, Stefanie J.; Adriaanse, Marieke A.; De Vet, Emely; Fennis, Bob M.; De Ridder, Denise T. D.

    2014-01-01

    Self-control relies on a limited resource that can get depleted, a phenomenon that has been labeled ego-depletion. We argue that individuals may differ in their sensitivity to depleting tasks, and that consequently some people deplete their self-control resource at a faster rate than others. In thre

  8. "When the going gets tough, who keeps going?" : Depletion sensitivity moderates the ego-depletion effect

    NARCIS (Netherlands)

    Salmon, Stefanie J.; Adriaanse, Marieke A.; De Vet, Emely; Fennis, Bob M.; De Ridder, Denise T. D.

    2014-01-01

    Self-control relies on a limited resource that can get depleted, a phenomenon that has been labeled ego-depletion. We argue that individuals may differ in their sensitivity to depleting tasks, and that consequently some people deplete their self-control resource at a faster rate than others. In thre

  9. Physics of Fully Depleted CCDs

    CERN Document Server

    Holland, S E; Kolbe, W F; Lee, J S

    2014-01-01

    In this work we present simple, physics-based models for two effects that have been noted in the fully depleted CCDs that are presently used in the Dark Energy Survey Camera. The first effect is the observation that the point-spread function increases slightly with the signal level. This is explained by considering the effect on charge-carrier diffusion due to the reduction in the magnitude of the channel potential as collected signal charge acts to partially neutralize the fixed charge in the depleted channel. The resulting reduced voltage drop across the carrier drift region decreases the vertical electric field and increases the carrier transit time. The second effect is the observation of low-level, concentric ring patterns seen in uniformly illuminated images. This effect is shown to be most likely due to lateral deflection of charge during the transit of the photogenerated carriers to the potential wells as a result of lateral electric fields. The lateral fields are a result of space charge in the fully...

  10. The 1988 Antarctic ozone depletion - Comparison with previous year depletions

    Science.gov (United States)

    Schoeberl, Mark R.; Stolarski, Richard S.; Krueger, Arlin J.

    1989-01-01

    The 1988 spring Antarctic ozone depletion was observed by TOMS to be substantially smaller than in recent years. The minimum polar total ozone values declined only 15 percent during September 1988, compared to nearly 50 percent during September 1987. At southern midlatitudes, exceptionally high total ozone values were recorded beginning in July 1988. The total integrated southern hemispheric ozone increased rapidly during the Austral spring, approaching 1980 levels during October. The high midlatitude total ozone values were associated with a substantial increase in eddy activity as indicated by the standard deviation in total ozone in the zonal band 30-60 deg S. Mechanisms through which the increased midlatitude eddy activity could disrupt the formation of the Antarctic ozone hole are briefly discussed.

  11. Depleted uranium disposal options evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Hertzler, T.J.; Nishimoto, D.D.; Otis, M.D. [Science Applications International Corp., Idaho Falls, ID (United States). Waste Management Technology Div.

    1994-05-01

    The Department of Energy (DOE), Office of Environmental Restoration and Waste Management, has chartered a study to evaluate alternative management strategies for depleted uranium (DU) currently stored throughout the DOE complex. Historically, DU has been maintained as a strategic resource because of uses for DU metal and potential uses for further enrichment or for uranium oxide as breeder reactor blanket fuel. This study has focused on evaluating the disposal options for DU if it were considered a waste. This report is in no way declaring these DU reserves a ``waste,`` but is intended to provide baseline data for comparison with other management options for use of DU. To PICS considered in this report include: Retrievable disposal; permanent disposal; health hazards; radiation toxicity and chemical toxicity.

  12. Ego depletion increases risk-taking.

    Science.gov (United States)

    Fischer, Peter; Kastenmüller, Andreas; Asal, Kathrin

    2012-01-01

    We investigated how the availability of self-control resources affects risk-taking inclinations and behaviors. We proposed that risk-taking often occurs from suboptimal decision processes and heuristic information processing (e.g., when a smoker suppresses or neglects information about the health risks of smoking). Research revealed that depleted self-regulation resources are associated with reduced intellectual performance and reduced abilities to regulate spontaneous and automatic responses (e.g., control aggressive responses in the face of frustration). The present studies transferred these ideas to the area of risk-taking. We propose that risk-taking is increased when individuals find themselves in a state of reduced cognitive self-control resources (ego-depletion). Four studies supported these ideas. In Study 1, ego-depleted participants reported higher levels of sensation seeking than non-depleted participants. In Study 2, ego-depleted participants showed higher levels of risk-tolerance in critical road traffic situations than non-depleted participants. In Study 3, we ruled out two alternative explanations for these results: neither cognitive load nor feelings of anger mediated the effect of ego-depletion on risk-taking. Finally, Study 4 clarified the underlying psychological process: ego-depleted participants feel more cognitively exhausted than non-depleted participants and thus are more willing to take risks. Discussion focuses on the theoretical and practical implications of these findings.

  13. Investigation of intranodal depletion effects

    Energy Technology Data Exchange (ETDEWEB)

    Forslund, P. E-mail: petri.forslund@se.abb.com; Mueller, E.; Lindahl, S

    2001-02-01

    The modeling of depletion induced intranodal effects on important neutron physical parameters in nodal diffusion theory is addressed. Consideration is given to two situations where these aspects are of particular interest, namely, in mixed oxide cores where strong interaction between uranium and plutonium mixed oxide assemblies occur, and in boiling water reactor cores where significant control rod history effects are encountered. A model based on a low order polynomial representation of intranodal cross-section spatial behaviour is considered. Two approaches for determining the constraints for the polynomial fitting procedure are applied. The first one is a conventional method employing intranodal exposure values, whereas the second model combines intranodal exposure and isotopic inventory information. Numerical studies are performed in order to evaluate the relative merits of the different models. It is demonstrated that pin power predictions are significantly influenced by intranodal effects. It is also found that the combined use of intranodal isotopic inventory and exposure distributions for estimating intranodal cross-section behaviour significantly improves the accuracy in pin powers over the more traditional approach of utilizing exposure distributions only.

  14. Depleted argon from underground sources

    Energy Technology Data Exchange (ETDEWEB)

    Back, H.O.; /Princeton U.; Alton, A.; /Augustana U. Coll.; Calaprice, F.; Galbiati, C.; Goretti, A.; /Princeton U.; Kendziora, C.; /Fermilab; Loer, B.; /Princeton U.; Montanari, D.; /Fermilab; Mosteiro, P.; /Princeton U.; Pordes, S.; /Fermilab

    2011-09-01

    Argon is a powerful scintillator and an excellent medium for detection of ionization. Its high discrimination power against minimum ionization tracks, in favor of selection of nuclear recoils, makes it an attractive medium for direct detection of WIMP dark matter. However, cosmogenic {sup 39}Ar contamination in atmospheric argon limits the size of liquid argon dark matter detectors due to pile-up. The cosmic ray shielding by the earth means that Argon from deep underground is depleted in {sup 39}Ar. In Cortez Colorado a CO{sub 2} well has been discovered to contain approximately 500ppm of argon as a contamination in the CO{sub 2}. In order to produce argon for dark matter detectors we first concentrate the argon locally to 3-5% in an Ar, N{sub 2}, and He mixture, from the CO{sub 2} through chromatographic gas separation. The N{sub 2} and He will be removed by continuous cryogenic distillation in the Cryogenic Distillation Column recently built at Fermilab. In this talk we will discuss the entire extraction and purification process; with emphasis on the recent commissioning and initial performance of the cryogenic distillation column purification.

  15. 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

  16. 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 sel

  17. Three-dimensional nanometre localization of nanoparticles to enhance super-resolution microscopy.

    Science.gov (United States)

    Bon, Pierre; Bourg, Nicolas; Lécart, Sandrine; Monneret, Serge; Fort, Emmanuel; Wenger, Jérôme; Lévêque-Fort, Sandrine

    2015-07-27

    Meeting the nanometre resolution promised by super-resolution microscopy techniques (pointillist: PALM, STORM, scanning: STED) requires stabilizing the sample drifts in real time during the whole acquisition process. Metal nanoparticles are excellent probes to track the lateral drifts as they provide crisp and photostable information. However, achieving nanometre axial super-localization is still a major challenge, as diffraction imposes large depths-of-fields. Here we demonstrate fast full three-dimensional nanometre super-localization of gold nanoparticles through simultaneous intensity and phase imaging with a wavefront-sensing camera based on quadriwave lateral shearing interferometry. We show how to combine the intensity and phase information to provide the key to the third axial dimension. Presently, we demonstrate even in the occurrence of large three-dimensional fluctuations of several microns, unprecedented sub-nanometre localization accuracies down to 0.7 nm in lateral and 2.7 nm in axial directions at 50 frames per second. We demonstrate that nanoscale stabilization greatly enhances the image quality and resolution in direct stochastic optical reconstruction microscopy imaging.

  18. Depletion sensitivity predicts unhealthy snack purchases

    NARCIS (Netherlands)

    Salmon, Stefanie J.; Adriaanse, Marieke A.; Fennis, Bob M.; Vet, De Emely; Ridder, De Denise T.D.

    2016-01-01

    The aim of the present research is to examine the relation between depletion sensitivity - a novel construct referring to the speed or ease by which one's self-control resources are drained - and snack purchase behavior. In addition, interactions between depletion sensitivity and the goal to lose

  19. Depletion sensitivity predicts unhealthy snack purchases

    NARCIS (Netherlands)

    Salmon, Stefanie J.; Adriaanse, Marieke A.|info:eu-repo/dai/nl/304823023; Fennis, Bob M.; De Vet, Emely; De Ridder, Denise T D

    2016-01-01

    The aim of the present research is to examine the relation between depletion sensitivity - a novel construct referring to the speed or ease by which one's self-control resources are drained - and snack purchase behavior. In addition, interactions between depletion sensitivity and the goal to lose

  20. The Chemistry and Toxicology of Depleted Uranium

    Directory of Open Access Journals (Sweden)

    Sidney A. Katz

    2014-03-01

    Full Text Available Natural uranium is comprised of three radioactive isotopes: 238U, 235U, and 234U. Depleted uranium (DU is a byproduct of the processes for the enrichment of the naturally occurring 235U isotope. The world wide stock pile contains some 1½ million tons of depleted uranium. Some of it has been used to dilute weapons grade uranium (~90% 235U down to reactor grade uranium (~5% 235U, and some of it has been used for heavy tank armor and for the fabrication of armor-piercing bullets and missiles. Such weapons were used by the military in the Persian Gulf, the Balkans and elsewhere. The testing of depleted uranium weapons and their use in combat has resulted in environmental contamination and human exposure. Although the chemical and the toxicological behaviors of depleted uranium are essentially the same as those of natural uranium, the respective chemical forms and isotopic compositions in which they usually occur are different. The chemical and radiological toxicity of depleted uranium can injure biological systems. Normal functioning of the kidney, liver, lung, and heart can be adversely affected by depleted uranium intoxication. The focus of this review is on the chemical and toxicological properties of depleted and natural uranium and some of the possible consequences from long term, low dose exposure to depleted uranium in the environment.

  1. High homocysteine induces betaine depletion.

    Science.gov (United States)

    Imbard, Apolline; Benoist, Jean-François; Esse, Ruben; Gupta, Sapna; Lebon, Sophie; de Vriese, An S; de Baulny, Helene Ogier; Kruger, Warren; Schiff, Manuel; Blom, Henk J

    2015-04-28

    Betaine is the substrate of the liver- and kidney-specific betaine-homocysteine (Hcy) methyltransferase (BHMT), an alternate pathway for Hcy remethylation. We hypothesized that BHMT is a major pathway for homocysteine removal in cases of hyperhomocysteinaemia (HHcy). Therefore, we measured betaine in plasma and tissues from patients and animal models of HHcy of genetic and acquired cause. Plasma was collected from patients presenting HHcy without any Hcy interfering treatment. Plasma and tissues were collected from rat models of HHcy induced by diet and from a mouse model of cystathionine β-synthase (CBS) deficiency. S-adenosyl-methionine (AdoMet), S-adenosyl-homocysteine (AdoHcy), methionine, betaine and dimethylglycine (DMG) were quantified by ESI-LC-MS/MS. mRNA expression was quantified using quantitative real-time (QRT)-PCR. For all patients with diverse causes of HHcy, plasma betaine concentrations were below the normal values of our laboratory. In the diet-induced HHcy rat model, betaine was decreased in all tissues analysed (liver, brain, heart). In the mouse CBS deficiency model, betaine was decreased in plasma, liver, heart and brain, but was conserved in kidney. Surprisingly, BHMT expression and activity was decreased in liver. However, in kidney, BHMT and SLC6A12 expression was increased in CBS-deficient mice. Chronic HHcy, irrespective of its cause, induces betaine depletion in plasma and tissues (liver, brain and heart), indicating a global decrease in the body betaine pool. In kidney, betaine concentrations were not affected, possibly due to overexpression of the betaine transporter SLC6A12 where betaine may be conserved because of its crucial role as an osmolyte.

  2. Specification for the VERA Depletion Benchmark Suite

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kang Seog [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-12-17

    CASL-X-2015-1014-000 iii Consortium for Advanced Simulation of LWRs EXECUTIVE SUMMARY The CASL neutronics simulator MPACT is under development for the neutronics and T-H coupled simulation for the pressurized water reactor. MPACT includes the ORIGEN-API and internal depletion module to perform depletion calculations based upon neutron-material reaction and radioactive decay. It is a challenge to validate the depletion capability because of the insufficient measured data. One of the detoured methods to validate it is to perform a code-to-code comparison for benchmark problems. In this study a depletion benchmark suite has been developed and a detailed guideline has been provided to obtain meaningful computational outcomes which can be used in the validation of the MPACT depletion capability.

  3. Membranes and Fluorescence microscopy

    DEFF Research Database (Denmark)

    Bagatolli, Luis

    2009-01-01

    be provided by microscopy-related techniques. In this chapter, I will attempt to summarize representative examples concerning how microscopy (which provides information on membrane lateral organization by direct visualization) and spectroscopy techniques (which provides information about molecular interaction...

  4. Possible ozone depletions following nuclear explosions

    Science.gov (United States)

    Whitten, R. C.; Borucki, W. J.; Turco, R. P.

    1975-01-01

    The degree of depletion of the ozone layer ensuing after delivery of strategic nuclear warheads (5000 and 10,000 Mton) due to production of nitrogen oxides is theoretically assessed. Strong depletions are calculated for 16-km and 26-km altitudes, peaking 1-2 months after detonation and lasting for three years, while a significant depletion at 36 km would peak after one year. Assuming the explosions occur between 30 and 70 deg N, these effects should be much more pronounced in this region than over the Northern Hemisphere as a whole. It is concluded that Hampson's concern on this matter (1974) is well-founded.-

  5. Where Do We Stand with Super-Resolution Optical Microscopy?

    Science.gov (United States)

    Nienhaus, Karin; Nienhaus, G Ulrich

    2016-01-29

    Super-resolution fluorescence microscopy has become an invaluable, powerful approach to study biomolecular dynamics and interactions via selective labeling and observation of specific molecules in living cells, tissues and even entire organisms. In this perspective, we present a brief overview of the main techniques and their application to cellular biophysics. We place special emphasis on super-resolution imaging via single-molecule localization microscopy and stimulated emission depletion/reversible saturable optical fluorescence transitions microscopy, and we also briefly address fluorescence fluctuation approaches, notably raster image correlation spectroscopy, as tools to record fast diffusion and transport.

  6. Polar stratospheric clouds and ozone depletion

    Science.gov (United States)

    Toon, Owen B.; Turco, Richard P.

    1991-01-01

    A review is presented of investigations into the correlation between the depletion of ozone and the formation of polar stratospheric clouds (PSCs). Satellite measurements from Nimbus 7 showed that over the years the depletion from austral spring to austral spring has generally worsened. Approximately 70 percent of the ozone above Antarctica, which equals about 3 percent of the earth's ozone, is lost during September and October. Various hypotheses for ozone depletion are discussed including the theory suggesting that chlorine compounds might be responsible for the ozone hole, whereby chlorine enters the atmosphere as a component of chlorofluorocarbons produced by humans. The three types of PSCs, nitric acid trihydrate, slowly cooling water-ice, and rapidly cooling water-ice clouds act as important components of the Antarctic ozone depletion. It is indicated that destruction of the ozone will be more severe each year for the next few decades, leading to a doubling in area of the Antarctic ozone hole.

  7. Depleted bulk heterojunction colloidal quantum dot photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Barkhouse, D.A.R. [Department of Electrical and Computer Engineering, University of Toronto, 10 King' s College Road, Toronto, Ontario M5S 3G4 (Canada); IBM Thomas J. Watson Research Center, Kitchawan Road, Yorktown Heights, NY, 10598 (United States); Debnath, Ratan; Kramer, Illan J.; Zhitomirsky, David; Levina, Larissa; Sargent, Edward H. [Department of Electrical and Computer Engineering, University of Toronto, 10 King' s College Road, Toronto, Ontario M5S 3G4 (Canada); Pattantyus-Abraham, Andras G. [Department of Electrical and Computer Engineering, University of Toronto, 10 King' s College Road, Toronto, Ontario M5S 3G4 (Canada); Quantum Solar Power Corporation, 1055 W. Hastings, Ste. 300, Vancouver, BC, V6E 2E9 (Canada); Etgar, Lioz; Graetzel, Michael [Laboratory for Photonics and Interfaces, Institute of Chemical Sciences and Engineering, School of Basic Sciences, Swiss Federal Institute of Technology, CH-1015 Lausanne (Switzerland)

    2011-07-26

    The first solution-processed depleted bulk heterojunction colloidal quantum dot solar cells are presented. The architecture allows for high absorption with full depletion, thereby breaking the photon absorption/carrier extraction compromise inherent in planar devices. A record power conversion of 5.5% under simulated AM 1.5 illumination conditions is reported. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Depleted Bulk Heterojunction Colloidal Quantum Dot Photovoltaics

    KAUST Repository

    Barkhouse, D. Aaron R.

    2011-05-26

    The first solution-processed depleted bulk heterojunction colloidal quantum dot solar cells are presented. The architecture allows for high absorption with full depletion, thereby breaking the photon absorption/carrier extraction compromise inherent in planar devices. A record power conversion of 5.5% under simulated AM 1.5 illumination conditions is reported. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Effects of Riverbed Conductance on Stream Depletion

    Science.gov (United States)

    Lackey, G.; Neupauer, R. M.; Pitlick, J.

    2012-12-01

    In the western United States and other regions of the world where growing population and changing climates are threatening water supplies, accurate modeling of potential human impacts on water resources is becoming more important. Stream depletion, the reduction of surface water flow due to the extraction of groundwater from a hydraulically connected aquifer, is one of the more direct ways that development can alter water availability, degrade water quality and endanger aquatic habitats. These factors have made the accurate modeling of stream depletion an important step in the process of installing groundwater wells in regions that are susceptible to this phenomenon. Proper estimation of stream depletion requires appropriate parameterization of aquifer and streambed hydraulic properties. Although many studies have conducted numerical investigations to determine stream depletion at specific sites, they typically do not measure streambed hydraulic conductivity (Kr), but rather assume a representative value. In this work, we establish a hypothetical model aquifer that is 2000 m by 1600 m and has a meandering stream running through its center. The Kr of the model stream is varied from 1.0x10-9 m s-1 to 1.0x10-2 m s-1 in order to determine the sensitivity of the stream depletion calculations to this parameter. It was found that when Kr is in the lower part of this range, slight changes in K¬r lead to significant impacts on the calculated stream depletion values. We vary Kr along the stream channel according to naturally occurring patterns and demonstrate that alterations of the parameter over a few orders of magnitude can affect the estimated stream depletion caused by a well at a specified location. The numerical simulations show that the mean value of Kr and its spatial variability along the channel should be realistic to develop an accurate model of stream depletion.

  10. A theoretical model of atmospheric ozone depletion

    Science.gov (United States)

    Midya, S. K.; Jana, P. K.; Lahiri, T.

    1994-01-01

    A critical study on different ozone depletion and formation processes has been made and following important results are obtained: (i) From analysis it is shown that O3 concentration will decrease very minutely with time for normal atmosphere when [O], [O2] and UV-radiation remain constant. (ii) An empirical equation is established theoretically between the variation of ozone concentration and time. (iii) Special ozone depletion processes are responsible for the dramatic decrease of O3-concentration at Antarctica.

  11. Anatomy of Depleted Interplanetary Coronal Mass Ejections

    Science.gov (United States)

    Kocher, M.; Lepri, S. T.; Landi, E.; Zhao, L.; Manchester, W. B., IV

    2017-01-01

    We report a subset of interplanetary coronal mass ejections (ICMEs) containing distinct periods of anomalous heavy-ion charge state composition and peculiar ion thermal properties measured by ACE/SWICS from 1998 to 2011. We label them “depleted ICMEs,” identified by the presence of intervals where C6+/C5+ and O7+/O6+ depart from the direct correlation expected after their freeze-in heights. These anomalous intervals within the depleted ICMEs are referred to as “Depletion Regions.” We find that a depleted ICME would be indistinguishable from all other ICMEs in the absence of the Depletion Region, which has the defining property of significantly low abundances of fully charged species of helium, carbon, oxygen, and nitrogen. Similar anomalies in the slow solar wind were discussed by Zhao et al. We explore two possibilities for the source of the Depletion Region associated with magnetic reconnection in the tail of a CME, using CME simulations of the evolution of two Earth-bound CMEs described by Manchester et al.

  12. 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)

  13. Quantification of depletion-induced adhesion of Red Blood Cells

    CERN Document Server

    Steffen, Patrick; Wagner, Christian

    2012-01-01

    Red blood cells (RBC) are known to form aggregates in the forms of rouleaux due to the presence of plasma proteins under physiological conditions. Rouleaux formation can be also induced in vitro by the addition of macromolecules to the RBC solution. Current data on the adhesion strength between red blood cells in their natural discocyte shapes mostly rely on indirect measurements like flow chamber experiments, but on the single cell level data is lacking. Here we present measurements on the dextran induced aggregation of red blood cells by use of atomic force microscopy based single cell force spectroscopy (SCFS). The effects of dextran concentration and molecular weight on the interaction energy of adhering RBCs was determined. The results are in good agreement with a model based on the depletion effect and former experimental studies.

  14. Cholesterol depletion disorganizes oocyte membrane rafts altering mouse fertilization.

    Directory of Open Access Journals (Sweden)

    Jorgelina Buschiazzo

    Full Text Available Drastic membrane reorganization occurs when mammalian sperm binds to and fuses with the oocyte membrane. Two oocyte protein families are essential for fertilization, tetraspanins and glycosylphosphatidylinositol-anchored proteins. The firsts are associated to tetraspanin-enriched microdomains and the seconds to lipid rafts. Here we report membrane raft involvement in mouse fertilization assessed by cholesterol modulation using methyl-β-cyclodextrin. Cholesterol removal induced: (1 a decrease of the fertilization rate and index; and (2 a delay in the extrusion of the second polar body. Cholesterol repletion recovered the fertilization ability of cholesterol-depleted oocytes, indicating reversibility of these effects. In vivo time-lapse analyses using fluorescent cholesterol permitted to identify the time-point at which the probe is mainly located at the plasma membrane enabling the estimation of the extent of the cholesterol depletion. We confirmed that the mouse oocyte is rich in rafts according to the presence of the raft marker lipid, ganglioside GM1 on the membrane of living oocytes and we identified the coexistence of two types of microdomains, planar rafts and caveolae-like structures, by terms of two differential rafts markers, flotillin-2 and caveolin-1, respectively. Moreover, this is the first report that shows characteristic caveolae-like invaginations in the mouse oocyte identified by electron microscopy. Raft disruption by cholesterol depletion disturbed the subcellular localization of the signal molecule c-Src and the inhibition of Src kinase proteins prevented second polar body extrusion, consistent with a role of Src-related kinases in fertilization via signaling complexes. Our data highlight the functional importance of intact membrane rafts for mouse fertilization and its dependence on cholesterol.

  15. Photothermal Single Particle Microscopy

    OpenAIRE

    Selmke, Markus; Braun, Marco; Cichos, Frank

    2011-01-01

    Photothermal microscopy has recently complemented single molecule fluorescence microscopy by the detection of individual nano-objects in absorption. Photothermal techniques gain their superior sensitivity by exploiting a heat induced refractive index change around the absorbing nano-object. Numerous new applications to nanoparticles, nanorods and even single molecules have been reported all refering to the fact that photothermal microscopy is an extinction measurement on a heat induced refrac...

  16. 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...

  17. [Artefacts of confocal microscopy].

    Science.gov (United States)

    Vekshin, N L; Frolov, M S

    2014-01-01

    Typical artefacts caused by using confocal fluorescent microscopy while studying living cells are considered. The role of light scattering, mobility, staining, local concentrations, etc. is discussed.

  18. 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

  19. 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

  20. Bridging fluorescence microscopy and electron microscopy

    NARCIS (Netherlands)

    Giepmans, Ben N. G.

    2008-01-01

    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 breakth

  1. New Approach For Prediction Groundwater Depletion

    Science.gov (United States)

    Moustafa, Mahmoud

    2017-01-01

    Current approaches to quantify groundwater depletion involve water balance and satellite gravity. However, the water balance technique includes uncertain estimation of parameters such as evapotranspiration and runoff. The satellite method consumes time and effort. The work reported in this paper proposes using failure theory in a novel way to predict groundwater saturated thickness depletion. An important issue in the failure theory proposed is to determine the failure point (depletion case). The proposed technique uses depth of water as the net result of recharge/discharge processes in the aquifer to calculate remaining saturated thickness resulting from the applied pumping rates in an area to evaluate the groundwater depletion. Two parameters, the Weibull function and Bayes analysis were used to model and analyze collected data from 1962 to 2009. The proposed methodology was tested in a nonrenewable aquifer, with no recharge. Consequently, the continuous decline in water depth has been the main criterion used to estimate the depletion. The value of the proposed approach is to predict the probable effect of the current applied pumping rates on the saturated thickness based on the remaining saturated thickness data. The limitation of the suggested approach is that it assumes the applied management practices are constant during the prediction period. The study predicted that after 300 years there would be an 80% probability of the saturated aquifer which would be expected to be depleted. Lifetime or failure theory can give a simple alternative way to predict the remaining saturated thickness depletion with no time-consuming processes such as the sophisticated software required.

  2. Groundwater depletion embedded in international food trade

    Science.gov (United States)

    Dalin, Carole; Wada, Yoshihide; Kastner, Thomas; Puma, Michael J.

    2017-03-01

    Recent hydrological modelling and Earth observations have located and quantified alarming rates of groundwater depletion worldwide. This depletion is primarily due to water withdrawals for irrigation, but its connection with the main driver of irrigation, global food consumption, has not yet been explored. Here we show that approximately eleven per cent of non-renewable groundwater use for irrigation is embedded in international food trade, of which two-thirds are exported by Pakistan, the USA and India alone. Our quantification of groundwater depletion embedded in the world’s food trade is based on a combination of global, crop-specific estimates of non-renewable groundwater abstraction and international food trade data. A vast majority of the world’s population lives in countries sourcing nearly all their staple crop imports from partners who deplete groundwater to produce these crops, highlighting risks for global food and water security. Some countries, such as the USA, Mexico, Iran and China, are particularly exposed to these risks because they both produce and import food irrigated from rapidly depleting aquifers. Our results could help to improve the sustainability of global food production and groundwater resource management by identifying priority regions and agricultural products at risk as well as the end consumers of these products.

  3. The New MCNP6 Depletion Capability

    Energy Technology Data Exchange (ETDEWEB)

    Fensin, Michael Lorne [Los Alamos National Laboratory; James, Michael R. [Los Alamos National Laboratory; Hendricks, John S. [Los Alamos National Laboratory; Goorley, John T. [Los Alamos National Laboratory

    2012-06-19

    The first MCNP based inline Monte Carlo depletion capability was officially released from the Radiation Safety Information and Computational Center as MCNPX 2.6.0. Both the MCNP5 and MCNPX codes have historically provided a successful combinatorial geometry based, continuous energy, Monte Carlo radiation transport solution for advanced reactor modeling and simulation. However, due to separate development pathways, useful simulation capabilities were dispersed between both codes and not unified in a single technology. MCNP6, the next evolution in the MCNP suite of codes, now combines the capability of both simulation tools, as well as providing new advanced technology, in a single radiation transport code. We describe here the new capabilities of the MCNP6 depletion code dating from the official RSICC release MCNPX 2.6.0, reported previously, to the now current state of MCNP6. NEA/OECD benchmark results are also reported. The MCNP6 depletion capability enhancements beyond MCNPX 2.6.0 reported here include: (1) new performance enhancing parallel architecture that implements both shared and distributed memory constructs; (2) enhanced memory management that maximizes calculation fidelity; and (3) improved burnup physics for better nuclide prediction. MCNP6 depletion enables complete, relatively easy-to-use depletion calculations in a single Monte Carlo code. The enhancements described here help provide a powerful capability as well as dictate a path forward for future development to improve the usefulness of the technology.

  4. 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.

  5. Fluorescence antibunching microscopy

    CERN Document Server

    Schwartz, Osip

    2011-01-01

    Breaking the diffraction limit in microscopy by utilizing quantum properties of light has been the goal of intense research in the recent years. We propose a quantum superresolution technique based on non-classical emission statistics of fluorescent markers, routinely used as contrast labels for bio-imaging. The technique can be readily implemented using standard fluorescence microscopy equipment.

  6. 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

  7. Photothermal Single Particle Microscopy

    CERN Document Server

    Selmke, Markus; Cichos, Frank

    2011-01-01

    Photothermal microscopy has recently complemented single molecule fluorescence microscopy by the detection of individual nano-objects in absorption. Photothermal techniques gain their superior sensitivity by exploiting a heat induced refractive index change around the absorbing nano-object. Numerous new applications to nanoparticles, nanorods and even single molecules have been reported all refering to the fact that photothermal microscopy is an extinction measurement on a heat induced refractive index profile. Here, we show that the actual physical mechanism generating a photothermal signal from a single molecule/particle is fundamentally different from the assumed extinction measurement. Combining photothermal microscopy, light scattering microscopy as well as accurate Mie scattering calculations to single gold nanoparticles, we reveal that the detection mechanism is quantitatively explained by a nanolensing effect of the long range refractive index profile. Our results lay the foundation for future develop...

  8. Local depletion of glycogen with supramaximal exercise in human skeletal muscle fibres.

    Science.gov (United States)

    Gejl, Kasper D; Ørtenblad, Niels; Andersson, Erik; Plomgaard, Peter; Holmberg, Hans-Christer; Nielsen, Joachim

    2017-05-01

    Glycogen is stored in local spatially distinct compartments within skeletal muscle fibres and is the main energy source during supramaximal exercise. Using quantitative electron microscopy, we show that supramaximal exercise induces a differential depletion of glycogen from these compartments and also demonstrate how this varies with fibre types. Repeated exercise alters this compartmentalized glycogen depletion. The results obtained in the present study help us understand the muscle metabolic dynamics of whole body repeated supramaximal exercise, and suggest that the muscle has a compartmentalized local adaptation to repeated exercise, which affects glycogen depletion. Skeletal muscle glycogen is heterogeneously distributed in three separated compartments (intramyofibrillar, intermyofibrillar and subsarcolemmal). Although only constituting 3-13% of the total glycogen volume, the availability of intramyofibrillar glycogen is of particular importance to muscle function. The present study aimed to investigate the depletion of these three subcellular glycogen compartments during repeated supramaximal exercise in elite athletes. Ten elite cross-country skiers (aged 25 ± 4 years, V̇O2 max : 65 ± 4 ml kg(-1)  min(-1) ; mean ± SD) performed four ∼4 min supramaximal sprint time trials (STT 1-4) with 45 min of recovery. The subcellular glycogen volumes in musculus triceps brachii were quantified from electron microscopy images before and after both STT 1 and 4. During STT 1, the depletion of intramyofibrillar glycogen was higher in type 1 fibres [-52%; (-89:-15%)] than type 2 fibres [-15% (-52:22%)] (P = 0.02), whereas the depletion of intermyofibrillar glycogen [main effect: -19% (-33:0%), P = 0.006] and subsarcolemmal glycogen [main effect: -35% (-66:0%), P = 0.03] was similar between fibre types. By contrast, only intermyofibrillar glycogen volume was significantly reduced during STT 4, in both fibre types [main effect: -31% (-50:-11%), P = 0

  9. Ego depletion in visual perception: Ego-depleted viewers experience less ambiguous figure reversal.

    Science.gov (United States)

    Wimmer, Marina C; Stirk, Steven; Hancock, Peter J B

    2017-02-22

    This study examined the effects of ego depletion on ambiguous figure perception. Adults (N = 315) received an ego depletion task and were subsequently tested on their inhibitory control abilities that were indexed by the Stroop task (Experiment 1) and their ability to perceive both interpretations of ambiguous figures that was indexed by reversal (Experiment 2). Ego depletion had a very small effect on reducing inhibitory control (Cohen's d = .15) (Experiment 1). Ego-depleted participants had a tendency to take longer to respond in Stroop trials. In Experiment 2, ego depletion had small to medium effects on the experience of reversal. Ego-depleted viewers tended to take longer to reverse ambiguous figures (duration to first reversal) when naïve of the ambiguity and experienced less reversal both when naïve and informed of the ambiguity. Together, findings suggest that ego depletion has small effects on inhibitory control and small to medium effects on bottom-up and top-down perceptual processes. The depletion of cognitive resources can reduce our visual perceptual experience.

  10. The modality effect of ego depletion: Auditory task modality reduces ego depletion.

    Science.gov (United States)

    Li, Qiong; Wang, Zhenhong

    2016-08-01

    An initial act of self-control that impairs subsequent acts of self-control is called ego depletion. The ego depletion phenomenon has been observed consistently. The modality effect refers to the effect of the presentation modality on the processing of stimuli. The modality effect was also robustly found in a large body of research. However, no study to date has examined the modality effects of ego depletion. This issue was addressed in the current study. In Experiment 1, after all participants completed a handgrip task, one group's participants completed a visual attention regulation task and the other group's participants completed an auditory attention regulation task, and then all participants again completed a handgrip task. The ego depletion phenomenon was observed in both the visual and the auditory attention regulation task. Moreover, participants who completed the visual task performed worse on the handgrip task than participants who completed the auditory task, which indicated that there was high ego depletion in the visual task condition. In Experiment 2, participants completed an initial task that either did or did not deplete self-control resources, and then they completed a second visual or auditory attention control task. The results indicated that depleted participants performed better on the auditory attention control task than the visual attention control task. These findings suggest that altering task modality may reduce ego depletion.

  11. Ozone depletion and chlorine loading potentials

    Science.gov (United States)

    Pyle, John A.; Wuebbles, Donald J.; Solomon, Susan; Zvenigorodsky, Sergei; Connell, Peter; Ko, Malcolm K. W.; Fisher, Donald A.; Stordal, Frode; Weisenstein, Debra

    1991-01-01

    The recognition of the roles of chlorine and bromine compounds in ozone depletion has led to the regulation or their source gases. Some source gases are expected to be more damaging to the ozone layer than others, so that scientific guidance regarding their relative impacts is needed for regulatory purposes. Parameters used for this purpose include the steady-state and time-dependent chlorine loading potential (CLP) and the ozone depletion potential (ODP). Chlorine loading potentials depend upon the estimated value and accuracy of atmospheric lifetimes and are subject to significant (approximately 20-50 percent) uncertainties for many gases. Ozone depletion potentials depend on the same factors, as well as the evaluation of the release of reactive chlorine and bromine from each source gas and corresponding ozone destruction within the stratosphere.

  12. Molten-Salt Depleted-Uranium Reactor

    CERN Document Server

    Dong, Bao-Guo; Gu, Ji-Yuan

    2015-01-01

    The supercritical, reactor core melting and nuclear fuel leaking accidents have troubled fission reactors for decades, and greatly limit their extensive applications. Now these troubles are still open. Here we first show a possible perfect reactor, Molten-Salt Depleted-Uranium Reactor which is no above accident trouble. We found this reactor could be realized in practical applications in terms of all of the scientific principle, principle of operation, technology, and engineering. Our results demonstrate how these reactors can possess and realize extraordinary excellent characteristics, no prompt critical, long-term safe and stable operation with negative feedback, closed uranium-plutonium cycle chain within the vessel, normal operation only with depleted-uranium, and depleted-uranium high burnup in reality, to realize with fission nuclear energy sufficiently satisfying humanity long-term energy resource needs, as well as thoroughly solve the challenges of nuclear criticality safety, uranium resource insuffic...

  13. Self-regulation, ego depletion, and inhibition.

    Science.gov (United States)

    Baumeister, Roy F

    2014-12-01

    Inhibition is a major form of self-regulation. As such, it depends on self-awareness and comparing oneself to standards and is also susceptible to fluctuations in willpower resources. Ego depletion is the state of reduced willpower caused by prior exertion of self-control. Ego depletion undermines inhibition both because restraints are weaker and because urges are felt more intensely than usual. Conscious inhibition of desires is a pervasive feature of everyday life and may be a requirement of life in civilized, cultural society, and in that sense it goes to the evolved core of human nature. Intentional inhibition not only restrains antisocial impulses but can also facilitate optimal performance, such as during test taking. Self-regulation and ego depletion- may also affect less intentional forms of inhibition, even chronic tendencies to inhibit. Broadly stated, inhibition is necessary for human social life and nearly all societies encourage and enforce it.

  14. Depletion of the nuclear Fermi sea

    CERN Document Server

    Rios, A; Dickhoff, W H

    2009-01-01

    The short-range and tensor components of the bare nucleon-nucleon interaction induce a sizeable depletion of low momenta in the ground state of a nuclear many-body system. The self-consistent Green's function method within the ladder approximation provides an \\textit{ab-initio} description of correlated nuclear systems that accounts properly for these effects. The momentum distribution predicted by this approach is analyzed in detail, with emphasis on the depletion of the lowest momentum state. The temperature, density, and nucleon asymmetry (isospin) dependence of the depletion of the Fermi sea is clarified. A connection is established between the momentum distribution and the time-ordered components of the self-energy, which allows for an improved interpretation of the results. The dependence on the underlying nucleon-nucleon interaction provides quantitative estimates of the importance of short-range and tensor correlations in nuclear systems.

  15. Sensitivity study of control rod depletion coefficients

    OpenAIRE

    Blomberg, Joel

    2015-01-01

    This report investigates the sensitivity of the control rod depletion coefficients, Sg, to different input parameters and how this affects the accumulated 10B depletion, β. Currently the coefficients are generated with PHOENIX4, but the geometries can be more accurately simulated in McScram. McScram is used to calculate Control Rod Worth, which in turn is used to calculate Nuclear End Of Life, and Sg cannot be generated in the current version of McScram. Therefore, it is also analyzed whether...

  16. Zn precipitation and Li depletion in Zn implanted ZnO

    Energy Technology Data Exchange (ETDEWEB)

    Chan, K. S.; Jagadish, C.; Wong-Leung, J., E-mail: jenny.wongleung@anu.edu.au [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 2601 (Australia); Vines, L.; Svensson, B. G. [Department of Physics/Centre for Materials Science and Nanotechnology, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo (Norway); Li, L. [Australian National Fabrication Facility, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 2601 (Australia)

    2016-07-11

    Ion implantation of Zn substituting elements in ZnO has been shown to result in a dramatic Li depletion of several microns in hydrothermally grown ZnO. This has been ascribed to a burst of mobile Zn interstials. In this study, we seek to understand the reason behind this interstitial mediated transient enhanced diffusion in Li-containing ZnO samples after Zn implantation. ZnO wafers were implanted with Zn to two doses, 5 × 10{sup 15} cm{sup −2} and 1 × 10{sup 17} cm{sup −2}. Secondary ion mass spectrometry was carried out to profile the Li depletion depth for different annealing temperatures between 600 and 800 °C. The 800 °C annealing had the most significant Li depletion of close to 60 μm. Transmission electron microscopy (TEM) was carried out in selected samples to identify the reason behind the Li depletion. In particular, TEM investigations of samples annealed at 750 °C show significant Zn precipitation just below the depth of the projected range of the implanted ions. We propose that the Zn precipitation is indicative of Zn supersaturation. Both the Li depletion and Zn precipitation are competing synchronous processes aimed at reducing the excess Zn interstitials.

  17. Diagnostic electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Dickersin, G.R.

    1988-01-01

    In this book the author presents a comprehensive reference text on diagnostic electron microscopy. Throughout the book he illustrates how ultrastructural identification can be helpful for the recognition of cell type and the identification of mechanisms of pathogenesis in various diseases. In addition to electron microscopy photographs, there are also numerous light microscopy photographs for comparison. This text presents the classification of neoplasms in the order and arrangement most familiar to the pathologist. Contents: Introduction; Diagram of a Normal Cell; Normal Cell Function; Embryology; Neoplasms; Infectious Agents; Metabolic Diseases; Renal Diseases; Skeletal Muscle and Peripheral Nerve Diseases; Index.

  18. The interaction of manganese nanoparticles with PC-12 cells induces dopamine depletion.

    Science.gov (United States)

    Hussain, Saber M; Javorina, Amanda K; Schrand, Amanda M; Duhart, Helen M; Ali, Syed F; Schlager, John J

    2006-08-01

    This investigation was designed to determine whether nano-sized manganese oxide (Mn-40 nm) particles would induce dopamine (DA) depletion in a cultured neuronal phenotype, PC-12 cells, similar to free ionic manganese (Mn(2+)). Cells were exposed to Mn-40 nm, Mn(2+) (acetate), or known cytotoxic silver nanoparticles (Ag-15 nm) for 24 h. Phase-contrast microscopy studies show that Mn-40 nm or Mn(2+) exposure did not greatly change morphology of PC-12 cells. However, Ag-15 nm and AgNO(3) produce cell shrinkage and irregular membrane borders compared to control cells. Further microscopic studies at higher resolution demonstrated that Mn-40 nm nanoparticles and agglomerates were effectively internalized by PC-12 cells. Mitochondrial reduction activity, a sensitive measure of particle and metal cytotoxicity, showed only moderate toxicity for Mn-40 nm compared to similar Ag-15 nm and Mn(2+) doses. Mn-40 nm and Mn(2+) dose dependently depleted DA and its metabolites, dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), while Ag-15 nm only significantly reduced DA and DOPAC at concentrations of 50 mug/ml. Therefore, the DA depletion of Mn-40 nm was most similar to Mn(2+), which is known to induce concentration-dependent DA depletion. There was a significant increase (> 10-fold) in reactive oxygen species (ROS) with Mn-40 nm exposure, suggesting that increased ROS levels may participate in DA depletion. These results clearly demonstrate that nanoscale manganese can deplete DA, DOPAC, and HVA in a dose-dependent manner. Further study is required to evaluate the specific intracellular distribution of Mn-40 nm nanoparticles, metal dissolution rates in cells and cellular matrices, if DA depletion is induced in vivo, and the propensity of Mn nanoparticles to cross the blood-brain barrier or be selectively uptaken by nasal epithelium.

  19. Quantitative pupil analysis in stimulated emission depletion microscopy using phase retrieval

    DEFF Research Database (Denmark)

    Kromann, Emil B; Gould, Travis J; Juette, Manuel F;

    2012-01-01

    no instrument modifications, for obtaining an equivalent to the complex pupil function at the back aperture of the objective and show that it provides quantitative information about aberration sources (including aberrations induced by the objective or sample). We show the accuracy of this field representation...

