Science.gov

Sample records for enables fluorescent dimming

  1. Research and Development of a New Field Enhanced Low Temperature Thermionic Cathode that Enables Fluorescent Dimming and Loan Shedding without Auxiliary Cathode Heating

    SciTech Connect

    Feng Jin

    2009-01-07

    This is the final report for project entitled 'Research and development of a new field enhanced low temperature thermionic cathode that enables fluorescent dimming and load shedding without auxiliary cathode heating', under Agreement Number: DE-FC26-04NT-42329. Under this project, a highly efficient CNT based thermionic cathode was demonstrated. This cathode is capable of emitting electron at a current density two order of magnitude stronger then a typical fluorescent cathode at same temperatures, or capable of emitting at same current density but at temperature about 300 C lower than that of a fluorescent cathode. Detailed fabrication techniques were developed including CVD growth of CNTs and sputter deposition of oxide thin films on CNTs. These are mature technologies that have been widely used in industry for large scale materials processing and device fabrications, thus, with further development work, the techniques developed in this project can be scaled-up in manufacturing environment. The prototype cathodes developed in this project were tested in lighting plasma discharge environment. In many cases, they not only lit and sustain the plasma, but also out perform the fluorescent cathodes in key parameters such like cathode fall voltages. More work will be needed to further evaluate more detailed and longer term performance of the prototype cathode in lighting plasma.

  2. Spectral and structural comparison between bright and dim green fluorescent proteins in Amphioxus.

    PubMed

    Bomati, Erin K; Haley, Joy E; Noel, Joseph P; Deheyn, Dimitri D

    2014-06-27

    The cephalochordate Amphioxus naturally co-expresses fluorescent proteins (FPs) with different brightness, which thus offers the rare opportunity to identify FP molecular feature/s that are associated with greater/lower intensity of fluorescence. Here, we describe the spectral and structural characteristics of green FP (bfloGFPa1) with perfect (100%) quantum efficiency yielding to unprecedentedly-high brightness, and compare them to those of co-expressed bfloGFPc1 showing extremely-dim brightness due to low (0.1%) quantum efficiency. This direct comparison of structure-function relationship indicated that in the bright bfloGFPa1, a Tyrosine (Tyr159) promotes a ring flipping of a Tryptophan (Trp157) that in turn allows a cis-trans transformation of a Proline (Pro55). Consequently, the FP chromophore is pushed up, which comes with a slight tilt and increased stability. FPs are continuously engineered for improved biochemical and/or photonic properties, and this study provides new insight to the challenge of establishing a clear mechanistic understanding between chromophore structural environment and brightness level.

  3. Spectral and structural comparison between bright and dim green fluorescent proteins in Amphioxus.

    PubMed

    Bomati, Erin K; Haley, Joy E; Noel, Joseph P; Deheyn, Dimitri D

    2014-01-01

    The cephalochordate Amphioxus naturally co-expresses fluorescent proteins (FPs) with different brightness, which thus offers the rare opportunity to identify FP molecular feature/s that are associated with greater/lower intensity of fluorescence. Here, we describe the spectral and structural characteristics of green FP (bfloGFPa1) with perfect (100%) quantum efficiency yielding to unprecedentedly-high brightness, and compare them to those of co-expressed bfloGFPc1 showing extremely-dim brightness due to low (0.1%) quantum efficiency. This direct comparison of structure-function relationship indicated that in the bright bfloGFPa1, a Tyrosine (Tyr159) promotes a ring flipping of a Tryptophan (Trp157) that in turn allows a cis-trans transformation of a Proline (Pro55). Consequently, the FP chromophore is pushed up, which comes with a slight tilt and increased stability. FPs are continuously engineered for improved biochemical and/or photonic properties, and this study provides new insight to the challenge of establishing a clear mechanistic understanding between chromophore structural environment and brightness level. PMID:24968921

  4. Fluorescent particles enable visualization of gas flow

    NASA Technical Reports Server (NTRS)

    Wilson, A. J.

    1968-01-01

    Fluorescent particles enable visualization of the flow patterns of gases at slow velocities. Through a transparent section in the gas line, a camera views the visible light emitted by the particles carried by the gas stream. Fine definition of the particle tracks are obtained at slow camera shutter speeds.

  5. Quantum dot blueing and blinking enables fluorescence nanoscopy.

    PubMed

    Hoyer, Patrick; Staudt, Thorsten; Engelhardt, Johann; Hell, Stefan W

    2011-01-12

    We demonstrate superresolution fluorescence imaging of cells using bioconjugated CdSe/ZnS quantum dot markers. Fluorescence blueing of quantum dot cores facilitates separation of blinking markers residing closer than the diffraction barrier. The high number of successively emitted photons enables ground state depletion microscopy followed by individual marker return with a resolving power of the size of a single dot (∼12 nm). Nanoscale imaging is feasible with a simple webcam.

  6. Chemical reactivation of quenched fluorescent protein molecules enables resin-embedded fluorescence microimaging

    NASA Astrophysics Data System (ADS)

    Xiong, Hanqing; Zhou, Zhenqiao; Zhu, Mingqiang; Lv, Xiaohua; Li, Anan; Li, Shiwei; Li, Longhui; Yang, Tao; Wang, Siming; Yang, Zhongqin; Xu, Tonghui; Luo, Qingming; Gong, Hui; Zeng, Shaoqun

    2014-06-01

    Resin embedding is a well-established technique to prepare biological specimens for microscopic imaging. However, it is not compatible with modern green-fluorescent protein (GFP) fluorescent-labelling technique because it significantly quenches the fluorescence of GFP and its variants. Previous empirical optimization efforts are good for thin tissue but not successful on macroscopic tissue blocks as the quenching mechanism remains uncertain. Here we show most of the quenched GFP molecules are structurally preserved and not denatured after routine embedding in resin, and can be chemically reactivated to a fluorescent state by alkaline buffer during imaging. We observe up to 98% preservation in yellow-fluorescent protein case, and improve the fluorescence intensity 11.8-fold compared with unprocessed samples. We demonstrate fluorescence microimaging of resin-embedded EGFP/EYFP-labelled tissue block without noticeable loss of labelled structures. This work provides a turning point for the imaging of fluorescent protein-labelled specimens after resin embedding.

  7. Chemical reactivation of quenched fluorescent protein molecules enables resin-embedded fluorescence microimaging

    PubMed Central

    Xiong, Hanqing; Zhou, Zhenqiao; Zhu, Mingqiang; Lv, Xiaohua; Li, Anan; Li, Shiwei; Li, Longhui; Yang, Tao; Wang, Siming; Yang, Zhongqin; Xu, Tonghui; Luo, Qingming; Gong, Hui; Zeng, Shaoqun

    2014-01-01

    Resin embedding is a well-established technique to prepare biological specimens for microscopic imaging. However, it is not compatible with modern green-fluorescent protein (GFP) fluorescent-labelling technique because it significantly quenches the fluorescence of GFP and its variants. Previous empirical optimization efforts are good for thin tissue but not successful on macroscopic tissue blocks as the quenching mechanism remains uncertain. Here we show most of the quenched GFP molecules are structurally preserved and not denatured after routine embedding in resin, and can be chemically reactivated to a fluorescent state by alkaline buffer during imaging. We observe up to 98% preservation in yellow-fluorescent protein case, and improve the fluorescence intensity 11.8-fold compared with unprocessed samples. We demonstrate fluorescence microimaging of resin-embedded EGFP/EYFP-labelled tissue block without noticeable loss of labelled structures. This work provides a turning point for the imaging of fluorescent protein-labelled specimens after resin embedding. PMID:24886825

  8. Enabling in situ thermometry using transmission nuclear resonance fluorescence

    NASA Astrophysics Data System (ADS)

    Angell, Christopher T.

    2016-02-01

    Transmission nuclear resonance fluorescence (NRF) has been proposed for use as an assay and detection technique for nuclear security and safeguards applications because of its isotope-specific sensitivity and the penetrating capability of γ -rays. It can also be used for in situ thermometry because the absorbing resonance profile is sensitive to temperature. Using transmission NRF for thermometry could provide a new avenue for studying the ion temperature evolution of laser-induced plasmas using the upcoming ELI-NP facility. It could also be used for applications where thermometry would be otherwise infeasible, such as for determining the average fuel temperature of spent nuclear fuel, a step that would reduce the assay uncertainty using transmission NRF. In this paper, two different transmission NRF thermometry scenarios are presented and analyzed for sensitivity. This analysis demonstrated that thermometry using γ -rays is possible independent of γ -ray beam type and will be feasible with next-generation high-intensity γ -ray sources. Beyond thermometry, an application of temperature effects was found in the improvement of transmission NRF efficacy for assay and detection: using a cryogenic witness target will reduce the required measurement time by 40%.

  9. Enabling fluorescent biosensors for the forensic identification of body fluids.

    PubMed

    Frascione, Nunzianda; Gooch, James; Daniel, Barbara

    2013-11-12

    The search for body fluids often forms a crucial element of many forensic investigations. Confirming fluid presence at a scene can not only support or refute the circumstantial claims of a victim, suspect or witness, but may additionally provide a valuable source of DNA for further identification purposes. However, current biological fluid testing techniques are impaired by a number of well-characterised limitations; they often give false positives, cannot be used simultaneously, are sample destructive and lack the ability to visually locate fluid depositions. These disadvantages can negatively affect the outcome of a case through missed or misinterpreted evidence. Biosensors are devices able to transduce a biological recognition event into a measurable signal, resulting in real-time analyte detection. The use of innovative optical sensing technology may enable the highly specific and non-destructive detection of biological fluid depositions through interaction with several fluid-endogenous biomarkers. Despite considerable impact in a variety of analytical disciplines, biosensor application within forensic analyses may be considered extremely limited. This article aims to explore a number of prospective biosensing mechanisms and to outline the challenges associated with their adaptation towards detection of fluid-specific analytes.

  10. Fluorescence resonance energy transfer between green fluorescent protein and doxorubicin enabled by DNA nanotechnology.

    PubMed

    Heger, Zbynek; Kominkova, Marketa; Cernei, Natalia; Krejcova, Ludmila; Kopel, Pavel; Zitka, Ondrej; Adam, Vojtech; Kizek, Rene

    2014-12-01

    DNA nanotechnology is a rapidly growing research area, where DNA may be used for wide range of applications such as construction of nanodevices serving for large scale of diverse purposes. Likewise a panel of various purified fluorescent proteins is investigated for their ability to emit their typical fluorescence spectra under influence of particular excitation. Hence these proteins may form ideal donor molecules for assembly of fluorescence resonance emission transfer (FRET) constructions. To extend the application possibilities of fluorescent proteins, while using DNA nanotechnology, we developed nanoconstruction comprising green fluorescent protein (GFP) bound onto surface of surface active nanomaghemite and functionalized with gold nanoparticles. We took advantage of natural affinity between gold and thiol moieties, which were modified to bind DNA fragment. Finally we enclosed doxorubicin into fullerene cages. Doxorubicin intercalated in DNA fragment bound on the particles and thus we were able to connect these parts together. Because GFP behaved as a donor and doxorubicin as an acceptor using excitation wavelength for GFP (395 nm) in emission wavelength of doxorubicin (590 nm) FRET was observed. This nanoconstruction may serve as a double-labeled transporter of doxorubicin guided by force of external magnetic force owing to the presence of nanomaghemite. Further nanomaghemite offers the possibility of using this technology for thermotherapy.

  11. Rearview Mirror Dimming Function

    ERIC Educational Resources Information Center

    Layton, William

    2011-01-01

    Students are often unaware of the little tab on a rear-view mirror that is used to dim headlights from the rear. Those who know about this tab are usually interested in knowing how it works. Explanations of the optics involved can be found in Serway and Jewett and Jones and Edge. An alternate explanation is given.

  12. Rearview Mirror Dimming Function

    NASA Astrophysics Data System (ADS)

    Layton, William

    2011-12-01

    Students are often unaware of the little tab on a rear-view mirror that is used to dim headlights from the rear. Those who know about this tab are usually interested in knowing how it works. Explanations of the optics involved can be found in Serway and Jewett and Jones and Edge.2 An alternate explanation is given below:

  13. Hyperspectral Microscopy of Near-Infrared Fluorescence Enables 17-Chirality Carbon Nanotube Imaging

    PubMed Central

    Roxbury, Daniel; Jena, Prakrit V.; Williams, Ryan M.; Enyedi, Balázs; Niethammer, Philipp; Marcet, Stéphane; Verhaegen, Marc; Blais-Ouellette, Sébastien; Heller, Daniel A.

    2015-01-01

    The intrinsic near-infrared photoluminescence (fluorescence) of single-walled carbon nanotubes exhibits unique photostability, narrow bandwidth, penetration through biological media, environmental sensitivity, and both chromatic variety and range. Biomedical applications exploiting this large family of fluorophores will require the spectral and spatial resolution of individual (n,m) nanotube species’ fluorescence and its modulation within live cells and tissues, which is not possible with current microscopy methods. We present a wide-field hyperspectral approach to spatially delineate and spectroscopically measure single nanotube fluorescence in living systems. This approach resolved up to 17 distinct (n,m) species (chiralities) with single nanotube spatial resolution in live mammalian cells, murine tissues ex vivo, and zebrafish endothelium in vivo. We anticipate that this approach will facilitate multiplexed nanotube imaging in biomedical applications while enabling deep-tissue optical penetration, and single-molecule resolution in vivo. PMID:26387482

  14. Stable J-aggregation enabled dual photoacoustic and fluorescence nanoparticles for intraoperative cancer imaging.

    PubMed

    Shakiba, Mojdeh; Ng, Kenneth K; Huynh, Elizabeth; Chan, Harley; Charron, Danielle M; Chen, Juan; Muhanna, Nidal; Foster, F Stuart; Wilson, Brian C; Zheng, Gang

    2016-07-01

    J-aggregates display nanoscale optical properties which enable their use in fluorescence and photoacoustic imaging applications. However, control over their optical properties in an in vivo setting is hampered by the conformational lability of the J-aggregate structure in complex biological environments. J-aggregating nanoparticles (JNP) formed by self-assembly of bacteriopheophorbide-lipid (Bchl-lipid) in lipid nanovesicles represents a novel strategy to stabilize J-aggregates for in vivo bioimaging applications. We find that 15 mol% Bchl-lipid embedded within a saturated phospholipid bilayer vesicle was optimal in terms of maximizing Bchl-lipid dye loading, while maintaining a spherical nanoparticle morphology and retaining spectral properties characteristic of J-aggregates. The addition of cholesterol maintains the stability of the J-aggregate absorption band for up to 6 hours in the presence of 90% FBS. In a proof-of-concept experiment, we successfully applied JNPs as a fluorescence contrast agent for real-time intraoperative detection of metastatic lymph nodes in a rabbit head-and-neck cancer model. Lymph node metastasis delineation was further verified by visualizing the JNP within the excised lymph node using photoacoustic imaging. Using JNPs, we demonstrate the possibility of using J-aggregates as fluorescence and photoacoustic contrast agents and may potentially spur the development of other nanomaterials that can stably induce J-aggregation for in vivo cancer bioimaging applications.

  15. EUV Dimmings: Simple or Enigmatic?

    NASA Technical Reports Server (NTRS)

    Thompson, B. J.; Biesecker, D. A.; Ofman, L.; SaintCyr, O. C.; Wills-Davey, M. J.

    2002-01-01

    EUV dimmings are large-scale depletions in coronal EUV emission associated with coronal mass ejections. Their occurrence is nearly 100% correlated with fast CMEs. Many of the EUV dimming observations appear to correspond well in appearance and behavior to SXR dimmings. It has been assumed that the dimmings are merely the location of the CME mass removal in the corona, and that their similar appearance to coronal holes is because they are transient coronal holes with fieldlines opened by the coronal mass ejection. However, not all CMEs have dimmings, and large-scale E W dimmings have also been caused by heating of local plasma, and due to absorption by cool material "clouds" evolving in the wake of an eruption. Additionally, there are several ways in which these regions "heal," presumably due to the closing down of the open field lines. The presentation will include a range of EUV dimming observations, a discussion of their origin, and what they might imply about the nature of the associated CMEs.

  16. Stable J-aggregation enabled dual photoacoustic and fluorescence nanoparticles for intraoperative cancer imaging

    NASA Astrophysics Data System (ADS)

    Shakiba, Mojdeh; Ng, Kenneth K.; Huynh, Elizabeth; Chan, Harley; Charron, Danielle M.; Chen, Juan; Muhanna, Nidal; Foster, F. Stuart; Wilson, Brian C.; Zheng, Gang

    2016-06-01

    J-aggregates display nanoscale optical properties which enable their use in fluorescence and photoacoustic imaging applications. However, control over their optical properties in an in vivo setting is hampered by the conformational lability of the J-aggregate structure in complex biological environments. J-aggregating nanoparticles (JNP) formed by self-assembly of bacteriopheophorbide-lipid (Bchl-lipid) in lipid nanovesicles represents a novel strategy to stabilize J-aggregates for in vivo bioimaging applications. We find that 15 mol% Bchl-lipid embedded within a saturated phospholipid bilayer vesicle was optimal in terms of maximizing Bchl-lipid dye loading, while maintaining a spherical nanoparticle morphology and retaining spectral properties characteristic of J-aggregates. The addition of cholesterol maintains the stability of the J-aggregate absorption band for up to 6 hours in the presence of 90% FBS. In a proof-of-concept experiment, we successfully applied JNPs as a fluorescence contrast agent for real-time intraoperative detection of metastatic lymph nodes in a rabbit head-and-neck cancer model. Lymph node metastasis delineation was further verified by visualizing the JNP within the excised lymph node using photoacoustic imaging. Using JNPs, we demonstrate the possibility of using J-aggregates as fluorescence and photoacoustic contrast agents and may potentially spur the development of other nanomaterials that can stably induce J-aggregation for in vivo cancer bioimaging applications.J-aggregates display nanoscale optical properties which enable their use in fluorescence and photoacoustic imaging applications. However, control over their optical properties in an in vivo setting is hampered by the conformational lability of the J-aggregate structure in complex biological environments. J-aggregating nanoparticles (JNP) formed by self-assembly of bacteriopheophorbide-lipid (Bchl-lipid) in lipid nanovesicles represents a novel strategy to stabilize J

  17. Field Commissioning of a Daylight-Dimming Lighting System.

    ERIC Educational Resources Information Center

    Floyd, David B.; Parker, Danny S.

    A Florida elementary school cafeteria, retrofitted with a fluorescent lighting system that dims in response to available daylight, was evaluated through real time measurement of lighting and air conditioning power, work plane illumination, and interior/exterior site conditions. The new system produced a 27 percent reduction in lighting power due…

  18. Imaging transient formation of diffusion layers with fluorescence-enabled electrochemical microscopy.

    PubMed

    Oja, Stephen M; Zhang, Bo

    2014-12-16

    Fluorescence-enabled electrochemical microscopy (FEEM) is demonstrated as a new technique to image transient concentration profiles of redox species generated on ultramicroelectrodes (UMEs). FEEM converts an electrical signal into an optical signal by electrically coupling a conventional redox reaction to a fluorogenic reporter reaction on a closed bipolar electrode. We describe the implementation of FEEM for diffusion layer imaging and use an array of thousands of parallel bipolar electrodes to image the diffusion layers of UMEs in two and three dimensions. This new technique provides a way to image an entire 2-dimensional lateral cross section of a dynamic diffusion layer in a single experiment. By taking several of these lateral cross sections at different axial positions in the diffusion layer, a 3-dimensional image of the diffusion layer can be built. We image the diffusion layer of a 10 μm diameter carbon fiber electrode over the course of a cyclic voltammetry experiment and compare the FEEM-generated images to concentration profiles generated from numerical simulation. We also image the diffusion layer of a two electrode array consisting of two 10 μm diameter carbon fibers over the course of a potential step experiment.

  19. Optically sectioned wide-field fluorescence lifetime imaging endoscopy enabled by structured illumination (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Hinsdale, Taylor; Malik, Bilal H.; Rico-Jimenez, Jose J.; Jo, Javier A.; Maitland, Kristen C.

    2016-03-01

    We present a wide-field fluorescence lifetime imaging (FLIM) system with optical sectioning by structured illumination microscopy (SIM). FLIM measurements were made using a time gated ICCD camera in conjunction with a pulsed nitrogen dye laser operating at 450 nm. Intensity images were acquired at multiple time delays from a trigger initiated by a laser pulse to create a wide-field FLIM image, which was then combined with three phase SIM to provide optical sectioning. Such a mechanism has the potential to increase the reliability and accuracy of the FLIM measurements by rejecting background intensity. SIM also provides the opportunity to create volumetric FLIM images with the incorporation of scanning mechanisms for the sample plane. We present multiple embodiments of such a system: one as a free space endoscope and the other as a fiber microendoscope enabled by the introduction of a fiber bundle. Finally, we demonstrate the efficacy of such an imaging system by imaging dyes embedded in a tissue phantom.

  20. Single-Chromophore-Based Photoswitchable Nanoparticles Enable Dual-Alternating-Color Fluorescence for Unambiguous Live Cell Imaging

    PubMed Central

    Tian, Zhiyuan; Wu, Wuwei; Wan, Wei; Li, Alexander D. Q.

    2009-01-01

    We have developed a class of spiropyran dyes and their fluorescence colors can be reversibly photoswitched from red color to green, blue, or nearly dark, thus alternating between two colors. Such individual dyes emit either one color or the other, but not both simultaneously. These photoswitchable dyes-enabled nanoparticles, however, emit either one pure color or a combination of both colors because the nanoparticle fluorescence originates from multiple dyes therein. As a result, the nanoparticle shines >30 times brighter than the state-of-the-art organic dyes such as fluorescein. Interestingly, these copolymer nanoparticles exhibit tunable non-specific interactions with live cells and nanoparticles containing properly balanced butyl acrylate and acrylamide monomers render essentially very little non-specific binding to live cells. Decorated with HMGA1 protein, these optically switchable dual-color nanoparticles undergo endocytosis and unambiguously identify themselves from fluorescence interference including autofluorescence, thus enabling a new tool for live cell imaging. PMID:19275146

  1. Long-term reduction in bladder cancer recurrence with hexaminolevulinate enabled fluorescence cystoscopy

    PubMed Central

    Grossman, H. Barton; Stenzl, Arnulf; Fradet, Yves; Mynderse, Lance A.; Kriegmair, Martin; Witjes, J. Alfred; Soloway, Mark S.; Karl, Alexander; Burger, Maximilian

    2012-01-01

    Purpose We assessed the impact that hexaminolevulinate fluorescence cystoscopic detection of papillary, non-muscle invasive bladder cancer has on long-term recurrence rates. Materials and Methods Long-term follow-up was assessed in 551 participants enrolled in a prospective, randomized study of fluorescence cystoscopy for Ta or T1 urothelial bladder cancer. In the original study, 280 patients in the white light cystoscopy group and 271 in the fluorescence cystoscopy group were followed with cystoscopy for 3, 6, and 9 months following the initial resection or until recurrence. A study extension protocol obtained long-term follow-up of these patients. Results Follow-up information was obtained for 261 of the 280 (93%) participants in the white light group and 255 of the 271 (94%) participants in the fluorescence group. Median follow-up in the white light and fluorescence groups were 53.0 and 55.1 months, respectively. In the white light and fluorescence groups, 83 (31.8%) and 97 (38%) of the participants remained tumor free, respectively. The median recurrence free survival was 9.6 months in the white light group and 16.4 months in the fluorescence group, p = 0.04. The rates of intravesical therapy were similar in the white light (46%) and fluorescence groups (45%). Cystectomy was performed in 22/280 (7.9%) in the white light group and 13/271 (4.8%) in the fluorescence group, p = 0.16. Conclusions Hexaminolevulinate fluorescence cystoscopy significantly improves long-term bladder cancer recurrence free survival with a trend towards improved bladder preservation. PMID:22583635

  2. DIMMING OF THE 17TH CENTURY SUN

    SciTech Connect

    Foukal, Peter; Ortiz, Ada; Schnerr, Roald

    2011-06-01

    Reconstructions of total solar irradiance (TSI) rely mainly on linear relations between TSI variation and indices of facular area. When these are extrapolated to the prolonged 15th-17th century Spoerer and Maunder solar activity minima, the estimated solar dimming is insufficient to explain the mid-millennial climate cooling of the Little Ice Age. We draw attention here to evidence that the relation departs from linearity at the lowest activity levels. Imaging photometry and radiometry indicate an increased TSI contribution per unit area from small network faculae by a factor of 2-4 compared with larger faculae in and around active regions. Even partial removal of this more TSI-effective network at prolonged minima could enable climatically significant solar dimming, yet be consistent with the weakened but persistent 11 yr cycle observed in Be 10 during the Maunder Minimum. The mechanism we suggest would not alter previous findings that increased solar radiative forcing is insufficient to account for 20th century global warming.

  3. A two-photon ratiometric fluorescent probe enables spatial coordinates determination of intracellular pH.

    PubMed

    Wang, Junjie; Sun, Yuming; Zhang, Weijia; Liu, Yong; Yu, Xiaoqiang; Zhao, Ning

    2014-11-01

    We reported a two-photon ratiometric fluorescent probe for detecting intracellular pH. When excited with 800 nm laser, an optimal output of laser as the routine equipment of two-photon fluorescence microscopy, the two-photon excited fluorescence of this probe showed distinct emission peak shift as large as 109 nm upon the change of pH values in vitro. Very importantly, the experiment results show that this probe has large two-photon absorption cross-section at pH 4.5 at 800 nm of 354 g, which ranks it as one of the best two-photon ratiometric fluorescent pH probes, and its working pH value is between 4.0 and 8.0 which could fit the intracellular pH range. Moreover, utilizing this probe, the two-photon ratiometric fluorescent images in living cells have been obtained, and the spatial coordinates of intracellular pH can be mapped. At the same time, the probe also exhibited selectivity, photostability and membrane permeability. And the photophysical properties of this probe in various solvents indicated that these photophysical properties variations are due to an intramolecular charge transfer process. At last, the imaging depth of the probe in liver biopsy slices was investigated. The experimental results demonstrated the maximum imaging depth can arrive 66 µm in living rat liver tissues.

  4. Image reconstruction enables high resolution imaging at large penetration depths in fluorescence microscopy

    NASA Astrophysics Data System (ADS)

    Dilipkumar, Shilpa; Montalescot, Sandra; Mondal, Partha Pratim

    2013-10-01

    Imaging thick specimen at a large penetration depth is a challenge in biophysics and material science. Refractive index mismatch results in spherical aberration that is responsible for streaking artifacts, while Poissonian nature of photon emission and scattering introduces noise in the acquired three-dimensional image. To overcome these unwanted artifacts, we introduced a two-fold approach: first, point-spread function modeling with correction for spherical aberration and second, employing maximum-likelihood reconstruction technique to eliminate noise. Experimental results on fluorescent nano-beads and fluorescently coated yeast cells (encaged in Agarose gel) shows substantial minimization of artifacts. The noise is substantially suppressed, whereas the side-lobes (generated by streaking effect) drops by 48.6% as compared to raw data at a depth of 150 μm. Proposed imaging technique can be integrated to sophisticated fluorescence imaging techniques for rendering high resolution beyond 150 μm mark.

  5. Peptide-Conjugated Fluorescent Silicon Nanoparticles Enabling Simultaneous Tracking and Specific Destruction of Cancer Cells.

    PubMed

    Song, Chongxi; Zhong, Yiling; Jiang, Xiangxu; Peng, Fei; Lu, Yimei; Ji, Xiaoyuan; Su, Yuanyuan; He, Yao

    2015-07-01

    We herein introduce a kind of fluorescent silicon nanoparticles (SiNPs) bioprobes, that is, peptides-conjugated SiNPs, which simultaneously feature small sizes (<10 nm), biological functionality, and stable and strong fluorescence (photoluminescent quantum yield (PLQY): ∼28%), as well as favorable biocompatibility. Taking advantage of these merits, we further demonstrate such resultant SiNPs bioprobes are superbly suitable for real-time immunofluorescence imaging of cancer cells. Meanwhile, malignant tumor cells could be specifically destroyed by the peptides-conjugated SiNPs, suggesting potential promise of simultaneous detection and treatment of cancer cells.

  6. Fluorescence bimolecular complementation enables facile detection of ribosome assembly defects in Escherichia coli.

    PubMed

    Sharma, Himanshu; Anand, Baskaran

    2016-09-01

    Assembly factors promote the otherwise non-spontaneous maturation of ribosome under physiological conditions inside the cell. Systematic identification and characterization of candidate assembly factors are fraught with bottlenecks due to lack of facile assay system to capture assembly defects. Here, we show that bimolecular fluorescence complementation (BiFC) allows detection of assembly defects that are induced by the loss of assembly factors. The fusion of N and C-terminal fragments of Venus fluorescent protein to the ribosomal proteins uS13 and uL5, respectively, in Escherichia coli facilitated the incorporation of the tagged uS13 and uL5 onto the respective ribosomal subunits. When the ribosomal subunits associated to form the 70S particle, the complementary fragments of Venus were brought into proximity and rendered the Venus fluorescent. Assembly defects that inhibit the subunits association were provoked by either the loss of the known assembly factors such as RsgA and SrmB or the presence of small molecule inhibitors of ribosome maturation such as Lamotrigine and several ribosome-targeting antibiotics and these showed abrogation of the fluorescence complementation. This suggests that BiFC can be employed as a surrogate measure to detect ribosome assembly defects proficiently by circumventing the otherwise cumbersome procedures. BiFC thus offers a facile platform not only for systematic screening to validate potential assembly factors but also to discover novel small molecule inhibitors of ribosome assembly toward mapping the complex assembly landscape of ribosome.

  7. Topical MMP beacon enabled fluorescence-guided resection of oral carcinoma.

    PubMed

    Burgess, Laura; Chen, Juan; Wolter, Nikolaus E; Wilson, Brian; Zheng, Gang

    2016-03-01

    Each year almost 300,000 individuals worldwide are diagnosed with oral cancer, more than 90% of these being oral carcinoma [N. Engl. J. Med.328, 1841993]. Surgical resection is the standard of care, but accurate delineation of the tumor boundaries is challenging, resulting in either under-resection with risk of local recurrence or over-resection with increased functional loss and negative impact on quality of life. This study evaluates, in two pre-clinical in vivo tumor models, the potential of fluorescence-guided resection using molecular beacons activated by metalloproteinases, which are frequently upregulated in human oral cancer. In both models there was rapid (<15 min) beacon activation upon local application, allowing clear fluoresecence imaging in vivo and confirmed by ex vivo fluorescence microscopy and HPLC, with minimal activation in normal oral tissues. Although the tissue penetration was limited using topical application, these findings support further development of this approach towards translation to first-in-human trials.

  8. Fluorescence bimolecular complementation enables facile detection of ribosome assembly defects in Escherichia coli.

    PubMed

    Sharma, Himanshu; Anand, Baskaran

    2016-09-01

    Assembly factors promote the otherwise non-spontaneous maturation of ribosome under physiological conditions inside the cell. Systematic identification and characterization of candidate assembly factors are fraught with bottlenecks due to lack of facile assay system to capture assembly defects. Here, we show that bimolecular fluorescence complementation (BiFC) allows detection of assembly defects that are induced by the loss of assembly factors. The fusion of N and C-terminal fragments of Venus fluorescent protein to the ribosomal proteins uS13 and uL5, respectively, in Escherichia coli facilitated the incorporation of the tagged uS13 and uL5 onto the respective ribosomal subunits. When the ribosomal subunits associated to form the 70S particle, the complementary fragments of Venus were brought into proximity and rendered the Venus fluorescent. Assembly defects that inhibit the subunits association were provoked by either the loss of the known assembly factors such as RsgA and SrmB or the presence of small molecule inhibitors of ribosome maturation such as Lamotrigine and several ribosome-targeting antibiotics and these showed abrogation of the fluorescence complementation. This suggests that BiFC can be employed as a surrogate measure to detect ribosome assembly defects proficiently by circumventing the otherwise cumbersome procedures. BiFC thus offers a facile platform not only for systematic screening to validate potential assembly factors but also to discover novel small molecule inhibitors of ribosome assembly toward mapping the complex assembly landscape of ribosome. PMID:27388791

  9. Two-photon excited fluorescence of intrinsic fluorophores enables label-free assessment of adipose tissue function

    PubMed Central

    Alonzo, Carlo Amadeo; Karaliota, Sevasti; Pouli, Dimitra; Liu, Zhiyi; Karalis, Katia P.; Georgakoudi, Irene

    2016-01-01

    Current methods for evaluating adipose tissue function are destructive or have low spatial resolution. These limit our ability to assess dynamic changes and heterogeneous responses that occur in healthy or diseased subjects, or during treatment. Here, we demonstrate that intrinsic two-photon excited fluorescence enables functional imaging of adipocyte metabolism with subcellular resolution. Steady-state and time-resolved fluorescence from intracellular metabolic co-factors and lipid droplets can distinguish the functional states of excised white, brown, and cold-induced beige fat. Similar optical changes are identified when white and brown fat are assessed in vivo. Therefore, these studies establish the potential of non-invasive, high resolution, endogenous contrast, two-photon imaging to identify distinct adipose tissue types, monitor their functional state, and characterize heterogeneity of induced responses. PMID:27491409

  10. Two-photon excited fluorescence of intrinsic fluorophores enables label-free assessment of adipose tissue function

    NASA Astrophysics Data System (ADS)

    Alonzo, Carlo Amadeo; Karaliota, Sevasti; Pouli, Dimitra; Liu, Zhiyi; Karalis, Katia P.; Georgakoudi, Irene

    2016-08-01

    Current methods for evaluating adipose tissue function are destructive or have low spatial resolution. These limit our ability to assess dynamic changes and heterogeneous responses that occur in healthy or diseased subjects, or during treatment. Here, we demonstrate that intrinsic two-photon excited fluorescence enables functional imaging of adipocyte metabolism with subcellular resolution. Steady-state and time-resolved fluorescence from intracellular metabolic co-factors and lipid droplets can distinguish the functional states of excised white, brown, and cold-induced beige fat. Similar optical changes are identified when white and brown fat are assessed in vivo. Therefore, these studies establish the potential of non-invasive, high resolution, endogenous contrast, two-photon imaging to identify distinct adipose tissue types, monitor their functional state, and characterize heterogeneity of induced responses.

  11. DIM and diagnostic placement for NIF experiments

    SciTech Connect

    Kalantar, D

    1999-09-14

    The input that has been provided on the NIF experiment setup sheets has allowed us to review the diagnostic and DIM placement as well as the baseline unconverted light management plan. We have done an iteration to identify common diagnostic lines of sight, and with additional requirements defined by specific experiments, we propose (1) a baseline plan for DIM placement requiring only five DIMs that may be moved between up to seven DIM ports, and (2) a modified baseline unconverted light management plan. We request additional input to identify primary vs. secondary diagnostics for each experiment definition.

  12. Topical MMP beacon enabled fluorescence-guided resection of oral carcinoma.

    PubMed

    Burgess, Laura; Chen, Juan; Wolter, Nikolaus E; Wilson, Brian; Zheng, Gang

    2016-03-01

    Each year almost 300,000 individuals worldwide are diagnosed with oral cancer, more than 90% of these being oral carcinoma [N. Engl. J. Med.328, 1841993]. Surgical resection is the standard of care, but accurate delineation of the tumor boundaries is challenging, resulting in either under-resection with risk of local recurrence or over-resection with increased functional loss and negative impact on quality of life. This study evaluates, in two pre-clinical in vivo tumor models, the potential of fluorescence-guided resection using molecular beacons activated by metalloproteinases, which are frequently upregulated in human oral cancer. In both models there was rapid (<15 min) beacon activation upon local application, allowing clear fluoresecence imaging in vivo and confirmed by ex vivo fluorescence microscopy and HPLC, with minimal activation in normal oral tissues. Although the tissue penetration was limited using topical application, these findings support further development of this approach towards translation to first-in-human trials. PMID:27231609

  13. Next-generation RNA-based fluorescent biosensors enable anaerobic detection of cyclic di-GMP

    PubMed Central

    Wang, Xin C.; Wilson, Stephen C.; Hammond, Ming C.

    2016-01-01

    Bacteria occupy a diverse set of environmental niches with differing oxygen availability. Anaerobic environments such as mammalian digestive tracts and industrial reactors harbor an abundance of both obligate and facultative anaerobes, many of which play significant roles in human health and biomanufacturing. Studying bacterial function under partial or fully anaerobic conditions, however, is challenging given the paucity of suitable live-cell imaging tools. Here, we introduce a series of RNA-based fluorescent biosensors that respond selectively to cyclic di-GMP, an intracellular bacterial second messenger that controls cellular motility and biofilm formation. We demonstrate the utility of these biosensors in vivo under both aerobic and anaerobic conditions, and we show that biosensor expression does not interfere with the native motility phenotype. Together, our results attest to the effectiveness and versatility of RNA-based fluorescent biosensors, priming further development and application of these and other analogous sensors to study host–microbial and microbial–microbial interactions through small molecule signals. PMID:27382070

  14. Next-generation RNA-based fluorescent biosensors enable anaerobic detection of cyclic di-GMP.

    PubMed

    Wang, Xin C; Wilson, Stephen C; Hammond, Ming C

    2016-09-30

    Bacteria occupy a diverse set of environmental niches with differing oxygen availability. Anaerobic environments such as mammalian digestive tracts and industrial reactors harbor an abundance of both obligate and facultative anaerobes, many of which play significant roles in human health and biomanufacturing. Studying bacterial function under partial or fully anaerobic conditions, however, is challenging given the paucity of suitable live-cell imaging tools. Here, we introduce a series of RNA-based fluorescent biosensors that respond selectively to cyclic di-GMP, an intracellular bacterial second messenger that controls cellular motility and biofilm formation. We demonstrate the utility of these biosensors in vivo under both aerobic and anaerobic conditions, and we show that biosensor expression does not interfere with the native motility phenotype. Together, our results attest to the effectiveness and versatility of RNA-based fluorescent biosensors, priming further development and application of these and other analogous sensors to study host-microbial and microbial-microbial interactions through small molecule signals.

  15. Focal switching of photochromic fluorescent proteins enables multiphoton microscopy with superior image contrast

    PubMed Central

    Kao, Ya-Ting; Zhu, Xinxin; Xu, Fang; Min, Wei

    2012-01-01

    Probing biological structures and functions deep inside live organisms with light is highly desirable. Among the current optical imaging modalities, multiphoton fluorescence microscopy exhibits the best contrast for imaging scattering samples by employing a spatially confined nonlinear excitation. However, as the incident laser power drops exponentially with imaging depth into the sample due to the scattering loss, the out-of-focus background eventually overwhelms the in-focus signal, which defines a fundamental imaging-depth limit. Herein we significantly improve the image contrast for deep scattering samples by harnessing reversibly switchable fluorescent proteins (RSFPs) which can be cycled between bright and dark states upon light illumination. Two distinct techniques, multiphoton deactivation and imaging (MPDI) and multiphoton activation and imaging (MPAI), are demonstrated on tissue phantoms labeled with Dronpa protein. Such a focal switch approach can generate pseudo background-free images. Conceptually different from wave-based approaches that try to reduce light scattering in turbid samples, our work represents a molecule-based strategy that focused on imaging probes. PMID:22876358

  16. Next-generation RNA-based fluorescent biosensors enable anaerobic detection of cyclic di-GMP.

    PubMed

    Wang, Xin C; Wilson, Stephen C; Hammond, Ming C

    2016-09-30

    Bacteria occupy a diverse set of environmental niches with differing oxygen availability. Anaerobic environments such as mammalian digestive tracts and industrial reactors harbor an abundance of both obligate and facultative anaerobes, many of which play significant roles in human health and biomanufacturing. Studying bacterial function under partial or fully anaerobic conditions, however, is challenging given the paucity of suitable live-cell imaging tools. Here, we introduce a series of RNA-based fluorescent biosensors that respond selectively to cyclic di-GMP, an intracellular bacterial second messenger that controls cellular motility and biofilm formation. We demonstrate the utility of these biosensors in vivo under both aerobic and anaerobic conditions, and we show that biosensor expression does not interfere with the native motility phenotype. Together, our results attest to the effectiveness and versatility of RNA-based fluorescent biosensors, priming further development and application of these and other analogous sensors to study host-microbial and microbial-microbial interactions through small molecule signals. PMID:27382070

  17. Dimming of metal halide lamps

    NASA Technical Reports Server (NTRS)

    Schurer, Kees

    1994-01-01

    We ran some tests on the effect of dimming of metal halide (MH) lamps upon the stability and the spectral quality of the light output. Lamps used were a new Philips lamp HPI-T 250W, a similar Philips lamp with a few thousand burning hours and a new Osram lamp HQI-T 250W/D. The ballast was a BBC type DJ 250/2KS, the starter a BAS TORGI type MZN 250 SE and the dimmer an Elstrom Control System type ERHQ-T 250. Power was derived from a Philips stabilizer, type PE 1602. Lamp output was monitored with a PAR meter. Spectra were taken at 100% and at 50% output as measured with the PAR meter. Lamps were allowed to stabilize at any setting for 30 minutes before measurements were made. Lamp manufacturers advise against dimming for fear of poor stability and intolerable changes of the spectrum. However, none of the lamps showed a decrease in stability, no flicker or wandering of the discharge, and the changes of the spectrum were not negligible, but certainly not dramatic. Lamps of either manufacture retain their white color, relative peak heights of spectral lines did shift, but no gaps in the spectrum occurred. Spectra taken at 50% with 30 minutes intervals coincided. Differences between the new and the older Philips lamp were noticeable, but not really significant.

  18. Novel implantable imaging system for enabling simultaneous multiplanar and multipoint analysis for fluorescence potentiometry in the visual cortex.

    PubMed

    Kobayashi, Takuma; Motoyama, Mayumi; Masuda, Hiroyuki; Ohta, Yasumi; Haruta, Makito; Noda, Toshihiko; Sasagawa, Kiyotaka; Tokuda, Takashi; Tamura, Hideki; Ishikawa, Yasuyuki; Shiosaka, Sadao; Ohta, Jun

    2012-01-01

    Techniques for fast, noninvasive measurement of neuronal excitability within a broad area will be of major importance for analyzing and understanding neuronal networks and animal behavior in neuroscience field. In this research, a novel implantable imaging system for fluorescence potentiometry was developed using a complementary metal-oxide semiconductor (CMOS) technology, and its application to the analysis of cultured brain slices and the brain of a living mouse is described. A CMOS image sensor, small enough to be implanted into the brain, with light-emitting diodes and an absorbing filter was developed to enable real-time fluorescence imaging. The sensor, in conjunction with a voltage-sensitive dye, was certainly able to visualize the potential statuses of neurons and obtain physiological responses in both right and left visual cortex simultaneously by using multiple sensors for the first time. This accomplished multiplanar and multipoint measurement provides multidimensional information from different aspects. The light microsensors do not disturb the animal behavior. This implies that the imaging system can combine functional fluorescence imaging in the brain with behavioral experiments in a freely moving animal.

  19. A Parallel Distributed-Memory Particle Method Enables Acquisition-Rate Segmentation of Large Fluorescence Microscopy Images

    PubMed Central

    Afshar, Yaser; Sbalzarini, Ivo F.

    2016-01-01

    Modern fluorescence microscopy modalities, such as light-sheet microscopy, are capable of acquiring large three-dimensional images at high data rate. This creates a bottleneck in computational processing and analysis of the acquired images, as the rate of acquisition outpaces the speed of processing. Moreover, images can be so large that they do not fit the main memory of a single computer. We address both issues by developing a distributed parallel algorithm for segmentation of large fluorescence microscopy images. The method is based on the versatile Discrete Region Competition algorithm, which has previously proven useful in microscopy image segmentation. The present distributed implementation decomposes the input image into smaller sub-images that are distributed across multiple computers. Using network communication, the computers orchestrate the collectively solving of the global segmentation problem. This not only enables segmentation of large images (we test images of up to 1010 pixels), but also accelerates segmentation to match the time scale of image acquisition. Such acquisition-rate image segmentation is a prerequisite for the smart microscopes of the future and enables online data compression and interactive experiments. PMID:27046144

  20. A Parallel Distributed-Memory Particle Method Enables Acquisition-Rate Segmentation of Large Fluorescence Microscopy Images.

    PubMed

    Afshar, Yaser; Sbalzarini, Ivo F

    2016-01-01

    Modern fluorescence microscopy modalities, such as light-sheet microscopy, are capable of acquiring large three-dimensional images at high data rate. This creates a bottleneck in computational processing and analysis of the acquired images, as the rate of acquisition outpaces the speed of processing. Moreover, images can be so large that they do not fit the main memory of a single computer. We address both issues by developing a distributed parallel algorithm for segmentation of large fluorescence microscopy images. The method is based on the versatile Discrete Region Competition algorithm, which has previously proven useful in microscopy image segmentation. The present distributed implementation decomposes the input image into smaller sub-images that are distributed across multiple computers. Using network communication, the computers orchestrate the collectively solving of the global segmentation problem. This not only enables segmentation of large images (we test images of up to 10(10) pixels), but also accelerates segmentation to match the time scale of image acquisition. Such acquisition-rate image segmentation is a prerequisite for the smart microscopes of the future and enables online data compression and interactive experiments.

  1. A Parallel Distributed-Memory Particle Method Enables Acquisition-Rate Segmentation of Large Fluorescence Microscopy Images.

    PubMed

    Afshar, Yaser; Sbalzarini, Ivo F

    2016-01-01

    Modern fluorescence microscopy modalities, such as light-sheet microscopy, are capable of acquiring large three-dimensional images at high data rate. This creates a bottleneck in computational processing and analysis of the acquired images, as the rate of acquisition outpaces the speed of processing. Moreover, images can be so large that they do not fit the main memory of a single computer. We address both issues by developing a distributed parallel algorithm for segmentation of large fluorescence microscopy images. The method is based on the versatile Discrete Region Competition algorithm, which has previously proven useful in microscopy image segmentation. The present distributed implementation decomposes the input image into smaller sub-images that are distributed across multiple computers. Using network communication, the computers orchestrate the collectively solving of the global segmentation problem. This not only enables segmentation of large images (we test images of up to 10(10) pixels), but also accelerates segmentation to match the time scale of image acquisition. Such acquisition-rate image segmentation is a prerequisite for the smart microscopes of the future and enables online data compression and interactive experiments. PMID:27046144

  2. Characteristics of EIT Dimmings in Solar Eruptions

    NASA Technical Reports Server (NTRS)

    Adams, Mitzi; Sterling, A. C.

    2006-01-01

    Intensity "dimmings" in coronal images are a key feature of solar eruptions. Such dimmings are likely the source locations for much of the material expelled in coronal mass ejections (CMEs). Characteristics such as the timing of the dimmings with respect to the onset of other eruption signatures, and the location of the dimmings in the context of the magnetic field environment of the erupting region, are indicative of the mechanism leading to the eruption. We examine dimmings of six eruptions in images from the EUV Imaging Telescope (EIT) on SOHO, along with supplementary soft X-ray (SXR) data from GOES and the SXR Telescope (SXT) on Yohkoh. We examine the timing of the dimming onset and compare with the time of EUV and SXR brightening and determine the timescale for the recovery from dimming for each event. With line-of-sight photospheric magnetograms from the MDI instrument on SOHO, we determine the magnetic structure of the erupting regions and the locations of the dimmings in those regions. From our analysis we consider which mechanism likely triggered each eruption: internal tether cutting, external tether cutting ("breakout"), loss of equilibrium, or some other mechanism.

  3. Tunable White Fluorescent Copper Gallium Sulfide Quantum Dots Enabled by Mn Doping.

    PubMed

    Jo, Dae-Yeon; Kim, Daekyoung; Kim, Jong-Hoon; Chae, Heeyeop; Seo, Hyo Jin; Do, Young Rag; Yang, Heesun

    2016-05-18

    Fluorescence of semiconductor quantum dots (QDs) can be tuned by engineering the band gap via size and composition control and further doping them with impurity ions. Targeting on highly bright white-emissive I-III-VI -type copper gallium sulfide (Cu-Ga-S, CGS) host QDs with the entire visible spectral coverage of blue to red, herein, Mn(2+) ion doping, through surface adsorption and lattice diffusion is fulfilled. Upon doping a distinct Mn emission from (4)T1-(6)A1 transition successfully appears in white photoluminescence (PL) of undoped CGS/ZnS core/shell QDs and with varying Mn concentration a systematic white spectral evolution of CGS:Mn/ZnS QDs is achievable with high PL quantum yield retained. The origins of white PL of CGS:Mn/ZnS QDs that is well decomposed into three emission bands are appropriately assigned. The resulting single-phased, doped QDs are then employed as near-UV-to-white down converters for the fabrication of white light-emitting diodes (LEDs). Electroluminescent properties of white QD-LEDs depending on Mn concentration of CGS:Mn/ZnS QDs and forward current are also discussed in detail. PMID:27120773

  4. Fluorescence Imaging Enabled Urethane-Doped Citrate-Based Biodegradable Elastomers

    PubMed Central

    Zhang, Yi; Tran, Richard T.; Qattan, Ibrahim; Tsai, Yi-ting; Tang, Liping; Liu, Chao; Yang, Jian

    2013-01-01

    The field of tissue engineering and drug delivery calls for new measurement tools, non-invasive real-time assays, and design methods for the next wave of innovations. Based on our recent progress in developing intrinsically biodegradable photoluminescent polymers (BPLPs) without conjugating organic dyes or quantum dots, in this paper, we developed a new type urethane-doped biodegradable photoluminescent polymers (UBPLPs) that could potentially serve as a new tool to respond the above call for innovations. Inherited from BPLPs, UBPLPs demonstrated strong inherent photoluminescence and excellent cytocompatibility in vitro. Crosslinked UBPLPs (CUBPLPs) showed soft, elastic, but strong mechanical properties with a tensile strength as high as 49.41±6.17 MPa and a corresponding elongation at break of 334.87±26.31%. Porous triphasic CUBPLP vascular scaffolds showed a burst pressure of 769.33±70.88 mmHg and a suture retention strength of 1.79±0.11 N. Stable but photoluminescent nanoparticles with average size of 103 nm were also obtained by nanoprecipitation. High loading efficiency (91.84%) and sustained release of 5-fluorouracil (up to 120 h) were achieved from UBPLP nanoparticles. With a quantum yield as high as 38.65%, both triphasic scaffold and nanoparticle solutions could be non-invasively detected in vivo. UBPLPs represent an innovation in fluorescent biomaterial design and may offer great potential in advancing the field of tissue engineering and drug delivery where bioimaging has gained increasing interest. PMID:23465824

  5. Tunable White Fluorescent Copper Gallium Sulfide Quantum Dots Enabled by Mn Doping.

    PubMed

    Jo, Dae-Yeon; Kim, Daekyoung; Kim, Jong-Hoon; Chae, Heeyeop; Seo, Hyo Jin; Do, Young Rag; Yang, Heesun

    2016-05-18

    Fluorescence of semiconductor quantum dots (QDs) can be tuned by engineering the band gap via size and composition control and further doping them with impurity ions. Targeting on highly bright white-emissive I-III-VI -type copper gallium sulfide (Cu-Ga-S, CGS) host QDs with the entire visible spectral coverage of blue to red, herein, Mn(2+) ion doping, through surface adsorption and lattice diffusion is fulfilled. Upon doping a distinct Mn emission from (4)T1-(6)A1 transition successfully appears in white photoluminescence (PL) of undoped CGS/ZnS core/shell QDs and with varying Mn concentration a systematic white spectral evolution of CGS:Mn/ZnS QDs is achievable with high PL quantum yield retained. The origins of white PL of CGS:Mn/ZnS QDs that is well decomposed into three emission bands are appropriately assigned. The resulting single-phased, doped QDs are then employed as near-UV-to-white down converters for the fabrication of white light-emitting diodes (LEDs). Electroluminescent properties of white QD-LEDs depending on Mn concentration of CGS:Mn/ZnS QDs and forward current are also discussed in detail.

  6. Dark Hydrazone Fluorescence Labeling Agents Enable Imaging of Cellular Aldehydic Load.

    PubMed

    Yuen, Lik Hang; Saxena, Nivedita S; Park, Hyun Shin; Weinberg, Kenneth; Kool, Eric T

    2016-08-19

    Aldehydes are key intermediates in many cellular processes, from endogenous metabolic pathways like glycolysis to undesired exogenously induced processes such as lipid peroxidation and DNA interstrand cross-linking. Alkyl aldehydes are well documented to be cytotoxic, affecting the functions of DNA and protein, and their levels are tightly regulated by the oxidative enzyme ALDH2. Mutations in this enzyme are associated with cardiac damage, diseases such as Fanconi anemia (FA), and cancer. Many attempts have been made to identify and quantify the overall level of these alkyl aldehydes inside cells, yet there are few practical methods available to detect and monitor these volatile aldehydes in real time. Here, we describe a multicolor fluorogenic hydrazone transfer ("DarkZone") system to label alkyl aldehydes, yielding up to 30-fold light-up response in vitro. A cell-permeant DarkZone dye design was applied to detect small-molecule aldehydes in the cellular environment. The new dye design also enabled the monitoring of cellular acetaldehyde production from ethanol over time by flow cytometry, demonstrating the utility of the DarkZone dyes for measuring and imaging the aldehydic load related to human disease. PMID:27326450

  7. Irving Langmuir Prize Talk: Single-Molecule Fluorescence Imaging: Nanoscale Emitters with Photoinduced Switching Enable Superresolution.

    NASA Astrophysics Data System (ADS)

    Moerner, W. E.

    2009-03-01

    In the two decades since the first optical detection and spectroscopy of a single molecule in a solid (Phys. Rev. Lett. 62, 2535 (1989)), much has been learned about the ability of single molecules to probe local nanoenvironments and individual behavior in biological and nonbiological materials in the absence of ensemble averaging that can obscure heterogeneity. The early years concentrated on high-resolution spectroscopy in solids, which provided observations of lifetime-limited spectra, optical saturation, spectral diffusion, optical switching, vibrational spectra, and magnetic resonance of a single molecular spin. In the mid-1990's, much of the field moved to room temperature, where a wide variety of biophysical effects were subsequently explored, but it is worth noting that several features from the low-temperature studies have analogs at high temperature. For example, in our first studies of yellow-emitting variants of green fluorescent protein (EYFP) in the water-filled pores of a gel (Nature 388, 355 (1997)), optically induced switching of the emission was observed, a room-temperature analog of the earlier low-temperature behavior. Because each single fluorophore acts a light source roughly 1 nm in size, microscopic imaging of individual fluorophores leads naturally to superlocalization, or determination of the position of the molecule with precision beyond the optical diffraction limit, simply by digitization of the point-spread function from the single emitter. Recent work has allowed measurement of the shape of single filaments in a living cell simply by allowing a single molecule to move through the filament (PNAS 103, 10929 (2006)). The additional use of photoinduced control of single-molecule emission allows imaging beyond the diffraction limit (superresolution) by several novel approaches proposed by different researchers. For example, using photoswitchable EYFP, a novel protein superstructure can now be directly imaged in a living bacterial cell at

  8. Vision Trouble Can Dim Life's Prospects

    MedlinePlus

    ... page: https://medlineplus.gov/news/fullstory_160136.html Vision Trouble Can Dim Life's Prospects But it's not ... THURSDAY, July 28, 2016 (HealthDay News) -- People with vision problems may face a higher risk of unemployment, ...

  9. A Fluorescent Transport Assay Enables Studying AmpG Permeases Involved in Peptidoglycan Recycling and Antibiotic Resistance.