  20. Contrasts between Antarctic and Arctic ozone depletion.

    Science.gov (United States)

    Solomon, Susan; Portmann, Robert W; Thompson, David W J

    2007-01-09

    This work surveys the depth and character of ozone depletion in the Antarctic and Arctic using available long balloon-borne and ground-based records that cover multiple decades from ground-based sites. Such data reveal changes in the range of ozone values including the extremes observed as polar air passes over the stations. Antarctic ozone observations reveal widespread and massive local depletion in the heart of the ozone "hole" region near 18 km, frequently exceeding 90%. Although some ozone losses are apparent in the Arctic during particular years, the depth of the ozone losses in the Arctic are considerably smaller, and their occurrence is far less frequent. Many Antarctic total integrated column ozone observations in spring since approximately the 1980s show values considerably below those ever observed in earlier decades. For the Arctic, there is evidence of some spring season depletion of total ozone at particular stations, but the changes are much less pronounced compared with the range of past data. Thus, the observations demonstrate that the widespread and deep ozone depletion that characterizes the Antarctic ozone hole is a unique feature on the planet.

  1. Global Warming: Lessons from Ozone Depletion

    Science.gov (United States)

    Hobson, Art

    2010-01-01

    My teaching and textbook have always covered many physics-related social issues, including stratospheric ozone depletion and global warming. The ozone saga is an inspiring good-news story that's instructive for solving the similar but bigger problem of global warming. Thus, as soon as students in my physics literacy course at the University of…

  2. Global Warming: Lessons from Ozone Depletion

    Science.gov (United States)

    Hobson, Art

    2010-01-01

    My teaching and textbook have always covered many physics-related social issues, including stratospheric ozone depletion and global warming. The ozone saga is an inspiring good-news story that's instructive for solving the similar but bigger problem of global warming. Thus, as soon as students in my physics literacy course at the University of…

  3. “When the going gets tough, who keeps going?” Depletion sensitivity moderates the ego-depletion effect

    Science.gov (United States)

    Salmon, Stefanie J.; Adriaanse, Marieke A.; De Vet, Emely; Fennis, Bob M.; De Ridder, Denise T. D.

    2014-01-01

    Self-control relies on a limited resource that can get depleted, a phenomenon that has been labeled ego-depletion. We argue that individuals may differ in their sensitivity to depleting tasks, and that consequently some people deplete their self-control resource at a faster rate than others. In three studies, we assessed individual differences in depletion sensitivity, and demonstrate that depletion sensitivity moderates ego-depletion effects. The Depletion Sensitivity Scale (DSS) was employed to assess depletion sensitivity. Study 1 employs the DSS to demonstrate that individual differences in sensitivity to ego-depletion exist. Study 2 shows moderate correlations of depletion sensitivity with related self-control concepts, indicating that these scales measure conceptually distinct constructs. Study 3 demonstrates that depletion sensitivity moderates the ego-depletion effect. Specifically, participants who are sensitive to depletion performed worse on a second self-control task, indicating a stronger ego-depletion effect, compared to participants less sensitive to depletion. PMID:25009523

  4. “When the going gets tough, who keeps going?” Depletion sensitivity moderates the ego-depletion effect

    NARCIS (Netherlands)

    Salmon, S.J.; Adriaanse, M.A.; Vet, de E.W.M.L.; Fennis, B.M.; Ridder, de D.T.D.

    2014-01-01

    Self-control relies on a limited resource that can get depleted, a phenomenon that has been labeled ego-depletion. We argue that individuals may differ in their sensitivity to depleting tasks, and that consequently some people deplete their self-control resource at a faster rate than others. In thre

  5. Photothermal imaging scanning microscopy

    Science.gov (United States)

    Chinn, Diane; Stolz, Christopher J.; Wu, Zhouling; Huber, Robert; Weinzapfel, Carolyn

    2006-07-11

    Photothermal Imaging Scanning Microscopy produces a rapid, thermal-based, non-destructive characterization apparatus. Also, a photothermal characterization method of surface and subsurface features includes micron and nanoscale spatial resolution of meter-sized optical materials.

  6. 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

  7. 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.

  8. Tour de force microscopy

    OpenAIRE

    Mervyn Miles; Massimo Antognozzi; Heiko Haschke; Jamie Hobbs; Andrew Humphris; Terence McMaster

    2003-01-01

    Scanning probe microscopy (SPM) is capable of imaging synthetic polymers and biomolecular systems at sub-molecular resolution, without the need for staining or coating, in a range of environments including gas and liquid, so offering major advantages over other forms of microscopy. However, there are some limitations, which could be alleviated by (i) reducing the force interaction between the probe and specimen and (ii) increasing the rate of imaging. New developments in instrumentation from ...

  9. How Depleted is the MORB mantle?

    Science.gov (United States)

    Hofmann, A. W.; Hart, S. R.

    2015-12-01

    Knowledge of the degree of mantle depletion of highly incompatible elements is critically important for assessing Earth's internal heat production and Urey number. Current views of the degree of MORB source depletion are dominated by Salters and Stracke (2004), and Workman and Hart (2005). The first is based on an assessment of average MORB compositions, whereas the second considers trace element data of oceanic peridotites. Both require an independent determination of one absolute concentration, Lu (Salters & Stracke), or Nd (Workman & Hart). Both use parent-daughter ratios Lu/Hf, Sm/Nd, and Rb/Sr calculated from MORB isotopes combined with continental-crust extraction models, as well as "canonical" trace element ratios, to boot-strap the full range of trace element abundances. We show that the single most important factor in determining the ultimate degree of incompatible element depletion in the MORB source lies in the assumptions about the timing of continent extraction, exemplified by continuous extraction versus simple two-stage models. Continued crust extraction generates additional, recent mantle depletion, without affecting the isotopic composition of the residual mantle significantly. Previous emphasis on chemical compositions of MORB and/or peridotites has tended to obscure this. We will explore the effect of different continent extraction models on the degree of U, Th, and K depletion in the MORB source. Given the uncertainties of the two most popular models, the uncertainties of U and Th in DMM are at least ±50%, and this impacts the constraints on the terrestrial Urey ratio. Salters, F.J.M. and Stracke, A., 2004, Geochem. Geophys. Geosyst. 5, Q05004. Workman, R.K. and Hart, S.R., 2005, EPSL 231, 53-72.

  10. Aberrations and adaptive optics in super-resolution microscopy.

    Science.gov (United States)

    Booth, Martin; Andrade, Débora; Burke, Daniel; Patton, Brian; Zurauskas, Mantas

    2015-08-01

    As one of the most powerful tools in the biological investigation of cellular structures and dynamic processes, fluorescence microscopy has undergone extraordinary developments in the past decades. The advent of super-resolution techniques has enabled fluorescence microscopy - or rather nanoscopy - to achieve nanoscale resolution in living specimens and unravelled the interior of cells with unprecedented detail. The methods employed in this expanding field of microscopy, however, are especially prone to the detrimental effects of optical aberrations. In this review, we discuss how super-resolution microscopy techniques based upon single-molecule switching, stimulated emission depletion and structured illumination each suffer from aberrations in different ways that are dependent upon intrinsic technical aspects. We discuss the use of adaptive optics as an effective means to overcome this problem.

  11. 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.

  12. Neutron-activation revisited: the depletion and depletion-activation models.

    Science.gov (United States)

    Abdel-Rahman, Wamied; Podgorsak, Ervin B

    2005-02-01

    The growth of a radioactive daughter in neutron activation is commonly described with the saturation model that ignores the consumption of parent nuclei during the radio-activation process. This approach is not valid when radioactive sources with high specific activities are produced or when the particle fluence rates used are very high. Assuming a constant neutron fluence rate throughout the activation target, a neutron-activation model that accounts for the depletion in parent nuclei is introduced. This depletion model is governed by relationships similar to those describing the parent-daughter-granddaughter decay series, and, in contrast to the saturation model, correctly predicts the practical limit of the daughter specific activity, irrespective of the particle fluence rate. Also introduced is a neutron-activation model that in addition to parent depletion accounts for the neutron activation of daughter nuclei in situations where the cross section for this effect is high. The model is referred to as the depletion-activation model and it provides the most realistic description for the daughter specific activity in neutron activation. Three specific neutron activation examples of interest to medical physics are presented: activation of molybdenum-98 into molybdenum-99 described by the saturation model; activation of cobalt-59 into cobalt-60 described by the depletion model; and activation of iridium-191 into iridium-192 described by the depletion-activation model.

  13. Replacements For Ozone-Depleting Foaming Agents

    Science.gov (United States)

    Blevins, Elana; Sharpe, Jon B.

    1995-01-01

    Fluorinated ethers used in place of chlorofluorocarbons and hydrochlorofluorocarbons. Replacement necessary because CFC's and HCFC's found to contribute to depletion of ozone from upper atmosphere, and manufacture and use of them by law phased out in near future. Two fluorinated ethers do not have ozone-depletion potential and used in existing foam-producing equipment, designed to handle liquid blowing agents soluble in chemical ingredients that mixed to make foam. Any polyurethane-based foams and several cellular plastics blown with these fluorinated ethers used in processes as diverse as small batch pours, large sprays, or double-band lamination to make insulation for private homes, commercial buildings, shipping containers, and storage tanks. Fluorinated ethers proved useful as replacements for CFC refrigerants and solvents.

  14. Assessment of Preferred Depleted Uranium Disposal Forms

    Energy Technology Data Exchange (ETDEWEB)

    Croff, A.G.; Hightower, J.R.; Lee, D.W.; Michaels, G.E.; Ranek, N.L.; Trabalka, J.R.

    2000-06-01

    The Department of Energy (DOE) is in the process of converting about 700,000 metric tons (MT) of depleted uranium hexafluoride (DUF6) containing 475,000 MT of depleted uranium (DU) to a stable form more suitable for long-term storage or disposal. Potential conversion forms include the tetrafluoride (DUF4), oxide (DUO2 or DU3O8), or metal. If worthwhile beneficial uses cannot be found for the DU product form, it will be sent to an appropriate site for disposal. The DU products are considered to be low-level waste (LLW) under both DOE orders and Nuclear Regulatory Commission (NRC) regulations. The objective of this study was to assess the acceptability of the potential DU conversion products at potential LLW disposal sites to provide a basis for DOE decisions on the preferred DU product form and a path forward that will ensure reliable and efficient disposal.

  15. Ecological and corrosion behavior of depleted uranium

    Directory of Open Access Journals (Sweden)

    Stojanović Mirjana D.

    2015-01-01

    Full Text Available Environmental pollution with radionuclides, particularly uranium and its decay products is a serious global problem. The current scientific studies estimated that the contamination originating from TENORM, caused by nuclear and non-nuclear technologies, has significantly increased natural level of radioactivity in the last thirty years. During the last decades all the more were talking about the "new pollutant" - depleted uranium (DU, which has been used in anti-tank penetrators because of its high density, penetration and pyrophoric properties. It is estimated that during the Gulf War, the war in Bosnia and Yugoslavia and during the invasion of Iraq, 1.4 million missiles with depleted uranium was fired. During the NATO aggression against the ex Yugoslavia in 1999., 112 locations in Kosovo and Metohija, 12 locations in southern Serbia and two locations in Montenegro were bombed. On this occasion, approximately 10 tons of depleted uranium were entered into the environment, mainly on land, where the degree of contamination ranged from 200 Bq / kg to 235 000 Bq/kg, which is up to 1000 times higher than the natural level. Fourteen years ago there was very little information about the behavior of ecological systems damaged by DU penetrators fired. Today, unfortunately, we are increasingly faced with the ―invisible threat" of depleted uranium, which has a strong radioactive and hemotoxic impact on human health. Present paper provides a detailed overview of the current understanding of corrosion and corrosion behavior of DU and environmental factors that control corrosion, together with indicators of environmental impact in order to highlight areas that need further attention in developing remediation programs.

  16. The ultimate disposition of depleted uranium

    Energy Technology Data Exchange (ETDEWEB)

    Lemons, T.R. [Uranium Enrichment Organization, Oak Ridge, TN (United States)

    1991-12-31

    Depleted uranium (DU) is produced as a by-product of the uranium enrichment process. Over 340,000 MTU of DU in the form of UF{sub 6} have been accumulated at the US government gaseous diffusion plants and the stockpile continues to grow. An overview of issues and objectives associated with the inventory management and the ultimate disposition of this material is presented.

  17. Effective Depletion Potential of Colloidal Spheres

    Institute of Scientific and Technical Information of China (English)

    LI Wei-Hua; MA Hong-Ru

    2004-01-01

    @@ A new semianalytical method, which is a combination of the density functional theory with Rosenfeld density functional and the Ornstein-Zernike equation, is proposed for the calculation of the effective depletion potentials between a pair of big spheres immersed in a small hard sphere fluid. The calculated results are almost identical to the integral equation method with the Percus-Yevick approximation, and are also in agreement well with the Monte Carlo simulation results.

  18. 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.

  19. Optical imaging. Expansion microscopy.

    Science.gov (United States)

    Chen, Fei; Tillberg, Paul W; Boyden, Edward S

    2015-01-30

    In optical microscopy, fine structural details are resolved by using refraction to magnify images of a specimen. We discovered that by synthesizing a swellable polymer network within a specimen, it can be physically expanded, resulting in physical magnification. By covalently anchoring specific labels located within the specimen directly to the polymer network, labels spaced closer than the optical diffraction limit can be isotropically separated and optically resolved, a process we call expansion microscopy (ExM). Thus, this process can be used to perform scalable superresolution microscopy with diffraction-limited microscopes. We demonstrate ExM with apparent ~70-nanometer lateral resolution in both cultured cells and brain tissue, performing three-color superresolution imaging of ~10(7) cubic micrometers of the mouse hippocampus with a conventional confocal microscope.

  20. Barium depletion in hollow cathode emitters

    Energy Technology Data Exchange (ETDEWEB)

    Polk, James E., E-mail: james.e.polk@jpl.nasa.gov; Mikellides, Ioannis G.; Katz, Ira [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109 (United States); Capece, Angela M. [Graduate Aerospace Laboratories, California Institute of Technology, Pasadena, California 91125 (United States)

    2016-01-14

    Dispenser hollow cathodes rely on a consumable supply of Ba released by BaO-CaO-Al{sub 2}O{sub 3} source material in the pores of a tungsten matrix to maintain a low work function surface. The examination of cathode emitters from long duration tests shows deposits of tungsten at the downstream end that appear to block the flow of Ba from the interior. In addition, a numerical model of Ba transport in the cathode plasma indicates that the Ba partial pressure in the insert may exceed the equilibrium vapor pressure of the dominant Ba-producing reaction, and it was postulated previously that this would suppress Ba loss in the upstream part of the emitter. New measurements of the Ba depletion depth from a cathode insert operated for 8200 h reveal that Ba loss is confined to a narrow region near the downstream end, confirming this hypothesis. The Ba transport model was modified to predict the depletion depth with time. A comparison of the calculated and measured depletion depths gives excellent qualitative agreement, and quantitative agreement was obtained assuming an insert temperature 70 °C lower than measured beginning-of-life values.

  1. Mitochondrial DNA depletion analysis by pseudogene ratioing.

    Science.gov (United States)

    Swerdlow, Russell H; Redpath, Gerard T; Binder, Daniel R; Davis, John N; VandenBerg, Scott R

    2006-01-30

    The mitochondrial DNA (mtDNA) depletion status of rho(0) cell lines is typically assessed by hybridization or polymerase chain reaction (PCR) experiments, in which the failure to hybridize mtDNA or amplify mtDNA using mtDNA-directed primers suggests thorough mitochondrial genome removal. Here, we report the use of an mtDNA pseudogene ratioing technique for the additional confirmation of rho0 status. Total genomic DNA from a U251 human glioma cell line treated with ethidium bromide was amplified using primers designed to anneal either mtDNA or a previously described nuclear DNA-embedded mtDNA pseudogene (mtDNApsi). The resultant PCR product was used to generate plasmid clones. Sixty-two plasmid clones were genotyped, and all arose from mtDNApsi template. These data allowed us to determine with 95% confidence that the resultant mtDNA-depleted cell line contains less than one copy of mtDNA per 10 cells. Unlike previous hybridization or PCR-based analyses of mtDNA depletion, this mtDNApsi ratioing technique does not rely on interpretation of a negative result, and may prove useful as an adjunct for the determination of rho0 status or mtDNA copy number.

  2. Conventional transmission electron microscopy.

    Science.gov (United States)

    Winey, Mark; Meehl, Janet B; O'Toole, Eileen T; Giddings, Thomas H

    2014-02-01

    Researchers have used transmission electron microscopy (TEM) to make contributions to cell biology for well over 50 years, and TEM continues to be an important technology in our field. We briefly present for the neophyte the components of a TEM-based study, beginning with sample preparation through imaging of the samples. We point out the limitations of TEM and issues to be considered during experimental design. Advanced electron microscopy techniques are listed as well. Finally, we point potential new users of TEM to resources to help launch their project.

  3. Second harmonic generation microscopy

    DEFF Research Database (Denmark)

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

    2010-01-01

    Myofibers and collagen show non-linear optical properties enabling imaging using second harmonic generation (SHG) microscopy. The technique is evaluated for use as a tool for real-time studies of thermally induced changes in thin samples of unfixed and unstained pork. The forward and the backward......-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...

  4. Basic confocal microscopy

    Directory of Open Access Journals (Sweden)

    Manuela Monti

    2012-03-01

    Full Text Available This is an eleven chapter’s effort done by a bunch of Authors coordinated by Prof. R.L. Price and W.G. Jerome (who have personally written almost half of the book that with great skills are revealing us the secrets of confocal microscopy. Considering the significant progresses in different fields of biology, confocal microscopy is extremely important to dynamically see all the different molecules involved in the controlling networks build up by gene expressions in time and space. Necessary prerequisites to accomplish such goals are some fundamental microscopic technologies well and clearly presented in the first chapters....

  5. 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...

  6. Spectrally encoded confocal microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tearney, G.J.; Webb, R.H.; Bouma, B.E. [Wellman Laboratories of Photomedicine, Massachusetts General Hospital, 50 Blossom Street, BAR 703, Boston, Massachusetts 02114 (United States)

    1998-08-01

    An endoscope-compatible, submicrometer-resolution scanning confocal microscopy imaging system is presented. This approach, spectrally encoded confocal microscopy (SECM), uses a quasi-monochromatic light source and a transmission diffraction grating to detect the reflectivity simultaneously at multiple points along a transverse line within the sample. Since this method does not require fast spatial scanning within the probe, the equipment can be miniaturized and incorporated into a catheter or endoscope. Confocal images of an electron microscope grid were acquired with SECM to demonstrate the feasibility of this technique. {copyright} {ital 1998} {ital Optical Society of America}

  7. Correlative Stochastic Optical Reconstruction Microscopy and Electron Microscopy

    OpenAIRE

    Doory Kim; Deerinck, Thomas J.; Sigal, Yaron M.; Babcock, Hazen P.; Ellisman, Mark H.; Xiaowei Zhuang

    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 ima...

  8. Confocal scanning microscopy

    DEFF Research Database (Denmark)

    Bariani, Paolo

    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...

  9. 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.

  10. Single particle electron microscopy

    NARCIS (Netherlands)

    Boekema, Egbert J.; Folea, Mihaela; Kouril, Roman; Kouřil, 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 EM

  11. Scanning ultrafast electron microscopy

    Science.gov (United States)

    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 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. PMID:20696933

  12. Ballistic hole magnetic microscopy

    NARCIS (Netherlands)

    Haq, E.; Banerjee, T.; Siekman, M.H.; Lodder, J.C.; Jansen, R.

    2005-01-01

    A technique to study nanoscale spin transport of holes is presented: ballistic hole magnetic microscopy. The tip of a scanning tunneling microscope is used to inject hot electrons into a ferromagnetic heterostructure, where inelastic decay creates a distribution of electron-hole pairs. Spin-dependen

  13. Ballistic hole magnetic microscopy

    NARCIS (Netherlands)

    Haq, E.; Banerjee, T.; Siekman, M.H.; Lodder, J.C.; Jansen, R.

    2005-01-01

    A technique to study nanoscale spin transport of holes is presented: ballistic hole magnetic microscopy. The tip of a scanning tunneling microscope is used to inject hot electrons into a ferromagnetic heterostructure, where inelastic decay creates a distribution of electron-hole pairs.

  14. Lithium Depletion in Fully Convective Pre-Main Sequence Stars

    CERN Document Server

    Bildsten, L; Matzner, C D; Ushomirsky, G; Bildsten, Lars; Brown, Edward F.; Matzner, Christopher D.; Ushomirsky, Greg

    1996-01-01

    We present an analytic calculation of the thermonuclear depletion of lithium in contracting, fully convective, pre-main sequence stars of mass M 0.08 M_sun) and for constraining the masses of lithium depleted stars.

  15. (JASR) Vol. 12, No. 2, 2012 DEPLETING FOREST RESOURCES OF ...

    African Journals Online (AJOL)

    HP

    undisturbed lands leading to depletion of the forest cover and increase on the sand dunes .... depletion of the ozone layer leading to a rise in global temperature. ... Nigeria has good correlation with greenhouse gas emission which can cause ...

  16. Depletions at Browns Park National Wildlife Refuge [Draft

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Estimated depletion associated with the operation of Spitzie Marsh in Browns Park National Wildlife Refuge. Attached are the methods used to estimate depletion....

  17. Self-regulatory depletion increases emotional reactivity in the amygdala

    National Research Council Canada - National Science Library

    Wagner, Dylan D; Heatherton, Todd F

    2013-01-01

    ... attention control task that required effortful inhibition (depletion group) or not (control group). Compared to the control group, depleted participants showed increased activity in the left amygdala to negative but not to positive or neutral scenes...

  18. Children's Models of the Ozone Layer and Ozone Depletion.

    Science.gov (United States)

    Christidou, Vasilia; Koulaidis, Vasilis

    1996-01-01

    The views of 40 primary students on ozone and its depletion were recorded through individual, semi-structured interviews. The data analysis resulted in the formation of a limited number of models concerning the distribution and role of ozone in the atmosphere, the depletion process, and the consequences of ozone depletion. Identifies five target…

  19. Children's Models of the Ozone Layer and Ozone Depletion.

    Science.gov (United States)

    Christidou, Vasilia; Koulaidis, Vasilis

    1996-01-01

    The views of 40 primary students on ozone and its depletion were recorded through individual, semi-structured interviews. The data analysis resulted in the formation of a limited number of models concerning the distribution and role of ozone in the atmosphere, the depletion process, and the consequences of ozone depletion. Identifies five target…

  20. 26 CFR 1.642(e)-1 - Depreciation and depletion.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 8 2010-04-01 2010-04-01 false Depreciation and depletion. 1.642(e)-1 Section 1... (CONTINUED) INCOME TAXES Estates, Trusts, and Beneficiaries § 1.642(e)-1 Depreciation and depletion. An estate or trust is allowed the deductions for depreciation and depletion, but only to the extent...

  1. A modern depleted uranium manufacturing facility

    Energy Technology Data Exchange (ETDEWEB)

    Zagula, T.A.

    1995-07-01

    The Specific Manufacturing Capabilities (SMC) Project located at the Idaho National Engineering Laboratory (INEL) and operated by Lockheed Martin Idaho Technologies Co. (LMIT) for the Department of Energy (DOE) manufactures depleted uranium for use in the U.S. Army MIA2 Abrams Heavy Tank Armor Program. Since 1986, SMC has fabricated more than 12 million pounds of depleted uranium (DU) products in a multitude of shapes and sizes with varying metallurgical properties while maintaining security, environmental, health and safety requirements. During initial facility design in the early 1980`s, emphasis on employee safety, radiation control and environmental consciousness was gaining momentum throughout the DOE complex. This fact coupled with security and production requirements forced design efforts to focus on incorporating automation, local containment and computerized material accountability at all work stations. The result was a fully automated production facility engineered to manufacture DU armor packages with virtually no human contact while maintaining security, traceability and quality requirements. This hands off approach to handling depleted uranium resulted in minimal radiation exposures and employee injuries. Construction of the manufacturing facility was complete in early 1986 with the first armor package certified in October 1986. Rolling facility construction was completed in 1987 with the first certified plate produced in the fall of 1988. Since 1988 the rolling and manufacturing facilities have delivered more than 2600 armor packages on schedule with 100% final product quality acceptance. During this period there was an annual average of only 2.2 lost time incidents and a single individual maximum radiation exposure of 150 mrem. SMC is an example of designing and operating a facility that meets regulatory requirements with respect to national security, radiation control and personnel safety while achieving production schedules and product quality.

  2. Kr ion irradiation study of the depleted-uranium alloys

    Science.gov (United States)

    Gan, J.; Keiser, D. D.; Miller, B. D.; Kirk, M. A.; Rest, J.; Allen, T. R.; Wachs, D. M.

    2010-12-01

    Fuel development for the reduced enrichment research and test reactor (RERTR) program is tasked with the development of new low enrichment uranium nuclear fuels that can be employed to replace existing high enrichment uranium fuels currently used in some research reactors throughout the world. For dispersion type fuels, radiation stability of the fuel-cladding interaction product has a strong impact on fuel performance. Three depleted-uranium alloys are cast for the radiation stability studies of the fuel-cladding interaction product using Kr ion irradiation to investigate radiation damage from fission products. SEM analysis indicates the presence of the phases of interest: U(Al, Si) 3, (U, Mo)(Al, Si) 3, UMo 2Al 20, U 6Mo 4Al 43 and UAl 4. Irradiations of TEM disc samples were conducted with 500 keV Kr ions at 200 °C to ion doses up to 2.5 × 10 19 ions/m 2 (˜10 dpa) with an Kr ion flux of 10 16 ions/m 2/s (˜4.0 × 10 -3 dpa/s). Microstructural evolution of the phases relevant to fuel-cladding interaction products was investigated using transmission electron microscopy.

  3. 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

  4. Capstone Depleted Uranium Aerosols: Generation and Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Parkhurst, MaryAnn; Szrom, Fran; Guilmette, Ray; Holmes, Tom; Cheng, Yung-Sung; Kenoyer, Judson L.; Collins, John W.; Sanderson, T. Ellory; Fliszar, Richard W.; Gold, Kenneth; Beckman, John C.; Long, Julie

    2004-10-19

    In a study designed to provide an improved scientific basis for assessing possible health effects from inhaling depleted uranium (DU) aerosols, a series of DU penetrators was fired at an Abrams tank and a Bradley fighting vehicle. A robust sampling system was designed to collect aerosols in this difficult environment and continuously monitor the sampler flow rates. Aerosols collected were analyzed for uranium concentration and particle size distribution as a function of time. They were also analyzed for uranium oxide phases, particle morphology, and dissolution in vitro. The resulting data provide input useful in human health risk assessments.

  5. Heatstroke Pathophysiology: The Energy Depletion Model

    Science.gov (United States)

    1989-06-12

    Pathophysiology: The Energy Depletion Model Roger W. Hubbard, Ph.D., Director Heat Research Division U. S. Army Research Institute of Environmental...Medicine Natick, MA 01760-5007 USA Send correspondence to: Roger W. Hubbard, Ph.D. Director Heat Research Division USARIEM Kansas St Natick, MA 01760...The NaK-Pump. Part B: Celular Asoects J.C. Skou, J.G. Normy, A.B. Maunsback, and M. Esmann (Eds) New York: Alan R. Uss, 1988, pp. 171-194. 54: Lewis

  6. Scientific assessment of ozone depletion: 1991

    Science.gov (United States)

    1991-01-01

    Over the past few years, there have been highly significant advances in the understanding of the impact of human activities on the Earth's stratospheric ozone layer and the influence of changes in chemical composition of the radiative balance of the climate system. Specifically, since the last international scientific review (1989), there have been five major advances: (1) global ozone decreases; (2) polar ozone; (3) ozone and industrial halocarbons; (4) ozone and climate relations; and (5) ozone depletion potentials (ODP's) and global warming potentials (GWP's). These topics and others are discussed.

  7. Correlation between cosmic rays and ozone depletion.

    Science.gov (United States)

    Lu, Q-B

    2009-03-20

    This Letter reports reliable satellite data in the period of 1980-2007 covering two full 11-yr cosmic ray (CR) cycles, clearly showing the correlation between CRs and ozone depletion, especially the polar ozone loss (hole) over Antarctica. The results provide strong evidence of the physical mechanism that the CR-driven electron-induced reaction of halogenated molecules plays the dominant role in causing the ozone hole. Moreover, this mechanism predicts one of the severest ozone losses in 2008-2009 and probably another large hole around 2019-2020, according to the 11-yr CR cycle.

  8. Optical assessment of phytoplankton nutrient depletion

    DEFF Research Database (Denmark)

    Heath, M.R.; Richardson, Katherine; Kiørboe, Thomas

    1990-01-01

    status (carbon/nitrogen ratio) and the absorption ratio that was independent of light and temperature climate. The absorption ratio for nutrient-replete cells was shown to vary between taxonomic groups. However, the inter-specific variation was less than the differences observed between nutrient......-replete and nutrient-depleted cells. The field data suggest that the absorption ratio may be a useful indicator of nutritional status of natural phytoplankton populations, and can be used to augment the interpretation of other data....

  9. The Time of Shipbuilding Order Depletion

    Institute of Scientific and Technical Information of China (English)

    Reporter Xing Dan

    2012-01-01

    In 2012, shipbuilding market is facing even colder weather. Depletion of orders, deals that can only ensure cost recovery ndustry which has already bankruptcy of ship yards one after another are also torturing this had many uncertainties. Some shipbuilding enterprises are trying to survive by cutting off parts of their business, some enterprises are leaving like the horses migrating on the African grassland, only those horses that have fights with crocodiles will reach the fertile land and enjoy the next warm spring. the business. It is survived the fierce

  10. RESERVOIR CAPACITY DEPLETION ON ACCOUNT OF SEDIMENTATION

    Institute of Scientific and Technical Information of China (English)

    Prabhata K.SWAMEE

    2001-01-01

    Capacity depletion is an important information required for planning of multipurpose reservoirs. It is a complex phenomenon involving diverse fields like surface hydrology, sediment transport, varied flow hydraulics and soil consolidation. Proper assessment of capacity reduction is helpful in ascertaining the life of the reservoir and the project benefits for cost/benefit analysis. In this study dimensionally consistent equations for deposition volume and the trap efficiency have been obtained. Methods of obtaining the parameters involved these equations have also been indicated. It was found that there is good agreement with the field data. It is hoped that the equations are useful to design engineer.

  11. Quantitative deconvolution microscopy.

    Science.gov (United States)

    Goodwin, Paul C

    2014-01-01

    The light microscope is an essential tool for the study of cells, organelles, biomolecules, and subcellular dynamics. A paradox exists in microscopy whereby the higher the needed lateral resolution, the more the image is degraded by out-of-focus information. This creates a significant need to generate axial contrast whenever high lateral resolution is required. One strategy for generating contrast is to measure or model the optical properties of the microscope and to use that model to algorithmically reverse some of the consequences of high-resolution imaging. Deconvolution microscopy implements model-based methods to enable the full diffraction-limited resolution of the microscope to be exploited even in complex and living specimens. © 2014 Elsevier Inc. All rights reserved.

  12. Simulations and observations of plasma depletion, ion composition, and airglow emissions in two auroral ionospheric depletion experiments

    Science.gov (United States)

    Yau, A. W.; Whalen, B. A.; Harris, F. R.; Gattinger, R. L.; Pongratz, M. B.

    1985-01-01

    Observations of plasma depletion, ion composition modification, and airglow emissions in the Waterhole experiments are presented. The detailed ion chemistry and airglow emission processes related to the ionospheric hole formation in the experiment are examined, and observations are compared with computer simulation results. The latter indicate that the overall depletion rates in different parts of the depletion region are governed by different parameters.

  13. Glutathione Depletion Induces Spermatogonial Cell Autophagy.

    Science.gov (United States)

    Mancilla, Héctor; Maldonado, Rodrigo; Cereceda, Karina; Villarroel-Espíndola, Franz; Montes de Oca, Marco; Angulo, Constanza; Castro, Maite A; Slebe, Juan C; Vera, Juan C; Lavandero, Sergio; Concha, Ilona I

    2015-10-01

    The development and survival of male germ cells depend on the antioxidant capacity of the seminiferous tubule. Glutathione (GSH) plays an important role in the antioxidant defenses of the spermatogenic epithelium. Autophagy can act as a pro-survival response during oxidative stress or nutrient deficiency. In this work, we evaluated whether autophagy is involved in spermatogonia-type germ cell survival during severe GSH deficiency. We showed that the disruption of GSH metabolism with l-buthionine-(S,R)-sulfoximine (BSO) decreased reduced (GSH), oxidized (GSSG) glutathione content, and GSH/GSSG ratio in germ cells, without altering reactive oxygen species production and cell viability, evaluated by 2',7'-dichlorodihydrofluorescein (DCF) fluorescence and exclusion of propidium iodide assays, respectively. Autophagy was assessed by processing the endogenous protein LC3I and observing its sub-cellular distribution. Immunoblot and immunofluorescence analysis showed a consistent increase in LC3II and accumulation of autophagic vesicles under GSH-depletion conditions. This condition did not show changes in the level of phosphorylation of AMP-activated protein kinase (AMPK) or the ATP content. A loss in S-glutathionylated protein pattern was also observed. However, inhibition of autophagy resulted in decreased ATP content and increased caspase-3/7 activity in GSH-depleted germ cells. These findings suggest that GSH deficiency triggers an AMPK-independent induction of autophagy in germ cells as an adaptive stress response. © 2015 Wiley Periodicals, Inc.

  14. Halocarbon ozone depletion and global warming potentials

    Science.gov (United States)

    Cox, Richard A.; Wuebbles, D.; Atkinson, R.; Connell, Peter S.; Dorn, H. P.; Derudder, A.; Derwent, Richard G.; Fehsenfeld, F. C.; Fisher, D.; Isaksen, Ivar S. A.

    1990-01-01

    Concern over the global environmental consequences of fully halogenated chlorofluorocarbons (CFCs) has created a need to determine the potential impacts of other halogenated organic compounds on stratospheric ozone and climate. The CFCs, which do not contain an H atom, are not oxidized or photolyzed in the troposphere. These compounds are transported into the stratosphere where they decompose and can lead to chlorine catalyzed ozone depletion. The hydrochlorofluorocarbons (HCFCs or HFCs), in particular those proposed as substitutes for CFCs, contain at least one hydrogen atom in the molecule, which confers on these compounds a much greater sensitivity toward oxidation by hydroxyl radicals in the troposphere, resulting in much shorter atmospheric lifetimes than CFCs, and consequently lower potential for depleting ozone. The available information is reviewed which relates to the lifetime of these compounds (HCFCs and HFCs) in the troposphere, and up-to-date assessments are reported of the potential relative effects of CFCs, HCFCs, HFCs, and halons on stratospheric ozone and global climate (through 'greenhouse' global warming).

  15. Equatorial airglow depletions induced by thermospheric winds

    Energy Technology Data Exchange (ETDEWEB)

    Meriwether, J.W.; Biondi, M.A.; Anderson, D.N.

    1985-08-01

    Interferometric observations on the 630.0 nm nightglow brightness at the equatorial station at Arequipa, Peru (16.2 S, 71.4 W geographic, 3.2 S dip latitude) have revealed widespread areas of airglow depletion, with reductions in intensity as large as factors of 3 or 4. These depletions correlated closely with large increases of the equatorward (northward) wind and the 630.0 nm kinetic temperature. On occasion, the usually small meridional wind reached a velocity of 100 m/s near 22h LT lasting for 1 to 2 hours. The temperature increases of 100K or more existed only in the poleware (southward) direction. Comparisons with modeling calculations suggest that this effect results from an upward movement of the ionosphere along the inclined magnetic field lines, driven by the equatorward neutral wind. The airglow column integrated emission rate is consequently decreased by the slower rate of formation and subsequent dissociative recombination of molecular oxygen ions within the higher F-layer. We conclude that the transient period of equatorward wind is a result of the passage of the midnight pressure bulge. (Author)

  16. Equatorial airglow depletions induced by thermospheric winds

    Energy Technology Data Exchange (ETDEWEB)

    Meriwether J.W. Jr.; Biondi, M.A.; Anderson, D.N.

    1985-08-01

    Interferometric observations of the 630.0 nm nightglow brightness at the equatorial station of Arequipa. Peru (16.2/sup 0/S, 71.4/sup 0/W geographic, 3.2/sup 0/S dip latitude) have revealed widespread areas of airglow depletion, with reductions in intensity as large as factors of 3 or 4. These depletions correlated closely with large increases of the equatorward (northward) wind and the 630.0 nm kinetic temperature. On occasion, the usually small meridonal wind reached a velocity of 100 m/s near 22/sup h/ LT lasting for 1 or 2 hours. The temperature increases of 10 K or more existed only in the poleward (southward) direction. Comparisons with modeling calculations suggest that this effect results from an upward movement of the ionosphere along the inclined magnetic field lines, driven by the equatorward neutral wind. The airglow column integrated emission rate is consequently decreased by the slower rate of formation and subsequent dissociative recombination of molecular oxygen ions within the higher F-layer. We conclude that the transient period of equatorward wind is a result of the passage of the midnight pressure bulge.

  17. Abundances and Depletions of Interstellar Oxygen

    Science.gov (United States)

    Jensen, A. G.; Rachford, B. L.; Snow, T. P.

    2003-12-01

    We extend previous work on interstellar oxygen abundances with the addition of data from the Far Ultraviolet Spectroscopic Explorer (FUSE). We report on the abundance of interstellar neutral oxygen (OI) for several sightlines, using data from FUSE, the International Spectroscopic Explorer (IUE), and the Hubble Space Telescope (HST). OI column densities are derived by measuring the equivalent widths of several ultraviolet absorption lines, and subsequently fitting those to a curve of growth. The column densities of our best-constrained sightlines show a ratio of O/H that agrees with the current best solar value if dust is considered. We do not see evidence of enhanced depletion of gas-phase oxygen that is systematically variable with respect to the physical parameters of different environments (e.g., reddening or molecular fraction). The column densities of our less well-constrained sightlines show some scatter in O/H, but many agree with the solar value to within errors. We discuss these results in the context of deriving the best methods for determining interstellar abundances, the unresolved question of the best value for O/H in the interstellar medium (ISM), the O/H ratio observed in Galactic stars, and the depletion of gas-phase oxygen onto dust grains. Financial support for this research has been provided by the National Science Foundation GK-12 Program and NASA contract NAS 5-32985.

  18. CD97 antibody depletes granulocytes in mice under conditions of acute inflammation via a Fc receptor-dependent mechanism.

    Science.gov (United States)

    Veninga, Henrike; de Groot, Dorien M; McCloskey, Natalie; Owens, Bronwyn M; Dessing, Mark C; Verbeek, J Sjef; Nourshargh, Sussan; van Eenennaam, Hans; Boots, Annemieke M; Hamann, Jörg

    2011-03-01

    Antibodies to the pan-leukocyte adhesion-GPCR CD97 efficiently block neutrophil recruitment in mice, thereby reducing antibacterial host defense, inflammatory disease, and hematopoietic stem cell mobilization. Here, we investigated the working mechanism of the CD97 antibody 1B2. Applying sterile models of inflammation, intravital microscopy, and mice deficient for the CD97L CD55, the complement component C3, or the FcR common γ-chain, we show that 1B2 acts in vivo independent of ligand-binding interference by depleting PMN granulocytes in bone marrow and blood. Granulocyte depletion with 1B2 involved FcR but not complement activation and was associated with increased serum levels of TNF and other proinflammatory cytokines. Notably, depletion of granulocytes by CD97 antibody required acute inflammation, suggesting a mechanism of conditional, antibody-mediated granulocytopenia.

  19. Cord blood glutathione depletion in preterm infants: correlation with maternal cysteine depletion.

    Directory of Open Access Journals (Sweden)

    Alice Küster

    Full Text Available BACKGROUND: Depletion of blood glutathione (GSH, a key antioxidant, is known to occur in preterm infants. OBJECTIVE: Our aim was to determine: 1 whether GSH depletion is present at the time of birth; and 2 whether it is associated with insufficient availability of cysteine (cys, the limiting GSH precursor, or a decreased capacity to synthesize GSH. METHODOLOGY: Sixteen mothers delivering very low birth weight infants (VLBW, and 16 mothers delivering healthy, full term neonates were enrolled. Immediately after birth, erythrocytes from umbilical vein, umbilical artery, and maternal blood were obtained to assess GSH [GSH] and cysteine [cys] concentrations, and the GSH synthesis rate was determined from the incorporation of labeled cysteine into GSH in isolated erythrocytes ex vivo, measured using gas chromatography mass spectrometry. PRINCIPAL FINDINGS: Compared with mothers delivering at full term, mothers delivering prematurely had markedly lower erythrocyte [GSH] and [cys] and these were significantly depressed in VLBW infants, compared with term neonates. A strong correlation was found between maternal and fetal GSH and cysteine levels. The capacity to synthesize GSH was as high in VLBW as in term infants. CONCLUSION: The current data demonstrate that: 1 GSH depletion is present at the time of birth in VLBW infants; 2 As VLBW neonates possess a fully active capacity to synthesize glutathione, the depletion may arise from inadequate cysteine availability, potentially due to maternal depletion. Further studies would be needed to determine whether maternal-fetal cysteine transfer is decreased in preterm infants, and, if so, whether cysteine supplementation of mothers at risk of delivering prematurely would strengthen antioxidant defense in preterm neonates.

  20. Electrochemical force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    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.

  1. Depleted Uranium Penetrators : Hazards and Safety

    Directory of Open Access Journals (Sweden)

    S. S. Rao

    1997-01-01

    Full Text Available The depleted uranium (DU alloy is a state-of-the-art material for kinetic energy penetrators due to its superior ballistic performance. Several countries use DU penetrators in their main battle tanks. There is no gamma radiation hazard to the crew members from stowage of DO rounds. Open air firing can result in environmental contamination and associated hazards due to airborne particles containing essentially U/sub 3/0/sub 8/ and UO/sub 2/. Inhalation of polluted air only through respirators or nose masks and refraining form ingestion of water or food materials from contaminated environment are safety measures for avoiding exposure to uranium and its toxicity. Infusion of sodium bicarbonate helps in urinary excretion of uranium that may have entered the body.

  2. Arctic Ozone Depletion from UARS MLS Measurements

    Science.gov (United States)

    Manney, G. L.

    1995-01-01

    Microwave Limb Sounder (MLS) measurements of ozone during four Arctic winters are compared. The evolution of ozone in the lower stratosphere is related to temperature, chlorine monoxide (also measured by MLS), and the evolution of the polar vortex. Lagrangian transport calculations using winds from the United Kingdom Meteorological Office's Stratosphere-Troposphere Data Assimilation system are used to estimate to what extent the evolution of lower stratospheric ozone is controlled by dynamics. Observations, along with calculations of the expected dynamical behavior, show evidence for chemical ozone depletion throughout most of the Arctic lower stratospheric vortex during the 1992-93 middle and late winter, and during all of the 1994-95 winter that was observed by MLS. Both of these winters were unusually cold and had unusually cold and had unusually strong Arctic polar vortices compared to meteorological data over the past 17 years.

  3. Ozone depletion following future volcanic eruptions

    Science.gov (United States)

    Eric Klobas, J.; Wilmouth, David M.; Weisenstein, Debra K.; Anderson, James G.; Salawitch, Ross J.

    2017-07-01

    While explosive volcanic eruptions cause ozone loss in the current atmosphere due to an enhancement in the availability of reactive chlorine following the stratospheric injection of sulfur, future eruptions are expected to increase total column ozone as halogen loading approaches preindustrial levels. The timing of this shift in the impact of major volcanic eruptions on the thickness of the ozone layer is poorly known. Modeling four possible climate futures, we show that scenarios with the smallest increase in greenhouse gas concentrations lead to the greatest risk to ozone from heterogeneous chemical processing following future eruptions. We also show that the presence in the stratosphere of bromine from natural, very short-lived biogenic compounds is critically important for determining whether future eruptions will lead to ozone depletion. If volcanic eruptions inject hydrogen halides into the stratosphere, an effect not considered in current ozone assessments, potentially profound reductions in column ozone would result.

  4. Kinetic depletion model for pellet ablation

    Energy Technology Data Exchange (ETDEWEB)

    Kuteev, Boris V. [State Technical Univ., St. Petersburg (Russian Federation)

    2001-11-01

    A kinetic model for depletion effect, which determines pellet ablation when the pellet passes a rational magnetic surface, is formulated. The model predicts a moderate decrease of the ablation rate compared with the earlier considered monoenergy versions [1, 2]. For typical T-10 conditions the ablation rate reduces by a reactor of 2.5 when the 1-mm pellet penetrates through the plasma center. A substantial deceleration of pellets -about 15% per centimeter of low shire rational q region; is predicted. Penetration for Low Field Side and High Field Side injections is considered taking into account modification of the electron distribution function by toroidal magnetic field. It is shown that Shafranov shift and toroidal effects yield the penetration length for HFS injection higher by a factor of 1.5. This fact should be taken into account when plasma-shielding effects on penetration are considered. (author)

  5. Anxiety, ego depletion, and sports performance.

    Science.gov (United States)

    Englert, Chris; Bertrams, Alex

    2012-10-01

    In the present article, we analyzed the role of self-control strength and state anxiety in sports performance. We tested the hypothesis that self-control strength and state anxiety interact in predicting sports performance on the basis of two studies, each using a different sports task (Study 1: performance in a basketball free throw task, N = 64; Study 2: performance in a dart task, N = 79). The patterns of results were as expected in both studies: Participants with depleted self-control strength performed worse in the specific tasks as their anxiety increased, whereas there was no significant relation for participants with fully available self-control strength. Furthermore, different degrees of available self-control strength did not predict performance in participants who were low in state anxiety, but did in participants who were high in state anxiety. Thus increasing self-control strength could reduce the negative anxiety effects in sports and improve athletes' performance under pressure.

  6. Seasonal iron depletion in temperate shelf seas

    Science.gov (United States)

    Birchill, Antony J.; Milne, Angela; Woodward, E. Malcolm S.; Harris, Carolyn; Annett, Amber; Rusiecka, Dagmara; Achterberg, Eric P.; Gledhill, Martha; Ussher, Simon J.; Worsfold, Paul J.; Geibert, Walter; Lohan, Maeve C.

    2017-09-01

    Our study followed the seasonal cycling of soluble (SFe), colloidal (CFe), dissolved (DFe), total dissolvable (TDFe), labile particulate (LPFe), and total particulate (TPFe) iron in the Celtic Sea (NE Atlantic Ocean). Preferential uptake of SFe occurred during the spring bloom, preceding the removal of CFe. Uptake and export of Fe during the spring bloom, coupled with a reduction in vertical exchange, led to Fe deplete surface waters (<0.2 nM DFe; 0.11 nM LPFe, 0.45 nM TDFe, and 1.84 nM TPFe) during summer stratification. Below the seasonal thermocline, DFe concentrations increased from spring to autumn, mirroring NO3- and consistent with supply from remineralized sinking organic material, and cycled independently of particulate Fe over seasonal timescales. These results demonstrate that summer Fe availability is comparable to the seasonally Fe limited Ross Sea shelf and therefore is likely low enough to affect phytoplankton growth and species composition.

  7. Modelling chemical depletion profiles in regolith

    Science.gov (United States)

    Brantley, S.L.; Bandstra, J.; Moore, J.; White, A.F.

    2008-01-01

    Chemical or mineralogical profiles in regolith display reaction fronts that document depletion of leachable elements or minerals. A generalized equation employing lumped parameters was derived to model such ubiquitously observed patterns:C = frac(C0, frac(C0 - Cx = 0, Cx = 0) exp (??ini ?? over(k, ??) ?? x) + 1)Here C, Cx = 0, and Co are the concentrations of an element at a given depth x, at the top of the reaction front, or in parent respectively. ??ini is the roughness of the dissolving mineral in the parent and k???? is a lumped kinetic parameter. This kinetic parameter is an inverse function of the porefluid advective velocity and a direct function of the dissolution rate constant times mineral surface area per unit volume regolith. This model equation fits profiles of concentration versus depth for albite in seven weathering systems and is consistent with the interpretation that the surface area (m2 mineral m- 3 bulk regolith) varies linearly with the concentration of the dissolving mineral across the front. Dissolution rate constants can be calculated from the lumped fit parameters for these profiles using observed values of weathering advance rate, the proton driving force, the geometric surface area per unit volume regolith and parent concentration of albite. These calculated values of the dissolution rate constant compare favorably to literature values. The model equation, useful for reaction fronts in both steady-state erosional and quasi-stationary non-erosional systems, incorporates the variation of reaction affinity using pH as a master variable. Use of this model equation to fit depletion fronts for soils highlights the importance of buffering of pH in the soil system. Furthermore, the equation should allow better understanding of the effects of important environmental variables on weathering rates. ?? 2008.

  8. Multi-pass microscopy

    Science.gov (United States)

    Juffmann, Thomas; Klopfer, Brannon B.; Frankort, Timmo L. I.; Haslinger, Philipp; Kasevich, Mark A.

    2016-09-01

    Microscopy of biological specimens often requires low light levels to avoid damage. This yields images impaired by shot noise. An improved measurement accuracy at the Heisenberg limit can be achieved exploiting quantum correlations. If sample damage is the limiting resource, an equivalent limit can be reached by passing photons through a specimen multiple times sequentially. Here we use self-imaging cavities and employ a temporal post-selection scheme to present full-field multi-pass polarization and transmission micrographs with variance reductions of 4.4+/-0.8 dB (11.6+/-0.8 dB in a lossless setup) and 4.8+/-0.8 dB, respectively, compared with the single-pass shot-noise limit. If the accuracy is limited by the number of detected probe particles, our measurements show a variance reduction of 25.9+/-0.9 dB. The contrast enhancement capabilities in imaging and in diffraction studies are demonstrated with nanostructured samples and with embryonic kidney 293T cells. This approach to Heisenberg-limited microscopy does not rely on quantum state engineering.

  9. Correlative stochastic optical reconstruction microscopy and electron microscopy.

    Directory of Open Access Journals (Sweden)

    Doory Kim

    Full Text Available 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.

  10. Effect of greenhouse gas emissions on stratospheric ozone depletion

    OpenAIRE

    Velders GJM; LLO

    1997-01-01

    The depletion of the ozone layer is caused mainly by the increase in emissions of chlorine- and bromine-containing compounds like CFCs, halons, carbon tetrachloride, methyl chloroform and methyl bromide. Emissions of greenhouse gases can affect the depletion of the ozone layer through atmospheric interaction. We studied the interactions in the atmosphere between the greenhouse effect and stratospheric ozone depletion from the point of view of past and future emissions of the anthropogenic com...

  11. Effect of greenhouse gas emissions on stratospheric ozone depletion

    OpenAIRE

    Velders GJM; LLO

    1997-01-01

    The depletion of the ozone layer is caused mainly by the increase in emissions of chlorine- and bromine-containing compounds like CFCs, halons, carbon tetrachloride, methyl chloroform and methyl bromide. Emissions of greenhouse gases can affect the depletion of the ozone layer through atmospheric interaction. We studied the interactions in the atmosphere between the greenhouse effect and stratospheric ozone depletion from the point of view of past and future emissions of the anthropogenic com...

  12. A Novel Depletion-Mode MOS Gated Emitter Shorted Thyristor

    Institute of Scientific and Technical Information of China (English)

    张鹤鸣; 戴显英; 张义门; 马晓华; 林大松

    2000-01-01

    A Novel MOS-gated thyristor, depletion-mode MOS gated emitter shorted thyristor (DMST),and its two structures are proposed. In DMST,the channel of depletion-mode MOS makes the thyristor emitter-based junction inherently short. The operation of the device is controlled by the interruption and recovery of the depletion-mode MOS P channel. The perfect properties have been demonstrated by 2-D numerical simulations and the tests on the fabricated chips.

  13. Characterization of Polymer Blends: Optical Microscopy (*Polarized, Interference and Phase Contrast Microscopy*) and Confocal Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ramanathan, Nathan Muruganathan [ORNL; Darling, Seth B. [Argonne National Laboratory (ANL)

    2015-01-01

    Chapter 15 surveys the characterization of macro, micro and meso morphologies of polymer blends by optical microscopy. Confocal Microscopy offers the ability to view the three dimensional morphology of polymer blends, popular in characterization of biological systems. Confocal microscopy uses point illumination and a spatial pinhole to eliminate out-of focus light in samples that are thicker than the focal plane.

  14. Mantle depletion and metasomatism recorded in orthopyroxene in highly depleted peridotites

    DEFF Research Database (Denmark)

    Scott, James; Liu, Jingao; Pearson, D. Graham;

    2016-01-01

    Although trace element concentrations in clinopyroxene serve as a useful tool for assessing the depletion and enrichment history of mantle peridotites, this is not applicable for peridotites in which the clinopyroxene component has been consumed (~ 25% partial melting). Orthopyroxene persists.......6), high spinel Cr# (commonly > 45) and low orthopyroxene Al2O3 (generally compositions shows that all samples, even the most refractory, have undergone metasomatism by small volume light rare earth element-bearing agents. Measured...

  15. What is superresolution microscopy?

    CERN Document Server

    Bechhoefer, John

    2014-01-01

    I explain what is, is not, and is only sort of superresolution microscopy. I discuss optical resolution, first in terms of diffraction theory, then in terms of linear systems theory, and finally in terms of techniques that use prior information, nonlinearity, and other tricks to improve performance. The discussion reveals two classes of superresolution: Pseudo superresolution techniques improve images up to the diffraction limit but not much beyond. True superresolution techniques allow substantial, useful improvements beyond the diffraction limit. The two classes are distinguished by their scaling of resolution with photon counts. Understanding the limits to imaging resolution involves concepts that pertain to almost any measurement problem, implying that the framework given here has broad application beyond optics.

  16. [Confocal laser scanning microscopy].

    Science.gov (United States)

    Ulrich, M

    2015-07-01

    Reflectance confocal microscopy (RCM) allows the in vivo evaluation of melanocytic and nonmelanocytic skin tumours with high sensitivity and specificity. RCM represents an optical imaging technique, which enables us to examine the skin at high resolution. Today, RCM represents not only an interesting tool for dermatologic research but has also been introduced as a diagnostic tool in every day clinical practice. As such, RCM is applied for improvement of skin cancer diagnosis adjunct to clinical and dermatoscopic examination. In combination with dermatoscopy RCM has shown an increased specificity with similar sensitivity. In this regard RCM helps to decrease the rate of unnecessary biopsies of benign lesions. Despite its use in dermatooncology RCM may also be used for diagnosis and monitoring of inflammatory diseases. Future developments include technical improvements, teledermatology solutions and the application of ex vivo RCM in Moh's micrographic surgery.

  17. Effects of Plectin Depletion on Keratin Network Dynamics and Organization.

    Directory of Open Access Journals (Sweden)

    Marcin Moch

    Full Text Available The keratin intermediate filament cytoskeleton protects epithelial cells against various types of stress and is involved in fundamental cellular processes such as signaling, differentiation and organelle trafficking. These functions rely on the cell type-specific arrangement and plasticity of the keratin system. It has been suggested that these properties are regulated by a complex cycle of assembly and disassembly. The exact mechanisms responsible for the underlying molecular processes, however, have not been clarified. Accumulating evidence implicates the cytolinker plectin in various aspects of the keratin cycle, i.e., by acting as a stabilizing anchor at hemidesmosomal adhesion sites and the nucleus, by affecting keratin bundling and branching and by linkage of keratins to actin filament and microtubule dynamics. In the present study we tested these hypotheses. To this end, plectin was downregulated by shRNA in vulvar carcinoma-derived A431 cells. As expected, integrin β4- and BPAG-1-positive hemidesmosomal structures were strongly reduced and cytosolic actin stress fibers were increased. In addition, integrins α3 and β1 were reduced. The experiments furthermore showed that loss of plectin led to a reduction in keratin filament branch length but did not alter overall mechanical properties as assessed by indentation analyses using atomic force microscopy and by displacement analyses of cytoplasmic superparamagnetic beads using magnetic tweezers. An increase in keratin movement was observed in plectin-depleted cells as was the case in control cells lacking hemidesmosome-like structures. Yet, keratin turnover was not significantly affected. We conclude that plectin alone is not needed for keratin assembly and disassembly and that other mechanisms exist to guarantee proper keratin cycling under steady state conditions in cultured single cells.

  18. The depletion potential in one, two and three dimensions

    Indian Academy of Sciences (India)

    R Roth; P-M König

    2005-06-01

    We study the behavior of the depletion potential in binary mixtures of hard particles in one, two, and three dimensions within the framework of a general theory for depletion potential using density functional theory. By doing so we extend earlier studies of the depletion potential in three dimensions to the cases of = 1 and 2 about which little is known, despite their importance for experiments. We also verify scaling relations between depletion potentials in sphere–sphere and wall–sphere geometries in = 3 and in disk–disk and wall–disk geometries in = 2, which originate from geometrical considerations.

  19. Ultrasonic Force Microscopies

    Science.gov (United States)

    Kolosov, Oleg; Briggs, Andrew

    Ultrasonic Force Microscopy, or UFM, allows combination of two apparently mutually exclusive requirements for the nanomechanical probe—high stiffness for the efficient indentation and high mechanical compliance that brings force sensitivity. Somewhat inventively, UFM allows to combine these two virtues in the same cantilever by using indention of the sample at high frequency, when cantilever is very rigid, but detecting the result of this indention at much lower frequency. That is made possible due to the extreme nonlinearity of the nanoscale tip-surface junction force-distance dependence, that acts as "mechanical diode" detecting ultrasound in AFM. After introducing UFM principles, we discuss features of experimental UFM implementation, and the theory of contrast in this mode, progressing to quantitative measurements of contact stiffness. A variety of UFM applications ranging from semiconductor quantum nanostructures, graphene, very large scale integrated circuits, and reinforced ceramics to polymer composites and biological materials is presented via comprehensive imaging gallery accompanied by the guidance for the optimal UFM measurements of these materials. We also address effects of adhesion and topography on the elasticity imaging and the approaches for reducing artifacts connected with these effects. This is complemented by another extremely useful feature of UFM—ultrasound induced superlubricity that allows damage free imaging of materials ranging from stiff solid state devices and graphene to biological materials. Finally, we proceed to the exploration of time-resolved nanoscale phenomena using nonlinear mixing of multiple vibration frequencies in ultrasonic AFM—Heterodyne Force Microscopy, or HFM, that also include mixing of ultrasonic vibration with other periodic physical excitations, eg. electrical, photothermal, etc. Significant section of the chapter analyzes the ability of UFM and HFM to detect subsurface mechanical inhomogeneities, as well as

  20. Regret causes ego-depletion and finding benefits in the regrettable events alleviates ego-depletion.

    Science.gov (United States)

    Gao, Hongmei; Zhang, Yan; Wang, Fang; Xu, Yan; Hong, Ying-Yi; Jiang, Jiang

    2014-01-01

    This study tested the hypotheses that experiencing regret would result in ego-depletion, while finding benefits (i.e., "silver linings") in the regret-eliciting events counteracted the ego-depletion effect. Using a modified gambling paradigm (Experiments 1, 2, and 4) and a retrospective method (Experiments 3 and 5), five experiments were conducted to induce regret. Results revealed that experiencing regret undermined performance on subsequent tasks, including a paper-and-pencil calculation task (Experiment 1), a Stroop task (Experiment 2), and a mental arithmetic task (Experiment 3). Furthermore, finding benefits in the regret-eliciting events improved subsequent performance (Experiments 4 and 5), and this improvement was mediated by participants' perceived vitality (Experiment 4). This study extended the depletion model of self-regulation by considering emotions with self-conscious components (in our case, regret). Moreover, it provided a comprehensive understanding of how people felt and performed after experiencing regret and after finding benefits in the events that caused the regret.

  1. If ego depletion cannot be studied using identical tasks, it is not ego depletion.

    Science.gov (United States)

    Lange, Florian

    2015-01-01

    The hypothesis that human self-control capacities are fueled by glucose has been challenged on multiple grounds. A recent study by Lange and Eggert adds to this criticism by presenting two powerful but unsuccessful attempts to replicate the effect of sugar drinks on ego depletion. The dual-task paradigms employed in these experiments have been criticized for involving identical self-control tasks, a methodology that has been argued to reduce participants' willingness to exert self-control. The present article addresses this criticism by demonstrating that there is no indication to believe that the study of glucose effects on ego depletion should be restricted to paradigms using dissimilar acts of self-control. Failures to observe such effects in paradigms involving identical tasks pose a serious problem to the proposal that self-control exhaustion might be reversed by rinsing or ingesting glucose. In combination with analyses of statistical credibility, the experiments by Lange and Eggert suggest that the influence of sugar on ego depletion has been systematically overestimated.

  2. [AGGREGATION OF METABOLICALLY DEPLETED HUMAN ERYTHROCYTES].

    Science.gov (United States)

    Sheremet'ev, Yu A; Popovicheva, A N; Rogozin, M M; Levin, G Ya

    2016-01-01

    An aggregation of erythrocytes in autologous plasma after blood storage for 14 days at 4 °C was studied using photometry and light microscopy. The decrease of ATP content, the formation of echinocytes and spheroechinocytes, the decrease of rouleaux form of erythrocyte aggregation were observed during the storage. On the other hand the aggregates of echinocytes were formed in the stored blood. The addition of plasma from the fresh blood didn't restore the normal discocytic shape and aggregation of erythrocytes in the stored blood. The possible mechanisms of erythrocytes and echinocytes aggregation are discussed.

  3. Primitive red alga Cyanidioschyzon merolae accumulates storage glucan and triacylglycerol under nitrogen depletion.

    Science.gov (United States)

    Takusagawa, Mari; Nakajima, Yohei; Saito, Takafumi; Misumi, Osami

    2016-07-14

    Most microalgae accumulate neutral lipids, including triacylglycerol (TAG), into spherical structures called lipid bodies (LBs) under environmental stress conditions such as nutrient depletion. In green algae, starch accumulation precedes TAG accumulation, and the starch is thought to be a substrate for TAG synthesis. However, the relationship between TAG synthesis and the starch content in red algae, as well as how TAG accumulation is regulated, is unclear. In this study, we cultured the primitive red alga Cyanidioschyzon merolae under nitrogen-depleted conditions, and monitored the formation of starch granules (SGs) and LBs using microscopy. SGs stained with potassium iodide were observed at 24 h; however, LBs stained specifically with BODIPY 493/503 were observed after 48 h. Quantitative analysis of neutral sugar and cytomorphological semi-quantitative analysis of TAG accumulation also supported these results. Thus, the accumulation of starch occurred and preceded the accumulation of TAG in cells of C. merolae. However, TAG accumulation was not accompanied by a decrease in the starch content, suggesting that the starch is a major carbon storage sink, at least under nitrogen-depleted conditions. Quantitative real-time PCR revealed that the mRNA levels of genes involved in starch and TAG synthesis rarely changed during the culture period, suggesting that starch and TAG synthesis in C. merolae are not controlled through gene transcription but at other stages, such as translation and/or enzymatic activity.

  4. Tylosin depletion in edible tissues of turkeys.

    Science.gov (United States)

    Montesissa, C; De Liguoro, M; Santi, A; Capolongo, F; Biancotto, G

    1999-10-01

    The depletion of tylosin residues in edible turkey tissues was followed after 3 days of administration of tylosin tartrate at 500 mg l-1 in drinking water, to 30 turkeys. Immediately after the end of the treatment (day 0) and at day 1, 3, 5 and 10 of withdrawal, six turkeys (three males and three females) per time were sacrificed and samples of edible tissues were collected. Tissue homogenates were extracted, purified and analysed by HPLC according to a method previously published for the analysis of tylosin residues in pig tissues. In all tissues, tylosin residues were already below the detection limits of 50 micrograms kg-1 at time zero. However, in several samples of tissues (skin + fat, liver, kidney, muscle), from the six turkeys sacrificed at that time, one peak corresponding to an unknown tylosin equivalent was detected at measurable concentrations. The identification of this unknown compound was performed by LC-MS/MS analysis of the extracts from incurred samples. The mass fragmentation of the compound was consistent with the structure of tylosin D (the alcoholic derivative of tylosin A), the major metabolite of tylosin previously recovered and identified in tissues and/or excreta from treated chickens, cattle and pigs.

  5. Sprog-krop-sted: Dialektsamfundets meningsskabende orden

    DEFF Research Database (Denmark)

    Quist, Pia

    2015-01-01

    As a consequence of the effects of globalization the concept of place is obtaining increased attention among social dialectologists and sociolinguists. Is it still possible to assume a cultural and historical bond between places, people and languages in a time characterized by migration, geographic...

  6. Byer og Bygninger - Betydninger, rum og sted

    DEFF Research Database (Denmark)

    Juel-Christiansen, Carsten

    2013-01-01

    En analyse af relationer mellem privat og offentligt i udviklingen af det offentlige rums arkitektur. Eksemplerne indeholder elementer af kunstnerisk udviklingsvirksomhed......En analyse af relationer mellem privat og offentligt i udviklingen af det offentlige rums arkitektur. Eksemplerne indeholder elementer af kunstnerisk udviklingsvirksomhed...

  7. Det mærkede sted

    DEFF Research Database (Denmark)

    Larsen, Jo Krøjer

    Afhandlingen undersøger kønnede subjektiveringsprocesser i arebjdslivet. Med afsær i spørgsmålet om køn og ligestilling som en del af tillidsrepræsentanters faglige arbejde retter afhandlingens fokus sig mid, hvordan kroppen - som et sansende og følende element - kan indplaceres og forstås i to d...

  8. Podocyte depletion causes glomerulosclerosis: diphtheria toxin-induced podocyte depletion in rats expressing human diphtheria toxin receptor transgene

    National Research Council Canada - National Science Library

    Wharram, Bryan L; Goyal, Meera; Wiggins, Jocelyn E; Sanden, Silja K; Hussain, Sabiha; Filipiak, Wanda E; Saunders, Thomas L; Dysko, Robert C; Kohno, Kenji; Holzman, Lawrence B; Wiggins, Roger C

    2005-01-01

    .... For determining the causal relationship between podocyte depletion and glomerulosclerosis, a transgenic rat strain in which the human diphtheria toxin receptor is specifically expressed in podocytes was developed...

  9. Molecular Switch for Sub-Diffraction Laser Lithography by Photoenol Intermediate-State Cis-Trans Isomerization.

    Science.gov (United States)

    Mueller, Patrick; Zieger, Markus M; Richter, Benjamin; Quick, Alexander S; Fischer, Joachim; Mueller, Jonathan B; Zhou, Lu; Nienhaus, Gerd Ulrich; Bastmeyer, Martin; Barner-Kowollik, Christopher; Wegener, Martin

    2017-06-27

    Recent developments in stimulated-emission depletion (STED) microscopy have led to a step change in the achievable resolution and allowed breaking the diffraction limit by large factors. The core principle is based on a reversible molecular switch, allowing for light-triggered activation and deactivation in combination with a laser focus that incorporates a point or line of zero intensity. In the past years, the concept has been transferred from microscopy to maskless laser lithography, namely direct laser writing (DLW), in order to overcome the diffraction limit for optical lithography. Herein, we propose and experimentally introduce a system that realizes such a molecular switch for lithography. Specifically, the population of intermediate-state photoenol isomers of α-methyl benzaldehydes generated by two-photon absorption at 700 nm fundamental wavelength can be reversibly depleted by simultaneous irradiation at 440 nm, suppressing the subsequent Diels-Alder cycloaddition reaction which constitutes the chemical core of the writing process. We demonstrate the potential of the proposed mechanism for STED-inspired DLW by covalently functionalizing the surface of glass substrates via the photoenol-driven STED-inspired process exploiting reversible photoenol activation with a polymerization initiator. Subsequently, macromolecules are grown from the functionalized areas and the spatially coded glass slides are characterized by atomic-force microscopy. Our approach allows lines with a full-width-at-half-maximum of down to 60 nm and line gratings with a lateral resolution of 100 nm to be written, both surpassing the diffraction limit.

  10. Nanoscale resolution for fluorescence microscopy via adiabatic passage

    CERN Document Server

    Rubio, Juan Luis; Ahufinger, Verònica; Mompart, Jordi

    2015-01-01

    We propose the use of the subwavelength localization via adiabatic passage technique for fluorescence microscopy with nanoscale resolution in the far field. This technique uses a {\\Lambda}-type medium coherently coupled to two laser pulses: the pump, with a node in its spatial profile, and the Stokes. The population of the {\\Lambda} system is adiabatically transferred from one ground state to the other except at the node position, yielding a narrow population peak. This coherent localization allows fluorescence imaging with nanometer lateral resolution. We derive an analytical expression to asses the resolution and perform a comparison with the coherent population trapping and the stimulated-emission-depletion techniques.

  11. Effect of greenhouse gas emissions on stratospheric ozone depletion

    NARCIS (Netherlands)

    Velders GJM; LLO

    1997-01-01

    The depletion of the ozone layer is caused mainly by the increase in emissions of chlorine- and bromine-containing compounds like CFCs, halons, carbon tetrachloride, methyl chloroform and methyl bromide. Emissions of greenhouse gases can affect the depletion of the ozone layer through atmospheric i

  12. Effect of greenhouse gas emissions on stratospheric ozone depletion

    NARCIS (Netherlands)

    Velders GJM; LLO

    1997-01-01

    The depletion of the ozone layer is caused mainly by the increase in emissions of chlorine- and bromine-containing compounds like CFCs, halons, carbon tetrachloride, methyl chloroform and methyl bromide. Emissions of greenhouse gases can affect the depletion of the ozone layer through atmospheric

  13. Grueneisen relaxation photoacoustic microscopy

    Science.gov (United States)

    Wang, Lidai; Zhang, Chi; Wang, Lihong V.

    2014-01-01

    The temperature-dependent property of the Grueneisen parameter has been employed in photoacoustic imaging mainly to measure tissue temperature. Here we explore this property using a different approach and develop Grueneisen-relaxation photoacoustic microscopy (GR-PAM), a technique that images non-radiative absorption with confocal optical resolution. GR-PAM sequentially delivers two identical laser pulses with a micro-second-scale time delay. The first laser pulse generates a photoacoustic signal and thermally tags the in-focus absorbers. Owing to the temperature dependence of the Grueneisen parameter, when the second laser pulse excites the tagged absorbers within the thermal relaxation time, a photoacoustic signal stronger than the first one is produced. GR-PAM detects the amplitude difference between the two co-located photoacoustic signals, confocally imaging the non-radiative absorption. We greatly improved axial resolution from 45 µm to 2.3 µm and at the same time slightly improved lateral resolution from 0.63 µm to 0.41 µm. In addition, the optical sectioning capability facilitates the measurement of the absolute absorption coefficient without fluence calibration. PMID:25379919

  14. In vivo microscopy.

    Science.gov (United States)

    Peti-Peterdi, János

    2016-04-01

    This article summarizes the past, present, and future promise of multiphoton excitation fluorescence microscopy for intravital kidney imaging. During the past 15years, several high-power visual research approaches have been developed using multiphoton imaging to study the normal functions of the healthy, intact, living kidney, and the various molecular and cellular mechanisms of the development of kidney diseases. In this review, the main focus will be on intravital multiphoton imaging of the glomerulus, the structure and function of the glomerular filtration barrier, especially the podocyte. Examples will be given for the combination of two powerful research tools, in vivo multiphoton imaging and mouse genetics using commercially available whole animal models for the detailed characterization of glomerular cell types, their function and fate, and for the better understanding of the molecular mechanisms of glomerular pathologies. One of the new modalities of multiphoton imaging, serial imaging of the same glomerulus in the same animal over several days will be emphasized for its potential for further advancing the field of nephrology research.

  15. Ultrafast scanning tunneling microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Botkin, D.A. [California Univ., Berkeley, CA (United States). Dept. of Physics]|[Lawrence Berkeley Lab., CA (United States)

    1995-09-01

    I have developed an ultrafast scanning tunneling microscope (USTM) based on uniting stroboscopic methods of ultrafast optics and scanned probe microscopy to obtain nanometer spatial resolution and sub-picosecond temporal resolution. USTM increases the achievable time resolution of a STM by more than 6 orders of magnitude; this should enable exploration of mesoscopic and nanometer size systems on time scales corresponding to the period or decay of fundamental excitations. USTM consists of a photoconductive switch with subpicosecond response time in series with the tip of a STM. An optical pulse from a modelocked laser activates the switch to create a gate for the tunneling current, while a second laser pulse on the sample initiates a dynamic process which affects the tunneling current. By sending a large sequence of identical pulse pairs and measuring the average tunnel current as a function of the relative time delay between the pulses in each pair, one can map the time evolution of the surface process. USTM was used to measure the broadband response of the STM`s atomic size tunnel barrier in frequencies from tens to hundreds of GHz. The USTM signal amplitude decays linearly with the tunnel junction conductance, so the spatial resolution of the time-resolved signal is comparable to that of a conventional STM. Geometrical capacitance of the junction does not appear to play an important role in the measurement, but a capacitive effect intimately related to tunneling contributes to the measured signals and may limit the ultimate resolution of the USTM.

  16. Mueller polarimetric microscopy

    Science.gov (United States)

    Laude-Boulesteix, Blandine; De Martino, Antonello; Le Naour, Gilles; Genestie, Catherine; Schwartz, Laurent; Garcia-Caurel, Enric; Drevillon, Bernard

    2004-07-01

    We present a multispectral polarimetric imaging system well suited for complete Mueller matrix microscopy. The source is a spectrally filtered halogen light bulb, and the image is formed on a fast CCD camera The light polarization is modulated before the sample and analyzed after the sample by using nematic liquid crystal modulators.. The whole Mueller matrix image of the sample is typically measured over 5 seconds for a good signal-to-noise ratio. The instrument design, together with an original and easy-to-operate calibration procedure provides a high polarimetric accuracy over wide ranges of wavelengths and magnifications. Mueller polarimetry provides separate images of scalar and vector retardation and dichroism of the sample, together with its depolarizing power, while all these effects do contribute simultaneously to the contrasts observed in standard polarized microsopy. Polarimetric images of several samples, namely an unstained rabbit cornea, a picrosirius red stained hepatic biopsy, and a rat artery specifically stained for collagen III are shown and discussed

  17. Ozone Depletion Potential of CH3Br

    Science.gov (United States)

    Sander, Stanley P.; Ko, Malcolm K. W.; Sze, Nien Dak; Scott, Courtney; Rodriquez, Jose M.; Weisenstein, Debra K.

    1998-01-01

    The ozone depletion potential (ODP) of methyl bromide (CH3Br) can be determined by combining the model-calculated bromine efficiency factor (BEF) for CH3Br and its atmospheric lifetime. This paper examines how changes in several key kinetic data affect BEF. The key reactions highlighted in this study include the reaction of BrO + H02, the absorption cross section of HOBr, the absorption cross section and the photolysis products of BrON02, and the heterogeneous conversion of BrON02 to HOBR and HN03 on aerosol particles. By combining the calculated BEF with the latest estimate of 0.7 year for the atmospheric lifetime of CH3Br, the likely value of ODP for CH3Br is 0.39. The model-calculated concentration of HBr (approximately 0.3 pptv) in the lower stratosphere is substantially smaller than the reported measured value of about I pptv. Recent publications suggested models can reproduce the measured value if one assumes a yield for HBr from the reaction of BrO + OH or from the reaction of BrO + H02. Although the DeAlore et al. evaluation concluded any substantial yield of HBr from BrO + HO2 is unlikely, for completeness, we calculate the effects of these assumed yields on BEF for CH3Br. Our calculations show that the effects are minimal: practically no impact for an assumed 1.3% yield of HBr from BrO + OH and 10% smaller for an assumed 0.6% yield from BrO + H02.

  18. The Abiotic Depletion Potential: Background, Updates, and Future

    Directory of Open Access Journals (Sweden)

    Lauran van Oers

    2016-03-01

    Full Text Available Depletion of abiotic resources is a much disputed impact category in life cycle assessment (LCA. The reason is that the problem can be defined in different ways. Furthermore, within a specified problem definition, many choices can still be made regarding which parameters to include in the characterization model and which data to use. This article gives an overview of the problem definition and the choices that have been made when defining the abiotic depletion potentials (ADPs for a characterization model for abiotic resource depletion in LCA. Updates of the ADPs since 2002 are also briefly discussed. Finally, some possible new developments of the impact category of abiotic resource depletion are suggested, such as redefining the depletion problem as a dilution problem. This means taking the reserves in the environment and the economy into account in the reserve parameter and using leakage from the economy, instead of extraction rate, as a dilution parameter.

  19. Ozone depletion during solar proton events in solar cycle 21

    Science.gov (United States)

    Mcpeters, R. D.; Jackman, C. H.

    1985-01-01

    Ozone profile data from the Solar Backscattered Ultraviolet Instrument on Nimbus 7 from 1979 to the present and clear cases of ozone destruction associated with five sudden proton events (SPEs) on June 7, 1979, August 21, 1979, October 13-14, 1981, July 13, 1982, and December 8, 1982 are found. During the SPE on July 13, 1982, the largest of this solar cycle, no depletion at all at 45 km is observed, but there is a 15 percent ozone depletion at 50 km increasing to 27 percent at 55 km, all at a solar zenith angle of 85 deg. A strong variation of the observed depletion with solar zenith angle is found, with maximum depletion occurring at the largest zenith angles (near 85 deg) decreasing to near zero for angles below about 70 deg. The observed depletion is short lived, disappearing within hours of the end of the SPE.

  20. Analysis and Application of Whey Protein Depleted Skim Milk Systems

    DEFF Research Database (Denmark)

    Sørensen, Hanne

    homogenisation (UHPH). The microfiltration will result in a milk fraction more or less depleted from whey protein, and could probably in combination with UHPH treatment contribute to milk fractions and cheeses with novel micro and macrostructures. These novel fractions could be used as new ingredients to improve......-destructive methods for this purpose. A significant changed structure was observed in skim milk depleted or partly depleted for whey protein, acidified and UHPH treated. Some of the properties of the UHPH treated skim milk depleted from whey protein observed in this study support the idea, that UHPH treatment has...... this. LF-NMR relaxation were utilised to obtain information about the water mobility (relaxation time), in diluted skim milk systems depleted from whey protein. Obtained results indicate that measuring relaxation times with LF-NMR could be difficult to utilize, since no clear relationship between...

  1. Barium depletion study on impregnated cathodes and lifetime prediction

    Energy Technology Data Exchange (ETDEWEB)

    Roquais, J.M.; Poret, F.; Doze, R. le; Ricaud, J.L.; Monterrin, A.; Steinbrunn, A

    2003-06-15

    In the thermionic cathodes used in cathode ray-tubes (CRTs), barium is the key element for the electronic emission. In the case of the dispenser cathodes made of a porous tungsten pellet impregnated with Ba, Ca aluminates, the evaporation of Ba determines the cathode lifetime with respect to emission performance in the CRT. The Ba evaporation results in progressive depletion of the impregnating material inside the pellet. In the present work, the Ba depletion with time has been extensively characterized over a large range of cathode temperature. Calculations using the depletion data allowed modeling of the depletion as a function of key parameters. The link between measured depletion and emission in tubes has been established, from which an end-of-life criterion was deduced. Taking modeling into account, predicting accelerated life-tests were performed using high-density maximum emission current (MIK)

  2. The effect of ego depletion on sprint start reaction time.

    Science.gov (United States)

    Englert, Chris; Bertrams, Alex

    2014-10-01

    In the current study, we consider that optimal sprint start performance requires the self-control of responses. Therefore, start performance should depend on athletes' self-control strength. We assumed that momentary depletion of self-control strength (ego depletion) would either speed up or slow down the initiation of a sprint start, where an initiation that was sped up would carry the increased risk of a false start. Applying a mixed between- (depletion vs. nondepletion) and within- (before vs. after manipulation of depletion) subjects design, we tested the start reaction times of 37 sport students. We found that participants' start reaction times decelerated after finishing a depleting task, whereas it remained constant in the nondepletion condition. These results indicate that sprint start performance can be impaired by unrelated preceding actions that lower momentary self-control strength. We discuss practical implications in terms of optimizing sprint starts and related overall sprint performance.

  3. Magnetic Resonance Force Microscopy System

    Data.gov (United States)

    Federal Laboratory Consortium — The Magnetic Resonance Force Microscopy (MRFM) system, developed by ARL, is the world's most sensitive nuclear magnetic resonance (NMR) spectroscopic analysis tool,...

  4. NDE Acoustic Microscopy Research Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The purpose is to develop advanced, more effective high-resolution micro-NDE materials characterization methods using scanning acoustic microscopy. The laboratory's...

  5. Reversible chemical reactions for single-color multiplexing microscopy.

    Science.gov (United States)

    Brox, Dominik; Schwering, Michael; Engelhardt, Johann; Herten, Dirk-Peter

    2014-08-04

    Recent developments in biology demand an increasing number of simultaneously imaged structures with standard fluorescence microscopy. However, the number of multiplexed channels is limited for most multiplexing modalities, such as spectral multiplexing or fluorescence-lifetime imaging. We propose extending the number of imaging channels by using chemical reactions, controlling the emissive state of fluorescent dyes. As proof of concept, we reversibly switch a fluorescent copper sensor to enable successive imaging of two different structures in the same spectral channel. We also show that this chemical multiplexing is orthogonal to existing methods. By using two different dyes, we combine chemical with spectral multiplexing for the simultaneous imaging of four different structures with only two spectrally different channels. We characterize and discuss the approach and provide perspectives for extending imaging modalities in stimulated emission depletion microscopy, for which spectral multiplexing is technically demanding.

  6. Advanced computing in electron microscopy

    CERN Document Server

    Kirkland, Earl J

    2010-01-01

    This book features numerical computation of electron microscopy images as well as multislice methods High resolution CTEM and STEM image interpretation are included in the text This newly updated second edition will bring the reader up to date on new developments in the field since the 1990's The only book that specifically addresses computer simulation methods in electron microscopy

  7. Electronic Blending in Virtual Microscopy

    Science.gov (United States)

    Maybury, Terrence S.; Farah, Camile S.

    2010-01-01

    Virtual microscopy (VM) is a relatively new technology that transforms the computer into a microscope. In essence, VM allows for the scanning and transfer of glass slides from light microscopy technology to the digital environment of the computer. This transition is also a function of the change from print knowledge to electronic knowledge, or as…

  8. Associative Interactions in Crowded Solutions of Biopolymers Counteract Depletion Effects.

    Science.gov (United States)

    Groen, Joost; Foschepoth, David; te Brinke, Esra; Boersma, Arnold J; Imamura, Hiromi; Rivas, Germán; Heus, Hans A; Huck, Wilhelm T S

    2015-10-14

    The cytosol of Escherichia coli is an extremely crowded environment, containing high concentrations of biopolymers which occupy 20-30% of the available volume. Such conditions are expected to yield depletion forces, which strongly promote macromolecular complexation. However, crowded macromolecule solutions, like the cytosol, are very prone to nonspecific associative interactions that can potentially counteract depletion. It remains unclear how the cytosol balances these opposing interactions. We used a FRET-based probe to systematically study depletion in vitro in different crowded environments, including a cytosolic mimic, E. coli lysate. We also studied bundle formation of FtsZ protofilaments under identical crowded conditions as a probe for depletion interactions at much larger overlap volumes of the probe molecule. The FRET probe showed a more compact conformation in synthetic crowding agents, suggesting strong depletion interactions. However, depletion was completely negated in cell lysate and other protein crowding agents, where the FRET probe even occupied slightly more volume. In contrast, bundle formation of FtsZ protofilaments proceeded as readily in E. coli lysate and other protein solutions as in synthetic crowding agents. Our experimental results and model suggest that, in crowded biopolymer solutions, associative interactions counterbalance depletion forces for small macromolecules. Furthermore, the net effects of macromolecular crowding will be dependent on both the size of the macromolecule and its associative interactions with the crowded background.

  9. 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.

  10. Molybdenum depletion around P-phases Ni-Cr-Mo-W weld metals; Empobrecimento de molibdenio ao redor da fase P em metais de solda de ligas Ni-Cr-Mo-W

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Cleiton Carvalho; Miranda, Helio Cordeiro de; Farias, Jesualdo Pereira [Universidade Federal do Ceara (UFC), CE (Brazil). Departamento de Engenharia Metalurgica e de Materiais; Afonso, Conrado Ramos Moreira; Ramirez, Antonio Jose [Laboratorioo Nacional de Luz Sincroton (LNLS), SP (Brazil)

    2010-07-01

    This work evaluated the local chemical composition in matrix/precipitate interface in a Ni-Cr-Mo-W alloy weld metals deposited on substrate of C-Mn steel. The microstructural characterization was carried out through optical microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). The results had shown that the presence of secondary phases precipitates in the interdendritic region. Through SEM analysis were observed indications of depletion of Mo around these phases. These precipitates were identified as P-phase by TEM analysis. The Mo depletion indications were confirmed through EDS. The Mo depletion was a result of a reheating due to several welding heat cycles deposited to promote the coating layer. (author)

  11. Caveolae Depletion Contributes to Vasorelaxant Effects of Chenodeoxycholic Acid

    Directory of Open Access Journals (Sweden)

    Zhongchao Wang

    2017-06-01

    Full Text Available Background/Aims: High concentration of bile acids (BAs induces hydrophobicity-dependent vasorelaxtant effects with hydrophobic BAs showing greater responses than hydrophilic BAs, of which the underlying mechanisms are still unclear. Caveolae are invaginations on membranes of endothelial cells (ECs entraping endothelial nitric oxide synthase (eNOS to prevent its activation, which plays a critical role in regulation of vascular function. The purpose of the present study was to investigate the role of caveolae in vasorelaxant effects of BAs. Methods: Chenodeoxycholic acid (CDCA and cholic acid (CA were used to represent hydrophobic and hydrophilic BA, respectively. Vascular responses of abdominal aorta were measured by isometric force recording. Morphology of caveolae was examined by transmission electron microscopy. Protein expression of total eNOS (t-eNOS or phosphorylated eNOS (p-eNOS was determined by Western blot. Nitric oxide (NO content was observed by fluorometric assay. Results: We demonstrated that CDCA as well as Methyl-β-cyclodextrin (MCD, a commonly used reagent for cholesterol depletion, reduced potassium chloride (KCl- or phenylephrine (PE-elicited vasoconstriction (P < 0.05, and enhanced acetylcholine (Ach-elicited vasodilatation (P < 0.05 in endothelium-intact abdominal aorta but not in endothelium-denuded or CA-treated vessels. CDCA and MCD, but not CA significantly disrupted caveolae structure on ECs of abdominal aorta which was recovered by cholesterol incubation (P < 0.05. Protein expression of t-eNOS was significantly decreased (P < 0.05, and that of p-eNOS together with NO content was significantly increased in CDCA- and MCD- but not CA-treated vessels (P < 0.05 as compared with vehicle. The effect was reversed by either endothelium-denudation or cholesterol replenishment. Moreover, with cholesterol incubation, no significant differences were found in vascular responses among CDCA-, CA- or vehicle-treated vessels. Conclusion

  12. Super-resolution Microscopy Reveals Compartmentalization of Peroxisomal Membrane Proteins.

    Science.gov (United States)

    Galiani, Silvia; Waithe, Dominic; Reglinski, Katharina; Cruz-Zaragoza, Luis Daniel; Garcia, Esther; Clausen, Mathias P; Schliebs, Wolfgang; Erdmann, Ralf; Eggeling, Christian

    2016-08-12

    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 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. Moreover, imported protein sterol carrier protein 2 (SCP2) occupies only a subregion of larger peroxisomes, highlighting the heterogeneous distribution of proteins even within the peroxisome. Finally, our data reveal subpopulations of peroxisomes showing only weak colocalization between PEX14 and PEX5 or PEX11 but at the same time a clear compartmentalized organization. This compartmentalization, which was less evident in cases of strong colocalization, indicates dynamic protein reorganization linked to changes occurring in the peroxisomes. Through the use of multicolor stimulated emission depletion microscopy, we have been able to characterize peroxisomes and their constituents to a yet unseen level of detail while maintaining a highly statistical approach, paving the way for equally complex biological studies in the future.