    PubMed

    Perley-Robertson, G Evan; Yadav, Anuj K; Winogrodzki, Judith L; Stubbs, Keith A; Mark, Brian L; Vocadlo, David J

    2016-09-16

    Inducible AmpC β-lactamases deactivate a broad-spectrum of β-lactam antibiotics and afford antibiotic resistance in many Gram-negative bacteria. The disturbance of peptidoglycan recycling caused by β-lactam antibiotics leads to accumulation of GlcNAc-1,6-anhydroMurNAc-peptides, which are transported by AmpG to the cytoplasm where they are processed into AmpC inducers. AmpG transporters are poorly understood; however, their loss restores susceptibility toward β-lactam antibiotics, highlighting AmpG as a potential target for resistance-attenuating therapeutics. We prepare a GlcNAc-1,6-anhydroMurNAc-fluorophore conjugate and, using live E. coli spheroplasts, quantitatively analyze its transport by AmpG and inhibition of this process by a competing substrate. Further, we use this transport assay to evaluate the function of two AmpG homologues from Pseudomonas aeruginosa and show that P. aeruginosa AmpG (Pa-AmpG) but not AmpP (Pa-AmpP) transports this probe substrate. We corroborate these results by AmpC induction assays with Pa-AmpG and Pa-AmpP. This fluorescent AmpG probe and spheroplast-based transport assay will enable improved understanding of PG recycling and of permeases from the major facilitator superfamily of transport proteins and may aid in identification of AmpG antagonists that combat AmpC-mediated resistance toward β-lactam antibiotics.

  10. SYMPATHETIC FILAMENT ERUPTIONS CONNECTED BY CORONAL DIMMINGS

    SciTech Connect

    Jiang Yunchun; Yang Jiayan; Hong Junchao; Bi Yi; Zheng Ruisheng

    2011-09-10

    We present for the first time detailed observations of three successive, interdependent filament eruptions that occurred one by one within 5 hr from different locations beyond the range of a single active region. The first eruption was observed from an active region and was associated with a coronal mass ejection (CME), during which diffuse and complex coronal dimmings formed, largely extending to the two other filaments located in quiet-Sun regions. Then, both quiescent filaments consecutively underwent the second and third eruptions, while the nearby dimmings were persistent. Comparing the result of a derived coronal magnetic configuration, the magnetic connectivity between the dimmings suggested that they were caused by the joint effect of simple expansion of overlying loop systems forced by the first eruption, as well as by its erupting field interacting or reconnecting with the surrounding magnetic structures. Note that the dimming process in the first eruption indicated a weakening and partial removal of an overlying magnetic field constraint on the two other filaments, and thus one can physically connect these eruptions as sympathetic. It appears that the peculiar magnetic field configuration in our event was largely favorable to the occurrence of sympathetic filament eruptions. Because coronal dimmings are frequent and common phenomena in solar eruptions, especially in CME events, it is very likely that they represent a universal agent that can link consecutive eruptions nearby with sympathetic eruptions.

  11. Robust flicker evaluation method for low power adaptive dimming LCDs

    NASA Astrophysics Data System (ADS)

    Kim, Seul-Ki; Song, Seok-Jeong; Nam, Hyoungsik

    2015-05-01

    This paper describes a robust dimming flicker evaluation method of adaptive dimming algorithms for low power liquid crystal displays (LCDs). While the previous methods use sum of square difference (SSD) values without excluding the image sequence information, the proposed modified SSD (mSSD) values are obtained only with the dimming flicker effects by making use of differential images. The proposed scheme is verified for eight dimming configurations of two dimming level selection methods and four temporal filters over three test videos. Furthermore, a new figure of merit is introduced to cover the dimming flicker as well as image qualities and power consumption.

  12. Advanced dimming strategy for solid state luminaires

    NASA Astrophysics Data System (ADS)

    Beczkowski, Szymon

    2010-08-01

    Increased luminaire gamut as well as increase in luminous efficiency is found when the LED based luminaire is driven by a hybrid PWM/AM dimming technique. This technique is applicable to any n-chromaticity luminaire but it is especially suitable for trichromatic RGB luminaires that do not have inherent degrees of freedom. Diodes' properties under the hybrid dimming method were measured and used in nonlinear optimization routine to find the driving conditions that yield e.g. the highest possible efficacy for a given color point.

  13. Targeting the insulin growth factor-1 receptor with fluorescent antibodies enables high resolution imaging of human pancreatic cancer in orthotopic mouse models

    PubMed Central

    Park, Jeong Youp; Lee, Jin Young; Zhang, Yong; Hoffman, Robert M.; Bouvet, Michael

    2016-01-01

    The goal of the present study was to determine whether insulin-like growth factor-1 receptor (IGF-1R) antibodies, conjugated with bright fluorophores, could enable visualization of pancreatic cancer in orthotopic nude mouse models. IGF-1R antibody (clone 24-31) was conjugated with 550 nm or 650 nm fluorophores. Western blotting confirmed the expression of IGF-1R in Panc-1, BxPC3, and MIAPaCa-2 human pancreatic cancer cell lines. Labeling with fluorophore-conjugated IGF-1R antibody demonstrated fluorescent foci on the membrane of the pancreatic cancer cells. Subcutaneous Panc-1, BxPC-3, and MIA PaCa-2 tumors became fluorescent after intravenous administration of fluorescent IGF-1R antibodies. Orthotopically-transplanted BxPC-3 tumors became fluorescent with the conjugated IGF-1R antibodies, and were easily visible with intravital imaging. Gross and microscopic ex vivo imaging of resected pancreatic tumor and normal pancreas confirmed that fluorescence indeed came from the membrane of cancer cells, and it was stronger from the tumor than the normal tissue. The present study demonstrates that fluorophore-conjugated IGF-1R antibodies can visualize pancreatic cancer and it can be used with various imaging devices such as endoscopy and laparoscopy for diagnosis and fluorescence-guided surgery. PMID:26919100

  14. Quantitative fluorescence imaging enabled by spatial frequency domain optical-property mapping in the sub-diffusive regime for surgical guidance

    NASA Astrophysics Data System (ADS)

    Sibai, Mira; Veilleux, Israel; Elliott, Jonathan T.; Leblond, Frederic; Roberts, David W.; Wilson, Brian C.

    2015-03-01

    Intraoperative fluorescence guidance enables maximum safe resection of, for example, glioblastomas by providing surgeons with real-time tumor optical contrast. Specifically, 5-aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) fluorescence guided resection can improve surgical outcomes by better defining tumor margins and identifying satellite tumor foci. However, visual assessment of PpIX fluorescence is subjective and limited by the distorting effects of light attenuation (absorption and scattering) by tissue and background tissue autofluorescence. We have previously shown, using a point fluorescence-reflectance fiberoptic probe, that non-invasive measurement of the absolute PpIX concentration, [PpIX], further improves sensitivity and specificity, leading to the demonstration that the technique can also detect low-grade gliomas as well as otherwise undetectable residual tumor foci in high-grade disease. Here, we extend this approach to wide-field quantitative fluorescence imaging (qFI) by implementing spatial frequency domain imaging (SFDI) to recover the tissue optical absorption and transport scattering coefficients across the field of view. We report on the performance of this approach to determine the intrinsic fluorescence intensity in tissue-simulating phantoms in both the fully diffusive (i.e. scatter-dominated) and sub-diffusive (low transport albedo) regimes, for which higher spatial frequencies are used. The performance of qFI is compared to a Born- normalization correction scheme, as well as to the values obtained using the fiberoptic probe on homogeneous tissue phantoms containing PpIX.

  15. Photonic crystal fibre enables short-wavelength two-photon laser scanning fluorescence microscopy with fura-2

    NASA Astrophysics Data System (ADS)

    McConnell, Gail; Riis, Erling

    2004-10-01

    We report on a novel and compact reliable laser source capable of short-wavelength two-photon laser scanning fluorescence microscopy based on soliton self-frequency shift effects in photonic crystal fibre. We demonstrate the function of the system by performing two-photon microscopy of smooth muscle cells and cardiac myocytes from the rat pulmonary vein and Chinese hamster ovary cells loaded with the fluorescent calcium indicator fura-2/AM.

  16. Site-directed mutagenesis enabled preparation of a functional fluorescent analog of profilin: biochemical characterization and localization in living cells.

    PubMed

    Tarachandani, A; Wang, Y L

    1996-01-01

    The preparation of fluorescent profilin analogs for binding and spectroscopic studies, in vitro and in vivo, has been hampered by the poor chemical reactivity of this protein in its native form. We have addressed this problem by labeling a mutant, chemically reactive form of profilin. Site-directed mutagenesis was first used to replace a serine residue in a non-essential domain with a reactive cysteine residue. The mutant protein was expressed in Escherichia coli and reacted with tetramethylrhodamine iodoacetamide. In vitro assays indicated that the fluorescent profilin maintained its ability to bind actin, polyproline, and PIP2, to inhibit actin polymerization, and to stimulate actin nucleotide exchange. Fluorescence spectroscopy showed that neither the excitation nor the emission of the analog was sensitive to the interaction with actin or polyproline. However, binding of PIP2 caused a 75% quenching of the fluorescent signal, suggesting a dramatic change in the immediate environment of the probe. When the fluorescent profilin was microinjected into living NRK cells, it became localized at cell-cell junctions and discrete sites near the anterior end, where it colocalized with aggregates of unpolymerized actin. Different engineered forms of profilin with fluorophores located at defined sites should greatly facilitate the study of its interactions with various ligands and cellular structures.

  17. X-ray fluorescence analysis of soft materials using needle-type collimators enabling greater tolerance in analysis depth

    NASA Astrophysics Data System (ADS)

    Tsuji, Kouichi; Matsuda, Akinori; Nakano, Kazuhiko; Okhrimovskyy, Andriy

    2006-04-01

    A simple micro-X-ray fluorescence (XRF) method was proposed by using commercially available injection needles. Two needles were arranged in confocal configuration inside the sample. One injection needle, which was connected directly to an X-ray tube, was used as an X-ray guide to irradiate X-rays into the sample. Another needle, which was also inserted into the sample, was used to detect the X-ray fluorescence excited inside the sample. From the beam size, the analyzing volume was evaluated to be 0.24 mm 3. Therefore, the X-ray fluorescence emitted from a micro region inside the sample could be detected, although this method can only be applied for soft samples. It was demonstrated that the X-ray fluorescence of Zn in a gelatin sample could be measured, and a good linear relationship was obtained for this element. X-ray fluorescence from an oyster sample was also successfully measured by using the injection needles collimator system.

  18. Selective turn-on ammonia sensing enabled by high-temperature fluorescence in metal-organic frameworks with open metal sites.

    PubMed

    Shustova, Natalia B; Cozzolino, Anthony F; Reineke, Sebastian; Baldo, Marc; Dincă, Mircea

    2013-09-11

    We show that fluorescent molecules incorporated as ligands in rigid, porous metal-organic frameworks (MOFs) maintain their fluorescence response to a much higher temperature than in molecular crystals. The remarkable high-temperature ligand-based fluorescence, demonstrated here with tetraphenylethylene- and dihydroxyterephthalate-based linkers, is essential for enabling selective and rapid detection of analytes in the gas phase. Both Zn2(TCPE) (TCPE = tetrakis(4-carboxyphenyl)ethylene) and Mg(H2DHBDC) (H2DHBDC(2-) = 2,5-dihydroxybenzene-1,4-dicarboxylate) function as selective sensors for ammonia at 100 °C, although neither shows NH3 selectivity at room temperature. Variable-temperature diffuse-reflectance infrared spectroscopy, fluorescence spectroscopy, and X-ray crystallography are coupled with density-functional calculations to interrogate the temperature-dependent guest-framework interactions and the preferential analyte binding in each material. These results describe a heretofore unrecognized, yet potentially general property of many rigid, fluorescent MOFs and portend new applications for these materials in selective sensors, with selectivity profiles that can be tuned as a function of temperature.

  19. Selective turn-on ammonia sensing enabled by high-temperature fluorescence in metal-organic frameworks with open metal sites.

    PubMed

    Shustova, Natalia B; Cozzolino, Anthony F; Reineke, Sebastian; Baldo, Marc; Dincă, Mircea

    2013-09-11

    We show that fluorescent molecules incorporated as ligands in rigid, porous metal-organic frameworks (MOFs) maintain their fluorescence response to a much higher temperature than in molecular crystals. The remarkable high-temperature ligand-based fluorescence, demonstrated here with tetraphenylethylene- and dihydroxyterephthalate-based linkers, is essential for enabling selective and rapid detection of analytes in the gas phase. Both Zn2(TCPE) (TCPE = tetrakis(4-carboxyphenyl)ethylene) and Mg(H2DHBDC) (H2DHBDC(2-) = 2,5-dihydroxybenzene-1,4-dicarboxylate) function as selective sensors for ammonia at 100 °C, although neither shows NH3 selectivity at room temperature. Variable-temperature diffuse-reflectance infrared spectroscopy, fluorescence spectroscopy, and X-ray crystallography are coupled with density-functional calculations to interrogate the temperature-dependent guest-framework interactions and the preferential analyte binding in each material. These results describe a heretofore unrecognized, yet potentially general property of many rigid, fluorescent MOFs and portend new applications for these materials in selective sensors, with selectivity profiles that can be tuned as a function of temperature. PMID:23981174

  20. Mechanisms of the dimming and brightening aftereffects.

    PubMed

    Bosten, Jenny M; Macleod, Donald I A

    2013-01-01

    Dimming and brightening aftereffects occur after exposure to a temporal luminance sawtooth stimulus: A subsequently presented steady test field appears to become progressively dimmer or brighter, depending on the polarity of the adapting sawtooth. Although described as "dimming" and "brightening," it is plausible that a component of the aftereffects is based on contrast changes rather than on luminance changes. We conducted two experiments to reveal any contrast component. In the first we investigated whether the aftereffects result from the same mechanism that causes a polarity-selective loss in contrast sensitivity following luminance sawtooth adaptation. We manipulated test contrast: If a component of the aftereffect results from a polarity selective loss of contrast sensitivity we would expect that the aftereffects would differ in magnitude depending on the contrast polarity of the test fields. We found no effect of test-field polarity. In the second experiment we used an adapting sawtooth with a polarity consistent in contrast but alternating in luminance in order to induce a potential equivalent aftereffect of contrast. Again, we found no evidence that the aftereffects result from contrast adaptation. In a third experiment, we used S-cone isolating stimuli to discover whether there are S-cone dimming and brightening aftereffects. We found no aftereffects. However, in a fourth experiment we replicated Krauskopf and Zaidi's (1986) finding that adaptation to S-cone sawtooth stimuli affects thresholds for increment and decrement detection. The mechanism underlying the dimming and brightening aftereffects thus seems to be independent of the mechanism underlying the concurrent polarity selective reductions in contrast sensitivity.

  1. Bio-optimized energy transfer in densely packed fluorescent protein enables near-maximal luminescence and solid-state lasers

    NASA Astrophysics Data System (ADS)

    Gather, Malte C.; Yun, Seok Hyun

    2014-12-01

    Bioluminescent organisms are likely to have an evolutionary drive towards high radiance. As such, bio-optimized materials derived from them hold great promise for photonic applications. Here, we show that biologically produced fluorescent proteins retain their high brightness even at the maximum density in solid state through a special molecular structure that provides optimal balance between high protein concentration and low resonance energy transfer self-quenching. Dried films of green fluorescent protein show low fluorescence quenching (-7 dB) and support strong optical amplification (gnet=22 cm-1 96 dB cm-1). Using these properties, we demonstrate vertical cavity surface emitting micro-lasers with low threshold (<100 pJ, outperforming organic semiconductor lasers) and self-assembled all-protein ring lasers. Moreover, solid-state blends of different proteins support efficient Förster resonance energy transfer, with sensitivity to intermolecular distance thus allowing all-optical sensing. The design of fluorescent proteins may be exploited for bio-inspired solid-state luminescent molecules or nanoparticles.

  2. Bio-optimized energy transfer in densely packed fluorescent protein enables near-maximal luminescence and solid-state lasers.

    PubMed

    Gather, Malte C; Yun, Seok Hyun

    2014-12-08

    Bioluminescent organisms are likely to have an evolutionary drive towards high radiance. As such, bio-optimized materials derived from them hold great promise for photonic applications. Here, we show that biologically produced fluorescent proteins retain their high brightness even at the maximum density in solid state through a special molecular structure that provides optimal balance between high protein concentration and low resonance energy transfer self-quenching. Dried films of green fluorescent protein show low fluorescence quenching (-7 dB) and support strong optical amplification (gnet=22 cm(-1); 96 dB cm(-1)). Using these properties, we demonstrate vertical cavity surface emitting micro-lasers with low threshold (<100 pJ, outperforming organic semiconductor lasers) and self-assembled all-protein ring lasers. Moreover, solid-state blends of different proteins support efficient Förster resonance energy transfer, with sensitivity to intermolecular distance thus allowing all-optical sensing. The design of fluorescent proteins may be exploited for bio-inspired solid-state luminescent molecules or nanoparticles.

  3. Retail Lamps Study 3.1: Dimming, Flicker, and Power Quality Characteristics of LED A Lamps

    SciTech Connect

    Royer, Michael P.; Poplawski, Michael E.; Brown, Charles C.

    2014-12-01

    To date, all three reports in the retail lamps series have focused on basic performance parameters, such as lumen output, efficacy, and color quality. This report goes a step further, examining the photoelectric characteristics (i.e., dimming and flicker) of a subset of lamps from CALiPER Retails Lamps Study 3. Specifically, this report focuses on the dimming, power quality, and flicker characteristics of 14 LED A lamps, as controlled by four different retail-available dimmers. The results demonstrate notable variation across the various lamps, but little variation between the four dimmers. Overall, the LED lamps: ~tended to have higher relative light output compared to the incandescent and halogen benchmark at the same dimmer output signal (RMS voltage). The lamps’ dimming curves (i.e., the relationship between control signal and relative light output) ranged from linear to very similar to the square-law curve typical of an incandescent lamp. ~generally exhibited symmetrical behavior—the same dimming curve—when measured proceeding from maximum to minimum or minimum to maximum control signal. ~mostly dimmed below 10% of full light output, with some exceptions for specific lamp and dimmer combinations ~exhibited a range of flicker characteristics, with many comparing favorably to the level typical of a magnetically-ballasted fluorescent lamp through at least a majority of the dimming range. ~ always exceeded the relative (normalized) efficacy over the dimming range of the benchmark lamps, which rapidly decline in efficacy when they are dimmed. This report generally does not attempt to rank the performance of one product compared to another, but instead focuses on the collective performance of the group versus conventional incandescent or halogen lamps, the performance of which is likely to be the baseline for a majority of consumers. Undoubtedly, some LED lamps perform better—or more similar to conventional lamps—than others. Some perform desirably for one

  4. Fluorescent sensors for the basic metabolic panel enable measurement with a smart phone device over the physiological range.

    PubMed

    Awqatty, Becker; Samaddar, Shayak; Cash, Kevin J; Clark, Heather A; Dubach, J Matthew

    2014-10-21

    The advanced functionality of portable devices such as smart phones provides the necessary hardware to potentially perform complex diagnostic measurements in any setting. Recent research and development have utilized cameras and data acquisition properties of smart phones to create diagnostic approaches for a variety of diseases or pollutants. However, in concentration measurements, such as blood glucose, the performance of handheld diagnostic devices depends largely on the sensing mechanism. To expand measurements to multiple components, often necessary in medical tests, with a single diagnostic device, robust platform based sensors are needed. Here, we developed a suite of dual wavelength fluorescent sensors with response characteristics necessary to measure each component of a basic metabolic panel, a common clinical measurement. Furthermore, the response of these sensors could be measured with a simple optical setup to convert a smart phone into a fluorescence measurement instrument. This approach could be used as a mobile basic metabolic panel measurement system for point of care diagnostics.

  5. Two-color widefield fluorescence microendoscopy enables multiplexed molecular imaging in the alveolar space of human lung tissue

    NASA Astrophysics Data System (ADS)

    Krstajić, Nikola; Akram, Ahsan R.; Choudhary, Tushar R.; McDonald, Neil; Tanner, Michael G.; Pedretti, Ettore; Dalgarno, Paul A.; Scholefield, Emma; Girkin, John M.; Moore, Anne; Bradley, Mark; Dhaliwal, Kevin

    2016-04-01

    We demonstrate a fast two-color widefield fluorescence microendoscopy system capable of simultaneously detecting several disease targets in intact human ex vivo lung tissue. We characterize the system for light throughput from the excitation light emitting diodes, fluorescence collection efficiency, and chromatic focal shifts. We demonstrate the effectiveness of the instrument by imaging bacteria (Pseudomonas aeruginosa) in ex vivo human lung tissue. We describe a mechanism of bacterial detection through the fiber bundle that uses blinking effects of bacteria as they move in front of the fiber core providing detection of objects smaller than the fiber core and cladding (˜3 μm). This effectively increases the measured spatial resolution of 4 μm. We show simultaneous imaging of neutrophils, monocytes, and fungus (Aspergillus fumigatus) in ex vivo human lung tissue. The instrument has 10 nM and 50 nM sensitivity for fluorescein and Cy5 solutions, respectively. Lung tissue autofluorescence remains visible at up to 200 fps camera acquisition rate. The optical system lends itself to clinical translation due to high-fluorescence sensitivity, simplicity, and the ability to multiplex several pathological molecular imaging targets simultaneously.

  6. Two-color widefield fluorescence microendoscopy enables multiplexed molecular imaging in the alveolar space of human lung tissue

    NASA Astrophysics Data System (ADS)

    Krstajić, Nikola; Akram, Ahsan R.; Choudhary, Tushar R.; McDonald, Neil; Tanner, Michael G.; Pedretti, Ettore; Dalgarno, Paul A.; Scholefield, Emma; Girkin, John M.; Moore, Anne; Bradley, Mark; Dhaliwal, Kevin

    2016-04-01

    We demonstrate a fast two-color widefield fluorescence microendoscopy system capable of simultaneously detecting several disease targets in intact human ex vivo lung tissue. We characterize the system for light throughput from the excitation light emitting diodes, fluorescence collection efficiency, and chromatic focal shifts. We demonstrate the effectiveness of the instrument by imaging bacteria (Pseudomonas aeruginosa) in ex vivo human lung tissue. We describe a mechanism of bacterial detection through the fiber bundle that uses blinking effects of bacteria as they move in front of the fiber core providing detection of objects smaller than the fiber core and cladding (˜3 μm). This effectively increases the measured spatial resolution of 4 μm. We show simultaneous imaging of neutrophils, monocytes, and fungus (Aspergillus fumigatus) in ex vivo human lung tissue. The instrument has 10 nM and 50 nM sensitivity for fluorescein and Cy5 solutions, respectively. Lung tissue autofluorescence remains visible at up to 200 fps camera acquisition rate. The optical system lends itself to clinical translation due to high-fluorescence sensitivity, simplicity, and the ability to multiplex several pathological molecular imaging targets simultaneously.

  7. A Bright Fluorescent Probe for H2S Enables Analyte-Responsive, 3D Imaging in Live Zebrafish Using Light Sheet Fluorescence Microscopy

    PubMed Central

    2015-01-01

    Hydrogen sulfide (H2S) is a critical gaseous signaling molecule emerging at the center of a rich field of chemical and biological research. As our understanding of the complexity of physiological H2S in signaling pathways evolves, advanced chemical and technological investigative tools are required to make sense of this interconnectivity. Toward this goal, we have developed an azide-functionalized O-methylrhodol fluorophore, MeRho-Az, which exhibits a rapid >1000-fold fluorescence response when treated with H2S, is selective for H2S over other biological analytes, and has a detection limit of 86 nM. Additionally, the MeRho-Az scaffold is less susceptible to photoactivation than other commonly used azide-based systems, increasing its potential application in imaging experiments. To demonstrate the efficacy of this probe for H2S detection, we demonstrate the ability of MeRho-Az to detect differences in H2S levels in C6 cells and those treated with AOAA, a common inhibitor of enzymatic H2S synthesis. Expanding the use of MeRho-Az to complex and heterogeneous biological settings, we used MeRho-Az in combination with light sheet fluorescence microscopy (LSFM) to visualize H2S in the intestinal tract of live zebrafish. This application provides the first demonstration of analyte-responsive 3D imaging with LSFM, highlighting the utility of combining new probes and live imaging methods for investigating chemical signaling in complex multicellular systems. PMID:26061541

  8. A Bright Fluorescent Probe for H2S Enables Analyte-Responsive, 3D Imaging in Live Zebrafish Using Light Sheet Fluorescence Microscopy.

    PubMed

    Hammers, Matthew D; Taormina, Michael J; Cerda, Matthew M; Montoya, Leticia A; Seidenkranz, Daniel T; Parthasarathy, Raghuveer; Pluth, Michael D

    2015-08-19

    Hydrogen sulfide (H2S) is a critical gaseous signaling molecule emerging at the center of a rich field of chemical and biological research. As our understanding of the complexity of physiological H2S in signaling pathways evolves, advanced chemical and technological investigative tools are required to make sense of this interconnectivity. Toward this goal, we have developed an azide-functionalized O-methylrhodol fluorophore, MeRho-Az, which exhibits a rapid >1000-fold fluorescence response when treated with H2S, is selective for H2S over other biological analytes, and has a detection limit of 86 nM. Additionally, the MeRho-Az scaffold is less susceptible to photoactivation than other commonly used azide-based systems, increasing its potential application in imaging experiments. To demonstrate the efficacy of this probe for H2S detection, we demonstrate the ability of MeRho-Az to detect differences in H2S levels in C6 cells and those treated with AOAA, a common inhibitor of enzymatic H2S synthesis. Expanding the use of MeRho-Az to complex and heterogeneous biological settings, we used MeRho-Az in combination with light sheet fluorescence microscopy (LSFM) to visualize H2S in the intestinal tract of live zebrafish. This application provides the first demonstration of analyte-responsive 3D imaging with LSFM, highlighting the utility of combining new probes and live imaging methods for investigating chemical signaling in complex multicellular systems. PMID:26061541

  9. A Bright Fluorescent Probe for H2S Enables Analyte-Responsive, 3D Imaging in Live Zebrafish Using Light Sheet Fluorescence Microscopy.

    PubMed

    Hammers, Matthew D; Taormina, Michael J; Cerda, Matthew M; Montoya, Leticia A; Seidenkranz, Daniel T; Parthasarathy, Raghuveer; Pluth, Michael D

    2015-08-19

    Hydrogen sulfide (H2S) is a critical gaseous signaling molecule emerging at the center of a rich field of chemical and biological research. As our understanding of the complexity of physiological H2S in signaling pathways evolves, advanced chemical and technological investigative tools are required to make sense of this interconnectivity. Toward this goal, we have developed an azide-functionalized O-methylrhodol fluorophore, MeRho-Az, which exhibits a rapid >1000-fold fluorescence response when treated with H2S, is selective for H2S over other biological analytes, and has a detection limit of 86 nM. Additionally, the MeRho-Az scaffold is less susceptible to photoactivation than other commonly used azide-based systems, increasing its potential application in imaging experiments. To demonstrate the efficacy of this probe for H2S detection, we demonstrate the ability of MeRho-Az to detect differences in H2S levels in C6 cells and those treated with AOAA, a common inhibitor of enzymatic H2S synthesis. Expanding the use of MeRho-Az to complex and heterogeneous biological settings, we used MeRho-Az in combination with light sheet fluorescence microscopy (LSFM) to visualize H2S in the intestinal tract of live zebrafish. This application provides the first demonstration of analyte-responsive 3D imaging with LSFM, highlighting the utility of combining new probes and live imaging methods for investigating chemical signaling in complex multicellular systems.

  10. The Nature of CME-flare-Associated Coronal Dimming

    NASA Astrophysics Data System (ADS)

    Cheng, J. X.; Qiu, J.

    2016-07-01

    Coronal mass ejections (CMEs) are often accompanied by coronal dimming that is evident in extreme ultraviolet (EUV) and soft X-ray observations. The locations of dimming are sometimes considered to map footpoints of the erupting flux rope. As the emitting material expands in the corona, the decreased plasma density leads to reduced emission observed in spectral and irradiance measurements. Therefore, signatures of dimming may reflect the properties of CMEs in the early phase of their eruption. In this study, we analyze the event of flare, CME, and coronal dimming on 2011 December 26. We use the data from the Atmospheric Imaging Assembly on the Solar Dynamics Observatory for disk observations of the dimming, and analyze images taken by EUVI, COR1, and COR2 on board the Solar Terrestrial Relations Observatory to obtain the height and velocity of the associated CMEs observed at the limb. We also measure the magnetic reconnection rate from flare observations. Dimming occurs in a few locations next to the flare ribbons, and it is observed in multiple EUV passbands. Rapid dimming starts after the onset of fast reconnection and CME acceleration, and its evolution tracks the CME height and flare reconnection. The spatial distribution of dimming exhibits cores of deep dimming with a rapid growth, and their light curves are approximately linearly scaled with the CME height profile. From the dimming analysis we infer the process of the CME expansion, and estimate properties of the CME.

  11. Identification of DIM-7, a protein required to target the DIM-5 H3 methyltransferase to chromatin

    PubMed Central

    Lewis, Zachary A.; Adhvaryu, Keyur K.; Honda, Shinji; Shiver, Anthony L.; Selker, Eric U.

    2010-01-01

    Functionally distinct chromatin domains are delineated by distinct posttranslational modifications of histones, and in some organisms by differences in DNA methylation. Proper establishment and maintenance of chromatin domains is critical but not well understood. We previously demonstrated that heterochromatin in the filamentous fungus Neurospora crassa is marked by cytosine methylation directed by trimethylated Lysine 9 on histone H3 (H3K9me3). H3K9me3 is the product of the DIM-5 Lysine methyltransferase and is recognized by a protein complex containing heterochromatin protein-1 and the DIM-2 DNA methyltransferase. To identify additional components that control the establishment and function of DNA methylation and heterochromatin, we built a strain harboring two selectable reporter genes that are silenced by DNA methylation and employed this strain to select for mutants that are defective in DNA methylation (dim). We report a previously unidentified gene (dim-7) that is essential for H3K9me3 and DNA methylation. DIM-7 homologs are found only in fungi and are highly divergent. We found that DIM-7 interacts with DIM-5 in vivo and demonstrated that a conserved domain near the N terminus of DIM-7 is required for its stability. In addition, we found that DIM-7 is essential for recruitment of DIM-5 to form heterochromatin. PMID:20404183

  12. Solar dimming/brightening in the Mediterranean

    NASA Astrophysics Data System (ADS)

    Kambezidis, Harry; Demetriou, Dora; Kaskaoutis, Dimitris; Nastos, Panagiotis

    2010-05-01

    Early analyses of solar radiation records have pointed to a widespread decline of surface solar radiation from the 1950s up to the 1980s in various parts of the world. This phenomenon was attributed to increasing air pollution and has been named "global dimming". More recent analyses with data records updated to near present suggested that surface solar radiation shows no sign of decrease anymore since the 1980s or even started to recover at many locations. This recovery has been named "solar brightening". Air pollution control and the economic breakdown of the former communist countries are the major influential factors for this transition. Further the influence of the recovery from the dimming caused by Mt. Pinatubo volcanic eruption in 1991 and internal climate variability with associated cloud variations were suggested to contribute to the brightening in the 1990s. Despite the interest in the solar dimming/brightening phenomenon the Mediterranean area has not attracted the attention of the scientists in this respect so far. Therefore, the present work tries to fill this gap by providing spatio-temporal analysis of the incoming short-wave solar radiation in the whole area of the Mediterranean Sea in the period 1979-2004 taken from satellites. To give better spatial information about the phenomenon the Mediterranean region has been divided into three sub-regions: the West Mediterranean, from Gibraltar to Corsica, the Central Mediterranean, from Corsica to the Ionian Sea, and the East Mediterranean, from the Ionian Sea to the shores of Syria. The analysis shows that the three sub-regions have not undergone the same spatio-temporal pattern of the phenomenon probably due to the different distribution of aerosols in the region.

  13. EUV Dimmings as a Diagnostic of CMEs and Related Phenomena

    NASA Technical Reports Server (NTRS)

    Thompson, Barbara J.; Mays, M. Leila; Webb, David F.; West, Matthew J.

    2012-01-01

    Large-scale coronal EUV dimmings, developing on timescaJes of minutes to hours in association with a flare or filament eruption, are known to exhibit a high correlation with coronal mass ejections. While most observations indicate that the decrease in emission in a dimming is due, at least in part, to a density decrease, a complete understanding requires us to examine at least four mechanisms that have been observed to cause darkened regions in the corona: 1) mass loss, 2) cooling, 3) heating, and 4) absorption/obscuration. Recent advances in automatic detection, observations with improved cadence and resolution, multi-viewpoint imaging, and spectroscopic studies have continued to shed light on dimming formation, evolution, and recovery. However, there are still some outstanding questions, including 1) Why do some CMEs show dimming and some do not? 2) What determines the location of a dimming? 3) What determines the temporal evolution of a dimming? 4) How does the post-eruption dimming connect to the ICME? 5) What is the relationship between dimmings and other CME-associated phenomena? The talk will emphasize the different formation mechanisms of dimmings and their relationship to CMEs and CME-associated phenomena.

  14. Compact plane illumination plugin device to enable light sheet fluorescence imaging of multi-cellular organisms on an inverted wide-field microscope.

    PubMed

    Guan, Zeyi; Lee, Juhyun; Jiang, Hao; Dong, Siyan; Jen, Nelson; Hsiai, Tzung; Ho, Chih-Ming; Fei, Peng

    2016-01-01

    We developed a compact plane illumination plugin (PIP) device which enabled plane illumination and light sheet fluorescence imaging on a conventional inverted microscope. The PIP device allowed the integration of microscope with tunable laser sheet profile, fast image acquisition, and 3-D scanning. The device is both compact, measuring approximately 15 by 5 by 5 cm, and cost-effective, since we employed consumer electronics and an inexpensive device molding method. We demonstrated that PIP provided significant contrast and resolution enhancement to conventional microscopy through imaging different multi-cellular fluorescent structures, including 3-D branched cells in vitro and live zebrafish embryos. Imaging with the integration of PIP greatly reduced out-of-focus contamination and generated sharper contrast in acquired 2-D plane images when compared with the stand-alone inverted microscope. As a result, the dynamic fluid domain of the beating zebrafish heart was clearly segmented and the functional monitoring of the heart was achieved. Furthermore, the enhanced axial resolution established by thin plane illumination of PIP enabled the 3-D reconstruction of the branched cellular structures, which leads to the improvement on the functionality of the wide field microscopy. PMID:26819828

  15. Compact plane illumination plugin device to enable light sheet fluorescence imaging of multi-cellular organisms on an inverted wide-field microscope

    PubMed Central

    Guan, Zeyi; Lee, Juhyun; Jiang, Hao; Dong, Siyan; Jen, Nelson; Hsiai, Tzung; Ho, Chih-Ming; Fei, Peng

    2015-01-01

    We developed a compact plane illumination plugin (PIP) device which enabled plane illumination and light sheet fluorescence imaging on a conventional inverted microscope. The PIP device allowed the integration of microscope with tunable laser sheet profile, fast image acquisition, and 3-D scanning. The device is both compact, measuring approximately 15 by 5 by 5 cm, and cost-effective, since we employed consumer electronics and an inexpensive device molding method. We demonstrated that PIP provided significant contrast and resolution enhancement to conventional microscopy through imaging different multi-cellular fluorescent structures, including 3-D branched cells in vitro and live zebrafish embryos. Imaging with the integration of PIP greatly reduced out-of-focus contamination and generated sharper contrast in acquired 2-D plane images when compared with the stand-alone inverted microscope. As a result, the dynamic fluid domain of the beating zebrafish heart was clearly segmented and the functional monitoring of the heart was achieved. Furthermore, the enhanced axial resolution established by thin plane illumination of PIP enabled the 3-D reconstruction of the branched cellular structures, which leads to the improvement on the functionality of the wide field microscopy. PMID:26819828

  16. STUDY OF THE RECURRING DIMMING REGION DETECTED AT AR 11305 USING THE CORONAL DIMMING TRACKER (CoDiT)

    SciTech Connect

    Krista, Larisza D.; Reinard, Alysha

    2013-01-10

    We present a new approach to coronal dimming detection using the COronal DImming Tracker tool (CODIT), which was found to be successful in locating and tracking multiple dimming regions. This tool, an extension of a previously developed coronal hole tracking software, allows us to study the properties and the spatial evolution of dimming regions at high temporal and spatial cadence from the time of their appearance to their disappearance. We use Solar Dynamics Observatory/Atmospheric Imaging Assembly 193 A wavelength observations and Helioseismic and Magnetic Imager magnetograms to study dimmings. As a demonstration of the detection technique we analyzed six recurrences of a dimming observed near AR 11305 between 2011 September 29 and October 2. The dimming repeatedly appeared and formed in a similar way, first expanding then shrinking and occasionally stabilizing in the same location until the next eruption. The dimming areas were studied in conjunction with the corresponding flare magnitudes and coronal mass ejection (CME) masses. These properties were found to follow a similar trend during the observation period, which is consistent with the idea that the magnitude of the eruption and the CME mass affect the relative sizes of the consecutive dimmings. We also present a hypothesis to explain the evolution of the recurrent single dimming through interchange reconnection. This process would accommodate the relocation of quasi-open magnetic field lines and hence allow the CME flux rope footpoint (the dimming) to expand into quiet-Sun regions. By relating the properties of dimmings, flares, and CMEs we improve our understanding of the magnetic field reconfiguration caused by reconnection.

  17. Mystery of a Dimming White Dwarf

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-12-01

    In the wake of the recent media attention over an enigmatic, dimming star, another intriguing object has been discovered: J1529+2928, a white dwarf that periodically dims. This mystery, however, may have a simple solution with interesting consequences for future surveys of white dwarfs.Unexpected VariabilityJ1529+2928 is an isolated white dwarf that appears to have a mass of slightly more than the Sun. But rather than radiating steadily, J1529+2928 dims once every 38 minutes almost as though it were being eclipsed.The team that discovered these variations, led by Mukremin Kilic (University of Oklahoma), used telescopes at the Apache Point Observatory and the McDonald Observatory to obtain follow-up photometric data of J1529+2928 spread across 66 days. The team also took spectra of the white dwarf with the Gemini North telescope.Kilic and collaborators then began, one by one, to rule out possible causes of this objects variability.Eliminating OptionsThe period of the variability is too long for J1529+2928 to be a pulsating white dwarf with luminosity variation caused by gravity-wave pulsations.The variability cant be due to an eclipse by a stellar or brown-dwarf companion, because there isnt any variation in J1529+2928s radial velocity.Its not due to the orbit of a solid-body planetary object; such a transit would be too short to explain observations.It cant be due to the orbit of a disintegrated planet; this wouldnt explain the light curves observed in different filters plus the light curve doesnt change over the 66-day span.Spotty SurfaceTop and middle two panels: light curves from three different nights observing J1529+2928s periodic dimming. Bottom panel: The Fourier transform shows a peak at 37.7 cycles/day (and another, smaller peak at its first harmonic). [Kilic et al. 2015]So what explanation is left? The authors suggest that J1529+2928s variability is likely caused by a starspot on the white dwarfs surface that rotates into and out of our view. Estimates

  18. A bead-based fluorescence immunosensing technique enabled by the integration of Förster resonance energy transfer and optoelectrokinetic concentration.

    PubMed

    Wang, Jhih-Cheng; Ku, Hu-Yao; Shieh, Dar-Bin; Chuang, Han-Sheng

    2016-01-01

    Bead-based immunosensing has been growing as a promising technology in the point-of-care diagnostics due to great flexibility. For dilute samples, functionalized particles can be used to collect dispersed analytes and act as carriers for particle manipulation. To realize rapid and visual immunosensing, Förster resonance energy transfer (FRET) was used herein to ensure only the diabetic biomarker, lipocalin 1, to be detected. The measurement was made in an aqueous droplet sandwiched between two parallel plate electrodes. With an electric field and a focused laser beam applying on the microchip simultaneously, the immunocomplexes in the droplet were further concentrated to enhance the FRET fluorescent signal. The optoelectrokinetic technique, termed rapid electrokinetic patterning (REP), has been proven to be excellent in dynamic and programmable particle manipulation. Therefore, the detection can be complete within several tens of seconds. The lower detection limit of the REP-enabled bead-based diagnosis reached nearly 5 nM. The combinative use of FRET and the optoelectrokinetic technique for the bead-based immunosensing enables a rapid measure to diagnose early stage diseases and dilute analytes. PMID:26865906

  19. What Do EUV Dimmings Tell Us About CME Topology?

    NASA Astrophysics Data System (ADS)

    Thompson, B. J.; DeRosa, M. L.; Fisher, R. R.; Krista, L. D.; Kwon, R. Y.; Mason, J. P.; Mays, M. L.; Nitta, N.; Savani, N.; West, M. J.

    2014-12-01

    Large-scale coronal EUV dimmings, developing on timescales of minutes to hours in association with a flare or filament eruption, are known to exhibit a high correlation with coronal mass ejections. However, it is not clear why some CMEs have dimmings and some do not, nor is it clear how these dimmings relate to CME topology. The inner coronal coverage of SDO AIA and STEREO EUVI, combined with the extended field of view of PROBA2's SWAP imager, allow us the opportunity to map the topology of a dimming region in three dimensions into an erupting CME. Although the location and extent of a dimming region appears to be the best indicator of the inner "footprint" of a CME, the correlation is far from perfect. However, dimmings can provide vital clues about the development and 3D kinematics of a CME. This is particularly important as we are entering an extended period of time where STEREO coronagraph images will not always be available, and therefore the 3D properties of a CME will be difficult to deduce. Therefore, understanding the inner coronal manifestations of a CME can provide clues to its structure and dynamics, even without multi-viewpoint coronagraph observations. We present the results of this combined analysis effort, along with a discussion of how dimmings can be used in forecasting CME directions.

  20. What Do EUV Dimmings Tell Us About CME Topology

    NASA Astrophysics Data System (ADS)

    Thompson, Barbara J.; DeRosa, Marc L.; Fisher, Richard R.; Krista, Larisza D.; Kwon, Ryun Young; Mason, James P.; Mays, Mona L.; Nitta, Nariaki V.; Webb, David F.; West, Matthew J.

    2015-04-01

    Large-scale coronal EUV dimmings develop on timescales of hours in association with a flare or filament eruption, and are known to be well correlated with coronal mass ejections (CMEs). However, it is not clear why some CMEs have dimmings and some do not, nor is it clear how these dimmings relate to CME topology. The inner coronal coverage of SDO AIA and STEREO EUVI, combined with the extended field of view of PROBA2's SWAP imager, allow us the opportunity to map the topology of a dimming region in three dimensions into an erupting CME. Although the location and extent of a dimming region appears to be the best indicator of the inner "footprint" of a CME, the correlation is far from perfect. However, dimmings can provide vital clues about the development and 3D kinematics of CMEs. This is particularly important as we are currently in an extended period where the STEREO coronagraph images are not always available and are increasingly "mirroring" LASCO images, and therefore the 3D properties of a CME will be difficult to deduce. Thus, understanding the inner coronal manifestations of a CME can provide clues to its structure and dynamics, even without multi-viewpoint coronagraph observations. We present the results of this combined analysis effort, along with a discussion of how dimmings can be used to forecast CME trajectories.

  1. EUV Coronal Dimming and its Relationship to Coronal Mass Ejections

    NASA Astrophysics Data System (ADS)

    Mason, James

    2016-05-01

    As a coronal mass ejection (CME) departs from the inner solar atmosphere, it leaves behind a void. This region of depleted plasma results in a corresponding decrease in coronal emissions that can be observed by instruments tuned to measure the extreme ultraviolet (EUV) part of the electromagnetic spectrum. These coronal dimmings can be observed with EUV imagers and EUV spectral irradiance instruments. Onboard the Solar Dynamics Observatory (SDO), the EUV Variability Experiment (EVE) and Atmospheric Imaging Assembly (AIA) provide complementary observations; together they can be used to obtain high spatial and spectral resolution. AIA provides information about the location, extent, and spatial evolution of the dimming while EVE data are important to understand plasma temperature evolution. Concurrent processes with similar timescales to mass-loss dimming also impact the observations, which makes a deconvolution method necessary for the irradiance time series in order to have a “clean” mass-loss dimming light curve that can be parameterized and compared with CME kinematics. This presentation will first provide background on these various physical processes and the deconvolution method developed. Two case studies will then be presented, followed by a semi-statistical study (~30 events) to establish a correlation between dimming and CME parameters. In particular, the slope of the deconvolved irradiance dimming light curve is representative of the CME speed, and the irradiance dimming depth can serve as a proxy for CME mass. Finally, plans and early results from a more complete statistical study of all dimmings in the SDO era, based on an automated detection routine using EVE data, will be described and compared with independently derived dimmings automatically detected with AIA data.

  2. Detection of dim targets in multiple environments

    NASA Astrophysics Data System (ADS)

    Mirsky, Grace M.; Woods, Matthew; Grasso, Robert J.

    2013-10-01

    The proliferation of a wide variety of weapons including Anti-Aircraft Artillery (AAA), rockets, and small arms presents a substantial threat to both military and civilian aircraft. To address this ever-present threat, Northrop Grumman has assessed unguided threat phenomenology to understand the underlying physical principles for detection. These principles, based upon threat transit through the atmosphere, exploit a simple phenomenon universal to all objects moving through an atmosphere comprised of gaseous media to detect and track the threat in the presence of background and clutter. Threat detection has rapidly become a crucial component of aircraft survivability systems that provide situational awareness to the crew. It is particularly important to platforms which may spend a majority of their time at low altitudes and within the effective range of a large variety of weapons. Detection of these threats presents a unique challenge as this class of threat typically has a dim signature coupled with a short duration. Correct identification of each of the threat components (muzzle flash and projectile) is important to determine trajectory and intent while minimizing false alarms and maintaining a high detection probability in all environments.

  3. Photic niche invasions: phylogenetic history of the dim-light foraging augochlorine bees (Halictidae).

    PubMed

    Tierney, Simon M; Sanjur, Oris; Grajales, Grethel G; Santos, Leandro M; Bermingham, Eldredge; Wcislo, William T

    2012-02-22

    Most bees rely on flowering plants and hence are diurnal foragers. From this ancestral state, dim-light foraging in bees requires significant adaptations to a new photic environment. We used DNA sequences to evaluate the phylogenetic history of the most diverse clade of Apoidea that is adapted to dim-light environments (Augochlorini: Megalopta, Megaloptidia and Megommation). The most speciose lineage, Megalopta, is distal to the remaining dim-light genera, and its closest diurnal relative (Xenochlora) is recovered as a lineage that has secondarily reverted to diurnal foraging. Tests for adaptive protein evolution indicate that long-wavelength opsin shows strong evidence of stabilizing selection, with no more than five codons (2%) under positive selection, depending on analytical procedure. In the branch leading to Megalopta, the amino acid of the single positively selected codon is conserved among ancestral Halictidae examined, and is homologous to codons known to influence molecular structure at the chromophore-binding pocket. Theoretically, such mutations can shift photopigment λ(max) sensitivity and enable visual transduction in alternate photic environments. Results are discussed in light of the available evidence on photopigment structure, morphological specialization and biogeographic distributions over geological time.

  4. Dynamic programming algorithm for detecting dim infrared moving targets

    NASA Astrophysics Data System (ADS)

    He, Lisha; Mao, Liangjing; Xie, Lijun

    2009-10-01

    Infrared (IR) target detection is a key part of airborne infrared weapon system, especially the detection of poor dim moving IR target embedded in complex context. This paper presents an improved Dynamic Programming (DP) algorithm in allusion to low Signal to Noise Ratio (SNR) infrared dim moving targets under cluttered context. The algorithm brings the dim target to prominence by accumulating the energy of pixels in the image sequence, after suppressing the background noise with a mathematical morphology preprocessor. As considering the continuity and stabilization of target's energy and forward direction, this algorithm has well solved the energy scattering problem that exists in the original DP algorithm. An effective energy segmentation threshold is given by a Contrast-Limited Adaptive Histogram Equalization (CLAHE) filter with a regional peak extraction algorithm. Simulation results show that the improved DP tracking algorithm performs well in detecting poor dim targets.

  5. Neural Summation in the Hawkmoth Visual System Extends the Limits of Vision in Dim Light.

    PubMed

    Stöckl, Anna Lisa; O'Carroll, David Charles; Warrant, Eric James

    2016-03-21

    Most of the world's animals are active in dim light and depend on good vision for the tasks of daily life. Many have evolved visual adaptations that permit a performance superior to that of manmade imaging devices [1]. In insects, a major model visual system, nocturnal species show impressive visual abilities ranging from flight control [2, 3], to color discrimination [4, 5], to navigation using visual landmarks [6-8] or dim celestial compass cues [9, 10]. In addition to optical adaptations that improve their sensitivity in dim light [11], neural summation of light in space and time-which enhances the coarser and slower features of the scene at the expense of noisier finer and faster features-has been suggested to improve sensitivity in theoretical [12-14], anatomical [15-17], and behavioral [18-20] studies. How these summation strategies function neurally is, however, presently unknown. Here, we quantified spatial and temporal summation in the motion vision pathway of a nocturnal hawkmoth. We show that spatial and temporal summation combine supralinearly to substantially increase contrast sensitivity and visual information rate over four decades of light intensity, enabling hawkmoths to see at light levels 100 times dimmer than without summation. Our results reveal how visual motion is calculated neurally in dim light and how spatial and temporal summation improve sensitivity while simultaneously maximizing spatial and temporal resolution, thus extending models of insect motion vision derived predominantly from diurnal flies. Moreover, the summation strategies we have revealed may benefit manmade vision systems optimized for variable light levels [21]. PMID:26948877

  6. Integrated Fluorescence

    NASA Technical Reports Server (NTRS)

    Tuma, Margaret (Inventor); Gruhlke, Russell W. (Inventor)

    1998-01-01

    A detection method is integrated with a filtering method and an enhancement method to create a fluorescence sensor that can be miniaturized. The fluorescence sensor comprises a thin film geometry including a waveguide layer, a metal film layer and sensor layer. The thin film geometry of the fluorescence sensor allows the detection of fluorescent radiation over a narrow wavelength interval. This enables wavelength discrimination and eliminates the detection of unwanted light from unknown or spurious sources.

  7. Research on the detection technology to dim and small target

    NASA Astrophysics Data System (ADS)

    Liu, Yu; Chen, Feng; Huang, Jianming; Wei, Xiangquan

    2015-03-01

    With the development of Space Technology, the demand to Space Surveillance System is more urgent than before. The paper studies the dim and small target of long range. Firstly, it describes the research status of dim and small target abroad and the two detection principle of DBT and TBD. Secondly, it focuses on the higher-order correlation method, dynamic programming method and projection transformation method of TBD. Finally, it studies the image sequence simulation of different signal to noise ratio (SNR) with the real-time data from the aircraft in orbit. The image sequence is used to experimental verification. The test results show the dim and small target detection capability and applicable occasion of different methods. At the same time, it provides a new idea to the development of long-distance optical detector.

  8. Dim light at night increases body mass of female mice.

    PubMed

    Aubrecht, Taryn G; Jenkins, Richelle; Nelson, Randy J

    2015-05-01

    During the past century, the prevalence of light at night has increased in parallel with obesity rates. Dim light at night (dLAN) increases body mass in male mice. However, the effects of light at night on female body mass remain unspecified. Thus, female mice were exposed to a standard light/dark (LD; 16 h light at ∼150 lux/8 h dark at ∼0 lux) cycle or to light/dim light at night (dLAN; 16 h light at ∼150 lux/8 h dim light at ∼5 lux) cycles for six weeks. Females exposed to dLAN increased the rate of change in body mass compared to LD mice despite reduced total food intake during weeks five and six, suggesting that dLAN disrupted circadian rhythms resulting in deranged metabolism.

  9. Scanning Single-Molecule Fluorescence Correlation Spectroscopy Enables Kinetics Study of DNA Hairpin Folding with a Time Window from Microseconds to Seconds.

    PubMed

    Bi, Huimin; Yin, Yandong; Pan, Bailong; Li, Geng; Zhao, Xin Sheng

    2016-05-19

    Single-molecule fluorescence measurements have been widely used to explore kinetics and dynamics of biological systems. Among them, single-molecule imaging (SMI) is good at tracking processes slower than tens of milliseconds, whereas fluorescence correlation spectroscopy (FCS) is good at probing processes faster than submilliseconds. However, there is still shortage of simple yet effective single-molecule fluorescence method to cover the time-scale between submilliseconds and tens of milliseconds. To effectively bridge this millisecond gap, we developed a single-molecule fluorescence correlation spectroscopy (smFCS) method that works on surface-immobilized single molecules through surface scanning. We validated it by monitoring the classical DNA hairpin folding process. With a wide time window from microseconds to seconds, the experimental data are well fitted to the two-state folding model. All relevant molecular parameters, including the relative fluorescence brightness, equilibrium constant, and reaction rate constants, were uniquely determined.

  10. Explicit examples of DIM constraints for network matrix models

    NASA Astrophysics Data System (ADS)

    Awata, Hidetoshi; Kanno, Hiroaki; Matsumoto, Takuya; Mironov, Andrei; Morozov, Alexei; Morozov, Andrey; Ohkubo, Yusuke; Zenkevich, Yegor

    2016-07-01

    Dotsenko-Fateev and Chern-Simons matrix models, which describe Nekrasov functions for SYM theories in different dimensions, are all incorporated into network matrix models with the hidden Ding-Iohara-Miki (DIM) symmetry. This lifting is especially simple for what we call balanced networks. Then, the Ward identities (known under the names of Virasoro/ {W} -constraints or loop equations or regularity condition for qq-characters) are also promoted to the DIM level, where they all become corollaries of a single identity.

  11. An effective algorithm for radar dim moving target detection

    NASA Astrophysics Data System (ADS)

    Luo, Qian; Wang, Yanfei

    2009-10-01

    The detection and tracking of dim moving targets in very low signal-to-noise ratio (SNR) environment has been a difficult problem in radar signal processing. For low SNR moving targets detection, a new improved dynamic programming algorithm based on track-before-detection method is presented. This new algorithm integrates energy along target moving tracks according to target moving parameter information. This process substitutes the exhaustive search by a feasible algorithm. The simulation confirms that this algorithm, with high computational efficiency, is feasible, and can effectively estimate trajectories of dim closing moving targets. The process has also been shown to give an increase in detection.

  12. Experiment S030: Dim sky photography/orthicon

    NASA Technical Reports Server (NTRS)

    Dunkelman, L.; Mercer, R. D.; Ney, E. P.; Hemenway, C. L.

    1971-01-01

    During Gemini missions, the image orthicon system was used to obtain photographic data on faint and diffuse astronomical phenomena. Results show that the photographs may be used to determine the airglow geometry. Although it was sensitive, the original photographic system was unsuitable for use in the study of dim and diffuse astronomical light sources.