  13. Tracking the stochastic fate of cells of the renin lineage after podocyte depletion using multicolor reporters and intravital imaging.

    Science.gov (United States)

    Kaverina, Natalya V; Kadoya, Hiroyuki; Eng, Diana G; Rusiniak, Michael E; Sequeira-Lopez, Maria Luisa S; Gomez, R Ariel; Pippin, Jeffrey W; Gross, Kenneth W; Peti-Peterdi, Janos; Shankland, Stuart J

    2017-01-01

    Podocyte depletion plays a major role in focal segmental glomerular sclerosis (FSGS). Because cells of the renin lineage (CoRL) serve as adult podocyte and parietal epithelial cell (PEC) progenitor candidates, we generated Ren1cCre/R26R-ConfettiTG/WT and Ren1dCre/R26R-ConfettiTG/WT mice to determine CoRL clonality during podocyte replacement. Four CoRL reporters (GFP, YFP, RFP, CFP) were restricted to cells in the juxtaglomerular compartment (JGC) at baseline. Following abrupt podocyte depletion in experimental FSGS, all four CoRL reporters were detected in a subset of glomeruli at day 28, where they co-expressed de novo four podocyte proteins (podocin, nephrin, WT-1 and p57) and two glomerular parietal epithelial cell (PEC) proteins (claudin-1, PAX8). To monitor the precise migration of a subset of CoRL over a 2w period following podocyte depletion, intravital multiphoton microscopy was used. Our findings demonstrate direct visual support for the migration of single CoRL from the JGC to the parietal Bowman's capsule, early proximal tubule, mesangium and glomerular tuft. In summary, these results suggest that following podocyte depletion, multi-clonal CoRL migrate to the glomerulus and replace podocyte and PECs in experimental FSGS.

  14. Microscopy techniques in flavivirus research.

    Science.gov (United States)

    Chong, Mun Keat; Chua, Anthony Jin Shun; Tan, Terence Tze Tong; Tan, Suat Hoon; Ng, Mah Lee

    2014-04-01

    The Flavivirus genus is composed of many medically important viruses that cause high morbidity and mortality, which include Dengue and West Nile viruses. Various molecular and biochemical techniques have been developed in the endeavour to study flaviviruses. However, microscopy techniques still have irreplaceable roles in the identification of novel virus pathogens and characterization of morphological changes in virus-infected cells. Fluorescence microscopy contributes greatly in understanding the fundamental viral protein localizations and virus-host protein interactions during infection. Electron microscopy remains the gold standard for visualizing ultra-structural features of virus particles and infected cells. New imaging techniques and combinatory applications are continuously being developed to push the limit of resolution and extract more quantitative data. Currently, correlative live cell imaging and high resolution three-dimensional imaging have already been achieved through the tandem use of optical and electron microscopy in analyzing biological specimens. Microscopy techniques are also used to measure protein binding affinities and determine the mobility pattern of proteins in cells. This chapter will consolidate on the applications of various well-established microscopy techniques in flavivirus research, and discuss how recently developed microscopy techniques can potentially help advance our understanding in these membrane viruses.

  15. Soil microstructure and electron microscopy

    Science.gov (United States)

    Smart, P.; Fryer, J. R.

    1988-01-01

    As part of the process of comparing Martian soils with terrestial soils, high resolution electron microscopy and associated techniques should be used to examine the finer soil particles, and various techniques of electron and optical microscopy should be used to examine the undisturbed structure of Martian soils. To examine the structure of fine grained portions of the soil, transmission electron microscopy may be required. A striking feature of many Martian soils is their red color. Although the present-day Martian climate appears to be cold, this color is reminiscent of terrestial tropical red clays. Their chemical contents are broadly similar.

  16. AFSC/REFM: Pacific cod Localized Depletion Study

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data from Localized Depletion study for Pacific cod 2001-2005. Study was conducted using cod pot gear to measure localized abundance of Pacific cod inside and...

  17. Groundwater depletion in the United States (1900-2008)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A natural consequence of groundwater withdrawals is the removal of water from subsurface storage, but the overall rates and magnitude of groundwater depletion in the...

  18. Prediction Method of Safety Mud Density in Depleted Oilfields

    Directory of Open Access Journals (Sweden)

    Yuan Jun-Liang

    2013-04-01

    Full Text Available At present, many oilfields were placed in the middle and late development period and the reservoir pressure depleted usually, resulting in more serious differential pressure sticking and drilling mud leakage both in the reservoir and cap rock. In view of this situation, a systematic prediction method of safety mud density in depleted oilfields was established. The influence of reservoir depletion on stress and strength in reservoir and cap formation were both studied and taken into the prediction of safety mud density. The research showed that the risk of differential pressure sticking and drilling mud leakage in reservoir and cap formation were both increased and they were the main prevention object in depleted oilfields drilling. The research results were used to guide the practice drilling work, the whole progress gone smoothly.

  19. STRATOSPHERIC OZONE DEPLETION: A FOCUS ON EPA'S RESEARCH

    Science.gov (United States)

    In September of 1987 the United States, along with 26 other countries, signed a landmark treaty to limit and subsequently, through revisions, phase out the production of all significant ozone depleting substances. Many researchers suspected that these chemicals, especially chl...

  20. Depletion of microglia exacerbates postischemic inflammation and brain injury

    National Research Council Canada - National Science Library

    Jin, Wei-Na; Shi, Samuel Xiang-Yu; Li, Zhiguo; Li, Minshu; Wood, Kristofer; Gonzales, Rayna J; Liu, Qiang

    2017-01-01

    ...). Although depletion of microglia has been linked to worse stroke outcomes, it remains unclear to what extent and by what mechanisms activated microglia influence ischemia-induced inflammation and injury in the brain...

  1. Asymmetric spindle pole formation in CPAP-depleted mitotic cells.

    Science.gov (United States)

    Lee, Miseon; Chang, Jaerak; Chang, Sunghoe; Lee, Kyung S; Rhee, Kunsoo

    2014-02-21

    CPAP is an essential component for centriole formation. Here, we report that CPAP is also critical for symmetric spindle pole formation during mitosis. We observed that pericentriolar material between the mitotic spindle poles were asymmetrically distributed in CPAP-depleted cells even with intact numbers of centrioles. The length of procentrioles was slightly reduced by CPAP depletion, but the length of mother centrioles was not affected. Surprisingly, the young mother centrioles of the CPAP-depleted cells are not fully matured, as evidenced by the absence of distal and subdistal appendage proteins. We propose that the selective absence of centriolar appendages at the young mother centrioles may be responsible for asymmetric spindle pole formation in CPAP-depleted cells. Our results suggest that the neural stem cells with CPAP mutations might form asymmetric spindle poles, which results in premature initiation of differentiation.

  2. Individual differences in dopamine level modulate the ego depletion effect.

    Science.gov (United States)

    Dang, Junhua; Xiao, Shanshan; Liu, Ying; Jiang, Yumeng; Mao, Lihua

    2016-01-01

    Initial exertion of self-control impairs subsequent self-regulatory performance, which is referred to as the ego depletion effect. The current study examined how individual differences in dopamine level, as indexed by eye blink rate (EBR), would moderate ego depletion. An inverted-U-shaped relationship between EBR and subsequent self-regulatory performance was found when participants initially engaged in self-control but such relationship was absent in the control condition where there was no initial exertion, suggesting individuals with a medium dopamine level may be protected from the typical ego depletion effect. These findings are consistent with a cognitive explanation which considers ego depletion as a phenomenon similar to "switch costs" that would be neutralized by factors promoting flexible switching.

  3. Net depletion determination for Hankin Wetland Development Project

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This memorandum contains the analysis and the data used to produce the net depletion that would occur as a result of the Hankin Wetland Development Project.

  4. Adding trend data to Depletion-Based Stock Reduction Analysis

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Bayesian model of Depletion-Based Stock Reduction Analysis (DB-SRA), informed by a time series of abundance indexes, was developed, using the Sampling Importance...

  5. Hydroxide depletion in dilute supernates stored in waste tanks

    Energy Technology Data Exchange (ETDEWEB)

    Hobbs, D.T.

    1985-10-10

    Free hydroxide ion in dilute supernates are depleted by reaction with atmospheric carbon dioxide to form bicarbonate and carbonate species and by reaction with acidic compounds formed by the radiolytic decomposition of tetraphenylborate salts. A model of the kinetics and thermodynamics of absorption of carbon dioxide in the waste tanks has been developed. Forecasts of the rate of hydroxide depletion and the requirements for sodium hydroxide to maintain technical standards have been made for the washed sludge and washed precipitate storage tanks. Hydroxide depletion is predicted to have a minimal impact on sludge processing operations. However, in-tank precipitation and downstream DWPF operations are predicted to be significantly affected by hydroxide depletion in Tank 49H. The installation of a carbon dioxide scrubber on Tank 49H may be justified in view of the decrease in alkali content and variation in the melter feed.

  6. Conditional depletion of nuclear proteins by the Anchor Away system.

    Science.gov (United States)

    Fan, Xiaochun; Geisberg, Joseph V; Wong, Koon Ho; Jin, Yi

    2011-01-01

    Nuclear proteins play key roles in the regulation of many important cellular processes. In Saccharomyces cerevisiae, many genes encoding nuclear proteins are essential. This unit describes a method termed Anchor Away that can be used to conditionally and rapidly deplete nuclear proteins of interest. It involves conditional export of the protein of interest out of the nucleus and its subsequent sequestration in the cytoplasm. This method can be used to simultaneously deplete multiple proteins from the nucleus.

  7. Cholinergic depletion and basal forebrain volume in primary progressive aphasia

    Directory of Open Access Journals (Sweden)

    Jolien Schaeverbeke

    2017-01-01

    In the PPA group, only LV cases showed decreases in AChE activity levels compared to controls. Surprisingly, a substantial number of SV cases showed significant AChE activity increases compared to controls. BF volume did not correlate with AChE activity levels in PPA. To conclude, in our sample of PPA patients, LV but not SV was associated with cholinergic depletion. BF atrophy in PPA does not imply cholinergic depletion.

  8. Inositol depletion restores vesicle transport in yeast phospholipid flippase mutants.

    Science.gov (United States)

    Yamagami, Kanako; Yamamoto, Takaharu; Sakai, Shota; Mioka, Tetsuo; Sano, Takamitsu; Igarashi, Yasuyuki; Tanaka, Kazuma

    2015-01-01

    In eukaryotic cells, type 4 P-type ATPases function as phospholipid flippases, which translocate phospholipids from the exoplasmic leaflet to the cytoplasmic leaflet of the lipid bilayer. Flippases function in the formation of transport vesicles, but the mechanism remains unknown. Here, we isolate an arrestin-related trafficking adaptor, ART5, as a multicopy suppressor of the growth and endocytic recycling defects of flippase mutants in budding yeast. Consistent with a previous report that Art5p downregulates the inositol transporter Itr1p by endocytosis, we found that flippase mutations were also suppressed by the disruption of ITR1, as well as by depletion of inositol from the culture medium. Interestingly, inositol depletion suppressed the defects in all five flippase mutants. Inositol depletion also partially restored the formation of secretory vesicles in a flippase mutant. Inositol depletion caused changes in lipid composition, including a decrease in phosphatidylinositol and an increase in phosphatidylserine. A reduction in phosphatidylinositol levels caused by partially depleting the phosphatidylinositol synthase Pis1p also suppressed a flippase mutation. These results suggest that inositol depletion changes the lipid composition of the endosomal/TGN membranes, which results in vesicle formation from these membranes in the absence of flippases.

  9. The Optimal Depletion of Exhaustible Resource under Different Commitment

    Institute of Scientific and Technical Information of China (English)

    Zhou Wei; Wu Kangping

    2012-01-01

    There are few papers in the literature focusing on the issue of the optimal depletion of exhaustible resources in the framework of variable time preference. This paper attempts to analyze the pure consumption of exhaustible resource under hy- perbolic time preference, and to discuss the optimal depletion rate and the effect of the protection of the exhaustible resource under different commitment abilities. The results of model show that the case of the hyperbolic discount with the full commitment of the govemment is equivalent to the case of constant discount of the social planner problem. In that case, the optimal depletion rate and the initial consumption of exhaustible resource are the slowest. On the contrary, they are the highest and the myopic behaviors lead to excessive consumption of exhaustible resources inevitably without commitment. Otherwise, in the case of partial commit- ment, the results are between the cases of full commitment and of no commitment. Therefore, with the hyperbolic time preference, the optimal depletion rate of resource depends on the commitment ability. Higher commitment ability leads to lower effective rate of time preference, and consequently, lower depletion rate and lower initial depletion value. The improvement of commitment ability can decrease the impatience and myopia behaviors, and contribute to the protection of the exhaustible resources.

  10. Changes in local surface structure and Sr depletion in Fe-implanted SrTiO3 (001)

    Science.gov (United States)

    Lobacheva, O.; Yiu, Y. M.; Chen, N.; Sham, T. K.; Goncharova, L. V.

    2017-01-01

    Local surface structure of single crystal strontium titanate SrTiO3 (001) samples implanted with Fe in the range of concentrations between 2 × 1014 to 2 × 1016 Fe/cm2 at 30 keV has been investigated. In order to facilitate Fe substitution (doping), implanted samples were annealed in oxygen at 350 °C. Sr depletion was observed from the near-surface layers impacted by the ion-implantation process, as revealed by Rutherford Backscattering Spectrometry (RBS), X-ray photoelectron spectroscopy (XPS), X-ray Absorption Near Edge Spectroscopy (XANES), and Atomic Force Microscopy (AFM). Hydrocarbon contaminations on the surface may contribute to the mechanisms of Sr depletion, which have important implications for Sr(Ti1-xFex)O3-δ materials in gas sensing applications.

  11. 77 FR 53236 - Proposed International Isotopes Fluorine Extraction Process and Depleted Uranium Deconversion...

    Science.gov (United States)

    2012-08-31

    ... COMMISSION Proposed International Isotopes Fluorine Extraction Process and Depleted Uranium Deconversion... International Isotopes Fluorine Extraction Process and Depleted Uranium Deconversion Plant (INIS) in Lea County... construction, operation, and decommissioning of a fluorine extraction and depleted uranium...

  12. Single-cell time-lapse analysis of depletion of the universally conserved essential protein YgjD

    Directory of Open Access Journals (Sweden)

    Ackermann Martin

    2011-05-01

    Full Text Available Abstract Background The essential Escherichia coli gene ygjD belongs to a universally conserved group of genes whose function has been the focus of a number of recent studies. Here, we put ygjD under control of an inducible promoter, and used time-lapse microscopy and single cell analysis to investigate the phenotypic consequences of the depletion of YgjD protein from growing cells. Results We show that loss of YgjD leads to a marked decrease in cell size and termination of cell division. The transition towards smaller size occurs in a controlled manner: cell elongation and cell division remain coupled, but cell size at division decreases. We also find evidence that depletion of YgjD leads to the synthesis of the intracellular signaling molecule (pppGpp, inducing a cellular reaction resembling the stringent response. Concomitant deletion of the relA and spoT genes - leading to a strain that is uncapable of synthesizing (pppGpp - abrogates the decrease in cell size, but does not prevent termination of cell division upon YgjD depletion. Conclusions Depletion of YgjD protein from growing cells leads to a decrease in cell size that is contingent on (pppGpp, and to a termination of cell division. The combination of single-cell timelapse microscopy and statistical analysis can give detailed insights into the phenotypic consequences of the loss of essential genes, and can thus serve as a new tool to study the function of essential genes.

  13. A comparative analysis of the morphology and evolution of permanent sperm depletion in spiders.

    Directory of Open Access Journals (Sweden)

    Peter Michalik

    Full Text Available Once thought to be energetically cheap and easy to produce, empirical work has shown that sperm is a costly and limited resource for males. In some spider species, there is behavioral evidence that sperm are permanently depleted after a single mating. This extreme degree of mating investment appears to co-occur with other reproductive strategies common to spiders, e.g. genital mutilation and sexual cannibalism. Here we corroborate that sperm depletion in the golden orb-web spider Nephila clavipes is permanent by uncovering its mechanistic basis using light and electron microscopy. In addition, we use a phylogeny-based statistical analysis to test the evolutionary relationships between permanent sperm depletion (PSD and other reproductive strategies in spiders. Male testes do not produce sperm during adulthood, which is unusual in spiders. Instead, spermatogenesis is nearly synchronous and ends before the maturation molt. Testis size decreases as males approach their maturation molt and reaches its lowest point after sperm is transferred into the male copulatory organs (pedipalps. As a consequence, the amount of sperm available to males for mating is limited to the sperm contained in the pedipalps, and once it is used, males lose their ability to fertilize eggs. Our data suggest that PSD has evolved independently at least three times within web-building spiders and is significantly correlated with the evolution of other mating strategies that limit males to monogamy, including genital mutilation and sexual cannibalism. We conclude that PSD may be an energy-saving adaptation in species where males are limited to monogamy. This could be particularly important in web-building spiders where extreme sexual size dimorphism results in large, sedentary females and small, searching males who rarely feed as adults and are vulnerable to starvation. Future work will explore possible energetic benefits and the evolutionary lability of PSD relative to other

  14. Unfolding DNA condensates produced by DNA-like charged depletants: A force spectroscopy study

    Science.gov (United States)

    Lima, C. H. M.; Rocha, M. S.; Ramos, E. B.

    2017-02-01

    In this work, we have measured, by means of optical tweezers, forces acting on depletion-induced DNA condensates due to the presence of the DNA-like charged protein bovine serum albumin (BSA). The stretching and unfolding measurements performed on the semi-flexible DNA chain reveal (1) the softening of the uncondensed DNA contour length and (2) a mechanical behavior strikingly different from those previously observed: the force-extension curves of BSA-induced DNA condensates lack the "saw-tooth" pattern and applied external forces as high as ≈80 pN are unable to fully unfold the condensed DNA contour length. This last mechanical experimental finding is in agreement with force-induced "unpacking" detailed Langevin dynamics simulations recently performed by Cortini et al. on model rod-like shaped condensates. Furthermore, a simple thermodynamics analysis of the unfolding process has enabled us to estimate the free energy involved in the DNA condensation: the estimated depletion-induced interactions vary linearly with both the condensed DNA contour length and the BSA concentration, in agreement with the analytical and numerical analysis performed on model DNA condensates. We hope that future additional experiments can decide whether the rod-like morphology is the actual one we are dealing with (e.g. pulling experiments coupled with super-resolution fluorescence microscopy).

  15. Mechanosensitive channel activity and F-actin organization in cholesterol-depleted human leukaemia cells.

    Science.gov (United States)

    Morachevskaya, Elena; Sudarikova, Anastasiya; Negulyaev, Yuri

    2007-04-01

    This study focuses on the functional role of cellular cholesterol in the regulation of mechanosensitive cation channels activated by stretch in human leukaemia K562 cells. The patch-clamp method was employed to examine the effect of methyl-beta-cyclodextrin (MbetaCD), a synthetic cholesterol-sequestering agent, on stretch-activated single currents. We found that cholesterol-depleting treatment with MbetaCD resulted in a suppression of the activity of mechanosensitive channels without a change in the unitary conductance. The probability that the channel was open significantly decreased after treatment with MbetaCD. Fluorescent microscopy revealed F-actin reorganization, possibly involving actin assembly, after incubation of the cells with MbetaCD. We suggest that suppression of mechanosensitive channel activation in cholesterol-depleted leukaemia cells is due to F-actin rearrangement, presumably induced by lipid raft destruction. Our observations are consistent with the notion that stretch-activated cation channels in eukaryotic cells are regulated by the membrane-cytoskeleton complex rather than by tension developed purely in the lipid bilayer.

  16. Depletion of insulin receptor substrate 2 reverses oncogenic transformation induced by v-src

    Institute of Scientific and Technical Information of China (English)

    Hong-zhi SUN; Lin XU; Bo ZHOU; Wei-jin ZANG; Shu-fang WU

    2011-01-01

    Aim: To investigate the role of insulin receptor substrate 2 (IRS-2) in oncogenic transformation induced by v-src. Methods: IRS-2 gene was silenced using small interfering RNAs (siRNAs). Nuclear translocation and interaction of IRS-2 with v-src was determined using subcellular fractionation, confocal microscopy, and immunoprecipitation. The activity of the cyclin D1 promoter and r-DNA promoter was measured with a luciferase assay.Results: Depletion of IRS-2 inhibited R-/v-src cell growth and reverse the oncogenic transformation. IRS-2 bound to src via its two PI3-K binding sites, which are critical for activities involved in the transformation. Nuclear IRS-2 occupied the cyclin D1 and rDNA promoters. The combination of IRS-2 and v-src increased the activity of the two promoters, especially the rDNA promoter.Conclusion: Depletion of insulin receptor substrate 2 could reverse oncogenic transformation induced by v-src.

  17. Microvascular Endothelial Dysfunction in Obesity Is Driven by Macrophage-Dependent Hydrogen Sulfide Depletion.

    Science.gov (United States)

    Candela, Joseph; Wang, Rui; White, Carl

    2017-05-01

    The function of perivascular adipose tissue as an anticontractile mediator in the microvasculature is lost during obesity. Obesity results in inflammation and recruitment of proinflammatory macrophages to the perivascular adipose tissue that is paralleled by depletion of the vasorelaxant signaling molecule hydrogen sulfide (H2S) in the vessel. The current objective was to assess the role of macrophages in determining vascular [H2S] and defining how this impinged on vasodilation. Contractility and [H2S] were measured in mesenteric resistance arterioles from lean and obese mice by using pressure myography and confocal microscopy, respectively. Vasodilation was impaired and smooth muscle and endothelial [H2S] decreased in vessels from obese mice compared with those from lean controls. Coculturing vessels from lean mice with macrophages from obese mice, or macrophage-conditioned media, recapitulated obese phenotypes in vessels. These effects were mediated by low molecular weight species and dependent on macrophage inducible nitric oxide synthase activity. The inducible nitric oxide synthase activity of perivascular adipose tissue-resident proinflammatory macrophages promotes microvascular endothelial dysfunction by reducing the bioavailability of H2S in the vessel. These findings support a model in which vascular H2S depletion underpins the loss of perivascular adipose tissue anticontractile function in obesity. © 2017 American Heart Association, Inc.

  18. A robust TEC depletion detector algorithm for satellite based navigation in Indian zone and depletion analysis for GAGAN

    Science.gov (United States)

    Dashora, Nirvikar

    2012-07-01

    Equatorial plasma bubble (EPB) and associated plasma irregularities are known to cause severe scintillation for the satellite signals and produce range errors, which eventually result either in loss of lock of the signal or in random fluctuation in TEC, respectively, affecting precise positioning and navigation solutions. The EPBs manifest as sudden reduction in line of sight TEC, which are more often called TEC depletions, and are spread over thousands of km in meridional direction and a few hundred km in zonal direction. They change shape and size while drifting from one longitude to another in nighttime ionosphere. For a satellite based navigation system, like GAGAN in India that depends upon (i) multiple satellites (i.e. GPS) (ii) multiple ground reference stations and (iii) a near real time data processing, such EPBs are of grave concern. A TEC model generally provides a near real-time grid based ionospheric vertical errors (GIVEs) over hypothetically spread 5x5 degree latitude-longitude grid points. But, on night when a TEC depletion occurs in a given longitude sector, it is almost impossible for any system to give a forecast of GIVEs. If loss-of-lock events occur due to scintillation, there is no way to improve the situation. But, when large and random depletions in TEC occur with scintillations and without loss-of-lock, it affects low latitude TEC in two ways. (a) Multiple satellites show depleted TEC which may be very different from model-TEC values and hence the GIVE would be incorrect over various grid points (ii) the user may be affected by depletions which are not sampled by reference stations and hence interpolated GIVE within one square would be grossly erroneous. The most general solution (and the far most difficult as well) is having advance knowledge of spatio-temporal occurrence and precise magnitude of such depletions. While forecasting TEC depletions in spatio-temporal domain are a scientific challenge (as we show below), operational systems

  19. Ego depletion decreases trust in economic decision making

    Science.gov (United States)

    Ainsworth, Sarah E.; Baumeister, Roy F.; Vohs, Kathleen D.; Ariely, Dan

    2014-01-01

    Three experiments tested the effects of ego depletion on economic decision making. Participants completed a task either requiring self-control or not. Then participants learned about the trust game, in which senders are given an initial allocation of $10 to split between themselves and another person, the receiver. The receiver receives triple the amount given and can send any, all, or none of the tripled money back to the sender. Participants were assigned the role of the sender and decided how to split the initial allocation. Giving less money, and therefore not trusting the receiver, is the safe, less risky response. Participants who had exerted self-control and were depleted gave the receiver less money than those in the non-depletion condition (Experiment 1). This effect was replicated and moderated in two additional experiments. Depletion again led to lower amounts given (less trust), but primarily among participants who were told they would never meet the receiver (Experiment 2) or who were given no information about how similar they were to the receiver (Experiment 3). Amounts given did not differ for depleted and non-depleted participants who either expected to meet the receiver (Experiment 2) or were led to believe that they were very similar to the receiver (Experiment 3). Decreased trust among depleted participants was strongest among neurotics. These results imply that self-control facilitates behavioral trust, especially when no other cues signal decreased social risk in trusting, such as if an actual or possible relationship with the receiver were suggested. PMID:25013237

  20. Hyperbolic Metamaterial Feasible for Fabrication with Direct Laser Writing Processes

    CERN Document Server

    Zhang, Xu; Güney, Durdu Ö

    2015-01-01

    Stimulated emission depletion microscopy inspired direct laser writing (STED-DLW) processes can offer diffraction-unlimited fabrication of 3D-structures, not possible with traditional electron-beam or optical lithography. We propose a hyperbolic metamaterial for fabrication with STED-DLW. First, we design meandering wire structures with three different magnetic dipoles which can be excited under different incidences of light. Then, based on effective parameters corresponding to normal incidence and lateral incidence, we find that the hyperbolic dispersion relation for five-layer structure appears between 15THz to 20THz. Finally, we investigate the influence of imaginary parts of the effective parameters on the metamaterial dispersion. The proposed metamaterial structure has also potential for three-dimensionally isotropic permeability despite geometric anisotropy.

  1. Superresolution and Fluorescence Dynamics Evidence Reveal That Intact Liposomes Do Not Cross the Human Skin Barrier

    DEFF Research Database (Denmark)

    Dreier, Jes; Sørensen, Jens A; Brewer, Jonathan R

    2016-01-01

    In this study we use the combination of super resolution optical microscopy and raster image correlation spectroscopy (RICS) to study the mechanism of action of liposomes as transdermal drug delivery systems in human skin. Two different compositions of liposomes were applied to newly excised human...... skin, a POPC liposome and a more flexible liposome containing the surfactant sodium cholate. Stimulated emission depletion microscopy (STED) images of intact skin and cryo-sections of skin treated with labeled liposomes were recorded displaying an optical resolution low enough to resolve the 100 nm...

  2. Optical far-field super-resolution microscopy using nitrogen vacancy center ensemble in bulk diamond

    OpenAIRE

    Li, Shen; Chen, Xiang-Dong; Zhao, Bo-Wen; Dong, Yang; Zou, Chong-Wen; Guo, Guang-Can; Sun, Fang-Wen

    2016-01-01

    We demonstrate an optical far-field super-resolution microscopy using array of nitrogen vacancy centers in bulk diamond as near-field optical probes. The local optical field, which transmits through the nanostructures on the diamond surface, is measured by detecting the charge state conversion of nitrogen vacancy center. And the locating of nitrogen vacancy center with spatial resolution of 6.1 nm is realized with the charge state depletion nanoscopy. The nanostructures on the surface of diam...

  3. Attempted Depletion of Passenger Leukocytes by Irradiation in Pigs

    Directory of Open Access Journals (Sweden)

    Hao-Chih Tai

    2011-01-01

    Full Text Available Allograft/xenograft rejection is associated with “passenger leukocyte” migration from the organ into recipient lymph nodes. In Study 1, we attempted to deplete leukocytes from potential kidney “donor” pigs, using two regimens of total body irradiation. A dose of 700 cGy was administered, followed by either 800 cGy (“low-dose” or 1,300 cGy (“high dose” with the kidneys shielded. Neither regimen was entirely successful in depleting all leukocytes, although remaining T and 8 cell numbers were negligible. Study 2 was aimed at providing an indication of whether near-complete depletion of leukocytes had any major impact on kidney allograft survival. In non-immunosuppressed recipient pigs, survival of a kidney from a donor that received high-dose irradiation was compared with that of a kidney taken from a non-irradiated donor. Kidney graft survival was 9 and 7 days, respectively, suggesting that depletion had little impact on graft survival. The lack of effect may have been related to (i inadequate depletion of passenger leukocytes, thus not preventing a direct T cell response, (ii the presence of dead or dying leukocytes (antigens, thus not preventing an indirect T cell response, or (iii constitutive expression of MHC class II and B7 molecules on the porcine vascular endothelium, activating recipient T cells.

  4. Examining depletion theories under conditions of within-task transfer.

    Science.gov (United States)

    Brewer, Gene A; Lau, Kevin K H; Wingert, Kimberly M; Ball, B Hunter; Blais, Chris

    2017-07-01

    In everyday life, mental fatigue can be detrimental across many domains including driving, learning, and working. Given the importance of understanding and accounting for the deleterious effects of mental fatigue on behavior, a growing body of literature has studied the role of motivational and executive control processes in mental fatigue. In typical laboratory paradigms, participants complete a task that places demand on these self-control processes and are later given a subsequent task. Generally speaking, decrements to subsequent task performance are taken as evidence that the initial task created mental fatigue through the continued engagement of motivational and executive functions. Several models have been developed to account for negative transfer resulting from this "ego depletion." In the current study, we provide a brief literature review, specify current theoretical approaches to ego-depletion, and report an empirical test of current models of depletion. Across 4 experiments we found minimal evidence for executive control depletion along with strong evidence for motivation mediated ego depletion. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  5. Bond rupture between colloidal particles with a depletion interaction

    Energy Technology Data Exchange (ETDEWEB)

    Whitaker, Kathryn A.; Furst, Eric M., E-mail: furst@udel.edu [Department of Chemical and Biomolecular Engineering and Center for Molecular and Engineering Thermodynamics, University of Delaware, Newark, Delaware 19716 (United States)

    2016-05-15

    The force required to break the bonds of a depletion gel is measured by dynamically loading pairs of colloidal particles suspended in a solution of a nonadsorbing polymer. Sterically stabilized poly(methyl methacrylate) colloids that are 2.7 μm diameter are brought into contact in a solvent mixture of cyclohexane-cyclohexyl bromide and polystyrene polymer depletant. The particle pairs are subject to a tensile load at a constant loading rate over many approach-retraction cycles. The stochastic nature of the thermal rupture events results in a distribution of bond rupture forces with an average magnitude and variance that increases with increasing depletant concentration. The measured force distribution is described by the flux of particle pairs sampling the energy barrier of the bond interaction potential based on the Asakura–Oosawa depletion model. A transition state model demonstrates the significance of lubrication hydrodynamic interactions and the effect of the applied loading rate on the rupture force of bonds in a depletion gel.

  6. Wall depletion length of a channel-confined polymer

    Science.gov (United States)

    Cheong, Guo Kang; Li, Xiaolan; Dorfman, Kevin D.

    2017-02-01

    Numerous experiments have taken advantage of DNA as a model system to test theories for a channel-confined polymer. A tacit assumption in analyzing these data is the existence of a well-defined depletion length characterizing DNA-wall interactions such that the experimental system (a polyelectrolyte in a channel with charged walls) can be mapped to the theoretical model (a neutral polymer with hard walls). We test this assumption using pruned-enriched Rosenbluth method (PERM) simulations of a DNA-like semiflexible polymer confined in a tube. The polymer-wall interactions are modeled by augmenting a hard wall interaction with an exponentially decaying, repulsive soft potential. The free energy, mean span, and variance in the mean span obtained in the presence of a soft wall potential are compared to equivalent simulations in the absence of the soft wall potential to determine the depletion length. We find that the mean span and variance about the mean span have the same depletion length for all soft potentials we tested. In contrast, the depletion length for the confinement free energy approaches that for the mean span only when depletion length no longer depends on channel size. The results have implications for the interpretation of DNA confinement experiments under low ionic strengths.

  7. Depletion of microglia exacerbates postischemic inflammation and brain injury.

    Science.gov (United States)

    Jin, Wei-Na; Shi, Samuel Xiang-Yu; Li, Zhiguo; Li, Minshu; Wood, Kristofer; Gonzales, Rayna J; Liu, Qiang

    2017-06-01

    Brain ischemia elicits microglial activation and microglia survival depend on signaling through colony-stimulating factor 1 receptor (CSF1R). Although depletion of microglia has been linked to worse stroke outcomes, it remains unclear to what extent and by what mechanisms activated microglia influence ischemia-induced inflammation and injury in the brain. Using a mouse model of transient focal cerebral ischemia and reperfusion, we demonstrated that depletion of microglia via administration of the dual CSF1R/c-Kit inhibitor PLX3397 exacerbates neurodeficits and brain infarction. Depletion of microglia augmented the production of inflammatory mediators, leukocyte infiltration, and cell death during brain ischemia. Of note, microglial depletion-induced exacerbation of stroke severity did not solely depend on lymphocytes and monocytes. Importantly, depletion of microglia dramatically augmented the production of inflammatory mediators by astrocytes after brain ischemia . In vitro studies reveal that microglia restricted ischemia-induced astrocyte response and provided neuroprotective effects. Our findings suggest that neuroprotective effects of microglia may result, in part, from its inhibitory action on astrocyte response after ischemia.

  8. The Physical Origin of Long Gas Depletion Times in Galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Semenov, Vadim [Chicago U., Astron. Astrophys. Ctr.; Kravtsov, Andrey [Chicago U., KICP; Gnedin, Nickolay [Fermilab

    2017-04-13

    We present a model that elucidates why gas depletion times in galaxies are long compared to the time scales of the processes driving the evolution of the interstellar medium. We show that global depletion times are not set by any "bottleneck" in the process of gas evolution towards the star-forming state. Instead, depletion times are long because star-forming gas converts only a small fraction of its mass into stars before it is dispersed by dynamical and feedback processes. Thus, complete depletion requires that gas transitions between star-forming and non-star-forming states multiple times. Our model does not rely on the assumption of equilibrium and can be used to interpret trends of depletion times with the properties of observed galaxies and the parameters of star formation and feedback recipes in galaxy simulations. In particular, the model explains the mechanism by which feedback self-regulates star formation rate in simulations and makes it insensitive to the local star formation efficiency. We illustrate our model using the results of an isolated $L_*$-sized disk galaxy simulation that reproduces the observed Kennicutt-Schmidt relation for both molecular and atomic gas. Interestingly, the relation for molecular gas is close to linear on kiloparsec scales, even though a non-linear relation is adopted in simulation cells. This difference is due to stellar feedback, which breaks the self-similar scaling of the gas density PDF with the average gas surface density.

  9. OZONE DEPLETING SUBSTANCES ELIMINATION MANAGEMENT: THE SUCCESS STORY OF MACEDONIA

    Directory of Open Access Journals (Sweden)

    Margarita Matlievska

    2013-04-01

    Full Text Available Man, with its activities, produces and uses substances that have negative impact on the environment and the human health, and can cause an economic damage. Consequently, they have a great impact on quality of life. Among the most harmful chemicals are Ozone Depleting Substances that are subject of regulation with international conventions. This Paper supports the fact that each country has to undertake national efforts for ozone depleting substances reduction and elimination. In that respect, the general objective of the Paper is to present the Macedonian unique experience regarding its efforts to reduce or eliminate these substances. The following two aspects were subject to the research: national legislation which regulates the Ozone Depleting Substances import and export as well as the implementation of the projects that resulted with the elimination of Ozone Depleting Substances quantities in the period 1995 – 2010. The research outcomes confirm the starting research hypothesis i.e. that with adequately created and implemented national action, the amount of Ozone Depleting Substances consumption can dramatically fall.

  10. Global Depletion of Groundwater Resources: Past and Future Analyses

    Science.gov (United States)

    Bierkens, M. F.; de Graaf, I. E. M.; Van Beek, L. P.; Wada, Y.

    2014-12-01

    Globally, about 17% of the crops are irrigated, yet irrigation accounts for 40% of the global food production. As more than 40% of irrigation water comes from groundwater, groundwater abstraction rates are large and exceed natural recharge rates in many regions of the world, thus leading to groundwater depletion. In this paper we provide an overview of recent research on global groundwater depletion. We start with presenting various estimates of global groundwater depletion, both from flux based as well as volume based methods. We also present estimates of the contribution of non-renewable groundwater to irrigation water consumption and how this contribution developed during the last 50 years. Next, using a flux based method, we provide projections of groundwater depletion for the coming century under various socio-economic and climate scenarios. As groundwater depletion contributes to sea-level rise, we also provide estimates of this contribution from the past as well as for future scenarios. Finally, we show recent results of groundwater level changes and change in river flow as a result of global groundwater abstractions as obtained from a global groundwater flow model.

  11. Recovery of the Ozone Layer: The Ozone Depleting Gas Index

    Science.gov (United States)

    Hofmann, David J.; Montzka, Stephen A.

    2009-01-01

    The stratospheric ozone layer, through absorption of solar ultraviolet radiation, protects all biological systems on Earth. In response to concerns over the depletion of the global ozone layer, the U.S. Clean Air Act as amended in 1990 mandates that NASA and NOAA monitor stratospheric ozone and ozone-depleting substances. This information is critical for assessing whether the Montreal Protocol on Substances That Deplete the Ozone Layer, an international treaty that entered into force in 1989 to protect the ozone layer, is having its intended effect of mitigating increases in harmful ultraviolet radiation. To provide the information necessary to satisfy this congressional mandate, both NASA and NOAA have instituted and maintained global monitoring programs to keep track of ozone-depleting gases as well as ozone itself. While data collected for the past 30 years have been used extensively in international assessments of ozone layer depletion science, the language of scientists often eludes the average citizen who has a considerable interest in the health of Earth's protective ultraviolet radiation shield. Are the ozone-destroying chemicals declining in the atmosphere? When will these chemicals decline to pre-ozone hole levels so that the Antarctic ozone hole might disappear? Will this timing be different in the stratosphere above midlatitudes?

  12. Self-regulatory depletion increases emotional reactivity in the amygdala.

    Science.gov (United States)

    Wagner, Dylan D; Heatherton, Todd F

    2013-04-01

    The ability to self-regulate can become impaired when people are required to engage in successive acts of effortful self-control, even when self-control occurs in different domains. Here, we used functional neuroimaging to test whether engaging in effortful inhibition in the cognitive domain would lead to putative dysfunction in the emotional domain. Forty-eight participants viewed images of emotional scenes during functional magnetic resonance imaging in two sessions that were separated by a challenging attention control task that required effortful inhibition (depletion group) or not (control group). Compared to the control group, depleted participants showed increased activity in the left amygdala to negative but not to positive or neutral scenes. Moreover, whereas the control group showed reduced amygdala activity to all scene types (i.e. habituation), the depletion group showed increased amygdala activity relative to their pre-depletion baseline; however this was only significant for negative scenes. Finally, depleted participants showed reduced functional connectivity between the left amygdala and ventromedial prefrontal cortex during negative scene processing. These findings demonstrate that consuming self-regulatory resources leads to an exaggerated neural response to emotional material that appears specific to negatively valenced stimuli and further suggests a failure to recruit top-down prefrontal regions involved in emotion regulation.

  13. Light microscopy - Methods and protocols

    Directory of Open Access Journals (Sweden)

    CarloAlberto Redi

    2011-11-01

    Full Text Available The first part of the book (six chapters is devoted to some selected applications of bright-field microscopy while the second part (eight chapters to some fluorescence microscopy studies. Both animal and plant biology investigations are presented covering multiple fields like immunology, cell signaling, cancer biology and, surprisingly to me, ecology. This chapter is titled: Light microscopy in aquatic ecology: Methods for plankton communities studies and it is due to Maria Carolina S. Soares and colleagues from the Laboratory of Aquatic Ecology, Dept. of Biology, Federal University of Juiz de Fora (Brazil. Here they present methods to quantify the different component of planktonic communities in a step-by-step manner so that virus, bacteria, algae and animals pertaining to different taxa can be recognized and the contribution they made to the plankton composition evaluated. It descends that even how the plankton composition is changing due to environmental variations can be accurately determined....

  14. Correlative fluorescence and electron microscopy.

    Science.gov (United States)

    Schirra, Randall T; Zhang, Peijun

    2014-10-01

    Correlative fluorescence and electron microscopy (CFEM) is a multimodal technique that combines dynamic and localization information from fluorescence methods with ultrastructural data from electron microscopy, to give new information about how cellular components change relative to the spatiotemporal dynamics within their environment. In this review, we will discuss some of the basic techniques and tools of the trade for utilizing this attractive research method, which is becoming a very powerful tool for biology labs. The information obtained from correlative methods has proven to be invaluable in creating consensus between the two types of microscopy, extending the capability of each, and cutting the time and expense associated with using each method separately for comparative analysis. The realization of the advantages of these methods in cell biology has led to rapid improvement in the protocols and has ushered in a new generation of instruments to reach the next level of correlation--integration.

  15. Correlative microscopy of detergent granules.

    Science.gov (United States)

    van Dalen, G; Nootenboom, P; Heussen, P C M

    2011-03-01

    The microstructure of detergent products for textile cleaning determines to a large extent the physical properties of these products. Correlative microscopy was used to reveal the microstructure by reconciling images obtained by scanning electron microscopy with energy dispersive X-ray analysis, X-ray microtomography and Fourier transform infrared microscopy. These techniques were applied on the same location of a subsample of a spray-dried detergent base powder embedded in polyacrylate. In this way, the three-dimensional internal and external structure of detergent granules could be investigated from milli to nano scale with detailed spatial information about the components present. This will generate knowledge how to design optimal microstructures for laundry products to obtain product properties demanded by the market. This method is also very useful for other powder systems used in a large variety of industries (e.g. for pharmaceutical, food, ceramic and metal industries).

  16. Confocal microscopy and exfoliative cytology.

    Science.gov (United States)

    Reddy, Shyam Prasad; Ramani, Pratibha; Nainani, Purshotam

    2013-05-01

    Early detection of potentially malignant lesions and invasive squamous-cell carcinoma in the oral cavity could be greatly improved through techniques that permit visualization of subtle cellular changes indicative of the neoplastic transformation process. One such technique is confocal microscopy. Combining rapidity with reliability, an innovative idea has been put forward using confocal microscope in exfoliative cytology. The main objective of this study was to assess confocal microscopy for cytological diagnosis and the results were compared with that of the standard PAP stain. Confocal microscope, acridine orange (AO) stain, PAP (Papanicolaou) stain. The study was designed to assess confocal microscopy for cytological diagnosis. In the process, smears of patients with (clinically diagnosed and/or suspected) oral squamous cell carcinoma as well as those of controls (normal people) were stained with acridine orange and observed under confocal microscope. The results were compared with those of the standard PAP method. Samples of buccal mucosa smears from normal patients and squamous cell carcinoma patients were made, fixed in 100% alcohol, followed by AO staining. The corresponding set of smears was stained with PAP stain using rapid PAP stain kit. The results obtained were compared with those obtained with AO confocal microscopy. The study had shown nuclear changes (malignant cells) in the smears of squamous cell carcinoma patients as increased intensity of fluorescence of the nucleus, when observed under confocal microscope. Acridine orange confocal microscopy showed good amount of sensitivity and specificity (93%) in identifying malignant cells in exfoliative cytological smears. Confocal microscopy was found to have good sensitivity in the identification of cancer (malignant) cells in exfoliative cytology, at par with the PAP method. The rapidity of processing and screening a specimen resulted in saving of time. It added a certain amount of objectivity to the

  17. Confocal microscopy and exfoliative cytology

    Directory of Open Access Journals (Sweden)

    Shyam Prasad Reddy

    2013-01-01

    Full Text Available Context: Early detection of potentially malignant lesions and invasive squamous-cell carcinoma in the oral cavity could be greatly improved through techniques that permit visualization of subtle cellular changes indicative of the neoplastic transformation process. One such technique is confocal microscopy. Combining rapidity with reliability, an innovative idea has been put forward using confocal microscope in exfoliative cytology. Aims: The main objective of this study was to assess confocal microscopy for cytological diagnosis and the results were compared with that of the standard PAP stain. Settings and Design: Confocal microscope, acridine orange (AO stain, PAP (Papanicolaou stain. The study was designed to assess confocal microscopy for cytological diagnosis. In the process, smears of patients with (clinically diagnosed and/or suspected oral squamous cell carcinoma as well as those of controls (normal people were stained with acridine orange and observed under confocal microscope. The results were compared with those of the standard PAP method. Materials and Methods: Samples of buccal mucosa smears from normal patients and squamous cell carcinoma patients were made, fixed in 100% alcohol, followed by AO staining. The corresponding set of smears was stained with PAP stain using rapid PAP stain kit. The results obtained were compared with those obtained with AO confocal microscopy. Results: The study had shown nuclear changes (malignant cells in the smears of squamous cell carcinoma patients as increased intensity of fluorescence of the nucleus, when observed under confocal microscope. Acridine orange confocal microscopy showed good amount of sensitivity and specificity (93% in identifying malignant cells in exfoliative cytological smears. Conclusion: Confocal microscopy was found to have good sensitivity in the identification of cancer (malignant cells in exfoliative cytology, at par with the PAP method. The rapidity of processing and

  18. Processable high internal phase Pickering emulsions using depletion attraction.

    Science.gov (United States)

    Kim, KyuHan; Kim, Subeen; Ryu, Jiheun; Jeon, Jiyoon; Jang, Se Gyu; Kim, Hyunjun; Gweon, Dae-Gab; Im, Won Bin; Han, Yosep; Kim, Hyunjung; Choi, Siyoung Q

    2017-02-01

    High internal phase emulsions have been widely used as templates for various porous materials, but special strategies are required to form, in particular, particle-covered ones that have been more difficult to obtain. Here, we report a versatile strategy to produce a stable high internal phase Pickering emulsion by exploiting a depletion interaction between an emulsion droplet and a particle using water-soluble polymers as a depletant. This attractive interaction facilitating the adsorption of particles onto the droplet interface and simultaneously suppressing desorption once adsorbed. This technique can be universally applied to nearly any kind of particle to stabilize an interface with the help of various non- or weakly adsorbing polymers as a depletant, which can be solidified to provide porous materials for many applications.

  19. Processable high internal phase Pickering emulsions using depletion attraction

    Science.gov (United States)

    Kim, Kyuhan; Kim, Subeen; Ryu, Jiheun; Jeon, Jiyoon; Jang, Se Gyu; Kim, Hyunjun; Gweon, Dae-Gab; Im, Won Bin; Han, Yosep; Kim, Hyunjung; Choi, Siyoung Q.

    2017-02-01

    High internal phase emulsions have been widely used as templates for various porous materials, but special strategies are required to form, in particular, particle-covered ones that have been more difficult to obtain. Here, we report a versatile strategy to produce a stable high internal phase Pickering emulsion by exploiting a depletion interaction between an emulsion droplet and a particle using water-soluble polymers as a depletant. This attractive interaction facilitating the adsorption of particles onto the droplet interface and simultaneously suppressing desorption once adsorbed. This technique can be universally applied to nearly any kind of particle to stabilize an interface with the help of various non- or weakly adsorbing polymers as a depletant, which can be solidified to provide porous materials for many applications.

  20. Observations of ozone depletion associated with solar proton events

    Science.gov (United States)

    Mcpeters, R. D.; Jackman, C. H.; Stassinopoulos, E. G.

    1981-01-01

    Ozone profiles from the solar proton events (SPE) of January and September 1971 and August 1972 were obtained after the backscattered ultraviolet (BUV) measured radiances were corrected for the direct effects of protons on the instrument. The SPE of August 1972 produced an ozone depletion of 15% at 42 km that persisted for one month in both northern and southern polar regions. This long recovery time indicates that NO(x) was produced in a quantity sufficient to alter the ozone chemistry. The two SPE in 1971 were of moderate size, but produced ozone depletions of 10-30% at 50 km with a 36 hour recovery time. This rapid recovery is consistent with the assumption that HO(x) is responsible for altering the ozone chemistry (Weeks et al., 1972). The magnitude of the observed depletion, however, exceeds that predicted by the chemical models.

  1. Processable high internal phase Pickering emulsions using depletion attraction

    Science.gov (United States)

    Kim, KyuHan; Kim, Subeen; Ryu, Jiheun; Jeon, Jiyoon; Jang, Se Gyu; Kim, Hyunjun; Gweon, Dae-Gab; Im, Won Bin; Han, Yosep; Kim, Hyunjung; Choi, Siyoung Q.

    2017-01-01

    High internal phase emulsions have been widely used as templates for various porous materials, but special strategies are required to form, in particular, particle-covered ones that have been more difficult to obtain. Here, we report a versatile strategy to produce a stable high internal phase Pickering emulsion by exploiting a depletion interaction between an emulsion droplet and a particle using water-soluble polymers as a depletant. This attractive interaction facilitating the adsorption of particles onto the droplet interface and simultaneously suppressing desorption once adsorbed. This technique can be universally applied to nearly any kind of particle to stabilize an interface with the help of various non- or weakly adsorbing polymers as a depletant, which can be solidified to provide porous materials for many applications. PMID:28145435

  2. Effect of Shim Arm Depletion in the NBSR

    Energy Technology Data Exchange (ETDEWEB)

    Hanson A. H.; Brown N.; Diamond, D.J.

    2013-02-22

    The cadmium shim arms in the NBSR undergo burnup during reactor operation and hence, require periodic replacement. Presently, the shim arms are replaced after every 25 cycles to guarantee they can maintain sufficient shutdown margin. Two prior reports document the expected change in the 113Cd distribution because of the shim arm depletion. One set of calculations was for the present high-enriched uranium fuel and the other for the low-enriched uranium fuel when it was in the COMP7 configuration (7 inch fuel length vs. the present 11 inch length). The depleted 113Cd distributions calculated for these cores were applied to the current design for an equilibrium low-enriched uranium core. This report details the predicted effects, if any, of shim arm depletion on the shim arm worth, the shutdown margin, power distributions and kinetics parameters.

  3. Resource depletion does not influence prospective memory in college students

    Science.gov (United States)

    Talley Shelton, Jill; Cahill, Michael J.; Mullet, Hillary G.; Scullin, Michael K.; Einstein, Gilles O.; McDaniel, Mark A.

    2013-01-01

    This paper reports an experiment designed to investigate the potential influence of prior acts of self-control on subsequent prospective memory performance. College undergraduates (n = 146) performed either a cognitively depleting initial task (e.g., mostly incongruent Stroop task) or a less resource-consuming version of that task (e.g., all congruent Stroop task). Subsequently, participants completed a prospective memory task that required attentionally demanding monitoring processes. The results demonstrated that prior acts of self-control do not impair the ability to execute a future intention in college-aged adults. We conceptually replicated these results in three additional depletion and prospective memory experiments. This research extends a growing number of studies demonstrating the boundary conditions of the resource depletion effect in cognitive tasks. PMID:24021851

  4. Depletion potential in colloidal mixtures of hard spheres and platelets.

    Science.gov (United States)

    Harnau, L; Dietrich, S

    2004-05-01

    The depletion potential between two hard spheres in a solvent of thin hard disclike platelets is investigated by using either the Derjaguin approximation or density functional theory. Particular attention is paid to the density dependence of the depletion potential. A second-order virial approximation is applied, which yields nearly exact results for the bulk properties of the hard-platelet fluid at densities two times smaller than the density of the isotropic fluid at isotropic-nematic phase coexistence. As the platelet density increases, the attractive primary minimum of the depletion potential deepens and an additional small repulsive barrier at larger sphere separations develops. Upon decreasing the ratio of the radius of the spheres and the platelets, the primary minimum diminishes and the position of the small repulsive barrier shifts to smaller values of the sphere separation.

  5. Transient Effects And Pump Depletion In Stimulated Raman Scattering

    Science.gov (United States)

    Carlsten, J. L.; Wenzel, R. G...; Druhl, K.

    1983-11-01

    Stimulated rotational Raman scattering in a 300-K multipass cell filled with para-H2 with a single-mode CO2-pumped laser is studied using a frequency-narrowed optical parametric oscillator (OPO) as a probe laser at the Stokes frequency for the So(0) transition. Amplification and pump depletion are examined as a function of incident pump energy. The pump depletion shows clear evidence of transient behavior. A theoretical treatment of transient stimulated Raman scattering, including effects of both pump depletion and medium saturation is presented. In a first approximation, diffraction effects are neglected, and only plane-wave interactions are considered. The theoretical results are compared to the experimental pulse shapes.

  6. Multiphoton Microscopy for Ophthalmic Imaging

    Directory of Open Access Journals (Sweden)

    Emily A. Gibson

    2011-01-01

    Full Text Available We review multiphoton microscopy (MPM including two-photon autofluorescence (2PAF, second harmonic generation (SHG, third harmonic generation (THG, fluorescence lifetime (FLIM, and coherent anti-Stokes Raman Scattering (CARS with relevance to clinical applications in ophthalmology. The different imaging modalities are discussed highlighting the particular strength that each has for functional tissue imaging. MPM is compared with current clinical ophthalmological imaging techniques such as reflectance confocal microscopy, optical coherence tomography, and fluorescence imaging. In addition, we discuss the future prospects for MPM in disease detection and clinical monitoring of disease progression, understanding fundamental disease mechanisms, and real-time monitoring of drug delivery.

  7. DHMI: dynamic holographic microscopy interface

    Science.gov (United States)

    He, Xuefei; Zheng, Yujie; Lee, Woei Ming

    2016-12-01

    Digital holographic microscopy (DHM) is a powerful in-vitro biological imaging tool. In this paper, we report a fully automated off-axis digital holographic microscopy system completed with a graphical user interface in the Matlab environment. The interface primarily includes Fourier domain processing, phase reconstruction, aberration compensation and autofocusing. A variety of imaging operations such as region of interest selection, de-noising mode (filtering and averaging), low frame rate imaging for immediate reconstruction and high frame rate imaging routine ( 27 fps) are implemented to facilitate ease of use.

  8. Auxin-inducible protein depletion system in fission yeast

    Directory of Open Access Journals (Sweden)

    Kakimoto Tatsuo

    2011-02-01

    Full Text Available Abstract Background Inducible inactivation of a protein is a powerful approach for analysis of its function within cells. Fission yeast is a useful model for studying the fundamental mechanisms such as chromosome maintenance and cell cycle. However, previously published strategies for protein-depletion are successful only for some proteins in some specific conditions and still do not achieve efficient depletion to cause acute phenotypes such as immediate cell cycle arrest. The aim of this work was to construct a useful and powerful protein-depletion system in Shizosaccaromyces pombe. Results We constructed an auxin-inducible degron (AID system, which utilizes auxin-dependent poly-ubiquitination of Aux/IAA proteins by SCFTIR1 in plants, in fission yeast. Although expression of a plant F-box protein, TIR1, decreased Mcm4-aid, a component of the MCM complex essential for DNA replication tagged with Aux/IAA peptide, depletion did not result in an evident growth defect. We successfully improved degradation efficiency of Mcm4-aid by fusion of TIR1 with fission yeast Skp1, a conserved F-box-interacting component of SCF (improved-AID system; i-AID, and the cells showed severe defect in growth. The i-AID system induced degradation of Mcm4-aid in the chromatin-bound MCM complex as well as those in soluble fractions. The i-AID system in conjunction with transcription repression (off-AID system, we achieved more efficient depletion of other proteins including Pol1 and Cdc45, causing early S phase arrest. Conclusion Improvement of the AID system allowed us to construct conditional null mutants of S. pombe. We propose that the off-AID system is the powerful method for in vivo protein-depletion in fission yeast.

  9. Plasma depletion layer: Magnetosheath flow structure and forces

    Directory of Open Access Journals (Sweden)

    Y. L. Wang

    2004-03-01

    Full Text Available The plasma depletion layer (PDL is a layer on the sunward side of the magnetopause with lower plasma density and higher magnetic field compared to the corresponding upstream magnetosheath values. In a previous study, we have validated the UCLA global (MHD model in studying the formation of the PDL by comparing model results, using spacecraft solar wind observations as the driver, with in situ PDL observations. In this study, we extend our previous work and examine the detailed MHD forces responsible for the PDL formation. We argue that MHD models, instead of gasdynamic models, should be used to study the PDL, because gasdynamic models cannot produce the PDL on the sunward side of the magnetopause. For northward (IMF, flux tube depletion occurs in almost all the subsolar magnetosheath. However, the streamlines closest to the magnetopause and the stagnation line show the greatest depletion. The relative strength of the various MHD forces changes along these streamlines. Forces along a flux tube at different stages of its depletion in the magnetosheath are analyzed. We find that a strong plasma pressure gradient force along the magnetic field at the bow shock and a pressure gradient force along the flux tube within the magnetosheath usually exist pushing plasma away from the equatorial plane to deplete the flux tube. More complex force structures along the flux tube are found close to the magnetopause. This new, more detailed description of flux tube depletion is compared with the results of Zwan and Wolf (1976 and differences are found. Near the magnetopause, the pressure gradient force along the flux tube either drives plasma away from the equatorial plane or pushes plasma toward the equatorial plane. As a result, a slow mode structure is seen along the flux tube which might be responsible for the observed two-layered slow mode structures.

    Key words. Magnetospheric physics (magnetosheath; solar wind-magnetosphere interactions. Space

  10. NUMERICAL SIMULATION FOR FORMED PROJECTILE OF DEPLETED URANIUM ALLOY

    Institute of Scientific and Technical Information of China (English)

    宋顺成; 高平; 才鸿年

    2003-01-01

    The numerical simulation for forming projectile of depleted uranium alloy with the SPH ( Smooth Particle Hydrodynamic ) algorithm was presented. In the computations the artificial pressures of detonation were used, i. e. , the spatial distribution and time distribution were given artificially. To describe the deformed behaviors of the depleted uranium alloy under high pressure and high strain rate, the Johnson-Cook model of materials was introduced. From the numerical simulation the formed projectile velocity,projectile geometry and the minimum of the height of detonation are obtained.

  11. Depletion zone calculation of MAPS detectors using TCAD simulations

    CERN Document Server

    Khan, Hira

    2013-01-01

    The volume of the depleted region of the collecting diode plays a vital role in the charge collection when an ionization particle traverses the Monolithic Active Pixel Sensor (MAPS) detector. Thus the volume of the depletion region should be large enough to collect majority electron-hole pairs generated by the ionization particle otherwise they will diffuse and eventually will take longer time for them to be collected. This report is about simulating a collecting diode (sector 4) with increased resistivity, in TCAD. After that comparing the results with the results of a low resistive collecting diode.

  12. UV radiation below an Arctic vortex with severe ozone depletion

    Directory of Open Access Journals (Sweden)

    B. M. Knudsen

    2005-01-01

    Full Text Available The erythemally weighted (UV irradiance below the severely depleted Arctic vortices in spring 1996 and 1997 were substantially elevated. On average the UV increased 36 and 33% relative to the 1979-1981 mean assuming clear skies from day 80-100 in 1996 and 1997, respectively. On clear sky days large regions of the Arctic experienced maximum UV increases exceeding 70 and 50% on single days in 1996 and 1997, respectively. A minor fraction of these increases are not anthropogenic and have a dynamical origin as seen by comparison to 1982, when hardly any ozone depletion is expected.

  13. Towards a complete propagation uncertainties in depletion calculations

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, J.S. [Universidad Politecnica de Madrid (Spain). Dept. of Nuclear Engineering; Gesellschaft fuer Anlagen- und Reaktorsicherheit mbH (GRS), Garching (Germany); Zwermann, W.; Gallner, L.; Puente-Espel, Federico; Velkov, K.; Hannstein, V. [Gesellschaft fuer Anlagen- und Reaktorsicherheit mbH (GRS), Garching (Germany); Cabellos, O. [Universidad Politecnica de Madrid (Spain). Dept. of Nuclear Engineering

    2013-07-01

    Propagation of nuclear data uncertainties to calculated values is interesting for design purposes and libraries evaluation. XSUSA, developed at GRS, propagates cross section uncertainties to nuclear calculations. In depletion simulations, fission yields and decay data are also involved and are a possible source of uncertainty that should be taken into account. We have developed tools to generate varied fission yields and decay libraries and to propagate uncertainties through depletion in order to complete the XSUSA uncertainty assessment capabilities. A generic test to probe the methodology is defined and discussed. (orig.)

  14. ROLE OF NUCLEONIC FERMI SURFACE DEPLETION IN NEUTRON STAR COOLING

    Energy Technology Data Exchange (ETDEWEB)

    Dong, J. M.; Zuo, W. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Lombardo, U. [Universita di Catania and Laboratori Nazionali del Sud (INFN), Catania I-95123 (Italy); Zhang, H. F. [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China)

    2016-01-20

    The Fermi surface depletion of beta-stable nuclear matter is calculated to study its effects on several physical properties that determine the neutron star (NS) thermal evolution. The neutron and proton Z factors measuring the corresponding Fermi surface depletions are calculated within the Brueckner–Hartree–Fock approach, employing the AV18 two-body force supplemented by a microscopic three-body force. Neutrino emissivity, heat capacity, and in particular neutron {sup 3}PF{sub 2} superfluidity, turn out to be reduced, especially at high baryonic density, to such an extent that the cooling rates of young NSs are significantly slowed.

  15. Summer time Fe depletion in the Antarctic mesopause region

    Science.gov (United States)

    Viehl, T. P.; Höffner, J.; Lübken, F.-J.; Plane, J. M. C.; Kaifler, B.; Morris, R. J.

    2015-05-01

    We report common volume measurements of Fe densities, temperatures and ice particle occurrence in the mesopause region at Davis Station, Antarctica (69°S) in the years 2011-2012. Our observations show a strong correlation of the Fe-layer summer time depletion with temperature, but no clear causal relation with the onset or occurrence of ice particles measured as noctilucent clouds (NLC) or polar mesosphere summer echoes (PMSE). The combination of these measurements indicates that the strong summer depletion can be explained by gas-phase chemistry alone and does not require heterogeneous removal of Fe and its compounds on ice particles.

  16. High Resolution Scanning Ion Microscopy

    NARCIS (Netherlands)

    Castaldo, V.

    2011-01-01

    The structure of the thesis is the following. The first chapter is an introduction to scanning microscopy, where the path that led to the Focused Ion Beam (FIB) is described and the main differences between electrons and ion beams are highlighted. Chapter 2 is what is normally referred to (which I d

  17. Four-dimensional electron microscopy.

    Science.gov (United States)

    Zewail, Ahmed H

    2010-04-09

    The discovery of the electron over a century ago and the realization of its dual character have given birth to one of the two most powerful imaging instruments: the electron microscope. The electron microscope's ability to resolve three-dimensional (3D) structures on the atomic scale is continuing to affect different fields, including materials science and biology. In this Review, we highlight recent developments and inventions made by introducing the fourth dimension of time in electron microscopy. Today, ultrafast electron microscopy (4D UEM) enables a resolution that is 10 orders of magnitude better than that of conventional microscopes, which are limited by the video-camera rate of recording. After presenting the central concept involved, that of single-electron stroboscopic imaging, we discuss prototypical applications, which include the visualization of complex structures when unfolding on different length and time scales. The developed UEM variant techniques are several, and here we illucidate convergent-beam and near-field imaging, as well as tomography and scanning-pulse microscopy. We conclude with current explorations in imaging of nanomaterials and biostructures and an outlook on possible future directions in space-time, 4D electron microscopy.

  18. Electron Microscopy of Intracellular Protozoa.

    Science.gov (United States)

    1983-08-01

    described by Casero et al.(1). For electron microscopy, 50 x 106 organisms in 5 ml of incubation medium (1) were treated with 10 0 DMSO(control cultures... Casero , R.A., Klayman, D.L., Childs, G.E., Scoville, J.P., and Desjardins, R.E. 1980. Activity of 2-acetylpyridine thiosemicarbazones against

  19. [History of microscopy in Spain].

    Science.gov (United States)

    Fernández-Galiano, D

    1994-12-01

    Nowadays, many Spanish research centers have excellent electronic microscopy services. The current situation, however, should not allow us to forget that the initial steps of microscopy in Spain were very difficult. The construction of excellent optical microscopies in the late XIX century, and their almost immediate introduction in Spain, coincides with a period of thriving scientific activity in our country. Both micrography and histology saw the highlights of their development in Spain, with scientists such as Ramón y Cajal, Río Hortega, Ferrán, Simarro, among others, all of them widely known at present. This article evokes briefly the vicissitudes of Spanish microscopy, from its very beginning in 1843, when the Allgemeine Anatomie by Jacob Henle was translated into Spanish, to present. Scientific historical facts in this article are often accompanied with anecdotes, which show the human aspect of those great scientists. The persevering task carried out by researchers whose names have been recorded in the history of Spanish science and technology, have established the grounds in which our current development is based.

  20. 3D -Ray Diffraction Microscopy

    DEFF Research Database (Denmark)

    Poulsen, Henning Friis; Schmidt, Søren; Juul Jensen, Dorte

    2014-01-01

    Three-dimensional X-ray diffraction (3DXRD) microscopy is a fast and non-destructive structural characterization technique aimed at the study of individual crystalline elements (grains or subgrains) within mm-sized polycrystalline specimens. It is based on two principles: the use of highly penetr...

  1. Mechanics in Steels through Microscopy

    NARCIS (Netherlands)

    Tirumalasetty, G.K.

    2013-01-01

    The goal of the study consolidated in this thesis is to understand the mechanics in steels using microscopy. In particular, the mechanical response of Transformation Induced Plasticity (TRIP) steels is correlated with their microstructures. Chapter 1 introduces the current state of the art of TRIP s

  2. Re-scan confocal microscopy

    NARCIS (Netherlands)

    De Luca, G.M.R.

    2016-01-01

    One of the instruments that gave insight in the morphology and function of cellular components is the optical microscope. Nowadays, optical microscopy in biomedical applications is commonly combined with fluorescence. One fundamental limit in the possibility to distinguish small structures in the sa

  3. Quantitative super-resolution microscopy

    NARCIS (Netherlands)

    Harkes, Rolf

    2016-01-01

    Super-Resolution Microscopy is an optical fluorescence technique. In this thesis we focus on single molecule super-resolution, where the position of single molecules is determined. Typically these molecules can be localized with a 10 to 30nm precision. This technique is applied in four different s

  4. Mechanics in Steels through Microscopy

    NARCIS (Netherlands)

    Tirumalasetty, G.K.

    2013-01-01

    The goal of the study consolidated in this thesis is to understand the mechanics in steels using microscopy. In particular, the mechanical response of Transformation Induced Plasticity (TRIP) steels is correlated with their microstructures. Chapter 1 introduces the current state of the art of TRIP

  5. 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 microsc...

  6. Near-field Optical Microscopy

    NARCIS (Netherlands)

    Ruiter, A.G.T.

    1997-01-01

    Near-field scanning optical microscopy (NSOM) is one of the most recent scanning probe techniques. In this technique, an optical probe is brought in the vicinity of the sample surface, in the near-field zone. The microscope can either work in illumination mode, in which the probe consists of a

  7. Contrast enhancement in light microscopy.

    Science.gov (United States)

    Ernst Keller, H; Watkins, Simon

    2013-01-01

    The optical microscope is a fundamental component of an image cytometry system. This unit covers the basic concepts of light microscopy, including Köhler illumination, resolution, contrast, and numerical aperture, and reviews the many types of instruments and techniques for contrast enhancement.

  8. Near-field Optical Microscopy

    NARCIS (Netherlands)

    Ruiter, Anthonius Gerardus Theodorus

    1997-01-01

    Near-field scanning optical microscopy (NSOM) is one of the most recent scanning probe techniques. In this technique, an optical probe is brought in the vicinity of the sample surface, in the near-field zone. The microscope can either work in illumination mode, in which the probe consists of a sub-w

  9. Super Resolution Fluorescence Microscopy and Tracking of Bacterial Flotillin (Reggie Paralogs Provide Evidence for Defined-Sized Protein Microdomains within the Bacterial Membrane but Absence of Clusters Containing Detergent-Resistant Proteins.

    Directory of Open Access Journals (Sweden)

    Felix Dempwolff

    2016-06-01

    Full Text Available Biological membranes have been proposed to contain microdomains of a specific lipid composition, in which distinct groups of proteins are clustered. Flotillin-like proteins are conserved between pro-and eukaryotes, play an important function in several eukaryotic and bacterial cells, and define in vertebrates a type of so-called detergent-resistant microdomains. Using STED microscopy, we show that two bacterial flotillins, FloA and FloT, form defined assemblies with an average diameter of 85 to 110 nm in the model bacterium Bacillus subtilis. Interestingly, flotillin microdomains are of similar size in eukaryotic cells. The soluble domains of FloA form higher order oligomers of up to several hundred kDa in vitro, showing that like eukaryotic flotillins, bacterial assemblies are based in part on their ability to self-oligomerize. However, B. subtilis paralogs show significantly different diffusion rates, and consequently do not colocalize into a common microdomain. Dual colour time lapse experiments of flotillins together with other detergent-resistant proteins in bacteria show that proteins colocalize for no longer than a few hundred milliseconds, and do not move together. Our data reveal that the bacterial membrane contains defined-sized protein domains rather than functional microdomains dependent on flotillins. Based on their distinct dynamics, FloA and FloT confer spatially distinguishable activities, but do not serve as molecular scaffolds.

  10. Super Resolution Fluorescence Microscopy and Tracking of Bacterial Flotillin (Reggie) Paralogs Provide Evidence for Defined-Sized Protein Microdomains within the Bacterial Membrane but Absence of Clusters Containing Detergent-Resistant Proteins

    Science.gov (United States)

    Dempwolff, Felix; Schmidt, Felix K.; Hervás, Ana B.; Stroh, Alex; Rösch, Thomas C.; Riese, Cornelius N.; Dersch, Simon; Heimerl, Thomas; Lucena, Daniella; Hülsbusch, Nikola; Stuermer, Claudia A. O.; Takeshita, Norio; Fischer, Reinhard; Graumann, Peter L.

    2016-01-01

    Biological membranes have been proposed to contain microdomains of a specific lipid composition, in which distinct groups of proteins are clustered. Flotillin-like proteins are conserved between pro—and eukaryotes, play an important function in several eukaryotic and bacterial cells, and define in vertebrates a type of so-called detergent-resistant microdomains. Using STED microscopy, we show that two bacterial flotillins, FloA and FloT, form defined assemblies with an average diameter of 85 to 110 nm in the model bacterium Bacillus subtilis. Interestingly, flotillin microdomains are of similar size in eukaryotic cells. The soluble domains of FloA form higher order oligomers of up to several hundred kDa in vitro, showing that like eukaryotic flotillins, bacterial assemblies are based in part on their ability to self-oligomerize. However, B. subtilis paralogs show significantly different diffusion rates, and consequently do not colocalize into a common microdomain. Dual colour time lapse experiments of flotillins together with other detergent-resistant proteins in bacteria show that proteins colocalize for no longer than a few hundred milliseconds, and do not move together. Our data reveal that the bacterial membrane contains defined-sized protein domains rather than functional microdomains dependent on flotillins. Based on their distinct dynamics, FloA and FloT confer spatially distinguishable activities, but do not serve as molecular scaffolds. PMID:27362352

  11. Super Resolution Fluorescence Microscopy and Tracking of Bacterial Flotillin (Reggie) Paralogs Provide Evidence for Defined-Sized Protein Microdomains within the Bacterial Membrane but Absence of Clusters Containing Detergent-Resistant Proteins.

    Science.gov (United States)

    Dempwolff, Felix; Schmidt, Felix K; Hervás, Ana B; Stroh, Alex; Rösch, Thomas C; Riese, Cornelius N; Dersch, Simon; Heimerl, Thomas; Lucena, Daniella; Hülsbusch, Nikola; Stuermer, Claudia A O; Takeshita, Norio; Fischer, Reinhard; Eckhardt, Bruno; Graumann, Peter L

    2016-06-01

    Biological membranes have been proposed to contain microdomains of a specific lipid composition, in which distinct groups of proteins are clustered. Flotillin-like proteins are conserved between pro-and eukaryotes, play an important function in several eukaryotic and bacterial cells, and define in vertebrates a type of so-called detergent-resistant microdomains. Using STED microscopy, we show that two bacterial flotillins, FloA and FloT, form defined assemblies with an average diameter of 85 to 110 nm in the model bacterium Bacillus subtilis. Interestingly, flotillin microdomains are of similar size in eukaryotic cells. The soluble domains of FloA form higher order oligomers of up to several hundred kDa in vitro, showing that like eukaryotic flotillins, bacterial assemblies are based in part on their ability to self-oligomerize. However, B. subtilis paralogs show significantly different diffusion rates, and consequently do not colocalize into a common microdomain. Dual colour time lapse experiments of flotillins together with other detergent-resistant proteins in bacteria show that proteins colocalize for no longer than a few hundred milliseconds, and do not move together. Our data reveal that the bacterial membrane contains defined-sized protein domains rather than functional microdomains dependent on flotillins. Based on their distinct dynamics, FloA and FloT confer spatially distinguishable activities, but do not serve as molecular scaffolds.

  12. Turning Microscopy in the Medical Curriculum Digital

    DEFF Research Database (Denmark)

    Vainer, Ben; Mortensen, Niels Werner; Poulsen, Steen Seier

    2017-01-01

    an administrative, an economic, and a teaching perspective. This fully automatic digital microscopy system has been received positively by both teachers and students, and a decision was made to convert all courses involving microscopy to the virtual microscopy format. As a result, conventional analog microscopy...

  13. Super-Resolution Scanning Laser Microscopy Based on Virtually Structured Detection.

    Science.gov (United States)

    Zhi, Yanan; Wang, Benquan; Yao, Xincheng

    2015-01-01

    Light microscopy plays a key role in biological studies and medical diagnosis. The spatial resolution of conventional optical microscopes is limited to approximately half the wavelength of the illumination light as a result of the diffraction limit. Several approaches-including confocal microscopy, stimulated emission depletion microscopy, stochastic optical reconstruction microscopy, photoactivated localization microscopy, and structured illumination microscopy-have been established to achieve super-resolution imaging. However, none of these methods is suitable for the super-resolution ophthalmoscopy of retinal structures because of laser safety issues and inevitable eye movements. We recently experimentally validated virtually structured detection (VSD) as an alternative strategy to extend the diffraction limit. Without the complexity of structured illumination, VSD provides an easy, low-cost, and phase artifact-free strategy to achieve super-resolution in scanning laser microscopy. In this article we summarize the basic principles of the VSD method, review our demonstrated single-point and line-scan super-resolution systems, and discuss both technical challenges and the potential of VSD-based instrumentation for super-resolution ophthalmoscopy of the retina.

  14. Microporous, demineralized collagen matrices in intact radicular dentin created by commonly used calcium-depleting endodontic irrigants.

    Science.gov (United States)

    Tay, Franklin R; Gutmann, James L; Pashley, David H

    2007-09-01

    The use of calcium-depleting solutions in restorative dentistry results in demineralization of intact coronal dentin beneath smear layers. Likewise, application of calcium-depleting irrigants as final rinses might create demineralized collagen matrices in intact radicular dentin after removal of root canal wall smear layers created during canal shaping. These unsupported collagen matrices collapse on desiccation and might be difficult to detect in scanning electron microscopy dehydration techniques traditionally used in endodontic research. Demineralized collagen matrices were identified, by using a hexamethyldisilazane dehydration protocol, on the surface of smear layer-depleted radicular dentin when NaOCl was used as initial rinse, followed by the use of 17% ethylenediaminetetraacetic acid or BioPure MTAD as the final rinse. Compaction of conventional root filling materials over a demineralized collagen matrix in instrumented dentin is analogous to performing the same procedure against the predentin collagen network in the uninstrumented parts of root canals. The potential consequences of this process are, however, unknown.

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

    DEFF Research Database (Denmark)

    Galiani, Silvia; Waithe, Dominic; Reglinski, Katharina

    2016-01-01

    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...... 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....... Moreover, imported protein sterol carrier protein 2 (SCP2) occupies only a subregion of larger peroxisomes, highlighting the heterogeneous distribution of proteins even within the peroxisome. Finally, our data reveal subpopulations of peroxisomes showing only weak colocalization between PEX14 and PEX5...

  16. 5.0. Depletion, activation, and spent fuel source terms

    Energy Technology Data Exchange (ETDEWEB)

    Wieselquist, William A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-04-01

    SCALE’s general depletion, activation, and spent fuel source terms analysis capabilities are enabled through a family of modules related to the main ORIGEN depletion/irradiation/decay solver. The nuclide tracking in ORIGEN is based on the principle of explicitly modeling all available nuclides and transitions in the current fundamental nuclear data for decay and neutron-induced transmutation and relies on fundamental cross section and decay data in ENDF/B VII. Cross section data for materials and reaction processes not available in ENDF/B-VII are obtained from the JEFF-3.0/A special purpose European activation library containing 774 materials and 23 reaction channels with 12,617 neutron-induced reactions below 20 MeV. Resonance cross section corrections in the resolved and unresolved range are performed using a continuous-energy treatment by data modules in SCALE. All nuclear decay data, fission product yields, and gamma-ray emission data are developed from ENDF/B-VII.1 evaluations. Decay data include all ground and metastable state nuclides with half-lives greater than 1 millisecond. Using these data sources, ORIGEN currently tracks 174 actinides, 1149 fission products, and 974 activation products. The purpose of this chapter is to describe the stand-alone capabilities and underlying methodology of ORIGEN—as opposed to the integrated depletion capability it provides in all coupled neutron transport/depletion sequences in SCALE, as described in other chapters.

  17. Identifying water mass depletion in Northern Iraq observed by GRACE

    Directory of Open Access Journals (Sweden)

    G. Mulder

    2014-10-01

    Full Text Available Observations acquired by Gravity Recovery And Climate Experiment (GRACE mission indicate a mass loss of 31 ± 3 km3 or 130 ± 14 mm in Northern Iraq between 2007 and 2009. This data is used as an independent validation of a hydrologic model of the region including lake mass variations. We developed a rainfall–runoff model for five tributaries of the Tigris River, based on local geology and climate conditions. Model inputs are precipitation from Tropical Rainfall Measurement Mission (TRMM observations, and potential evaporation from GLDAS model parameters. Our model includes a representation of the karstified aquifers that cause large natural groundwater variations in this region. Observed river discharges were used to calibrate our model. In order to get the total mass variations, we corrected for lake mass variations derived from Moderate Resolution Imaging Spectroradiometer (MODIS in combination with satellite altimetry and some in-situ data. Our rainfall–runoff model confirms that Northern Iraq suffered a drought between 2007 and 2009 and is consistent with the mass loss observed by GRACE over that period. Also, GRACE observed the annual cycle predicted by the rainfall–runoff model. The total mass depletion seen by GRACE between 2007 and 2009 is mainly explained by a lake mass depletion of 74 ± 4 mm and a natural groundwater depletion of 37 ± 6 mm. Our findings indicate that man-made groundwater extraction has a minor influence in this region while depletion of lake mass and geology play a key role.

  18. CD20(+) B Cell Depletion Alters T Cell Homing

    NARCIS (Netherlands)

    Kap, Yolanda S.; van Driel, Nikki; Laman, Jon D.; Tak, Paul P.; 't Hart, Bert A.

    2014-01-01

    Depleting mAbs against the pan B cell marker CD20 are remarkably effective in the treatment of autoimmune-mediated inflammatory disorders, but the underlying mechanisms are poorly defined. The primary objective of this study was to find a mechanistic explanation for the remarkable clinical effect of

  19. Gain depletion of X-ray framing camera

    Science.gov (United States)

    Koga, M.; Shiraga, H.

    2017-08-01

    X-ray imaging is very useful to investigate imploded core plasma in inertial fusion experiments. We can obtain information from X-ray images, such as shape, density, and temperature. An X-ray framing camera (XFC) capable of taking two-dimensional, time-resolved X-ray images is used to capture the images. In previous work, we developed a numerical model of an XFC to analyze its X-ray image. The calculated results agreed qualitatively with experimental results. However, it was not accurate enough to determine the absolute value of the signal. We thought this discrepancy was caused by gain depletion. In high energy laser experiments, high photon flux may cause gain depletion. This is a problem for accurate X-ray measurement. In this paper, we report our new model, including gain depletion. The new model is evaluated by tabletop laser experiments and high energy laser experiments. The results calculated using the new model agree quantitatively with our experimental results. Furthermore, we confirmed that gain depletion occurs in our high energy laser experiments. For quantitatively accurate X-ray intensity measurements, the XFC should be used with limited incident photon flux such that the gain linearity is guaranteed.

  20. Depletion of mitochondria in mammalian cells through enforced mitophagy.

    Science.gov (United States)

    Correia-Melo, Clara; Ichim, Gabriel; Tait, Stephen W G; Passos, João F

    2017-01-01

    Mitochondria are not only the 'powerhouse' of the cell; they are also involved in a multitude of processes that include calcium storage, the cell cycle and cell death. Traditional means of investigating mitochondrial importance in a given cellular process have centered upon depletion of mtDNA through chemical or genetic means. Although these methods severely disrupt the mitochondrial electron transport chain, mtDNA-depleted cells still maintain mitochondria and many mitochondrial functions. Here we describe a straightforward protocol to generate mammalian cell populations with low to nondetectable levels of mitochondria. Ectopic expression of the ubiquitin E3 ligase Parkin, combined with short-term mitochondrial uncoupler treatment, stimulates widespread mitophagy and effectively eliminates mitochondria. In this protocol, we explain how to generate Parkin-expressing, mitochondria-depleted cells from scratch in 23 d, as well as offer a variety of methods for confirming mitochondrial clearance. Furthermore, we describe culture conditions to maintain mitochondrial-depleted cells for up to 30 d with minimal loss of viability, for longitudinal studies. This method should prove useful for investigating the importance of mitochondria in a variety of biological processes.

  1. Ozone depletion and skin cancer incidence: an integrated modelling approach

    NARCIS (Netherlands)

    Slaper H; den Elzen MGJ; de Woerd HJ; de Greef J

    1992-01-01

    A decrease in stratospheric ozone, probably caused by chlorofluorocarbon (CFC) emissions, has been observed over large parts of the globe. The incidence of skin cancer is expected to increase due to ozone depletion. An integrated source-risk model is developed and applied to evaluate the increased

  2. Associative Interactions in Crowded Solutions of Biopolymers Counteract Depletion Effects

    NARCIS (Netherlands)

    Groen, Joost; Foschepoth, David; te Brinke, Esra; Boersma, Arnold J; Imamura, Hiromi; Rivas, Germán; Heus, Hans A; Huck, Wilhelm T S

    2015-01-01

    The cytosol of Escherichia coli is an extremely crowded environment, containing high concentrations of biopolymers which occupy 20-30% of the available volume. Such conditions are expected to yield depletion forces, which strongly promote macromolecular complexation. However, crowded macromolecule s

  3. Ozone depletion and skin cancer incidence: an integrated modelling approach

    NARCIS (Netherlands)

    Slaper H; den Elzen MGJ; de Woerd HJ; de Greef J

    1992-01-01

    A decrease in stratospheric ozone, probably caused by chlorofluorocarbon (CFC) emissions, has been observed over large parts of the globe. The incidence of skin cancer is expected to increase due to ozone depletion. An integrated source-risk model is developed and applied to evaluate the increased

  4. Vitamin D depletion aggravates hypertension and target-organ damage

    DEFF Research Database (Denmark)

    Andersen, Louise Bjørkholt; Przybyl, Lukasz; Haase, Nadine

    2015-01-01

    BACKGROUND: We tested the controversial hypothesis that vitamin D depletion aggravates hypertension and target-organ damage by influencing renin. METHODS AND RESULTS: Four-week-old double-transgenic rats (dTGR) with excess angiotensin (Ang) II production due to overexpression of the human renin (h......REN) and angiotensinogen (hAGT) genes received vitamin D-depleted (n=18) or standard chow (n=15) for 3 weeks. The depleted group had very low serum 25-hydroxyvitamin D levels (mean±SEM; 3.8±0.29 versus 40.6±1.19 nmol/L) and had higher mean systolic BP at week 5 (158±3.5 versus 134.6±3.7 mm Hg, P....6±3.3 versus 162.3±3.8 mm Hg, PVitamin D depletion led to increased relative heart weights and increased serum creatinine concentrations. Furthermore, the mRNAs of natriuretic peptides, neutrophil gelatinase-associated lipocalin, hREN, and r...

  5. Phosphatidylcholine mobility in bile salt depleted rat liver microsomes

    NARCIS (Netherlands)

    Oliveira Filgueiras, O.M. de; Defize, B.; Echteld, C.J.A. van; Bosch, H. van den

    1980-01-01

    Rat liver microsomes prepared by differential centrifugation are known to contain measurable levels of bile salts. More than 90% of these can be removed by passing the microsomal preparation through a Bio-Gel A-150m column. Bile salt depleted microsomes show a high level (> 95%) of mannose-6-phospha

  6. Spearfishing to depletion: evidence from temperate reef fishes in Chile.

    Science.gov (United States)

    Godoy, Natalio; Gelcich, L Stefan; Vásquez, Julio A; Castilla, Juan Carlos

    2010-09-01

    Unreliable and data-poor marine fishery landings can lead to a lack of regulatory action in fisheries management. Here we use official Chilean landing reports and non-conventional indicators, such as fishers' perceptions and spearfishing competition results, to provide evidence of reef fishes depletions caused by unregulated spearfishing. Results show that the three largest and most emblematic reef fishes targeted mainly by spearfishers (> 98% of landings) [Graus nigra (vieja negra), Semicossyphus darwini (sheephead or pejeperro), and Medialuna ancietae (acha)] show signs of depletion in terms of abundance and size and that overall the catches of reef fishes have shifted from large carnivore species toward smaller-sized omnivore and herbivore species. Information from two snorkeling speargun world championships (1971 and 2004, Iquique, Chile) and from fishers' perceptions shows the mean size of reef fish to be declining. Although the ecological consequences of reef fish depletion are not fully understood in Chile, evidence of spearfishing depleting temperate reef fishes must be explicitly included in policy debates. This would involve bans or strong restrictions on the use of SCUBA and hookah diving gear for spearfishing, and minimum size limits. It may also involve academic and policy discussions regarding conservation and fisheries management synergies within networks of no-take and territorial user-rights fisheries areas, as a strategy for the sustainable management of temperate and tropical reef fisheries.