  13. BIOCONAID System (Bionic Control of Acceleration Induced Dimming). Final Report.

    ERIC Educational Resources Information Center

    Rogers, Dana B.; And Others

    The system described represents a new technique for enhancing the fidelity of flight simulators during high acceleration maneuvers. This technique forces the simulator pilot into active participation and energy expenditure similar to the aircraft pilot undergoing actual accelerations. The Bionic Control of Acceleration Induced Dimming (BIOCONAID)…

  14. Projection effects in coronal dimmings and associated EUV wave event

    NASA Astrophysics Data System (ADS)

    Dissauer, Karin; Temmer, Manuela; Veronig, Astrid; Vanninathan, Kamalam; Magdalenic, Jasmina

    2016-04-01

    We investigate the high-speed (v > 1000 km s-1) extreme-ultraviolet (EUV) wave associated with an X1.2 flare and coronal mass ejection (CME) from NOAA active region 11283. This EUV wave features peculiar on-disk signatures, in particular we observe an intermittent "disappearance" of the front for 120 s in SDO/AIA 171, 193, 211 Å data, whereas the 335 Å filter, sensitive to hotter plasmas (T˜ 2.5 MK), shows a continuous evolution of the wave front. We exploit the multi-point quadrature position of SDO and STEREO-A, to make a thorough analysis of the EUV wave evolution, with respect to its kinematics and amplitude evolution. We identify on-disk coronal dimming regions in SDO/AIA, reminiscent of core dimmings, that have no corresponding on-disk dimming signatures in STEREO-A/EUVI. Reconstructing the SDO line-of-sight (LOS) direction in STEREO-A clearly shows that the observed SDO on-disk dimming areas are not the footprints of the erupting fluxrope but result from decreased emission from the expanding CME body integrated along the LOS. In this context, we conclude that the intermittent disappearance of the EUV wave in the AIA 171, 193, 211 Å filters, which are channels sensitive to plasma with temperatures below ˜ 2 MK is also caused by such LOS integration effects. These observations clearly demonstrate that single-view image data provide us with limited insight to correctly interpret coronal features.

  15. Image-classification-based global dimming algorithm for LED backlights in LCDs

    NASA Astrophysics Data System (ADS)

    Qibin, Feng; Huijie, He; Dong, Han; Lei, Zhang; Guoqiang, Lv

    2015-07-01

    Backlight dimming can help LCDs reduce power consumption and improve CR. With fixed parameters, dimming algorithm cannot achieve satisfied effects for all kinds of images. The paper introduces an image-classification-based global dimming algorithm. The proposed classification method especially for backlight dimming is based on luminance and CR of input images. The parameters for backlight dimming level and pixel compensation are adaptive with image classifications. The simulation results show that the classification based dimming algorithm presents 86.13% power reduction improvement compared with dimming without classification, with almost same display quality. The prototype is developed. There are no perceived distortions when playing videos. The practical average power reduction of the prototype TV is 18.72%, compared with common TV without dimming.

  16. A novel rhodamine-riboflavin conjugate probe exhibits distinct fluorescence resonance energy transfer that enables riboflavin trafficking and subcellular localization studies.

    PubMed

    Phelps, Mitch A; Foraker, Amy B; Gao, Wenqing; Dalton, James T; Swaan, Peter W

    2004-01-01

    Riboflavin (vitamin B2, RF) is taken up in eukaryotic cells via specialized transport mechanisms. Although RF has fluorescence properties, direct microscopic visualization of RF uptake and trafficking has been complicated by cellular autofluorescence. We describe the synthesis, cellular uptake characteristics, and spectroscopic properties of a novel rhodamine-riboflavin conjugate (RD-RF), including absorption and emission spectra, two-photon excitation spectra, and fluorescence pH dependence. The conjugate has a molar extinction coefficient of 23 670 M(-1) cm(-1) at 545 nm (excitation wavelength) with a fluorescence quantum yield of 0.94. This compound exhibits intramolecular fluorescence resonance energy transfer (FRET). Selective quenching of the FRET signal is observed when RD-RF is bound with high affinity by the chicken riboflavin carrier protein. In addition to the typical rhodamine excitation and emission, FRET provides a secondary signal for conjugate localization and an in situ mechanism for observing riboflavin binding. Solution and in vitro stability determinations indicate that the linkage between riboflavin and rhodamine is stable for the duration of typical pulse--chase and cellular trafficking experiments. The distinct spectroscopic properties of RD-RF together with a comparable affinity for RF-binding proteins render it an excellent tool for the study of RF transport and trafficking in living cells. PMID:15981585

  17. Detection of bright and dim colours by honeybees.

    PubMed

    Hempel De Ibarra, N; Vorobyev, M; Brandt, R; Giurfa, M

    2000-11-01

    Honeybees, Apis mellifera, were trained to detect coloured disks with either a strong or a weak intensity difference against the background. Green, blue, ultraviolet-reflecting white and grey papers were reciprocally combined as targets or backgrounds, providing strong chromatic and/or achromatic cues. The behavioural performance of the honeybees was always symmetrical for both reciprocal target/background combinations of a colour pair, thus showing that target detection is independent of whether the colour is presented as a background or as a target in combination with the other colour. Bright targets against dim backgrounds and vice versa were detected more reliably than dim target/background combinations. This result favours the general assumption that the detectability of a coloured stimulus increases with increasing intensity.

  18. A novel local dimming algorithm for RGB-LED backlight

    NASA Astrophysics Data System (ADS)

    Huang, Wei; Jin, Zhong-Liang; Zhong, Zheng-Gen; Liu, Yu; Liu, Duan; Ming, Hai; Chou, Qin-Ying; Li, Feng

    2009-11-01

    A large size RGB LED backlight unit and its local dimming algorithm are presented in this paper. The LED backlight unit and the LCD panel are controlled synchronously to enhance image contrast and improve power efficacy. Based on the image content, the backlight intensity is locally dimmed, and pixel values are compensated according to the backlight brightness distribution. In addition, a linear function algorithm typical for a backlight system is applied to remove the grid artifacts between LED blocks. Our newly developed 32" RGB LED backlight LCD-TV prototype shows that a static display contrast of over 20000:1 can be achieved. Compared with CCFL backlight LCD-TV, an average of about 30% of the power can be saved depending on the image content.

  19. Dimming-discrete-multi-tone (DMT) for simultaneous color control and high speed visible light communication.

    PubMed

    Sung, Jiun-Yu; Chow, Chi-Wai; Yeh, Chien-Hung

    2014-04-01

    Visible light communication (VLC) using LEDs has attracted significant attention recently for the future secure, license-free and electromagnetic-interference (EMI)-free optical wireless communication. Dimming technique in LED lamp is advantageous for energy efficiency. Color control can be performed in the red-green-blue (RGB) LEDs by using dimming technique. It is highly desirable to employ dimming technique to provide simultaneous color and dimming control and high speed VLC. Here, we proposed and demonstrated a LED dimming control using dimming-discrete-multi-tone (DMT) modulation. High speed DMT-based VLC with simultaneous color and dimming control is demonstrated for the first time to the best of our knowledge. Demonstration and analyses for several modulation conditions and transmission distances are performed, for instance, demonstrating the data rate of 103.5 Mb/s (using RGB LED) with fast Fourier transform (FFT) size of 512.

  20. FAST EXTREME-ULTRAVIOLET DIMMING ASSOCIATED WITH A CORONAL JET SEEN IN MULTI-WAVELENGTH AND STEREOSCOPIC OBSERVATIONS

    SciTech Connect

    Lee, K.-S.; Moon, Y.-J.; Lee, Jin-Yi; Innes, D. E.; Shibata, K.; Park, Y.-D.

    2013-03-20

    We have investigated a coronal jet observed near the limb on 2010 June 27 by the Hinode/X-Ray Telescope (XRT), EUV Imaging Spectrograph (EIS), and Solar Optical Telescope (SOT), and by the Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA), and on the disk by STEREO-A/EUVI. From EUV (AIA and EIS) and soft X-ray (XRT) images we have identified both cool and hot jets. There was a small loop eruption seen in Ca II images of the SOT before the jet eruption. We found that the hot jet preceded its associated cool jet by about 2 minutes. The cool jet showed helical-like structures during the rising period which was supported by the spectroscopic analysis of the jet's emission. The STEREO observation, which enabled us to observe the jet projected against the disk, showed dimming at 195 A along a large loop connected to the jet. We measured a propagation speed of {approx}800 km s{sup -1} for the dimming front. This is comparable to the Alfven speed in the loop computed from a magnetic field extrapolation of the photospheric field measured five days earlier by the SDO/Helioseismic and Magnetic Imager, and the loop densities obtained from EIS Fe XIV {lambda}264.79/274.20 line ratios. We interpret the dimming as indicating the presence of Alfvenic waves initiated by reconnection in the upper chromosphere.

  1. Adaptive-optics SLO imaging combined with widefield OCT and SLO enables precise 3D localization of fluorescent cells in the mouse retina.

    PubMed

    Zawadzki, Robert J; Zhang, Pengfei; Zam, Azhar; Miller, Eric B; Goswami, Mayank; Wang, Xinlei; Jonnal, Ravi S; Lee, Sang-Hyuck; Kim, Dae Yu; Flannery, John G; Werner, John S; Burns, Marie E; Pugh, Edward N

    2015-06-01

    Adaptive optics scanning laser ophthalmoscopy (AO-SLO) has recently been used to achieve exquisite subcellular resolution imaging of the mouse retina. Wavefront sensing-based AO typically restricts the field of view to a few degrees of visual angle. As a consequence the relationship between AO-SLO data and larger scale retinal structures and cellular patterns can be difficult to assess. The retinal vasculature affords a large-scale 3D map on which cells and structures can be located during in vivo imaging. Phase-variance OCT (pv-OCT) can efficiently image the vasculature with near-infrared light in a label-free manner, allowing 3D vascular reconstruction with high precision. We combined widefield pv-OCT and SLO imaging with AO-SLO reflection and fluorescence imaging to localize two types of fluorescent cells within the retinal layers: GFP-expressing microglia, the resident macrophages of the retina, and GFP-expressing cone photoreceptor cells. We describe in detail a reflective afocal AO-SLO retinal imaging system designed for high resolution retinal imaging in mice. The optical performance of this instrument is compared to other state-of-the-art AO-based mouse retinal imaging systems. The spatial and temporal resolution of the new AO instrumentation was characterized with angiography of retinal capillaries, including blood-flow velocity analysis. Depth-resolved AO-SLO fluorescent images of microglia and cone photoreceptors are visualized in parallel with 469 nm and 663 nm reflectance images of the microvasculature and other structures. Additional applications of the new instrumentation are discussed.

  2. Adaptive-optics SLO imaging combined with widefield OCT and SLO enables precise 3D localization of fluorescent cells in the mouse retina

    PubMed Central

    Zawadzki, Robert J.; Zhang, Pengfei; Zam, Azhar; Miller, Eric B.; Goswami, Mayank; Wang, Xinlei; Jonnal, Ravi S.; Lee, Sang-Hyuck; Kim, Dae Yu; Flannery, John G.; Werner, John S.; Burns, Marie E.; Pugh, Edward N.

    2015-01-01

    Adaptive optics scanning laser ophthalmoscopy (AO-SLO) has recently been used to achieve exquisite subcellular resolution imaging of the mouse retina. Wavefront sensing-based AO typically restricts the field of view to a few degrees of visual angle. As a consequence the relationship between AO-SLO data and larger scale retinal structures and cellular patterns can be difficult to assess. The retinal vasculature affords a large-scale 3D map on which cells and structures can be located during in vivo imaging. Phase-variance OCT (pv-OCT) can efficiently image the vasculature with near-infrared light in a label-free manner, allowing 3D vascular reconstruction with high precision. We combined widefield pv-OCT and SLO imaging with AO-SLO reflection and fluorescence imaging to localize two types of fluorescent cells within the retinal layers: GFP-expressing microglia, the resident macrophages of the retina, and GFP-expressing cone photoreceptor cells. We describe in detail a reflective afocal AO-SLO retinal imaging system designed for high resolution retinal imaging in mice. The optical performance of this instrument is compared to other state-of-the-art AO-based mouse retinal imaging systems. The spatial and temporal resolution of the new AO instrumentation was characterized with angiography of retinal capillaries, including blood-flow velocity analysis. Depth-resolved AO-SLO fluorescent images of microglia and cone photoreceptors are visualized in parallel with 469 nm and 663 nm reflectance images of the microvasculature and other structures. Additional applications of the new instrumentation are discussed. PMID:26114038

  3. Thermal oxidation process accelerates degradation of the olive oil mixed with sunflower oil and enables its discrimination using synchronous fluorescence spectroscopy and chemometric analysis.

    PubMed

    Mabood, Fazal; Boqué, Ricard; Folcarelli, Rita; Busto, Olga; Al-Harrasi, Ahmed; Hussain, Javid

    2015-05-15

    We have investigated the effect of thermal treatment on the discrimination of pure extra virgin olive oil (EVOO) samples from EVOO samples adulterated with sunflower oil. Two groups of samples were used. One group was analyzed at room temperature (25°C) and the other group was thermally treated in a thermostatic water bath at 75°C for 8h, in contact with air and with light exposure, to favor oxidation. All samples were then measured with synchronous fluorescence spectroscopy. Fluorescence spectra were acquired by varying the excitation wavelength in the region from 250 to 720nm. In order to optimize the differences between excitation and emission wavelengths, four constant differential wavelengths, i.e., 20nm, 40nm, 60nm and 80nm, were tried. Partial least-squares discriminant analysis (PLS-DA) was used to discriminate between pure and adulterated oils. It was found that the 20nm difference was the optimal, at which the discrimination models showed the best results. The best PLS-DA models were those built with the difference spectra (75-25°C), which were able to discriminate pure from adulterated oils at a 2% level of adulteration. Furthermore, PLS regression models were built to quantify the level of adulteration. Again, the best model was the one built with the difference spectra, with a prediction error of 1.75% of adulteration.

  4. Thermal oxidation process accelerates degradation of the olive oil mixed with sunflower oil and enables its discrimination using synchronous fluorescence spectroscopy and chemometric analysis

    NASA Astrophysics Data System (ADS)

    Mabood, Fazal; Boqué, Ricard; Folcarelli, Rita; Busto, Olga; Al-Harrasi, Ahmed; Hussain, Javid

    2015-05-01

    We have investigated the effect of thermal treatment on the discrimination of pure extra virgin olive oil (EVOO) samples from EVOO samples adulterated with sunflower oil. Two groups of samples were used. One group was analyzed at room temperature (25 °C) and the other group was thermally treated in a thermostatic water bath at 75 °C for 8 h, in contact with air and with light exposure, to favor oxidation. All samples were then measured with synchronous fluorescence spectroscopy. Fluorescence spectra were acquired by varying the excitation wavelength in the region from 250 to 720 nm. In order to optimize the differences between excitation and emission wavelengths, four constant differential wavelengths, i.e., 20 nm, 40 nm, 60 nm and 80 nm, were tried. Partial least-squares discriminant analysis (PLS-DA) was used to discriminate between pure and adulterated oils. It was found that the 20 nm difference was the optimal, at which the discrimination models showed the best results. The best PLS-DA models were those built with the difference spectra (75-25 °C), which were able to discriminate pure from adulterated oils at a 2% level of adulteration. Furthermore, PLS regression models were built to quantify the level of adulteration. Again, the best model was the one built with the difference spectra, with a prediction error of 1.75% of adulteration.

  5. Two-photon excitation in chip electrophoresis enabling label-free fluorescence detection in non-UV transparent full-body polymer chips.

    PubMed

    Geissler, David; Belder, Detlev

    2015-12-01

    One of the most commonly employed detection methods in microfluidic research is fluorescence detection, due to its ease of integration and excellent sensitivity. Many analytes though do not show luminescence when excited in the visible light spectrum, require suitable dyes. Deep-ultraviolet (UV) excitation (<300 nm) allows label-free detection of a broader range of analytes but also mandates the use of expensive fused silica glass, which is transparent to UV light. Herein, we report the first application of label-free deep UV fluorescence detection in non-UV transparent full-body polymer microfluidic devices. This was achieved by means of two-photon excitation in the visible range (λex = 532 nm). Issues associated with the low optical transmittance of plastics in the UV range were successfully circumvented in this way. The technique was investigated by application to microchip electrophoresis of small aromatic compounds. Various polymers, such as poly(methyl methacrylate), cyclic olefin polymer, and copolymer as well as poly(dimethylsiloxane) were investigated and compared with respect to achievable LOD and ruggedness against photodamage. To demonstrate the applicability of the technique, the method was also applied to the determination of serotonin and tryptamine in fruit samples.

  6. Zn(2+) binding-enabled excited state intramolecular proton transfer: a step toward new near-infrared fluorescent probes for imaging applications.

    PubMed

    Xu, Yongqian; Liu, Qin; Dou, Bairui; Wright, Brian; Wang, Jingyun; Pang, Yi

    2012-07-01

    In order to facilitate the in vivo study of zinc-related biology, it is essential to develop a zinc-selective sensor that exhibits both near-infrared (NIR) emission and larger Stokes shift. A fluorescent sensor, Zinhbo-5, has been constructed by using bis(benzoxazole) ligand with 2, 2'-dipicolylamine (DPA) as metal ion receptor. In aqueous solution, Zinhbo-5 exhibits high sensitivity (K(d) = 2.58 nM(2) ) and selectivity for Zn(2+) cation, revealing about 14-fold fluorescence enhancement upon zinc binding to give green emission. Remarkably, Zn(2+) binding to Zinhbo-5 switches on the excited state intramolecular proton transfer (ESIPT), producing the desirable near-infrared region (over 710 nm) with large Stokes shift (ca. 240 nm). The new probe is demonstrated to be useful for in vivo imaging of the intracellular Zn(2+) ion. The Zinhbo-5 is also useful for detecting zinc ion distribution during the development of living zebrafish embryos.

  7. Two-photon excitation in chip electrophoresis enabling label-free fluorescence detection in non-UV transparent full-body polymer chips.

    PubMed

    Geissler, David; Belder, Detlev

    2015-12-01

    One of the most commonly employed detection methods in microfluidic research is fluorescence detection, due to its ease of integration and excellent sensitivity. Many analytes though do not show luminescence when excited in the visible light spectrum, require suitable dyes. Deep-ultraviolet (UV) excitation (<300 nm) allows label-free detection of a broader range of analytes but also mandates the use of expensive fused silica glass, which is transparent to UV light. Herein, we report the first application of label-free deep UV fluorescence detection in non-UV transparent full-body polymer microfluidic devices. This was achieved by means of two-photon excitation in the visible range (λex = 532 nm). Issues associated with the low optical transmittance of plastics in the UV range were successfully circumvented in this way. The technique was investigated by application to microchip electrophoresis of small aromatic compounds. Various polymers, such as poly(methyl methacrylate), cyclic olefin polymer, and copolymer as well as poly(dimethylsiloxane) were investigated and compared with respect to achievable LOD and ruggedness against photodamage. To demonstrate the applicability of the technique, the method was also applied to the determination of serotonin and tryptamine in fruit samples. PMID:26333008

  8. Tampa Bay Study Data and Information Management System (DIMS)

    NASA Astrophysics Data System (ADS)

    Edgar, N. T.; Johnston, J. B.; Yates, K.; Smith, K. E.

    2005-05-01

    Providing easy access to data and information is an essential component of both science and management. The Tampa Bay Data and Information Management System (DIMS) catalogs and publicizes data and products which are generated through the Tampa Bay Integrated Science Study. The publicly accessible interface consists of a Web site (http://gulfsci.usgs.gov), a digital library, and an interactive map server (IMS). The Tampa Bay Study Web site contains information from scientists involved in the study, and is also the portal site for the digital library and IMS. Study information is highlighted on the Web site according to the estuarine component: geology and geomorphology, water and sediment quality, ecosystem structure and function, and hydrodynamics. The Tampa Bay Digital Library is a web-based clearinghouse for digital products on Tampa Bay, including documents, maps, spatial and tabular data sets, presentations, etc. New developments to the digital library include new search features, 150 new products over the past year, and partnerships to expand the offering of science products. The IMS is a Web-based geographic information system (GIS) used to store, analyze and display data pertaining to Tampa Bay. Upgrades to the IMS have improved performance and speed, as well as increased the number of data sets available for mapping. The Tampa Bay DIMS is a dynamic entity and will continue to evolve with the study. Beginning in 2005, the Tampa Bay Integrated Coastal Model will have a more prominent presence within the DIMS. The Web site will feature model projects and plans; the digital library will host model products and data sets; the IMS will display spatial model data sets and analyses. These tools will be used to increase communication of USGS efforts in Tampa Bay to the public, local managers, and scientists.

  9. THE TEMPERATURE-DEPENDENT NATURE OF CORONAL DIMMINGS

    SciTech Connect

    Robbrecht, Eva; Wang Yiming E-mail: Yi.Wang@nrl.navy.mi

    2010-09-01

    The opening-up of the magnetic field during solar eruptive events is often accompanied by a dimming of the local coronal emission. From observations of filament eruptions recorded with the Extreme-Ultraviolet Imager on STEREO during 2008-2009, it is evident that these dimmings are much more pronounced in 19.5 nm than in the lower-temperature line 17.1 nm, as viewed either on the disk or above the limb. We conclude that most of the cooler coronal plasma is not ejected but remains gravitationally bound when the loops open up. This result is consistent with Doppler measurements by Imada and coworkers, who found that the upflow speeds in a transient coronal hole increased dramatically above a temperature of 1 MK; it is also consistent with the quasistatic behavior of polar plumes, as compared with the hotter interplume regions that are the main source of the fast solar wind. When the open flux reconnects and closes down again, the trapped plasma is initially heated to such high temperatures that it is no longer visible at Fe IX 17.1 nm. Correspondingly, 17.1 nm images show a dark ribbon or 'heat wave' propagating away from the polarity inversion line and coinciding with the brightened Fe XV 28.4 nm and Fe XII 19.5 nm post-eruptive loops and their footpoint areas. Such dark ribbons provide a clear example of dimmings that are not caused by a density depletion. The propagation of the 'heat wave' is driven by the closing-down, not the opening-up, of the flux and can be observed both off-limb and on-disk.

  10. Projection Effects in Coronal Dimmings and Associated EUV Wave Event

    NASA Astrophysics Data System (ADS)

    Dissauer, K.; Temmer, M.; Veronig, A. M.; Vanninathan, K.; Magdalenić, J.

    2016-10-01

    We investigate the high-speed (v > 1000 km s‑1) extreme-ultraviolet (EUV) wave associated with an X1.2 flare and coronal mass ejection (CME) from NOAA active region 11283 on 2011 September 6 (SOL2011-09-06T22:12). This EUV wave features peculiar on-disk signatures in particular, we observe an intermittent “disappearance” of the front for 120 s in Solar Dynamics Observatory (SDO)/AIA 171, 193, 211 Å data, whereas the 335 Å filter, sensitive to hotter plasmas (T ∼ 2.5 MK), shows a continuous evolution of the wave front. The eruption was also accompanied by localized coronal dimming regions. We exploit the multi-point quadrature position of SDO and STEREO-A, to make a thorough analysis of the EUV wave evolution, with respect to its kinematics and amplitude evolution and reconstruct the SDO line-of-sight (LOS) direction of the identified coronal dimming regions in STEREO-A. We show that the observed intensities of the dimming regions in SDO/AIA depend on the structures that are lying along their LOS and are the combination of their individual intensities, e.g., the expanding CME body, the enhanced EUV wave, and the CME front. In this context, we conclude that the intermittent disappearance of the EUV wave in the AIA 171, 193, and 211 Å filters, which are channels sensitive to plasma with temperatures below ∼2 MK is also caused by such LOS integration effects. These observations clearly demonstrate that single-view image data provide us with limited insight to correctly interpret coronal features.

  11. Low color distortion adaptive dimming scheme for power efficient LCDs

    NASA Astrophysics Data System (ADS)

    Nam, Hyoungsik; Song, Eun-Ji

    2013-06-01

    This paper demonstrates the color compensation algorithm to reduce the color distortion caused by mismatches between the reference gamma value of a dimming algorithm and the display gamma values of an LCD panel in a low power adaptive dimming scheme. In 2010, we presented the YrYgYb algorithm, which used the display gamma values extracted from the luminance data of red, green, and blue sub-pixels, Yr, Yg, and Yb, with the simulation results. It was based on the ideal panel model where the color coordinates were maintained at the fixed values over the gray levels. Whereas, this work introduces an XrYgZb color compensation algorithm which obtains the display gamma values of red, green, and blue from the different tri-stimulus data of Xr, Yg, and Zb, to obtain further reduction on the color distortion. Both simulation and measurement results ensure that a XrYgZb algorithm outperforms a previous YrYgYb algorithm. In simulation which has been conducted at the practical model derived from the measured data, the XrYgZb scheme achieves lower maximum and average color difference values of 3.7743 and 0.6230 over 24 test picture images, compared to 4.864 and 0.7156 in the YrYgYb one. In measurement of a 19-inch LCD panel, the XrYgZb method also accomplishes smaller color difference values of 1.444072 and 5.588195 over 49 combinations of red, green, and blue data, compared to 1.50578 and 6.00403 of the YrYgYb at the backlight dimming ratios of 0.85 and 0.4.

  12. Is global dimming and brightening limited to urban areas?

    NASA Astrophysics Data System (ADS)

    Tanaka, Katsumasa; Imamovic, Adel; Folini, Doris; Ohmura, Atsumu; Wild, Martin

    2013-04-01

    Efforts have been put into place for decades around the world to understand the surface energy budget of the Earth. One of the pillars of such activities is the Global Energy Balance Archive (GEBA) project (Ohmura and Lang 1989), which established a database for the measurements of Surface Solar Radiation (SSR) and other parameters around the world. A major finding from the GEBA project is "global dimming and brightening" (Ohmura and Lang 1989; Wild 2009), which refers originally to the secular trend of SSR on the decadal time scale in Europe that had declined till around 1980s and then has been rising ever since. Secular trends have also been found elsewhere in the world, but the strength and the direction of the trend differ across regions (Ohmura 2009; Skeie et al. 2011; Wild et al. 2005). As a number of observations are made in or close to urban areas, speculations have arisen that the observed SSR trends may be influenced by local atmospheric pollution (with the direct aerosol effects being predominant (Kvalevåg and Myhre 2007)) and also by enhanced cloud cover over urban areas (Shepherd 2005). Thus, this raises a question: to what extent the observed global dimming and brightening is limited to urban areas. To date, only a few studies address this problem including a statistical study based on population data (Alpert et al. 2005) and model studies inspecting SSR trends (e.g. Dwyer et al. 2010; Skeie et al. 2011). Answers are, however, inconclusive and remain debated. We investigate whether the observed global dimming and brightening is a large scale phenomenon or limited to urban areas by using the following two complementary approaches: 1) We focus on a set of selected 14 stations in Japan that yield various high quality measurements since 1961 with three of them being least influenced by urbanization (based on expert elicitation). We look into seasonal time-series of SSR, cloud amount, and sunshine duration (Source: Japanese Meteorological Agency) as well

  13. Group statistical channel coding dimming scheme in visible light communication system

    NASA Astrophysics Data System (ADS)

    Zhuang, Kaiyu; Huang, Zhitong; Zhang, Ruqi; Li, Jianfeng; Ji, Yuefeng

    2016-10-01

    In this paper, we propose a group statistical channel coding (GSCC) scheme, which achieves dimming by changing the ratio of the 0-1 symbol of the original data stream through probabilistic statistics method. The simulation under various brightness conditions displays that the GSCC maintains good performance comparing to PWM dimming with half satisfice of transmission rate and a larger dimming intensity. Simulation of GSCC after combining with other channel coding schemes reflects that GSCC has good compatibility to arbitrary access coded signal.

  14. Exercise attenuates the metabolic effects of dim light at night.

    PubMed

    Fonken, Laura K; Meléndez-Fernández, O Hecmarie; Weil, Zachary M; Nelson, Randy J

    2014-01-30

    Most organisms display circadian rhythms that coordinate complex physiological and behavioral processes to optimize energy acquisition, storage, and expenditure. Disruptions to the circadian system with environmental manipulations such as nighttime light exposure alter metabolic energy homeostasis. Exercise is known to strengthen circadian rhythms and to prevent weight gain. Therefore, we hypothesized providing mice a running wheel for voluntary exercise would buffer against the effects of light at night (LAN) on weight gain. Mice were maintained in either dark (LD) or dim (dLAN) nights and provided either a running wheel or a locked wheel. Mice exposed to dim, rather than dark, nights increased weight gain. Access to a functional running wheel prevented body mass gain in mice exposed to dLAN. Voluntary exercise appeared to limit weight gain independently of rescuing changes to the circadian system caused by dLAN; increases in daytime food intake induced by dLAN were not diminished by increased voluntary exercise. Furthermore, although all of the LD mice displayed a 24h rhythm in wheel running, nearly half (4 out of 9) of the dLAN mice did not display a dominant 24h rhythm in wheel running. These results indicate that voluntary exercise can prevent weight gain induced by dLAN without rescuing circadian rhythm disruptions.

  15. Global Dimming and brightening: an update beyond 2000

    SciTech Connect

    Wild, Martin F.; Trussel, Barbara; Ohmura, Atsumu; Long, Charles N.; Konig-Langlo, G.; Dutton, Ellsworth G.; Tsvetkov, Anatoly V.

    2009-05-16

    This study investigates the recent variations in surface solar radiation inferred from a comprehensive set of ground-based observational records updated to 2005. Surface radiation data beyond 2000 are thereby particularly interesting, as they can provide independent and complementary information to the ambitious satellite programs which became operational after 2000. The surface records suggest a continuation of the upward tendency in surface solar radiation (“brightening”) beyond 2000 at numerous stations in Europe and in the US as well as parts of East Asia (Korea). The upward tendency in Antarctica over the 1990s, largely caused by a recovery from the high turbitity induced by the mount Pinatubo volcanic eruption, seem to fade after 2000. The brightening tendency also seems to level off in Japan. In China there is some indication for a renewed decline in dimming, after the stabilization in the 1990s. A continuation of the long lasting dimming is also noted at the sites in India. Overall, the available data suggest also beyond 2000 a widespread continuation of the brightening at many location, which is, however, less pronounced and homogeneous than during the 1990s.

  16. From Solar Dimming to Solar Brightening: Observations, Modeling, Impacts

    NASA Astrophysics Data System (ADS)

    Wild, M.; Ohmura, A.; Feichter, J.; Stier, P.; Robock, A.; Li, H.

    2005-12-01

    Recent evidence suggests that the amount of solar radiation reaching the earth surface is not stable over time but exhibits significant decadal variations. These variations, in addition to the changes in thermal radiation induced by alterations in greenhouse gases, cause changes in radiative forcings which may significantly affect surface climate. Observations from the Global Energy Balanced Archive (GEBA) and Baseline Surface Radiation Network (BSRN) databases at the Swiss Federal Institute of Technology suggest that surface solar radiation, after decades of dimming, reversed into a brightening since the mid 1980s at widespread locations. These changes are in line with a recovery of atmospheric transparency, possibly related to reduced aerosol loadings due to air pollution control and the breakdown of industry in formerly Communist countries. Not many GCMs currently represent aerosol effects with a degree of sophistication to capture such effects, but we used a special version of the Max Planck Institute for Meteorology GCM which includes a detailed aerosol scheme, ECHAM5-HAM, to investigate the observed trends. In addition, we investigate the potential impact of the variations in surface radiation on other elements of the climate system, such as soil moisture, which shows changes in line with the changes in radiation. Reference: Wild, M., Gilgen, H., Roesch, A., Ohmura, A., Long, C., Dutton, E., Forgan, B., Kallis, A., Russak, V., Tsvetkov, A., 2005: From dimming to brightening: Decadal changes in solar radiation at the Earth's surface. Science , 308, 847-850

  17. Dimming over the Oceans: Transient Anthropogenic Aerosol Plumes in the 20th Century

    NASA Astrophysics Data System (ADS)

    Dallafior, Tanja; Folini, Doris; Knutti, Reto; Wild, Martin

    2015-04-01

    Anthropogenic aerosols reduce incoming surface solar radiation (SSR), but the magnitude of this effect for reducing sea surface temperature (SST) is still debated. Using simulations from the global climate model ECHAM5 with the Hamburg Aerosol Module (HAM) and prescribed SSTs, we quantify anthropogenic aerosol dimming over sea surfaces by comparing ensembles, which only differ in anthropogenic aerosol emissions. We isolate the anthropogenic aerosol effect on SSR with sufficiently large ensemble sizes to provide statistically significant results. The following simulation results are obtained: Dimming plumes extend from their source regions with clear seasonality. The latter is predominantly shaped by atmospheric circulation, while interdecadal changes follow the gradual increase in anthropogenic aerosol emissions. Comparing the 1990s with the 1870s, on average, 9.4% (clearsky SSR) or 15.4% (allsky SSR) of the entire ocean surface was affected by anthropogenic aerosol dimming larger than -4 W m-2 (annual mean). Comparing the same time periods, global average anthropogenic dimming over oceans is -2.3 W m-2and -3.4 W m-2 for clearsky and allsky SSR, respectively. Surface dimming is hemispherically asymmetrical with stronger Northern Hemispheric dimming by 2.3 W m-2 and 4.5 W m-2 for clearsky and allsky SSR, respectively. Zonal average clearsky dimming reaches its maximum (5.5 W m-2 ) near the Equator. Allsky dimming peaks at 40° N (-8 W m-2 ) and is regionally larger than clearsky dimming. Regionally, surface dimming can go beyond -20 W m-2 (clearsky) and -40 W m-2 (allsky). Results are a contribution towards better quantifying spatially heterogeneous and time-dependent anthropogenic dimming effects on SSTs.

  18. Dimming over the oceans: Transient anthropogenic aerosol plumes in the twentieth century

    NASA Astrophysics Data System (ADS)

    Dallafior, T. N.; Folini, D.; Knutti, R.; Wild, M.

    2015-04-01

    Anthropogenic aerosols reduce incoming surface solar radiation (SSR), but the magnitude of this effect for reducing sea surface temperatures (SST) is still debated. Using simulations from the global climate model ECHAM5 with the Hamburg Aerosol Module and prescribed SSTs, we quantify anthropogenic aerosol dimming over sea surfaces by comparing ensembles, which only differ in anthropogenic aerosol emissions. We isolate the anthropogenic aerosol effect on SSR with sufficiently large ensemble sizes to provide statistically significant results. The following simulation results are obtained: Dimming plumes extend from their source regions with clear seasonality. The latter is predominantly shaped by atmospheric circulation, while interdecadal changes follow the gradual increase in anthropogenic aerosol emissions. Comparing the 1990s with the 1870s, on average, 9.4% (clear-sky SSR) or 15.4% (all-sky SSR) of the entire ocean surface was affected by anthropogenic aerosol dimming larger than -4 Wm-2 (decadal mean). Comparing the same time periods, global average anthropogenic dimming over oceans is -2.3 Wm-2 and -3.4 Wm-2 for clear-sky and all-sky SSR, respectively. Surface dimming is hemispherically asymmetrical with stronger Northern Hemispheric dimming by 2.3 Wm-2 and 4.5 Wm-2 for clear-sky and all-sky SSR, respectively. Zonal average clear-sky dimming reaches its maximum (-5.5 Wm-2) near the equator. All-sky dimming peaks at 40°N (-8 Wm-2) and is regionally larger than clear-sky dimming. Regionally, surface dimming can reach values up to 9.5 Wm-2 (clear-sky) and 25 Wm-2 (all-sky). Results are a contribution toward better quantifying spatially heterogeneous and time-dependent anthropogenic dimming effects on SSTs.

  19. Evaluation of a new optic-enabled portable X-ray fluorescence spectrometry instrument for measuring toxic metals/metalloids in consumer goods and cultural products

    NASA Astrophysics Data System (ADS)

    Guimarães, Diana; Praamsma, Meredith L.; Parsons, Patrick J.

    2016-08-01

    X-ray fluorescence spectrometry (XRF) is a rapid, non-destructive multi-elemental analytical technique used for determining elemental contents ranging from percent down to the μg/g level. Although detection limits are much higher for XRF compared to other laboratory-based methods, such as inductively coupled plasma mass spectrometry (ICP-MS), ICP-optical emission spectrometry (OES) and atomic absorption spectrometry (AAS), its portability and ease of use make it a valuable tool, especially for field-based studies. A growing necessity to monitor human exposure to toxic metals and metalloids in consumer goods, cultural products, foods and other sample types while performing the analysis in situ has led to several important developments in portable XRF technology. In this study, a new portable XRF analyzer based on the use of doubly curved crystal optics (HD Mobile®) was evaluated for detecting toxic elements in foods, medicines, cosmetics and spices used in many Asian communities. Two models of the HD Mobile® (a pre-production and a final production unit) were investigated. Performance parameters including accuracy, precision and detection limits were characterized in a laboratory setting using certified reference materials (CRMs) and standard solutions. Bias estimates for key elements of public health significance such as As, Cd, Hg and Pb ranged from - 10% to 11% for the pre-production, and - 14% to 16% for the final production model. Five archived public health samples including herbal medicine products, ethnic spices and cosmetic products were analyzed using both XRF instruments. There was good agreement between the pre-production and final production models for the four key elements, such that the data were judged to be fit-for-purpose for the majority of samples analyzed. Detection of the four key elements of interest using the HD Mobile® was confirmed using archived samples for which ICP-OES data were available based on digested sample materials. The HD

  20. Evolution of dim-light and color vision pigments.

    PubMed

    Yokoyama, Shozo

    2008-01-01

    A striking level of diversity of visual systems in different species reflects their adaptive responses to various light environments. To study the adaptive evolution of visual systems, we need to understand how visual pigments, the light-sensitive molecules, have tuned their wavelengths of light absorption. The molecular basis of spectral tuning in visual pigments, a central unsolved problem in phototransduction, can be understood only by studying how different species have adapted to various light environments. Certain amino acid replacements at 30 residues explain some dim-light and color vision in vertebrates. To better understand the molecular and functional adaptations of visual pigments, we must identify all critical amino acid replacements that are involved in the spectral tuning and elucidate the effects of their interactions on the spectral shifts.

  1. Small and dim target detection by background estimation

    NASA Astrophysics Data System (ADS)

    Hu, Jing; Yu, Yi; Liu, Fan

    2015-11-01

    An effective method for small and dim moving target detection in complicated background is proposed. The proposed approach takes advantage of the Non-local means filter, and applies a novel weight calculation model based on circular mask to the original background estimation pattern. By associating similarity of grayscale distribution of the images with temporal information, the extended method estimates the complicated background precisely and extracts point target successfully. To compare existing target detection methods and the proposed one, signal-to-clutter ratio gain (SCRG) and background suppression factor (BSF) are employed for spatial performance comparison and receiver operating characteristics (ROC) is used for detection-performance comparison of the target trajectory. Experimental results demonstrate good performance of the proposed method for infrared images in complicated scene, especially for images with low signal-to-noise ratio.

  2. A quantitative dimming method for LED based on PWM

    NASA Astrophysics Data System (ADS)

    Wang, Jiyong; Mou, Tongsheng; Wang, Jianping; Tian, Xiaoqing

    2012-10-01

    Traditional light sources were required to provide stable and uniform illumination for a living or working environment considering performance of visual function of human being. The requirement was always reasonable until non-visual functions of the ganglion cells in the retina photosensitive layer were found. New generation of lighting technology, however, is emerging based on novel lighting materials such as LED and photobiological effects on human physiology and behavior. To realize dynamic lighting of LED whose intensity and color were adjustable to the need of photobiological effects, a quantitative dimming method based on Pulse Width Modulation (PWM) and light-mixing technology was presented. Beginning with two channels' PWM, this paper demonstrated the determinacy and limitation of PWM dimming for realizing Expected Photometric and Colorimetric Quantities (EPCQ), in accordance with the analysis on geometrical, photometric, colorimetric and electrodynamic constraints. A quantitative model which mapped the EPCQ into duty cycles was finally established. The deduced model suggested that the determinacy was a unique individuality only for two channels' and three channels' PWM, but the limitation was an inevitable commonness for multiple channels'. To examine the model, a light-mixing experiment with two kinds of white LED simulated variations of illuminance and Correlation Color Temperature (CCT) from dawn to midday. Mean deviations between theoretical values and measured values were obtained, which were 15lx and 23K respectively. Result shows that this method can effectively realize the light spectrum which has a specific requirement of EPCQ, and provides a theoretical basis and a practical way for dynamic lighting of LED.

  3. Automated Detection and Extraction of Coronal Dimmings from SDO/AIA Data

    NASA Astrophysics Data System (ADS)

    Davey, Alisdair R.; Attrill, G. D. R.; Wills-Davey, M. J.

    2010-05-01

    The sheer volume of data anticipated from the Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA) highlights the necessity for the development of automatic detection methods for various types of solar activity. Initially recognised in the 1970s, it is now well established that coronal dimmings are closely associated with coronal mass ejections (CMEs), and are particularly recognised as an indicator of front-side (halo) CMEs, which can be difficult to detect in white-light coronagraph data. An automated coronal dimming region detection and extraction algorithm removes visual observer bias from determination of physical quantities such as spatial location, area and volume. This allows reproducible, quantifiable results to be mined from very large datasets. The information derived may facilitate more reliable early space weather detection, as well as offering the potential for conducting large-sample studies focused on determining the geoeffectiveness of CMEs, coupled with analysis of their associated coronal dimmings. We present examples of dimming events extracted using our algorithm from existing EUV data, demonstrating the potential for the anticipated application to SDO/AIA data. Metadata returned by our algorithm include: location, area, volume, mass and dynamics of coronal dimmings. As well as running on historic datasets, this algorithm is capable of detecting and extracting coronal dimmings in near real-time. The coronal dimming detection and extraction algorithm described in this poster is part of the SDO/Computer Vision Center effort hosted at SAO (Martens et al., 2009). We acknowledge NASA grant NNH07AB97C.

  4. Relationship of EUV Irradiance Coronal Dimming Slope and Depth to Coronal Mass Ejection Speed and Mass

    NASA Astrophysics Data System (ADS)

    Mason, James Paul; Woods, Thomas N.; Webb, David F.; Thompson, Barbara J.; Colaninno, Robin C.; Vourlidas, Angelos

    2016-10-01

    Extreme ultraviolet (EUV) coronal dimmings are often observed in response to solar eruptive events. These phenomena can be generated via several different physical processes. For space weather, the most important of these is the temporary void left behind by a coronal mass ejection (CME). Massive, fast CMEs tend to leave behind a darker void that also usually corresponds to minimum irradiance for the cooler coronal emissions. If the dimming is associated with a solar flare, as is often the case, the flare component of the irradiance light curve in the cooler coronal emission can be isolated and removed using simultaneous measurements of warmer coronal lines. We apply this technique to 37 dimming events identified during two separate two-week periods in 2011 plus an event on 2010 August 7, analyzed in a previous paper to parameterize dimming in terms of depth and slope. We provide statistics on which combination of wavelengths worked best for the flare-removal method, describe the fitting methods applied to the dimming light curves, and compare the dimming parameters with corresponding CME parameters of mass and speed. The best linear relationships found are \\begin{eqnarray*}{v}{CME} ≤ft[\\displaystyle \\frac{{km}}{{{s}}}\\right] & ≈ & 2.36× {10}6 ≤ft[\\displaystyle \\frac{{km}}{ % }\\right]× {s}\\dim ≤ft[\\displaystyle \\frac{ % }{{{s}}}\\right]\\ {m}{CME} [{{g}}] & ≈ & 2.59× {10}15≤ft[\\displaystyle \\frac{g}{ % }\\right]× \\sqrt{{d}\\dim } [ % ].\\end{eqnarray*} These relationships could be used for space weather operations of estimating CME mass and speed using near-real-time irradiance dimming measurements.

  5. Dim 6 nucleon decay in anomalous U(1){sub A} SUSY GUT

    SciTech Connect

    Muramatsu, Yu

    2012-07-27

    Anomalous U(1){sub A} SUSY GUT models are atractive because they can solve many difficulties in SUSY GUT models. In anomalous U(1){sub A} SUSY GUT models, nucleon decay amplitudes of dim 6 effective interactions are larger than that of dim 5 effective interactions. Then, I discuss dim 6 effective interactions in some models, and predict proton lifetimes for many decay modes by calculating interactions. First, I fix unitary matrices that make Yukawa coupling matrices diagonalize, and predict proton lifetimes. Second, I study uncertainties of these unitary matrices, and show these effects on proton lifetimes. From these results, I show that we can distinguish some models from by nucleon decay.

  6. Dimming LEDs with Phase-Cut Dimmers. The Specifier's Process for Maximizing Success

    SciTech Connect

    Miller, N. J.; Poplawski, M. E.

    2013-10-01

    DOE GATEWAY program report reviewing how phase-cut dimmers work, how LEDs differ from the incandescent lamps these dimmers were originally designed to control, and how those differences can lead to complications when attempting to dim LEDs. Providing both general guidance and step-by-step procedures for designing phase-controlled LED dimming on both new and existing projects—as well as real-world examples of how to use those procedures—the report aims to reduce the chance of experiencing compatibility-related problems and, if possible, ensure good dimming performance.

  7. 3,3'-Diindolylmethane (DIM) and its ring-substituted halogenated analogs (ring-DIMs) induce differential mechanisms of survival and death in androgen-dependent and -independent prostate cancer cells.

    PubMed

    Goldberg, Alexander A; Draz, Hossam; Montes-Grajales, Diana; Olivero-Verbél, Jesus; Safe, Stephen H; Sanderson, J Thomas

    2015-05-01

    We recently reported that novel ring-substituted analogs of 3,3'-diindolylmethane (ring-DIMs) induce apoptosis and necrosis in androgen-dependent and -independent prostate cancer cells. In this paper, we have focused on the mechanism(s) associated with ring-DIM-mediated cell death, and on identifying the specific intracellular target(s) of these compounds. The 4,4'- and 7,7'-dichloroDIMs and 4,4'- and 7,7'-dibromoDIMs induced the death of LNCaP, C42B and DU145 prostate cancer cells, but not that of immortalized normal human prostate epithelial (RWPE-1) cells. Ring-DIMs caused the early loss of mitochondrial membrane potential (MMP) and decreased mitochondrial ATP generation in prostate cancer cells. Cyclosporin A, an inhibitor of the mitochondrial permeability transition pore, inhibited ring-DIM-mediated cell death, and salubrinal, an inhibitor of ER stress, inhibited cell death mediated only by 4,4'-dihaloDIMs. We found that although salubrinal did not inhibit the onset of ER stress, it prevented 4,4'-dibromoDIM mediated loss of MMP. Salubrinal potentiated cell death in response to 7,7'-dihaloDIMs and DIM, and this effect concurred with increased loss of MMP. Using in silico 3-D docking affinity analysis, we identified Ca2+/calmodulin-dependent kinase II (CaMKII) as a potential direct target for the most toxic ring-DIM, 4,4'-dibromoDIM. An inhibitor of CaMKII, KN93, but not its inactive analog KN92, abrogated cell death mediated by 4,4'-dibromoDIM. The ring-DIMs induced ER stress and autophagy, but these processes were not necessary for ring-DIM-mediated cell death. Inhibition of autophagy with bafilomycin A1, 3-methyladenine or by LC3B gene silencing sensitized LNCaP and C42B, but not ATG5-deficient DU145 cells to ring-DIM- and DIM-mediated cell death. We propose that autophagy induced by the ring-DIMs and DIM has a cytoprotective function in prostate cancer cells. PMID:26124925

  8. 3,3′-Diindolylmethane (DIM) and its ring-substituted halogenated analogs (ring-DIMs) induce differential mechanisms of survival and death in androgen-dependent and –independent prostate cancer cells

    PubMed Central

    Montes-Grajales, Diana; Olivero-Verbél, Jesus; Safe, Stephen H.; Sanderson, J. Thomas

    2015-01-01

    We recently reported that novel ring-substituted analogs of 3,3′-diindolylmethane (ring-DIMs) induce apoptosis and necrosis in androgen-dependent and –independent prostate cancer cells. In this paper, we have focused on the mechanism(s) associated with ring-DIM-mediated cell death, and on identifying the specific intracellular target(s) of these compounds. The 4,4′- and 7,7′-dichloroDIMs and 4,4′- and 7,7′-dibromoDIMs induced the death of LNCaP, C42B and DU145 prostate cancer cells, but not that of immortalized normal human prostate epithelial (RWPE-1) cells. Ring-DIMs caused the early loss of mitochondrial membrane potential (MMP) and decreased mitochondrial ATP generation in prostate cancer cells. Cyclosporin A, an inhibitor of the mitochondrial permeability transition pore, inhibited ring-DIM-mediated cell death, and salubrinal, an inhibitor of ER stress, inhibited cell death mediated only by 4,4′-dihaloDIMs. We found that although salubrinal did not inhibit the onset of ER stress, it prevented 4,4′-dibromoDIM mediated loss of MMP. Salubrinal potentiated cell death in response to 7,7′-dihaloDIMs and DIM, and this effect concurred with increased loss of MMP. Using in silico 3-D docking affinity analysis, we identified Ca2+/calmodulin-dependent kinase II (CaMKII) as a potential direct target for the most toxic ring-DIM, 4,4′-dibromoDIM. An inhibitor of CaMKII, KN93, but not its inactive analog KN92, abrogated cell death mediated by 4,4′-dibromoDIM. The ring-DIMs induced ER stress and autophagy, but these processes were not necessary for ring-DIM-mediated cell death. Inhibition of autophagy with bafilomycin A1, 3-methyladenine or by LC3B gene silencing sensitized LNCaP and C42B, but not ATG5-deficient DU145 cells to ring-DIM- and DIM-mediated cell death. We propose that autophagy induced by the ring-DIMs and DIM has a cytoprotective function in prostate cancer cells. PMID:26124925

  9. Bumblebees Perform Well-Controlled Landings in Dim Light

    PubMed Central

    Reber, Therese; Dacke, Marie; Warrant, Eric; Baird, Emily

    2016-01-01

    To make a smooth touchdown when landing, an insect must be able to reliably control its approach speed as well as its body and leg position—behaviors that are thought to be regulated primarily by visual information. Bumblebees forage and land under a broad range of light intensities and while their behavior during the final moments of landing has been described in detail in bright light, little is known about how this is affected by decreasing light intensity. Here, we investigate this by characterizing the performance of bumblebees, B. terrestris, landing on a flat platform at two different orientations (horizontal and vertical) and at four different light intensities (ranging from 600 lx down to 19 lx). As light intensity decreased, the bees modified their body position and the distance at which they extended their legs, suggesting that the control of landing in these insects is visually mediated. Nevertheless, the effect of light intensity was small and the landings were still well controlled, even in the dimmest light. We suggest that the changes in landing behavior that occurred in dim light might represent adaptations that allow the bees to perform smooth landings across the broad range of light intensities at which they are active. PMID:27683546

  10. Bumblebees Perform Well-Controlled Landings in Dim Light.

    PubMed

    Reber, Therese; Dacke, Marie; Warrant, Eric; Baird, Emily

    2016-01-01

    To make a smooth touchdown when landing, an insect must be able to reliably control its approach speed as well as its body and leg position-behaviors that are thought to be regulated primarily by visual information. Bumblebees forage and land under a broad range of light intensities and while their behavior during the final moments of landing has been described in detail in bright light, little is known about how this is affected by decreasing light intensity. Here, we investigate this by characterizing the performance of bumblebees, B. terrestris, landing on a flat platform at two different orientations (horizontal and vertical) and at four different light intensities (ranging from 600 lx down to 19 lx). As light intensity decreased, the bees modified their body position and the distance at which they extended their legs, suggesting that the control of landing in these insects is visually mediated. Nevertheless, the effect of light intensity was small and the landings were still well controlled, even in the dimmest light. We suggest that the changes in landing behavior that occurred in dim light might represent adaptations that allow the bees to perform smooth landings across the broad range of light intensities at which they are active. PMID:27683546

  11. Bumblebees Perform Well-Controlled Landings in Dim Light

    PubMed Central

    Reber, Therese; Dacke, Marie; Warrant, Eric; Baird, Emily

    2016-01-01

    To make a smooth touchdown when landing, an insect must be able to reliably control its approach speed as well as its body and leg position—behaviors that are thought to be regulated primarily by visual information. Bumblebees forage and land under a broad range of light intensities and while their behavior during the final moments of landing has been described in detail in bright light, little is known about how this is affected by decreasing light intensity. Here, we investigate this by characterizing the performance of bumblebees, B. terrestris, landing on a flat platform at two different orientations (horizontal and vertical) and at four different light intensities (ranging from 600 lx down to 19 lx). As light intensity decreased, the bees modified their body position and the distance at which they extended their legs, suggesting that the control of landing in these insects is visually mediated. Nevertheless, the effect of light intensity was small and the landings were still well controlled, even in the dimmest light. We suggest that the changes in landing behavior that occurred in dim light might represent adaptations that allow the bees to perform smooth landings across the broad range of light intensities at which they are active.

  12. Bumblebees Perform Well-Controlled Landings in Dim Light.

    PubMed

    Reber, Therese; Dacke, Marie; Warrant, Eric; Baird, Emily

    2016-01-01

    To make a smooth touchdown when landing, an insect must be able to reliably control its approach speed as well as its body and leg position-behaviors that are thought to be regulated primarily by visual information. Bumblebees forage and land under a broad range of light intensities and while their behavior during the final moments of landing has been described in detail in bright light, little is known about how this is affected by decreasing light intensity. Here, we investigate this by characterizing the performance of bumblebees, B. terrestris, landing on a flat platform at two different orientations (horizontal and vertical) and at four different light intensities (ranging from 600 lx down to 19 lx). As light intensity decreased, the bees modified their body position and the distance at which they extended their legs, suggesting that the control of landing in these insects is visually mediated. Nevertheless, the effect of light intensity was small and the landings were still well controlled, even in the dimmest light. We suggest that the changes in landing behavior that occurred in dim light might represent adaptations that allow the bees to perform smooth landings across the broad range of light intensities at which they are active.

  13. Dim2p, a KH-domain protein required for small ribosomal subunit synthesis

    PubMed Central

    VANROBAYS, EMMANUEL; GÉLUGNE, JEAN-PAUL; CAIZERGUES-FERRER, MICHÈLE; LAFONTAINE, DENIS L.J.

    2004-01-01

    Recent proteomic analyses are revealing the dynamics of preribosome assembly. Following cleavage at processing site A2, which generates the 20S pre-rRNA (the immediate precursor to the 18S rRNA), early RRPs (ribosomal RNA processing factors) are released in bulk from the preribosomes, and the resulting pre-40S subunits are left associated with a limited set of proteins that we refer to as the SSU RRP complex. Dim2p, a core constituent of the SSU RRP complex and conserved KH-domain containing protein, is required for pre-rRNA processing and is associated with early nucleolar and late cytoplasmic pre-rRNA species. Consistently, Dim2p shuttles between the nucle(ol)us and the cytoplasm, a trafficking that is tightly regulated by growth. The association of Dim2p with the 18S rRNA dimethyltransferase Dim1p, as well as its requirement for pre-rRNA processing at cleavage sites A1 and A2 and for 18S rRNA dimethylation, suggest that Dim2p may recruit Dim1p to nucleolar pre-rRNAs through its KH domain. PMID:15037774

  14. Responses of young Xenopus laevis tadpoles to light dimming: possible roles for the pineal eye.

    PubMed

    Jamieson, D; Roberts, A

    2000-06-01

    When the light is dimmed, the pineal eye of hatchling Xenopus laevis tadpoles excites the central pattern generator for swimming, but the behavioural significance of pineal excitation is unclear. We show that tadpoles spend 99 % of their time hanging from the surface meniscus or solid objects using mucus secreted by a cement gland on the head. Attachment inhibits swimming, but unattached tadpoles swim spontaneously. Provided that their pineal eye is intact, they attach closer to the water surface in the dark than in the light and attach preferentially to the underside of floating objects that cast shadows. Dimming causes tadpoles swimming horizontally to turn upwards and is very effective in initiating upward swimming in unattached tadpoles. Similar pineal-dependent responses during swimming are present up to stage 44. Pinealectomy blocks responses to dimming at all stages. Recordings from immobilised tadpoles reveal that light dimming induces faster fictive swimming and that pineal activity is increased for up to 20 min during sustained light dimming. We suggest that the increase in pineal discharge during dimming increases the probability of upward swimming and, in this way, increases the probability of tadpoles attaching to objects higher in the water column that cast shadows.

  15. The color of night: Surface color perception under dim illuminations.

    PubMed

    Pokorny, Joel; Lutze, Margaret; Cao, Dingcai; Zele, Andrew J

    2006-01-01

    Several studies document rudimentary color vision under dim illumination. Here, hue perceptions of paper color samples were determined for a wide range of light levels, including very low light levels where rods alone mediate vision. The appearances of 24 paper color samples from the OSA Uniform Color Scales were gauged under successively dimmer illuminations from 10-0.0003 Lux. Triads of samples were chosen representing each of eight basic color categories; red, pink, orange, yellow, green, blue, purple, and gray. Samples within each triad varied in lightness. Observers sorted samples into groups that they could categorize with specific color names. Above 0.32 Lux, observers sorted the samples into the originally chosen color groups with few exceptions. For 0.1-0.01 Lux, the red and orange samples were usually correctly identified as either red or orange. The remaining samples tended to be grouped into two categories, associated with the scotopic sample reflectance. The lowest reflectance samples were below threshold and were named black. The higher reflectance group was named predominately as green or blue-green (three observers; the fourth observer used blue or achromatic). At the three dimmest levels (< or = 0.0032 Lux) there continued to be conspicuous color percepts. Color categories were reliably assigned based on relative sample scotopic lightness. Of the samples above threshold, those with lower reflectance were classified as red or orange (all observers) and the higher reflectance samples as green or blue-green (three observers) or achromatic or blue (the fourth observer). Rods and L-cones presumably mediated color percepts at the intermediate light levels used in the study. At the three lowest light levels there were distinct color appearances mediated exclusively by rods. We speculate that at these light levels the visual system estimates probable colors based on prior natural experience. PMID:16961990

  16. Anthropogenic Aerosol Dimming Over Oceans: A Regional Analysis

    NASA Astrophysics Data System (ADS)

    Dallafior, T. N.; Folini, D.; Knutti, R.; Wild, M.

    2015-12-01

    The role of anthropogenic aerosols in shaping 20th century SSTs through alteration of surface solar radiation (SSR) is still subject to debate. Identifying and quantifying the relationship between aerosol-induced changes in SSR and the corresponding SST response is difficult due to the masking effect of numerous feedback mechanisms and general variability of the atmosphere-ocean system. We therefore analysed potential anthropogenic aerosol effects on SST with a cascade of experiments of increasing complexity: From atmosphere-only over mixed-layer ocean (MLO) experiments, to fully coupled transient ocean-atmosphere simulations, with and without greenhouse gases and / or aerosols, using the general circulation model ECHAM with explicit aerosol representation. We find anthropogenic aerosols to be crucial to obtain realistic SSR and SST patterns, although co-location of changes in individual variables (aerosol optical depth, SSR, SST) is weak. The effect of greenhouse gases and aerosols in the MLO simulations is essentially additive on global and regional scales, an assumption frequently made in the literature. With atmosphere-only simulations we identified regions most prone to anthropogenic aerosol dimming throughout the 20th century using a strict criterion. From MLO equilibria representative of different decades throughout the 20th century, we identified ocean regions, whose SSTs are most sensitive to changing anthropogenic aerosol emissions. The surface temperature response patterns in our MLO simulations are more sensitive towards the choice of prescribed deep-ocean heat flux if anthropogenic aerosols were included as compared to greenhouse gas only simulations. This implies that ocean dynamics might mask some of the response and cautions against the use of just one set of deep-ocean heat fluxes in MLO studies. Our results corroborate not only the relevance of anthropogenic aerosols for SST responses, but also highlight the complexity and non-locality of the

  17. Impact of Surface Solar Dimming and Brightening on the Climate System

    NASA Astrophysics Data System (ADS)

    Wild, M.

    2007-05-01

    The author's institute maintains two databases for the worldwide measured solar radiation incident at the Eart's surface, the Global Energy Balance Archive (GEBA), and the Baseline Surface Radiation Network (BSRN). An analysis of these comprehensive datasets suggests that solar radiation incident at the surface has not been stable over time but underwent significant decadal variations. This is seen in a decline in surface solar radiation from the 1960s to the 1980s ("global dimming"), with a recovery thereafter at widespread locations ("global brightening"). As potential explanation for these variations, both changes in clouds and aerosol have been put forward. An analysis of synop and satellite-based cloud data over Europe suggests, that changes in cloud amount cannot explain the distinct reversal from solar dimming to brightening seen over Europe. This points to aerosol direct/indirect effects as a key explanation for the dimming to brightening transition. The reversal from dimming to brightening may be related to reduced aerosol concentration due to more effective air pollution measures and the breakdown of the economy in the former communist countries, leading to cleaner and more transparent atmospheres. Changes in surface solar radiation may also leave their imprint in the diurnal temperature range. Trends in diurnal temperature ranges show, after decades of decline, a distinct tendency to level off since the mid 1980s. They suggest that surface solar dimming was effective in masking greenhouse warming, but only up to the 1980s, when dimming gradually transformed into brightening. With this transition, the uncovered greenhouse effect started to reveal its full dimension, as manifested in a rapid temperature rise. The reversal from surface solar dimming to brightening may also affect biomass productivity in energy-limited environments, and should leave a significant imprint on vegetation. Wild, M et al. 2005: From dimming to brightening: Decadal changes in

  18. Dust Impact Monitor DIM Onboard Philae: Measurements at Comet 67P/C-G

    NASA Astrophysics Data System (ADS)

    Krüger, Harald; Albin, Thomas; Apathy, Istvan; Arnold, Walter; Flandes, Alberto; Fischer, Hans-Herbert; Hirn, Attila; Loose, Alexander; Peter, Attila; Seidensticker, Klaus J.; Sperl, Matthias

    2015-04-01

    The Rosetta lander Philae landed successfully on the nucleus surface of comet 67P/Churyumov-Gerasimenko on 12 November 2014. Philae is equipped with the Dust Impact Monitor (DIM) which is part of the SESAME experiment package onboard. DIM employs piezoelectric PZT sensors to detect impacts by sub-millimetre and millimetre-sized ice and dust particles that are emitted from the nucleus and transported into the cometary coma. DIM was operated during Philae's descent to its nominal landing site at 4 different altitudes above the comet surface, and at Philae's final landing site. During descent to the nominal landing site, DIM measured the impact of one rather big particle that probably had a size of a few millimeters. No impacts were detected at the final landing site which may be due to low cometary activity or due to shadowing from obstacles close to Philae, or both. We will present the results from our measurements at the comet and compare them with laboratory calibration experiments with ice/dust particles performed with a DIM flight spare sensor.

  19. CD62L expression identifies a unique subset of polyfunctional CD56dim NK cells.

    PubMed

    Juelke, Kerstin; Killig, Monica; Luetke-Eversloh, Merlin; Parente, Eliana; Gruen, Joachim; Morandi, Barbara; Ferlazzo, Guido; Thiel, Andreas; Schmitt-Knosalla, Isabela; Romagnani, Chiara

    2010-08-26

    Human natural killer (NK) cells comprise 2 main subsets, CD56(bright) and CD56(dim) cells, that differ in function, phenotype, and tissue localization. To further dissect the heterogeneity of CD56(dim) cells, we have performed transcriptome analysis and functional ex vivo characterization of human NK-cell subsets according to the expression of markers related to differentiation, migration or competence. Here, we show for the first time that the ability to respond to cytokines or to activating receptors is mutually exclusive in almost all NK cells with the exception of CD56(dim) CD62L(+) cells. Indeed, only these cells combine the ability to produce interferon-gamma after cytokines and proliferate in vivo during viral infection with the capacity to kill and produce cytokines upon engagement of activating receptors. Therefore, CD56(dim) CD62L(+) cells represent a unique subset of polyfunctional NK cells. Ex vivo analysis of their function, phenotype, telomere length, frequencies during ageing as well as transfer experiments of NK-cell subsets into immunodeficient mice suggest that CD56(dim) CD62L(+) cells represent an intermediate stage of NK-cell maturation, which after restimulation can accomplish multiple tasks and further develop into terminally differentiated effectors.

  20. Mechanisms and observations of coronal dimming for the 201 August 7 event

    SciTech Connect

    Mason, James Paul; Woods, T. N.; Caspi, A.; Thompson, B. J.; Hock, R. A.

    2014-07-01

    Coronal dimming of extreme ultraviolet (EUV) emission has the potential to be a useful forecaster of coronal mass ejections (CMEs). As emitting material leaves the corona, a temporary void is left behind which can be observed in spectral images and irradiance measurements. The velocity and mass of the CMEs should impact the character of those observations. However, other physical processes can confuse the observations. We describe these processes and the expected observational signature, with special emphasis placed on the differences. We then apply this understanding to a coronal dimming event with an associated CME that occurred on 2010 August 7. Data from the Solar Dynamics Observatory's Atmospheric Imaging Assembly and EUV Variability Experiment (EVE) are used for observations of the dimming, while the Solar and Heliospheric Observatory's Large Angle and Spectrometric Coronagraph and the Solar Terrestrial Relations Observatory's COR1 and COR2 are used to obtain velocity and mass estimates for the associated CME. We develop a technique for mitigating temperature effects in coronal dimming from full-disk irradiance measurements taken by EVE. We find that for this event, nearly 100% of the dimming is due to mass loss in the corona.

  1. The effect of surface brightness dimming in the selection of high-z galaxies

    SciTech Connect

    Calvi, V.; Stiavelli, M.; Bradley, L.; Pizzella, A.; Kim, S.

    2014-12-01

    Cosmological surface brightness (SB) dimming of the form (1 + z){sup –4} affects all sources. The strong dependence of SB dimming on redshift z suggests the presence of a selection bias when searching for high-z galaxies, i.e., we tend to detect only those galaxies with a high SB. However, unresolved knots of emission are not affected by SB dimming, thus providing a way to test the clumpiness of high-z galaxies. Our strategy relies on the comparison of the total flux detected for the same source in surveys characterized by different depth. For all galaxies, deeper images permit the better investigation of low-SB features. Cosmological SB dimming makes these low-SB features hard to detect when going to higher and higher redshifts. We used the GOODS and HUDF Hubble Space Telescope legacy data sets to study the effect of SB dimming on low-SB features of high-z galaxies and compare it to the prediction for smooth sources. We selected a sample of Lyman-break galaxies at z ∼ 4 (i.e., B {sub 435}-band dropouts) detected in all of the data sets and found no significant trend when comparing the total magnitudes measured from images with different depth. Through Monte Carlo simulations we derived the expected trend for galaxies with different SB profiles. The comparison to the data hints at a compact distribution for most of the rest-frame ultraviolet light emitted from high-z galaxies.

  2. Mechanisms and Observations of Coronal Dimming for the 2010 August 7 Event

    NASA Technical Reports Server (NTRS)

    Mason, James P.; Woods, Thomas N.; Caspi, Amir; Thompson, Barbara J.; Hock, Rachel A.

    2014-01-01

    Coronal dimming of extreme ultraviolet (EUV) emission has the potential to be a useful forecaster of coronal mass ejections (CMEs). As emitting material leaves the corona, a temporary void is left behind which can be observed in spectral images and irradiance measurements. The velocity and mass of the CMEs should impact the character of those observations. However, other physical processes can confuse the observations. We describe these processes and the expected observational signature, with special emphasis placed on the differences. We then apply this understanding to a coronal dimming event with an associated CME that occurred on 2010 August 7. Data from the Solar Dynamics Observatory's (SDO) Atmospheric Imaging Assembly (AIA) and EUV Variability Experiment (EVE) are used for observations of the dimming, while the Solar and Heliospheric Observatory's (SoHO) Large Angle and Spectrometric Coronagraph (LASCO) and the Solar Terrestrial Relations Observatory's (STEREO) COR1 and COR2 are used to obtain velocity and mass estimates for the associated CME. We develop a technique for mitigating temperature effects in coronal dimming from full-disk irradiance measurements taken by EVE. We find that for this event, nearly 100% of the dimming is due to mass loss in the corona.

  3. Subjective comparison of brightness preservation methods for local backlight dimming displays

    NASA Astrophysics Data System (ADS)

    Korhonen, J.; Mantel, C.; Forchhammer, S.

    2015-01-01

    Local backlight dimming is a popular technology in high quality Liquid Crystal Displays (LCDs). In those displays, the backlight is composed of contributions from several individually adjustable backlight segments, set at different backlight luminance levels in different parts of the screen, according to the luma of the target image displayed on LCD. Typically, transmittance of the liquid crystal cells (pixels) located in the regions with dimmed backlight is increased in order to preserve their relative brightness with respect to the pixels located in the regions with bright backlight. There are different methods for brightness preservation for local backlight dimming displays, producing images with different visual characteristics. In this study, we have implemented, analyzed and evaluated several different approaches for brightness preservation, and conducted a subjective study based on rank ordering to compare the relevant methods on a real-life LCD with a local backlight dimming capability. In general, our results show that locally adapted brightness preservation methods produce more preferred visual outcome than global methods, but dependency on the content is also observed. Based on the results, guidelines for selecting the perceptually preferred brightness preservation method for local backlight dimming displays are outlined.

  4. Impact of submerged aquatic macrophytes on 3-dim current systems and hydrodynamic transport processes in Lake Constance

    NASA Astrophysics Data System (ADS)

    Wolf, Thomas; Lüddeke, Frauke; Thiange, Christophe

    2015-04-01

    According to the assessment criteria of the European water framework directive Lake Constance is having a good water quality. Nevertheless upcoming criteria using environmental quality measures show that there are still problems with respect to micropollutants. In fact, we observe significantly enhanced concentrations of micropollutants close to river mouths and in the areas of shallow water zones within Lake Constance compared to deep water concentrations. These findings are caused by river water plumes which can flow over distances of kilometers in the lake without being diluted or mixed only weakly with the surrounding lake water body. Besides, in the area of interest exist large populations of submerged aquatic macrophytes (SAM). There is only little knowledge, how these influence the distribution and transport processes of micropollutants. In order to assess the impact and distribution of river water plumes in different areas of the lake we implemented a 3-dim hydrodynamic model using DELFT3D-FLOW on a locally refined numerical grid which enables to cover different process scales of the distribution of river water bodies ranging from a few meters up to basin wide scales in the order of a few kilometers. We used numerical tracers (conservative and non-conservative) in order to quantify the impact of different abstract substance classes which are distinguished by their decay rates. In order to asses the influence of SAM populations on current field and transport processes we used a special simulation technique - the trachytope concept. The results of our 3-dim hydrodynamic model showed significantly changed current velocities, residence times and age of water parameters within the SAM areas compared to the control simulation without SAM. By simulating the propagation of coliform bacteria using numerical tracers with spatially and temporarily variable decay rates, we found complex impact pattern of the SAM on the distribution of these potentially harmful

  5. Dust Impact Monitor (SESAME-DIM) measurements at comet 67P/Churyumov-Gerasimenko

    NASA Astrophysics Data System (ADS)

    Krüger, Harald; Seidensticker, Klaus J.; Fischer, Hans-Herbert; Albin, Thomas; Apathy, Istvan; Arnold, Walter; Flandes, Alberto; Hirn, Attila; Kobayashi, Masanori; Loose, Alexander; Péter, Attila; Podolak, Morris

    2015-11-01

    Context. The Rosetta lander Philae successfully landed on the nucleus of comet 67P/Churyumov-Gerasimenko on 12 November 2014. Philae carries the Dust Impact Monitor (DIM) on board, which is part of the Surface Electric Sounding and Acoustic Monitoring Experiment (SESAME). DIM employs piezoelectric PZT sensors to detect impacts by submillimeter- and millimeter-sized ice and dust particles that are emitted from the nucleus and transported into the cometary coma. Aims: The DIM sensor measures dynamical data such as flux and the directionality of the impacting particles. Mass and speed of the particles can be constrained assuming density and elastic particle properties. Methods: DIM was operated during three mission phases of Philae at the comet: (1) before the separation of Philae from Rosetta at distances of about 9.6 km, 11.8 km, and 25.3 km from the nucleus barycenter. In this mission phase particles released from the nucleus on radial trajectories remained undetectable because of significant obscuration by the structures of Rosetta, and no dust particles were indeed detected; (2) during Philae's descent to its nominal landing site Agilkia, DIM detected one approximately millimeter-sized particle at a distance of 5.0 km from the nucleus' barycenter, corresponding to an altitude of 2.4 km from the surface. This is the closest ever dust detection at a cometary nucleus by a dedicated in situ dust detector; and (3) at Philae's final landing site, Abydos, DIM detected no dust impact which may be due to low cometary activity in the vicinity of Philae or due to shading by obstacles close to Philae, or both. Results: Laboratory calibration experiments showed that the material properties of the detected particle are compatible with a porous particle having a bulk density of approximately 250 kg m-3. The particle could have been lifted off the comet's surface by sublimating water ice.

  6. Dimming curve based on the detectability and acceptability of illuminance differences.

    PubMed

    Hu, Wenye; Davis, Wendy

    2016-05-16

    In a psychophysical forced-choice experiment, observers' ability to detect illuminance differences was found to be 7.4% of the initial illuminance. When matching the illuminance of one space with another, observers' acceptance of illuminance differences was 17.8% to 19.1%. Lighting control systems with resolutions between 14.8% and 17.7% were found to have greater usability than others. A new approach to step-dimming leverages knowledge of the detectability and acceptability of illuminance differences, as well as usability, to reduce lighting energy consumption. This method can reduce lighting energy consumption more than continuous dimming. PMID:27409961

  7. From dimming to brightening: decadal changes in solar radiation at Earth's surface.

    PubMed

    Wild, Martin; Gilgen, Hans; Roesch, Andreas; Ohmura, Atsumu; Long, Charles N; Dutton, Ellsworth G; Forgan, Bruce; Kallis, Ain; Russak, Viivi; Tsvetkov, Anatoly

    2005-05-01

    Variations in solar radiation incident at Earth's surface profoundly affect the human and terrestrial environment. A decline in solar radiation at land surfaces has become apparent in many observational records up to 1990, a phenomenon known as global dimming. Newly available surface observations from 1990 to the present, primarily from the Northern Hemisphere, show that the dimming did not persist into the 1990s. Instead, a widespread brightening has been observed since the late 1980s. This reversal is reconcilable with changes in cloudiness and atmospheric transmission and may substantially affect surface climate, the hydrological cycle, glaciers, and ecosystems. PMID:15879214

  8. Dimming curve based on the detectability and acceptability of illuminance differences.

    PubMed

    Hu, Wenye; Davis, Wendy

    2016-05-16

    In a psychophysical forced-choice experiment, observers' ability to detect illuminance differences was found to be 7.4% of the initial illuminance. When matching the illuminance of one space with another, observers' acceptance of illuminance differences was 17.8% to 19.1%. Lighting control systems with resolutions between 14.8% and 17.7% were found to have greater usability than others. A new approach to step-dimming leverages knowledge of the detectability and acceptability of illuminance differences, as well as usability, to reduce lighting energy consumption. This method can reduce lighting energy consumption more than continuous dimming.

  9. From Dimming to Brightening: Decadal Changes in Solar Radiation at Earth's Surface

    SciTech Connect

    Wild, Martin F.; Gilgen, Hans; Roesch, Andreas; Ohmura, Atsumu; Long, Charles N.; Dutton, Ellsworth G.; Forgan, B. W.; Kallis, A.; Russak, V.; Tsvetkov, Anatoly

    2005-05-06

    Variations in solar radiation incident at Earth's surface profoundly affect the human and terrestrial environment. A decline in solar radiation at land surfaces has become apparent in many observational records up to 1990, a phenomenon known as global dimming. Newly available surface observations from 1990 to the present, primarily from the Northern Hemisphere, show that the dimming did not persist into the 1990s. Instead, a widespread brightening has been observed since the late 1980s. This reversal is reconcilable with changes in cloudiness and atmospheric transmission and may substantially affect surface climate, the hydrological cycle, glaciers, and ecosystems.

  10. Analysis of energy saving ability in dimming VLC systems using LEDs with optimized SAHP

    NASA Astrophysics Data System (ADS)

    Li, Fang; Wu, Kan; Zou, Weiwen; Chen, Jianping

    2016-02-01

    In this paper, we investigate the energy saving capability of dimming visible light communication (VLC) systems employing SC-4 PPM modulation scheme. We design different optimizations to maximize the energy efficiency according to the different illuminance efficiency with respect to LED's semi-angle at half power (SAHP) for four different LED alignments. Tradeoff between energy efficiency and signal-to-noise ratio (SNR) uniformity are also investigated to achieve better overall performance. The results show that more than 40% energy can be saved over the existing dimmed VLC system employing SC-4 PPM modulation scheme when optimized SAHP LEDs are used.

  11. Features and causes of recent surface solar radiation dimming and brightening patterns

    NASA Astrophysics Data System (ADS)

    Hatzianastassiou, N.; Papadimas, C. D.; Matsoukas, C.; Pavlakis, K.; Fotiadi, A.; Wild, M.; Vardavas, I.

    2012-04-01

    Incoming solar radiation at the Earth's surface has undergone substantial decreases/increases on decadal timescales in the second half of 20th century. More specifically, surface measurements have indicated a widespread decrease of surface solar radiation (SSR) from the 1950s to the 1980s, described as global dimming, followed by a period with either no more decrease or even an increase at various locations worldwide till the end of 1990s, namely a global brightening. These measured patterns of SSR are, in general, in line with SSR fluxes computed with radiative transfer models (RTMs) using satellite input data, while efforts are currently being made to reproduce them with regional or global climate models. The advantage of reproducing SSR dimming/brightening with RTMs is that an almost complete coverage of the globe is possible, whereas dimming/brightening patterns are obtained under both clear- and all-sky conditions. Moreover, an even more important and incomparable advantage of the use of RTMs for reproducing SSR dimming/brightening, is that it makes possible the identification of their causes in terms of specific radiative forcing agents, and the assessment and quantification of their relative contribution to GDB, which is of major importance for understanding current and future climate changes. In the present study, first an update of SSR dimming/brightening at global scale beyond 2000 is attempted using a spectral RTM along with a variety of satellite and reanalyses input data. The results are obtained at scales varying from the regional to continental/hemispherical/global, and are validated through comparisons against quality surface measurements from reference global networks such as GEBA (Global Energy Balance Archive) and BSRN (Baseline Surface Radiation Network). An inter-hemispherical difference is revealed up to 2007, consisting in a clear dimming in the South Hemisphere (SH), against a no clear dimming/brightening signal in North Hemisphere (NH

  12. Experimental investigation of analog and digital dimming techniques on photometric performance of an indoor Visible Light Communication (VLC) system

    NASA Astrophysics Data System (ADS)

    Zafar, Fahad; Kalavally, Vineetha; Bakaul, Masuduzzaman; Parthiban, R.

    2015-09-01

    For making commercial implementation of light emitting diode (LED) based visible light communication (VLC) systems feasible, it is necessary to incorporate it with dimming schemes which will provide energy savings, moods and increase the aesthetic value of the places using this technology. There are two general methods which are used to dim LEDs commonly categorized as analog and digital dimming. Incorporating fast data transmission with these techniques is a key challenge in VLC. In this paper, digital and analog dimming for a 10 Mb/s non return to zero on-off keying (NRZ-OOK) based VLC system is experimentally investigated considering both photometric and communicative parameters. A spectrophotometer was used for photometric analysis and a line of sight (LOS) configuration in the presence of ambient light was used for analyzing communication parameters. Based on the experimental results, it was determined that digital dimming scheme is preferable for use in indoor VLC systems requiring high dimming precision and data transmission at lower brightness levels. On the other hand, analog dimming scheme is a cost effective solution for high speed systems where dimming precision is insignificant.

  13. Histone H3 Lysine 9 Methyltransferase DIM5 Is Required for the Development and Virulence of Botrytis cinerea

    PubMed Central

    Zhang, Xiaoli; Liu, Xinqiang; Zhao, Yanli; Cheng, Jiasen; Xie, Jiatao; Fu, Yanping; Jiang, Daohong; Chen, Tao

    2016-01-01

    Histone methylation is widely present in animals, plants and fungi, and the methylation modification of histone H3 has important biological functions. Methylation of Lys9 of histone H3 (H3K9) has been proven to regulate chromatin structure, gene silencing, transcriptional activation, plant metabolism, and other processes. In this work, we investigated the functions of a H3K9 methyltransferase gene BcDIM5 in Botrytis cinerea, which contains a PreSET domain, a SET domain and a PostSET domain. Characterization of BcDIM5 knockout transformants showed that the hyphal growth rate and production of conidiophores and sclerotia were significantly reduced, while complementary transformation of BcDIM5 could restore the phenotypes to the levels of wild type. Pathogenicity assays revealed that BcDIM5 was essential for full virulence of B. cinerea. BcDIM5 knockout transformants exhibited decreased virulence, down-regulated expression of some pathogenic genes and drastically decreased H3K9 trimethylation level. However, knockout transformants of other two genes heterochromatin protein 1 (HP1) BcHP1 and DNA methyltransferase (DIM2) BcDIM2 did not exhibit significant change in the growth phenotype and virulence compared with the wild type. Our results indicate that H3K9 methyltransferase BcDIM5 is required for H3K9 trimethylation to regulate the development and virulence of B. cinerea.

  14. Histone H3 Lysine 9 Methyltransferase DIM5 Is Required for the Development and Virulence of Botrytis cinerea.

    PubMed

    Zhang, Xiaoli; Liu, Xinqiang; Zhao, Yanli; Cheng, Jiasen; Xie, Jiatao; Fu, Yanping; Jiang, Daohong; Chen, Tao

    2016-01-01

    Histone methylation is widely present in animals, plants and fungi, and the methylation modification of histone H3 has important biological functions. Methylation of Lys9 of histone H3 (H3K9) has been proven to regulate chromatin structure, gene silencing, transcriptional activation, plant metabolism, and other processes. In this work, we investigated the functions of a H3K9 methyltransferase gene BcDIM5 in Botrytis cinerea, which contains a PreSET domain, a SET domain and a PostSET domain. Characterization of BcDIM5 knockout transformants showed that the hyphal growth rate and production of conidiophores and sclerotia were significantly reduced, while complementary transformation of BcDIM5 could restore the phenotypes to the levels of wild type. Pathogenicity assays revealed that BcDIM5 was essential for full virulence of B. cinerea. BcDIM5 knockout transformants exhibited decreased virulence, down-regulated expression of some pathogenic genes and drastically decreased H3K9 trimethylation level. However, knockout transformants of other two genes heterochromatin protein 1 (HP1) BcHP1 and DNA methyltransferase (DIM2) BcDIM2 did not exhibit significant change in the growth phenotype and virulence compared with the wild type. Our results indicate that H3K9 methyltransferase BcDIM5 is required for H3K9 trimethylation to regulate the development and virulence of B. cinerea. PMID:27597848

  15. Histone H3 Lysine 9 Methyltransferase DIM5 Is Required for the Development and Virulence of Botrytis cinerea

    PubMed Central

    Zhang, Xiaoli; Liu, Xinqiang; Zhao, Yanli; Cheng, Jiasen; Xie, Jiatao; Fu, Yanping; Jiang, Daohong; Chen, Tao

    2016-01-01

    Histone methylation is widely present in animals, plants and fungi, and the methylation modification of histone H3 has important biological functions. Methylation of Lys9 of histone H3 (H3K9) has been proven to regulate chromatin structure, gene silencing, transcriptional activation, plant metabolism, and other processes. In this work, we investigated the functions of a H3K9 methyltransferase gene BcDIM5 in Botrytis cinerea, which contains a PreSET domain, a SET domain and a PostSET domain. Characterization of BcDIM5 knockout transformants showed that the hyphal growth rate and production of conidiophores and sclerotia were significantly reduced, while complementary transformation of BcDIM5 could restore the phenotypes to the levels of wild type. Pathogenicity assays revealed that BcDIM5 was essential for full virulence of B. cinerea. BcDIM5 knockout transformants exhibited decreased virulence, down-regulated expression of some pathogenic genes and drastically decreased H3K9 trimethylation level. However, knockout transformants of other two genes heterochromatin protein 1 (HP1) BcHP1 and DNA methyltransferase (DIM2) BcDIM2 did not exhibit significant change in the growth phenotype and virulence compared with the wild type. Our results indicate that H3K9 methyltransferase BcDIM5 is required for H3K9 trimethylation to regulate the development and virulence of B. cinerea. PMID:27597848

  16. Dim nocturnal illumination alters coupling of circadian pacemakers in Siberian hamsters, Phodopus sungorus.

    PubMed

    Gorman, M R; Elliott, J A

    2004-08-01

    The circadian pacemaker of mammals comprises multiple oscillators that may adopt different phase relationships to determine properties of the coupled system. The effect of nocturnal illumination comparable to dim moonlight was assessed in male Siberian hamsters exposed to two re-entrainment paradigms believed to require changes in the phase relationship of underlying component oscillators. In experiment 1, hamsters were exposed to a 24-h light-dark-light-dark cycle previously shown to split circadian rhythms into two components such that activity is divided between the two daily dark periods. Hamsters exposed to dim illumination (<0.020 lx) during each scotophase were more likely to exhibit split rhythms compared to hamsters exposed to completely dark scotophases. In experiment 2, hamsters were transferred to winter photoperiods (10 h light, 14 h dark) from two different longer daylengths (14 h or 18 h light daily) in the presence or absence of dim nighttime lighting. Dim nocturnal illumination markedly accelerated adoption of the winter phenotype as reflected in the expansion of activity duration, gonadal regression and weight loss. The two experiments demonstrate substantial efficacy of light intensities generally viewed as below the threshold of circadian systems. Light may act on oscillator coupling through rod-dependent mechanisms.

  17. Dim moving target tracking algorithm based on particle discriminative sparse representation

    NASA Astrophysics Data System (ADS)

    Li, Zhengzhou; Li, Jianing; Ge, Fengzeng; Shao, Wanxing; Liu, Bing; Jin, Gang

    2016-03-01

    The small dim moving target usually submerged in strong noise, and its motion observability is debased by numerous false alarms for low signal-to-noise ratio (SNR). A target tracking algorithm based on particle filter and discriminative sparse representation is proposed in this paper to cope with the uncertainty of dim moving target tracking. The weight of every particle is the crucial factor to ensuring the accuracy of dim target tracking for particle filter (PF) that can achieve excellent performance even under the situation of non-linear and non-Gaussian motion. In discriminative over-complete dictionary constructed according to image sequence, the target dictionary describes target signal and the background dictionary embeds background clutter. The difference between target particle and background particle is enhanced to a great extent, and the weight of every particle is then measured by means of the residual after reconstruction using the prescribed number of target atoms and their corresponding coefficients. The movement state of dim moving target is then estimated and finally tracked by these weighted particles. Meanwhile, the subspace of over-complete dictionary is updated online by the stochastic estimation algorithm. Some experiments are induced and the experimental results show the proposed algorithm could improve the performance of moving target tracking by enhancing the consistency between the posteriori probability distribution and the moving target state.

  18. AN AUTOMATIC DETECTION METHOD FOR EXTREME-ULTRAVIOLET DIMMINGS ASSOCIATED WITH SMALL-SCALE ERUPTION

    SciTech Connect

    Alipour, N.; Safari, H.; Innes, D. E.

    2012-02-10

    Small-scale extreme-ultraviolet (EUV) dimming often surrounds sites of energy release in the quiet Sun. This paper describes a method for the automatic detection of these small-scale EUV dimmings using a feature-based classifier. The method is demonstrated using sequences of 171 Angstrom-Sign images taken by the STEREO/Extreme UltraViolet Imager (EUVI) on 2007 June 13 and by Solar Dynamics Observatory/Atmospheric Imaging Assembly on 2010 August 27. The feature identification relies on recognizing structure in sequences of space-time 171 Angstrom-Sign images using the Zernike moments of the images. The Zernike moments space-time slices with events and non-events are distinctive enough to be separated using a support vector machine (SVM) classifier. The SVM is trained using 150 events and 700 non-event space-time slices. We find a total of 1217 events in the EUVI images and 2064 events in the AIA images on the days studied. Most of the events are found between latitudes -35 Degree-Sign and +35 Degree-Sign . The sizes and expansion speeds of central dimming regions are extracted using a region grow algorithm. The histograms of the sizes in both EUVI and AIA follow a steep power law with slope of about -5. The AIA slope extends to smaller sizes before turning over. The mean velocity of 1325 dimming regions seen by AIA is found to be about 14 km s{sup -1}.

  19. A Valuable Experience for Children: The Dim Sum and Chinese Restaurant Project

    ERIC Educational Resources Information Center

    Ha, Yuen Lai

    2010-01-01

    This article describes the Dim Sum and Chinese Restaurant Project undertaken by 6-year-old kindergarten children in Hong Kong. The article discusses the importance of listening, observing, and documenting children's actions to meet their needs and interests. The kindergarten program that participated in this project is a nonprofit kindergarten…

  20. Detection of solar dimming and brightening effects on Northern Hemisphere river flow

    NASA Astrophysics Data System (ADS)

    Gedney, N.; Huntingford, C.; Weedon, G. P.; Bellouin, N.; Boucher, O.; Cox, P. M.

    2014-11-01

    Anthropogenic aerosols in the atmosphere have the potential to affect regional-scale land hydrology through solar dimming. Increased aerosol loading may have reduced historical surface evaporation over some locations, but the magnitude and extent of this effect is uncertain. Any reduction in evaporation due to historical solar dimming may have resulted in an increase in river flow. Here we formally detect and quantify the historical effect of changing aerosol concentrations, via solar radiation, on observed river flow over the heavily industrialized, northern extra-tropics. We use a state-of-the-art estimate of twentieth century surface meteorology as input data for a detailed land surface model, and show that the simulations capture the observed strong inter-annual variability in runoff in response to climatic fluctuations. Using statistical techniques, we identify a detectable aerosol signal in the observed river flow both over the combined region, and over individual river basins in Europe and North America. We estimate that solar dimming due to rising aerosol concentrations in the atmosphere around 1980 led to an increase in river runoff by up to 25% in the most heavily polluted regions in Europe. We propose that, conversely, these regions may experience reduced freshwater availability in the future, as air quality improvements are set to lower aerosol loading and solar dimming.

  1. Attenuation of multi-targeted proliferation-linked signaling by 3,3'-diindolylmethane (DIM): from bench to clinic.

    PubMed

    Banerjee, Sanjeev; Kong, Dejuan; Wang, Zhiwei; Bao, Bin; Hillman, Gilda G; Sarkar, Fazlul H

    2011-01-01

    Emerging evidence provide credible support in favor of the potential role of bioactive products derived from ingesting cruciferous vegetables such as broccoli, brussel sprouts, cauliflower and cabbage. Among many compounds, 3,3'-diindolylmethane (DIM) is generated in the acidic environment of the stomach following dimerization of indole-3-carbinol (I3C) monomers present in these classes of vegetables. Both I3C and DIM have been investigated for their use in preventing, inhibiting, and reversing the progression of cancer - as a chemopreventive agent. In this review, we summarize an updated, wide-ranging pleiotropic anti-tumor and biological effects elicited by DIM against tumor cells. It is unfeasible to point one single target as basis of cellular target of action of DIM. We emphasize key cellular and molecular events that are effectively modulated in the direction of inducing apoptosis and suppressing cell proliferation. Collectively, DIM orchestrates signaling through Ah receptor, NF-κB/Wnt/Akt/mTOR pathways impinging on cell cycle arrest, modulation of key cytochrome P450 enzymes, altering angiogenesis, invasion, metastasis and epigenetic behavior of cancer cells. The ability of DIM to selectively induce tumor cells to undergo apoptosis has been observed in preclinical models, and thus it has been speculated in improving the therapeutic efficacy of other anticancer agents that have diverse molecular targets. Consequently, DIM has moved through preclinical development into Phase I clinical trials, thereby suggesting that DIM could be a promising and novel agent either alone or as an adjunct to conventional therapeutics such as chemo-radio and targeted therapies. An important development has been the availability of DIM formulation with superior bioavailability for humans. Therefore, DIM appears to be a promising chemopreventive agent or chemo-radio-sensitizer for the prevention of tumor recurrence and/or for the treatment of human malignancies.

  2. ONE-DIMENSIONAL MODELING FOR TEMPERATURE-DEPENDENT UPFLOW IN THE DIMMING REGION OBSERVED BY HINODE/EUV IMAGING SPECTROMETER

    SciTech Connect

    Imada, S.; Shimizu, T.; Hara, H.; Watanabe, T.; Murakami, I.; Harra, L. K.; Zweibel, E. G.

    2011-12-10

    We previously found a temperature-dependent upflow in the dimming region following a coronal mass ejection observed by the Hinode EUV Imaging Spectrometer (EIS). In this paper, we reanalyzed the observations along with previous work on this event and provided boundary conditions for modeling. We found that the intensity in the dimming region dramatically drops within 30 minutes from the flare onset, and the dimming region reaches the equilibrium stage after {approx}1 hr. The temperature-dependent upflows were observed during the equilibrium stage by EIS. The cross-sectional area of the flux tube in the dimming region does not appear to expand significantly. From the observational constraints, we reconstructed the temperature-dependent upflow by using a new method that considers the mass and momentum conservation law and demonstrated the height variation of plasma conditions in the dimming region. We found that a super-radial expansion of the cross-sectional area is required to satisfy the mass conservation and momentum equations. There is a steep temperature and velocity gradient of around 7 Mm from the solar surface. This result may suggest that the strong heating occurred above 7 Mm from the solar surface in the dimming region. We also showed that the ionization equilibrium assumption in the dimming region is violated, especially in the higher temperature range.

  3. Dim scotopic illumination accelerates the reentrainment following simulated jetlags in a diurnal experimental model, Drosophila

    PubMed Central

    Sinam, Boynao; Sharma, Shweta; Thakurdas, Pooja; Kasture, Madhukar; Shivagaje, Ashok; Joshi, Dilip

    2013-01-01

    Jetlag results from the misalignment between the endogenous circadian timing and the civil timing after a transmeridian flight. Efficacy of the dim nocturnal illumination (0.03 lx) in accelerating the reentrainment following simulated jetlags in Drosophila biarmipes was examined by subjecting the flies to 24 h light-dark cycles in which the 12 h photophase was at 300 lx for all flies but the scotophase was at 0 and 0.03 lx for the control and experimental flies, respectively. Reentrainment was always faster in the experimental flies than the control ones. Moreover, unlike melatonin, the dimly lit nights accelerated the reentrainment following both, the phase advance and delay of the light-dark cycles. This study might have potential application as a non-drug jetlag treatment. PMID:23802034

  4. Gross spectral differences between bright and dim gamma-ray bursts

    NASA Technical Reports Server (NTRS)

    Nemiroff, R. J.; Norris, J. P.; Bonnell, J. T.; Wickramasinghe, W. A. D. T.; Kouveliotou, C.; Paciesas, W. S.; Fishman, G. J.; Meegan, C. A.

    1994-01-01

    We find that dim gamma-ray bursts (GRBs) are softer than bright GRBs, as indicated on average by data from the Burst and Transient Source Experiment (BATSE) on board the Compton Gamma Ray Observatory (CGRO). We show that this correlation is statistically significant with respect to variations due to random differences between GRBs. This effect is discernible using a variety of methods and data sets, including public domain data. We analyze several types of systematic errors and selection effects in the BATSE data and conclude that the observed effect is not dominated by any of them. We therefore assert that this dim/soft effect is a real property of GRBs. It is possible that this correlation is a consequence of the time dilation and that the burst sources are located at cosmological distances.

  5. Photon-axion conversion as a mechanism for supernova dimming: Limits from CMB spectral distortion

    SciTech Connect

    Mirizzi, Alessandro; Raffelt, Georg G.; Serpico, Pasquale D.

    2005-07-15

    Axion-photon conversion induced by intergalactic magnetic fields has been proposed as an explanation for the dimming of distant supernovae of type Ia (SNe Ia) without cosmic acceleration. The effect depends on the intergalactic electron density n{sub e} as well as the B-field strength and domain size. We show that for n{sub e} < or approx. 10{sup -9} cm{sup -3} the same mechanism would cause excessive spectral distortion of the cosmic microwave background (CMB). This small-n{sub e} parameter region had been left open by the most restrictive previous constraints based on the dispersion of quasar (QSO) spectra. The combination of CMB and QSO limits suggests that the photon-axion conversion mechanism can only play a subleading role for SN Ia dimming. A combined analysis of all the observables affected by the photon-axion oscillations would be required to give a final verdict on the viability of this model.

  6. Dimming LEDs with Phase-Cut Dimmers: The Specifier's Process for Maximizing Success

    SciTech Connect

    Miller, Naomi J.; Poplawski, Michael E.

    2013-10-01

    This report reviews how phase-cut dimmers work, how LEDs differ from the incandescent lamps that the dimmers were historically designed to control, and how these differences can lead to complications when trying to dim LEDs. Compatibility between a specific LED source and a specific phase-cut dimmer is often unknown and difficult to assess, and ensuring compatibility adds complexity to the design, specification, bidding, and construction observation phases for new buildings and major remodel projects. To maximize project success, this report provides both general guidance and step-by-step procedures for designing phase-controlled LED dimming on both new and existing projects, as well as real-world examples of how to use those procedures.

  7. Direct effect of aerosol optical properties on global dimming and brightening

    NASA Astrophysics Data System (ADS)

    Kudo, R.; Uchiyama, A.

    2011-12-01

    Surface solar radiation observed at numerous locations has decreased from the 1960s to the 1980s (Global dimming), thereafter increased (Global brightening). The dimming and brightening is considered to be due to the changes in both clouds and aerosols. Aerosols have a direct impact on the surface solar radiation by scattering and absorption. The impact is determined by three parameters: optical depth (AOD), single scattering albedo (SSA), and asymmetry factor, but the effect of asymmetry factor is rather smaller than the others. Therefore, the long-term changes in AOD and SSA are necessary to evaluate the aerosol impact on the global dimming and brightening. We have developed the method to estimate AOD and SSA from the hourly accumulated direct and diffuse irradiances measured by the ground-based broadband radiometers. In the estimation, the real part of the refractive index is fixed, and the size distribution is defined by the Junge distribution with a fixed shaping constant. Using the developed method, the measurements from 1975 to 2008 at 14 sites in Japan were analyzed. Consequently, a decrease of AOD by 0.02 and an increase of SSA by 0.2 during the period were seen. The surface solar radiation under the clear sky conditions, which was calculated from the estimated aerosol optical properties, was increased by 5% due to the changes in AOD and SSA; the influence of SSA was dominant. We also investigate the cloud impact on the surface solar radiation which was simply defined as the difference between the surface solar radiation under the cloudy sky conditions and under the clear sky conditions; the cloud impact had no statistically significant trends. The brightening in Japan may be due to the changes in aerosol optical properties, especially SSA. Our developed method can be applied to measurements at other sites around the world and would be helpful to understand the causes of the global dimming and brightening.

  8. Dim light at night disrupts molecular circadian rhythms and increases body weight.

    PubMed

    Fonken, Laura K; Aubrecht, Taryn G; Meléndez-Fernández, O Hecmarie; Weil, Zachary M; Nelson, Randy J

    2013-08-01

    With the exception of high latitudes, life has evolved under bright days and dark nights. Most organisms have developed endogenously driven circadian rhythms that are synchronized to this daily light/dark cycle. In recent years, humans have shifted away from the naturally occurring solar light cycle in favor of artificial and sometimes irregular light schedules produced by electric lighting. Exposure to unnatural light cycles is increasingly associated with obesity and metabolic syndrome; however, the means by which environmental lighting alters metabolism are poorly understood. Thus, we exposed mice to dim light at night and investigated changes in the circadian system and metabolism. Here we report that exposure to ecologically relevant levels of dim (5 lux) light at night altered core circadian clock rhythms in the hypothalamus at both the gene and protein level. Circadian rhythms in clock expression persisted during light at night; however, the amplitude of Per1 and Per2 rhythms was attenuated in the hypothalamus. Circadian oscillations were also altered in peripheral tissues critical for metabolic regulation. Exposure to dimly illuminated, as compared to dark, nights decreased the rhythmic expression in all but one of the core circadian clock genes assessed in the liver. Additionally, mice exposed to dim light at night attenuated Rev-Erb expression in the liver and adipose tissue. Changes in the circadian clock were associated with temporal alterations in feeding behavior and increased weight gain. These results are significant because they provide evidence that mild changes in environmental lighting can alter circadian and metabolic function. Detailed analysis of temporal changes induced by nighttime light exposure may provide insight into the onset and progression of obesity and metabolic syndrome, as well as other disorders involving sleep and circadian rhythm disruption.

  9. Exploring optically dark and dim gamma-ray bursts: Instrumentation observation and analysis

    NASA Astrophysics Data System (ADS)

    Nysewander, Melissa C.

    2006-06-01

    For the past decade, after the first afterglows of gamma-ray bursts (GRBs) were observed, astronomers have puzzled over the question of why some bursts have bright optical afterglows, while others have no detected emission at all, despite quick, deep searches. The source of the darkness can reveal specific clues to the nature of the progenitor and its local environment, or hint at global information pertaining to star-formation rates or the early universe itself, for example. Astronomers have identified possible causes of dark afterglows: (1) the burst lies at high redshift, (2) the burst is extinguished by dust in the host galaxy, (3) the burst occurred in a low-density region, or (4) the intrinsic light from the burst is dim due to microphysical parameters of the shock. We present a two-pronged approach to understand the nature of dark and dim bursts. First, we detail the results of a large observing campaign designed to seek out and observe the optical and near-infrared afterglows of gamma-ray bursts in order to establish which are dark or dim. Secondly, we present PROMPT (Panchromatic Robotic Optical Monitoring and Polarimetry Telescopes), whose unique design allows it to identify afterglows that are highly reddened due to redshift and dust. PROMPT responds automatically to satellite notification, only tens of seconds after a GRB occurs, and can observe afterglows when they are at their brightest to discover dim afterglows that may have been missed with observations at later time. As proof of concept, I present a first look at the success of PROMPT's first year of operations and the eight rapid-time responses it made.

  10. Effects of Solar Dimming and Brightening on the Terrestrial Carbon Sink

    NASA Astrophysics Data System (ADS)

    Mercado, L. M.; Bellouin, N.; Sitch, S.; Boucher, O.; Huntingford, C.; Cox, P. M.

    2008-12-01

    A decrease in total solar radiation (Liepert, 2002, Stanhill and Cohen, 2001, Wild et al., 2005) has been observed at the earth surface over the 1950-1990 period, called solar dimming. Such dimming gradually started to transform into brightening in some regions of the world since the late 1980s (Wild et al. 2005). Both dimming and brightening are likely to be linked to an increase and decrease in cloud cover and scattering and absorption of light by tropospheric and stratospheric aerosols respectively (Kvalevag and Myhre, 2007). Theoretical and observational studies have shown that plant photosynthesis of forest and crop ecosystems is more efficient under diffuse light conditions (Gu et al., 2003, Niyogi et al., 2004, Oliveira et al., 2007, Roderick et al., 2001). However, this effect has not yet been accounted for in global carbon cycle simulations because such models lack the mechanism that includes the diffuse irradiance effects on photosynthesis. The aim of this study is to estimate the impact of changes in radiation during the 1900-2100 period on land productivity and carbon storage. We use an offline version of the land surface scheme of the Hadley centre model (Mercado et al., 2007) which has been modified to account for variations of direct and diffuse radiation on sunlit and shaded canopy photosynthesis. Additionally, we use short wave and photosynthetic active radiation fields reconstructed from the Hadley centre climate model which takes into account the scattering and absorption of light by tropospheric and stratospheric aerosols. We describe the simulation of the land carbon cycle through the dimming-brightening periods, and diagnose the impact that changes in diffuse radiation had on the land carbon sink. We also discuss the implications of these results for the future land carbon-sink, under likely changes in the atmospheric aerosol loading.

  11. Aerosol emissions and dimming/brightening in Europe: Sensitivity studies with ECHAM5-HAM

    NASA Astrophysics Data System (ADS)

    Folini, D.; Wild, M.

    2011-11-01

    Observational data indicate a decrease of surface solar radiation (SSR) in Europe from about 1950 to the mid-1980s, followed by a renewed increase. Changing aerosol emissions have been suggested as a likely cause for this observed dimming and brightening. To quantify this hypothesis, we performed ensembles of transient sensitivity experiments with the global climate model ECHAM5-HAM, which includes interactive treatment of aerosols. The simulations cover the period 1950-2005 and use transient aerosol emissions (National Institute of Environmental Science, Japan) and prescribed sea surface temperatures (SSTs) from the Hadley Centre. The simulated clear-sky dimming and brightening can be attributed to changing aerosol emissions from fossil fuel combustion. Ensemble means of modeled SSR trends are in agreement with observed values. Dimming ceases too early in the model, around 1970. Potential causes are discussed. Brightening sets in at about the right time. Regional differences of modeled SSR are substantial, with clear-sky dimming trends ranging from -6.1 (eastern Europe) to -0.4 W m-2 decade-1 (British Isles) and brightening trends ranging from +1.3 to +6.3 W m-2 decade-1 (Scandinavia and eastern Europe). All-sky conditions show similar trends in the ensemble mean, but the spread among ensemble members is considerable, emphasizing the importance of clouds. Surface temperatures are found to depend mostly on the prescribed SSTs, with an additional aerosol component in some regions like eastern Europe. For precipitation, internal variability is too large to allow for any firm conclusions.

  12. A lightning-based search for nearby observationally dim terrestrial gamma ray flashes

    NASA Astrophysics Data System (ADS)

    McTague, L. E.; Cummer, S. A.; Briggs, M. S.; Connaughton, V.; Stanbro, M.; Fitzpatrick, G.

    2015-12-01

    Current space-based observations of terrestrial gamma ray flashes (TGFs) are capable of identifying only TGFs that exceed a lower brightness threshold. Observationally, dim TGFs that fall below this threshold are consequently difficult to find using photon-only search algorithms. Such TGFs are a potentially important part of the overall global TGF rate, and information on their occurrence rate would give important insight into TGF generation mechanisms. We describe and implement a lightning-based search for TGFs that uses the location and time of National Lightning Detection Network reported positive polarity, in-cloud (+IC) discharges of the type known to be directly associated with TGFs. These events identify a 200 μs search window when any associated TGF photons would have been detected. We show that this approach can detect TGFs without requiring a lower threshold on the detected photon brightness of the event, and thus is capable, in principle, of finding a population of weak TGFs. We find that TGFs occur at a rate between 1 in 40 and 1 in 500 of in-cloud lightning events that meet our study's criteria. The distribution of gamma ray counts in the search windows exhibits a statistically significant lack of nearby dim TGFs below the GBM search threshold. The data favor a brightness distribution in which nearby observationally dim TGFs are rare.

  13. Solar Demon - an approach to detecting flares, dimmings, and EUV waves on SDO/AIA images

    NASA Astrophysics Data System (ADS)

    Kraaikamp, Emil; Verbeeck, Cis

    2015-06-01

    Flares, dimmings, and extreme ultraviolet (EUV) waves are three types of eruptive phenomena on the Sun, which are main drivers of space weather. Fast and reliable detection of these phenomena helps augment space weather predictions. In the current paper, we introduce Solar Demon, the first software that detects all three phenomena, using a modular design to exploit synergies. While Solar Demon runs in near real-time on SDO/AIA synoptic quick-look images to provide fast detections of flares, dimmings, and EUV waves for space weather purposes, it also processes new Atmospheric Imaging Assembly (AIA) synoptic science images on a regular basis to build dedicated science quality catalogs. An overview of Solar Demon is given, with a focus on the algorithms for EUV wave detection and characterization. Several first results, such as flare and dimming butterfly diagrams for the rising part of Solar Cycle 24, are presented. The main advantages, challenges, and future prospects for Solar Demon are outlined in the Section 5.

  14. Duration distributions of bright and dim BATSE gamma-ray bursts

    NASA Technical Reports Server (NTRS)

    Norris, J. P.; Bonnell, J. T.; Nemiroff, R. J.; Scargle, J. D.; Kouveliotou, C.; Paciesas, W. S.; Meegan, C. A.; Fishman, G. J.

    1995-01-01

    We have measured the T(sub 90) and T(sub 50) durations of bright and dim gamma-ray bursts detected by the Compton Gamma-Ray Observatory's (CGRO) Burst and Transient Source Experiment (BASTE). The T(sub 90) T(sub 50) duration is defined as the interval over which 5% (25%) to 95% (75%) of the burst counts accumulate. Out of 775 bursts observed by BATSE 159 bursts were analyzed; bursts with durations shorter than 1.5 s were excluded. A Kolmogorov-Smirnov test yields a probability of 6 x 10(exp -5) that the T(sub 50) durations of the dim and bright samples are drawn from the same parent population. We find that the centroid and extent of the duration distribution for the dim sample are scaled by approximately a factor of 2 relative to those of the bright sample. The measured time-dilation factor is not sensitive to choice of energy band. These results are quantitatively consistent with previous tests for time dilation in a smaller sample of BATSE bursts. The sources of dimmer bursts, if cosmological, would lie at redshifts of order 2.

  15. Performance of Integrated Systems of Automated Roller Shade Systems and Daylight Responsive Dimming Systems

    SciTech Connect

    Park, Byoung-Chul; Choi, An-Seop; Jeong, Jae-Weon; Lee, Eleanor S.

    2010-07-08

    Daylight responsive dimming systems have been used in few buildings to date because they require improvements to improve reliability. The key underlying factor contributing to poor performance is the variability of the ratio of the photosensor signal to daylight workplane illuminance in accordance with sun position, sky condition, and fenestration condition. Therefore, this paper describes the integrated systems between automated roller shade systems and daylight responsive dimming systems with an improved closed-loop proportional control algorithm, and the relative performance of the integrated systems and single systems. The concept of the improved closed-loop proportional control algorithm for the integrated systems is to predict the varying correlation of photosensor signal to daylight workplane illuminance according to roller shade height and sky conditions for improvement of the system accuracy. In this study, the performance of the integrated systems with two improved closed-loop proportional control algorithms was compared with that of the current (modified) closed-loop proportional control algorithm. In the results, the average maintenance percentage and the average discrepancies of the target illuminance, as well as the average time under 90percent of target illuminance for the integrated systems significantly improved in comparison with the current closed-loop proportional control algorithm for daylight responsive dimming systems as a single system.

  16. Infrared dim small target detection algorithm based on NSCT and SVD

    NASA Astrophysics Data System (ADS)

    Zhao, Ying; Liu, Gang; Zhou, Huixin; Qin, Hanlin; Li, Xiao; Wen, Zhigang; Ni, Man; Wang, Bingjian

    2015-10-01

    A novel dim small target detection algorithm based on the nonsubsampled contourlet transform (NSCT) and the singular value decomposition (SVD) is proposed in this paper, which is to improve the performance of the dim small target detection under the complex sky cloud background. Firstly, the original infrared image is decomposed with the SVD, and several different numbers of the singular value for reconstruction is chosen to analyze the application of the SVD to the image. The complex sky cloud background in the infrared target image is predicted by choosing a certain number of the singular value to reconstruct the image, and it is subtracted from the original image to suppress the background and enhance the target signal. Secondly, to use the scale and the direction information of the image, the residual image is decomposed by the NSCT into several high-pass directional subbands and a low-pass subband. Thirdly, the SVD filtering is utilized again to those directional subbands to eliminate the noise and the residual background. And the low-pass subband is modified by the local mean removal method. Finally, the refined subbands are reconstructed by the inverse NSCT to fulfill the dim small target detection. The experimental results demonstrate that the proposed algorithm has better subjective vision and objective numerical indicators, and can acquire a better performance of the target detection.