  7. Depletion patterns and dust evolution in the ISM

    CERN Document Server

    Jones, A P

    1999-01-01

    We review the use of elemental depletions in determining the composition of interstellar dust and present a new interpretation of the elemental depletion patterns for the dust forming elements in a range of diffuse cloud types. We discuss this within the context of dust processing in the ISM and show that Si and Mg are selectively eroded from dust, with respect to Fe, as expected for a sputtering erosion process. However, we find that Si is preferentially and non-stoichiometrically eroded from dust with respect to Mg by some as yet unidentified process that may act in conjunction with grain sputtering. On this basis a new way of interpreting the depletions in terms of `continuous' dust processing through erosion in the interstellar medium is presented. The observed depletion patterns can then be understood in terms of a gradually changing grain chemical composition as the erosion of the atoms proceeds non-stoichiometrically in the low-density interstellar medium. The stoichiometric erosion of multicomponent (...

  8. DURABILITY OF DEPLETED URANIUM AGGREGATES (DUAGG) IN DUCRETE SHIELDING APPLICATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Mattus, Catherine H.; Dole, Leslie R.

    2003-02-27

    The depleted uranium (DU) inventory in the United States exceeds 500,000 metric tonnes. To evaluate the possibilities for reuse of this stockpile of DU, the U.S. Department of Energy (DOE) has created a research and development program to address the disposition of its DU(1). One potential use for this stockpile material is in the fabrication of nuclear shielding casks for the storage, transport, and disposal of spent nuclear fuels. The use of the DU-based shielding would reduce the size and weight of the casks while allowing a level of protection from neutrons and gamma rays comparable to that afforded by steel and concrete. DUAGG (depleted uranium aggregate) is formed of depleted uranium dioxide (DUO2) sintered with a synthetic-basalt-based binder. This study was designed to investigate possible deleterious reactions that could occur between the cement paste and the DUAGG. After 13 months of exposure to a cement pore solution, no deleterious expansive mineral phases were observed to form either with the DUO2 or with the simulated-basalt sintering phases. In the early stages of these exposure tests, Oak Ridge National Laboratory preliminary results confirm that the surface reactions of this aggregate proceed more slowly than expected. This finding may indicate that DUAGG/DUCRETE (depleted uranium concrete) casks could have service lives sufficient to meet the projected needs of DOE and the commercial nuclear power industry.

  9. DEPLETION POTENTIAL OF COLLOIDS:A DIRECT SIMULATION STUDY

    Institute of Scientific and Technical Information of China (English)

    李卫华; 薛松; 马红孺

    2001-01-01

    The depletion interaction between abig sphere and a hard wall and between two big hard spheres in a hard sphere colloidal sytem was studied by the Monte Carlo method.Direct simulation of free energy difference was performed by means of the Acceptance Ratio Method (ARM).

  10. Depletion and the dynamics in colloid-polymer mixtures

    NARCIS (Netherlands)

    Tuinier, Remco; Fan, Tai-Hsi; Taniguchi, Takashi

    The status of work on the influence of nonadsorbing polymers on depletion dynamics in colloidal dispersions is reviewed. In the past focus has been paid to equilibrium properties of colloid-polymer mixtures. In practice the dynamical behaviour is equally important. Dynamic properties including

  11. Depletion potentials in colloidal mixtures of hard spheres and rods.

    Science.gov (United States)

    Li, Weihua; Yang, Tao; Ma, Hong-ru

    2008-01-28

    The depletion potential between a hard sphere and a planar hard wall, or two hard spheres, imposed by suspended rigid spherocylindrical rods is computed by the acceptance ratio method through the application of Monte Carlo simulation. The accurate results and ideal-gas approximation results of the depletion potential are determined with the acceptance ratio method in our simulations. For comparison, the depletion potentials are also studied by using both the density functional theory and Derjaguin approximations. The density profile as a function of positions and orientations of rods, used in the density functional theory, is calculated by Monte Carlo simulation. The potential obtained by the acceptance ratio method is in good agreement with that of density functional theory under the ideal-gas approximation. The comparison between our results and those of other theories suggests that the acceptance ratio method is the only efficient method used to compute the depletion potential induced by nonspherical colloids with the volume fraction beyond the ideal-gas approximation.

  12. Glutamine attenuates post-traumatic glutathione depletion in human muscle.

    Science.gov (United States)

    Fläring, U B; Rooyackers, O E; Wernerman, J; Hammarqvist, F

    2003-03-01

    Glutathione is quantitatively the most important endogenous scavenger system. Glutathione depletion in skeletal muscle is pronounced following major trauma and sepsis in intensive care unit patients. Also, following elective surgery, glutathione depletion occurs in parallel with a progressive decline in muscle glutamine concentration. The present study was designed to test the hypothesis that glutamine supplementation may counteract glutathione depletion in a human trauma model. A homogeneous group of patients (n = 17) undergoing a standardized surgical procedure were prospectively randomly allocated to receive glutamine (0.56 g x day(-1) x kg(-1)) or placebo as part of isonitrogenous and isocaloric nutrition. Percutaneous muscle biopsies and blood samples were taken pre-operatively and at 24 and 72 h after surgery. The concentrations of muscle glutathione and related amino acids were determined in muscle tissue and plasma. In the control (unsupplemented) subjects, total muscle glutathione had decreased by 47+/-8% and 37+/-11% and reduced glutathione had decreased by 53+/-10% and 45+/-16% respectively at 24 and 72 h after surgery (P glutamine supplementation attenuates glutathione depletion in skeletal muscle in humans following standardized surgical trauma.

  13. Electric field diagnostics of the dynamics of equatorial density depletions

    Science.gov (United States)

    Laakso, H.; Maynard, N. C.; Pfaff, R. F.; Aggson, T. L.; Coley, W. R.; Janhunen, P.; Herrero, F. A.

    1997-09-01

    During its life of 10 months, the San Marco D satellite crossed a large number of plasma density depletion channels in the nightside F-region equatorial ionosphere. In-situ measurements of vector electric fields from San Marco D reveal convection velocity variations inside such channels and thus can be used as diagnostics of the dynamics of these plasma depleted regions. Furthermore, in some cases, the temporal evolution of the channel can be inferred from the measurements. In this paper the electric field data are converted to plasma drift velocities in order to illustrate cases where the plasma flow is directed upward or downward in the channel, the channel itself is oriented vertically upward or tilted eastward/westward, or the channel is experiencing a bifurcation or pinching-off process. Although the E × B plasma drift velocities within the depleted channels are commonly a few hundred m s-1, on some occasions electric fields corresponding to speeds as large as 2-3 km s-1 have been observed. The implications for such highly supersonic convection are discussed, including the possible constriction of such high-speed depletion channels at higher altitudes.

  14. Depletion studies of two contrasting D-2 reefs

    Energy Technology Data Exchange (ETDEWEB)

    Gillund, G.N.; Patel, C.

    1980-01-01

    The Nisku B and G pools are 2 W. Pembina D-2 pools with contrasting reservoir properties. Average porosity, permeability, and maximum thickness are 5%, 130 md, and 95 m; and 16.4%, 7100 md and 19 m, respectively. The results of the depletion model studies of waterflooding and miscible flooding and some of the problems that occurred during these studies are reviewed.

  15. Apoptosis and T cell depletion during feline infectious peritonitis

    NARCIS (Netherlands)

    Horzinek, M.C.; Haagmans, B.L.; Egberink, H.F.

    1996-01-01

    Cats that have succumbed to feline infectious peritonitis, an immune- mediated disease caused by variants of feline coronaviruses, show apoptosis and T-cell depletion in their lymphoid organs. The ascitic fluid that develops in the course of the condition causes apoptosis in vitro but only in activa

  16. Electron Microscopy of Living Cells During in Situ Fluorescence Microscopy.

    Science.gov (United States)

    Liv, Nalan; van Oosten Slingeland, Daan S B; Baudoin, Jean-Pierre; Kruit, Pieter; Piston, David W; Hoogenboom, Jacob P

    2016-01-26

    We present an approach toward dynamic nanoimaging: live fluorescence of cells encapsulated in a bionanoreactor is complemented with in situ scanning electron microscopy (SEM) on an integrated microscope. This allows us to take SEM snapshots on-demand, that is, at a specific location in time, at a desired region of interest, guided by the dynamic fluorescence imaging. We show that this approach enables direct visualization, with EM resolution, of the distribution of bioconjugated quantum dots on cellular extensions during uptake and internalization.

  17. Interferometric Synthetic Aperture Microscopy: Computed Imaging for Scanned Coherent Microscopy

    Directory of Open Access Journals (Sweden)

    Stephen A. Boppart

    2008-06-01

    Full Text Available Three-dimensional image formation in microscopy is greatly enhanced by the use of computed imaging techniques. In particular, Interferometric Synthetic Aperture Microscopy (ISAM allows the removal of out-of-focus blur in broadband, coherent microscopy. Earlier methods, such as optical coherence tomography (OCT, utilize interferometric ranging, but do not apply computed imaging methods and therefore must scan the focal depth to acquire extended volumetric images. ISAM removes the need to scan the focus by allowing volumetric image reconstruction from data collected at a single focal depth. ISAM signal processing techniques are similar to the Fourier migration methods of seismology and the Fourier reconstruction methods of Synthetic Aperture Radar (SAR. In this article ISAM is described and the close ties between ISAM and SAR are explored. ISAM and a simple strip-map SAR system are placed in a common mathematical framework and compared to OCT and radar respectively. This article is intended to serve as a review of ISAM, and will be especially useful to readers with a background in SAR.

  18. Ozone depletion, related UVB changes and increased skin cancer incidence

    Science.gov (United States)

    Kane, R. P.

    1998-03-01

    Stratospheric ozone at middle latitudes shows a seasonal variation of about +/-20%, a quasi-biennial oscillation of 1-10% range and a long-term variation in which the level was almost steady up to about 1979 and declined thereafter to the present day by about 10%. These variations are expected to be reflected in solar UVB observed at the ground, but in an opposite direction. Thus UVB should have had a long-term increase of about 10-20%, which should cause an increase in skin cancer incidence of about 20-40%. Skin cancer incidence has increased all over the world, e.g. about 90% in USA during 1974-1990. It is popularly believed that this increase in skin cancer incidence is related to the recent ozone depletion. This seems to be incorrect, for two reasons. Firstly, the observed skin cancer increase is too large (90%) compared with the expected value (40%) from ozone depletion. Secondly, cancer does not develop immediately after exposure to solar UVB. The sunburns may occur within hours; but cancer development and detection may take years, even decades. Hence the observed skin cancer increase since 1974 (no data available for earlier periods) must have occurred due to exposure to solar UVB in the 1950s and 1960s, when there was no ozone depletion. Thus, the skin cancer increase must be attributed to harmful solar UVB levels existing even in the 1960s, accentuated later not by ozone depletion (which started only much later, by 1979) but by other causes, such as a longer human life span, better screening, increasing tendencies of sunbathing at beaches, etc., in affluent societies. On the other hand, the recent ozone depletion and the associated UVB increases will certainly take their toll; only that the effects will not be noticed now but years or decades from now. The concern for the future expressed in the Montreal Protocol for reducing ozone depletion by controlling CFC production is certainly justified, especially because increased UVB is harmful to animal and

  19. MCOR - Monte Carlo depletion code for reference LWR calculations

    Energy Technology Data Exchange (ETDEWEB)

    Puente Espel, Federico, E-mail: fup104@psu.edu [Department of Mechanical and Nuclear Engineering, Pennsylvania State University (United States); Tippayakul, Chanatip, E-mail: cut110@psu.edu [Department of Mechanical and Nuclear Engineering, Pennsylvania State University (United States); Ivanov, Kostadin, E-mail: kni1@psu.edu [Department of Mechanical and Nuclear Engineering, Pennsylvania State University (United States); Misu, Stefan, E-mail: Stefan.Misu@areva.com [AREVA, AREVA NP GmbH, Erlangen (Germany)

    2011-04-15

    Research highlights: > Introduction of a reference Monte Carlo based depletion code with extended capabilities. > Verification and validation results for MCOR. > Utilization of MCOR for benchmarking deterministic lattice physics (spectral) codes. - Abstract: The MCOR (MCnp-kORigen) code system is a Monte Carlo based depletion system for reference fuel assembly and core calculations. The MCOR code is designed as an interfacing code that provides depletion capability to the LANL Monte Carlo code by coupling two codes: MCNP5 with the AREVA NP depletion code, KORIGEN. The physical quality of both codes is unchanged. The MCOR code system has been maintained and continuously enhanced since it was initially developed and validated. The verification of the coupling was made by evaluating the MCOR code against similar sophisticated code systems like MONTEBURNS, OCTOPUS and TRIPOLI-PEPIN. After its validation, the MCOR code has been further improved with important features. The MCOR code presents several valuable capabilities such as: (a) a predictor-corrector depletion algorithm, (b) utilization of KORIGEN as the depletion module, (c) individual depletion calculation of each burnup zone (no burnup zone grouping is required, which is particularly important for the modeling of gadolinium rings), and (d) on-line burnup cross-section generation by the Monte Carlo calculation for 88 isotopes and usage of the KORIGEN libraries for PWR and BWR typical spectra for the remaining isotopes. Besides the just mentioned capabilities, the MCOR code newest enhancements focus on the possibility of executing the MCNP5 calculation in sequential or parallel mode, a user-friendly automatic re-start capability, a modification of the burnup step size evaluation, and a post-processor and test-matrix, just to name the most important. The article describes the capabilities of the MCOR code system; from its design and development to its latest improvements and further ameliorations. Additionally

  20. Depletion potential in hard-sphere mixtures: theory and applications

    Science.gov (United States)

    Roth; Evans; Dietrich

    2000-10-01

    We present a versatile density functional approach (DFT) for calculating the depletion potential in general fluid mixtures. For the standard situation of a single big particle immersed in a sea of small particles near a fixed object, the system is regarded as an inhomogeneous binary mixture of big and small particles in the external field of the fixed object, and the limit of vanishing density of the big species, rho(b)-->0, is taken explicitly. In this limit our approach requires only the equilibrium density profile of a one-component fluid of small particles in the field of the fixed object, and a knowledge of the density independent weight functions which characterize the mixture functional. Thus, for a big particle near a planar wall or a cylinder or another fixed big particle, the relevant density profiles are functions of a single variable, which avoids the numerical complications inherent in brute force DFT. We implement our approach for additive hard-sphere mixtures, comparing our results with computer simulations for the depletion potential of a big sphere of radius R(b) in a sea of small spheres of radius R(s) near (i) a planar hard wall, and (ii) another big sphere. In both cases our results are accurate for size ratios s=R(s)/R(b) as small as 0.1, and for packing fractions of the small spheres eta(s) as large as 0.3; these are the most extreme situations for which reliable simulation data are currently available. Our approach satisfies several consistency requirements, and the resulting depletion potentials incorporate the correct damped oscillatory decay at large separations of the big particles or of the big particle and the wall. By investigating the depletion potential for high size asymmetries we assess the regime of validity of the well-known Derjaguin approximation for hard-sphere mixtures and argue that this fails, even for very small size ratios s, for all but the smallest values of eta(s) where the depletion potential reduces to the Asakura

  1. High-resolution intravital microscopy.

    Directory of Open Access Journals (Sweden)

    Volker Andresen

    Full Text Available Cellular communication constitutes a fundamental mechanism of life, for instance by permitting transfer of information through synapses in the nervous system and by leading to activation of cells during the course of immune responses. Monitoring cell-cell interactions within living adult organisms is crucial in order to draw conclusions on their behavior with respect to the fate of cells, tissues and organs. Until now, there is no technology available that enables dynamic imaging deep within the tissue of living adult organisms at sub-cellular resolution, i.e. detection at the level of few protein molecules. Here we present a novel approach called multi-beam striped-illumination which applies for the first time the principle and advantages of structured-illumination, spatial modulation of the excitation pattern, to laser-scanning-microscopy. We use this approach in two-photon-microscopy--the most adequate optical deep-tissue imaging-technique. As compared to standard two-photon-microscopy, it achieves significant contrast enhancement and up to 3-fold improved axial resolution (optical sectioning while photobleaching, photodamage and acquisition speed are similar. Its imaging depth is comparable to multifocal two-photon-microscopy and only slightly less than in standard single-beam two-photon-microscopy. Precisely, our studies within mouse lymph nodes demonstrated 216% improved axial and 23% improved lateral resolutions at a depth of 80 µm below the surface. Thus, we are for the first time able to visualize the dynamic interactions between B cells and immune complex deposits on follicular dendritic cells within germinal centers (GCs of live mice. These interactions play a decisive role in the process of clonal selection, leading to affinity maturation of the humoral immune response. This novel high-resolution intravital microscopy method has a huge potential for numerous applications in neurosciences, immunology, cancer research and

  2. Fundamental differences between Arctic and Antarctic ozone depletion.

    Science.gov (United States)

    Solomon, Susan; Haskins, Jessica; Ivy, Diane J; Min, Flora

    2014-04-29

    Antarctic ozone depletion is associated with enhanced chlorine from anthropogenic chlorofluorocarbons and heterogeneous chemistry under cold conditions. The deep Antarctic "hole" contrasts with the generally weaker depletions observed in the warmer Arctic. An unusually cold Arctic stratospheric season occurred in 2011, raising the question of how the Arctic ozone chemistry in that year compares with others. We show that the averaged depletions near 20 km across the cold part of each pole are deeper in Antarctica than in the Arctic for all years, although 2011 Arctic values do rival those seen in less-depleted years in Antarctica. We focus not only on averages but also on extremes, to address whether or not Arctic ozone depletion can be as extreme as that observed in the Antarctic. This information provides unique insights into the contrasts between Arctic and Antarctic ozone chemistry. We show that extreme Antarctic ozone minima fall to or below 0.1 parts per million by volume (ppmv) at 18 and 20 km (about 70 and 50 mbar) whereas the lowest Arctic ozone values are about 0.5 ppmv at these altitudes. At a higher altitude of 24 km (30-mbar level), no Arctic data below about 2 ppmv have been observed, including in 2011, in contrast to values more than an order of magnitude lower in Antarctica. The data show that the lowest ozone values are associated with temperatures below -80 °C to -85 °C depending upon altitude, and are closely associated with reduced gaseous nitric acid concentrations due to uptake and/or sedimentation in polar stratospheric cloud particles.

  3. Depleted uranium hexafluoride: The source material for advanced shielding systems

    Energy Technology Data Exchange (ETDEWEB)

    Quapp, W.J.; Lessing, P.A. [Idaho National Engineering Lab., Idaho Falls, ID (United States); Cooley, C.R. [Department of Technology, Germantown, MD (United States)

    1997-02-01

    The U.S. Department of Energy (DOE) has a management challenge and financial liability problem in the form of 50,000 cylinders containing 555,000 metric tons of depleted uranium hexafluoride (UF{sub 6}) that are stored at the gaseous diffusion plants. DOE is evaluating several options for the disposition of this UF{sub 6}, including continued storage, disposal, and recycle into a product. Based on studies conducted to date, the most feasible recycle option for the depleted uranium is shielding in low-level waste, spent nuclear fuel, or vitrified high-level waste containers. Estimates for the cost of disposal, using existing technologies, range between $3.8 and $11.3 billion depending on factors such as the disposal site and the applicability of the Resource Conservation and Recovery Act (RCRA). Advanced technologies can reduce these costs, but UF{sub 6} disposal still represents large future costs. This paper describes an application for depleted uranium in which depleted uranium hexafluoride is converted into an oxide and then into a heavy aggregate. The heavy uranium aggregate is combined with conventional concrete materials to form an ultra high density concrete, DUCRETE, weighing more than 400 lb/ft{sup 3}. DUCRETE can be used as shielding in spent nuclear fuel/high-level waste casks at a cost comparable to the lower of the disposal cost estimates. Consequently, the case can be made that DUCRETE shielded casks are an alternative to disposal. In this case, a beneficial long term solution is attained for much less than the combined cost of independently providing shielded casks and disposing of the depleted uranium. Furthermore, if disposal is avoided, the political problems associated with selection of a disposal location are also avoided. Other studies have also shown cost benefits for low level waste shielded disposal containers.

  4. A novel multiplex bead-based platform highlights the diversity of extracellular vesicles

    Directory of Open Access Journals (Sweden)

    Nina Koliha

    2016-02-01

    Full Text Available The surface protein composition of extracellular vesicles (EVs is related to the originating cell and may play a role in vesicle function. Knowledge of the protein content of individual EVs is still limited because of the technical challenges to analyse small vesicles. Here, we introduce a novel multiplex bead-based platform to investigate up to 39 different surface markers in one sample. The combination of capture antibody beads with fluorescently labelled detection antibodies allows the analysis of EVs that carry surface markers recognized by both antibodies. This new method enables an easy screening of surface markers on populations of EVs. By combining different capture and detection antibodies, additional information on relative expression levels and potential vesicle subpopulations is gained. We also established a protocol to visualize individual EVs by stimulated emission depletion (STED microscopy. Thereby, markers on single EVs can be detected by fluorophore-conjugated antibodies. We used the multiplex platform and STED microscopy to show for the first time that NK cell–derived EVs and platelet-derived EVs are devoid of CD9 or CD81, respectively, and that EVs isolated from activated B cells comprise different EV subpopulations. We speculate that, according to our STED data, tetraspanins might not be homogenously distributed but may mostly appear as clusters on EV subpopulations. Finally, we demonstrate that EV mixtures can be separated by magnetic beads and analysed subsequently with the multiplex platform. Both the multiplex bead-based platform and STED microscopy revealed subpopulations of EVs that have been indistinguishable by most analysis tools used so far. We expect that an in-depth view on EV heterogeneity will contribute to our understanding of different EVs and functions.

  5. High-resolution electron microscopy

    CERN Document Server

    Spence, John C H

    2013-01-01

    This new fourth edition of the standard text on atomic-resolution transmission electron microscopy (TEM) retains previous material on the fundamentals of electron optics and aberration correction, linear imaging theory (including wave aberrations to fifth order) with partial coherence, and multiple-scattering theory. Also preserved are updated earlier sections on practical methods, with detailed step-by-step accounts of the procedures needed to obtain the highest quality images of atoms and molecules using a modern TEM or STEM electron microscope. Applications sections have been updated - these include the semiconductor industry, superconductor research, solid state chemistry and nanoscience, and metallurgy, mineralogy, condensed matter physics, materials science and material on cryo-electron microscopy for structural biology. New or expanded sections have been added on electron holography, aberration correction, field-emission guns, imaging filters, super-resolution methods, Ptychography, Ronchigrams, tomogr...

  6. All-optical photoacoustic microscopy

    Directory of Open Access Journals (Sweden)

    Sung-Liang Chen

    2015-12-01

    Full Text Available Three-dimensional photoacoustic microscopy (PAM has gained considerable attention within the biomedical imaging community during the past decade. Detecting laser-induced photoacoustic waves by optical sensing techniques facilitates the idea of all-optical PAM (AOPAM, which is of particular interest as it provides unique advantages for achieving high spatial resolution using miniaturized embodiments of the imaging system. The review presents the technology aspects of optical-sensing techniques for ultrasound detection, such as those based on optical resonators, as well as system developments of all-optical photoacoustic systems including PAM, photoacoustic endoscopy, and multi-modality microscopy. The progress of different AOPAM systems and their representative applications are summarized.

  7. QUANTITATIVE CONFOCAL LASER SCANNING MICROSCOPY

    Directory of Open Access Journals (Sweden)

    Merete Krog Raarup

    2011-05-01

    Full Text Available This paper discusses recent advances in confocal laser scanning microscopy (CLSM for imaging of 3D structure as well as quantitative characterization of biomolecular interactions and diffusion behaviour by means of one- and two-photon excitation. The use of CLSM for improved stereological length estimation in thick (up to 0.5 mm tissue is proposed. The techniques of FRET (Fluorescence Resonance Energy Transfer, FLIM (Fluorescence Lifetime Imaging Microscopy, FCS (Fluorescence Correlation Spectroscopy and FRAP (Fluorescence Recovery After Photobleaching are introduced and their applicability for quantitative imaging of biomolecular (co-localization and trafficking in live cells described. The advantage of two-photon versus one-photon excitation in relation to these techniques is discussed.

  8. Evaluation of acute tryptophan depletion and sham depletion with a gelatin-based collagen peptide protein mixture

    DEFF Research Database (Denmark)

    Stenbæk, D S; Einarsdottir, H S; Goregliad-Fjaellingsdal, T

    2016-01-01

    Acute Tryptophan Depletion (ATD) is a dietary method used to modulate central 5-HT to study the effects of temporarily reduced 5-HT synthesis. The aim of this study is to evaluate a novel method of ATD using a gelatin-based collagen peptide (CP) mixture. We administered CP-Trp or CP+Trp mixtures...

  9. Hyperspectral holographic Fourier-microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kalenkov, G S [Moscow Institute of Physics and Technology (State University), Moscow (Russian Federation); Kalenkov, S G [Moscow State University of Mechanical Engineering, Moscow (Russian Federation); Shtan' ko, A E [Moscow State University of Technology ' Stankin' , Moscow (Russian Federation)

    2015-04-30

    A detailed theory of the method of holographic recording of hyperspectral wave fields is developed. New experimentally obtained hyperspectral holographic images of microscopic objects are presented. The possibilities of the method are demonstrated experimentally using the examples of urgent microscopy problems: speckle noise suppression, obtaining hyperspectral image of a microscopic object, as well as synthesis of a colour image and obtaining an optical profile of a phase object. (holography)

  10. A history of urine microscopy.

    Science.gov (United States)

    Cameron, J Stewart

    2015-11-01

    The naked-eye appearance of the urine must have been studied by shamans and healers since the Stone Age, and an elaborate interpretation of so-called Uroscopy began around 600 AD as a form of divination. A 1000 years later, the first primitive monocular and compound microscopes appeared in the Netherlands, and along with many other objects and liquids, urine was studied from around 1680 onwards as the enlightenment evolved. However, the crude early instruments did not permit fine study because of chromatic and linear/spherical blurring. Only after complex multi-glass lenses which avoided these problems had been made and used in the 1820s in London by Lister, and in Paris by Chevalier and Amici, could urinary microscopy become a practical, clinically useful tool in the 1830s. Clinical urinary microscopy was pioneered by Rayer and his pupils in Paris (especially Vigla), in the late 1830s, and spread to UK and Germany in the 1840s, with detailed descriptions and interpretations of cells and formed elements of the urinary sediment by Nasse, Henle, Robinson and Golding Bird. Classes were held, most notably by Donné in Paris. After another 50 years, optical microscopy had reached its apogee, with magnifications of over 1000 times obtainable free of aberration, using immersion techniques. Atlases of the urinary sediment were published in all major European countries and in the US. Polarised light and phase contrast was used also after 1900 to study urine, and by the early 20th century, photomicroscopy (pioneered by Donné and Daguerre 50 years previously, but then ignored) became usual for teaching and recording. In the 1940s electron microscopy began, followed by detection of specific proteins and cells using immunofluorescent antibodies. All this had been using handheld methodology. Around 1980, machine-assisted observations began, and have dominated progress since.

  11. Mechanics in Steels through Microscopy

    OpenAIRE

    Tirumalasetty, G. K.

    2013-01-01

    The goal of the study consolidated in this thesis is to understand the mechanics in steels using microscopy. In particular, the mechanical response of Transformation Induced Plasticity (TRIP) steels is correlated with their microstructures. Chapter 1 introduces the current state of the art of TRIP steels, highlighting the importance of microstructure - mechanical properties - applications relationships. In Chapter 2 the material properties and material processing are described into more detai...

  12. ImageJ for microscopy.

    Science.gov (United States)

    Collins, Tony J

    2007-07-01

    ImageJ is an essential tool for us that fulfills most of our routine image processing and analysis requirements. The near-comprehensive range of import filters that allow easy access to image and meta-data, a broad suite processing and analysis routine, and enthusiastic support from a friendly mailing list are invaluable for all microscopy labs and facilities-not just those on a budget.

  13. Comparative study of electron microscopy and scanning probe microscopy in photosynthetic research

    OpenAIRE

    MATĚNOVÁ, Martina

    2009-01-01

    The aim of this study is to compare the ability of transmission electron microscopy, scanning electron microscopy and atomic force microscopy to visualize individual protein complexes. The principle of electron microscopy and atomic force microscopy is explained. For comparision of these methods well characterized photosynthetic complexes LH1, LH2, PSI and PSII were selected.

  14. Janus kinase 3 is expressed in erythrocytes, phosphorylated upon energy depletion and involved in the regulation of suicidal erythrocyte death.

    Science.gov (United States)

    Bhavsar, Shefalee K; Gu, Shuchen; Bobbala, Diwakar; Lang, Florian

    2011-01-01

    Janus kinase 3, a tyrosine kinase expressed in haematopoetic tissues, plays a decisive role in T-lymphocyte survival. JAK3 deficiency leads to (Severe) Combined Immunodeficiency (SCID) resulting from enhanced lymphocyte apoptosis. JAK3 is activated by phosphorylation. Nothing is known about expression of JAK3 in erythrocytes, which may undergo apoptosis-like cell death (eryptosis) characterized by cell membrane scrambling with phosphatidylserine exposure and cell shrinkage. Triggers of eryptosis include energy depletion. The present study utilized immunohistochemistry and confocal microscopy to test for JAK3 expression and phosphorylation, and FACS analysis to determine phosphatidylserine exposure (annexin binding) and cell volume (forward scatter). As a result, JAK3 was expressed in erythrocytes and phosphorylated following 24h and 48h glucose depletion. Forward scatter was slightly but significantly smaller in erythrocytes from JAK3-deficient mice (jak3(-/-)) than in erythrocytes from wild type mice (jak3(+/+)). Annexin V binding was similarly low in both genotypes. The JAK3 inhibitors WHI-P131/JANEX-1 (4-(4'-Hydroxyphenyl)amino-6,7-dimethoxyquinazoline, 156μM) and WHI-P154 (4-[(3'-Bromo-4'-hydroxyphenyl)amino]-6,7-dimethoxyquinazoline, 11.2μM) did not significantly modify annexin V binding or forward scatter. Glucose depletion increased annexin V binding, an effect significantly blunted in jak3(-/-) erythrocytes and in the presence of the JAK3 inhibitors. The observations disclose a completely novel role of Janus kinase 3, i.e. the triggering of cell membrane scrambling in energy depleted erythrocytes.

  15. CRDIAC: Coupled Reactor Depletion Instrument with Automated Control

    Energy Technology Data Exchange (ETDEWEB)

    Steven K. Logan

    2012-08-01

    When modeling the behavior of a nuclear reactor over time, it is important to understand how the isotopes in the reactor will change, or transmute, over that time. This is especially important in the reactor fuel itself. Many nuclear physics modeling codes model how particles interact in the system, but do not model this over time. Thus, another code is used in conjunction with the nuclear physics code to accomplish this. In our code, Monte Carlo N-Particle (MCNP) codes and the Multi Reactor Transmutation Analysis Utility (MRTAU) were chosen as the codes to use. In this way, MCNP would produce the reaction rates in the different isotopes present and MRTAU would use cross sections generated from these reaction rates to determine how the mass of each isotope is lost or gained. Between these two codes, the information must be altered and edited for use. For this, a Python 2.7 script was developed to aid the user in getting the information in the correct forms. This newly developed methodology was called the Coupled Reactor Depletion Instrument with Automated Controls (CRDIAC). As is the case in any newly developed methodology for modeling of physical phenomena, CRDIAC needed to be verified against similar methodology and validated against data taken from an experiment, in our case AFIP-3. AFIP-3 was a reduced enrichment plate type fuel tested in the ATR. We verified our methodology against the MCNP Coupled with ORIGEN2 (MCWO) method and validated our work against the Post Irradiation Examination (PIE) data. When compared to MCWO, the difference in concentration of U-235 throughout Cycle 144A was about 1%. When compared to the PIE data, the average bias for end of life U-235 concentration was about 2%. These results from CRDIAC therefore agree with the MCWO and PIE data, validating and verifying CRDIAC. CRDIAC provides an alternative to using ORIGEN-based methodology, which is useful because CRDIAC's depletion code, MRTAU, uses every available isotope in its

  16. Remediation of soils contaminated with particulate depleted uranium by multi stage chemical extraction

    Energy Technology Data Exchange (ETDEWEB)

    Crean, Daniel E. [Immobilisation Science Laboratory, Department of Materials Science and Engineering, The University of Sheffield (United Kingdom); Centre for Radiochemistry Research, School of Chemistry, The University of Manchester (United Kingdom); Livens, Francis R.; Sajih, Mustafa [Centre for Radiochemistry Research, School of Chemistry, The University of Manchester (United Kingdom); Stennett, Martin C. [Immobilisation Science Laboratory, Department of Materials Science and Engineering, The University of Sheffield (United Kingdom); Grolimund, Daniel; Borca, Camelia N. [Swiss Light Source, Paul Scherrer Institute, Villigen (Switzerland); Hyatt, Neil C., E-mail: n.c.hyatt@sheffield.ac.uk [Immobilisation Science Laboratory, Department of Materials Science and Engineering, The University of Sheffield (United Kingdom)

    2013-12-15

    Highlights: • Batch leaching was examined to remediate soils contaminated with munitions depleted uranium. • Site specific maximum extraction was 42–50% total U in single batch with NH{sub 4}HCO{sub 3}. • Analysis of residues revealed partial leaching and secondary carbonate phases. • Sequential batch leaching alternating between NH{sub 4}HCO{sub 3} and citric acid was designed. • Site specific extraction was increased to 68–87% total U in three batch steps. -- Abstract: Contamination of soils with depleted uranium (DU) from munitions firing occurs in conflict zones and at test firing sites. This study reports the development of a chemical extraction methodology for remediation of soils contaminated with particulate DU. Uranium phases in soils from two sites at a UK firing range, MOD Eskmeals, were characterised by electron microscopy and sequential extraction. Uranium rich particles with characteristic spherical morphologies were observed in soils, consistent with other instances of DU munitions contamination. Batch extraction efficiencies for aqueous ammonium bicarbonate (42–50% total DU extracted), citric acid (30–42% total DU) and sulphuric acid (13–19% total DU) were evaluated. Characterisation of residues from bicarbonate-treated soils by synchrotron microfocus X-ray diffraction and X-ray absorption spectroscopy revealed partially leached U(IV)-oxide particles and some secondary uranyl-carbonate phases. Based on these data, a multi-stage extraction scheme was developed utilising leaching in ammonium bicarbonate followed by citric acid to dissolve secondary carbonate species. Site specific U extraction was improved to 68–87% total U by the application of this methodology, potentially providing a route to efficient DU decontamination using low cost, environmentally compatible reagents.

  17. Whole Body Irradiation Induces Cutaneous Dendritic Cells Depletion via NF-κB Activation

    Directory of Open Access Journals (Sweden)

    Yanyong Yang

    2013-07-01

    Full Text Available Background: Effect of ionizing radiation on cutaneous dendritic cells (cDC is critical to its influence on immune status of the skin, which plays an important role in the progression and recovery of radiation skin sickness. This study was to study the influence of whole body irradiation (WBI on the cDC. Methods: Density of epidermal and dermal DC was determined with a fluorescent microscopy and the DC numbers in lymph node were measured by flow cytometry. A FITC induced migration assay was also used to study the migration of DC. The expressions of cytokines and chemokines were evaluated by Realtime PCR, and the protein level of was measured by Western blot. Results: WBI caused depletion of cDC in epidermal as well as dermal and augmented FITC-induced migration of DC to the draining lymph node (LN. The number of DC migrated from ear explants to the CCL19-containing medium also increased after exposure to WBI. It was also found that WBI increased mRNA level of CCL19/CCL21 as well as CCR7 in LN and skin tissue. The expressions of TNFa, IL-1a, IL-1ß, and IL-6 in skin tissues were also greatly induced by WBI in a dose dependent manner. Finally, we found that WBI induced translocation of nuclear factor κB (NF-κB and that the radiation-induced migration of DC was blocked by NF-κB inhibitor or TLR4 knockout. Conclusion: WBI caused cDC depletion through induction of DC migration to the draining LN, which might result from the activation of NF-κB and the induction of inflammatory microenvironment within the skin.

  18. Tau-mediated nuclear depletion and cytoplasmic accumulation of SFPQ in Alzheimer's and Pick's disease.

    Directory of Open Access Journals (Sweden)

    Yazi D Ke

    Full Text Available Tau dysfunction characterizes neurodegenerative diseases such as Alzheimer's disease (AD and frontotemporal lobar degeneration (FTLD. Here, we performed an unbiased SAGE (serial analysis of gene expression of differentially expressed mRNAs in the amygdala of transgenic pR5 mice that express human tau carrying the P301L mutation previously identified in familial cases of FTLD. SAGE identified 29 deregulated transcripts including Sfpq that encodes a nuclear factor implicated in the splicing and regulation of gene expression. To assess the relevance for human disease we analyzed brains from AD, Pick's disease (PiD, a form of FTLD, and control cases. Strikingly, in AD and PiD, both dementias with a tau pathology, affected brain areas showed a virtually complete nuclear depletion of SFPQ in both neurons and astrocytes, along with cytoplasmic accumulation. Accordingly, neurons harboring either AD tangles or Pick bodies were also depleted of SFPQ. Immunoblot analysis of human entorhinal cortex samples revealed reduced SFPQ levels with advanced Braak stages suggesting that the SFPQ pathology may progress together with the tau pathology in AD. To determine a causal role for tau, we stably expressed both wild-type and P301L human tau in human SH-SY5Y neuroblastoma cells, an established cell culture model of tau pathology. The cells were differentiated by two independent methods, mitomycin C-mediated cell cycle arrest or neuronal differentiation with retinoic acid. Confocal microscopy revealed that SFPQ was confined to nuclei in non-transfected wild-type cells, whereas in wild-type and P301L tau over-expressing cells, irrespective of the differentiation method, it formed aggregates in the cytoplasm, suggesting that pathogenic tau drives SFPQ pathology in post-mitotic cells. Our findings add SFPQ to a growing list of transcription factors with an altered nucleo-cytoplasmic distribution under neurodegenerative conditions.

  19. High pressure elasticity and thermal properties of depleted uranium

    Science.gov (United States)

    Jacobsen, M. K.; Velisavljevic, N.

    2016-04-01

    Studies of the phase diagram of uranium have revealed a wealth of high pressure and temperature phases. Under ambient conditions the crystal structure is well defined up to 100 gigapascals (GPa), but very little information on thermal conduction or elasticity is available over this same range. This work has applied ultrasonic interferometry to determine the elasticity, mechanical, and thermal properties of depleted uranium to 4.5 GPa. Results show general strengthening with applied load, including an overall increase in acoustic thermal conductivity. Further implications are discussed within. This work presents the first high pressure studies of the elasticity and thermal properties of depleted uranium metal and the first real-world application of a previously developed containment system for making such measurements.

  20. Impact of polar ozone depletion on subtropical precipitation.

    Science.gov (United States)

    Kang, S M; Polvani, L M; Fyfe, J C; Sigmond, M

    2011-05-20

    Over the past half-century, the ozone hole has caused a poleward shift of the extratropical westerly jet in the Southern Hemisphere. Here, we argue that these extratropical circulation changes, resulting from ozone depletion, have substantially contributed to subtropical precipitation changes. Specifically, we show that precipitation in the southern subtropics in austral summer increases significantly when climate models are integrated with reduced polar ozone concentrations. Furthermore, the observed patterns of subtropical precipitation change, from 1979 to 2000, are very similar to those in our model integrations, where ozone depletion alone is prescribed. In both climate models and observations, the subtropical moistening is linked to a poleward shift of the extratropical westerly jet. Our results highlight the importance of polar regions for the subtropical hydrological cycle.

  1. The sensitivity of polar ozone depletion to proposed geoengineering schemes.

    Science.gov (United States)

    Tilmes, Simone; Müller, Rolf; Salawitch, Ross

    2008-05-30

    The large burden of sulfate aerosols injected into the stratosphere by the eruption of Mount Pinatubo in 1991 cooled Earth and enhanced the destruction of polar ozone in the subsequent few years. The continuous injection of sulfur into the stratosphere has been suggested as a "geoengineering" scheme to counteract global warming. We use an empirical relationship between ozone depletion and chlorine activation to estimate how this approach might influence polar ozone. An injection of sulfur large enough to compensate for surface warming caused by the doubling of atmospheric CO2 would strongly increase the extent of Arctic ozone depletion during the present century for cold winters and would cause a considerable delay, between 30 and 70 years, in the expected recovery of the Antarctic ozone hole.

  2. Effect of temperature coupling on ozone depletion prediction

    Science.gov (United States)

    Chandra, S.; Butler, D. M.; Stolarski, R. S.

    1978-01-01

    The effects of chlorine perturbations on both the temperature and the ozone distribution in the stratosphere have been studied using a simplified radiative-photochemical model. The model solves the hydrostatic equation for total density in a self-consistent manner as the temperature is changed. Radiative coupling is found to have a significant effect on both the thermal structure and the ozone distribution, particularly in the 35-50-km region. By increasing the ClX mixing ratio by 5.0 ppbv, the temperature in this region is decreased by 5 to 10 K with a slight increase below 30 km. The local ozone depletion around 40 km due to added ClX is smaller compared with the estimate made by keeping the temperature fixed to the ambient condition. However, the integrated effect of radiative coupling is to increase the calculated column ozone depletion by 15% to 25% in this model.

  3. Visualization of stratospheric ozone depletion and the polar vortex

    Science.gov (United States)

    Treinish, Lloyd A.

    1995-01-01

    Direct analysis of spacecraft observations of stratospheric ozone yields information about the morphology of annual austral depletion. Visual correlation of ozone with other atmospheric data illustrates the diurnal dynamics of the polar vortex and contributions from the upper troposphere, including the formation and breakup of the depletion region each spring. These data require care in their presentation to minimize the introduction of visualization artifacts that are erroneously interpreted as data features. Non geographically registered data of differing mesh structures can be visually correlated via cartographic warping of base geometries without interpolation. Because this approach is independent of the realization technique, it provides a framework for experimenting with many visualization strategies. This methodology preserves the fidelity of the original data sets in a coordinate system suitable for three-dimensional, dynamic examination of atmospheric phenomena.

  4. Extracellular Microreactor for the Depletion of Phenylalanine Toward Phenylketonuria Treatment

    DEFF Research Database (Denmark)

    Rigau, Leticia Hosta; Durán, María José York; Kang, Tse Siang;

    2015-01-01

    Phenylketonuria (PKU) is a genetic enzyme defect affecting 1:10 000-20 000 newborn children every year. The amino acid phenylalanine (Phe) is not depleted but accumulates in tissues of several organs, which leads to severe medical conditions. A promising concept to restore the metabolism of the a......Phenylketonuria (PKU) is a genetic enzyme defect affecting 1:10 000-20 000 newborn children every year. The amino acid phenylalanine (Phe) is not depleted but accumulates in tissues of several organs, which leads to severe medical conditions. A promising concept to restore the metabolism...... that the enzyme phenylalanine ammonia lyase can be entrapped within the liposomal compartments with preserved activity, demonstrated by the conversion of Phe into trans-cinnamic acid (t-ca). With the aim to mimic the dynamic environment in the intestine, the Phe conversion is performed in a microfluidic set up...