  17. A robust infrared dim target detection method based on template filtering and saliency extraction

    NASA Astrophysics Data System (ADS)

    Wang, Wenguang; Li, Chenming; Shi, Jianing

    2015-11-01

    Dim target detection in infrared image with complex background and low signal-clutter ratio (SCR) is a significant and difficult task in the infrared target tracking system. A robust infrared dim target detection method based on template filtering and saliency extraction is proposed in this paper. The weighted gray map is obtained from the infrared image to highlight the target which is brighter than its neighbors and has weak correlation with its background. The target saliency map is then calculated by phase spectrum of Fourier Transform, so that the dim target detection could be converted to salient region extraction. The potential targets are finally extracted by combining the two maps. Moreover, position discrimination between targets in the two maps is used to exclude the false alarms and extract the targets. Experimental results on measured images indicate that our method is feasible, adaptable and robust in different backgrounds. The ROC (Receiver Operating Characteristic) curves obtained from the simulated images demonstrate the proposed method outperforms some existing typical methods in both detection rate and false alarm rate, for target detection with low SCR.

  18. Time-dependent effects of dim light at night on re-entrainment and masking of hamster activity rhythms.

    PubMed

    Frank, David W; Evans, Jennifer A; Gorman, Michael R

    2010-04-01

    Bright light has been established as the most ubiquitous environmental cue that entrains circadian timing systems under natural conditions. Light equivalent in intensity to moonlight (<1 lux), however, also strongly modulates circadian function in a number of entrainment paradigms. For example, compared to completely dark nights, dim nighttime illumination accelerated re-entrainment of hamster activity rhythms to 4-hour phase advances and delays of an otherwise standard laboratory photocycle. The purpose of this study was to determine if a sensitive period existed in the night during which dim illumination had a robust influence on speed of re-entrainment. Male Siberian hamsters were either exposed to dim light throughout the night, for half of the night, or not at all. Compared to dark nights, dim illumination throughout the entire night decreased by 29% the time for the midpoint of the active phase to re-entrain to a 4-hour phase advance and by 26% for a 4-hour delay. Acceleration of advances and delays were also achieved with 5 hours of dim light per night, but effects depended on whether dim light was present in the first half, second half, or first and last quarters of the night. Both during phase shifting and steady-state entrainment, partially lit nights also produced strong positive and negative masking effects, as well as entrainment aftereffects in constant darkness. Thus, even in the presence of a strong zeitgeber, light that might be encountered under a natural nighttime sky potently modulates the circadian timing system of hamsters.

  19. Crystal Structure of DIM-1, an Acquired Subclass B1 Metallo-β-Lactamase from Pseudomonas stutzeri

    PubMed Central

    Booth, Michael P. S.; Kosmopoulou, Magda; Poirel, Laurent; Nordmann, Patrice; Spencer, James

    2015-01-01

    Metallo-β-lactamases (MBLs) hydrolyze almost all classes of β-lactam antibiotic, including carbapenems—currently first choice drugs for opportunistic infections by Gram-negative bacterial pathogens. MBL inhibitor development is complicated by the diversity within this group of enzymes, and by the appearance of new enzymes that continue to be identified both as chromosomal genes and on mobile genetic elements. One such newly discovered MBL is DIM-1, a mobile enzyme originally discovered in the opportunist pathogen Pseudomonas stutzeri but subsequently identified in other species and locations. DIM-1 is a subclass B1 MBL more closely related to the TMB-1, GIM-1 and IMP enzymes than to other clinically encountered MBLs such as VIM and NDM; and possesses Arg, rather than the more usual Lys, at position 224 in the putative substrate binding site. Here we report the crystallization and structure determination of DIM-1. DIM-1 possesses a binuclear metal center with a 5 (rather than the more usual 4) co-ordinate tri-histidine (Zn1) site and both 4- and 5-co-ordinate Cys-His-Asp- (Zn2) sites observed in the two molecules of the crystallographic asymmetric unit. These data indicate a degree of variability in metal co-ordination geometry in the DIM-1 active site, as well as facilitating inclusion of DIM-1 in structure-based MBL inhibitor discovery programmes. PMID:26451836

  20. Lighting schedule and dimming period in early life: consequences for broiler chicken leg bone development.

    PubMed

    van der Pol, Carla W; Molenaar, Roos; Buitink, Christiaan J; van Roovert-Reijrink, Inge A M; Maatjens, Conny M; van den Brand, Henry; Kemp, Bas

    2015-12-01

    Prolonged (>20 h) light periods during grow-out of broiler chickens have been shown to increase the occurrence of skeletal abnormalities, but the effects of early life light-dark schedules are not well known. The present experiment investigated the effect of lighting schedule and light-dark transition during the first days of a broiler chicken's life on leg bone development. In 2 experiments, Ross-308 broiler chicks (n = 2,500 per experiment) were subjected to 1 of 5 treatments for 4 d: 24L; 2L:1D lighting schedule with either an abrupt or gradual light-dark transition ("dimming"); and a 2L:6D lighting schedule with an abrupt transition or dimming. At d 4, tibia and femur weight, length, and diameter, yolk free body mass, organ weights, realized weight gain, feed intake, feed conversion ratio, and mortality were determined. In Experiment 2, chick length and relative asymmetry of the femur and tibia were determined additionally. Data were analyzed using orthogonal contrasts. 24L resulted in higher femur diameter (P<0.028; both experiments), tibia diameter (P<0.001; Experiment 1), relative asymmetry of tibia length (P=0.002; Experiment 2), and relative asymmetry of femur length (P=0.003) than applying a light-dark schedule. A 2L:1D lighting schedule resulted in higher femur length (P=0.039; Experiment 1) and relative asymmetry of tibia length (P=0.032; Experiment 2) and lower relative asymmetry of tibia diameter (P=0.016) than a 2L:6D lighting schedule. An abrupt light-dark transition resulted in higher relative asymmetry of tibia length (P=0.004; Experiment 2) and relative asymmetry of tibia diameter (P=0.018) than dimming. To conclude, leg bone development in the first 4 d of a broiler chicken's life was higher for 24L than when a lighting schedule was applied, but relative asymmetry was higher as well, suggesting developmental instability. The effect of dimming on leg bone development was less pronounced, but the decreased relative asymmetry levels in the dimming

  1. Lipid-based oral delivery systems for skin deposition of a potential chemopreventive DIM derivative: characterization and evaluation.

    PubMed

    Boakye, Cedar H A; Patel, Ketan; Patel, Apurva R; Faria, Henrique A M; Zucolotto, Valtencir; Safe, Stephen; Singh, Mandip

    2016-10-01

    The objective of this study was to explore the oral route as a viable potential for the skin deposition of a novel diindolylmethane derivative (DIM-D) for chemoprevention activity. Various lipid-based oral delivery systems were optimized and compared for enhancing DIM-D's oral bioavailability and skin deposition. Preformulation studies were performed to evaluate the log P and solubility of DIM-D. Microsomal metabolism, P-glycoprotein efflux, and caco-2 monolayer permeability of DIM-D were determined. Comparative evaluation of the oral absorption and skin deposition of DIM-D-loaded various lipid-based formulations was performed in rats. DIM-D showed pH-dependent solubility and a high log P value. It was not a strong substrate of microsomal degradation and P-glycoprotein. SMEDDs comprised of medium chain triglycerides, monoglycerides, and kolliphor-HS15 (36.70 ± 0.42 nm). SNEDDs comprised of long chain triglycerides, cremophor RH40, labrasol, and TPGS (84.00 ± 14.14 nm). Nanostructured lipid carriers (NLC) consisted of compritol, miglyol, and surfactants (116.50 ± 2.12 nm). The blank formulations all showed >70 % cell viability in caco-2 cells. Differential Scanning Calorimetry confirmed the amorphization of DIM-D within the lipid matrices while Atomic Force Microscopy showed particle size distribution similar to the dynamic light scattering data. DIM-D also showed reduced permeation across caco-2 monolayer that was enhanced (p < 0.05) by SNEDDs in comparison to SMEDDs and NLC. Fabsolute for DIM-D SNEDDs, SMEDDs, and NLC was 0.14, 0.04, and 0.007, respectively. SNEDDs caused 53.90, 11.32, and 15.08-fold more skin deposition of DIM-D than the free drug, SMEDDs, and NLC, respectively, at 2 h following oral administration and shows a viable potential for use in skin cancer chemoprevention. Graphical Abstract ᅟ. PMID:27405772

  2. Lipid-based oral delivery systems for skin deposition of a potential chemopreventive DIM derivative: characterization and evaluation.

    PubMed

    Boakye, Cedar H A; Patel, Ketan; Patel, Apurva R; Faria, Henrique A M; Zucolotto, Valtencir; Safe, Stephen; Singh, Mandip

    2016-10-01

    The objective of this study was to explore the oral route as a viable potential for the skin deposition of a novel diindolylmethane derivative (DIM-D) for chemoprevention activity. Various lipid-based oral delivery systems were optimized and compared for enhancing DIM-D's oral bioavailability and skin deposition. Preformulation studies were performed to evaluate the log P and solubility of DIM-D. Microsomal metabolism, P-glycoprotein efflux, and caco-2 monolayer permeability of DIM-D were determined. Comparative evaluation of the oral absorption and skin deposition of DIM-D-loaded various lipid-based formulations was performed in rats. DIM-D showed pH-dependent solubility and a high log P value. It was not a strong substrate of microsomal degradation and P-glycoprotein. SMEDDs comprised of medium chain triglycerides, monoglycerides, and kolliphor-HS15 (36.70 ± 0.42 nm). SNEDDs comprised of long chain triglycerides, cremophor RH40, labrasol, and TPGS (84.00 ± 14.14 nm). Nanostructured lipid carriers (NLC) consisted of compritol, miglyol, and surfactants (116.50 ± 2.12 nm). The blank formulations all showed >70 % cell viability in caco-2 cells. Differential Scanning Calorimetry confirmed the amorphization of DIM-D within the lipid matrices while Atomic Force Microscopy showed particle size distribution similar to the dynamic light scattering data. DIM-D also showed reduced permeation across caco-2 monolayer that was enhanced (p < 0.05) by SNEDDs in comparison to SMEDDs and NLC. Fabsolute for DIM-D SNEDDs, SMEDDs, and NLC was 0.14, 0.04, and 0.007, respectively. SNEDDs caused 53.90, 11.32, and 15.08-fold more skin deposition of DIM-D than the free drug, SMEDDs, and NLC, respectively, at 2 h following oral administration and shows a viable potential for use in skin cancer chemoprevention. Graphical Abstract ᅟ.

  3. Exposure to dim light at night during early development increases adult anxiety-like responses.

    PubMed

    Borniger, Jeremy C; McHenry, Zachary D; Abi Salloum, Bachir A; Nelson, Randy J

    2014-06-22

    Early experiences produce effects that may persist throughout life. Therefore, to understand adult phenotype, it is important to investigate the role of early environmental stimuli in adult behavior and health. Artificial light at night (LAN) is an increasingly common phenomenon throughout the world. However, animals, including humans, evolved under dark night conditions. Many studies have revealed affective, immune, and metabolic alterations provoked by aberrant light exposure and subsequent circadian disruption. Pups are receptive to entraining cues from the mother and then light early during development, raising the possibility that the early life light environment may influence subsequent behavior. Thus, to investigate potential influences of early life exposure to LAN on adult phenotype, we exposed mice to dim (~5 lux; full spectrum white light) or dark (~0 lux) nights pre- and/or postnatally. After weaning at 3 weeks of age, all mice were maintained in dark nights until adulthood (9 weeks of age) when behavior was assessed. Mice exposed to dim light in early life increased anxiety-like behavior and fearful responses on the elevated plus maze and passive avoidance tests. These mice also displayed reduced growth rates, which ultimately normalized during adolescence. mRNA expression of brain derived neurotrophic factor (BDNF), a neurotrophin previously linked to early life environment and adult phenotype, was not altered in the prefrontal cortex or hippocampus by early life LAN exposure. Serum corticosterone concentrations were similar between groups at weaning, suggesting that early life LAN does not elicit a long-term physiologic stress response. Dim light exposure did not influence behavior on the open field, novel object, sucrose anhedonia, or forced swim tests. Our data highlight the potential deleterious consequences of low levels of light during early life to development and subsequent behavior. Whether these changes are due to altered maternal behavior

  4. Identification of mouse retinal genes differentially regulated by dim and bright cyclic light rearing.

    PubMed

    Huang, Hu; Frank, Mark Barton; Dozmorov, Igor; Cao, Wei; Cadwell, Craig; Knowlton, Nick; Centola, Michael; Anderson, Robert E

    2005-05-01

    Bright cyclic light rearing protects BALB/c mice from light-induced photoreceptor apoptosis compared to dim cyclic light rearing. We used a microarray approach to search for putative neuroprotection genes that were up- or down-regulated under these environmental conditions. Retinal protection by bright cyclic rearing was determined by quantitative histology and DNA fragmentation analysis. Total RNA was isolated from 5-week-old mice raised in bright (400 lux) or dim (5 lux) cyclic light and prepared for analysis on microarrays produced using a 70-mer oligonucleotide library that represented 16,463 mouse genes. Genes of interest were identified using statistically robust bioinformatics analysis methods that were developed in-house. Changes in some genes were confirmed with quantitative real time PCR. We found that 952 genes were up- or down-regulated by bright cyclic light rearing compared to dim cyclic light rearing. One hundred and eighty-four of them, having >/=2-fold differences, were grouped into 13 categories, and selected for further consideration. Eleven up-regulated and two down-regulated genes were confirmed by semi-quantitative PCR. Five neuroprotection-associated genes were up-regulated by bright cyclic light rearing as confirmed by real-time PCR. The human orthologue chromosomal location of 22 differentially expressed genes map to known retinal degeneration loci. Using PathwayAssist software, we modeled the pathway networks of up- and down-regulated genes that are functionally related to the retina. We identified retinal genes that are differentially regulated by environmental light history. Those that directly affect cell processes such as survival, apoptosis, and transcription are likely play a pivotal role in the regulation of retinal neuroprotection against light-induced photoreceptor apoptosis.

  5. Is there a transition of solar radiation from dimming to brightening over India?

    NASA Astrophysics Data System (ADS)

    Soni, V. K.; Pandithurai, G.; Pai, D. S.

    2016-03-01

    Recent observational studies show that solar radiation incident on ground has not been stable over the last several decades but underwent significant multi-decadal variations. From the 1950s, solar radiation has had a general decreasing trend, named dimming. Since the late 1980s, a trend reversal and partial recovery has been observed at many observations sites across the globe; it is the so-called brightening. The present study examined temporal and spatial trends in surface solar radiation (global and diffuse) and sunshine duration in India using a 40-year data set (1971-2010) of the twelve stations of solar radiation network of the India Meteorological Department. The research work examines the global solar radiation trends in all-sky and cloud-free sky conditions. The long-term variability in the diffuse components of solar radiation, bright sunshine duration, and cloud cover has also been studied over India. India is one of the few regions that showed a continuous and steady decline in global solar radiation from the 1970s to 2000. The declining trend of all-sky global irradiance over India as a whole was 0.6 Wm- 2 year- 1 during 1971-2000 and 0.2 Wm- 2 year - 1 during 2001-2010. A third-order polynomial fit to the data indicated a reversal in all-sky global irradiance around 2001 at some sites. Reversal or stabilization of global irradiance is also seen in seasonal mean values at some of the stations. The reversal in clear-sky global irradiance was clearly evident from 2001. Similar trend is also observed in bright sunshine duration. This confirms the well-known phenomenon of global dimming and global brightening over India. The analysis of global irradiance data highlights the fact that in general the dimming/brightening is station dependent because of regional sources and meteorology which contribute to the variation in solar irradiance.

  6. Gulf of Mexico Integrated Science - Tampa Bay Study - Data Information Management System (DIMS)

    USGS Publications Warehouse

    Johnston, James

    2004-01-01

    The Tampa Bay Integrated Science Study is an effort by the U.S. Geological Survey (USGS) that combines the expertise of federal, state and local partners to address some of the most pressing ecological problems of the Tampa Bay estuary. This project serves as a template for the application of integrated research projects in other estuaries in the Gulf of Mexico. Efficient information and data distribution for the Tampa Bay Study has required the development of a Data Information Management System (DIMS). This information system is being used as an outreach management tool, providing information to scientists, decision makers and the public on the coastal resources of the Gulf of Mexico.

  7. Home Circadian Phase Assessments with Measures of Compliance Yield Accurate Dim Light Melatonin Onsets

    PubMed Central

    Burgess, Helen J.; Wyatt, James K.; Park, Margaret; Fogg, Louis F.

    2015-01-01

    Study Objectives: There is a need for the accurate assessment of circadian phase outside of the clinic/laboratory, particularly with the gold standard dim light melatonin onset (DLMO). We tested a novel kit designed to assist in saliva sampling at home for later determination of the DLMO. The home kit includes objective measures of compliance to the requirements for dim light and half-hourly saliva sampling. Design: Participants were randomized to one of two 10-day protocols. Each protocol consisted of two back-to-back home and laboratory phase assessments in counterbalanced order, separated by a 5-day break. Setting: Laboratory or participants' homes. Participants: Thirty-five healthy adults, age 21–62 y. Interventions: N/A. Measurements and Results: Most participants received at least one 30-sec epoch of light > 50 lux during the home phase assessments (average light intensity 4.5 lux), but on average for < 9 min of the required 8.5 h. Most participants collected every saliva sample within 5 min of the scheduled time. Ninety-two percent of home DLMOs were not affected by light > 50 lux or sampling errors. There was no significant difference between the home and laboratory DLMOs (P > 0.05); on average the home DLMOs occurred 9.6 min before the laboratory DLMOs. The home DLMOs were highly correlated with the laboratory DLMOs (r = 0.91, P < 0.001). Conclusions: Participants were reasonably compliant to the home phase assessment procedures. The good agreement between the home and laboratory dim light melatonin onsets (DLMOs) demonstrates that including objective measures of light exposure and sample timing during home saliva sampling can lead to accurate home DLMOs. Clinical Trial Registration: Circadian Phase Assessments at Home, http://clinicaltrials.gov/show/NCT01487252, NCT01487252. Citation: Burgess HJ, Wyatt JK, Park M, Fogg LF. Home circadian phase assessments with measures of compliance yield accurate dim light melatonin onsets. SLEEP 2015;38(6):889–897

  8. Human natural killer cell maturation defect supports in vivo CD56(bright) to CD56(dim) lineage development.

    PubMed

    Domaica, Carolina Inés; Fuertes, Mercedes Beatriz; Uriarte, Ignacio; Girart, María Victoria; Sardañons, Jessica; Comas, Dorina Ileana; Di Giovanni, Daniela; Gaillard, María Isabel; Bezrodnik, Liliana; Zwirner, Norberto Walter

    2012-01-01

    Two populations of human natural killer (NK) cells can be identified in peripheral blood. The majority are CD3(-)CD56(dim) cells while the minority exhibits a CD3(-)CD56(bright) phenotype. In vitro evidence indicates that CD56(bright) cells are precursors of CD56(dim) cells, but in vivo evidence is lacking. Here, we studied NK cells from a patient that suffered from a melanoma and opportunistic fungal infection during childhood. The patient exhibited a stable phenotype characterized by a reduction in the frequency of peripheral blood CD3(-)CD56(dim) NK cells, accompanied by an overt increase in the frequency and absolute number of CD3(-)CD56(bright) cells. These NK cells exhibited similar expression of perforin, CD57 and CD158, the major activating receptors CD16, NKp46, NKG2D, DNAM-1, and 2B4, as well as the inhibitory receptor CD94/NKG2A, on both CD56(bright) and CD56(dim) NK cells as healthy controls. Also, both NK cell subpopulations produced IFN-γ upon stimulation with cytokines, and CD3(-)CD56(dim) NK cells degranulated in response to cytokines or K562 cells. However, upon stimulation with cytokines, a substantial fraction of CD56(dim) cells failed to up-regulate CD57 and CD158, showed a reduction in the percentage of CD16(+) cells, and CD56(bright) cells did not down-regulate CD62L, suggesting that CD56(dim) cells could not acquire a terminally differentiated phenotype and that CD56(bright) cells exhibit a maturation defect that might result in a potential altered migration pattern. These observations, support the notion that NK cells of this patient display a maturation/activation defect that precludes the generation of mature NK cells at a normal rate accompanied by CD56(dim) NK cells that cannot completely acquire a terminally differentiated phenotype. Thus, our results provide evidence that support the concept that in vivo CD56(bright) NK cells differentiate into CD56(dim) NK cells, and contribute to further understand human NK cell ontogeny. PMID

  9. Human Natural Killer Cell Maturation Defect Supports In Vivo CD56bright to CD56dim Lineage Development

    PubMed Central

    Domaica, Carolina Inés; Fuertes, Mercedes Beatriz; Uriarte, Ignacio; Girart, María Victoria; Sardañons, Jessica; Comas, Dorina Ileana; Di Giovanni, Daniela; Gaillard, María Isabel; Bezrodnik, Liliana; Zwirner, Norberto Walter

    2012-01-01

    Two populations of human natural killer (NK) cells can be identified in peripheral blood. The majority are CD3−CD56dim cells while the minority exhibits a CD3−CD56bright phenotype. In vitro evidence indicates that CD56bright cells are precursors of CD56dim cells, but in vivo evidence is lacking. Here, we studied NK cells from a patient that suffered from a melanoma and opportunistic fungal infection during childhood. The patient exhibited a stable phenotype characterized by a reduction in the frequency of peripheral blood CD3−CD56dim NK cells, accompanied by an overt increase in the frequency and absolute number of CD3−CD56bright cells. These NK cells exhibited similar expression of perforin, CD57 and CD158, the major activating receptors CD16, NKp46, NKG2D, DNAM-1, and 2B4, as well as the inhibitory receptor CD94/NKG2A, on both CD56bright and CD56dim NK cells as healthy controls. Also, both NK cell subpopulations produced IFN-γ upon stimulation with cytokines, and CD3−CD56dim NK cells degranulated in response to cytokines or K562 cells. However, upon stimulation with cytokines, a substantial fraction of CD56dim cells failed to up-regulate CD57 and CD158, showed a reduction in the percentage of CD16+ cells, and CD56bright cells did not down-regulate CD62L, suggesting that CD56dim cells could not acquire a terminally differentiated phenotype and that CD56bright cells exhibit a maturation defect that might result in a potential altered migration pattern. These observations, support the notion that NK cells of this patient display a maturation/activation defect that precludes the generation of mature NK cells at a normal rate accompanied by CD56dim NK cells that cannot completely acquire a terminally differentiated phenotype. Thus, our results provide evidence that support the concept that in vivo CD56bright NK cells differentiate into CD56dim NK cells, and contribute to further understand human NK cell ontogeny. PMID:23240056

  10. Dim ultraviolet light as a means of deterring activity by the Hawaiian hoary bat Lasiurus cinereus semotus

    USGS Publications Warehouse

    Gorresen, P. Marcos; Cryan, Paul M.; Dalton, David C.; Wolf, Sandy; Johnson, Jessica A.; Todd, Christopher M.; Bonaccorso, Frank J.

    2015-01-01

    Widespread bat fatalities at industrial wind turbines are a conservation issue with the potential to inhibit efficient use of an abundant source of energy. Bat fatalities can be reduced by altering turbine operations, but such curtailment decreases turbine efficiency. If additional ways of reducing bat fatalities at wind turbines were available such tradeoffs might not be needed. Based on the facts that bats perceive distant objects primarily through vision and can see in very dim lighting conditions, and the possibility that bats might interact with turbines after approaching them as they would trees, we propose a novel method of reducing bat activity at wind turbines: illumination of the structure with dim light. As a first step toward assessing this approach, we illuminated trees with dim flickering ultraviolet (UV) light in areas frequented by Hawaiian hoary bats Lasiurus cinereus semotus, an endangered subspecies affected by wind turbines. We used a repeated-measures design to quantify bat activity near trees with acoustic detectors and thermal video cameras in the presence and absence of UV illumination, while concurrently monitoring insect numbers. Results indicate that dim UV reduces bat activity despite an increase in insect numbers. Experimental treatment did not completely inhibit bat activity near trees, nor did all measures of bat activity show statistically significant differences due to high variance in bat activity among sites. However, the observed decreases in bat activity with dim UV illumination justify further testing of this method as a means to reduce bat fatalities at wind turbines.

  11. Penalty Dynamic Programming Algorithm for Dim Targets Detection in Sensor Systems

    PubMed Central

    Huang, Dayu; Xue, Anke; Guo, Yunfei

    2012-01-01

    In order to detect and track multiple maneuvering dim targets in sensor systems, an improved dynamic programming track-before-detect algorithm (DP-TBD) called penalty DP-TBD (PDP-TBD) is proposed. The performances of tracking techniques are used as a feedback to the detection part. The feedback is constructed by a penalty term in the merit function, and the penalty term is a function of the possible target state estimation, which can be obtained by the tracking methods. With this feedback, the algorithm combines traditional tracking techniques with DP-TBD and it can be applied to simultaneously detect and track maneuvering dim targets. Meanwhile, a reasonable constraint that a sensor measurement can originate from one target or clutter is proposed to minimize track separation. Thus, the algorithm can be used in the multi-target situation with unknown target numbers. The efficiency and advantages of PDP-TBD compared with two existing methods are demonstrated by several simulations. PMID:22666074

  12. Global dimming and urbanization: did stronger negative SSR trends collocate with regions of population growth?

    NASA Astrophysics Data System (ADS)

    Imamovic, Adel; Tanaka, Katsumasa; Folini, Doris; Wild, Martin

    2016-04-01

    Global dimming refers to the decrease in surface solar radiation (SSR) observed from the 1960s to the 1980s at different measurement sites all around the world. It is under debate whether anthropogenic aerosols emitted from urban areas close to the measurement sites are mainly responsible for the dimming. In order to assess this urbanization impact on SSR, we use spatially explicit population density data of 0.08° resolution to construct population indices (PI) at 157 high data quality sites. Our study extends previous population-based studies by incorporating distance-weighting as a simple aerosol diffusion model. We measured urbanization in the surrounding of a site as the PI change form 1960 to 1990 and found no negative correlation with the corresponding SSR trends from 1964 to 1989 for the 92 sites in Europe and Japan. For the 39 sites in China the correlation coefficients are significant at the 5 % level and reach around ‑0.35, while for the 26 remaining Asian, mostly Russian sites the correlation coefficients reach around ‑0.55 at the 1 % significance level. Results are similar, when the absolute levels of PIs are taken as an indicator for urbanization. Our findings call into question the existence of an urbanization effect for the sites in Europe and Japan, while such an effect cannot be ruled out for the sites in Asia, especially in Russia.

  13. Inference of Dim Gamma-Ray Point Sources Using Probabilistic Catalogues

    NASA Astrophysics Data System (ADS)

    Daylan, Tansu; Portillo, Stephen K. N.; Finkbeiner, Douglas P.

    2016-07-01

    Poisson regression of the Fermi-LAT data in the inner Milky Way reveals an extended gamma-ray excess. The anomalous emission falls steeply away from the galactic center and has an energy spectrum that peaks at 1-2 GeV. An important question is whether the signal is coming from a collection of unresolved point sources, possibly recycled pulsars, or constitutes a truly diffuse emission component. Previous analyses have relied on non-Poissonian template fits or wavelet decomposition of the Fermi-LAT data, which find evidence for a population of dim point sources just below the 3FGL flux limit. In order to draw conclusions about a potentially dim population, we propose to sample from the catalog space of point sources, where the model dimensionality, i.e., the number of sources, is unknown. Although being a computationally expensive sampling problem, this approach allows us to infer the number, flux and radial distribution of the point sources consistent with the observed count data. Probabilistic cataloging is specifically useful in the crowded field limit, such as in the galactic disk, where the typical separation between point sources is comparable to the PSF. Using this approach, we recover the results of the deterministic Fermi-LAT 3FGL catalog, as well as sub-detection threshold information and fold the point source parameter degeneracies into the model-choice problem of whether an emission is coming from unresolved MSPs or dark matter annihilation.

  14. Adaptive local backlight dimming algorithm based on local histogram and image characteristics

    NASA Astrophysics Data System (ADS)

    Nadernejad, Ehsan; Burini, Nino; Korhonen, Jari; Forchhammer, Søren; Mantel, Claire

    2013-02-01

    Liquid Crystal Display (LCDs) with Light Emitting Diode (LED) backlight is a very popular display technology, used for instance in television sets, monitors and mobile phones. This paper presents a new backlight dimming algorithm that exploits the characteristics of the target image, such as the local histograms and the average pixel intensity of each backlight segment, to reduce the power consumption of the backlight and enhance image quality. The local histogram of the pixels within each backlight segment is calculated and, based on this average, an adaptive quantile value is extracted. A classification into three classes based on the average luminance value is performed and, depending on the image luminance class, the extracted information on the local histogram determines the corresponding backlight value. The proposed method has been applied on two modeled screens: one with a high resolution direct-lit backlight, and the other screen with 16 edge-lit backlight segments placed in two columns and eight rows. We have compared the proposed algorithm against several known backlight dimming algorithms by simulations; and the results show that the proposed algorithm provides better trade-off between power consumption and image quality preservation than the other algorithms representing the state of the art among feature based backlight algorithms.

  15. Phototropin 1 and dim-blue light modulate the red light de-etiolation response.

    PubMed

    Wang, Yihai; M Folta, Kevin

    2014-01-01

    Light signals regulate seedling morphological changes during de-etiolation through the coordinated actions of multiple light-sensing pathways. Previously we have shown that red-light-induced hypocotyl growth inhibition can be reversed by addition of dim blue light through the action of phototropin 1 (phot1). Here we further examine the fluence-rate relationships of this blue light effect in short-term (hours) and long-term (days) hypocotyl growth assays. The red stem-growth inhibition and blue promotion is a low-fluence rate response, and blue light delays or attenuates both the red light and far-red light responses. These de-etiolation responses include blue light reversal of red or far-red induced apical hook opening. This response also requires phot1. Cryptochromes (cry1 and cry2) are activated by higher blue light fluence-rates and override phot1's influence on hypocotyl growth promotion. Exogenous application of auxin transport inhibitor naphthylphthalamic acid abolished the blue light stem growth promotion in both hypocotyl growth and hook opening. Results from the genetic tests of this blue light effect in auxin transporter mutants, as well as phytochrome kinase substrate mutants indicated that aux1 may play a role in blue light reversal of red light response. Together, the phot1-mediated adjustment of phytochrome-regulated photomorphogenic events is most robust in dim blue light conditions and is likely modulated by auxin transport through its transporters. PMID:25482790

  16. Global dimming and urbanization: did stronger negative SSR trends collocate with regions of population growth?

    NASA Astrophysics Data System (ADS)

    Imamovic, Adel; Tanaka, Katsumasa; Folini, Doris; Wild, Martin

    2016-04-01

    Global dimming refers to the decrease in surface solar radiation (SSR) observed from the 1960s to the 1980s at different measurement sites all around the world. It is under debate whether anthropogenic aerosols emitted from urban areas close to the measurement sites are mainly responsible for the dimming. In order to assess this urbanization impact on SSR, we use spatially explicit population density data of 0.08° resolution to construct population indices (PI) at 157 high data quality sites. Our study extends previous population-based studies by incorporating distance-weighting as a simple aerosol diffusion model. We measured urbanization in the surrounding of a site as the PI change form 1960 to 1990 and found no negative correlation with the corresponding SSR trends from 1964 to 1989 for the 92 sites in Europe and Japan. For the 39 sites in China the correlation coefficients are significant at the 5 % level and reach around -0.35, while for the 26 remaining Asian, mostly Russian sites the correlation coefficients reach around -0.55 at the 1 % significance level. Results are similar, when the absolute levels of PIs are taken as an indicator for urbanization. Our findings call into question the existence of an urbanization effect for the sites in Europe and Japan, while such an effect cannot be ruled out for the sites in Asia, especially in Russia.

  17. Global dimming and urbanization: did stronger negative SSR trends collocate with regions of population growth?

    NASA Astrophysics Data System (ADS)

    Imamovic, Adel; Tanaka, Katsumasa; Folini, Doris; Wild, Martin

    2016-03-01

    Global dimming refers to the decrease in surface solar radiation (SSR) observed from the 1960s to the 1980s at different measurement sites all around the world. It is under debate whether anthropogenic aerosols emitted from urban areas close to the measurement sites are mainly responsible for the dimming. In order to assess this urbanization impact on SSR, we use spatially explicit population density data of 0.08° resolution to construct population indices (PI) at 157 high data quality sites. Our study extends previous population-based studies by incorporating distance-weighting as a simple aerosol diffusion model. We measured urbanization in the surrounding of a site as the PI change from 1960 to 1990 and found no negative correlation with the corresponding SSR trends from 1964 to 1989 for the 92 sites in Europe and Japan. For the 39 sites in China the correlation coefficients are significant at the 5 % level and reach around -0.35, while for the 26 remaining Asian, mostly Russian sites the correlation coefficients reach around -0.55 at the 1 % significance level. Results are similar, when the absolute levels of PIs are taken as an indicator for urbanization. Our findings call into question the existence of an urbanization effect for the sites in Europe and Japan, while such an effect cannot be ruled out for the sites in Asia, especially in Russia.

  18. Global dimming and urbanization: did stronger negative SSR trends collocate with regions of population growth?

    NASA Astrophysics Data System (ADS)

    Imamovic, A.; Tanaka, K.; Folini, D.; Wild, M.

    2015-11-01

    Global dimming refers to the decrease in surface solar radiation (SSR) observed from the 1960s to the 1980s at different measurement sites all around the world. It is under debate whether anthropogenic aerosols emitted from urban areas close to the measurement sites are mainly responsible for the dimming. In order to assess this urbanization impact on SSR, we use spatially explicit population density data of 0.08° resolution to construct population indices (PI) at 157 high data quality sites. Our study extends previous population-based studies by incorporating distance-weighting as a simple aerosol diffusion model. We measured urbanization in the surrounding of a site as the PI change form 1960 to 1990 and found no negative correlation with the corresponding SSR trends from 1964 to 1989 for the 92 sites in Europe and Japan. For the 39 sites in China the correlation coefficients are significant at the 5 % level and reach around -0.35, while for the 26 remaining Asian, mostly Russian sites the correlation coefficients reach around -0.55 at the 1 % significance level. Results are similar, when the absolute levels of PIs are taken as an indicator for urbanization. Our findings call into question the existence of an urbanization effect for the sites in Europe and Japan, while such an effect cannot be ruled out for the sites in Asia, especially in Russia.

  19. Effects of solar dimming and brightening on the terrestrial carbon sink

    NASA Astrophysics Data System (ADS)

    Mercado, L.; Bellouin, N.; Sitch, S.; Boucher, O.; Huntingford, C.; Wild, M.; Cox, P. M.

    2009-04-01

    Plant photosynthesis increases with solar radiation. Recent studies have shown that photosynthesis is more efficient under diffuse light conditions (Gu et al., 2003, Niyogi et al., 2004, Oliveira et al., 2007, Roderick et al., 2001). Changes in cloud cover and atmospheric aerosol loadings from either volcanic and anthropogenic sources, modify the total radiation reaching the surface and the fraction of this radiation which is diffuse, with uncertain overall effects on plant productivity and the global land carbon sink. A decrease in total solar radiation (Liepert, 2002, Stanhill and Cohen, 2001, Wild et al., 2005) has been observed at the Earth surface over the 1950-1990 period, called solar dimming. Such dimming gradually started to transform into brightening in some regions of the world since the late 1980s (Wild et al. 2005). The effect of these changes in total solar radiation and associated changes in diffuse radiation and diffuse fraction on the land biosphere has not yet been accounted for in global carbon cycle simulations because such models lack the mechanism that includes the diffuse irradiance effects on photosynthesis In this study we estimate the total impact of variations in clouds and atmospheric aerosols on the land carbon sink using a global land carbon cycle model modified to account for the effects of variations in both direct and diffuse radiation on canopy photosynthesis (Mercado et al., 2007) during the global dimming and brightening period. References Gu L.H., Baldocchi D.D., Wofsy S.C., Munger J.W., Michalsky J.J., Urbanski S.P. & Boden T.A. (2003) Response of a deciduous forest to the Mount Pinatubo eruption: Enhanced photosynthesis. Science, 299, 2035-2038. Liepert B.G. (2002) Observed reductions of surface solar radiation at sites in the United States and worldwide from 1961 to 1990. 29, 1421. Mercado L.M., Huntingford C., Gash J.H.C., Cox P.M. & Jogireddy V. (2007) Improving the representation of radiation interception and

  20. Adaptive one-dimensional dimming technique for liquid crystal displays with low power consumption and high image quality

    NASA Astrophysics Data System (ADS)

    Kim, Seung-Ryeol; Lee, Seung-Woo

    2015-07-01

    An adaptive one-dimensional (1-D) dimming technique for liquid crystal displays that compensates for nonuniform backlight distribution is proposed. Dimming techniques that do not consider luminance distribution may cause severe visual artifacts, such as a block artifact. However, an adaptive 1-D dimming technique that considers luminance distribution can reduce power consumption without causing any visual artifacts. Hardware implementation results verified that our method achieved lower power consumption compared to nondimming techniques and removed block artifacts from International Electrotechnical Commission 62087 standard images. The power consumption using the proposed method ranged from 85.5% to 94.7% compared to nondimming techniques. Furthermore, the contrast ratio increased by up to 231% and 165% on average compared to nondimming techniques.

  1. Integrated fluorescence analysis system

    DOEpatents

    Buican, Tudor N.; Yoshida, Thomas M.

    1992-01-01

    An integrated fluorescence analysis system enables a component part of a sample to be virtually sorted within a sample volume after a spectrum of the component part has been identified from a fluorescence spectrum of the entire sample in a flow cytometer. Birefringent optics enables the entire spectrum to be resolved into a set of numbers representing the intensity of spectral components of the spectrum. One or more spectral components are selected to program a scanning laser microscope, preferably a confocal microscope, whereby the spectrum from individual pixels or voxels in the sample can be compared. Individual pixels or voxels containing the selected spectral components are identified and an image may be formed to show the morphology of the sample with respect to only those components having the selected spectral components. There is no need for any physical sorting of the sample components to obtain the morphological information.

  2. Outcomes from Enabling Courses.

    ERIC Educational Resources Information Center

    Phan, Oanh; Ball, Katrina

    The outcomes of enabling courses offered in Australia's vocational education and training (VET) sector were examined. "Enabling course" was defined as lower-level preparatory and prevocational courses covering a wide range of areas, including remedial education, bridging courses, precertificate courses, and general employment preparation courses.…

  3. Technology Enabled Learning. Symposium.

    ERIC Educational Resources Information Center

    2002

    This document contains three papers on technology-enabled learning and human resource development. Among results found in "Current State of Technology-enabled Learning Programs in Select Federal Government Organizations: a Case Study of Ten Organizations" (Letitia A. Combs) are the following: the dominant delivery method is traditional…

  4. [Study on Hexagonal Super-Lattice Pattern with Light Spot and Dim Spot in Dielectric Barrier Discharge by Optical Emission Spectra].

    PubMed

    Liu, Ying; Dong, Li-fang; Niu, Xue-jiao; Zhang, Chao

    2016-02-01

    The hexagonal super-lattice pattern composed of the light spot and the dim spot is firstly observed and investigated in the discharge of gas mixture of air and argon by using the dielectric barrier discharge device with double water electrodes. It is found that the dim spot is located at the center of its surrounding three light spots by observing the discharge image. Obviously, the brightness of the light spot and the dim spot are different, which indicates that the plasma states of the light spot and the dim spot may be different. The optical emission spectrum method is used to further study the several plasma parameters of the light spot and the dim spot in different argon content. The emission spectra of the N₂ second positive band (C³IIu --> B³IIg) are measured, from which the molecule vibration temperatures of the light spot and the dim spot are calculated. Based on the relative intensity ratio of the line at 391.4 nm and the N₂ line at 394.1 nm, the average electron energies of the light spot and the dim spot are investigated. The broadening of spectral line 696.57 nm (2P₂-1S₅) is used to study the electron densities of the light spot and the dim spot. The experiment shows that the molecule vibration temperature, average electron energy and the electron density of the dim spot are higher than those of the light spot in the same argon content. The molecule vibration temperature and electron density of the light spot and dim spot increase with the argon content increasing from 70% to 95%, while average electron energies of the light spot and dim spot decrease gradually. The short-exposure image recorded by a high speed video camera shows that the dim spot results from the surface discharges (SDs). The surface discharge induced by the volume discharge (VD) has the decisive effect on the formation of the dim spot. The experiment above plays an important role in studying the formation mechanism of the hexagonal super-lattice pattern with light spot and

  5. Highlighting metabolic indicators of olive oil during storage by the AComDim method.

    PubMed

    Korifi, R; Plard, J; Le Dréau, Y; Rébufa, C; Rutledge, D N; Dupuy, N

    2016-07-15

    Lipid oxidation during olive oil storage induces changes in the metabolite content of the oil, which can be measured using so-called quality indices. High values indicate poor quality oils that should be labeled accordingly or removed from the market. Based on quality indices measured over two years for two olive oils, the AComDim method was used to highlight the influence of five factors (olive oil type, oxygen, light, temperature and storage time) on oxidative stability during storage. To identify the significant factors, two full factorial experimental designs were built, each containing four of the five factors examined. The results showed that all five factors, as well as some two-factor interactions, were significant. Phenols and hydroperoxides were identified as being the most sensitive to these factors, and potential markers for the ageing of olive oil.

  6. Soil transformation of wheat and corn metabolites mboa and DIM2BOA into aminophenoxazinones.

    PubMed

    Kumar, P; Gagliardo, R W; Chilton, W S

    1993-11-01

    The defensive cyclic hydroxamates 7-methoxy-2,4-dihydroxy-1,4(2H)-benzoxazin-3-one (DIMBOA) and 7,8-dimethoxy-2,4-dihydroxy-1,4(2H)-benzoxazin-3-one (DIM2BOA) of wheat and corn are transformed in nonsterile soil, via 6-methoxy-2(3H)-benzoxazolone (MBOA) and 6,7-dimethoxy-2(3H)-benzoxazolone (M2BOA) respectively, into 2-amino-7-methoxy-3H-phenoxazin-3-one and 2-amino-4,6,7-trimethoxy-3H-phenoxazin-3-one. The soil transformation is similar of that undergone by the rye metabolite 2(3H)-benzoxazolone (BOA) into 2-amino-3H-phenoxazin-3-one. The transformations to phenoxazinones are not observed in sterile soil. The 2-amino-3H-phenoxazin-3-one inhibits barnyard grass radicle elongation, but the methoxylated aminophenoxazinones are not significantly inhibitory.

  7. Highlighting metabolic indicators of olive oil during storage by the AComDim method.

    PubMed

    Korifi, R; Plard, J; Le Dréau, Y; Rébufa, C; Rutledge, D N; Dupuy, N

    2016-07-15

    Lipid oxidation during olive oil storage induces changes in the metabolite content of the oil, which can be measured using so-called quality indices. High values indicate poor quality oils that should be labeled accordingly or removed from the market. Based on quality indices measured over two years for two olive oils, the AComDim method was used to highlight the influence of five factors (olive oil type, oxygen, light, temperature and storage time) on oxidative stability during storage. To identify the significant factors, two full factorial experimental designs were built, each containing four of the five factors examined. The results showed that all five factors, as well as some two-factor interactions, were significant. Phenols and hydroperoxides were identified as being the most sensitive to these factors, and potential markers for the ageing of olive oil. PMID:26948595

  8. Dim nighttime light impairs cognition and provokes depressive-like responses in a diurnal rodent.

    PubMed

    Fonken, Laura K; Kitsmiller, Emily; Smale, Laura; Nelson, Randy J

    2012-08-01

    Circadian disruption is a common by-product of modern life. Although jet lag and shift work are well-documented challenges to circadian organization, many more subtle environmental changes cause circadian disruption. For example, frequent fluctuations in the timing of the sleep/wake schedule, as well as exposure to nighttime lighting, likely affect the circadian system. Most studies of these effects have focused on nocturnal rodents, which are very different from diurnal species with respect to their patterns of light exposure and the effects that light can have on their activity. Thus, the authors investigated the effect of nighttime light on behavior and the brain of a diurnal rodent, the Nile grass rat. Following 3 weeks of exposure to standard light/dark (LD; 14:10 light [~150 lux] /dark [0 lux]) or dim light at night (dLAN; 14:10 light [~150 lux] /dim [5 lux]), rats underwent behavioral testing, and hippocampal neurons within CA1, CA3, and the dentate gyrus (DG) were examined. Three behavioral effects of dLAN were observed: (1) decreased preference for a sucrose solution, (2) increased latency to float in a forced swim test, and (3) impaired learning and memory in the Barnes maze. Light at night also reduced dendritic length in DG and basilar CA1 dendrites. Dendritic length in the DG positively correlated with sucrose consumption in the sucrose anhedonia task. Nighttime light exposure did not disrupt the pattern of circadian locomotor activity, and all grass rats maintained a diurnal activity pattern. Together, these data suggest that exposure to dLAN can alter affective responses and impair cognition in a diurnal animal.

  9. Sparse Representation for Infrared Dim Target Detection via a Discriminative Over-Complete Dictionary Learned Online

    PubMed Central

    Li, Zheng-Zhou; Chen, Jing; Hou, Qian; Fu, Hong-Xia; Dai, Zhen; Jin, Gang; Li, Ru-Zhang; Liu, Chang-Ju

    2014-01-01

    It is difficult for structural over-complete dictionaries such as the Gabor function and discriminative over-complete dictionary, which are learned offline and classified manually, to represent natural images with the goal of ideal sparseness and to enhance the difference between background clutter and target signals. This paper proposes an infrared dim target detection approach based on sparse representation on a discriminative over-complete dictionary. An adaptive morphological over-complete dictionary is trained and constructed online according to the content of infrared image by K-singular value decomposition (K-SVD) algorithm. Then the adaptive morphological over-complete dictionary is divided automatically into a target over-complete dictionary describing target signals, and a background over-complete dictionary embedding background by the criteria that the atoms in the target over-complete dictionary could be decomposed more sparsely based on a Gaussian over-complete dictionary than the one in the background over-complete dictionary. This discriminative over-complete dictionary can not only capture significant features of background clutter and dim targets better than a structural over-complete dictionary, but also strengthens the sparse feature difference between background and target more efficiently than a discriminative over-complete dictionary learned offline and classified manually. The target and background clutter can be sparsely decomposed over their corresponding over-complete dictionaries, yet couldn't be sparsely decomposed based on their opposite over-complete dictionary, so their residuals after reconstruction by the prescribed number of target and background atoms differ very visibly. Some experiments are included and the results show that this proposed approach could not only improve the sparsity more efficiently, but also enhance the performance of small target detection more effectively. PMID:24871988

  10. Another deep dimming of the classical T Tauri star RW Aurigae A

    NASA Astrophysics Data System (ADS)

    Petrov, P. P.; Gahm, G. F.; Djupvik, A. A.; Babina, E. V.; Artemenko, S. A.; Grankin, K. N.

    2015-05-01

    Context. RW Aur A is a classical T Tauri star (CTTS) with an unusually rich emission line spectrum. In 2014 the star faded by ~3 mag in the V band and went into a long-lasting minimum. In 2010 the star underwent a similar fading, although less pronounced. These events in RW Aur A are very unusual among the CTTS, and have been attributed to occultations by passing dust clouds. Aims: We want to find out if any spectral changes took place after the last fading of RW Aur A with the intention of gathering more information on the occulting body and the cause of the phenomenon. Methods: We collected spectra of the two components of RW Aur. The photometry was performed before and during the minimum. Results: The overall spectral signatures reflecting emission from accretion flows from disk to star did not change after the fading. However, blue-shifted absorption components related to the stellar wind increased in strength in certain resonance lines, and the profiles and strengths but not the fluxes of forbidden lines became drastically different. Conclusions: The extinction through the obscuring cloud is grey indicating the presence of large dust grains. At the same time, there are no traces of related absorbing gas. The cloud occults the star and the interior part of the stellar wind, but not the wind or jet further out. The dimming in 2014 was not accompanied by changes in the accretion flows at the stellar surface. There is evidence that the structure and velocity pattern of the stellar wind did change significantly. The dimmings could be related to passing condensations in a tidally disrupted disk, as proposed earlier, but we also speculate that large dust grains have been stirred up from the inclined disk into the line of sight through the interaction with an enhanced wind. Based on observations collected at the Nordic Optical Telescope, La Palma, Spain; Fast-Track Service program 50-409.

  11. The hockey-stick method to estimate evening dim light melatonin onset (DLMO) in humans.

    PubMed

    Danilenko, Konstantin V; Verevkin, Evgeniy G; Antyufeev, Viktor S; Wirz-Justice, Anna; Cajochen, Christian

    2014-04-01

    The onset of melatonin secretion in the evening is the most reliable and most widely used index of circadian timing in humans. Saliva (or plasma) is usually sampled every 0.5-1 hours under dim-light conditions in the evening 5-6 hours before usual bedtime to assess the dim-light melatonin onset (DLMO). For many years, attempts have been made to find a reliable objective determination of melatonin onset time either by fixed or dynamic threshold approaches. The here-developed hockey-stick algorithm, used as an interactive computer-based approach, fits the evening melatonin profile by a piecewise linear-parabolic function represented as a straight line switching to the branch of a parabola. The switch point is considered to reliably estimate melatonin rise time. We applied the hockey-stick method to 109 half-hourly melatonin profiles to assess the DLMOs and compared these estimates to visual ratings from three experts in the field. The DLMOs of 103 profiles were considered to be clearly quantifiable. The hockey-stick DLMO estimates were on average 4 minutes earlier than the experts' estimates, with a range of -27 to +13 minutes; in 47% of the cases the difference fell within ±5 minutes, in 98% within -20 to +13 minutes. The raters' and hockey-stick estimates showed poor accordance with DLMOs defined by threshold methods. Thus, the hockey-stick algorithm is a reliable objective method to estimate melatonin rise time, which does not depend on a threshold value and is free from errors arising from differences in subjective circadian phase estimates. The method is available as a computerized program that can be easily used in research settings and clinical practice either for salivary or plasma melatonin values.

  12. Dim nighttime light impairs cognition and provokes depressive-like responses in a diurnal rodent.

    PubMed

    Fonken, Laura K; Kitsmiller, Emily; Smale, Laura; Nelson, Randy J

    2012-08-01

    Circadian disruption is a common by-product of modern life. Although jet lag and shift work are well-documented challenges to circadian organization, many more subtle environmental changes cause circadian disruption. For example, frequent fluctuations in the timing of the sleep/wake schedule, as well as exposure to nighttime lighting, likely affect the circadian system. Most studies of these effects have focused on nocturnal rodents, which are very different from diurnal species with respect to their patterns of light exposure and the effects that light can have on their activity. Thus, the authors investigated the effect of nighttime light on behavior and the brain of a diurnal rodent, the Nile grass rat. Following 3 weeks of exposure to standard light/dark (LD; 14:10 light [~150 lux] /dark [0 lux]) or dim light at night (dLAN; 14:10 light [~150 lux] /dim [5 lux]), rats underwent behavioral testing, and hippocampal neurons within CA1, CA3, and the dentate gyrus (DG) were examined. Three behavioral effects of dLAN were observed: (1) decreased preference for a sucrose solution, (2) increased latency to float in a forced swim test, and (3) impaired learning and memory in the Barnes maze. Light at night also reduced dendritic length in DG and basilar CA1 dendrites. Dendritic length in the DG positively correlated with sucrose consumption in the sucrose anhedonia task. Nighttime light exposure did not disrupt the pattern of circadian locomotor activity, and all grass rats maintained a diurnal activity pattern. Together, these data suggest that exposure to dLAN can alter affective responses and impair cognition in a diurnal animal. PMID:22855576

  13. Sparse representation for infrared Dim target detection via a discriminative over-complete dictionary learned online.

    PubMed

    Li, Zheng-Zhou; Chen, Jing; Hou, Qian; Fu, Hong-Xia; Dai, Zhen; Jin, Gang; Li, Ru-Zhang; Liu, Chang-Ju

    2014-01-01

    It is difficult for structural over-complete dictionaries such as the Gabor function and discriminative over-complete dictionary, which are learned offline and classified manually, to represent natural images with the goal of ideal sparseness and to enhance the difference between background clutter and target signals. This paper proposes an infrared dim target detection approach based on sparse representation on a discriminative over-complete dictionary. An adaptive morphological over-complete dictionary is trained and constructed online according to the content of infrared image by K-singular value decomposition (K-SVD) algorithm. Then the adaptive morphological over-complete dictionary is divided automatically into a target over-complete dictionary describing target signals, and a background over-complete dictionary embedding background by the criteria that the atoms in the target over-complete dictionary could be decomposed more sparsely based on a Gaussian over-complete dictionary than the one in the background over-complete dictionary. This discriminative over-complete dictionary can not only capture significant features of background clutter and dim targets better than a structural over-complete dictionary, but also strengthens the sparse feature difference between background and target more efficiently than a discriminative over-complete dictionary learned offline and classified manually. The target and background clutter can be sparsely decomposed over their corresponding over-complete dictionaries, yet couldn't be sparsely decomposed based on their opposite over-complete dictionary, so their residuals after reconstruction by the prescribed number of target and background atoms differ very visibly. Some experiments are included and the results show that this proposed approach could not only improve the sparsity more efficiently, but also enhance the performance of small target detection more effectively.

  14. Effects of diurnal bright/dim light intensity on circadian core temperature and activity rhythms in the Japanese macaque.

    PubMed

    Takasu, Nana; Nigi, Hideo; Tokura, Hiromi

    2002-12-01

    Circadian rhythms of core temperature and activity were studied using three Japanese macaques under influences of two different light intensities during the daytime. Nocturnal core temperature and activity onset time were lower and advanced, respectively, in bright as compared to dim light. These results suggest the possibility that diurnal bright light could influence the circadian organization.

  15. CALiPER Retail Lamps Study 3.1: Dimming, Flicker, and Power Quality Characteristics of LED A Lamps

    SciTech Connect

    none,

    2014-12-31

    This CALiPER report examines the characteristics of a subset of lamps from CALiPER Retail Lamps Study 3 in more detail. Specifically, it focuses on the dimming, power quality, and flicker characteristics of 14 LED A lamps, as controlled by four different retail-available dimmers.

  16. ATTENUATION OF MULTI-TARGETED PROLIFERATION-LINKED SIGNALING BY 3,3′-DIINDOLYLMETHANE (DIM): FROM BENCH TO CLINIC

    PubMed Central

    Banerjee, Sanjeev; Kong, Dejuan; Wang, Zhiwei; Bao, Bin; Hillman, Gilda G; Sarkar, Fazlul H

    2013-01-01

    Emerging evidence provide credible support in favor of the potential role of bioactive products derived from ingesting cruciferous vegetables such as broccoli, brussel sprouts, cauliflower and cabbage. Among many compounds, 3,3′-Diindolylmethane (DIM) is generated in the acidic environment of the stomach following dimerization of Indole-3-Carbinol (I3C) monomers present in these classes of vegetables. Both I3C and DIM have been investigated for their use in preventing, inhibiting, and reversing the progression of cancer- as a chemopreventive agent. In this review, we summarize an updated, wide-ranging pleiotropic anti-tumor and biological effects elicited by DIM against tumor cells. It is unfeasible to point one single target as basis of cellular target of action of DIM. We emphasize key cellular and molecular events that are effectively modulated in the direction of inducing apoptosis and suppressing cell proliferation. Collectively, DIM orchestrates signaling through Ah receptor, NF-κB/Wnt/Akt/mTOR pathways impinging on cell cycle arrest, modulation of key cytochrome P450 enzymes, altering angiogenesis, invasion, metastasis and epigenetic behaviors of cancer cells. The ability of DIM to selectively induce tumor cells to undergo apoptosis has been observed in preclinical models, and thus it has been speculated in improving the therapeutic efficacy of other anticancer agents that have diverse molecular targets. Consequently, DIM has moved through preclinical development into phase-I clinical trials, thereby suggesting that DIM could be a promising and novel agent either alone or as an adjunct to conventional therapeutics such as chemo-radio therapy, and targeted therapies. An important development has been the availability of DIM formulation with superior bioavailability for humans. Therefore, DIM appears to be a promising chemopreventive agent or chemo-radio-sensitizer for the prevention of tumor recurrence and/or for the treatment of human malignancies. PMID

  17. A Predictor--Corrector Method for the 3--DIM Restoration of GRISM and Slitless Spectra; Tools for NICMOS and STIS.

    NASA Astrophysics Data System (ADS)

    Caulet, A.

    1996-12-01

    Grism or slitless spectroscopy can provide spectroscopic information of all objects in the detector field of view (FOV). Because of overlapping and object crowding, in practice, only stellar objects are exploited; most extended objects are discarded, except when some obvious emission line can be isolated. The goal of this work has been to produce an efficient code that restores the full capability of image--spectroscopy. A set of data consists of grism (or slitless) images of a given field observed at 4 different roll--angles, and for each roll-angle, an image for field identification. The IDL code is based on a predictor--corrector iterative method. The method is used to restore the true spectra of extended sources appropriate to spectroscopic observations with the new HST instruments (NICMOS, STIS). The FOV is the Hubble Deep Field. First, each pixel is given an input ``true" spectrum. Simulations of 2--DIM grism images for 4 different roll-angles are made (DATA). Then, the code calculates the first spectral data cube (3--DIM MODEL, images for each sampled wavelength) by combining the 2--DIM DATA for each point in the sky for all wavelengths. This data cube is used to simulate new 2--DIM grism images (PRED). The image ratios PRED/DATA for the 4 roll-angles are combined and used to correct the previous 3--DIM MODEL. And so on, until convergence (via chi2). Appropriate masking and normalization are made; this ensures that no false object appears. With 4 roll-angles, the true spectra are restored in about 30 iterations, i.e. 5 hours on a Sparc 20/502 running Solaris 2.4. For each iteration, error pixel maps are calculated to assess how well the DATA can be predicted. The final error maps are attached to the final 3--DIM restored cube and can be used for further data analysis. The code does not use (de)convolution. The PSFs can be measured from the final cube for each wavelength, from stars in the field. 2--DIM spatial deconvolution can be made after restoration

  18. Nanoproteomics enabling personalized nanomedicine.

    PubMed

    Nicolini, Claudio; Bragazzi, Nicola; Pechkova, Eugenia

    2012-10-01

    Nucleic Acid Programmable Protein Arrays utilize a complex mammalian cell free expression system to produce proteins in situ. In alternative to fluorescent-labeled approaches a new label free method, emerging from the combined utilization of three independent and complementary nanotechnological approaches, appears capable to analyze protein function and protein-protein interaction in studies promising for personalized medicine. Quartz Micro Circuit nanogravimetry, based on frequency and dissipation factor, mass spectrometry and anodic porous alumina overcomes indeed the limits of correlated fluorescence detection plagued by the background still present after extensive washes. This could be further optimized by a homogeneous and well defined bacterial cell free expression system capable to realize the ambitious objective to quantify the regulatory protein networks in humans. Implications for personalized medicine of the above label free protein array using different test genes proteins are reported.

  19. Fluorescent refrigeration

    DOEpatents

    Epstein, Richard I.; Edwards, Bradley C.; Buchwald, Melvin I.; Gosnell, Timothy R.

    1995-01-01

    Fluorescent refrigeration is based on selective radiative pumping, using substantially monochromatic radiation, of quantum excitations which are then endothermically redistributed to higher energies. Ultimately, the populated energy levels radiatively deexcite emitting, on the average, more radiant energy than was initially absorbed. The material utilized to accomplish the cooling must have dimensions such that the exciting radiation is strongly absorbed, but the fluorescence may exit the material through a significantly smaller optical pathlength. Optical fibers and mirrored glasses and crystals provide this requirement.

  20. Physician Enabling Skills Questionnaire

    PubMed Central

    Hudon, Catherine; Lambert, Mireille; Almirall, José

    2015-01-01

    Abstract Objective To evaluate the reliability and validity of the newly developed Physician Enabling Skills Questionnaire (PESQ) by assessing its internal consistency, test-retest reliability, concurrent validity with patient-centred care, and predictive validity with patient activation and patient enablement. Design Validation study. Setting Saguenay, Que. Participants One hundred patients with at least 1 chronic disease who presented in a waiting room of a regional health centre family medicine unit. Main outcome measures Family physicians’ enabling skills, measured with the PESQ at 2 points in time (ie, while in the waiting room at the family medicine unit and 2 weeks later through a mail survey); patient-centred care, assessed with the Patient Perception of Patient-Centredness instrument; patient activation, assessed with the Patient Activation Measure; and patient enablement, assessed with the Patient Enablement Instrument. Results The internal consistency of the 6 subscales of the PESQ was adequate (Cronbach α = .69 to .92). The test-retest reliability was very good (r = 0.90; 95% CI 0.84 to 0.93). Concurrent validity with the Patient Perception of Patient-Centredness instrument was good (r = −0.67; 95% CI −0.78 to −0.53; P < .001). The PESQ accounts for 11% of the total variance with the Patient Activation Measure (r2 = 0.11; P = .002) and 19% of the variance with the Patient Enablement Instrument (r2 = 0.19; P < .001). Conclusion The newly developed PESQ presents good psychometric properties, allowing for its use in practice and research. PMID:26889507

  1. Dust control for Enabler

    NASA Technical Reports Server (NTRS)

    Hilton, Kevin; Karl, Chad; Litherland, Mark; Ritchie, David; Sun, Nancy

    1992-01-01

    The dust control group designed a system to restrict dust that is disturbed by the Enabler during its operation from interfering with astronaut or camera visibility. This design also considers the many different wheel positions made possible through the use of artinuation joints that provide the steering and wheel pitching for the Enabler. The system uses a combination of brushes and fenders to restrict the dust when the vehicle is moving in either direction and in a turn. This design also allows for each of maintenance as well as accessibility of the remainder of the vehicle.

  2. Dust control for Enabler

    NASA Technical Reports Server (NTRS)

    Hilton, Kevin; Karl, Chad; Litherland, Mark; Ritchie, David; Sun, Nancy

    1992-01-01

    The dust control group designed a system to restrict dust that is disturbed by the Enabler during its operation from interfering with astronaut or camera visibility. This design also considers the many different wheel positions made possible through the use of artinuation joints that provide the steering and wheel pitching for the Enabler. The system uses a combination of brushes and fenders to restrict the dust when the vehicle is moving in either direction and in a turn. This design also allows for ease of maintenance as well as accessibility of the remainder of the vehicle.

  3. Bespoke contrast-matched diblock copolymer nanoparticles enable the rational design of highly transparent Pickering double emulsions† †Electronic supplementary information (ESI) available: GPC chromatograms, additional transmission electron micrographs, digital photographs, visible absorption spectra and laser diffraction data, further optical and fluorescence micrographs. See DOI: 10.1039/c6nr03856e Click here for additional data file.

    PubMed Central

    Thompson, Kate L.; Derry, Matthew J.; Warren, Nicholas J.; Ratcliffe, Liam P. D.; Williams, Clive N.; Brown, Steven L.

    2016-01-01

    We report the preparation of highly transparent oil-in-water Pickering emulsions using contrast-matched organic nanoparticles. This is achieved via addition of judicious amounts of either sucrose or glycerol to an aqueous dispersion of poly(glycerol monomethacrylate)56–poly(2,2,2-trifluoroethyl methacrylate)500 [PGMA–PTFEMA] diblock copolymer nanoparticles prior to high shear homogenization with an equal volume of n-dodecane. The resulting Pickering emulsions comprise polydisperse n-dodecane droplets of 20–100 μm diameter and exhibit up to 96% transmittance across the visible spectrum. In contrast, control experiments using non-contrast-matched poly(glycerol monomethacrylate)56–poly(benzyl methacrylate)300 [PGMA56–PBzMA300] diblock copolymer nanoparticles as a Pickering emulsifier only produced conventional highly turbid emulsions. Thus contrast-matching of the two immiscible phases is a necessary but not sufficient condition for the preparation of highly transparent Pickering emulsions: it is essential to use isorefractive nanoparticles in order to minimize light scattering. Furthermore, highly transparent oil-in-water-in-oil Pickering double emulsions can be obtained by homogenizing the contrast-matched oil-in-water Pickering emulsion prepared using the PGMA56–PTFEMA500 nanoparticles with a contrast-matched dispersion of hydrophobic poly(lauryl methacrylate)39–poly(2,2,2-trifluoroethyl methacrylate)800 [PLMA39–PTFEMA800] diblock copolymer nanoparticles in n-dodecane. Finally, we show that an isorefractive oil-in-water Pickering emulsion enables fluorescence spectroscopy to be used to monitor the transport of water-insoluble small molecules (pyrene and benzophenone) between n-dodecane droplets. Such transport is significantly less efficient than that observed for the equivalent isorefractive surfactant-stabilized emulsion. Conventional turbid emulsions do not enable such a comparison to be made because the intense light scattering leads to

  4. Dim light at night does not disrupt timing or quality of sleep in mice.

    PubMed

    Borniger, Jeremy C; Weil, Zachary M; Zhang, Ning; Nelson, Randy J

    2013-10-01

    Artificial nighttime illumination has recently become commonplace throughout the world; however, in common with other animals, humans have not evolved in the ecological context of chronic light at night. With prevailing evidence linking the circadian, endocrine, immune, and metabolic systems, understanding these relationships is important to understanding the etiology and progression of several diseases. To eliminate the covariate of sleep disruption in light at night studies, researchers often use nocturnal animals. However, the assumption that light at night does not affect sleep in nocturnal animals remains unspecified. To test the effects of light at night on sleep, we maintained Swiss-Webster mice in standard light/dark (LD) or dim light at night (DLAN) conditions for 8-10 wks and then measured electroencephalogram (EEG) and electromyogram (EMG) biopotentials via wireless telemetry over the course of two consecutive days to determine differences in sleep timing and homeostasis. Results show no statistical differences in total percent time, number of episodes, maximum or average episode durations in wake, slow-wave sleep (SWS), or rapid eye movement (REM) sleep. No differences were evident in SWS delta power, an index of sleep drive, between groups. Mice kept in DLAN conditions showed a relative increase in REM sleep during the first few hours after the dark/light transition. Both groups displayed normal 24-h circadian rhythms as measured by voluntary running wheel activity. Groups did not differ in body mass, but a marked negative correlation of body mass with percent time spent awake and a positive correlation of body mass with time spent in SWS was evident. Elevated body mass was also associated with shorter maximum wake episode durations, indicating heavier animals had more trouble remaining in the wake vigilance state for extended periods of time. Body mass did not correlate with activity levels, nor did activity levels correlate with time spent in

  5. Microsystems Enabled Photovoltaics

    SciTech Connect

    Gupta, Vipin; Nielson, Greg; Okandan, Murat, Granata, Jennifer; Nelson, Jeff; Haney, Mike; Cruz-Campa, Jose Luiz

    2012-07-02

    Sandia's microsystems enabled photovoltaic advances combine mature technology and tools currently used in microsystem production with groundbreaking advances in photovoltaics cell design, decreasing production and system costs while improving energy conversion efficiency. The technology has potential applications in buildings, houses, clothing, portable electronics, vehicles, and other contoured structures.

  6. Microsystems Enabled Photovoltaics

    ScienceCinema

    Gupta, Vipin; Nielson, Greg; Okandan, Murat, Granata, Jennifer; Nelson, Jeff; Haney, Mike; Cruz-Campa, Jose Luiz

    2016-07-12

    Sandia's microsystems enabled photovoltaic advances combine mature technology and tools currently used in microsystem production with groundbreaking advances in photovoltaics cell design, decreasing production and system costs while improving energy conversion efficiency. The technology has potential applications in buildings, houses, clothing, portable electronics, vehicles, and other contoured structures.

  7. Life of fluorescent lamps operated at high frequencies with solid-state ballasts

    NASA Astrophysics Data System (ADS)

    Verderber, R. R.; Morse, O.; Rubinstein, F. M.

    1985-07-01

    Standard 40-watt, F-40, rapid-start, fluorescent lamps were operated with solid-state ballasts following the standard life-testing cycle of 3 hours on and 20 minutes off for more than 20,000 hours at high frequency. Lamp operating characteristics (starting voltage, filament voltage, arc current, and current-crest factor) were studied as factors affecting lamp life. Measurements show that fluorescent lamps can attain rated life at high frequency using solid-state ballasts. When lamps are operated in the dimmed mode, full filament power is required to sustain lamplife. The rate of lamp lumen depreciation is dependent on the lamp loading and not the operating frequency.

  8. How bright planets became dim stars: planetary speculations in John Herschel's double star astronomy.

    PubMed

    Case, Stephen

    2014-03-01

    Previous research on the origins of double star astronomy in the early nineteenth century emphasized the role mathematical methods and instrumentation played in motivating early observations of these objects. The work of the British astronomer John Herschel, however, shows that questions regarding the physical nature of double stars were also important. In particular, an analysis of John Herschel's early work on double stars illustrates the way in which speculations regarding these objects were shaped by assumptions of the properties of stars themselves. For Herschel, a major consideration in double star astronomy was distinguishing between types of double stars. Optical doubles were useful in determining parallax while binary doubles were not. In practice, classification of a specific double star pair into one of these categories was based on the assumption that stars were of approximately the same luminosity and thus differences in relative brightness between stars were caused by difference in distances. Such assumptions, though ultimately abandoned, would lead Herschel in the 1830s to advance the possibility that the dim companion stars in certain double star pairs were not stars at all but in fact planets.

  9. Annual parallax and a dimming event of a Mira variable star, FV Bootis

    NASA Astrophysics Data System (ADS)

    Kamezaki, Tatsuya; Nakagawa, Akiharu; Omodaka, Toshihiro; Inoue, Kan-ichiro; Chibueze, James O.; Nagayama, Takumi; Ueno, Yuji; Matsunaga, Noriyuki

    2016-10-01

    We present the first measurement of the trigonometric parallax of water masers associated with a Mira star, FV Bootis (FV Boo) using VLBI Exploration of Radio Astrometry (VERA). Based on our multi-epoch VERA observations, we derived the parallax to be 0.97 ± 0.06 mas, which corresponds to a distance of 1.03^{+0.07}_{-0.06} kpc. The water masers around FV Boo were spatially distributed over an area of 41 au × 41 au, and their internal motions indicate the presence of an outflow. Using the Kagoshima University 1 m optical/infrared telescope, we determined the period to be 305.6 d and the mean apparent magnitude to be +2.91 mag in the K'-band. On the period-luminosity plane, the obtained period and K'-band magnitude puts FV Boo slightly below the sequence of Miras, possibly due to circumstellar reddening. Combining our photometric data with COBE and 2MASS datasets spanning over 20 years, we found in the near infrared that FV Boo was significantly fainter in 2005 compared with preceding and later phases. Its color, however, did not show a large variation through this change. We infer that the dimming could be caused by an eclipse due to a cloud in a binary system.

  10. Multiple Episodes of Convergence in Genes of the Dim Light Vision Pathway in Bats

    PubMed Central

    Shen, Yong-Yi; Lim, Burton K.; Liu, He-Qun; Liu, Jie; Irwin, David M.; Zhang, Ya-Ping

    2012-01-01

    The molecular basis of the evolution of phenotypic characters is very complex and is poorly understood with few examples documenting the roles of multiple genes. Considering that a single gene cannot fully explain the convergence of phenotypic characters, we choose to study the convergent evolution of rod vision in two divergent bats from a network perspective. The Old World fruit bats (Pteropodidae) are non-echolocating and have binocular vision, whereas the sheath-tailed bats (Emballonuridae) are echolocating and have monocular vision; however, they both have relatively large eyes and rely more on rod vision to find food and navigate in the night. We found that the genes CRX, which plays an essential role in the differentiation of photoreceptor cells, SAG, which is involved in the desensitization of the photoactivated transduction cascade, and the photoreceptor gene RH, which is directly responsible for the perception of dim light, have undergone parallel sequence evolution in two divergent lineages of bats with larger eyes (Pteropodidae and Emballonuroidea). The multiple convergent events in the network of genes essential for rod vision is a rare phenomenon that illustrates the importance of investigating pathways and networks in the evolution of the molecular basis of phenotypic convergence. PMID:22509324

  11. Chronic exposure to dim light at night suppresses immune responses in Siberian hamsters.

    PubMed

    Bedrosian, Tracy A; Fonken, Laura K; Walton, James C; Nelson, Randy J

    2011-06-23

    Species have been adapted to specific niches optimizing survival and reproduction; however, urbanization by humans has dramatically altered natural habitats. Artificial light at night (LAN), termed 'light pollution', is an often overlooked, yet increasing disruptor of habitats, which perturbs physiological processes that rely on precise light information. For example, LAN alters the timing of reproduction and activity in some species, which decreases the odds of successful breeding and increases the threat of predation for these individuals, leading to reduced fitness. LAN also suppresses immune function, an important proxy for survival. To investigate the impact of LAN in a species naive to light pollution in its native habitat, immune function was examined in Siberian hamsters derived from wild-caught stock. After four weeks exposure to dim LAN, immune responses to three different challenges were assessed: (i) delayed-type hypersensitivity (DTH), (ii) lipopolysaccharide-induced fever, and (iii) bactericide activity of blood. LAN suppressed DTH response and reduced bactericide activity of blood after lipopolysaccharide treatment, in addition to altering daily patterns of locomotor activity, suggesting that human encroachment on habitats via night-time lighting may inadvertently compromise immune function and ultimately fitness.

  12. Body size limits dim-light foraging activity in stingless bees (Apidae: Meliponini).

    PubMed

    Streinzer, Martin; Huber, Werner; Spaethe, Johannes

    2016-10-01

    Stingless bees constitute a species-rich tribe of tropical and subtropical eusocial Apidae that act as important pollinators for flowering plants. Many foraging tasks rely on vision, e.g. spatial orientation and detection of food sources and nest entrances. Meliponini workers are usually small, which sets limits on eye morphology and thus quality of vision. Limitations are expected both on acuity, and thus on the ability to detect objects from a distance, as well as on sensitivity, and thus on the foraging time window at dusk and dawn. In this study, we determined light intensity thresholds for flight under dim light conditions in eight stingless bee species in relation to body size in a Neotropical lowland rainforest. Species varied in body size (0.8-1.7 mm thorax-width), and we found a strong negative correlation with light intensity thresholds (0.1-79 lx). Further, we measured eye size, ocelli diameter, ommatidia number, and facet diameter. All parameters significantly correlated with body size. A disproportionately low light intensity threshold in the minute Trigonisca pipioli, together with a large eye parameter P eye suggests specific adaptations to circumvent the optical constraints imposed by the small body size. We discuss the implications of body size in bees on foraging behavior. PMID:27495990

  13. Surface dimming by the 2013 Rim Fire simulated by a sectional aerosol model

    NASA Astrophysics Data System (ADS)

    Yu, Pengfei; Toon, Owen B.; Bardeen, Charles G.; Bucholtz, Anthony; Rosenlof, Karen H.; Saide, Pablo E.; Da Silva, Arlindo; Ziemba, Luke D.; Thornhill, Kenneth L.; Jimenez, Jose-Luis; Campuzano-Jost, Pedro; Schwarz, Joshua P.; Perring, Anne E.; Froyd, Karl D.; Wagner, N. L.; Mills, Michael J.; Reid, Jeffrey S.

    2016-06-01

    The Rim Fire of 2013, the third largest area burned by fire recorded in California history, is simulated by a climate model coupled with a size-resolved aerosol model. Modeled aerosol mass, number, and particle size distribution are within variability of data obtained from multiple-airborne in situ measurements. Simulations suggest that Rim Fire smoke may block 4-6% of sunlight energy reaching the surface, with a dimming efficiency around 120-150 W m-2 per unit aerosol optical depth in the midvisible at 13:00-15:00 local time. Underestimation of simulated smoke single scattering albedo at midvisible by 0.04 suggests that the model overestimates either the particle size or the absorption due to black carbon. This study shows that exceptional events like the 2013 Rim Fire can be simulated by a climate model with 1° resolution with overall good skill, although that resolution is still not sufficient to resolve the smoke peak near the source region.

  14. Physiology and morphology of sustaining and dimming neurons of the crab Chasmagnathus granulatus (Brachyura: Grapsidae).

    PubMed

    Berón de Astrada, Martín; Tuthill, John C; Tomsic, Daniel

    2009-08-01

    In crustaceans, sustaining (SN) and dimming (DN) neurons are readily identified by their distinct responses to a light pulse. However, morphological identification and electrophysiological characterization of these neurons has been achieved only in the crayfish. This study provides a description of SNs and DNs in a second crustacean species, the crab Chasmagnathus. SNs and DNs of the crab arborize extensively in the medulla and the axons project to the midbrain. Upon a light pulse, SNs depolarize and increase the firing rate while DNs hyperpolarize and reduce firing. These responses are highly consistent and their magnitudes depend on the intensity of the light pulse. When stimulated with a wide-field motion grating, SNs respond with a modulation of the membrane potential and spike frequency. We also characterized the responses of these neurons to a rotating e-vector of polarized light. SNs show the maximum depolarization when the e-vector approaches vertical. In contrast, DNs show maximal depolarization to near horizontal e-vector orientations. The semi-terrestrial crab and the crayfish inhabit unique light environments and exhibit disparate visual behaviors. Yet, we found that the location, morphology and physiology of SNs and DNs of the crab are nearly identical to those described in the crayfish.

  15. Annual parallax and a dimming event of a Mira variable star, FV Bootis

    NASA Astrophysics Data System (ADS)

    Kamezaki, Tatsuya; Nakagawa, Akiharu; Omodaka, Toshihiro; Inoue, Kan-ichiro; Chibueze, James O.; Nagayama, Takumi; Ueno, Yuji; Matsunaga, Noriyuki

    2016-08-01

    We present the first measurement of the trigonometric parallax of water masers associated with a Mira star, FV Bootis (FV Boo) using VLBI Exploration of Radio Astrometry (VERA). Based on our multi-epoch VERA observations, we derived the parallax to be 0.97 ± 0.06 mas, which corresponds to a distance of 1.03^{+0.07}_{-0.06} kpc. The water masers around FV Boo were spatially distributed over an area of 41 au × 41 au, and their internal motions indicate the presence of an outflow. Using the Kagoshima University 1 m optical/infrared telescope, we determined the period to be 305.6 d and the mean apparent magnitude to be +2.91 mag in the K'-band. On the period-luminosity plane, the obtained period and K'-band magnitude puts FV Boo slightly below the sequence of Miras, possibly due to circumstellar reddening. Combining our photometric data with COBE and 2MASS datasets spanning over 20 years, we found in the near infrared that FV Boo was significantly fainter in 2005 compared with preceding and later phases. Its color, however, did not show a large variation through this change. We infer that the dimming could be caused by an eclipse due to a cloud in a binary system.

  16. The application of IR detector with windowing technique in the small and dim target detection

    NASA Astrophysics Data System (ADS)

    Su, Xiaofeng; Chen, Fansheng; Dong, Yucui; Cui, Kun; Huang, Sijie

    2015-04-01

    The performance of small and dim IR target detection is mostly affected by the signal to noise ratio(SNR) and signal to clutter ratio(SCR), for the MWIR especially LWIR array detector, because of the background radiation and the optical system radiation, the SCR cannot be unlimited increased by using a longer integral time, so the frame rate of the detector was mainly limited by the data readout time especially in a large-scale infrared detector, in this paper a new MWIR array detector with windowing technique was used to do the experiment, which can get a faster frame rate around the target by using the windowing mode, so the redundant information could be ignore, and the background subtraction was used to remove the fixed pattern noise and adjust the dynamic range of the target, then a local NUC(non uniformity correction) technique was proposed to improve the SCR of the target, the advantage between local NUC and global NUC was analyzed in detail, finally the multi local window frame accumulation was adopted to enhance the target further, and the SNR of the target was improved. The experiment showed the SCR of the target can improved from 1.3 to 36 at 30 frames accumulation, which make the target detection and tracking become very easily by using the new method.

  17. Home dim light melatonin onsets with measures of compliance in delayed sleep phase disorder.

    PubMed

    Burgess, Helen J; Park, Margaret; Wyatt, James K; Fogg, Louis F

    2016-06-01

    The dim light melatonin onset (DLMO) assists with the diagnosis and treatment of circadian rhythm sleep disorders. Home DLMOs are attractive for cost savings and convenience, but can be confounded by home lighting and sample timing errors. We developed a home saliva collection kit with objective measures of light exposure and sample timing. We report on our first test of the kit in a clinical population. Thirty-two participants with delayed sleep phase disorder (DSPD; 17 women, aged 18-52 years) participated in two back-to-back home and laboratory phase assessments. Most participants (66%) received at least one 30-s epoch of light >50 lux during the home phase assessments, but for only 1.5% of the time. Most participants (56%) collected every saliva sample within 5 min of the scheduled time. Eighty-three per cent of home DLMOs were not affected by light or sampling errors. The home DLMOs occurred, on average, 10.2 min before the laboratory DLMOs, and were correlated highly with the laboratory DLMOs (r = 0.93, P < 0.001). These results indicate that home saliva sampling with objective measures of light exposure and sample timing, can assist in identifying accurate home DLMOs.

  18. Flares from a candidate Galactic magnetar suggest a missing link to dim isolated neutron stars.

    PubMed

    Castro-Tirado, A J; de Ugarte Postigo, A; Gorosabel, J; Jelínek, M; Fatkhullin, T A; Sokolov, V V; Ferrero, P; Kann, D A; Klose, S; Sluse, D; Bremer, M; Winters, J M; Nuernberger, D; Pérez-Ramírez, D; Guerrero, M A; French, J; Melady, G; Hanlon, L; McBreen, B; Leventis, K; Markoff, S B; Leon, S; Kraus, A; Aceituno, F J; Cunniffe, R; Kubánek, P; Vítek, S; Schulze, S; Wilson, A C; Hudec, R; Durant, M; González-Pérez, J M; Shahbaz, T; Guziy, S; Pandey, S B; Pavlenko, L; Sonbas, E; Trushkin, S A; Bursov, N N; Nizhelskij, N A; Sánchez-Fernández, C; Sabau-Graziati, L

    2008-09-25

    Magnetars are young neutron stars with very strong magnetic fields of the order of 10(14)-10(15) G. They are detected in our Galaxy either as soft gamma-ray repeaters or anomalous X-ray pulsars. Soft gamma-ray repeaters are a rare type of gamma-ray transient sources that are occasionally detected as bursters in the high-energy sky. No optical counterpart to the gamma-ray flares or the quiescent source has yet been identified. Here we report multi-wavelength observations of a puzzling source, SWIFT J195509+261406. We detected more than 40 flaring episodes in the optical band over a time span of three days, and a faint infrared flare 11 days later, after which the source returned to quiescence. Our radio observations confirm a Galactic nature and establish a lower distance limit of approximately 3.7 kpc. We suggest that SWIFT J195509+261406 could be an isolated magnetar whose bursting activity has been detected at optical wavelengths, and for which the long-term X-ray emission is short-lived. In this case, a new manifestation of magnetar activity has been recorded and we can consider SWIFT J195509+261406 to be a link between the 'persistent' soft gamma-ray repeaters/anomalous X-ray pulsars and dim isolated neutron stars.

  19. Dim light at night disturbs the daily sleep-wake cycle in the rat

    PubMed Central

    Jan Stenvers, Dirk; van Dorp, Rick; Foppen, Ewout; Mendoza, Jorge; Opperhuizen, Anne-Loes; Fliers, Eric; Bisschop, Peter H.; Meijer, Johanna H.; Kalsbeek, Andries; Deboer, Tom

    2016-01-01

    Exposure to light at night (LAN) is associated with insomnia in humans. Light provides the main input to the master clock in the hypothalamic suprachiasmatic nucleus (SCN) that coordinates the sleep-wake cycle. We aimed to develop a rodent model for the effects of LAN on sleep. Therefore, we exposed male Wistar rats to either a 12 h light (150–200lux):12 h dark (LD) schedule or a 12 h light (150–200 lux):12 h dim white light (5 lux) (LDim) schedule. LDim acutely decreased the amplitude of daily rhythms of REM and NREM sleep, with a further decrease over the following days. LDim diminished the rhythms of 1) the circadian 16–19 Hz frequency domain within the NREM sleep EEG, and 2) SCN clock gene expression. LDim also induced internal desynchronization in locomotor activity by introducing a free running rhythm with a period of ~25 h next to the entrained 24 h rhythm. LDim did not affect body weight or glucose tolerance. In conclusion, we introduce the first rodent model for disturbed circadian control of sleep due to LAN. We show that internal desynchronization is possible in a 24 h L:D cycle which suggests that a similar desynchronization may explain the association between LAN and human insomnia. PMID:27762290

  20. Body size limits dim-light foraging activity in stingless bees (Apidae: Meliponini).

    PubMed

    Streinzer, Martin; Huber, Werner; Spaethe, Johannes

    2016-10-01

    Stingless bees constitute a species-rich tribe of tropical and subtropical eusocial Apidae that act as important pollinators for flowering plants. Many foraging tasks rely on vision, e.g. spatial orientation and detection of food sources and nest entrances. Meliponini workers are usually small, which sets limits on eye morphology and thus quality of vision. Limitations are expected both on acuity, and thus on the ability to detect objects from a distance, as well as on sensitivity, and thus on the foraging time window at dusk and dawn. In this study, we determined light intensity thresholds for flight under dim light conditions in eight stingless bee species in relation to body size in a Neotropical lowland rainforest. Species varied in body size (0.8-1.7 mm thorax-width), and we found a strong negative correlation with light intensity thresholds (0.1-79 lx). Further, we measured eye size, ocelli diameter, ommatidia number, and facet diameter. All parameters significantly correlated with body size. A disproportionately low light intensity threshold in the minute Trigonisca pipioli, together with a large eye parameter P eye suggests specific adaptations to circumvent the optical constraints imposed by the small body size. We discuss the implications of body size in bees on foraging behavior.

  1. Immunohistochemical distribution of phosphatidylglucoside using anti-phosphatidylglucoside monoclonal antibody (DIM21)

    SciTech Connect

    Kitamura, Yukisato Okazaki, Toshiro; Nagatsuka, Yasuko; Hirabayashi, Yoshio; Kato, Shinsuke; Hayashi, Kazuhiko

    2007-10-19

    The immunohistochemical distribution of phosphatidylglucoside (PhGlc) in organs obtained from human autopsy cases was investigated using the DIM21 antibody. Immunohistochemical staining was performed on formaline-fixed, paraffin-embedded sections using the simple stain peroxidase method. The sections were then subjected to antigen retrieval by microwave irradiation in citrate buffer. PhGlc expression was observed in not only the epithelial but also the non-epithelial components of several visceral organs. Squamous and glandular epithelial cells were positive for PhGlc in several organs. The surface areas of the epithelium, particularly the squamous epithelium, were positive. Mesothelial cells were also positive in some organs. Endothelial cells, polymorphonuclear (PMN) cells are positive in several organs. Macrophage is positive in many organs. Epithelial cells of the gallbladder were positive, however, the intrahepatic bile ducts were not positive. In the brain tissue, astroglial cells, the chorioide plexus, the pituitary gland, and ependymal cells were positive. Further investigation is indispensable in order to establish a relationship between cell differentiation and PhGlc expression.

  2. How bright planets became dim stars: planetary speculations in John Herschel's double star astronomy.

    PubMed

    Case, Stephen

    2014-03-01

    Previous research on the origins of double star astronomy in the early nineteenth century emphasized the role mathematical methods and instrumentation played in motivating early observations of these objects. The work of the British astronomer John Herschel, however, shows that questions regarding the physical nature of double stars were also important. In particular, an analysis of John Herschel's early work on double stars illustrates the way in which speculations regarding these objects were shaped by assumptions of the properties of stars themselves. For Herschel, a major consideration in double star astronomy was distinguishing between types of double stars. Optical doubles were useful in determining parallax while binary doubles were not. In practice, classification of a specific double star pair into one of these categories was based on the assumption that stars were of approximately the same luminosity and thus differences in relative brightness between stars were caused by difference in distances. Such assumptions, though ultimately abandoned, would lead Herschel in the 1830s to advance the possibility that the dim companion stars in certain double star pairs were not stars at all but in fact planets. PMID:24508199

  3. Spectral Changes in Metal Halide and High-Pressure Sodium Lamps Equipped with Electronic Dimming

    NASA Technical Reports Server (NTRS)

    Bubenheim, David L.; Sargis, Raman; Wilson, David

    1995-01-01

    Electronic dimming of high-intensity discharge lamps offers control of Photosynthetic Photon Flux (PPF) but is often characterized as causing significant spectral changes. Growth chambers with 400-W Metal Halide (MH) and High-Pressure Sodium (HPS) lamps were equipped with a dimmer system using Silicon-Controlled Rectifiers (SCR) as high-speed switches. Phase control operation turned the line power off for some period of the alternating current cycle. At full power, the electrical input to HPS and MH lamps was 480 W (root mean squared) and could be decreased to 267 W and 428 W, respectively, before the arc was extinguished. Concomitant with this decrease in input power, PPF decreased by 60% in HPS and 50% in MH. The HPS lamp has characteristic spectral peaks at 589 and 595 nm. As power to the HPS lamps was decreased, the 589-nm peak remained constant while the 595-nm peak decreased, equaling the 589-nm peak at 345-W input, and 589-nm peak was almost absent at 270-W input. The MH lamp has a broader spectral output but also has a peak at 589 nm and another smaller peak at 545 nm. As input power approached 428 W, the 589-nm peak shifted to 570 nm. While the spectrum changed as input power was decreased in the MH and HPS lamps, the phytochrome equilibrium ratio (P(sub ft):P(sub tot)) remains unchanged for both lamp types.

  4. Coronal Outflow Velocities in a 3D Coronal Model Determined from UVCS Doppler Dimming Observations

    NASA Astrophysics Data System (ADS)

    Strachan, L.; Panasyuk, A. V.; Dobrzycka, D.; Gibson, S.; Biesecker, D. A.; Ko, Y.-K.; Galvin, A. B.; Romoli, M.; Kohn, J. L.

    1998-04-01

    We constrain coronal outflow velocity solutions, resolved along the line-of-sight, by using Doppler dimming models of H I Lyman alpha and O VI 1032/1037 Angstrom emissivities obtained with data from the Ultraviolet Coronagraph Spectrometer (UVCS) on SOHO. The local emissivities, from heliocentric heights of 1.5 to 3.0 radii, were determined from 3-D reconstructions of line-of-sight intensities obtained during the Whole Sun Month Campaign (10 Aug. -- 8 Sep. 1996). The models use electron densities derived from polarized brightness measurements made with the visible light coronagraphs on UVCS and LASCO, supplemented with data from Mark III at NCAR/MLSO. Electron temperature profiles are derived from `freezing-in' temperatures obtained from an analysis of charge state data from SWICS/Ulysses. The work concentrates on O5+ outflow velocities which are determined from an analysis of the the O VI line ratios. This analysis is less sensitive to the uncertainties in the electron density and independent of the ionization balance and elemental abundance than the analyses which use individual spectral lines. This work is supported in part by NASA under grant NAG-3192 to the Smithsonian Astrophysical Observatory, by the Italian Space Agency and by Swiss funding agencies.

  5. CD34+/CD45-dim stem cell mobilization by hyperbaric oxygen - changes with oxygen dosage.

    PubMed

    Heyboer, Marvin; Milovanova, Tatyana N; Wojcik, Susan; Grant, William; Chin, Mary; Hardy, Kevin R; Lambert, David S; Logue, Christopher; Thom, Stephen R

    2014-05-01

    Because hyperbaric oxygen treatment mobilizes bone marrow derived-stem/progenitor cells by a free radical mediated mechanism, we hypothesized that there may be differences in mobilization efficiency based on exposure to different oxygen partial pressures. Blood from twenty consecutive patients was obtained before and after the 1st, 10th and 20th treatment at two clinical centers using protocols involving exposures to oxygen at either 2.0 or 2.5 atmospheres absolute (ATA). Post-treatment values of CD34+, CD45-dim leukocytes were always 2-fold greater than the pre-treatment values for both protocols. Values for those treated at 2.5 ATA were significantly greater than those treated at 2.0 ATA by factors of 1.9 to 3-fold after the 10th and before and after the 20th treatments. Intracellular content of hypoxia inducible factors -1, -2, and -3, thioredoxin-1 and poly-ADP-ribose polymerase assessed in permeabilized CD34+ cells with fluorophore-conjugated antibodies were twice as high in all post- versus pre-treatment samples with no significant differences between 2.0 and 2.5 ATA protocols. We conclude that putative progenitor cell mobilization is higher with 2.5 versus 2.0 ATA treatments, and all newly mobilized cells exhibit higher concentrations of an array of regulatory proteins.

  6. Exploring the World of Fluorescence.

    ERIC Educational Resources Information Center

    Czarnik, Stanley A.

    1991-01-01

    Provides a basic introduction to fluorescence enabling the amateur scientist to easily, and safely, demonstrate and photograph this phenomenon with the aid of an ultraviolet lamp. Includes a list of necessary equipment and materials, as well as catalog availability from several hardware suppliers. (JJK)

  7. Evaluation of CD56dim and CD56bright natural killer cells in peripheral blood of women with IVF failures

    PubMed Central

    Mardanian, Farahnaz; Kazeroonizadeh, Moones; Rashidi, Bahman

    2015-01-01

    Background: Infertility is an increasing medical and social problem. In vitro fertilization (IVF) has become a common and accessible treatment for a wide variety of indications that have variable outcomes. Natural killer (NK) cells have been identified as relevant immunological factors involved in reproductive success or failure. Objective: The aim of this study was to compare the percentage of peripheral blood CD56+ (CD56dim and CD56bright) cells and the level of NK cell in patients with IVF failure with those of successful IVF control women. Materials and Methods: We assessed the level of CD56dim CD16+ and CD56bright CD16- cells in 50 women under IVF treatment and compared between successful IVF and IVF failure with the flowcytometry technique. Results: Of studied women, 68% did not response to IVF therapy and 32% had successful IVF, the level of CD56dim CD16+ cells in women with IVF failure was significantly higher than successful IVF (p<0.0001) but the level of CD56bright CD16- cells was not significantly different between women with IVF failure and successful IVF (p=0.28). Conclusion: The results of present study demonstrated that the level of NK cells as a risk factor is associated with pregnancy loss in women with IVF failure. However, number of sample in this study is low and further studies with more sample size are needed to be done. We suggest considering treatment option for women undergoing repeated IVF failure with increased percentage of CD56dim cells and the level of peripheral blood NK cell. PMID:26568763

  8. Fluorescent refrigeration

    DOEpatents

    Epstein, R.I.; Edwards, B.C.; Buchwald, M.I.; Gosnell, T.R.

    1995-09-05

    Fluorescent refrigeration is based on selective radiative pumping, using substantially monochromatic radiation, of quantum excitations which are then endothermically redistributed to higher energies. Ultimately, the populated energy levels radiatively deexcite emitting, on the average, more radiant energy than was initially absorbed. The material utilized to accomplish the cooling must have dimensions such that the exciting radiation is strongly absorbed, but the fluorescence may exit the material through a significantly smaller optical pathlength. Optical fibers and mirrored glasses and crystals provide this requirement. 6 figs.

  9. Enabling Wind Power Nationwide

    SciTech Connect

    Jose, Zayas; Michael, Derby; Patrick, Gilman; Ananthan, Shreyas; Lantz, Eric; Cotrell, Jason; Beck, Fredic; Tusing, Richard

    2015-05-01

    Leveraging this experience, the U.S. Department of Energy’s (DOE’s) Wind and Water Power Technologies Office has evaluated the potential for wind power to generate electricity in all 50 states. This report analyzes and quantifies the geographic expansion that could be enabled by accessing higher above ground heights for wind turbines and considers the means by which this new potential could be responsibly developed.

  10. Dim star fringe stabilization demonstration using pathlength feed-forward on the SIM testbed 3 (STB3)

    NASA Astrophysics Data System (ADS)

    Goullioud, Renaud; Alvarez-Salazar, Oscar S.; Nemati, Bijan

    2003-02-01

    Future space-based optical interferometers such as the Space Interferometer Mission require fringe stabilization to the level of nanometers in order to produce astrometric data at the micro-arc-second level. Even the best attitude control system available to date will not be able to stabilize the attitude of a several thousand pound spacecraft to a few milli-arc-seconds. Active pathlength control is usually implemented to compensate for attitude drift of the spacecraft. This issue has been addressed in previous experiments while tracking bright stars. In the case of dim stars, as the sensor bandwidth falls below one hertz, feedback control will not provide sufficient rejection. However, stabilization of the fringes from a dim-star down to the nanometer level can be done open loop using information from additional interferometers looking at bright guide stars. The STB3 testbed developed at the Jet Propulsion Laboratory features three optical interferometers sharing a common baseline, dynamically representative to the SIM interferometer. An artificial star feeding the interferometers is installed on a separate optics bench. Voice coils are used to simulate the attitude motion of the spacecraft by moving the entire bench. Data measured on STB3 show that fringe motion of a dim star due to spacecraft attitude changes can be attenuated by 80 dB at 0.1Hz without feedback control, using only information from two guide stars. This paper describes the STB3 setup, the pathlength feed-forward architecture, implementation issues and data collected with the system.

  11. Safety and tolerability of DIM-based therapy designed as personalized approach to reverse prostatic intraepithelial neoplasia (PIN)

    PubMed Central

    2014-01-01

    Background It has been shown previously that novel formulation of 3,3'-diindolylmethane (DIM) substance with high bioavailability (Infemin) inhibits tumor development due to the tumor growth rate reduction in the xenograft model of prostate cancer. Prostatic intraepithelial neoplasia (PIN) is considered to be promising as a personalized and preventive treatment strategy of prostate cancer (PC). We assessed the safety of Infemin in men with PIN and discussed the interim results. Materials and methods A total of 14 patients with PIN were enrolled. They were randomized to 900 mg DIM or placebo daily for 3 months. Safety was evaluated by adverse events (AEs), laboratory tests and physical examinations. Results and conclusion The trial revealed that Infemin treatment is associated with minimal toxicity and no serious adverse events when administered orally for 3 months. We noted three adverse events including nausea and diarrhea in two patients (14%). Combined 95% confidence interval (CI) was 1.8%–42.8%. Therapy was continued in all cases of adverse events. Good tolerability of DIM-based formulation allows us to recommend it for further clinical trials among men diagnosed with PIN for its efficacy and long-term safety parameters. PMID:25309637

  12. Disorganized muscle protein-1 (DIM-1) of filarial parasite Brugia malayi: cDNA cloning, expression, purification, structural modeling and its potential as vaccine candidate for human filarial infection.

    PubMed

    Kushwaha, Vikas; Kumar, Vikash; Verma, Shiv K; Sharma, Rolee; Siddiqi, M I; Murthy, P K

    2014-03-26

    We have recently identified disorganized muscle protein-1 (DIM-1) in one of the proinflammatory fractions of the human filaria Brugia malayi adult worm. The present study was undertaken to characterize B. malayi DIM-1 (DIM-1bm) and explore its vaccine potential. In this study we cloned and expressed the DIM-1bm gene, investigated its sequence homology with other nematodes, constructed in silico structural model, purified the recombinant DIM-1bm (rDIM-1bm) protein, and studied the effect of immunization with rDIM-1bm on the establishment of B. malayi infection in Mastomys coucha. DIM-1bm showed similarity with DIM-1 of Caenorhabditis elegans, Ascaris suum and Loa loa. Structural modeling revealed three immunoglobulin domains in DIM-1bm indicating that it is a member of immunoglobulin superfamily (IgSF) and 'blastn' results showed that DIM-1bm coding sequence (CDS) have almost no homology with human and mouse nucleotide sequences. Immunization with rDIM-1bm partially protected M. coucha against establishment of infection as inferred by a low recovery of microfilariae (37-64%) and parasite burden (∼50%). The enhanced activity of macrophages, and IFN-γ and NO responses, and elevated levels of specific IgG, IgG1, IgG2a and IgG2b correlated with parasitological findings. This is the first report on cloning, expression, structural modeling and purification of rDIM-1bm and its ability to partially prevent establishment of B. malayi infection. DIM-1bm's almost complete lack of homology with the human counterpart makes it an attractive protein for exploring its vaccine potential. PMID:24513011

  13. Nuclear ribosome biogenesis mediated by the DIM1A rRNA dimethylase is required for organized root growth and epidermal patterning in Arabidopsis.

    PubMed

    Wieckowski, Yana; Schiefelbein, John

    2012-07-01

    Position-dependent patterning of hair and non-hair cells in the Arabidopsis thaliana root epidermis is a powerful system to study the molecular basis of cell fate specification. Here, we report an epidermal patterning mutant affecting the ADENOSINE DIMETHYL TRANSFERASE 1A (DIM1A) rRNA dimethylase gene, predicted to participate in rRNA posttranscriptional processing and base modification. Consistent with a role in ribosome biogenesis, DIM1A is preferentially expressed in regions of rapid growth, and its product is nuclear localized with nucleolus enrichment. Furthermore, DIM1A preferentially accumulates in the developing hair cells, and the dim1A point mutant alters the cell-specific expression of the transcriptional regulators GLABRA2, CAPRICE, and WEREWOLF. Together, these findings suggest that establishment of cell-specific gene expression during root epidermis development is dependent upon proper ribosome biogenesis, possibly due to the sensitivity of the cell fate decision to relatively small differences in gene regulatory activities. Consistent with its effect on the predicted S-adenosyl-l-Met binding site, dim1A plants lack the two 18S rRNA base modifications but exhibit normal pre-rRNA processing. In addition to root epidermal defects, the dim1A mutant exhibits abnormal root meristem division, leaf development, and trichome branching. Together, these findings provide new insights into the importance of rRNA base modifications and translation regulation for plant growth and development.

  14. Fluorescent reporters for Staphylococcus aureus.

    PubMed

    Malone, Cheryl L; Boles, Blaise R; Lauderdale, Katherine J; Thoendel, Matthew; Kavanaugh, Jeffrey S; Horswill, Alexander R

    2009-06-01

    With the emergence of Staphylococcus aureus as a prominent pathogen in community and healthcare settings, there is a growing need for effective reporter tools to facilitate physiology and pathogenesis studies. Fluorescent proteins are ideal as reporters for their convenience in monitoring gene expression, performing host interaction studies, and monitoring biofilm growth. We have developed a suite of fluorescent reporter plasmids for labeling S. aureus cells. These plasmids encode either green fluorescent protein (GFP) or higher wavelength reporter variants for yellow (YFP) and red (mCherry) labeling. The reporters were placed under control of characterized promoters to enable constitutive or inducible expression. Additionally, plasmids were assembled with fluorescent reporters under control of the agr quorum-sensing and sigma factor B promoters, and the fluorescent response with wildtype and relevant mutant strains was characterized. Interestingly, reporter expression displayed a strong dependence on ribosome binding site (RBS) sequence, with the superoxide dismutase RBS displaying the strongest expression kinetics of the sequences examined. To test the robustness of the reporter plasmids, cell imaging was performed with fluorescence microscopy and cell populations were separated using florescence-activated cell sorting (FACS), demonstrating the possibilities of simultaneous monitoring of multiple S. aureus properties. Finally, a constitutive YFP reporter displayed stable, robust labeling of biofilm growth in a flow-cell apparatus. This toolbox of fluorescent reporter plasmids will facilitate cell labeling for a variety of different experimental applications. PMID:19264102

  15. Smart Grid Enabled EVSE

    SciTech Connect

    None, None

    2014-10-15

    The combined team of GE Global Research, Federal Express, National Renewable Energy Laboratory, and Consolidated Edison has successfully achieved the established goals contained within the Department of Energy’s Smart Grid Capable Electric Vehicle Supply Equipment funding opportunity. The final program product, shown charging two vehicles in Figure 1, reduces by nearly 50% the total installed system cost of the electric vehicle supply equipment (EVSE) as well as enabling a host of new Smart Grid enabled features. These include bi-directional communications, load control, utility message exchange and transaction management information. Using the new charging system, Utilities or energy service providers will now be able to monitor transportation related electrical loads on their distribution networks, send load control commands or preferences to individual systems, and then see measured responses. Installation owners will be able to authorize usage of the stations, monitor operations, and optimally control their electricity consumption. These features and cost reductions have been developed through a total system design solution.

  16. Effects of artificial dawn on subjective ratings of sleep inertia and dim light melatonin onset.

    PubMed

    Giménez, Marina C; Hessels, Martijn; van de Werken, Maan; de Vries, Bonnie; Beersma, Domien G M; Gordijn, Marijke C M

    2010-07-01

    The timing of work and social requirements has a negative impact on performance and well-being of a significant proportion of the population in our modern society due to a phenomenon known as social jetlag. During workdays, in the early morning, late chronotypes, in particular, suffer from a combination of a nonoptimal circadian phase and sleep deprivation. Sleep inertia, a transient period of lowered arousal after awakening, therefore, becomes more severe. In the present home study, the authors tested whether the use of an alarm clock with artificial dawn could reduce complaints of sleep inertia in people having difficulties in waking up early. The authors also examined whether these improvements were accompanied by a shift in the melatonin rhythm. Two studies were performed: Study 1: three conditions (0, 50, and 250 lux) and Study 2: two conditions (0 lux and self-selected dawn-light intensity). Each condition lasted 2 weeks. In both studies, the use of the artificial dawn resulted in a significant reduction of sleep inertia complaints. However, no significant shift in the onset of melatonin was observed after 2 weeks of using the artificial dawn of 250 lux or 50 lux compared to the control condition. A multilevel analysis revealed that only the presence of the artificial dawn, rather than shift in the dim light melatonin onset or timing of sleep offset, is related to the observed reduction of sleep inertia complaints. Mechanisms other than shift of circadian rhythms are needed to explain the positive results on sleep inertia of waking up with a dawn signal. PMID:20653451

  17. Dim light at night disrupts the short-day response in Siberian hamsters.

    PubMed

    Ikeno, Tomoko; Weil, Zachary M; Nelson, Randy J

    2014-02-01

    Photoperiodic regulation of physiology, morphology, and behavior is crucial for many animals to survive seasonally variable conditions unfavorable for reproduction and survival. The photoperiodic response in mammals is mediated by nocturnal secretion of melatonin under the control of a circadian clock. However, artificial light at night caused by recent urbanization may disrupt the circadian clock, as well as the photoperiodic response by blunting melatonin secretion. Here we examined the effect of dim light at night (dLAN) (5lux of light during the dark phase) on locomotor activity rhythms and short-day regulation of reproduction, body mass, pelage properties, and immune responses of male Siberian hamsters. Short-day animals reduced gonadal and body mass, decreased spermatid nuclei and sperm numbers, molted to a whiter pelage, and increased pelage density compared to long-day animals. However, animals that experienced short days with dLAN did not show these short-day responses. Moreover, short-day specific immune responses were altered in dLAN conditions. The nocturnal activity pattern was blunted in dLAN hamsters, consistent with the observation that dLAN changed expression of the circadian clock gene, Period1. In addition, we demonstrated that expression levels of genes implicated in the photoperiodic response, Mel-1a melatonin receptor, Eyes absent 3, thyroid stimulating hormone receptor, gonadotropin-releasing hormone, and gonadotropin-inhibitory hormone, were higher in dLAN animals than those in short-day animals. These results suggest that dLAN disturbs the circadian clock function and affects the molecular mechanisms of the photoperiodic response.

  18. The color of night: surface color categorization by color defective observers under dim illuminations.

    PubMed

    Pokorny, Joel; Lutze, Margaret; Cao, Dingcai; Zele, Andrew J

    2008-01-01

    People with normal trichromatic color vision experience variegated hue percepts under dim illuminations where only rod photoreceptors mediate vision. Here, hue perceptions were determined for persons with congenital color vision deficiencies over a wide range of light levels, including very low light levels where rods alone mediate vision. Deuteranomalous trichromats, deuteranopes and protanopes served as observers. The appearances of 24 paper color samples from the OSA Uniform Color Scales were gauged under successively dimmer illuminations from 10 to 0.0003 Lux (1.0 to -3.5 log Lux). Triads of samples were chosen representing each of eight basic color categories; "red," "pink," "orange," "yellow," "green," "blue," "purple," and "gray." Samples within each triad varied in lightness. Observers sorted samples into groups that they could categorize with specific color names. Above -0.5 log Lux, the dichromatic and anomalous trichromatic observers sorted the samples into the original representative color groups, with some exceptions. At light levels where rods alone mediate vision, the color names assigned by the deuteranomalous trichromats were similar to the color names used by color normals; higher scotopic reflectance samples were classified as blue-green-grey and lower reflectance samples as red-orange. Color names reported by the dichromats at the dimmest light levels had extensive overlap in their sample scotopic lightness distributions. Dichromats did not assign scotopic color names based on the sample scotopic lightness, as did deuteranomalous trichromats and colour-normals. We reasoned that the reduction in color gamut that a dichromat experiences at photopic light levels leads to a limited association of rod color perception with objects differing in scotopic reflectance. PMID:18598421

  19. Exposure to dim artificial light at night increases REM sleep and awakenings in humans.

    PubMed

    Cho, Chul-Hyun; Lee, Heon-Jeong; Yoon, Ho-Kyoung; Kang, Seung-Gul; Bok, Ki-Nam; Jung, Ki-Young; Kim, Leen; Lee, Eun-Il

    2016-01-01

    Exposure to artificial light at night (ALAN) has become increasing common, especially in developed countries. We investigated the effect of dALAN exposure during sleep in healthy young male subjects. A total of 30 healthy young male volunteers from 21 to 29 years old were recruited for the study. They were randomly divided into two groups depending on light intensity (Group A: 5 lux and Group B: 10 lux). After a quality control process, 23 healthy subjects were included in the study (Group A: 11 subjects, Group B: 12 subjects). Subjects underwent an NPSG session with no light (Night 1) followed by an NPSG session randomly assigned to two different dim light conditions (5 or 10 lux, dom λ: 501.4 nm) for a whole night (Night 2). We found significant sleep structural differences between Nights 1 and 2, but no difference between Groups A and B. Exposure to dALAN during sleep was significantly associated with increased wake time after sleep onset (WASO; F = 7.273, p = 0.014), increased Stage N1 (F = 4.524, p = 0.045), decreased Stage N2 (F = 9.49, p = 0.006), increased Stage R (F = 6.698, p = 0.017) and non-significantly decreased REM density (F = 4.102, p = 0.056). We found that dALAN during sleep affects sleep structure. Exposure to dALAN during sleep increases the frequency of arousals, amount of shallow sleep and amount of REM sleep. This suggests adverse effects of dALAN during sleep on sleep quality and suggests the need to avoid exposure to dALAN during sleep.

  20. Dim light at night interacts with intermittent hypoxia to alter cognitive and affective responses

    PubMed Central

    Weil, Zachary M.; Magalang, Ulysses J.; Nelson, Randy J.