  5. Nanoscopy for nanoscience: how super-resolution microscopy extends imaging for nanotechnology.

    Science.gov (United States)

    Johnson, Sam A

    2015-01-01

    Imaging methods have presented scientists with powerful means of investigation for centuries. The ability to resolve structures using light microscopes is though limited to around 200 nm. Fluorescence-based super-resolution light microscopy techniques of several principles and methods have emerged in recent years and offer great potential to extend the capabilities of microscopy. This resolution improvement is especially promising for nanoscience where the imaging of nanoscale structures is inherently restricted by the resolution limit of standard forms of light microscopy. Resolution can be improved by several distinct approaches including structured illumination microscopy, stimulated emission depletion, and single-molecule positioning methods such as photoactivated localization microscopy and stochastic optical reconstruction microscopy and several derivative variations of each of these. These methods involve substantial differences in the resolutions achievable in the different axes, speed of acquisition, compatibility with different labels, ease of use, hardware complexity, and compatibility with live biological samples. The field of super-resolution imaging and its application to nanotechnology is relatively new and still rapidly developing. An overview of how these methods may be used with nanomaterials is presented with some examples of pioneering uses of these approaches.

  6. Fully depleted back-illuminated p-channel CCD development

    Energy Technology Data Exchange (ETDEWEB)

    Bebek, Chris J.; Bercovitz, John H.; Groom, Donald E.; Holland, Stephen E.; Kadel, Richard W.; Karcher, Armin; Kolbe, William F.; Oluseyi, Hakeem M.; Palaio, Nicholas P.; Prasad, Val; Turko, Bojan T.; Wang, Guobin

    2003-07-08

    An overview of CCD development efforts at Lawrence Berkeley National Laboratory is presented. Operation of fully-depleted, back-illuminated CCD's fabricated on high resistivity silicon is described, along with results on the use of such CCD's at ground-based observatories. Radiation damage and point-spread function measurements are described, as well as discussion of CCD fabrication technologies.

  7. Radiation survey and decontamination of cape Arza from depleted uranium

    Directory of Open Access Journals (Sweden)

    Vukotić Perko

    2003-01-01

    Full Text Available In the action of NATO A-10 airplanes in 1999, the cape Arza, Serbia and Montenegro was contaminated by depleted uranium. The clean-up operations were undertaken at the site, and 242 uranium projectiles and their 49 larger fragments were removed from the cape. That is about 85% of the total number of projectiles by which Arza was contaminated. Here are described details of the applied procedures and results of the soil radioactivity measurements after decontamination.

  8. Fundamental differences between Arctic and Antarctic ozone depletion

    OpenAIRE

    Solomon, Susan; Haskins, Jessica; Ivy, Diane J.; Min, Flora

    2014-01-01

    Fundamental differences in observed ozone depletion between the Arctic and the Antarctic are shown, clarifying distinctions between both average and extreme ozone decreases in the two hemispheres. Balloon-borne and satellite measurements in the heart of the ozone layer near 18−24 km altitude show that extreme ozone decreases often observed in the Antarctic ozone hole region have not yet been measured in the Arctic in any year, including the unusually cold Arctic spring of 2011. The data provi...

  9. Bromine measurements in ozone depleted air over the Arctic Ocean

    Directory of Open Access Journals (Sweden)

    J. A. Neuman

    2010-07-01

    Full Text Available In situ measurements of ozone, photochemically active bromine compounds, and other trace gases over the Arctic Ocean in April 2008 are used to examine the chemistry and geographical extent of ozone depletion in the arctic marine boundary layer (MBL. Data were obtained from the NOAA WP-3D aircraft during the Aerosol, Radiation, and Cloud Processes affecting Arctic Climate (ARCPAC study and the NASA DC-8 aircraft during the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS study. Fast (1 s and sensitive (detection limits at the low pptv level measurements of BrCl and BrO were obtained from three different chemical ionization mass spectrometer (CIMS instruments, and soluble bromide was measured with a mist chamber. The CIMS instruments also detected Br2. Subsequent laboratory studies showed that HOBr rapidly converts to Br2 on the Teflon instrument inlets. This detected Br2 is identified as active bromine and represents a lower limit of the sum HOBr + Br2. The measured active bromine is shown to likely be HOBr during daytime flights in the arctic. In the MBL over the Arctic Ocean, soluble bromide and active bromine were consistently elevated and ozone was depleted. Ozone depletion and active bromine enhancement were confined to the MBL that was capped by a temperature inversion at 200–500 m altitude. In ozone-depleted air, BrO rarely exceeded 10 pptv and was always substantially lower than soluble bromide that was as high as 40 pptv. BrCl was rarely enhanced above the 2 pptv detection limit, either in the MBL, over Alaska, or in the arctic free troposphere.

  10. A search for relativistic electron induced stratospheric ozone depletion

    Science.gov (United States)

    Aikin, Arthur C.

    1994-01-01

    Possible ozone changes at 1 mb associated with the time variation and precipitation of relativistic electrons are investigated by examining the NIMBUS 7 SBUV ozone data set and corresponding temperatures derived from NMC data. No ozone depletion was observed in high-latitude summer when temperature fluctuations are small. In winter more variation in ozone occurs, but large temperature changes make it difficult to identify specific ozone decreases as being the result of relativistic electron precipitation.

  11. Heterogeneous reactions important in atmospheric ozone depletion: a theoretical perspective.

    Science.gov (United States)

    Bianco, Roberto; Hynes, James T

    2006-02-01

    Theoretical studies of the mechanisms of several heterogeneous reactions involving ClONO(2), H(2)O, HCl, HBr, and H(2)SO(4) important in atmospheric ozone depletion are described, focused primarily on reactions on aqueous aerosol surfaces. Among the insights obtained is the active chemical participation of the surface water molecules in several of these reactions. The general methodology adopted allows reduction of these complex chemical problems to meaningful model systems amenable to quantum chemical calculations.

  12. The International Science and Politics of Depleted Uranium (Briefing charts)

    Science.gov (United States)

    2010-11-01

    Cabrera 3 mrem/y These results for non- carcinogenic risks indicate that there are no adverse impacts expected due to chemical exposure to DU. Iraq...on the health effects of uranium (to include depleted uranium) • The dose makes the poison • Uranium is a weak carcinogen • There are safe levels of...blatant lies”* “ Tobacco industry hired- gun”* * Haleakala Times – December 4th, 2007 What I Actually Do … Science Real The Press • Rediscovers the issue

  13. Effective fiber hypertrophy in satellite cell-depleted skeletal muscle.

    Science.gov (United States)

    McCarthy, John J; Mula, Jyothi; Miyazaki, Mitsunori; Erfani, Rod; Garrison, Kelcye; Farooqui, Amreen B; Srikuea, Ratchakrit; Lawson, Benjamin A; Grimes, Barry; Keller, Charles; Van Zant, Gary; Campbell, Kenneth S; Esser, Karyn A; Dupont-Versteegden, Esther E; Peterson, Charlotte A

    2011-09-01

    An important unresolved question in skeletal muscle plasticity is whether satellite cells are necessary for muscle fiber hypertrophy. To address this issue, a novel mouse strain (Pax7-DTA) was created which enabled the conditional ablation of >90% of satellite cells in mature skeletal muscle following tamoxifen administration. To test the hypothesis that satellite cells are necessary for skeletal muscle hypertrophy, the plantaris muscle of adult Pax7-DTA mice was subjected to mechanical overload by surgical removal of the synergist muscle. Following two weeks of overload, satellite cell-depleted muscle showed the same increases in muscle mass (approximately twofold) and fiber cross-sectional area with hypertrophy as observed in the vehicle-treated group. The typical increase in myonuclei with hypertrophy was absent in satellite cell-depleted fibers, resulting in expansion of the myonuclear domain. Consistent with lack of nuclear addition to enlarged fibers, long-term BrdU labeling showed a significant reduction in the number of BrdU-positive myonuclei in satellite cell-depleted muscle compared with vehicle-treated muscle. Single fiber functional analyses showed no difference in specific force, Ca(2+) sensitivity, rate of cross-bridge cycling and cooperativity between hypertrophied fibers from vehicle and tamoxifen-treated groups. Although a small component of the hypertrophic response, both fiber hyperplasia and regeneration were significantly blunted following satellite cell depletion, indicating a distinct requirement for satellite cells during these processes. These results provide convincing evidence that skeletal muscle fibers are capable of mounting a robust hypertrophic response to mechanical overload that is not dependent on satellite cells.

  14. EZH2 depletion blocks the proliferation of colon cancer cells.

    Directory of Open Access Journals (Sweden)

    Bettina Fussbroich

    Full Text Available The Enhancer of Zeste 2 (EZH2 protein has been reported to stimulate cell growth in some cancers and is therefore considered to represent an interesting new target for therapeutic intervention. Here, we investigated a possible role of EZH2 for the growth control of colon cancer cells. RNA interference (RNAi-mediated intracellular EZH2 depletion led to cell cycle arrest of colon carcinoma cells at the G1/S transition. This was associated with a reduction of cell numbers upon transient transfection of synthetic EZH2-targeting siRNAs and with inhibition of their colony formation capacity upon stable expression of vector-borne siRNAs. We furthermore tested whether EZH2 may repress the growth-inhibitory p27 gene, as reported for pancreatic cancer. However, expression analyses of colon cancer cell lines and colon cancer biopsies did not reveal a consistent correlation between EZH2 and p27 levels. Moreover, EZH2 depletion did not re-induce p27 expression in colon cancer cells, indicating that p27 repression by EZH2 may be cell- or tissue-specific. Whole genome transcriptome analyses identified cellular genes affected by EZH2 depletion in colon cancer cell lines. They included several cancer-associated genes linked to cellular proliferation or invasion, such as Dag1, MageD1, SDC1, Timp2, and Tob1. In conclusion, our results demonstrate that EZH2 depletion blocks the growth of colon cancer cells. These findings might provide benefits for the treatment of colon cancer.

  15. Safety evaluation for packaging (onsite) depleted uranium waste boxes

    Energy Technology Data Exchange (ETDEWEB)

    McCormick, W.A.

    1997-08-27

    This safety evaluation for packaging (SEP) allows the one-time shipment of ten metal boxes and one wooden box containing depleted uranium material from the Fast Flux Test Facility to the burial grounds in the 200 West Area for disposal. This SEP provides the analyses and operational controls necessary to demonstrate that the shipment will be safe for the onsite worker and the public.

  16. Quantitative analysis of cryptic splicing associated with TDP-43 depletion.

    Science.gov (United States)

    Humphrey, Jack; Emmett, Warren; Fratta, Pietro; Isaacs, Adrian M; Plagnol, Vincent

    2017-05-26

    Reliable exon recognition is key to the splicing of pre-mRNAs into mature mRNAs. TDP-43 is an RNA-binding protein whose nuclear loss and cytoplasmic aggregation are a hallmark pathology in amyotrophic lateral sclerosis and frontotemporal dementia (ALS/FTD). TDP-43 depletion causes the aberrant inclusion of cryptic exons into a range of transcripts, but their extent, relevance to disease pathogenesis and whether they are caused by other RNA-binding proteins implicated in ALS/FTD are unknown. We developed an analysis pipeline to discover and quantify cryptic exon inclusion and applied it to publicly available human and murine RNA-sequencing data. We detected widespread cryptic splicing in TDP-43 depletion datasets but almost none in another ALS/FTD-linked protein FUS. Sequence motif and iCLIP analysis of cryptic exons demonstrated that they are bound by TDP-43. Unlike the cryptic exons seen in hnRNP C depletion, those repressed by TDP-43 cannot be linked to transposable elements. Cryptic exons are poorly conserved and inclusion overwhelmingly leads to nonsense-mediated decay of the host transcript, with reduced transcript levels observed in differential expression analysis. RNA-protein interaction data on 73 different RNA-binding proteins showed that, in addition to TDP-43, 7 specifically bind TDP-43 linked cryptic exons. This suggests that TDP-43 competes with other splicing factors for binding to cryptic exons and can repress cryptic exon inclusion. Our quantitative analysis pipeline confirms the presence of cryptic exons during the depletion of TDP-43 but not FUS providing new insight into to RNA-processing dysfunction as a cause or consequence in ALS/FTD.

  17. Geochemical Constraints for Mechanisms of Planetary Differentiation and Volatile Depletion

    OpenAIRE

    Dhaliwal, Jasmeet Kaur

    2016-01-01

    The evolution of the terrestrial planets involved a range of complex processes, including accretion, core formation, post-core formation accretion, mantle differentiation and volatile depletion. The earliest processes of accretion and core formation have largely been overprinted on Earth and Mars, but can be investigated using geochemical measurements of extraterrestrial materials. Highly siderophile elements (HSE; Os, Ir, Ru, Rh, Pt, Pd, Re, Au) preferentially partition into metal phases an...

  18. ABCB10 depletion reduces unfolded protein response in mitochondria.

    Science.gov (United States)

    Yano, Masato

    2017-04-29

    Mitochondria have many functions, including ATP generation. The electron transport chain (ETC) and the coupled ATP synthase generate ATP by consuming oxygen. Reactive oxygen species (ROS) are also produced by ETC, and ROS damage deoxyribonucleic acids, membrane lipids and proteins. Recent analysis indicate that mitochondrial unfolded protein response (UPR(mt)), which enhances expression of mitochondrial chaperones and proteases to remove damaged proteins, is activated when damaged proteins accumulate in the mitochondria. In Caenorhabditis elegans, HAF-1, a putative ortholog of human ABCB10, plays an essential role in signal transduction from mitochondria to nuclei to enhance UPR(mt). Therefore, it is possible that ABCB10 has a role similar to that of HAF-1. However, it has not been reported whether ABCB10 is a factor in the signal transduction pathway to enhance UPR(mt). In this study, ABCB10 was depleted in HepG2 cells using small interfering RNA (siRNA), and the effect was examined. ABCB10 depletion upregulated ROS and the expression of ROS-detoxifying enzymes (SOD2, GSTA1, and GSTA2), and SESN3, a protein induced by ROS to protect the cell from oxidative stress. In addition, ABCB10 depletion significantly decreased expression of UPR(mt)-related mitochondrial chaperones (HSPD1 and DNAJA3), and a mitochondrial protease (LONP1). However, the putative activity of ABCB10 to export peptides from mitochondria was not lost by ABCB10 depletion. Altogether, these data suggest that ABCB10 is involved in UPR(mt) signaling pathway similar to that of HAF-1, although ABCB10 probably does not participate in peptide export from mitochondria. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Effective fiber hypertrophy in satellite cell-depleted skeletal muscle

    Science.gov (United States)

    McCarthy, John J.; Mula, Jyothi; Miyazaki, Mitsunori; Erfani, Rod; Garrison, Kelcye; Farooqui, Amreen B.; Srikuea, Ratchakrit; Lawson, Benjamin A.; Grimes, Barry; Keller, Charles; Van Zant, Gary; Campbell, Kenneth S.; Esser, Karyn A.; Dupont-Versteegden, Esther E.; Peterson, Charlotte A.

    2011-01-01

    An important unresolved question in skeletal muscle plasticity is whether satellite cells are necessary for muscle fiber hypertrophy. To address this issue, a novel mouse strain (Pax7-DTA) was created which enabled the conditional ablation of >90% of satellite cells in mature skeletal muscle following tamoxifen administration. To test the hypothesis that satellite cells are necessary for skeletal muscle hypertrophy, the plantaris muscle of adult Pax7-DTA mice was subjected to mechanical overload by surgical removal of the synergist muscle. Following two weeks of overload, satellite cell-depleted muscle showed the same increases in muscle mass (approximately twofold) and fiber cross-sectional area with hypertrophy as observed in the vehicle-treated group. The typical increase in myonuclei with hypertrophy was absent in satellite cell-depleted fibers, resulting in expansion of the myonuclear domain. Consistent with lack of nuclear addition to enlarged fibers, long-term BrdU labeling showed a significant reduction in the number of BrdU-positive myonuclei in satellite cell-depleted muscle compared with vehicle-treated muscle. Single fiber functional analyses showed no difference in specific force, Ca2+ sensitivity, rate of cross-bridge cycling and cooperativity between hypertrophied fibers from vehicle and tamoxifen-treated groups. Although a small component of the hypertrophic response, both fiber hyperplasia and regeneration were significantly blunted following satellite cell depletion, indicating a distinct requirement for satellite cells during these processes. These results provide convincing evidence that skeletal muscle fibers are capable of mounting a robust hypertrophic response to mechanical overload that is not dependent on satellite cells. PMID:21828094

  20. Apoptosis and T cell depletion during feline infectious peritonitis

    OpenAIRE

    Horzinek, M.C.; Haagmans, B. L.; Egberink, H F

    1996-01-01

    Cats that have succumbed to feline infectious peritonitis, an immune- mediated disease caused by variants of feline coronaviruses, show apoptosis and T-cell depletion in their lymphoid organs. The ascitic fluid that develops in the course of the condition causes apoptosis in vitro but only in activated T cells. Since feline infectious peritonitis virus does not infect T cells, and viral proteins did not inhibit T-cell proliferation, we postulate that soluble mediators released during the infe...

  1. Electron microscopy study of direct laser deposited IN718

    Energy Technology Data Exchange (ETDEWEB)

    Ding, R.G., E-mail: r.ding@bham.ac.uk [School of Metallurgy and Materials, The University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Huang, Z.W.; Li, H.Y. [School of Metallurgy and Materials, The University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Mitchell, I.; Baxter, G. [Rolls-Royce plc., Derby DE24 8BJ (United Kingdom); Bowen, P. [School of Metallurgy and Materials, The University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom)

    2015-08-15

    The microstructure of direct laser deposited (DLD) IN718 has been investigated in detail using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results confirm that the dendrite core microstructure can be linked to the cooling rate experienced during the deposition. A ~ 100 μm wide δ partially dissolved region in the IN718 substrate was observed close to the substrate/deposit boundary. In the deposited IN718, γ/Laves eutectic constituent is the predominant minor microconstituent. Irregular and regular (small) (Nb,Ti)C carbides and a mixture of the carbides and Laves were observed. Most M{sub 3}B{sub 2} borides were nucleated around a (Nb,Ti)C carbide. Needles of δ phase precipitated from the Laves phase were also observed. A complex constituent (of Laves, δ, α-Cr, γ″, and γ matrix) is reported in IN718 for the first time. The formation of α-Cr particles could be related to Cr rejection during the formation and growth of Cr-depleted δ phase. - Highlights: • Secondary phases in IN718 deposits were identified using electron diffraction and EDS. • MC, M{sub 3}B{sub 2}, γ/Laves eutectic and γ/NbC/Laves eutectic were observed. • Needle-like δ phases were precipitated from the Laves phase. • A complex constituent (Laves, δ, α-Cr, γ″ and γ) was reported for the first time.

  2. Inhomogeneous depletion of oxygen ions in metal oxide nanoparticles

    Science.gov (United States)

    Vykhodets, Vladimir B.; Jarvis, Emily A. A.; Kurennykh, Tatiana E.; Beketov, Igor V.; Obukhov, Sviatoslav I.; Samatov, Oleg M.; Medvedev, Anatoly I.; Davletshin, Andrey E.; Whyte, Travis H.

    2016-02-01

    Zirconia and yttria stabilized zirconia (YSZ) have multiple uses, including catalysis, fuel cells, dental applications, and thermal coatings. We employ nuclear reaction analysis to determine elemental composition of YSZ nanoparticles synthesized by laser evaporation including 18O studies to distinguish between oxide and adsorbed oxygen content as a function of surface area. We see dramatic deviation from stoichiometry that can be traced to loss of oxygen from the oxide near the surface of these nanopowders. Density functional calculations are coupled with these experimental studies to explore the electronic structure of nonstoichiometric surfaces achieved through depletion of oxygen. Our results show oxygen-depleted surfaces present under oxygen potentials where stoichiometric, oxygen-terminated surfaces would be favored thermodynamically for crystalline systems. Oxygen depletion at nanopowder surfaces can create effective two-dimensional surface metallic states while maintaining stoichiometry in the underlying nanoparticle core. This insight into nanopowder surfaces applies to dissimilar oxides of aluminum and zirconium indicating synthesis conditions may be more influential than the inherent oxide properties and displaying need for distinct models for nanopowders of these important engineering materials where surface chemistry dominates performance.

  3. Regional strategies for the accelerating global problem of groundwater depletion

    Science.gov (United States)

    Aeschbach-Hertig, Werner; Gleeson, Tom

    2012-12-01

    Groundwater--the world's largest freshwater resource--is critically important for irrigated agriculture and hence for global food security. Yet depletion is widespread in large groundwater systems in both semi-arid and humid regions of the world. Excessive extraction for irrigation where groundwater is slowly renewed is the main cause of the depletion, and climate change has the potential to exacerbate the problem in some regions. Globally aggregated groundwater depletion contributes to sea-level rise, and has accelerated markedly since the mid-twentieth century. But its impacts on water resources are more obvious at the regional scale, for example in agriculturally important parts of India, China and the United States. Food production in such regions can only be made sustainable in the long term if groundwater levels are stabilized. To this end, a transformation is required in how we value, manage and characterize groundwater systems. Technical approaches--such as water diversion, artificial groundwater recharge and efficient irrigation--have failed to balance regional groundwater budgets. They need to be complemented by more comprehensive strategies that are adapted to the specific social, economic, political and environmental settings of each region.

  4. Measurement of camera image sensor depletion thickness with cosmic rays

    CERN Document Server

    Vandenbroucke, J; Bravo, S; Jensen, K; Karn, P; Meehan, M; Peacock, J; Plewa, M; Ruggles, T; Santander, M; Schultz, D; Simons, A L; Tosi, D

    2015-01-01

    Camera image sensors can be used to detect ionizing radiation in addition to optical photons. In particular, cosmic-ray muons are detected as long, straight tracks passing through multiple pixels. The distribution of track lengths can be related to the thickness of the active (depleted) region of the camera image sensor through the known angular distribution of muons at sea level. We use a sample of cosmic-ray muon tracks recorded by the Distributed Electronic Cosmic-ray Observatory to measure the thickness of the depletion region of the camera image sensor in a commercial smart phone, the HTC Wildfire S. The track length distribution prefers a cosmic-ray muon angular distribution over an isotropic distribution. Allowing either distribution, we measure the depletion thickness to be between 13.9~$\\mu$m and 27.7~$\\mu$m. The same method can be applied to additional models of image sensor. Once measured, the thickness can be used to convert track length to incident polar angle on a per-event basis. Combined with ...

  5. PP005. Vitamin D depletion aggravates hypertension in transgenic rats

    DEFF Research Database (Denmark)

    Bjørkholt Andersen, Louise; Herse, Florian; Christesen, Henrik Thybo

    2013-01-01

    overexpressing the human renin and angiotensinogen genes, group 1 (n=18) received vitamin D depleted chow; group 2 (n=15) standard chow and intraperitoneal paricalcitol at 800ng/kg thrice weekly; and group 3 (n=15) standard chow and vehicle injections. Blood pressure (tail cuff) and 24-h albuminuria were...... determined once weekly. After three weeks, animals were sacrificed. Heart tissue was examined for atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) by RT-PCR. RESULTS: The vitamin D depleted group had higher blood pressure at week 1 (mean difference 23.4mmHg, 95% CI 9.1-37.7) and tended...... to have higher blood pressure in weeks 2 and 3 (mean difference 14.3mmHg 95% CI -0.02-28.7 and 15.2mmHg 95% CI -1.5-33). The depletion group had higher heart-to-body weight ratio, and a trend towards higher ANP and BNP levels. The group receiving paricalcitol did not perform better. No differences were...

  6. Alignment of gold nanorods by angular photothermal depletion

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Adam B.; Chow, Timothy T. Y.; Chon, James W. M., E-mail: jchon@swin.edu.au [Centre for Micro-Photonics, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, P.O. Box 218, Hawthorn, 3122 VIC (Australia)

    2014-02-24

    In this paper, we demonstrate that a high degree of alignment can be imposed upon randomly oriented gold nanorod films by angular photothermal depletion with linearly polarized laser irradiation. The photothermal reshaping of gold nanorods is observed to follow quadratic melting model rather than the threshold melting model, which distorts the angular and spectral hole created on 2D distribution map of nanorods to be an open crater shape. We have accounted these observations to the alignment procedures and demonstrated good agreement between experiment and simulations. The use of multiple laser depletion wavelengths allowed alignment criteria over a large range of aspect ratios, achieving 80% of the rods in the target angular range. We extend the technique to demonstrate post-alignment in a multilayer of randomly oriented gold nanorod films, with arbitrary control of alignment shown across the layers. Photothermal angular depletion alignment of gold nanorods is a simple, promising post-alignment method for creating future 3D or multilayer plasmonic nanorod based devices and structures.

  7. Tropical circulation and precipitation response to ozone depletion and recovery

    Science.gov (United States)

    Brönnimann, Stefan; Jacques-Coper, Martín; Rozanov, Eugene; Fischer, Andreas M.; Morgenstern, Olaf; Zeng, Guang; Akiyoshi, Hideharu; Yamashita, Yousuke

    2017-06-01

    Among the few well established changes in atmospheric circulation in recent decades are those caused by stratospheric ozone depletion. They include a strengthening and poleward contraction of the westerly atmospheric circulation over the Southern extratropics, i.e. a strengthening Southern Annular Mode (SAM), in austral spring and summer. Associated effects on extratropical temperature and precipitation and more recently subtropical precipitation have been documented and are understood in a zonal mean framework. We present zonally asymmetric effects of ozone depletion that reach into the tropics and affect atmospheric circulation and precipitation, including the South Pacific Convergence Zone (SPCZ), the most important rainband of the Southern Hemisphere. Using observation-based analyses and model simulations we show that over the 1961-1996 period, ozone depletion led to increased precipitation at the northern flank of the SPCZ and to decreased precipitation to the south. The effects originate from a flow pattern over the southwestern Pacific that extends equatorward and alters the propagation of synoptic waves and thus the position of the SPCZ. Model simulations suggest that anticipated stratospheric ozone recovery over the next decades will reverse these effects.

  8. Frost Induces Respiration and Accelerates Carbon Depletion in Trees.

    Directory of Open Access Journals (Sweden)

    Or Sperling

    Full Text Available Cellular respiration depletes stored carbohydrates during extended periods of limited photosynthesis, e.g. winter dormancy or drought. As respiration rate is largely a function of temperature, the thermal conditions during such periods may affect non-structural carbohydrate (NSC availability and, ultimately, recovery. Here, we surveyed stem responses to temperature changes in 15 woody species. For two species with divergent respirational response to frost, P. integerrima and P. trichocarpa, we also examined corresponding changes in NSC levels. Finally, we simulated respiration-induced NSC depletion using historical temperature data for the western US. We report a novel finding that tree stems significantly increase respiration in response to near freezing temperatures. We observed this excess respiration in 13 of 15 species, deviating 10% to 170% over values predicted by the Arrhenius equation. Excess respiration persisted at temperatures above 0 °C during warming and reoccurred over multiple frost-warming cycles. A large adjustment of NSCs accompanied excess respiration in P. integerrima, whereas P. trichocarpa neither excessively respired nor adjusted NSCs. Over the course of the years included in our model, frost-induced respiration accelerated stem NSC consumption by 8.4 mg (glucose eq. cm(-3 yr(-1 on average in the western US, a level of depletion that may continue to significantly affect spring NSC availability. This novel finding revises the current paradigm of low temperature respiration kinetics.

  9. Rhizosphere effect of different aquatic plants on phosphorus depletion

    Institute of Scientific and Technical Information of China (English)

    Zhenyu WANG; Shengfang WEN; Baoshan XING; Dongmei GAO; Fengmin LI

    2008-01-01

    A series of pot experiments with Alternanthera philoxeroides, Typha latifolia, Sagittaria sagittifolia and Phragmites communis were conducted to assess the phos-phorus depletion effect in the rhizosphere. The ratio of root to shoot, root morphology, phosphorus uptake efficiency and phosphorus utilization efficiency were analyzed. An obvious variation in phosphorus concentrations between the rhizosphere soil and non-rhizosphere soil was observed. The water-soluble P contents in the rhizosphere soil of A. philoxeroides, T. latifolia, S. sagittifolia and P. communis were reduced by 81%, 42%, 18% and 16%, respectively, compared with that in the non-rhizosphere soil. A. philox-eroides had the highest phosphorus uptake efficiency (1.32 mg/m), while T. latifolia achieved the effective phos-phorus depletion by the strong rooting system and the high phosphorus uptake efficiency (0.52 mg/m). T. latifolia not only used phosphorus to produce biomass economically, but also adjusted carbon allocation to the roots to explore the soil for more available phosphorus. A. philoxeroides and T. latifolia were more effective in depleting phosphorus in the rhizosphere than S. sagittifolia and P. communis.

  10. Carbon Monoxide Depletion in Orion B Molecular Cloud Cores

    CERN Document Server

    Savva, D; Phillips, R R; Gibb, A G

    2003-01-01

    We have observed several cloud cores in the Orion B (L1630) molecular cloud in the 2-1 transitions of C18O, C17O and 13C18O. We use these data to show that a model where the cores consist of very optically thick C18O clumps cannot explain their relative intensities. There is strong evidence that the C18O is not very optically thick. The CO emission is compared to previous observations of dust continuum emission to deduce apparent molecular abundances. The abundance values depend somewhat on the temperature but relative to `normal abundance' values, the CO appears to be depleted by about a factor of 10 at the core positions. CO condensation on dust grains provides a natural explanation for the apparent depletion both through gas-phase depletion of CO, and through a possible increase in dust emissivity in the cores. The high brightness of HCO+ relative to CO is then naturally accounted for by time-dependent interstellar chemistry starting from `evolved' initial conditions. Theoretical work has shown that conden...

  11. Frost Induces Respiration and Accelerates Carbon Depletion in Trees.

    Science.gov (United States)

    Sperling, Or; Earles, J Mason; Secchi, Francesca; Godfrey, Jessie; Zwieniecki, Maciej A

    2015-01-01

    Cellular respiration depletes stored carbohydrates during extended periods of limited photosynthesis, e.g. winter dormancy or drought. As respiration rate is largely a function of temperature, the thermal conditions during such periods may affect non-structural carbohydrate (NSC) availability and, ultimately, recovery. Here, we surveyed stem responses to temperature changes in 15 woody species. For two species with divergent respirational response to frost, P. integerrima and P. trichocarpa, we also examined corresponding changes in NSC levels. Finally, we simulated respiration-induced NSC depletion using historical temperature data for the western US. We report a novel finding that tree stems significantly increase respiration in response to near freezing temperatures. We observed this excess respiration in 13 of 15 species, deviating 10% to 170% over values predicted by the Arrhenius equation. Excess respiration persisted at temperatures above 0 °C during warming and reoccurred over multiple frost-warming cycles. A large adjustment of NSCs accompanied excess respiration in P. integerrima, whereas P. trichocarpa neither excessively respired nor adjusted NSCs. Over the course of the years included in our model, frost-induced respiration accelerated stem NSC consumption by 8.4 mg (glucose eq.) cm(-3) yr(-1) on average in the western US, a level of depletion that may continue to significantly affect spring NSC availability. This novel finding revises the current paradigm of low temperature respiration kinetics.

  12. Macrophage depletion disrupts immune balance and energy homeostasis.

    Science.gov (United States)

    Lee, Bonggi; Qiao, Liping; Kinney, Brice; Feng, Gen-Sheng; Shao, Jianhua

    2014-01-01

    Increased macrophage infiltration in tissues including white adipose tissue and skeletal muscle has been recognized as a pro-inflammatory factor that impairs insulin sensitivity in obesity. However, the relationship between tissue macrophages and energy metabolism under non-obese physiological conditions is not clear. To study a homeostatic role of macrophages in energy homeostasis, we depleted tissue macrophages in adult mice through conditional expression of diphtheria toxin (DT) receptor and DT-induced apoptosis. Macrophage depletion robustly reduced body fat mass due to reduced energy intake. These phenotypes were reversed after macrophage recovery. As a potential mechanism, severe hypothalamic and systemic inflammation was induced by neutrophil (NE) infiltration in the absence of macrophages. In addition, macrophage depletion dramatically increased circulating granulocyte colony-stimulating factor (G-CSF) which is indispensable for NE production and tissue infiltration. Our in vitro study further revealed that macrophages directly suppress G-CSF gene expression. Therefore, our study indicates that macrophages may play a critical role in integrating immune balance and energy homeostasis under physiological conditions.

  13. Macrophage depletion disrupts immune balance and energy homeostasis.

    Directory of Open Access Journals (Sweden)

    Bonggi Lee

    Full Text Available Increased macrophage infiltration in tissues including white adipose tissue and skeletal muscle has been recognized as a pro-inflammatory factor that impairs insulin sensitivity in obesity. However, the relationship between tissue macrophages and energy metabolism under non-obese physiological conditions is not clear. To study a homeostatic role of macrophages in energy homeostasis, we depleted tissue macrophages in adult mice through conditional expression of diphtheria toxin (DT receptor and DT-induced apoptosis. Macrophage depletion robustly reduced body fat mass due to reduced energy intake. These phenotypes were reversed after macrophage recovery. As a potential mechanism, severe hypothalamic and systemic inflammation was induced by neutrophil (NE infiltration in the absence of macrophages. In addition, macrophage depletion dramatically increased circulating granulocyte colony-stimulating factor (G-CSF which is indispensable for NE production and tissue infiltration. Our in vitro study further revealed that macrophages directly suppress G-CSF gene expression. Therefore, our study indicates that macrophages may play a critical role in integrating immune balance and energy homeostasis under physiological conditions.

  14. Accounting for Depletion of Oil and Gas Resources in Malaysia

    Energy Technology Data Exchange (ETDEWEB)

    Othman, Jamal, E-mail: jortman@ukm.my; Jafari, Yaghoob, E-mail: yaghoob.jafari@gmail.com [Universiti Kebangsaan Malaysia, Faculty of Economics and Management (Malaysia)

    2012-12-15

    Since oil and gas are non-renewable resources, it is important to identify the extent to which they have been depleted. Such information will contribute to the formulation and evaluation of appropriate sustainable development policies. This paper provides an assessment of the changes in the availability of oil and gas resources in Malaysia by first compiling the physical balance sheet for the period 2000-2007, and then assessing the monetary balance sheets for the said resource by using the Net Present Value method. Our findings show serious reduction in the value of oil reserves from 2001 to 2005, due to changes in crude oil prices, and thereafter the depletion rates decreased. In the context of sustainable development planning, albeit in the weak sustainability sense, it will be important to ascertain if sufficient reinvestments of the estimated resource rents in related or alternative capitals are being attempted by Malaysia. For the study period, the cumulative resource rents were to the tune of RM61 billion. Through a depletion or resource rents policy, the estimated quantum may guide the identification of a reinvestment threshold (after considering needed capital investment for future development of the industry) in light of ensuring the future productive capacity of the economy at the time when the resource is exhausted.

  15. CO depletion --- An evolutionary tracer for molecular clouds

    CERN Document Server

    Liu, Tie; Zhang, Huawei

    2013-01-01

    Planck cold clumps are among the most promising objects to investigate the initial conditions of the evolution of molecular clouds. In this work, by combing the dust emission data from the survey of Planck satellite with the molecular data of $^{12}$CO/$^{13}$CO (1-0) lines from observations with the Purple Mountain Observatory (PMO) 14 m telescope, we investigate the CO abundance, CO depletion and CO-to-H$_{2}$ conversion factor of 674 clumps in the early cold cores (ECC) sample. The median and mean values of the CO abundance are 6.2$\\times10^{-5}$ and 9.1$\\times10^{-5}$, respectively. The mean and median of CO depletion factor are 2.8 and 1.4, respectively. The median value of $X_{CO-to-H_{2}}$ for the whole sample is $3.3\\times10^{20}$ cm$^{-2}$K$^{-1}$km$^{-1}$ s. The CO abundance, CO depletion factor and CO-to-H$_{2}$ conversion factor seems to be strongly correlated to other physical parameters (e.g. dust temperature, dust emissivity spectra index and column density). CO gas severely freeze out in colde...

  16. Combining fluorescence and bioluminescence microscopy.

    Science.gov (United States)

    Goda, Kazuhito; Hatta-Ohashi, Yoko; Akiyoshi, Ryutaro; Sugiyama, Takashi; Sakai, Ikuko; Takahashi, Takeo; Suzuki, Hirobumi

    2015-08-01

    Bioluminescence microscopy has revealed that gene expression in individual cells can respond differently to the same stimulus. To understand this phenomenon, it is important to sequentially observe the series of events from cellular signal transduction to gene expression regulated by specific transcription factors derived from signaling cascades in individual cells. However, these processes have been separately analyzed with fluorescence and bioluminescence microscopy. Furthermore, in culture medium, the background fluorescence of luciferin-a substrate of luciferase in promoter assays of gene expression in cultured cells-confounds the simultaneous observation of fluorescence and bioluminescence. Therefore, we optimized conditions for optical filter sets based on spectral properties and the luciferin concentration based on cell permeability for fluorescence observation combined with bioluminescence microscopy. An excitation and emission filter set (492-506 nm and 524-578 nm) was suitable for green fluorescent protein and yellow fluorescent protein imaging of cells, and >100 μM luciferin was acceptable in culture medium based on kinetic constants and the estimated intracellular concentration. Using these parameters, we present an example of sequential fluorescence and bioluminescence microscopic observation of signal transduction (translocation of protein kinase C alpha from the cytoplasm to the plasma membrane) coupled with activation of gene expression by nuclear factor of kappa light polypeptide B in individual cells and show that the gene expression response is not completely concordant with upstream signaling following stimulation with phorbol-12-myristate-13-acetate. Our technique is a powerful imaging tool for analysis of heterogeneous gene expression together with upstream signaling in live single cells.

  17. Aperture scanning Fourier ptychographic microscopy

    Science.gov (United States)

    Ou, Xiaoze; Chung, Jaebum; Horstmeyer, Roarke; Yang, Changhuei

    2016-01-01

    Fourier ptychographic microscopy (FPM) is implemented through aperture scanning by an LCOS spatial light modulator at the back focal plane of the objective lens. This FPM configuration enables the capturing of the complex scattered field for a 3D sample both in the transmissive mode and the reflective mode. We further show that by combining with the compressive sensing theory, the reconstructed 2D complex scattered field can be used to recover the 3D sample scattering density. This implementation expands the scope of application for FPM and can be beneficial for areas such as tissue imaging and wafer inspection. PMID:27570705

  18. Twin-Photon Confocal Microscopy

    CERN Document Server

    Simon, D S

    2010-01-01

    A recently introduced two-channel confocal microscope with correlated detection promises up to 50% improvement in transverse spatial resolution [Simon, Sergienko, Optics Express {\\bf 18}, 9765 (2010)]. Here we move further by introducing a triple-confocal correlated microscope, exploiting the correlations present in optical parametric amplifiers. It is based on tight focusing of pump radiation onto a thin sample positioned in front of a nonlinear crystal, followed by coincidence detection of signal and idler photons, each focused onto a pinhole. This approach offers further resolution enhancement in microscopy.

  19. Visual-servoing optical microscopy

    Science.gov (United States)

    Callahan, Daniel E.; Parvin, Bahram

    2009-06-09

    The present invention provides methods and devices for the knowledge-based discovery and optimization of differences between cell types. In particular, the present invention provides visual servoing optical microscopy, as well as analysis methods. The present invention provides means for the close monitoring of hundreds of individual, living cells over time: quantification of dynamic physiological responses in multiple channels; real-time digital image segmentation and analysis; intelligent, repetitive computer-applied cell stress and cell stimulation; and the ability to return to the same field of cells for long-term studies and observation. The present invention further provides means to optimize culture conditions for specific subpopulations of cells.

  20. Synthetic incoherence for electron microscopy.

    Science.gov (United States)

    Levine, Zachary H; Dunstan, Robyn M

    2007-08-01

    Tomographic studies of submicrometer samples in materials science using electron microscopy have been inhibited by diffraction effects. In the present work, we describe a practical method for ameliorating these effects. First, we find an analytic expression for the mutual coherence function for hollow-cone illumination. Then, we use this analytic expression to propose a Gaussian weighting of hollow-cone illumination, which we name tapered solid-cone illumination, and present an analytic expression for its mutual coherence function. Finally, we investigate numerically an n-ring approximation to tapered solid-cone illumination. The results suggest a method for removing diffraction effects and hence enabling tomography.

  1. Polyethyleneimine as tracer for electron microscopy

    NARCIS (Netherlands)

    Schurer, Jacob Willem

    1980-01-01

    In this thesis the development of a tracer particle for use in electron microscopy is described. Attempts were made to use this tracer particle in immuno-electron microscopy and to trace negatively charged tissue components. ... Zie: Summary

  2. NICHD Microscopy and Imaging Core (MIC)

    Data.gov (United States)

    Federal Laboratory Consortium — The NICHD Microscopy and Imaging Core (MIC) is designed as a multi-user research facility providing training and instrumentation for high resolution microscopy and...

  3. Image scanning microscopy with radially polarized light

    Science.gov (United States)

    Xiao, Yun; Zhang, Yunhai; Wei, Tongda; Huang, Wei; Shi, Yaqin

    2017-03-01

    In order to improve the resolution of image scanning microscopy, we present a method based on image scanning microscopy and radially polarized light. According to the theory of image scanning microscopy, we get the effective point spread function of image scanning microscopy with the longitudinal component of radially polarized light and a 1 AU detection area, and obtain imaging results of the analyzed samples using this method. Results show that the resolution can be enhanced by 7% compared with that in image scanning microscopy with circularly polarized light, and is 1.54-fold higher than that in confocal microscopy with a pinhole of 1 AU. Additionally, the peak intensity of ISM is 1.54-fold higher than that of a confocal microscopy with a pinhole of 1 AU. In conclusion, the combination of the image scanning microscopy and the radially polarized light could improve the resolution, and it could realize high-resolution and high SNR imaging at the same time.

  4. Depletion calculations for the McClellan Nuclear Radiation Center.

    Energy Technology Data Exchange (ETDEWEB)

    Klann, R. T.; Newell, D. L.