    2013-01-01

    Obstructive sleep apnea (OSA) and dim light at night (dLAN) have both been independently associated with alterations in mood and cognition. We aimed to determine whether dLAN would interact with intermittent hypoxia (IH), a condition characteristic of OSA, to alter the behavioral, cognitive, and affective responses. Adult male mice were housed in either standard lighting conditions (14:10-h light-dark cycle; 150 lux:0 lux) or dLAN (150 lux:5 lux). Mice were then exposed to IH (15 cycles/h, 8 h/day, FiO2 nadir of 5%) for 3 wk, then tested in assays of affective and cognitive responses; brains were collected for dendritic morphology and PCR analysis. Exposure to dLAN and IH increased anxiety-like behaviors, as assessed in the open field, elevated plus maze, and the light/dark box. dLAN and IH increased depressive-like behaviors in the forced swim test. IH impaired learning and memory performance in the passive avoidance task; however, no differences were observed in spatial working memory, as assessed by y-maze or object recognition. IH combined with dLAN decreased cell body area in the CA1 and CA3 regions of the hippocampus. Overall, IH decreased apical spine density in the CA3, whereas dLAN decreased spine density in the CA1 of the hippocampus. TNF-α gene expression was not altered by IH or lighting condition, whereas VEGF expression was increased by dLAN. The combination of IH and dLAN provokes negative effects on hippocampal dendritic morphology, affect, and cognition, suggesting that limiting nighttime exposure to light in combination with other established treatments may be of benefit to patients with OSA. PMID:23657638

  1. Dimming over the oceans: mixed layer ocean experiments from 1870 to 2000

    NASA Astrophysics Data System (ADS)

    Dallafior, Tanja; Folini, Doris; Knutti, Reto; Wild, Martin

    2015-04-01

    Sea surface temperature (SSTs) changes are known to affect precipitation patterns. However, it is still subject to debate, whether anthropogenic aerosols are capable of affecting SSTs, which could feed back on precipitation patterns. To influence SSTs, anthropogenic aerosols need to reduce incoming surface solar radiation (SSR) through direct or indirect effects for a sufficiently long time span over a sufficiently large area. To quantify the maximum potential SST response to anthropogenic aerosol dimming over the past decades, we performed equilibrium experiments with the general circulation model, ECHAM and explicit aerosol representation (ECHAM6-HAM2.2) and a mixed-layer ocean (MLO). Every ten years, we let the system equilibrate to the conditions (aerosol and greenhouse gas burdens, GHG) of that specific year. Each experiment is conducted over 50 years, of which the first 10 years are discarded. We generated three sets of decadal equilibria covering the entire 20th century and part of the 19th century (from 1870) : One, where both GHG and anthropogenic aerosols are set to the respective decade, one where GHG levels are held constant at 1850s levels, and one where anthropogenic aerosols are held constant at 1850s levels. Deep ocean heat fluxes are prescribed based on the surface energy flux climatology derived from an atmosphere-only integration with pre-industrial (year 1850) conditions for aerosols and GHG and climatological SSTs (average of Hadley Center SSTs, observation based, over the years 1871-1900). Results of these findings will be discussed, especially the SST and precipitation responses seen in the different equilibria. Moreover, results will be put in context with transient experiments with prescribed SSTs. The presented results are part of a project aiming at quantifying the effect of anthropogenic aerosols on SSTs. The results will serve as a basis for future experiments using a dynamic ocean model to quantify the transient response of the ocean

  2. Spectral Changes in Metal Halide and High-pressure Sodium Lamps Equipped with Electronic Dimming

    NASA Technical Reports Server (NTRS)

    Bubenheim, David L.; Sargis, Raman; Wilson, David

    1995-01-01

    Electronic dimming of high-intensity discharge lamps offers control of photosynthetic photon flux (PPF) but is often characterized as causing significant spectral changes. Growth chambers with 400-W metal halide (MH) and high-pressure sodium (HPS) lamps were equipped with a dimmer system using silicon-controlled rectifiers (SCR) as high-speed switches. Phase control operation turned the line power off for some period of the alternating current cycle. At full power, the electrical input to HPS and MH lamps was 480 W (root mean squared) and could be decreased to 267 W and 428 W, respectively, before the arc was extinguished. Concomitant with this decrease in input power, PPF decreased by 60% in HPS and 50% in MH. The HPS lamp has characteristic spectral peaks at 589 and 595 nm. As power to the HPS lamps was decreased, the 589-nm peak remained constant while the 595-nm peak decreased, equaling the 589-nm peak at 345-W input, and the 589-nm peak was almost absent at 270-W input. The MH lamp has a broader spectral output but also has a peak at 589 nm and another smaller peak at 545 nm. As input power to the MH lamps decreased, the peak at 589 diminished to equal the 545-nm peak. As input power approached 428 W, the 589-nm peak shifted to 570 nm. While the spectrum changed as input power was decreased in the MH and HPS lamps, the phytochrome equilibrium ratio (P(sub fr):P(sub tot)) remains unchanged for both lamp types.

  3. Enabling graphene nanoelectronics.

    SciTech Connect

    Pan, Wei; Ohta, Taisuke; Biedermann, Laura Butler; Gutierrez, Carlos; Nolen, C. M.; Howell, Stephen Wayne; Beechem Iii, Thomas Edwin; McCarty, Kevin F.; Ross, Anthony Joseph, III

    2011-09-01

    Recent work has shown that graphene, a 2D electronic material amenable to the planar semiconductor fabrication processing, possesses tunable electronic material properties potentially far superior to metals and other standard semiconductors. Despite its phenomenal electronic properties, focused research is still required to develop techniques for depositing and synthesizing graphene over large areas, thereby enabling the reproducible mass-fabrication of graphene-based devices. To address these issues, we combined an array of growth approaches and characterization resources to investigate several innovative and synergistic approaches for the synthesis of high quality graphene films on technologically relevant substrate (SiC and metals). Our work focused on developing the fundamental scientific understanding necessary to generate large-area graphene films that exhibit highly uniform electronic properties and record carrier mobility, as well as developing techniques to transfer graphene onto other substrates.

  4. Loss of Let-7 Up-Regulates EZH2 in Prostate Cancer Consistent with the Acquisition of Cancer Stem Cell Signatures That Are Attenuated by BR-DIM

    PubMed Central

    Kong, Dejuan; Heath, Elisabeth; Chen, Wei; Cher, Michael L.; Powell, Isaac; Heilbrun, Lance; Li, Yiwei; Ali, Shadan; Sethi, Seema; Hassan, Oudai; Hwang, Clara; Gupta, Nilesh; Chitale, Dhananjay; Sakr, Wael A.; Menon, Mani; Sarkar, Fazlul H.

    2012-01-01

    The emergence of castrate-resistant prostate cancer (CRPC) contributes to the high mortality of patients diagnosed with prostate cancer (PCa), which in part could be attributed to the existence and the emergence of cancer stem cells (CSCs). Recent studies have shown that deregulated expression of microRNAs (miRNAs) contributes to the initiation and progression of PCa. Among several known miRNAs, let-7 family appears to play a key role in the recurrence and progression of PCa by regulating CSCs; however, the mechanism by which let-7 family contributes to PCa aggressiveness is unclear. Enhancer of Zeste homolog 2 (EZH2), a putative target of let-7 family, was demonstrated to control stem cell function. In this study, we found loss of let-7 family with corresponding over-expression of EZH2 in human PCa tissue specimens, especially in higher Gleason grade tumors. Overexpression of let-7 by transfection of let-7 precursors decreased EZH2 expression and repressed clonogenic ability and sphere-forming capacity of PCa cells, which was consistent with inhibition of EZH2 3′UTR luciferase activity. We also found that the treatment of PCa cells with BR-DIM (formulated DIM: 3,3′-diindolylmethane by Bio Response, Boulder, CO, abbreviated as BR-DIM) up-regulated let-7 and down-regulated EZH2 expression, consistent with inhibition of self-renewal and clonogenic capacity. Moreover, BR-DIM intervention in our on-going phase II clinical trial in patients prior to radical prostatectomy showed upregulation of let-7 consistent with down-regulation of EZH2 expression in PCa tissue specimens after BR-DIM intervention. These results suggest that the loss of let-7 mediated increased expression of EZH2 contributes to PCa aggressiveness, which could be attenuated by BR-DIM treatment, and thus BR-DIM is likely to have clinical impact. PMID:22442719

  5. Enabling immersive simulation.

    SciTech Connect

    McCoy, Josh; Mateas, Michael; Hart, Derek H.; Whetzel, Jonathan; Basilico, Justin Derrick; Glickman, Matthew R.; Abbott, Robert G.

    2009-02-01

    The object of the 'Enabling Immersive Simulation for Complex Systems Analysis and Training' LDRD has been to research, design, and engineer a capability to develop simulations which (1) provide a rich, immersive interface for participation by real humans (exploiting existing high-performance game-engine technology wherever possible), and (2) can leverage Sandia's substantial investment in high-fidelity physical and cognitive models implemented in the Umbra simulation framework. We report here on these efforts. First, we describe the integration of Sandia's Umbra modular simulation framework with the open-source Delta3D game engine. Next, we report on Umbra's integration with Sandia's Cognitive Foundry, specifically to provide for learning behaviors for 'virtual teammates' directly from observed human behavior. Finally, we describe the integration of Delta3D with the ABL behavior engine, and report on research into establishing the theoretical framework that will be required to make use of tools like ABL to scale up to increasingly rich and realistic virtual characters.

  6. Displays enabling mobile multimedia

    NASA Astrophysics Data System (ADS)

    Kimmel, Jyrki

    2007-02-01

    With the rapid advances in telecommunications networks, mobile multimedia delivery to handsets is now a reality. While a truly immersive multimedia experience is still far ahead in the mobile world, significant advances have been made in the constituent audio-visual technologies to make this become possible. One of the critical components in multimedia delivery is the mobile handset display. While such alternatives as headset-style near-to-eye displays, autostereoscopic displays, mini-projectors, and roll-out flexible displays can deliver either a larger virtual screen size than the pocketable dimensions of the mobile device can offer, or an added degree of immersion by adding the illusion of the third dimension in the viewing experience, there are still challenges in the full deployment of such displays in real-life mobile communication terminals. Meanwhile, direct-view display technologies have developed steadily, and can provide a development platform for an even better viewing experience for multimedia in the near future. The paper presents an overview of the mobile display technology space with an emphasis on the advances and potential in developing direct-view displays further to meet the goal of enabling multimedia in the mobile domain.

  7. Wet, Dry, Dim, or Bright? The Future of Water Resources in North Texas

    NASA Astrophysics Data System (ADS)

    Brikowski, T. H.

    2009-12-01

    Future water resource availability in North Texas (Dallas-Ft. Worth Metroplex) is likely to be limited by the combined impact of decadal-scale and longer term climate changes. Two decadal precipitation anomalies are statistically distinguishable in the historical record (dry/wet, Table 1). These correspond temporally with the onset of global dimming/brightening events (hydrologic cycle retardation/acceleration) respectively (Table 1). Surface water hydrologic parameters are variably correlated with these events, depending on the degree of time-integration of each process. Precipitation correlates most strongly with the decadal anomalies. Runoff changes during these periods were magnified relative to precipitation changes, presumably an effect of soil moisture changes, and over the basin as a whole correlate best with the global events. Palmer Drought Severity Index (PDSI) attempts to capture such effects, and also correlates most strongly with the global events. The most important time-integrators of the system, reservoirs, show mixed correlation in terms of total storage with the decadal and longer term climate periods. Reservoir flood releases (excess storage) correlate with decadal precipitation anomalies, in part reflecting short-term consumption influences. Major reservoirs in the area post-date the dry period, precluding direct evaluation of sustainability from historical records. Historical correlations versus PDSI can be combined with climate-model based PDSI projections to evaluate future sustainability. Climate projections based on a mean of 19 IPCC intermediate scenario (SRESa1b) models indicate an approximately 10% reduction in mean annual precipitation, and warming of 2oC by 2050 in this region. Steady lowering of mean annual PDSI results, with a 50% probability that annual PDSI will average -0.5 by 2050. Average climate will move from humid (Aridity Index=35) to semi-humid (AI=27), and runoff can be expected to decline accordingly. Probability of a

  8. Fluorescence guidance during stereotactic biopsy

    NASA Astrophysics Data System (ADS)

    Stepp, Herbert; Beyer, Wolfgang; Brucker, David; Ehrhardt, Andre; Fischer, Stefan; Goebel, Werner; Goetz, Marcus; Guenther, Bettina; Hennig, Georg; Herms, Jochen; Irion, Klaus-Martin; Johansson, Ann; Kienast, Yvonne; Kniebuehler, Gesa; Li, Pan; Ruehm, Adrian; Sandner, Sabine

    2012-02-01

    Objective: When a stereotactic biopsy is taken to enable histopathological diagnosis of a suspected brain tumor, it is essential to i) do this safely, that is not injure a major blood vessel and ii) to obtain relevant vital material from the tumor. We are investigating the suitability of Indocyanine Green (ICG) fluorescence for blood vessel recognition and 5- Aminolevulinic acid (5-ALA) induced Protoporphyrin IX (PpIX) fluorescence for identification of proliferative brain tumor tissue. Methods: A fiber-optic endoscopic approach was studied to generate and detect both fluorescence signals. PpIX concentrations in brain tumors have been measured by chemical extraction. Preliminary equipment was studied in a mouse model. Results: PpIX-concentrations in glioblastoma tissue showed high inner- and inter-patient variability, but each patient out of 15 with interpretable data showed at least one sample with a PpIX-concentration exceeding 2.4 μmol/l, which is easily detectable by state-of-the-art fiberoptic fluorescence spectroscopy and imaging. The imaging fluoroscope with 30,000 pixels resolution could be introduced through a position controlled stereotactic needle. ICG-fluorescence from vessels with diameters >= 0.1 mm can be detected with a contrast of 2-2.5 against surrounding tissue. Conclusion: Fluorescence detection during stereotactic biopsy might increase safety and precision of the procedure significantly.

  9. HINODE/XRT AND STEREO OBSERVATIONS OF A DIFFUSE CORONAL 'WAVE'-CORONAL MASS EJECTION-DIMMING EVENT

    SciTech Connect

    Attrill, Gemma D. R.; Engell, Alexander J.; Wills-Davey, Meredith J.; Grigis, Paolo; Testa, Paola

    2009-10-20

    We report on observations of the first diffuse coronal wave detected by Hinode/XRT. The event occurred near the west solar limb on 2007 May 23, originating from active region (AR) 10956 and was associated with a coronal mass ejection (CME) and coronal dimmings. The bright emission forming the coronal wave expanded predominantly to the east and south of the AR. We use X-Ray Telescope (XRT) and STEREO Behind (B) data combined with a potential magnetic field extrapolation to derive an understanding of the global magnetic field connectivity. We attribute the brightening to the east of the AR to compression and channeling of the plasma along large-scale loops. The brightening to the south of the AR expands across the quiet Sun, making the southern component a likely candidate for identification as a diffuse coronal wave. We analyze the bright front in STEREO/EUVI (B) 171, 195, and 284 A images, as well as in XRT data, finding the strongest components to be largely cospatial in all bandpasses. We also exploit the near-limb location of this event by combining STEREO/COR1 and Extreme Ultra-Violet Imaging Telescope (EUVI) data. Using all the data, we derive a full picture of the low-coronal development of the eruption. The COR1 data show that the southernmost outer edge of the CME is progressively displaced southward during the expansion. EUVI data below the COR1 occulting disk show that the CME is significantly distorted in the low corona as a result of the associated filament eruption. The core coronal dimmings map to the core of the CME; the secondary coronal dimmings map to the CME cavity; and the diffuse coronal wave maps to the outermost edge of the expanding CME shell. The analysis of this near-limb event has important implications for understanding earlier eruptions originating from the same AR on 2007 May 16, 19, and 20.

  10. Nano-Enabled SERS Reporting Photosensitizers

    PubMed Central

    Farhadi, Arash; Roxin, Áron; Wilson, Brian C.; Zheng, Gang

    2015-01-01

    To impart effective cellular damage via photodynamic therapy (PDT), it is vital to deliver the appropriate light dose and photosensitizer concentration, and to monitor the PDT dose delivered at the site of interest. In vivo monitoring of photosensitizers has in large part relied on their fluorescence emission. Palladium-containing photosensitizers have shown promising clinical results by demonstrating near full conversion of light to PDT activity at the cost of having undetectable fluorescence. We demonstrate that, through the coupling of plasmonic nanoparticles with palladium-photosensitizers, surface-enhanced Raman scattering (SERS) provides both reporting and monitoring capability to otherwise quiescent molecules. Nano-enabled SERS reporting of photosensitizers allows for the decoupling of the therapeutic and imaging mechanisms so that both phenomena can be optimized independently. Most importantly, the design enables the use of the same laser wavelength to stimulate both the PDT and imaging features, opening the potential for real-time dosimetry of photosensitizer concentration and PDT dose delivery by SERS monitoring. PMID:25767614

  11. Research on infrared dim-point target detection and tracking under sea-sky-line complex background

    NASA Astrophysics Data System (ADS)

    Dong, Yu-xing; Li, Yan; Zhang, Hai-bo

    2011-08-01

    Target detection and tracking technology in infrared image is an important part of modern military defense system. Infrared dim-point targets detection and recognition under complex background is a difficulty and important strategic value and challenging research topic. The main objects that carrier-borne infrared vigilance system detected are sea-skimming aircrafts and missiles. Due to the characteristics of wide field of view of vigilance system, the target is usually under the sea clutter. Detection and recognition of the target will be taken great difficulties .There are some traditional point target detection algorithms, such as adaptive background prediction detecting method. When background has dispersion-decreasing structure, the traditional target detection algorithms would be more useful. But when the background has large gray gradient, such as sea-sky-line, sea waves etc .The bigger false-alarm rate will be taken in these local area .It could not obtain satisfactory results. Because dim-point target itself does not have obvious geometry or texture feature ,in our opinion , from the perspective of mathematics, the detection of dim-point targets in image is about singular function analysis .And from the perspective image processing analysis , the judgment of isolated singularity in the image is key problem. The foregoing points for dim-point targets detection, its essence is a separation of target and background of different singularity characteristics .The image from infrared sensor usually accompanied by different kinds of noise. These external noises could be caused by the complicated background or from the sensor itself. The noise might affect target detection and tracking. Therefore, the purpose of the image preprocessing is to reduce the effects from noise, also to raise the SNR of image, and to increase the contrast of target and background. According to the low sea-skimming infrared flying small target characteristics , the median filter is used to

  12. Beryllium increases the CD14(dim)CD16+ subset in the lung of chronic beryllium disease.

    PubMed

    Li, Li; Hamzeh, Nabeel; Gillespie, May; Elliott, Jill; Wang, Jieru; Gottschall, Eva Brigitte; Mroz, Peggy M; Maier, Lisa A

    2015-01-01

    CD14dimCD16+ and CD14brightCD16+ cells, which compose a minor population of monocytes in human peripheral blood mononuclear cells (PBMC), have been implicated in several inflammatory diseases. The aim of this study was to investigate whether this phenotype was present as a subset of lung infiltrative alveolar macrophages (AMs) in the granulomatous lung disease, chronic beryllium disease (CBD). The monocytes subsets was determined from PBMC cells and bronchoalveolar lavage (BAL) cells from CBD, beryllium sensitized Non-smoker (BeS-NS) and healthy subjects (HS) using flow cytometry. The impact of smoking on the AMs cell phenotype was determined by using BAL cells from BeS smokers (BeS-S). In comparison with the other monocyte subpopulations, CD14dimCD16+ cells were at decreased frequency in PBMCs of both BeS-NS and CBD and showed higher HLA-DR expression, compared to HS. The AMs from CBD and BeS-NS demonstrated a CD14dimCD16+phenotype, while CD14brightCD16+ cells were found at increased frequency in AMs of BeS, compared to HS. Fresh AMs from BeS-NS and CBD demonstrated significantly greater CD16, CD40, CD86 and HLA-DR than HS and BeS-S. The expression of CD16 on AMs from both CBD and BeS-NS was downregulated significantly after 10μM BeSO4 stimulation. The phagocytic activity of AMs decreased after 10μM BeSO4 treatment in both BeS-NS and CBD, although was altered or reduced in HS and BeS-S. These results suggest that Be increases the CD14dimCD16+ subsets in the lung of CBD subjects. We speculate that Be-stimulates the compartmentalization of a more mature CD16+ macrophage phenotype and that in turn these macrophages are a source of Th1 cytokines and chemokines that perpetuate the Be immune response in CBD. The protective effect of cigarette smoking in BeS-S may be due to the low expression of co-stimulatory markers on AMs from smokers as well as the decreased phagocytic function.

  13. A small dim infrared maritime target detection algorithm based on local peak detection and pipeline-filtering

    NASA Astrophysics Data System (ADS)

    Wang, Bin; Dong, Lili; Zhao, Ming; Xu, Wenhai

    2015-12-01

    In order to realize accurate detection for small dim infrared maritime target, this paper proposes a target detection algorithm based on local peak detection and pipeline-filtering. This method firstly extracts some suspected targets through local peak detection and removes most of non-target peaks with self-adaptive threshold process. And then pipeline-filtering is used to eliminate residual interferences so that only real target can be retained. The experiment results prove that this method has high performance on target detection, and its missing alarm rate and false alarm rate can basically meet practical requirements.

  14. Enabling responsible public genomics.

    PubMed

    Conley, John M; Doerr, Adam K; Vorhaus, Daniel B

    2010-01-01

    As scientific understandings of genetics advance, researchers require increasingly rich datasets that combine genomic data from large numbers of individuals with medical and other personal information. Linking individuals' genetic data and personal information precludes anonymity and produces medically significant information--a result not contemplated by the established legal and ethical conventions governing human genomic research. To pursue the next generation of human genomic research and commerce in a responsible fashion, scientists, lawyers, and regulators must address substantial new issues, including researchers' duties with respect to clinically significant data, the challenges to privacy presented by genomic data, the boundary between genomic research and commerce, and the practice of medicine. This Article presents a new model for understanding and addressing these new challenges--a "public genomics" premised on the idea that ethically, legally, and socially responsible genomics research requires openness, not privacy, as its organizing principle. Responsible public genomics combines the data contributed by informed and fully consenting information altruists and the research potential of rich datasets in a genomic commons that is freely and globally available. This Article examines the risks and benefits of this public genomics model in the context of an ambitious genetic research project currently under way--the Personal Genome Project. This Article also (i) demonstrates that large-scale genomic projects are desirable, (ii) evaluates the risks and challenges presented by public genomics research, and (iii) determines that the current legal and regulatory regimes restrict beneficial and responsible scientific inquiry while failing to adequately protect participants. The Article concludes by proposing a modified normative and legal framework that embraces and enables a future of responsible public genomics.

  15. FOILFEST :community enabled security.

    SciTech Connect

    Moore, Judy Hennessey; Johnson, Curtis Martin; Whitley, John B.; Drayer, Darryl Donald; Cummings, John C., Jr.

    2005-09-01

    The Advanced Concepts Group of Sandia National Laboratories hosted a workshop, ''FOILFest: Community Enabled Security'', on July 18-21, 2005, in Albuquerque, NM. This was a far-reaching look into the future of physical protection consisting of a series of structured brainstorming sessions focused on preventing and foiling attacks on public places and soft targets such as airports, shopping malls, hotels, and public events. These facilities are difficult to protect using traditional security devices since they could easily be pushed out of business through the addition of arduous and expensive security measures. The idea behind this Fest was to explore how the public, which is vital to the function of these institutions, can be leveraged as part of a physical protection system. The workshop considered procedures, space design, and approaches for building community through technology. The workshop explored ways to make the ''good guys'' in public places feel safe and be vigilant while making potential perpetrators of harm feel exposed and convinced that they will not succeed. Participants in the Fest included operators of public places, social scientists, technology experts, representatives of government agencies including DHS and the intelligence community, writers and media experts. Many innovative ideas were explored during the fest with most of the time spent on airports, including consideration of the local airport, the Albuquerque Sunport. Some provocative ideas included: (1) sniffers installed in passage areas like revolving door, escalators, (2) a ''jumbotron'' showing current camera shots in the public space, (3) transparent portal screeners allowing viewing of the screening, (4) a layered open/funnel/open/funnel design where open spaces are used to encourage a sense of ''communitas'' and take advantage of citizen ''sensing'' and funnels are technological tunnels of sensors (the tunnels of truth), (5) curved benches with blast proof walls or backs, (6

  16. Quantitative assessment of fluorescent proteins.

    PubMed

    Cranfill, Paula J; Sell, Brittney R; Baird, Michelle A; Allen, John R; Lavagnino, Zeno; de Gruiter, H Martijn; Kremers, Gert-Jan; Davidson, Michael W; Ustione, Alessandro; Piston, David W

    2016-07-01

    The advent of fluorescent proteins (FPs) for genetic labeling of molecules and cells has revolutionized fluorescence microscopy. Genetic manipulations have created a vast array of bright and stable FPs spanning blue to red spectral regions. Common to autofluorescent FPs is their tight β-barrel structure, which provides the rigidity and chemical environment needed for effectual fluorescence. Despite the common structure, each FP has unique properties. Thus, there is no single 'best' FP for every circumstance, and each FP has advantages and disadvantages. To guide decisions about which FP is right for a given application, we have quantitatively characterized the brightness, photostability, pH stability and monomeric properties of more than 40 FPs to enable straightforward and direct comparison between them. We focus on popular and/or top-performing FPs in each spectral region. PMID:27240257

  17. Bright versus dim ambient light affects subjective well-being but not serotonin-related biological factors.

    PubMed

    Stemer, Bettina; Melmer, Andreas; Fuchs, Dietmar; Ebenbichler, Christoph; Kemmler, Georg; Deisenhammer, Eberhard A

    2015-10-30

    Light falling on the retina is converted into an electrical signal which stimulates serotonin synthesis. Previous studies described an increase of plasma and CNS serotonin levels after bright light exposure. Ghrelin and leptin are peptide hormones which are involved in the regulation of hunger/satiety and are related to serotonin. Neopterin and kynurenine are immunological markers which are also linked to serotonin biosynthesis. In this study, 29 healthy male volunteers were exposed to bright (5000lx) and dim (50lx) light conditions for 120min in a cross-over manner. Subjective well-being and hunger as well as various serotonin associated plasma factors were assessed before and after light exposure. Subjective well-being showed a small increase under bright light and a small decrease under dim light, resulting in a significant interaction between light condition and time. Ghrelin concentrations increased significantly under both light conditions, but there was no interaction between light and time. Correspondingly, leptin decreased significantly under both light conditions. Hunger increased significantly with no light-time interaction. We also found a significant decrease of neopterin, tryptophan and tyrosine levels, but no interaction between light and time. In conclusion, ambient light was affecting subjective well-being rather than serotonin associated biological factors.

  18. Long-term changes of aerosol optical and radiative properties and their role in global dimming and brightening

    NASA Astrophysics Data System (ADS)

    Hatzianastassiou, N.; Papadimas, C. D.; Matsoukas, C.; Pavlakis, K.; Fotiadi, A.; Wild, M.; Vardavas, I.

    2009-04-01

    Global dimming and brightening (GDB) have profound effects on the Earth's environment. For example, GDB counteracts or supplements greenhouse warming. Atmospheric aerosols, through their interaction with solar radiation (direct, indirect and semi-direct effects) can affect GDB. Changes in aerosol burden or other physical and optical properties can modify tendencies of GDB. For example, satellite observations of aerosol amounts, available since the early 1980s, but only over the oceans, indicate a downward trend since about 1990, consistent with the observed brightening during this period. There is a need, however, to investigate similar trends, but also over land, and to relate them with contemporary GDB. The seasonal and inter-annual variability of the natural, but also anthropogenic aerosol direct radiative effect on solar radiation at the Earth's surface (DREsurf) and the contribution of aerosols to global dimming and brightening (GDB) is estimated over the period 1984-2001. This is achieved by using a spectral radiative transfer model together with Total Ozone Mapping Spectrometer (TOMS) aerosol optical thickness (AOT) and other satellite (International Satellite Cloud Climatology Project, ISCCP-D2), NCEP/NCAR reanalysis and Global Aerosol Data Set (GADS) data for surface and atmospheric parameters. The major findings are mostly related to natural and less to anthropogenic aerosols because of limitations of the TOMS observational technique. The model results indicate that aerosols exert a strong surface cooling over the globe by reducing locally the incoming surface solar radiation by up to 70 W m-2. This direct radiative effect averaged over the globe for the period 1984-2001, is equivalent to 5 W m-2, associated with 6.5 and 3.5 W m-2, for the Northern and Southern Hemispheres, respectively. However, this aerosol DREsurf effect shows an important inter-annual variability as large as 200%. A strong solar brightening, or decreased aerosol DREsurf, by as much as

  19. Acute dim light at night increases body mass, alters metabolism, and shifts core body temperature circadian rhythms.

    PubMed

    Borniger, Jeremy C; Maurya, Santosh K; Periasamy, Muthu; Nelson, Randy J

    2014-10-01

    The circadian system is primarily entrained by the ambient light environment and is fundamentally linked to metabolism. Mounting evidence suggests a causal relationship among aberrant light exposure, shift work, and metabolic disease. Previous research has demonstrated deleterious metabolic phenotypes elicited by chronic (>4 weeks) exposure to dim light at night (DLAN) (∼ 5 lux). However, the metabolic effects of short-term (<2 weeks) exposure to DLAN are unspecified. We hypothesized that metabolic alterations would arise in response to just 2 weeks of DLAN. Specifically, we predicted that mice exposed to dim light would gain more body mass, alter whole body metabolism, and display altered body temperature (Tb) and activity rhythms compared to mice maintained in dark nights. Our data largely support these predictions; DLAN mice gained significantly more mass, reduced whole body energy expenditure, increased carbohydrate over fat oxidation, and altered temperature circadian rhythms. Importantly, these alterations occurred despite similar activity locomotor levels (and rhythms) and total food intake between groups. Peripheral clocks are potently entrained by body temperature rhythms, and the deregulation of body temperature we observed may contribute to metabolic problems due to "internal desynchrony" between the central circadian oscillator and temperature sensitive peripheral clocks. We conclude that even relatively short-term exposure to low levels of nighttime light can influence metabolism to increase mass gain.

  20. A Global Model Simulation of Aerosol Effects of Surface Radiation Budget- Toward Understanding of the "Dimming to Brightening" Transition

    NASA Technical Reports Server (NTRS)

    Chin, Mian; Diehl, Thomas; Bian, Huisheng; Yu, Hongbin

    2008-01-01

    We present a global model study on the role aerosols play in the change of solar radiation at Earth's surface that transitioned from a decreasing (dimming) trend to an increasing (brightening) trend. Our primary objective is to understand the relationship between the long-term trends of aerosol emission, atmospheric burden, and surface solar radiation. More specifically, we use the recently compiled comprehensive global emission datasets of aerosols and precursors from fuel combustion, biomass burning, volcanic eruptions and other sources from 1980 to 2006 to simulate long-term variations of aerosol distributions and optical properties, and then calculate the multi-decadal changes of short-wave radiative fluxes at the surface and at the top of the atmosphere by coupling the GOCART model simulated aerosols with the Goddard radiative transfer model. The model results are compared with long-term observational records from ground-based networks and satellite data. We will address the following critical questions: To what extent can the observed surface solar radiation trends, known as the transition from dimming to brightening, be explained by the changes of anthropogenic and natural aerosol loading on global and regional scales? What are the relative contributions of local emission and long-range transport to the surface radiation budget and how do these contributions change with time?

  1. CALiPER Report 20.2: Dimming, Flicker, and Power Quality Characteristics of LED PAR38 Lamps

    SciTech Connect

    None, None

    2014-03-31

    This report focuses on the flicker and power quality performance of the Series 20 lamps at full output and various dimmed levels. All of the Series 20 PAR38 lamps that manufacturers claimed to be dimmable (including all halogen lamps) were evaluated individually (one lamp at a time) both on a switch and under the control of a phase-cut dimmer designed for use with "all classes of bulbs." Measurements of luminous flux, flicker, and power quality were taken at 10 target dimmed settings and compared with operation on a switch. Because only a single unit of each product was evaluated on a single dimmer that may or may not have been recommended by its manufacturer, this report focuses on the performance of the products relative to each other, rather than the best-case performance of each lamp or variation in performance delivered from each lamp. Despite these limitations, the results suggest that LED performance is improving, and performance trends are beginning to emerge, perhaps due in part to the identification of preferred LED driver strategies for lamp products.

  2. Rectilinear-motion space inversion-based detection approach for infrared dim air targets with variable velocities

    NASA Astrophysics Data System (ADS)

    Ma, Tianlei; Shi, Zelin; Yin, Jian; Liu, Yunpeng; Xu, Baoshu; Zhang, Chengshuo

    2016-03-01

    Dim targets are extremely difficult to detect using methods based on single-frame detection. Radiation accumulation is one of the effective methods to improve signal-to-noise ratio (SNR). A detection approach based on radiation accumulation is proposed. First, a location space and a motion space are established. Radiation accumulation operation, controlled by vectors from the motion space, is applied to the original image space. Then, a new image space is acquired where some images have an improved SNR. Second, quasitargets in the new image space are obtained by constant false-alarm ratio judging, and location vectors and motion vectors of quasitargets are also acquired simultaneously. Third, the location vectors and motion vectors are mapped into the two spaces, respectively. Volume density function is defined in the motion space. Location extremum of the location space and volume density extremum of motion space will confirm the true target. Finally, actual location of the true target in the original image space is obtained by space inversion. The approach is also applicable to detect multiple dim targets. Experimental results show the effectiveness of the proposed approach and demonstrate the approach is superior to compared approaches on detection probability and false alarm probability.

  3. Terminal Differentiation of CD56(dim)CD16(+) Natural Killer Cells Is Associated with Increase in Natural Killer Cell Frequencies After Antiretroviral Treatment in HIV-1 Infection.

    PubMed

    Ahmad, Fareed; Tufa, Dejene Milkessa; Mishra, Neha; Jacobs, Roland; Schmidt, Reinhold E

    2015-12-01

    HIV-1 infection results in immunological abnormalities of natural killer (NK) cells such as disturbed distribution of NK cell subsets and downmodulation of activating and upregulation of inhibitory receptors thereby diminishing NK cell killing capacity and cytokine secretion. Antiretroviral treatment (ART) is known to restore phenotype and functions of NK cells. However, the effects of ART on NK cell terminal differentiation, activation, and disturbed distribution have not been studied yet longitudinally. Here, we analyzed the effects of ART on these parameters of peripheral blood NK cells in a longitudinal as well as in a cross-sectional study. We observed that expanded CD56(-)CD16(+) NK cell frequency is inversely correlated with the frequency of CD56(dim)CD16(+) NK cells in treatment-naive HIV-1 patients. Loss of CD56(dim)CD16(+) and expansion of CD56(-)CD16(+) NK cells again restore to the levels of healthy controls after ART. Enhanced immune activation of different NK cell subsets is partially restored after ART. Terminal differentiation of CD56(dim)CD16(+) NK cells is enhanced after ART as measured by CD57 expression. Frequencies of CD57(+)CD56(dim)CD16(+) NK cells are directly correlated with the frequencies of total NK cells suggesting that an increase in the frequencies of CD57(+)CD56(dim)CD16(+) NK cells is reflected by increased frequencies of total NK cells after ART. Taken together these data demonstrate that ART has an effect on the immune restoration of NK cells and is enhanced in the terminal differentiation of CD56(dim)CD16(+) NK cells, which is associated with increased frequencies of total NK cells after ART.

  4. Pharmacodynamics of dietary phytochemical indoles I3C and DIM: Induction of Nrf2-mediated phase II drug metabolizing and antioxidant genes and synergism with isothiocyanates.

    PubMed

    Saw, Constance Lay-Lay; Cintrón, Melvilí; Wu, Tien-Yuan; Guo, Yue; Huang, Ying; Jeong, Woo-Sik; Kong, Ah-Ng Tony

    2011-07-01

    The antioxidant response element (ARE) is a critical regulatory element for the expression of many phase II drug metabolizing enzymes (DME), phase III transporters and antioxidant enzymes, mediated by the transcription factor Nrf2. The aim of this study was to examine the potential activation and synergism of Nrf2-ARE-mediated transcriptional activity between four common phytochemicals present in cruciferous vegetables; the indoles: indole-3-carbinol (I3C), 3,3'-diindolylmethane (DIM); and the isothiocyanates (ITCs): phenethyl isothiocyanate (PEITC) and sulforaphane (SFN). The cytotoxicity of the compounds was determined in a human liver hepatoma cell line (HepG2-C8). The combination index was calculated to assess the synergistic effects on the induction of ARE-mediated gene expressions. Quantitative real-time polymerase chain reaction (qPCR) was employed to measure the mRNA expressions of Nrf2 and Nrf2-mediated genes. I3C and DIM showed less cytotoxicity than SFN and PEITC. Compared with I3C, DIM was found to be a stronger inducer of ARE. Synergism was observed after combined treatments of 6.25 µm I3C + 1 µm SFN, 6.25 µm I3C + 1 µm PEITC and 6.25 µm DIM + 1 µm PEITC, while an additive effect was observed for 6.25 µm DIM + 1 µm SFN. Induction of endogenous Nrf2, phase II genes (GSTm2, UGT1A1 and NQO1) and antioxidant genes (HO-1 and SOD1) was also observed. In summary, the indole I3C or DIM alone could induce or syngergistically induce in combination with the ITCs SFN or PEITC, Nrf2-ARE-mediated gene expression, which could potentially enhance cancer chemopreventive activity. PMID:21656528

  5. Fluorescence of dental porcelain.

    PubMed

    Monsénégo, G; Burdairon, G; Clerjaud, B

    1993-01-01

    This study of the fluorescence of natural enamel and of dental ceramics shows the fluorescence of ceramics not containing rare earths decreases when the color saturation increases; the fluorescence of samples of the same shade guide are not homogenous; some guides show a strong green fluorescence; and two shade guides of the same origin can present completely different fluorescence. The cementing medium can affect the fluorescence of a ceramic prosthesis. PMID:8455155

  6. Night vision by cuttlefish enables changeable camouflage.

    PubMed

    Allen, Justine J; Mäthger, Lydia M; Buresch, Kendra C; Fetchko, Thomas; Gardner, Meg; Hanlon, Roger T

    2010-12-01

    Because visual predation occurs day and night, many predators must have good night vision. Prey therefore exhibit antipredator behaviours in very dim light. In the field, the giant Australian cuttlefish (Sepia apama) assumes camouflaged body patterns at night, each tailored to its immediate environment. However, the question of whether cuttlefish have the perceptual capability to change their camouflage at night (as they do in day) has not been addressed. In this study, we: (1) monitored the camouflage patterns of Sepia officinalis during the transition from daytime to night-time using a natural daylight cycle and (2) tested whether cuttlefish on a particular artificial substrate change their camouflage body patterns when the substrate is changed under dim light (down to starlight, 0.003 lux) in a controlled light field in a dark room setting. We found that cuttlefish camouflage patterns are indeed adaptable at night: animals responded to a change in their visual environment with the appropriate body pattern change. Whether to deceive their prey or predators, cuttlefish use their excellent night vision to perform adaptive camouflage in dim light. PMID:21075936

  7. Fluorescence microscopy: A tool to study autophagy

    NASA Astrophysics Data System (ADS)

    Rai, Shashank; Manjithaya, Ravi

    2015-08-01

    Autophagy is a cellular recycling process through which a cell degrades old and damaged cellular components such as organelles and proteins and the degradation products are reused to provide energy and building blocks. Dysfunctional autophagy is reported in several pathological situations. Hence, autophagy plays an important role in both cellular homeostasis and diseased conditions. Autophagy can be studied through various techniques including fluorescence based microscopy. With the advancements of newer technologies in fluorescence microscopy, several novel processes of autophagy have been discovered which makes it an essential tool for autophagy research. Moreover, ability to tag fluorescent proteins with sub cellular targets has enabled us to evaluate autophagy processes in real time under fluorescent microscope. In this article, we demonstrate different aspects of autophagy in two different model organisms i.e. yeast and mammalian cells, with the help of fluorescence microscopy.

  8. Radiative Transport Based Frequency Domain Fluorescence Tomography

    PubMed Central

    Joshi, Amit; Rasmussen, John C.; Sevick-Muraca, Eva M.; Wareing, Todd A.; McGhee, John

    2011-01-01

    We report the development of radiative transport model based fluorescence optical tomography from frequency domain boundary measurements. The coupled radiative transport model for describing NIR fluorescence propagation in tissue is solved by a novel software based on the established Attila™ particle transport simulation platform. The proposed scheme enables the prediction of fluorescence measurements with non-contact sources and detectors at minimal computational cost. An adjoint transport solution based fluorescence tomography algorithm is implemented on dual grids to efficiently assemble the measurement sensitivity Jacobian matrix. Finally, we demonstrate fluorescence tomography on a realistic computational mouse model to locate nM to μM fluorophore concentration distributions in simulated mouse organs. PMID:18364555

  9. Hadamard-transform fluorescence-lifetime imaging.

    PubMed

    Mizuno, Takahiko; Iwata, Tetsuo

    2016-04-18

    We discuss a Hadamard-transform-based fluorescence-lifetime-imaging (HT-FLI) technique for fluorescence-lifetime-imaging microscopy (FLIM). The HT-FLI uses a Fourier-transform phase-modulation fluorometer (FT-PMF) for fluorescence-lifetime measurements, where the modulation frequency of the excitation light is swept linearly in frequency from zero to a specific maximum during a fixed duration of time. Thereafter, fluorescence lifetimes are derived through Fourier transforms for the fluorescence and reference waveforms. The FT-PMF enables the analysis of multi-component samples simultaneously. HT imaging uses electronic exchange of HT illumination mask patterns, and a high-speed, high-sensitivity photomultiplier, to eliminate frame-rate issues that accompany two-dimensional image detectors. PMID:27137259

  10. Models of fluorescence and photosynthesis for interpreting measurements of solar-induced chlorophyll fluorescence

    PubMed Central

    van der Tol, C; Berry, J A; Campbell, P K E; Rascher, U

    2014-01-01

    We have extended a conventional photosynthesis model to simulate field and laboratory measurements of chlorophyll fluorescence at the leaf scale. The fluorescence paramaterization is based on a close nonlinear relationship between the relative light saturation of photosynthesis and nonradiative energy dissipation in plants of different species. This relationship diverged only among examined data sets under stressed (strongly light saturated) conditions, possibly caused by differences in xanthophyll pigment concentrations. The relationship was quantified after analyzing data sets of pulse amplitude modulated measurements of chlorophyll fluorescence and gas exchange of leaves of different species exposed to different levels of light, CO2, temperature, nitrogen fertilization treatments, and drought. We used this relationship in a photosynthesis model. The coupled model enabled us to quantify the relationships between steady state chlorophyll fluorescence yield, electron transport rate, and photosynthesis in leaves under different environmental conditions. Key Points Light saturation of photosynthesis determines quenching of leaf fluorescence We incorporated steady state leaf fluorescence in a photosynthesis model PMID:27398266

  11. A phase I dose-escalation study of oral BR-DIM (BioResponse 3,3′- Diindolylmethane) in castrate-resistant, non-metastatic prostate cancer

    PubMed Central

    Heath, Elisabeth I; Heilbrun, Lance K; Li, Jing; Vaishampayan, Ulka; Harper, Felicity; Pemberton, Pam; Sarkar, Fazlul H

    2010-01-01

    3, 3′-diindolylmethane (DIM) modulates estrogen metabolism and acts as an anti-androgen which down-regulates the androgen receptor and prostate specific antigen (PSA). We conducted a dose-escalation, phase I study of BioResponse (BR)-DIM with objectives to determine the maximum tolerated dose (MTD), toxicity profile, and phar-macokinetics (PK) of BR-DIM, and to assess its effects on serum PSA and quality of life (QoL). Patients and Methods: Cohorts of 3-6 patients received escalating doses of twice daily oral BR-DIM providing DIM at 75 mg, then 150 mg, 225 mg, and 300 mg. Toxicity was evaluated monthly. Serum PSA and QoL were measured at baseline, monthly during treatment, and at end of study. Results: 12 patients with castrate-resistant, non-metastatic, PSA relapse prostate cancer were treated over 4 dose cohorts; 2 patients (at 150 mg and 225 mg, respectively) underwent intra-patient dose escalation, by one dose level. After oral administration of the first dose of BR-DIM, the plasma exposure to DIM appeared dose proportional at doses ranging from 75 to 300 mg, with the mean Cmax and mean AUClast increasing from 41.6 to 236.4 ng/ml and from 192.0 to 899.0 ng/ml*h, respectively. Continued relatively stable systemic exposure to DIM was achieved following twice daily oral administration of BR-DIM. Minimal toxicity was observed. Two of the four patients treated at 300 mg had grade 3 asymptomatic hyponatremia (AH) discovered on routine blood work. The other 2 patients at this dose had no AH. Therefore, the maximum tolerated dose (MTD) was deemed to be 300 mgand the recommended phase II dose (RP2D) of BR-DIM was 225 mg twice daily. One patient without AH at 225 mg experienced a 50% PSA decline. One patient with BR-DIM dose of 225 mg had PSA stabilization. The other 10 patients had an initial deceleration of their PSA rise (decrease in slope), but eventually progressed based on continual PSA rise or evidence of metastatic disease. Ten patients completed monthly Qo

  12. Observed dimming effect during a forest fire in the southeastern United States and the role of aerosols

    NASA Astrophysics Data System (ADS)

    Prabha, Thara V.; Hoogenboom, Gerrit

    2009-06-01

    A surface dimming effect during a forest fire was observed in the incoming solar radiation measurements of the Georgia Automated Environmental Monitoring Network (AEMN). A combination of in situ AEMN and Moderate Resolution Imaging Spectroradiometer (MODIS) datasets were used to demonstrate the implications on the forecasts when aerosol radiative effects are not included in the Weather Research and Forecasting (WRF) model. The clear sky incoming radiative flux predicted by the model at the surface was overestimated when aerosol optical depths (AODs) exceeded 0.2, which in turn caused a positive temperature bias and a negative mixing ratio bias at the surface. These biases resulted from differences in the energy partitioning at the surface, where the main contribution was from enhanced sensible heat flux. The model atmosphere was also cooler and drier than the MODIS profiles, indicative of the aerosol induced warming below 6 km.

  13. Effects of extracellular calcium and of light adaptation on the response to dim light in honey bee drone photoreceptors.

    PubMed

    Raggenbass, M

    1983-11-01

    Light responses in honey bee drone photoreceptors were recorded with intracellular micro-electrodes in superfused slices of retina. The effects of changes in extracellular calcium on the size and the shape of the response to dim light were studied and compared with the effects of light adaptation. Dim light stimuli were used so that the amplitude of the response was linearly related to the number of the photons absorbed, the effects of voltage-dependent mechanisms were negligible and no detectable light adaptation was produced by the stimulus. Lowering the extracellular calcium concentration increased the amplitude and the duration of the response. Raising the extracellular calcium concentration produced the opposite effects. Changing the extracellular calcium concentration modified the response without altering either the linearity of the intensity--response relation or the resting membrane potential in the dark. Light adaptation decreased the amplitude and the duration of the response in a manner that could be quantitatively simulated, in the same photoreceptors, by an increase in the extracellular calcium concentration. Changing the extracellular calcium concentration, or light-adapting the preparation, modified the response without altering its early depolarizing phase. Lowering external calcium either did not affect, or slightly increased, the maximum rate of the light-induced depolarization; raising external calcium, or light-adapting the preparation, either did not affect, or slightly decreased, the maximum rate of the light-induced depolarization. The experimental data can be quantitatively described by a mathematical model with the basic assumption that calcium acts in the process of light adaptation by decreasing the mean open time of the light-activated channels.

  14. Effects of extracellular calcium and of light adaptation on the response to dim light in honey bee drone photoreceptors.

    PubMed Central

    Raggenbass, M

    1983-01-01

    Light responses in honey bee drone photoreceptors were recorded with intracellular micro-electrodes in superfused slices of retina. The effects of changes in extracellular calcium on the size and the shape of the response to dim light were studied and compared with the effects of light adaptation. Dim light stimuli were used so that the amplitude of the response was linearly related to the number of the photons absorbed, the effects of voltage-dependent mechanisms were negligible and no detectable light adaptation was produced by the stimulus. Lowering the extracellular calcium concentration increased the amplitude and the duration of the response. Raising the extracellular calcium concentration produced the opposite effects. Changing the extracellular calcium concentration modified the response without altering either the linearity of the intensity--response relation or the resting membrane potential in the dark. Light adaptation decreased the amplitude and the duration of the response in a manner that could be quantitatively simulated, in the same photoreceptors, by an increase in the extracellular calcium concentration. Changing the extracellular calcium concentration, or light-adapting the preparation, modified the response without altering its early depolarizing phase. Lowering external calcium either did not affect, or slightly increased, the maximum rate of the light-induced depolarization; raising external calcium, or light-adapting the preparation, either did not affect, or slightly decreased, the maximum rate of the light-induced depolarization. The experimental data can be quantitatively described by a mathematical model with the basic assumption that calcium acts in the process of light adaptation by decreasing the mean open time of the light-activated channels. PMID:6655592

  15. Dim light at night interferes with the development of the short-day phenotype and impairs cell-mediated immunity in Siberian hamsters (Phodopus sungorus).

    PubMed

    Aubrecht, Taryn G; Weil, Zachary M; Nelson, Randy J

    2014-10-01

    Winter is a challenging time to survive and breed outside of the tropics. Animals use day length (photoperiod) to regulate seasonally appropriate adaptations in anticipation of challenging winter conditions. The net result of these photoperiod-mediated adjustments is enhanced immune function and increased survival. Thus, the ability to discriminate day length information is critical for survival and reproduction in small animals. However, during the past century, urban and suburban development has rapidly expanded and filled the night sky with light from various sources, obscuring crucial light-dark signals, which alters physiological interpretation of day lengths. Furthermore, reduced space, increased proximity to people, and the presence of light at night may act as stressors for small animals. Whereas acute stressors typically enhance immune responses, chronic exposure to stressors often impairs immune responses. Therefore, we hypothesized that the combination of dim light at night and chronic stress interferes with enhanced cell-mediated immunity observed during short days. Siberian hamsters (Phodopus sungorus) were assigned to short or long days with dark nights (0 lux) or dim (5 lux) light at night for 10 weeks. Following 2 weeks of chronic restraint (6 hr/day), a model of chronic stress, delayed type hypersensitivity (DTH) responses were assessed. Both dim light at night and restraint reduced the DTH response. Dim light at night during long nights produced an intermediate short day phenotype. These results suggest the constant presence of light at night could negatively affect survival of photoperiodic rodents by disrupting the timing of breeding and immune responses.

  16. Identification of blaOXA-51, blaOXA-58, blaDIM-1 and blaVIM carbapenemase genes in hospital enterobacteriaceae isolates from Sierra Leone

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We describe the results of a molecular epidemiological survey of 15 carbapenemase-encoding genes from a recent collection of clinical isolates. The most salient findings revealed that (i) 60% of the isolates harbored multiple carbapenemase genes, (ii) the blaDIM-1 gene that has only been reported in...

  17. ENVIRONMENTAL TECHNOLOGY VERIFICATION, TEST REPORT OF CONTROL OF BIOAEROSOLS IN HVAC SYSTEMS: TRI-DIM FILTER CORP. PREDATOR II MODEL 8VADTP123C23

    EPA Science Inventory

    The Environmental Technology Verification report discusses the technology and performance of the Predator II, Model 8VADTP123C23CC000 air filter for dust and bioaerosol filtration manufactured by Tri-Dim Filter Corporation. The pressure drop across the filter was 138 Pa clean and...

  18. Gr-1dimCD11b+ Immature Myeloid-Derived Suppressor Cells, but not Neutrophils, are Markers of Lethal Tuberculosis Infection in Mice

    PubMed Central

    Tsiganov, Evgeny N.; Verbina, Elena M.; Radaeva, Tatyana V.; Sosunov, Vasily V.; Kosmiadi, George A.; Nikitina, Irina Yu.; Lyadova, Irina V.

    2014-01-01

    Tuberculosis disease (TB) may progress at different rates and have different outcomes. Neutrophils have been implicated in TB progression; however, data on their role during TB are controversial. Here we show that in mice, TB progression is associated with the accumulation of cells that express neutrophilic markers Gr-1 and Ly-6G, but do not belong to conventional neutrophils. The cells exhibit unsegmented nuclei, have Gr-1dimLy-6GdimCD11b+ phenotype and express F4/80, CD49d, Ly-6C, CD117, CD135 markers characteristic not of neutrophils, but of immature myeloid cells. The cells accumulate in the lungs, bone marrow, spleen and blood at the advanced (pre-lethal) stage of M. tuberculosis infection and represent a heterogeneous population of myeloid cells at different stages of their differentiation. The accumulation of Gr-1dimCD11b+ cells is accompanied by the disappearance of conventional neutrophils (Gr-1hiLy-6Ghi-expressing cells). The Gr-1dimCD11b+ cells suppress T cell proliferation and IFN-γ production in vitro via NO-dependent mechanisms, i.e. they exhibit characteristics of myeloid-derived suppressor cells (MDSCs). These results document the generation of MDSCs during TB, suggesting their role in TB pathogenesis, and arguing that neutrophils do not contribute to TB pathology at the advanced disease stage. PMID:24711621

  19. Effects of forward and backward transitions in light intensities in tau-illuminance curves of the rat motor activity rhythm under constant dim light.