    1997-12-08

    Depletion calculations have been performed for the McClellan reactor history from January 1990 through August 1996. A database has been generated for continuing use by operations personnel which contains the isotopic inventory for all fuel elements and fuel-followed control rods maintained at McClellan. The calculations are based on the three-dimensional diffusion theory code REBUS-3 which is available through the Radiation Safety Information Computational Center (RSICC). Burnup-dependent cross-sections were developed at zero power temperatures and full power temperatures using the WIMS code (also available through RSICC). WIMS is based on discretized transport theory to calculate the neutron flux as a function of energy and position in a one-dimensional cell. Based on the initial depletion calculations, a method was developed to allow operations personnel to perform depletion calculations and update the database with a minimal amount of effort. Depletion estimates and calculations can be performed by simply entering the core loading configuration, the position of the control rods at the start and end of cycle, the reactor power level, the duration of the reactor cycle, and the time since the last reactor cycle. The depletion and buildup of isotopes of interest (heavy metal isotopes, erbium isotopes, and fission product poisons) are calculated for all fuel elements and fuel-followed control rods in the MNRC inventory. The reactivity loss from burnup and buildup of fission product poisons and the peak xenon buildup after shutdown are also calculated. The reactivity loss from going from cold zero power to hot full power can also be calculated by using the temperature-dependent, burnup-dependent cross-sections. By calculating all of these reactivity effects, operations personnel are able to estimate the total excess reactivity necessary to run the reactor for the given cycle. This method has also been used to estimate the worth of individual control rods. Using this

  5. DEPLETION POTENTIAL OF COLLOIDS:A DIRECT SIMULATION STUDY

    Institute of Scientific and Technical Information of China (English)

    LI; Wei-hua(

    2001-01-01

    [1]Asakura S, Oosawa F. Surface tension of high-poly-mer solution [J]. J Chem Phys, 1954, 22: 1255~ 1255.[2]Ye X, Narayanan T, Tong P, et al. Depletion interactions in colloid-polymer mixtures [J]. Phys Rev E, 1996, 54: 6500~6510.[3]Kaplan P D, Faucheux L P, Libchaber A J. Direct observation of the entropic potential in a binary suspension [J]. Phys Rev Lett, 1994, 73: 2793~2796.[4]Ohshima Y N, Sakagami H, Okumoto K, et al. Direct measurement of infinite simal depletion force in a colloid-polymer mixture by laser radiation pressure [J]. Phys Rev Lett, 1997, 78: 3963~3966.[5]Dinsmore A D, Yodh A G, Pine D J. Entropic control particle motion using passive surface microstructures [J]. Nature (London), 1996, 383: 239~242.[6]Dinsmore A D, Wong D T, Nelson P, et al. Hard spheres in vecicles: curvature-induced forces and particle-induced curvature [J]. Phys Rev Lett, 1998, 80: 409~412.[7]Gtzelmann B, Evans R, Dietrich S. Depletion forces in fluids [J]. Phys Rev E, 1998, 57: 6785~6800.[8]Miao Y, Cates M E, Lekkerkerker H N W. Depletion force in colloidal systems [J]. Physica A, 1995, 222: 10~24.[9]Biben J, Bladon P, Frenkel D. Depletion effects in binary hard-sphere fluids [J]. J Phys: Condens Matter, 1996, 8: 10799~10821.[10]Dickman R, Attard P, Simonian V. Entropic forces in binary hard sphere mixture: Theory and simulation [J]. J Chem Phys, 1997, 107: 205~213.[11]Bennett C H. Efficient estimation of free energy differences from Monte Carlo data [J]. J Comput Phys, 1976, 22: 245~268; see also Allen M P, Tildesley D J. Computer Simulation of Liquids (Chap.7) [M]. Oxford: Clarendon Press. 1994.

  6. Nanocharacterization: Atomic Scale Visualization with Microscopy

    Science.gov (United States)

    Broadbridge, Christine

    2007-10-01

    This workshop will include an overview presentation of nanotechnology and nanocharacterization tools (electron microscopy and atomic force microscopy) as well as examples of curricular components for middle and high school teachers. Tours/demonstrations of microscopy facilities in the IMS facility at UConn will be provided.

  7. Plasmonics Enhanced Smartphone Fluorescence Microscopy

    KAUST Repository

    Wei, Qingshan

    2017-05-12

    Smartphone fluorescence microscopy has various applications in point-of-care (POC) testing and diagnostics, ranging from e.g., quantification of immunoassays, detection of microorganisms, to sensing of viruses. An important need in smartphone-based microscopy and sensing techniques is to improve the detection sensitivity to enable quantification of extremely low concentrations of target molecules. Here, we demonstrate a general strategy to enhance the detection sensitivity of a smartphone-based fluorescence microscope by using surface-enhanced fluorescence (SEF) created by a thin metal-film. In this plasmonic design, the samples are placed on a silver-coated glass slide with a thin spacer, and excited by a laser-diode from the backside through a glass hemisphere, generating surface plasmon polaritons. We optimized this mobile SEF system by tuning the metal-film thickness, spacer distance, excitation angle and polarization, and achieved ~10-fold enhancement in fluorescence intensity compared to a bare glass substrate, which enabled us to image single fluorescent particles as small as 50 nm in diameter and single quantum-dots. Furthermore, we quantified the detection limit of this platform by using DNA origami-based brightness standards, demonstrating that ~80 fluorophores per diffraction-limited spot can be readily detected by our mobile microscope, which opens up new opportunities for POC diagnostics and sensing applications in resource-limited-settings.

  8. Ozone depletion and climate change: impacts on UV radiation.

    Science.gov (United States)

    McKenzie, R L; Aucamp, P J; Bais, A F; Björn, L O; Ilyas, M; Madronich, S

    2011-02-01

    The Montreal Protocol is working, but it will take several decades for ozone to return to 1980 levels. The atmospheric concentrations of ozone depleting substances are decreasing, and ozone column amounts are no longer decreasing. Mid-latitude ozone is expected to return to 1980 levels before mid-century, slightly earlier than predicted previously. However, the recovery rate will be slower at high latitudes. Springtime ozone depletion is expected to continue to occur at polar latitudes, especially in Antarctica, in the next few decades. Because of the success of the Protocol, increases in UV-B radiation have been small outside regions affected by the Antarctic ozone hole, and have been difficult to detect. There is a large variability in UV-B radiation due to factors other than ozone, such as clouds and aerosols. There are few long-term measurements available to confirm the increases that would have occurred as a result of ozone depletion. At mid-latitudes UV-B irradiances are currently only slightly greater than in 1980 (increases less than ~5%), but increases have been substantial at high and polar latitudes where ozone depletion has been larger. Without the Montreal Protocol, peak values of sunburning UV radiation could have been tripled by 2065 at mid-northern latitudes. This would have had serious consequences for the environment and for human health. There are strong interactions between ozone depletion and changes in climate induced by increasing greenhouse gases (GHGs). Ozone depletion affects climate, and climate change affects ozone. The successful implementation of the Montreal Protocol has had a marked effect on climate change. The calculated reduction in radiative forcing due to the phase-out of chlorofluorocarbons (CFCs) far exceeds that from the measures taken under the Kyoto protocol for the reduction of GHGs. Thus the phase-out of CFCs is currently tending to counteract the increases in surface temperature due to increased GHGs. The amount of

  9. 3D multiplexed immunoplasmonics microscopy

    Science.gov (United States)

    Bergeron, Éric; Patskovsky, Sergiy; Rioux, David; Meunier, Michel

    2016-07-01

    Selective labelling, identification and spatial distribution of cell surface biomarkers can provide important clinical information, such as distinction between healthy and diseased cells, evolution of a disease and selection of the optimal patient-specific treatment. Immunofluorescence is the gold standard for efficient detection of biomarkers expressed by cells. However, antibodies (Abs) conjugated to fluorescent dyes remain limited by their photobleaching, high sensitivity to the environment, low light intensity, and wide absorption and emission spectra. Immunoplasmonics is a novel microscopy method based on the visualization of Abs-functionalized plasmonic nanoparticles (fNPs) targeting cell surface biomarkers. Tunable fNPs should provide higher multiplexing capacity than immunofluorescence since NPs are photostable over time, strongly scatter light at their plasmon peak wavelengths and can be easily functionalized. In this article, we experimentally demonstrate accurate multiplexed detection based on the immunoplasmonics approach. First, we achieve the selective labelling of three targeted cell surface biomarkers (cluster of differentiation 44 (CD44), epidermal growth factor receptor (EGFR) and voltage-gated K+ channel subunit KV1.1) on human cancer CD44+ EGFR+ KV1.1+ MDA-MB-231 cells and reference CD44- EGFR- KV1.1+ 661W cells. The labelling efficiency with three stable specific immunoplasmonics labels (functionalized silver nanospheres (CD44-AgNSs), gold (Au) NSs (EGFR-AuNSs) and Au nanorods (KV1.1-AuNRs)) detected by reflected light microscopy (RLM) is similar to the one with immunofluorescence. Second, we introduce an improved method for 3D localization and spectral identification of fNPs based on fast z-scanning by RLM with three spectral filters corresponding to the plasmon peak wavelengths of the immunoplasmonics labels in the cellular environment (500 nm for 80 nm AgNSs, 580 nm for 100 nm AuNSs and 700 nm for 40 nm × 92 nm AuNRs). Third, the developed

  10. Kelvin probe force microscopy in liquid using electrochemical force microscopy

    Directory of Open Access Journals (Sweden)

    Liam Collins

    2015-01-01

    Full Text Available Conventional closed loop-Kelvin probe force microscopy (KPFM has emerged as a powerful technique for probing electric and transport phenomena at the solid–gas interface. The extension of KPFM capabilities to probe electrostatic and electrochemical phenomena at the solid–liquid interface is of interest for a broad range of applications from energy storage to biological systems. However, the operation of KPFM implicitly relies on the presence of a linear lossless dielectric in the probe–sample gap, a condition which is violated for ionically-active liquids (e.g., when diffuse charge dynamics are present. Here, electrostatic and electrochemical measurements are demonstrated in ionically-active (polar isopropanol, milli-Q water and aqueous NaCl and ionically-inactive (non-polar decane liquids by electrochemical force microscopy (EcFM, a multidimensional (i.e., bias- and time-resolved spectroscopy method. In the absence of mobile charges (ambient and non-polar liquids, KPFM and EcFM are both feasible, yielding comparable contact potential difference (CPD values. In ionically-active liquids, KPFM is not possible and EcFM can be used to measure the dynamic CPD and a rich spectrum of information pertaining to charge screening, ion diffusion, and electrochemical processes (e.g., Faradaic reactions. EcFM measurements conducted in isopropanol and milli-Q water over Au and highly ordered pyrolytic graphite electrodes demonstrate both sample- and solvent-dependent features. Finally, the feasibility of using EcFM as a local force-based mapping technique of material-dependent electrostatic and electrochemical response is investigated. The resultant high dimensional dataset is visualized using a purely statistical approach that does not require a priori physical models, allowing for qualitative mapping of electrostatic and electrochemical material properties at the solid–liquid interface.

  11. Diamond particles as nanoantennas for nitrogen-vacancy color centers

    CERN Document Server

    Greffet, J -J; Besbes, M; Lai, N D; Treussart, F; Roch, J -F

    2011-01-01

    The photoluminescence of nitrogen-vacancy (NV) centers in diamond nanoparticles exhibits specific properties as compared to NV centers in bulk diamond. For instance large fluctuations of lifetime and brightness from particle to particle have been reported. It has also been observed that for nanocrystals much smaller than the mean luminescence wavelength, the particle size sets a lower threshold for resolution in Stimulated Emission Depletion (STED) microscopy. We show that all these features can be quantitatively understood by realizing that the absorption-emission of light by the NV center is mediated by the diamond nanoparticle which behaves as a dielectric nanoantenna.

  12. In utero depletion of fetal hematopoietic stem cells improves engraftment after neonatal transplantation in mice

    OpenAIRE

    Derderian, S. Christopher; Togarrati, P. Priya; King, Charmin; Moradi, Patriss W.; Reynaud, Damien; Czechowicz, Agnieszka; Weissman, Irving L; MacKenzie, Tippi C.

    2014-01-01

    In utero injection of an antibody against the c-Kit receptor can effectively deplete host HSCs in mice.In utero depletion of host HSCs leads to significantly increased engraftment after neonatal congenic hematopoietic cell transplantation.

  13. Nature gives us strength: exposure to nature counteracts ego-depletion.

    Science.gov (United States)

    Chow, Jason T; Lau, Shun

    2015-01-01

    Previous research rarely investigated the role of physical environment in counteracting ego-depletion. In the present research, we hypothesized that exposure to natural environment counteracts ego-depletion. Three experiments were conducted to test this hypothesis. In Experiment 1, initially depleted participants who viewed pictures of nature scenes showed greater persistence on a subsequent anagram task than those who were given a rest period. Experiment 2 expanded upon this finding by showing that natural environment enhanced logical reasoning performance after ego-depleting task. Experiment 3 adopted a two- (depletion vs. no-depletion) -by-two (nature exposure vs. urban exposure) factorial design. We found that nature exposure moderated the effect of depletion on anagram task performance. Taken together, the present studies offer a viable and novel strategy to mitigate the negative impacts of ego-depletion.

  14. Mars Accreted a Volatile Element-Depleted Late Veneer Indicating Early Delivery of Martian Volatiles

    Science.gov (United States)

    Becker, H.; Wang, Z.

    2016-08-01

    Chalcophile elements in SNC meteorites are used to constrain abundances in the Martian mantle. Strong depletion of Te relative to highly siderophile elements suggests a volatile element-depleted late veneer, requiring that volatiles arrived earlier.

  15. Grand Canonical Ensemble Monte Carlo Simulation of Depletion Interactions in Colloidal Suspensions

    Institute of Scientific and Technical Information of China (English)

    GUO Ji-Yuan; XIAO Chang-Ming

    2008-01-01

    Depletion interactions in colloidal suspensions confined between two parallel plates are investigated by using acceptance ratio method with grand canonical ensemble Monte Carlo simulation.The numerical results show that both the depletion potential and depletion force are affected by the confinement from the two parallel plates.Furthermore,it is found that in the grand canonical ensemble Monte Carlo simulation,the depletion interactions are strongly affected by the generalized chemical potential.

  16. Multiphoton microscopy in life sciences.

    Science.gov (United States)

    König, K

    2000-11-01

    Near infrared (NIR) multiphoton microscopy is becoming a novel optical tool of choice for fluorescence imaging with high spatial and temporal resolution, diagnostics, photochemistry and nanoprocessing within living cells and tissues. Three-dimensional fluorescence imaging based on non-resonant two-photon or three-photon fluorophor excitation requires light intensities in the range of MW cm(-2) to GW cm(-2), which can be derived by diffraction limited focusing of continuous wave and pulsed NIR laser radiation. NIR lasers can be employed as the excitation source for multifluorophor multiphoton excitation and hence multicolour imaging. In combination with fluorescence in situ hybridization (FISH), this novel approach can be used for multi-gene detection (multiphoton multicolour FISH). Owing to the high NIR penetration depth, non-invasive optical biopsies can be obtained from patients and ex vivo tissue by morphological and functional fluorescence imaging of endogenous fluorophores such as NAD(P)H, flavin, lipofuscin, porphyrins, collagen and elastin. Recent botanical applications of multiphoton microscopy include depth-resolved imaging of pigments (chlorophyll) and green fluorescent proteins as well as non-invasive fluorophore loading into single living plant cells. Non-destructive fluorescence imaging with multiphoton microscopes is limited to an optical window. Above certain intensities, multiphoton laser microscopy leads to impaired cellular reproduction, formation of giant cells, oxidative stress and apoptosis-like cell death. Major intracellular targets of photodamage in animal cells are mitochondria as well as the Golgi apparatus. The damage is most likely based on a two-photon excitation process rather than a one-photon or three-photon event. Picosecond and femtosecond laser microscopes therefore provide approximately the same safe relative optical window for two-photon vital cell studies. In labelled cells, additional phototoxic effects may occur via

  17. 26 CFR 52.4681-1 - Taxes imposed with respect to ozone-depleting chemicals.

    Science.gov (United States)

    2010-04-01

    ...)) for the calendar year in which the sale or use occurs; and (iii) The ozone-depletion factor... 26 Internal Revenue 17 2010-04-01 2010-04-01 false Taxes imposed with respect to ozone-depleting... to ozone-depleting chemicals. (a) Taxes imposed. Sections 4681 and 4682 impose the following taxes...

  18. Phase Aberrations in Diffraction Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Marchesini, S; Chapman, H N; Barty, A; Howells, M R; Spence, J H; Cui, C; Weierstall, U; Minor, A M

    2005-09-29

    In coherent X-ray diffraction microscopy the diffraction pattern generated by a sample illuminated with coherent x-rays is recorded, and a computer algorithm recovers the unmeasured phases to synthesize an image. By avoiding the use of a lens the resolution is limited, in principle, only by the largest scattering angles recorded. However, the imaging task is shifted from the experiment to the computer, and the algorithm's ability to recover meaningful images in the presence of noise and limited prior knowledge may produce aberrations in the reconstructed image. We analyze the low order aberrations produced by our phase retrieval algorithms. We present two methods to improve the accuracy and stability of reconstructions.

  19. Note: Direct piezoelectric effect microscopy.

    Science.gov (United States)

    Mori, T J A; Stamenov, P; Dorneles, L S

    2015-07-01

    An alternative method for investigating piezoelectric surfaces is suggested, exploiting the direct piezoeffect. The technique relies on acoustic (ultrasonic) excitation of the imaged surface and mapping of the resulting oscillatory electric potential. The main advantages arise from the spatial resolution of the conductive scanning probe microscopy in combination with the relatively large magnitude of the forward piezo signal Upf, which can be of the order of tens of mV even for non-ferroelectric piezoelectric materials. The potency of this experimental strategy is illustrated with measurements on well-crystallized quartz surfaces, where Upf ∼ 50 mV, for a piezoelectric coefficient of d33 = - 2.27  ×  10(-12) m/V, and applied stress of about T3 ∼ 5.7 kPa.

  20. Optical Photon Reassignment Microscopy (OPRA)

    CERN Document Server

    Roth, Stephan; Wicker, Kai; Heintzmann, Rainer

    2013-01-01

    To enhance the resolution of a confocal laser scanning microscope the additional information of a pinhole plane image taken at every excitation scan position can be used [C. J. R. Sheppard, Super-resolution in confocal imaging, Optik 80, 5354 (1988)]. This photon reassignment principle is based on the fact that the most probable position of an emitter is at half way between the nominal focus of the excitation laser and the position corresponding to the (off centre) detection position. Therefore, by reassigning the detected photons to this place, an image with enhanced detection efficiency and resolution is obtained. Here we present optical photon reassignment microscopy (OPRA) which realises this concept in an all-optical way obviating the need for image-processing. With the help of an additional intermediate optical beam expansion between descanning and a further rescanning of the detected light, an image with the advantages of photon reassignment can be acquired. Due to its simplicity and flexibility this m...

  1. Photoacoustic microscopy in tissue engineering

    Directory of Open Access Journals (Sweden)

    Xin Cai

    2013-03-01

    Full Text Available Photoacoustic tomography (PAT is an attractive modality for noninvasive, volumetric imaging of scattering media such as biological tissues. By choosing the ultrasonic detection frequency, PAT enables scalable spatial resolution with an imaging depth of up to ∼7 cm while maintaining a high depth-to-resolution ratio of ∼200 and consistent optical absorption contrasts. Photoacoustic microscopy (PAM, the microscopic embodiment of PAT, aims to image at millimeter depth and micrometer-scale resolution. PAM is well-suited for characterizing three-dimensional scaffold-based samples, including scaffolds themselves, cells, and blood vessels, both qualitatively and quantitatively. Here we review our previous work on applications of PAM in tissue engineering and then discuss its future developments.

  2. Magnetic microscopy of layered structures

    CERN Document Server

    Kuch, Wolfgang; Fischer, Peter; Hillebrecht, Franz Ulrich

    2015-01-01

    This book presents the important analytical technique of magnetic microscopy. This method is applied to analyze layered structures with high resolution. This book presents a number of layer-resolving magnetic imaging techniques that have evolved recently. Many exciting new developments in magnetism rely on the ability to independently control the magnetization in two or more magnetic layers in micro- or nanostructures. This in turn requires techniques with the appropriate spatial resolution and magnetic sensitivity. The book begins with an introductory overview, explains then the principles of the various techniques and gives guidance to their use. Selected examples demonstrate the specific strengths of each method. Thus the book is a valuable resource for all scientists and practitioners investigating and applying magnetic layered structures.

  3. Electronic detectors for electron microscopy.

    Science.gov (United States)

    Faruqi, A R; McMullan, G

    2011-08-01

    Electron microscopy (EM) is an important tool for high-resolution structure determination in applications ranging from condensed matter to biology. Electronic detectors are now used in most applications in EM as they offer convenience and immediate feedback that is not possible with film or image plates. The earliest forms of electronic detector used routinely in transmission electron microscopy (TEM) were charge coupled devices (CCDs) and for many applications these remain perfectly adequate. There are however applications, such as the study of radiation-sensitive biological samples, where film is still used and improved detectors would be of great value. The emphasis in this review is therefore on detectors for use in such applications. Two of the most promising candidates for improved detection are: monolithic active pixel sensors (MAPS) and hybrid pixel detectors (of which Medipix2 was chosen for this study). From the studies described in this review, a back-thinned MAPS detector appears well suited to replace film in for the study of radiation-sensitive samples at 300 keV, while Medipix2 is suited to use at lower energies and especially in situations with very low count rates. The performance of a detector depends on the energy of electrons to be recorded, which in turn is dependent on the application it is being used for; results are described for a wide range of electron energies ranging from 40 to 300 keV. The basic properties of detectors are discussed in terms of their modulation transfer function (MTF) and detective quantum efficiency (DQE) as a function of spatial frequency.

  4. Compressed sensing traction force microscopy.

    Science.gov (United States)

    Brask, Jonatan Bohr; Singla-Buxarrais, Guillem; Uroz, Marina; Vincent, Romaric; Trepat, Xavier

    2015-10-01

    Adherent cells exert traction forces on their substrate, and these forces play important roles in biological functions such as mechanosensing, cell differentiation and cancer invasion. The method of choice to assess these active forces is traction force microscopy (TFM). Despite recent advances, TFM remains highly sensitive to measurement noise and exhibits limited spatial resolution. To improve the resolution and noise robustness of TFM, here we adapt techniques from compressed sensing (CS) to the reconstruction of the traction field from the substrate displacement field. CS enables the recovery of sparse signals at higher resolution from lower resolution data. Focal adhesions (FAs) of adherent cells are spatially sparse implying that traction fields are also sparse. Here we show, by simulation and by experiment, that the CS approach enables circumventing the Nyquist-Shannon sampling theorem to faithfully reconstruct the traction field at a higher resolution than that of the displacement field. This allows reaching state-of-the-art resolution using only a medium magnification objective. We also find that CS improves reconstruction quality in the presence of noise. A great scientific advance of the past decade is the recognition that physical forces determine an increasing list of biological processes. Traction force microscopy which measures the forces that cells exert on their surroundings has seen significant recent improvements, however the technique remains sensitive to measurement noise and severely limited in spatial resolution. We exploit the fact that the force fields are sparse to boost the spatial resolution and noise robustness by applying ideas from compressed sensing. The novel method allows high resolution on a larger field of view. This may in turn allow better understanding of the cell forces at the multicellular level, which are known to be important in wound healing and cancer invasion. Copyright © 2015 Acta Materialia Inc. Published by Elsevier

  5. Resolution enhancement techniques in microscopy

    Science.gov (United States)

    Cremer, Christoph; Masters, Barry R.

    2013-05-01

    We survey the history of resolution enhancement techniques in microscopy and their impact on current research in biomedicine. Often these techniques are labeled superresolution, or enhanced resolution microscopy, or light-optical nanoscopy. First, we introduce the development of diffraction theory in its relation to enhanced resolution; then we explore the foundations of resolution as expounded by the astronomers and the physicists and describe the conditions for which they apply. Then we elucidate Ernst Abbe's theory of optical formation in the microscope, and its experimental verification and dissemination to the world wide microscope communities. Second, we describe and compare the early techniques that can enhance the resolution of the microscope. Third, we present the historical development of various techniques that substantially enhance the optical resolution of the light microscope. These enhanced resolution techniques in their modern form constitute an active area of research with seminal applications in biology and medicine. Our historical survey of the field of resolution enhancement uncovers many examples of reinvention, rediscovery, and independent invention and development of similar proposals, concepts, techniques, and instruments. Attribution of credit is therefore confounded by the fact that for understandable reasons authors stress the achievements from their own research groups and sometimes obfuscate their contributions and the prior art of others. In some cases, attribution of credit is also made more complex by the fact that long term developments are difficult to allocate to a specific individual because of the many mutual connections often existing between sometimes fiercely competing, sometimes strongly collaborating groups. Since applications in biology and medicine have been a major driving force in the development of resolution enhancing approaches, we focus on the contribution of enhanced resolution to these fields.

  6. Depleted-Heterojunction Colloidal Quantum Dot Solar Cells

    KAUST Repository

    Pattantyus-Abraham, Andras G.

    2010-06-22

    Colloidal quantum dot (CQD) photovoltaics combine low-cost solution processability with quantum size-effect tunability to match absorption with the solar spectrum. Rapid recent advances in CQD photovoltaics have led to impressive 3.6% AM1.5 solar power conversion efficiencies. Two distinct device architectures and operating mechanisms have been advanced. The first-the Schottky device-was optimized and explained in terms of a depletion region driving electron-hole pair separation on the semiconductor side of a junction between an opaque low-work-function metal and a p-type CQD film. The second-the excitonic device-employed a CQD layer atop a transparent conductive oxide (TCO) and was explained in terms of diffusive exciton transport via energy transfer followed by exciton separation at the type-II heterointerface between the CQD film and the TCO. Here we fabricate CQD photovoltaic devices on TCOs and show that our devices rely on the establishment of a depletion region for field-driven charge transport and separation, and that they also exploit the large bandgap of the TCO to improve rectification and block undesired hole extraction. The resultant depletedheterojunction solar cells provide a 5.1% AM1.5 power conversion efficiency. The devices employ infrared-bandgap size-effect-tuned PbS CQDs, enabling broadband harvesting of the solar spectrum. We report the highest opencircuit voltages observed in solid-state CQD solar cells to date, as well as fill factors approaching 60%, through the combination of efficient hole blocking (heterojunction) and very small minority carrier density (depletion) in the large-bandgap moiety. © 2010 American Chemical Society.

  7. Selection of a management strategy for depleted uranium hexafluoride

    Energy Technology Data Exchange (ETDEWEB)

    Patton, S.E.; Hanrahan, E.J.; Bradley, C.E.

    1995-09-06

    A consequence of the uranium enrichment process used in the United States (US) is the accumulation of a significant amount of depleted uranium hexafluoride (UF{sub 6}). Currently, approximately 560,000 metric tons of the material are stored at three different sites. The US Department of Energy (DOE) has recently initiated a program to consider alternative strategies for the cost-effective and environmentally safe long-term management of this inventory of depleted UF{sub 6}. The program involves a technology and engineering assessment of proposed management options (use/reuse, conversion, storage, or disposal) and an analysis of the potential environmental impacts and life-cycle costs of alternative management strategies. The information obtained from the studies will be used by the DOE to select a preferred long-term management strategy. The selection and implementation of a management strategy will involve consideration of a number of important issues such as environmental, health, and safety effects; the balancing of risks versus costs in a context of reduced government spending; socioeconomic implications, including effects on the domestic and international uranium industry; the technical status of proposed uses or technologies; and public involvement in the decision making process. Because of its provisions for considering a wide range of relevant issues and involving the public, this program has become a model for future DOE materials disposition programs. This paper presents an overview of the Depleted Uranium Hexafluoride Management Program. Technical findings of the program to date are presented, and major issues involved in selecting and implementing a management strategy are discussed.

  8. Depletion mapping and constrained optimization to support managing groundwater extraction

    Science.gov (United States)

    Fienen, Michael N.; Bradbury, Kenneth R.; Kniffin, Maribeth; Barlow, Paul M.

    2017-01-01

    Groundwater models often serve as management tools to evaluate competing water uses including ecosystems, irrigated agriculture, industry, municipal supply, and others. Depletion potential mapping—showing the model-calculated potential impacts that wells have on stream baseflow - can form the basis for multiple potential management approaches in an oversubscribed basin. Specific management approaches can include scenarios proposed by stakeholders, systematic changes in well pumping based on depletion potential, and formal constrained optimization, which can be used to quantify the tradeoff between water use and stream baseflow. Variables such as the maximum amount of reduction allowed in each well and various groupings of wells using, for example, K-means clustering considering spatial proximity and depletion potential are considered. These approaches provide a potential starting point and guidance for resource managers and stakeholders to make decisions about groundwater management in a basin, spreading responsibility in different ways. We illustrate these approaches in the Little Plover River basin in central Wisconsin, United States—home to a rich agricultural tradition, with farmland and urban areas both in close proximity to a groundwater-dependent trout stream. Groundwater withdrawals have reduced baseflow supplying the Little Plover River below a legally established minimum. The techniques in this work were developed in response to engaged stakeholders with various interests and goals for the basin. They sought to develop a collaborative management plan at a watershed scale that restores the flow rate in the river in a manner that incorporates principles of shared governance and results in effective and minimally disruptive changes in groundwater extraction practices.

  9. Stratospheric ozone depletion from future nitrous oxide increases

    Directory of Open Access Journals (Sweden)

    W. Wang

    2014-12-01

    Full Text Available We have investigated the impact of the assumed nitrous oxide (N2O increases on stratospheric chemistry and dynamics using a series of idealized simulations with a coupled chemistry-climate model (CCM. In a future cooler stratosphere the net yield of NOy from N2O is shown to decrease in a reference run following the IPCC A1B scenario, but NOy can still be significantly increased by extra increases of N2O over 2001–2050. Over the last decade of simulations, 50% increases in N2O result in a maximal 6% reduction in ozone mixing ratios in the middle stratosphere at around 10 hPa and an average 2% decrease in the total ozone column (TCO compared with the control run. This enhanced destruction could cause an ozone decline in the first half of this century in the middle stratosphere around 10 hPa, while global TCO still shows an increase at the same time. The results from a multiple linear regression analysis and sensitivity simulations with different forcings show that the chemical effect of N2O increases dominates the N2O-induced ozone depletion in the stratosphere, while the dynamical and radiative effects of N2O increases are overall insignificant. The analysis of the results reveals that the ozone depleting potential of N2O varies with the time period and is influenced by the environmental conditions. For example, carbon dioxide (CO2 increases can strongly offset the ozone depletion effect of N2O.

  10. Assessment of volume depletion in children with malaria.

    Directory of Open Access Journals (Sweden)

    Timothy Planche

    2004-10-01

    Full Text Available BACKGROUND: The degree of volume depletion in severe malaria is currently unknown, although knowledge of fluid compartment volumes can guide therapy. To assist management of severely ill children, and to test the hypothesis that volume changes in fluid compartments reflect disease severity, we measured body compartment volumes in Gabonese children with malaria. METHODS AND FINDINGS: Total body water volume (TBW and extracellular water volume (ECW were estimated in children with severe or moderate malaria and in convalescence by tracer dilution with heavy water and bromide, respectively. Intracellular water volume (ICW was derived from these parameters. Bioelectrical impedance analysis estimates of TBW and ECW were calibrated against dilution methods, and bioelectrical impedance analysis measurements were taken daily until discharge. Sixteen children had severe and 19 moderate malaria. Severe childhood malaria was associated with depletion of TBW (mean [SD] of 37 [33] ml/kg, or 6.7% [6.0%] relative to measurement at discharge. This is defined as mild dehydration in other conditions. ECW measurements were normal on admission in children with severe malaria and did not rise in the first few days of admission. Volumes in different compartments (TBW, ECW, and ICW were not related to hyperlactataemia or other clinical and laboratory markers of disease severity. Moderate malaria was not associated with a depletion of TBW. CONCLUSIONS: Significant hypovolaemia does not exacerbate complications of severe or moderate malaria. As rapid rehydration of children with malaria may have risks, we suggest that fluid replacement regimens should aim to correct fluid losses over 12-24 h.

  11. PKCι depletion initiates mitotic slippage-induced senescence in glioblastoma.

    Science.gov (United States)

    Restall, Ian J; Parolin, Doris A E; Daneshmand, Manijeh; Hanson, Jennifer E L; Simard, Manon A; Fitzpatrick, Megan E; Kumar, Ritesh; Lavictoire, Sylvie J; Lorimer, Ian A J

    2015-01-01

    Cellular senescence is a tumor suppressor mechanism where cells enter a permanent growth arrest following cellular stress. Oncogene-induced senescence (OIS) is induced in non-malignant cells following the expression of an oncogene or inactivation of a tumor suppressor. Previously, we have shown that protein kinase C iota (PKCι) depletion induces cellular senescence in glioblastoma cells in the absence of a detectable DNA damage response. Here we demonstrate that senescent glioblastoma cells exhibit an aberrant centrosome morphology. This was observed in basal levels of senescence, in p21-induced senescence, and in PKCι depletion-induced senescence. In addition, senescent glioblastoma cells are polyploid, Ki-67 negative and arrest at the G1/S checkpoint, as determined by expression of cell cycle regulatory proteins. These markers are all consistent with cells that have undergone mitotic slippage. Failure of the spindle assembly checkpoint to function properly can lead to mitotic slippage, resulting in the premature exit of mitotic cells into the G1 phase of the cell cycle. Although in G1, these cells have the replicated DNA and centrosomal phenotype of a cell that has entered mitosis and failed to divide. Overall, we demonstrate that PKCι depletion initiates mitotic slippage-induced senescence in glioblastoma cells. To our knowledge, this is the first evidence of markers of mitotic slippage directly in senescent cells by co-staining for senescence-associated β-galactosidase and immunofluorescence markers in the same cell population. We suggest that markers of mitotic slippage be assessed in future studies of senescence to determine the extent of mitotic slippage in the induction of cellular senescence.

  12. L-Tryptophan depletion bioreactor, a possible cancer therapy

    Directory of Open Access Journals (Sweden)

    Rolf Bambauer

    2015-04-01

    Full Text Available The cancer therapeutic strategies knownto date are not adequate for all cancer patients. Most of them are followed by a high rate of side effects and complications. The L-tryptophan depletion bioreactor is described as a possible new method of cancer therapy. L-tryptophan is an essential amino acid which has been recognized as an important cancer nutrient and its removal can lead to destruction of the tumour. Normal human cells or tumor cells cannot synthesize L-tryptophan and therefore tumor resistance is unlikely to develop. L-tryptophan is also a constituent for different bio-molecules such as Serotonin, Melatonin, and is needed for other synthesis processes in the cell growth. L-tryptophan degrading enzymes with 3 iso-enzymes called tryptophan side chain oxydase (TSO I, II, III were isolated. The 3 iso-enzymes can be differentiated by tryptic digestion. They have different molecular weights with different effectivenesses. All the TSO enzymes have heme that can catalyze essentially similar reactions involving L-tryptophan as a substrate. The most effective TSO is the type TSO III. A column which contained TSO as a bioreactor was integrated in a plasmapheresis unit and tested it in different animals. In sheep and rabbits L-tryptophan depletion in plasma was shown at 95% and 100% rates respectively by a single pass through the bioreactor. The results in immune supprimized rats with tumors were impressive, too. In 20 different tumor cell lines there were different efficacies. Brest cancer and medulloblastoma showed the greatest efficacy of L-tryptophan degrading. The gene technology of TSO production from Pseudomonas is associated with formation of endotoxins. This disadvantage can be prevented by different washing procedures or by using fungal sources for the TSO production. TSO III is developed to treat cancer diseases successfully, and has low side effects. A combination of L-tryptophan depletion with all available cancer therapies is

  13. Acetic acid induces pH-independent cellular energy depletion in Salmonella enterica.

    Science.gov (United States)

    Tan, Sin Mei; Lee, Sui Mae; Dykes, Gary A

    2015-03-01

    Weak organic acids are widely used as preservatives and disinfectants in the food industry. Despite their widespread use, the antimicrobial mode of action of organic acids is still not fully understood. This study investigated the effect of acetic acid on the cell membranes and cellular energy generation of four Salmonella strains. Using a nucleic acid/protein assay, it was established that acetic acid did not cause leakage of intracellular components from the strains. A scanning electron microscopy study further confirmed that membrane disruption was not the antimicrobial mode of action of acetic acid. Some elongated Salmonella cells observed in the micrographs indicated a possibility that acetic acid may inhibit DNA synthesis in the bacterial cells. Using an ATP assay, it was found that at a neutral pH, acetic acid caused cellular energy depletion with an ADP/ATP ratio in the range between 0.48 and 2.63 (pacid molecules. The antimicrobial effect of acetic acid was better under acidic conditions (ADP/ATP ratio of 5.56 ± 1.27; pacid molecules can act together. We concluded that the inhibitory effect of acetic acid is not solely attributable to acidic pH but also to undissociated acid molecules. This finding has implication for the use of acetic acid as an antimicrobial against Salmonella on food products, such as chicken meat, which can buffer its pH.

  14. Products of in Situ Corrosion of Depleted Uranium Ammunition in Bosnia and Herzegovina Soils.

    Science.gov (United States)

    Wang, Yuheng; von Gunten, Konstantin; Bartova, Barbora; Meisser, Nicolas; Astner, Markus; Burger, Mario; Bernier-Latmani, Rizlan

    2016-11-15

    Hundreds of tons of depleted uranium (DU) ammunition were used in previous armed conflicts in Iraq, Bosnia and Herzegovina, and Serbia/Kosovo. The majority (>90%) of DU penetrators miss their target and, if left in the environment, corrode in these postconflict zones. Thus, the best way to understand the fate of bulk DU material in the environment is to characterize the corrosion products of intact DU penetrators under field conditions for extended periods of time. However, such studies are scarce. To fill this knowledge gap, we characterized corrosion products formed from two intact DU penetrators that remained in soils in Bosnia and Herzegovina for over seven years. We used a combination of X-ray powder diffraction, electron microscopy, and X-ray absorption spectroscopy. The results show that metaschoepite (UO3(H2O)2) was a main component of the two DU corrosion products. Moreover, studtite ((UO2)O2(H2O)2·2(H2O)) and becquerelite (Ca(UO2)6O4(OH)6·8(H2O)) were also identified in the corrosion products. Their formation through transformation of metaschoepite was a result of the geochemical conditions under which the penetrators corroded. Moreover, we propose that the transformation of metaschoepite to becquerelite or studtite in the DU corrosion products would decrease the potential for mobilization of U from corroded DU penetrators exposed to similar environments in postconflict areas.

  15. Remediation of soils contaminated with particulate depleted uranium by multi stage chemical extraction.

    Science.gov (United States)

    Crean, Daniel E; Livens, Francis R; Sajih, Mustafa; Stennett, Martin C; Grolimund, Daniel; Borca, Camelia N; Hyatt, Neil C

    2013-12-15

    Contamination of soils with depleted uranium (DU) from munitions firing occurs in conflict zones and at test firing sites. This study reports the development of a chemical extraction methodology for remediation of soils contaminated with particulate DU. Uranium phases in soils from two sites at a UK firing range, MOD Eskmeals, were characterised by electron microscopy and sequential extraction. Uranium rich particles with characteristic spherical morphologies were observed in soils, consistent with other instances of DU munitions contamination. Batch extraction efficiencies for aqueous ammonium bicarbonate (42-50% total DU extracted), citric acid (30-42% total DU) and sulphuric acid (13-19% total DU) were evaluated. Characterisation of residues from bicarbonate-treated soils by synchrotron microfocus X-ray diffraction and X-ray absorption spectroscopy revealed partially leached U(IV)-oxide particles and some secondary uranyl-carbonate phases. Based on these data, a multi-stage extraction scheme was developed utilising leaching in ammonium bicarbonate followed by citric acid to dissolve secondary carbonate species. Site specific U extraction was improved to 68-87% total U by the application of this methodology, potentially providing a route to efficient DU decontamination using low cost, environmentally compatible reagents.

  16. Cost Analysis of Remediation Systems for Depleted Uranium

    Science.gov (United States)

    2014-04-01

    Ownership Cost ERDC/EL TR-14-5 xii US United States WBS Work Breakdown Structure WHA Tungsten Heavy Alloys WHO World Health Organization yd...fact, the DU long rod kinetic energy penetrators outperform their modern conventional Tungsten Heavy Alloys ( WHA ) counterparts by about 8-10...Depleted uranium has a density of 18.9 g/cm3 versus 17.6 g/cm3 of WHA . Also, DU has a high rate of deformation, which allows it to “self-sharpen

  17. Characterizing the transcriptome upon depletion of RNA processing factors

    DEFF Research Database (Denmark)

    Herudek, Jan

    nucleus and is responsible for the proper processing and decay of a wide range of RNA molecules. Notably, the RNA exosome complex associates with a plethora of co-factors and activators that assist in the recognition of specific RNA substrates. Although many exosome partners have been characterized...... this method with CRISPR/Cas9 genome editing to pursue rapid depletion of endogenous protein. Applying this technology, I aim to study dynamics of the RNA decay machinery and obtain a deeper understanding of recently characterized ncRNAs....

  18. Plasma depletion layer: the role of the slow mode waves

    Directory of Open Access Journals (Sweden)

    Y. L. Wang

    2004-12-01

    Full Text Available The plasma depletion layer (PDL is a layer on the sunward side of the magnetopause with lower plasma density and higher magnetic field compared to their corresponding values in the upstream magnetosheath. The depletion layer usually occurs during northward (IMF conditions with low magnetic shear across the magnetopause. We have previously validated the Raeder global model by comparing the computed formation of a magnetosheath density depletion with in-situ observations. We also have performed a detailed force analysis and found the varying roles that different MHD forces play along the path of a plasma parcel flowing around the magnetopause. That study resulted in a new description of the behavior of magnetosheath magnetic flux tubes which better explains the plasma depletion along a flux tube. The slow mode waves have been observed in the magnetosheath and have been used to explain the formation of the PDL in some of the important PDL models. In this study, we extend our former work by investigating the possible role of the slow mode waves for the formation of the PDL, using global MHD model simulations. We propose a new technique to test where a possible slow mode front may occur in the magnetosheath by comparing the slow mode group velocity with the local flow velocity. We find that the slow mode fronts can exist in certain regions in the magnetosheath under certain solar wind conditions. The existence and location of such fronts clearly depend on the IMF. We do not see from our global simulation results either the sharpening of the slow mode front into a slow mode shock or noticeable changes of the flow and field in the magnetosheath across the slow mode front, which implies that the slow mode front is not likely responsible for the formation of the PDL, at least for the stable solar wind conditions used in these simulations. Also, we do not see the two-layered slow mode structures shown in some observations and proposed in certain PDL

  19. Indirect Measurement of Evapotranspiration from Soil Moisture Depletion

    Science.gov (United States)

    Li, M.; Chen, Y.

    2007-12-01

    Direct and in situ measurement of evapotranspiration (ET), such as the eddy covariance (EC) method, is often expensive and complicated, especially over tall canopy. In view of soil water balance, depletion of soil moisture can be attributed to canopy ET when horizontal soil moisture movement is negligible and percolation ceases. This study computed the daily soil moisture depletion at the Lien-Hua-Chih (LHC) station (23°55'52"N, 120°53'39"E, 773 m elevation) from July, 2004 to June, 2007 to estimate daily ET. The station is inside an experimental watershed of a natural evergreen forest and the canopy height is about 17 m. Rainfall days are assumed to be no ET. For those days with high soil moisture content, normally 2 to 3 days after significant rainfall input, ET is estimated by potential ET. Soil moistures were measured by capacitance probes at -10 cm, - 30 cm, -50 cm, -70 cm, and -90 cm. A soil heat flux plate was placed at -5 cm. In the summer of 2006, a 22 m tall observation tower was constructed. Temperature and relative humidity sensors were placed every 5 m from ground surface to 20 m for inner and above canopy measurements. Net radiation and wind speed/directions were also installed. A drainage gauge was installed at -50 cm to collect infiltrated water. Continuous measurements of low response instruments were recorded every 30-minute averaged from 10-minute samplings. A nearby weather station provides daily pan evaporation and precipitation data. Since the response of soil water variations is relatively slow to the fluctuations of atmospheric forcing, only daily ET is estimated from daily soil moisture depletion. The annual average precipitation is 2902 mm and the annual average ET is 700 mm. The seasonal ET patterns of the first two water years are similar. The third year has a higher ET because soil moisture was recharged frequently by rainfall In order to examine the applicability of this approach, an EC system, including a 3-D sonic anemometer (Young

  20. Depletion of mtDNA: syndromes and genes.

    Science.gov (United States)

    Alberio, Simona; Mineri, Rossana; Tiranti, Valeria; Zeviani, Massimo

    2007-01-01

    Maintenance of mitochondrial DNA (mtDNA) requires the concerted activity of several nuclear-encoded factors that participate in its replication, being part of the mitochondrial replisome or ensuring the balanced supply of dNTPs to mitochondria. In the past decade, a growing number of syndromes associated with dysfunction due to tissue-specific depletion of mtDNA (MDS) have been reported. This article reviews the current knowledge of the genes responsible for these disorders, the impact of different mutations in the epidemiology of MDS and their role in the pathogenic mechanisms underlying the different clinical presentations.