    PubMed

    Cambras, Trinitat; Díez-Noguera, Antoni

    2012-07-01

    Circadian rhythms are strongly influenced by light intensity, the effects of which may persist beyond the duration of light exposure (aftereffects). Here, the authors constructed period-illuminance curves for the motor activity circadian rhythm of male and female rats by recording the effects of a series of small upward and downward steps in light intensity (illuminance ranging between .01 lux of dim red light and 1 lux of white light) on their activity. In all cases, stepwise changes were made in five logarithmic steps (irradiance: dim red light: .692 µW/cm(2) and white light: .006, .016, .044, .12, and .315 µW/cm(2), corresponding, respectively, to .02, .05, .14, .13, and 1 lux measured at cage level), with changes in intensity every 2 wks. One group of rats (DLD) started in dim red light, moved up to 1 lux white light, and then back down to the original light intensity. Another group (LDL) started at 1 lux, moved down to .01 lux, and then back up to the original intensity. Motor activity data were recorded throughout the experiment and tau values, the percentage of variance explained by the rhythm, and the mean motor activity for each stage and group were calculated. The results show differences in the dynamics of tau values between the DLD and LDL groups and between males and females. In the LDL group, the tau values of both males and females were dependent on light intensity, and were similar for the forward and backward transitions. In other words, no aftereffects were found, and no differences were detected between males and females. In the DLD group, however, differences were found between males and females. Males had a tau value of 24 h 20 min under dim red light, 25 h 40 min under 1 lux, and 24 h 50 min on return to dim red light. It is noticeable that the tau values of the backward branch of the illuminance curve contradicted classical predictions, since at .38 and .14 lux the tau values were shorter than those found under the same intensities after

  20. Epigenetic silencing of miR-34a in human prostate cancer cells and tumor tissue specimens can be reversed by BR-DIM treatment

    PubMed Central

    Kong, Dejuan; Heath, Elisabeth; Chen, Wei; Cher, Michael; Powell, Isaac; Heilbrun, Lance; Li, Yiwei; Ali, Shadan; Sethi, Seema; Hassan, Oudai; Hwang, Clara; Gupta, Nilesh; Chitale, Dhananjay; Sakr, Wael A; Menon, Mani; Sarkar, Fazlul H

    2012-01-01

    Androgen Receptor (AR) signaling is critically important during the development and progression of prostate cancer (PCa). The AR signaling is also important in the development of castrate resistant prostate cancer (CRPC) where AR is functional even after androgen deprivation therapy (ADT); however, little is known regarding the transcriptional and functional regulation of AR in PCa. Moreover, treatment options for primary PCa for preventing the occurrence of CRPC is limited; therefore, novel strategy for direct inactivation of AR is urgently needed. In this study, we found loss of miR-34a, which targets AR, in PCa tissue specimens, especially in patients with higher Gleason grade tumors, consistent with increased expression of AR. Forced overexpression of miR-34a in PCa cell lines led to decreased expression of AR and prostate specific antigen (PSA) as well as the expression of Notch-1, another important target of miR-34a. Most importantly, BR-DIM intervention in PCa patients prior to radical prostatectomy showed re-expression of miR-34a, which was consistent with decreased expression of AR, PSA and Notch-1 in PCa tissue specimens. Moreover, BR-DIM intervention led to nuclear exclusion both in PCa cell lines and in tumor tissues. PCa cells treated with BR-DIM and 5-aza-dC resulted in the demethylation of miR-34a promoter concomitant with inhibition of AR and PSA expression in LNCaP and C4-2B cells. These results suggest, for the first time, epigenetic silencing of miR -34a in PCa, which could be reversed by BR-DIM treatment and, thus BR-DIM could be useful for the inactivation of AR in the treatment of PCa. PMID:22347519

  1. Epigenetic silencing of miR-34a in human prostate cancer cells and tumor tissue specimens can be reversed by BR-DIM treatment

    PubMed Central

    Kong, D; Heath, E; Chen, W; Cher, M; Powell, I; Heilbrun, L; Li, Y; Ali, S; Sethi, S; Hassan, O; Hwang, C; Gupta, N; Chitale, D; Sakr, WA; Menon, M; Sarkar, FH

    2014-01-01

    Androgen Receptor (AR) signaling is critically important during the development and progression of prostate cancer (PCa). The AR signaling is also important in the development of castrate resistant prostate cancer (CRPC) where AR is functional even after androgen deprivation therapy (ADT); however, little is known regarding the transcriptional and functional regulation of AR in PCa. Moreover, treatment options for primary PCa for preventing the occurrence of CRPC is limited; therefore, novel strategy for direct inactivation of AR is urgently needed. In this study, we found loss of miR-34a, which targets AR, in PCa tissue specimens, especially in patients with higher Gleason grade tumors, consistent with increased expression of AR. Forced over-expression of miR-34a in PCa cell lines led to decreased expression of AR and prostate specific antigen (PSA) as well as the expression of Notch-1, another important target of miR-34a. Most importantly, BR-DIM intervention in PCa patients prior to radical prostatectomy showed reexpression of miR-34a, which was consistent with decreased expression of AR, PSA and Notch-1 in PCa tissue specimens. Moreover, BR-DIM intervention led to nuclear exclusion both in PCa cell lines and in tumor tissues. PCa cells treated with BR-DIM and 5-aza-dC resulted in the demethylation of miR-34a promoter concomitant with inhibition of AR and PSA expression in LNCaP and C4-2B cells. These results suggest, for the first time, epigenetic silencing of miR-34a in PCa, which could be reversed by BR-DIM treatment and, thus BR-DIM could be useful for the inactivation of AR in the treatment of PCa. PMID:24349627

  2. Fluorescence Lifetime Imaging of Apoptosis

    PubMed Central

    Xiao, Annie; Gibbons, Anne E.; Luker, Kathryn E.; Luker, Gary D.

    2015-01-01

    Genetically-encoded fluorescence resonance energy transfer (FRET) reporters are powerful tools to analyze cell signaling and function at single cell resolution in standard two-dimensional cell cultures, but these reporters rarely have been applied to three-dimensional environments. FRET interactions between donor and acceptor molecules typically are determined by changes in relative fluorescence intensities, but wavelength-dependent differences in absorption of light complicate this analysis method in three-dimensional settings. Here we report fluorescence lifetime imaging microscopy (FLIM) with phasor analysis, a method that displays fluorescence lifetimes on a pixel-wise basis in real time, to quantify apoptosis in breast cancer cells stably expressing a genetically encoded FRET reporter. This microscopic imaging technology allowed us to identify treatment-induced apoptosis in single breast cancer cells in environments ranging from two-dimensional cell culture, spheroids with cancer and bone marrow stromal cells, and living mice with orthotopic human breast cancer xenografts. Using this imaging strategy, we showed that combined metabolic therapy targeting glycolysis and glutamine pathways significantly reduced overall breast cancer metabolism and induced apoptosis. We also determined that distinct subpopulations of bone marrow stromal cells control resistance of breast cancer cells to chemotherapy, suggesting heterogeneity of treatment responses of malignant cells in different bone marrow niches. Overall, this study establishes FLIM with phasor analysis as an imaging tool for apoptosis in cell-based assays and living mice, enabling real-time, cellular-level assessment of treatment efficacy and heterogeneity. PMID:26771007

  3. Molecules for Fluorescence Detection of Specific Chemicals

    NASA Technical Reports Server (NTRS)

    Fedor, Steve

    2008-01-01

    A family of fluorescent dye molecules has been developed for use in on-off fluorescence detection of specific chemicals. By themselves, these molecules do not fluoresce. However, when exposed to certain chemical analytes in liquid or vapor forms, they do fluoresce (see figure). These compounds are amenable to fixation on or in a variety of substrates for use in fluorescence-based detection devices: they can be chemically modified to anchor them to porous or non-porous solid supports or can be incorporated into polymer films. Potential applications for these compounds include detection of chemical warfare agents, sensing of acidity or alkalinity, and fluorescent tagging of proteins in pharmaceutical research and development. These molecules could also be exploited for use as two-photon materials for photodynamic therapy in the treatment of certain cancers and other diseases. A molecule in this family consists of a fluorescent core (such as an anthracene or pyrene) attached to two end groups that, when the dye is excited by absorption of light, transfer an electron to the core, thereby quenching the fluorescence. The end groups can be engineered so that they react chemically with certain analytes. Upon reaction, electrons on the end groups are no longer available for transfer to the core and, consequently, the fluorescence from the core is no longer quenched. The chemoselectivity of these molecules can be changed by changing the end groups. For example, aniline end groups afford a capability for sensing acids or acid halides (including those contained in chemical warfare agents). Pyridine or bipyridyl end groups would enable sensing of metal ions. Other chemicals that can be selectively detected through suitable choice of end groups include glucose and proteins. Moreover, the fluorescent cores can be changed to alter light-absorption and -emission characteristics: anthracene cores fluoresce at wavelengths around 500 nm, whereas perylene cores absorb and emit at

  4. The molecular origin and evolution of dim-light vision in mammals.

    PubMed

    Bickelmann, Constanze; Morrow, James M; Du, Jing; Schott, Ryan K; van Hazel, Ilke; Lim, Steve; Müller, Johannes; Chang, Belinda S W

    2015-11-01

    The nocturnal origin of mammals is a longstanding hypothesis that is considered instrumental for the evolution of endothermy, a potential key innovation in this successful clade. This hypothesis is primarily based on indirect anatomical inference from fossils. Here, we reconstruct the evolutionary history of rhodopsin--the vertebrate visual pigment mediating the first step in phototransduction at low-light levels--via codon-based model tests for selection, combined with gene resurrection methods that allow for the study of ancient proteins. Rhodopsin coding sequences were reconstructed for three key nodes: Amniota, Mammalia, and Theria. When expressed in vitro, all sequences generated stable visual pigments with λMAX values similar to the well-studied bovine rhodopsin. Retinal release rates of mammalian and therian ancestral rhodopsins, measured via fluorescence spectroscopy, were significantly slower than those of the amniote ancestor, indicating altered molecular function possibly related to nocturnality. Positive selection along the therian branch suggests adaptive evolution in rhodopsin concurrent with therian ecological diversification events during the Mesozoic that allowed for an exploration of the environment at varying light levels.

  5. The molecular origin and evolution of dim-light vision in mammals.

    PubMed

    Bickelmann, Constanze; Morrow, James M; Du, Jing; Schott, Ryan K; van Hazel, Ilke; Lim, Steve; Müller, Johannes; Chang, Belinda S W

    2015-11-01

    The nocturnal origin of mammals is a longstanding hypothesis that is considered instrumental for the evolution of endothermy, a potential key innovation in this successful clade. This hypothesis is primarily based on indirect anatomical inference from fossils. Here, we reconstruct the evolutionary history of rhodopsin--the vertebrate visual pigment mediating the first step in phototransduction at low-light levels--via codon-based model tests for selection, combined with gene resurrection methods that allow for the study of ancient proteins. Rhodopsin coding sequences were reconstructed for three key nodes: Amniota, Mammalia, and Theria. When expressed in vitro, all sequences generated stable visual pigments with λMAX values similar to the well-studied bovine rhodopsin. Retinal release rates of mammalian and therian ancestral rhodopsins, measured via fluorescence spectroscopy, were significantly slower than those of the amniote ancestor, indicating altered molecular function possibly related to nocturnality. Positive selection along the therian branch suggests adaptive evolution in rhodopsin concurrent with therian ecological diversification events during the Mesozoic that allowed for an exploration of the environment at varying light levels. PMID:26536060

  6. Gold nanoparticle cluster-plasmon-enhanced fluorescent silica core-shell nanoparticles for X-ray computed tomography-fluorescence dual-mode imaging of tumors.

    PubMed

    Hayashi, Koichiro; Nakamura, Michihiro; Miki, Hirokazu; Ozaki, Shuji; Abe, Masahiro; Matsumoto, Toshio; Ishimura, Kazunori

    2013-06-11

    Owing to the surface plasmon resonance-enhanced electromagnetic field, clustered gold nanoparticles-fluorescent silica core-shell nanoparticles became excited within the therapeutic window and fluoresced strongly in this window. The nanoparticles enabled tumor detection using fluorescence imaging and X-ray computed tomography.

  7. Enabling Space Science and Exploration

    NASA Technical Reports Server (NTRS)

    Weber, William J.

    2006-01-01

    This viewgraph presentation on enabling space science and exploration covers the following topics: 1) Today s Deep Space Network; 2) Next Generation Deep Space Network; 3) Needed technologies; 4) Mission IT and networking; and 5) Multi-mission operations.

  8. Computer Security Systems Enable Access.

    ERIC Educational Resources Information Center

    Riggen, Gary

    1989-01-01

    A good security system enables access and protects information from damage or tampering, but the most important aspects of a security system aren't technical. A security procedures manual addresses the human element of computer security. (MLW)

  9. Expansion Microscopy with Conventional Antibodies and Fluorescent Proteins

    PubMed Central

    Chozinski, Tyler J.; Halpern, Aaron R.; Okawa, Haruhisa; Kim, Hyeon-Jin; Tremel, Grant J.; Wong, Rachel O.L.; Vaughan, Joshua C.

    2016-01-01

    Expansion microscopy is a recently introduced technique in which fluorophores on fixed specimens are linked to a swellable polymer that is physically expanded to enable super-resolution microscopy with ordinary microscopes. We have developed and characterized new methods for linking fluorophores to the polymer that now enable expansion microscopy with conventional fluorescently-labeled antibodies and fluorescent proteins. Our methods simplify the procedure, expand the palette of compatible labels, and will aid in rapid dissemination of the technique. PMID:27064647

  10. Modulated Chlorophyll "a" Fluorescence: A Tool for Teaching Photosynthesis

    ERIC Educational Resources Information Center

    Marques da Silva, Jorge; Bernardes da Silva, Anabela; Padua, Mario

    2007-01-01

    "In vivo" chlorophyll "a" fluorescence is a key technique in photosynthesis research. The recent release of a low cost, commercial, modulated fluorometer enables this powerful technology to be used in education. Modulated chlorophyll a fluorescence measurement "in vivo" is here proposed as a tool to demonstrate basic photosynthesis phenomena to…

  11. Reactive Fluorescent Dyes For Urethane Coatings

    NASA Technical Reports Server (NTRS)

    Willis, Paul B.; Cuddihy, Edward F.

    1991-01-01

    Molecules of fluorescent dyes chemically bound in urethane conformal-coating materials to enable nondestructive detection of flaws in coats through inspection under ultraviolet light, according to proposal. Dye-bonding technique prevents outgassing of dyes, making coating materials suitable for use where flaw-free coats must be assured in instrumentation or other applications in which contamination by outgassing must be minimized.

  12. Fluorescent Protein Based FRET Pairs with Improved Dynamic Range for Fluorescence Lifetime Measurements.

    PubMed

    George Abraham, Bobin; Sarkisyan, Karen S; Mishin, Alexander S; Santala, Ville; Tkachenko, Nikolai V; Karp, Matti

    2015-01-01

    Fluorescence Resonance Energy Transfer (FRET) using fluorescent protein variants is widely used to study biochemical processes in living cells. FRET detection by fluorescence lifetime measurements is the most direct and robust method to measure FRET. The traditional cyan-yellow fluorescent protein based FRET pairs are getting replaced by green-red fluorescent protein variants. The green-red pair enables excitation at a longer wavelength which reduces cellular autofluorescence and phototoxicity while monitoring FRET. Despite the advances in FRET based sensors, the low FRET efficiency and dynamic range still complicates their use in cell biology and high throughput screening. In this paper, we utilized the higher lifetime of NowGFP and screened red fluorescent protein variants to develop FRET pairs with high dynamic range and FRET efficiency. The FRET variations were analyzed by proteolytic activity and detected by steady-state and time-resolved measurements. Based on the results, NowGFP-tdTomato and NowGFP-mRuby2 have shown high potentials as FRET pairs with large fluorescence lifetime dynamic range. The in vitro measurements revealed that the NowGFP-tdTomato has the highest Förster radius for any fluorescent protein based FRET pairs yet used in biological studies. The developed FRET pairs will be useful for designing FRET based sensors and studies employing Fluorescence Lifetime Imaging Microscopy (FLIM). PMID:26237400

  13. Levels of circulating CD45dimCD34+VEGFR2+ progenitor cells correlate with outcome in metastatic renal cell carcinoma patients treated with tyrosine kinase inhibitors

    PubMed Central

    Farace, F; Gross-Goupil, M; Tournay, E; Taylor, M; Vimond, N; Jacques, N; Billiot, F; Mauguen, A; Hill, C; Escudier, B

    2011-01-01

    Background: Predicting the efficacy of antiangiogenic therapy would be of clinical value in patients (pts) with metastatic renal cell carcinoma (mRCC). We tested the hypothesis that circulating endothelial cell (CEC), bone marrow-derived CD45dimCD34+VEGFR2+ progenitor cell or plasma angiogenic factor levels are associated with clinical outcome in mRCC pts undergoing treatment with tyrosine kinase inhibitors (TKI). Methods: Fifty-five mRCC pts were prospectively monitored at baseline (day 1) and day 14 during treatment (46 pts received sunitinib and 9 pts received sorafenib). Circulating endothelial cells (CD45−CD31+CD146+7-amino-actinomycin (7AAD)− cells) were measured in 1 ml whole blood using four-color flow cytometry (FCM). Circulating CD45dimCD34+VEGFR2+7AAD− progenitor cells were measured in progenitor-enriched fractions by four-color FCM. Plasma VEGF, sVEGFR2, SDF-1α and sVCAM-1 levels were determined by ELISA. Correlations between baseline CEC, CD45dimCD34+VEGFR2+7AAD− progenitor cells, plasma factors, as well as day 1–day 14 changes in CEC, CD45dimCD34+VEGFR2+7AAD− progenitor, plasma factor levels, and response to TKI, progression-free survival (PFS) and overall survival (OS) were examined. Results: No significant correlation between markers and response to TKI was observed. No association between baseline CEC, plasma VEGF, sVEGFR-2, SDF-1α, sVCAM-1 levels with PFS and OS was observed. However, baseline CD45dimCD34+VEGFR2+7AAD− progenitor cell levels were associated with PFS (P=0.01) and OS (P=0.006). Changes in this population and in SDF-1α levels between day 1 and day 14 were associated with PFS (P=0.03, P=0.002). Changes in VEGF and SDF-1α levels were associated with OS (P=0.02, P=0.007). Conclusion: Monitoring CD45dimCD34+VEGFR2+ progenitor cells, plasma VEGF and SDF-1α levels could be of clinical interest in TKI-treated mRCC pts to predict outcome. PMID:21386843

  14. Dust Impact Monitor (SESAME-DIM) on board Rosetta/Philae: Millimetric particle flux at comet 67P/Churyumov-Gerasimenko

    NASA Astrophysics Data System (ADS)

    Hirn, Attila; Albin, Thomas; Apáthy, István; Della Corte, Vincenzo; Fischer, Hans-Herbert; Flandes, Alberto; Loose, Alexander; Péter, Attila; Seidensticker, Klaus J.; Krüger, Harald

    2016-06-01

    Context. The Philae lander of the Rosetta mission, aimed at the in situ investigation of comet 67P/Churyumov-Gerasimenko, was deployed to the surface of the comet nucleus on 12 November 2014 at 2.99 AU heliocentric distance. The Dust Impact Monitor (DIM) as part of the Surface Electric Sounding and Acoustic Monitoring Experiment (SESAME) on the lander employed piezoelectric detectors to detect the submillimetre- and millimetre-sized dust and ice particles emitted from the nucleus. Aims: We determine the upper limit of the ambient flux of particles in the measurement range of DIM based on the measurements performed with the instrument during Philae's descent to its nominal landing site Agilkia at distances of about 22 km, 18 km, and 5 km from the nucleus barycentre and at the final landing site Abydos. Methods: The geometric factor of the DIM sensor was calculated assuming an isotropic ambient flux of the submillimetre- and millimetre-sized particles. For the measurement intervals when no particles were detected the maximum true impact rate was calculated by assuming Poisson distribution of the impacts, and it was given as the detection limit at a 95% confidence level. The shading by the comet environment at Abydos was estimated by simulating the pattern of illumination on Philae and consequently the topography around the lander. Results: Based on measurements performed with DIM, the upper limit of the flux of particles in the measurement range of the instrument was of the order of 10-8-10-7 m-2 s-1 sr-1 during descent. The upper limit of the ambient flux of the submillimetre- and millimetre-sized dust and ice particles at Abydos was estimated to be 1.6 × 10-9 m-2 s-1 sr-1 on 13 and 14 November 2014. A correction factor of roughly 1/3 for the field of view of the sensors was calculated based on an analysis of the pattern of illumination on Philae. Conclusions: Considering particle speeds below escape velocity, the upper limit for the volume density of particles in

  15. New surface solar radiation and evaporation datasets in Spain: in search of a better understating of the dimming/brightening

    NASA Astrophysics Data System (ADS)

    Sanchez-Lorenzo, A.; Calbó, J.; Wild, M.

    2012-04-01

    Previous research on the dimming/brightening phenomena in Spain has been limited to the analysis of the long-term series of sunshine duration (Sanchez-Lorenzo et al., 2007) and cloud cover observations (Sanchez-Lorenzo et al., 2009). This work describes the development of a new dataset of surface radiation in Spain based on the 16 longest daily series provided by the Spanish Meteorology Agency, with the first series starting in the early 1970s, and providing global, diffuse and direct radiation. For the Madrid station an additional effort has been made to digitalize monthly records of global radiation since 1958, which provide the longest series available in Spain up to the present. The results of a temporal analysis of this dataset show an overall agreement with the trends observed using sunshine duration series, confirming the suitability of this latter variable to estimate surface radiation on decadal time scales. The important role of surface solar radiation to drive evaporation is well known, and consequently an agreement between the dimming/brightening phases and the trends in potential evaporation has been observed worldwide (Wild, 2009). Therefore, a dataset consisting of monthly series of potential evaporation has been generated by using records from tanks and Piche atmometers. The pan evaporation data consist of 13 series with records since 1981, meanwhile for Piche measurements there are around 100 series with more than 60 years of data, some of them starting in the beginning of the 20th century. The results show a decrease in pan evaporation (1981-2010 period) that cannot be explained by the observed increase in solar radiation, but may be linked to a decrease in the wind speed. On the other hand, evaporation trends estimated by the Piche evaporimeter provide a better agreement with solar radiation and sunshine time trends. This relationship needs special attention, as Piche evaporimeter is exposed inside a meteorological screen, especially regarding

  16. Genetically Engineered Fluorescent Voltage Reporters

    PubMed Central

    2012-01-01

    Fluorescent membrane voltage indicators that enable optical imaging of neuronal circuit operations in the living mammalian brain are powerful tools for biology and particularly neuroscience. Classical voltage-sensitive dyes, typically low molecular-weight organic compounds, have been in widespread use for decades but are limited by issues related to optical noise, the lack of generally applicable procedures that enable staining of specific cell populations, and difficulties in performing imaging experiments over days and weeks. Genetically encoded voltage indicators (GEVIs) represent a newer alternative that overcomes several of the limitations inherent to classical voltage-sensitive dyes. We critically review the fundamental concepts of this approach, the variety of available probes and their state of development. PMID:22896802

  17. A Fluorescence Lecture Demonstration.

    ERIC Educational Resources Information Center

    Bozzelli, Joseph W.; Kemp, Marwin

    1982-01-01

    Describes fluorescence demonstrations related to several aspects of molecular theory and quantitized energy levels. Demonstrations use fluorescent chemical solutions having luminescence properties spanning the visible spectrum. Also describes a demonstration of spontaneous combustion of familiar substances in chlorine. (JN)

  18. Fluorescent optical position sensor

    DOEpatents

    Weiss, Jonathan D.

    2005-11-15

    A fluorescent optical position sensor and method of operation. A small excitation source side-pumps a localized region of fluorescence at an unknown position along a fluorescent waveguide. As the fluorescent light travels down the waveguide, the intensity of fluorescent light decreases due to absorption. By measuring with one (or two) photodetectors the attenuated intensity of fluorescent light emitted from one (or both) ends of the waveguide, the position of the excitation source relative to the waveguide can be determined by comparing the measured light intensity to a calibrated response curve or mathematical model. Alternatively, excitation light can be pumped into an end of the waveguide, which generates an exponentially-decaying continuous source of fluorescent light along the length of the waveguide. The position of a photodetector oriented to view the side of the waveguide can be uniquely determined by measuring the intensity of the fluorescent light emitted radially at that location.

  19. Multiple frequency fluorescence lifetime imaging microscopy.

    PubMed

    Squire, A; Verveer, P J; Bastiaens, P I

    2000-02-01

    The experimental configuration and the computational algorithms for performing multiple frequency fluorescence lifetime imaging microscopy (mfFLIM) are described. The mfFLIM experimental set-up enables the simultaneous homodyne detection of fluorescence emission modulated at a set of harmonic frequencies. This was achieved in practice by using monochromatic laser light as an excitation source modulated at a harmonic set of frequencies. A minimum of four frequencies were obtained by the use of two standing wave acousto-optic modulators placed in series. Homodyne detection at each of these frequencies was performed simultaneously by mixing with matching harmonics present in the gain characteristics of a microchannel plate (MCP) image intensifier. These harmonics arise as a natural consequence of applying a high frequency sinusoidal voltage to the photocathode of the device, which switches the flow of photoelectrons 'on' and 'off' as the sinus voltage swings from negative to positive. By changing the bias of the sinus it was possible to control the duration of the 'on' state of the intensifier relative to its 'off' state, enabling the amplitude of the higher harmonic content in the gain to be controlled. Relative modulation depths of 400% are theoretically possible from this form of square-pulse modulation. A phase-dependent integrated image is formed by the sum of the mixed frequencies on the phosphor of the MCP. Sampling this signal over a full period of the fundamental harmonic enables each harmonic to be resolved, provided that the Nyquist sampling criterion is satisfied for the highest harmonic component in the signal. At each frequency both the phase and modulation parameters can be estimated from a Fourier analysis of the data. These parameters enable the fractional populations and fluorescence lifetimes of individual components of a complex fluorescence decay to be resolved on a pixel-by-pixel basis using a non-linear fit to the dispersion relationships. The

  20. Atmospheric Nitrogen Fluorescence Yield

    NASA Technical Reports Server (NTRS)

    Adams, J. H., Jr.; Christl, M. J.; Fountain, W. F.; Gregory, J. C.; Martens, K. U.; Sokolsky, Pierre; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    Several existing and planned experiments estimate the energies of ultra-high energy cosmic rays from air showers using the atmospheric nitrogen fluorescence. The nitrogen fluorescence yield from air shower electrons depends on the atmospheric composition. We will discuss the uncertainties in the fluorescence yield form electrons in the real atmosphere and describe a concept for a small balloon payload to measure the atmospheric fluorescence yield as a function of attitude.

  1. Safe biodegradable fluorescent particles

    DOEpatents

    Martin, Sue I.; Fergenson, David P.; Srivastava, Abneesh; Bogan, Michael J.; Riot, Vincent J.; Frank, Matthias

    2010-08-24

    A human-safe fluorescence particle that can be used for fluorescence detection instruments or act as a safe simulant for mimicking the fluorescence properties of microorganisms. The particle comprises a non-biological carrier and natural fluorophores encapsulated in the non-biological carrier. By doping biodegradable-polymer drug delivery microspheres with natural or synthetic fluorophores, the desired fluorescence can be attained or biological organisms can be simulated without the associated risks and logistical difficulties of live microorganisms.

  2. Pulsed-light imaging for fluorescence guided surgery under normal room lighting.

    PubMed

    Sexton, Kristian; Davis, Scott C; McClatchy, David; Valdes, Pablo A; Kanick, Stephen C; Paulsen, Keith D; Roberts, David W; Pogue, Brian W

    2013-09-01

    Fluorescence guided surgery (FGS) is an emerging technology that has demonstrated improved surgical outcomes. However, dim lighting conditions required by current FGS systems are disruptive to standard surgical workflow. We present a novel FGS system capable of imaging fluorescence under normal room light by using pulsed excitation and gated acquisition. Images from tissue-simulating phantoms confirm visual detection down to 0.25 μM of protoporphyrin IX under 125 μW/cm2 of ambient light, more than an order of magnitude lower than that measured with the Zeiss Pentero in the dark. Resection of orthotopic brain tumors in mice also suggests that the pulsed-light system provides superior sensitivity in vivo.

  3. Pulsed-light imaging for fluorescence guided surgery under normal room lighting

    PubMed Central

    Sexton, Kristian; Davis, Scott C.; McClatchy, David; Valdes, Pablo A.; Kanick, Stephen C.; Paulsen, Keith D.; Roberts, David W.; Pogue, Brian W.

    2013-01-01

    Fluorescence guided surgery (FGS) is an emerging technology that has demonstrated improved surgical outcomes. However, dim lighting conditions required bycurrent FGS systems are disruptive to standard surgical workflow. We present a novel FGS system capable of imaging fluorescence under normal room lightby using pulsed excitation and gated acquisition. Images from tissue-simulating phantoms confirm visual detection down to 0.25 μM of protopor-phyrin IX under 125 μW/cm2 of ambient light, more than an order of magnitude lower than that measured with the Zeiss Pentero in the dark. Resection of orthotopic brain tumors in mice also suggests that the pulsed-light system provides superior sensitivity in vivo. PMID:23988926

  4. The Drosophila Prosecretory Transcription Factor dimmed Is Dynamically Regulated in Adult Enteroendocrine Cells and Protects Against Gram-Negative Infection.

    PubMed

    Beebe, Katherine; Park, Dongkook; Taghert, Paul H; Micchelli, Craig A

    2015-05-20

    The endocrine system employs peptide hormone signals to translate environmental changes into physiological responses. The diffuse endocrine system embedded in the gastrointestinal barrier epithelium is one of the largest and most diverse endocrine tissues. Furthermore, it is the only endocrine tissue in direct physical contact with the microbial environment of the gut lumen. However, it remains unclear how this sensory epithelium responds to specific pathogenic challenges in a dynamic and regulated manner. We demonstrate that the enteroendocrine cells of the adult Drosophila melanogaster midgut display a transient, sensitive, and systemic induction of the prosecretory factor dimmed (dimm) in response to the Gram-negative pathogen Pseudomonas entomophila (Pe). In enteroendocrine cells, dimm controls the levels of the targets Phm, dcat-4, and the peptide hormone, Allatostatin A. Finally, we identify dimm as a host factor that protects against Pe infection and controls the expression of antimicrobial peptides. We propose that dimm provides "gain" in enteroendocrine output during the adaptive response to episodic pathogen exposure.

  5. The effect of age and pre-light melatonin concentration on the melatonin sensitivity to dim light.

    PubMed

    Nathan, P J; Burrows, G D; Norman, T R

    1999-05-01

    The hormone melatonin is secreted at night from the pineal gland, with light being a potent inhibitor of its secretion. Age related decreases in plasma melatonin concentrations have indicated that this may be related to pineal calcification with aging. Recently, it was shown that the melatonin sensitivity to light may be a biological marker of bipolar disorder. However, on average, patients were older than the control group in most studies, and it is not known if age has an effect on the melatonin suppression by light. To test this hypothesis, the present study investigated the effect of age on the melatonin sensitivity to dim light (200 lux). Participants were grouped into three age groups. On the testing night, they were placed in a dark room from 21.00 h to 02.30 h. Light exposure was for an hour from midnight to 01.00 h. Blood samples were collected at regular intervals for measurement of plasma melatonin. No significant differences were found in the percentage suppression of melatonin within the age groups defined in the present study (P > 0.5). No correlation was also found between age and percentage suppression of melatonin (r2 = 0.007; P > 0.1). Our results suggest that the melatonin suppression by light (200 lux) is not affected by age. PMID:10435774

  6. Genome-wide features of neuroendocrine regulation in Drosophila by the basic helix-loop-helix transcription factor DIMMED

    PubMed Central

    Hadžić, Tarik; Park, Dongkook; Abruzzi, Katharine C.; Yang, Lin; Trigg, Jennifer S.; Rohs, Remo; Rosbash, Michael; Taghert, Paul H.

    2015-01-01

    Neuroendocrine (NE) cells use large dense core vesicles (LDCVs) to traffic, process, store and secrete neuropeptide hormones through the regulated secretory pathway. The dimmed (DIMM) basic helix-loop-helix transcription factor of Drosophila controls the level of regulated secretory activity in NE cells. To pursue its mechanisms, we have performed two independent genome-wide analyses of DIMM's activities: (i) in vivo chromatin immunoprecipitation (ChIP) to define genomic sites of DIMM occupancy and (ii) deep sequencing of purified DIMM neurons to characterize their transcriptional profile. By this combined approach, we showed that DIMM binds to conserved E-boxes in enhancers of 212 genes whose expression is enriched in DIMM-expressing NE cells. DIMM binds preferentially to certain E-boxes within first introns of specific gene isoforms. Statistical machine learning revealed that flanking regions of putative DIMM binding sites contribute to its DNA binding specificity. DIMM's transcriptional repertoire features at least 20 LDCV constituents. In addition, DIMM notably targets the pro-secretory transcription factor, creb-A, but significantly, DIMM does not target any neuropeptide genes. DIMM therefore prescribes the scale of secretory activity in NE neurons, by a systematic control of both proximal and distal points in the regulated secretory pathway. PMID:25634895

  7. Divergence of dim-light vision among bats (order: Chiroptera) as estimated by molecular and electrophysiological methods.

    PubMed

    Liu, He-Qun; Wei, Jing-Kuan; Li, Bo; Wang, Ming-Shan; Wu, Rui-Qi; Rizak, Joshua D; Zhong, Li; Wang, Lu; Xu, Fu-Qiang; Shen, Yong-Yi; Hu, Xin-Tian; Zhang, Ya-Ping

    2015-06-23

    Dim-light vision is present in all bats, but is divergent among species. Old-World fruit bats (Pteropodidae) have fully developed eyes; the eyes of insectivorous bats are generally degraded, and these bats rely on well-developed echolocation. An exception is the Emballonuridae, which are capable of laryngeal echolocation but prefer to use vision for navigation and have normal eyes. In this study, integrated methods, comprising manganese-enhanced magnetic resonance imaging (MEMRI), f-VEP and RNA-seq, were utilized to verify the divergence. The results of MEMRI showed that Pteropodidae bats have a much larger superior colliculus (SC)/ inferior colliculus (IC) volume ratio (3:1) than insectivorous bats (1:7). Furthermore, the absolute visual thresholds (log cd/m(2)•s) of Pteropodidae (-6.30 and -6.37) and Emballonuridae (-3.71) bats were lower than those of other insectivorous bats (-1.90). Finally, genes related to the visual pathway showed signs of positive selection, convergent evolution, upregulation and similar gene expression patterns in Pteropodidae and Emballonuridae bats. Different results imply that Pteropodidae and Emballonuridae bats have more developed vision than the insectivorous bats and suggest that further research on bat behavior is warranted.

  8. Polarized thermal emission from X-ray dim isolated neutron stars: the case of RX J1856.5-3754

    NASA Astrophysics Data System (ADS)

    González Caniulef, D.; Zane, S.; Taverna, R.; Turolla, R.; Wu, K.

    2016-07-01

    The observed polarization properties of thermal radiation from isolated, cooling neutron stars depend on both the emission processes at the surface and the effects of the magnetized vacuum which surrounds the star. Here, we investigate the polarized thermal emission from X-ray dim isolated neutron stars, taking RX J1856.5-3754 as a representative case. The physical conditions of the star outermost layers in these sources is still debated, and so we consider emission from a magnetized atmosphere and a condensed surface, accounting for the effects of vacuum polarization as the radiation propagates in the star magnetosphere. We have found that, for a significant range of viewing geometries, measurement of the phase-averaged polarization fraction and phase-averaged polarization angle at both optical and X-ray wavelengths allow us to determine whether this neutron star has an atmosphere or a condensed surface. Our results may therefore be relevant in view of future developments of soft X-ray polarimeters.

  9. Why the dim light melatonin onset (DLMO) should be measured before treatment of patients with circadian rhythm sleep disorders.

    PubMed

    Keijzer, Henry; Smits, Marcel G; Duffy, Jeanne F; Curfs, Leopold M G

    2014-08-01

    Treatment of circadian rhythm sleep disorders (CRSD) may include light therapy, chronotherapy and melatonin. Exogenous melatonin is increasingly being used in patients with insomnia or CRSD. Although pharmacopoeias and the European food safety authority (EFSA) recommend administering melatonin 1-2 h before desired bedtime, several studies have shown that melatonin is not always effective if administered according to that recommendation. Crucial for optimal treatment of CRSD, melatonin and other treatments should be administered at a time related to individual circadian timing (typically assessed using the dim light melatonin onset (DLMO)). If not administered according to the individual patient's circadian timing, melatonin and other treatments may not only be ineffective, they may even result in contrary effects. Endogenous melatonin levels can be measured reliably in saliva collected at the patient's home. A clinically reliably DLMO can be calculated using a fixed threshold. Diary and polysomnographic sleep-onset time do not reliably predict DLMO or circadian timing in patients with CRSD. Knowing the patient's individual circadian timing by assessing DLMO can improve diagnosis and treatment of CRSD with melatonin as well as other therapies such as light or chronotherapy, and optimizing treatment timing will shorten the time required to achieve results.

  10. Modeling the Quality of Videos Displayed With Local Dimming Backlight at Different Peak White and Ambient Light Levels.

    PubMed

    Mantel, Claire; Sogaard, Jacob; Bech, Soren; Korhonen, Jari; Pedersen, Jesper Melgaard; Forchhammer, Soren

    2016-08-01

    This paper investigates the impact of ambient light and peak white (maximum brightness of a display) on the perceived quality of videos displayed using local backlight dimming. Two subjective tests providing quality evaluations are presented and analyzed. The analyses of variance show significant interactions of the factors peak white and ambient light with the perceived quality. Therefore, we proceed to predict the subjective quality grades with objective measures. The rendering of the frames on liquid crystal displays with light emitting diodes backlight at various ambient light and peak white levels is computed using a model of the display. Widely used objective quality metrics are applied based on the rendering models of the videos to predict the subjective evaluations. As these predictions are not satisfying, three machine learning methods are applied: partial least square regression, elastic net, and support vector regression. The elastic net method obtains the best prediction accuracy with a spearman rank order correlation coefficient of 0.71, and two features are identified as having a major influence on the visual quality.

  11. Divergence of dim-light vision among bats (order: Chiroptera) as estimated by molecular and electrophysiological methods.

    PubMed

    Liu, He-Qun; Wei, Jing-Kuan; Li, Bo; Wang, Ming-Shan; Wu, Rui-Qi; Rizak, Joshua D; Zhong, Li; Wang, Lu; Xu, Fu-Qiang; Shen, Yong-Yi; Hu, Xin-Tian; Zhang, Ya-Ping

    2015-01-01

    Dim-light vision is present in all bats, but is divergent among species. Old-World fruit bats (Pteropodidae) have fully developed eyes; the eyes of insectivorous bats are generally degraded, and these bats rely on well-developed echolocation. An exception is the Emballonuridae, which are capable of laryngeal echolocation but prefer to use vision for navigation and have normal eyes. In this study, integrated methods, comprising manganese-enhanced magnetic resonance imaging (MEMRI), f-VEP and RNA-seq, were utilized to verify the divergence. The results of MEMRI showed that Pteropodidae bats have a much larger superior colliculus (SC)/ inferior colliculus (IC) volume ratio (3:1) than insectivorous bats (1:7). Furthermore, the absolute visual thresholds (log cd/m(2)•s) of Pteropodidae (-6.30 and -6.37) and Emballonuridae (-3.71) bats were lower than those of other insectivorous bats (-1.90). Finally, genes related to the visual pathway showed signs of positive selection, convergent evolution, upregulation and similar gene expression patterns in Pteropodidae and Emballonuridae bats. Different results imply that Pteropodidae and Emballonuridae bats have more developed vision than the insectivorous bats and suggest that further research on bat behavior is warranted. PMID:26100095

  12. Bilinear weighting and threshold scheme for low-power two-dimensional local dimming liquid crystal displays without block artifacts

    NASA Astrophysics Data System (ADS)

    Kim, Seul-Ki; Song, Seok-Jeong; Nam, Hyoungsik

    2014-06-01

    A two-dimensional (2-D) weighted roll-off local dimming algorithm that eliminates any visible block artifacts caused by the spatial mismatch between a discontinuous panel image and a continuous backlight is described. The proposed scheme enhances the high gray details by means of a roll-off scheme and removes the block artifacts with bilinear weighting of a pixel-compensated panel image. In addition, the threshold scheme is used to resolve overcompensation problems that lead to visible artifacts around the boundaries of dark local blocks. The image quality and the power consumption are evaluated for 40 test images through both simulation and measurement. Compared to 15.56 and 1.45 of a 2-D roll-off method, the maximum and average color difference values of a proposed scheme are reduced to 7.76 and 0.72 in the simulation. For a prototype 40-in. light emitting diode TV, the average power saving over 40 test images is measured as 60.96%.

  13. Blinking triggered by the change in the solvent accessibility of a fluorescent molecule.

    PubMed

    Kawai, Kiyohiko; Koshimo, Takeshi; Maruyama, Atsushi; Majima, Tetsuro

    2014-09-18

    The more a fluorescent molecule is exposed to a solvent, the faster its triplet excited state is quenched by molecular oxygen. The changes in the solvent accessibility of a fluorescent molecule were probed by measuring the duration of the off time during the blinking of the fluorescence, which enabled analysis of the function of a molecular beacon-type probe.

  14. Enabling the Differently-Abled

    ERIC Educational Resources Information Center

    Pal, Sonali

    2009-01-01

    It is perhaps unfortunate that enabling technologies do not come with an "ability warning", as they generally require the user to already have acquired a certain level of IT skills, in a similar way that online courses require users to have a certain level of prior IT knowledge. Accessing a computer and making the most of e-learning…

  15. Enable: Developing Instructional Language Skills.

    ERIC Educational Resources Information Center

    Witt, Beth

    The program presented in this manual provides a structure and activities for systematic development of effective listening comprehension in typical and atypical children. The complete ENABLE kit comes with pictures, cut-outs, and puppets to illustrate the directives, questions, and narrative activities. The manual includes an organizational and…

  16. Detection of dimming/brightening in Italy from homogenized all-sky and clear-sky surface solar radiation records and underlying causes (1959-2013)

    NASA Astrophysics Data System (ADS)

    Manara, Veronica; Brunetti, Michele; Celozzi, Angela; Maugeri, Maurizio; Sanchez-Lorenzo, Arturo; Wild, Martin

    2016-09-01

    A dataset of 54 daily Italian downward surface solar radiation (SSR) records has been set up collecting data for the 1959-2013 period. Special emphasis is given to the quality control and the homogenization of the records in order to ensure the reliability of the resulting trends. This step has been shown as necessary due to the large differences obtained between the raw and homogenized dataset, especially during the first decades of the study period. In addition, SSR series under clear-sky conditions were obtained considering only the cloudless days from corresponding ground-based cloudiness observations. Subsequently, records were interpolated onto a regular grid and clustered into two regions, northern and southern Italy, which were averaged in order to get all-sky and clear-sky regional SSR records. Their temporal evolution is presented, and possible reasons for differences between all-sky and clear-sky conditions and between the two regions are discussed in order to determine to what extent SSR variability depends on aerosols or clouds. Specifically, the all-sky SSR records show a decrease until the mid-1980s (dimming period), and a following increase until the end of the series (brightening period) even though strength and persistence of tendencies are not the same in all seasons. Clear-sky records present stronger tendencies than all-sky records during the dimming period in all seasons and during the brightening period in winter and autumn. This suggests that, under all-sky conditions, the variations caused by the increase/decrease in the aerosol content have been partially masked by cloud cover variations, especially during the dimming period. Under clear sky the observed dimming is stronger in the south than in the north. This peculiarity could be a consequence of a significant contribution of mineral dust variations to the SSR variability.

  17. Two-step phase-shifting fluorescence incoherent holographic microscopy

    PubMed Central

    Qin, Wan; Yang, Xiaoqi; Li, Yingying; Peng, Xiang; Yao, Hai; Qu, Xinghua; Gao, Bruce Z.

    2014-01-01

    Abstract. Fluorescence holographic microscope (FINCHSCOPE) is a motionless fluorescence holographic imaging technique based on Fresnel incoherent correlation holography (FINCH) that shows promise in reconstructing three-dimensional fluorescence images of biological specimens with three holograms. We report a developing two-step phase-shifting method that reduces the required number of holograms from three to two. Using this method, we resolved microscopic fluorescent beads that were three-dimensionally distributed at different depths with two interferograms captured by a CCD camera. The method enables the FINCHSCOPE to work in conjunction with the frame-straddling technique and significantly enhance imaging speed. PMID:24972355

  18. Fluorescence study of sugars

    NASA Astrophysics Data System (ADS)

    Thongjamroon, Sunida; Pattanaporkratana, Apichart

    2015-07-01

    We studied photoemission of monosaccharides and disaccharides using laser-induced fluorescence spectroscopy. A 532- nm, 10 mW, laser was used to excite the samples and back-scattering signals were collected by a spectrometer. We found that most sugars show weak fluorescence in solid phase but do not fluoresce when dissolved in water solutions. The emission spectra show similar peak intensity at 590 nm, but they are different in emission intensities. We suggest that the fluorescence spectra may be used to differentiate sugar type, even though the origin of the fluorescence is unclear and needed further study.

  19. Multimodal optoacoustic and multiphoton fluorescence microscopy

    NASA Astrophysics Data System (ADS)

    Sela, Gali; Razansky, Daniel; Shoham, Shy

    2013-03-01

    Multiphoton microscopy is a powerful imaging modality that enables structural and functional imaging with cellular and sub-cellular resolution, deep within biological tissues. Yet, its main contrast mechanism relies on extrinsically administered fluorescent indicators. Here we developed a system for simultaneous multimodal optoacoustic and multiphoton fluorescence 3D imaging, which attains both absorption and fluorescence-based contrast by integrating an ultrasonic transducer into a two-photon laser scanning microscope. The system is readily shown to enable acquisition of multimodal microscopic images of fluorescently labeled targets and cell cultures as well as intrinsic absorption-based images of pigmented biological tissue. During initial experiments, it was further observed that that detected optoacoustically-induced response contains low frequency signal variations, presumably due to cavitation-mediated signal generation by the high repetition rate (80MHz) near IR femtosecond laser. The multimodal system may provide complementary structural and functional information to the fluorescently labeled tissue, by superimposing optoacoustic images of intrinsic tissue chromophores, such as melanin deposits, pigmentation, and hemoglobin or other extrinsic particle or dye-based markers highly absorptive in the NIR spectrum.

  20. An 80 kyr-long continuous speleothem record from Dim Cave, SW Turkey with paleoclimatic implications for the Eastern Mediterranean.

    PubMed

    Ünal-İmer, Ezgi; Shulmeister, James; Zhao, Jian-Xin; Uysal, I Tonguç; Feng, Yue-Xing; Nguyen, Ai Duc; Yüce, Galip

    2015-01-01

    Speleothem-based stable isotope records are valuable in sub-humid and semi-arid settings where many other terrestrial climate proxies are fragmentary. The Eastern Mediterranean is one such region. Here we present an 80-kyr-long precisely-dated (by U-series) and high-resolution oxygen (δ(18)O) and carbon (δ(13)C) records from Dim Cave (~36°N) in SW Turkey. The glacial-interglacial δ(18)O variations in the Dim Cave speleothem are best explained in terms of changes in the trajectories of winter westerly air masses. These are along a northerly (European) track (isotopically less depleted) during the early last glaciation but are gradually depressed southward closer to the modern westerly track along the North African coast (more depleted) after c.50 kyr and remain in the southern track through the Last Glacial Maximum. The southward displacement of the westerly track reflects growth of the Fennoscandian ice sheet and its impact on westerly wind fields. Changes in δ(13)C are interpreted as reflecting soil organic matter composition and/or thickness. δ(13)C values are significantly more negative in interglacials reflecting active carbonic acid production in the soil and less negative in glacial times reflecting carbonate rock values. Several Heinrich events are recorded in the Dim record indicating intensification of westerly flow across this part of the EM.

  1. An 80 kyr-long continuous speleothem record from Dim Cave, SW Turkey with paleoclimatic implications for the Eastern Mediterranean

    PubMed Central

    Ünal-İmer, Ezgi; Shulmeister, James; Zhao, Jian-Xin; Tonguç Uysal, I.; Feng, Yue-Xing; Duc Nguyen, Ai; Yüce, Galip

    2015-01-01

    Speleothem-based stable isotope records are valuable in sub-humid and semi-arid settings where many other terrestrial climate proxies are fragmentary. The Eastern Mediterranean is one such region. Here we present an 80-kyr-long precisely-dated (by U-series) and high-resolution oxygen (δ18O) and carbon (δ13C) records from Dim Cave (~36°N) in SW Turkey. The glacial-interglacial δ18O variations in the Dim Cave speleothem are best explained in terms of changes in the trajectories of winter westerly air masses. These are along a northerly (European) track (isotopically less depleted) during the early last glaciation but are gradually depressed southward closer to the modern westerly track along the North African coast (more depleted) after c.50 kyr and remain in the southern track through the Last Glacial Maximum. The southward displacement of the westerly track reflects growth of the Fennoscandian ice sheet and its impact on westerly wind fields. Changes in δ13C are interpreted as reflecting soil organic matter composition and/or thickness. δ13C values are significantly more negative in interglacials reflecting active carbonic acid production in the soil and less negative in glacial times reflecting carbonate rock values. Several Heinrich events are recorded in the Dim record indicating intensification of westerly flow across this part of the EM. PMID:26337921

  2. An 80 kyr-long continuous speleothem record from Dim Cave, SW Turkey with paleoclimatic implications for the Eastern Mediterranean.

    PubMed

    Ünal-İmer, Ezgi; Shulmeister, James; Zhao, Jian-Xin; Uysal, I Tonguç; Feng, Yue-Xing; Nguyen, Ai Duc; Yüce, Galip

    2015-01-01

    Speleothem-based stable isotope records are valuable in sub-humid and semi-arid settings where many other terrestrial climate proxies are fragmentary. The Eastern Mediterranean is one such region. Here we present an 80-kyr-long precisely-dated (by U-series) and high-resolution oxygen (δ(18)O) and carbon (δ(13)C) records from Dim Cave (~36°N) in SW Turkey. The glacial-interglacial δ(18)O variations in the Dim Cave speleothem are best explained in terms of changes in the trajectories of winter westerly air masses. These are along a northerly (European) track (isotopically less depleted) during the early last glaciation but are gradually depressed southward closer to the modern westerly track along the North African coast (more depleted) after c.50 kyr and remain in the southern track through the Last Glacial Maximum. The southward displacement of the westerly track reflects growth of the Fennoscandian ice sheet and its impact on westerly wind fields. Changes in δ(13)C are interpreted as reflecting soil organic matter composition and/or thickness. δ(13)C values are significantly more negative in interglacials reflecting active carbonic acid production in the soil and less negative in glacial times reflecting carbonate rock values. Several Heinrich events are recorded in the Dim record indicating intensification of westerly flow across this part of the EM. PMID:26337921

  3. VISUALIZATION OF MOLECULAR INTERACTIONS BY FLUORESCENCE COMPLEMENTATION

    PubMed Central

    Kerppola, Tom K.

    2008-01-01

    The visualization of protein complexes in living cells enables validation of protein interactions in their normal environment and determination of their subcellular localization. The bimolecular fluorescence complementation (BiFC) assay has been used to visualize interactions among multiple proteins in many cell types and organisms. This assay is based on the association between two fluorescent-protein fragments when they are brought together by an interaction between proteins fused to the fragments. Modified forms of this assay have been used to visualize the competition between alternative interaction partners and the covalent modification of proteins by ubiquitin family peptides. PMID:16625152

  4. Technologies for Networked Enabled Operations

    NASA Technical Reports Server (NTRS)

    Glass, B.; Levine, J.

    2005-01-01

    Current point-to-point data links will not scale to support future integration of surveillance, security, and globally-distributed air traffic data, and already hinders efficiency and capacity. While the FAA and industry focus on a transition to initial system-wide information management (SWIM) capabilities, this paper describes a set of initial studies of NAS network-enabled operations technology gaps targeted for maturity in later SWIM spirals (201 5-2020 timeframe).

  5. Echo-Enabled Harmonic Generation

    SciTech Connect

    Stupakov, Gennady; /SLAC

    2012-06-28

    A recently proposed concept of the Echo-Enabled Harmonic Generation (EEHG) FEL uses two laser modulators in combination with two dispersion sections to generate a high-harmonic density modulation in a relativistic beam. This seeding technique holds promise of a one-stage soft x-ray FEL that radiates not only transversely but also longitudinally coherent pulses. Currently, an experimental verification of the concept is being conducted at the SLAC National Accelerator Laboratory aimed at the demonstration of the EEHG.

  6. Echo-Enabled Harmonic Generation

    SciTech Connect

    Stupakov, Gennady

    2010-08-25

    A recently proposed concept of the Echo-Enabled Harmonic Generation (EEHG) FEL uses two laser modulators in combination with two dispersion sections to generate a high-harmonic density modulation in a relativistic beam. This seeding technique holds promise of a one-stage soft x-ray FEL that radiates not only transversely but also longitudinally coherent pulses. Currently, an experimental verification of the concept is being conducted at the SLAC National Accelerator Laboratory aimed at the demonstration of the EEHG.

  7. MEMS: Enabled Drug Delivery Systems.

    PubMed

    Cobo, Angelica; Sheybani, Roya; Meng, Ellis

    2015-05-01

    Drug delivery systems play a crucial role in the treatment and management of medical conditions. Microelectromechanical systems (MEMS) technologies have allowed the development of advanced miniaturized devices for medical and biological applications. This Review presents the use of MEMS technologies to produce drug delivery devices detailing the delivery mechanisms, device formats employed, and various biomedical applications. The integration of dosing control systems, examples of commercially available microtechnology-enabled drug delivery devices, remaining challenges, and future outlook are also discussed.

  8. New Generation Sensor Web Enablement

    PubMed Central

    Bröring, Arne; Echterhoff, Johannes; Jirka, Simon; Simonis, Ingo; Everding, Thomas; Stasch, Christoph; Liang, Steve; Lemmens, Rob

    2011-01-01

    Many sensor networks have been deployed to monitor Earth’s environment, and more will follow in the future. Environmental sensors have improved continuously by becoming smaller, cheaper, and more intelligent. Due to the large number of sensor manufacturers and differing accompanying protocols, integrating diverse sensors into observation systems is not straightforward. A coherent infrastructure is needed to treat sensors in an interoperable, platform-independent and uniform way. The concept of the Sensor Web reflects such a kind of infrastructure for sharing, finding, and accessing sensors and their data across different applications. It hides the heterogeneous sensor hardware and communication protocols from the applications built on top of it. The Sensor Web Enablement initiative of the Open Geospatial Consortium standardizes web service interfaces and data encodings which can be used as building blocks for a Sensor Web. This article illustrates and analyzes the recent developments of the new generation of the Sensor Web Enablement specification framework. Further, we relate the Sensor Web to other emerging concepts such as the Web of Things and point out challenges and resulting future work topics for research on Sensor Web Enablement. PMID:22163760

  9. Trace fluorescent labeling for protein crystallization

    PubMed Central

    Pusey, Marc; Barcena, Jorge; Morris, Michelle; Singhal, Anuj; Yuan, Qunying; Ng, Joseph

    2015-01-01

    Fluorescence can be a powerful tool to aid in the crystallization of proteins. In the trace-labeling approach, the protein is covalently derivatized with a high-quantum-yield visible-wavelength fluorescent probe. The final probe concentration typically labels ≤0.20% of the protein molecules, which has been shown to not affect the crystal nucleation or diffraction quality. The labeled protein is then used in a plate-screening experiment in the usual manner. As the most densely packed state of the protein is the crystalline form, then crystals show as the brightest objects in the well under fluorescent illumination. A study has been carried out on the effects of trace fluorescent labeling on the screening results obtained compared with nonlabeled protein, and it was found that considering the stochastic nature of the crystal nucleation process the presence of the probe did not affect the outcomes obtained. Other effects are realised when using fluorescence. Crystals are clearly seen even when buried in precipitate. This approach also finds ‘hidden’ leads, in the form of bright spots, with ∼30% of the leads found being optimized to crystals in a single-pass optimization trial. The use of visible fluorescence also enables the selection of colors that bypass interfering substances, and the screening materials do not have to be UV-transparent. PMID:26144224

  10. Parallel and convergent evolution of the dim-light vision gene RH1 in bats (Order: Chiroptera).

    PubMed

    Shen, Yong-Yi; Liu, Jie; Irwin, David M; Zhang, Ya-Ping

    2010-01-21

    Rhodopsin, encoded by the gene Rhodopsin (RH1), is extremely sensitive to light, and is responsible for dim-light vision. Bats are nocturnal mammals that inhabit poor light environments. Megabats (Old-World fruit bats) generally have well-developed eyes, while microbats (insectivorous bats) have developed echolocation and in general their eyes were degraded, however, dramatic differences in the eyes, and their reliance on vision, exist in this group. In this study, we examined the rod opsin gene (RH1), and compared its evolution to that of two cone opsin genes (SWS1 and M/LWS). While phylogenetic reconstruction with the cone opsin genes SWS1 and M/LWS generated a species tree in accord with expectations, the RH1 gene tree united Pteropodidae (Old-World fruit bats) and Yangochiroptera, with very high bootstrap values, suggesting the possibility of convergent evolution. The hypothesis of convergent evolution was further supported when nonsynonymous sites or amino acid sequences were used to construct phylogenies. Reconstructed RH1 sequences at internal nodes of the bat species phylogeny showed that: (1) Old-World fruit bats share an amino acid change (S270G) with the tomb bat; (2) Miniopterus share two amino acid changes (V104I, M183L) with Rhinolophoidea; (3) the amino acid replacement I123V occurred independently on four branches, and the replacements L99M, L266V and I286V occurred each on two branches. The multiple parallel amino acid replacements that occurred in the evolution of bat RH1 suggest the possibility of multiple convergences of their ecological specialization (i.e., various photic environments) during adaptation for the nocturnal lifestyle, and suggest that further attention is needed on the study of the ecology and behavior of bats.

  11. Inferred L/M cone opsin polymorphism of ancestral tarsiers sheds dim light on the origin of anthropoid primates.

    PubMed

    Melin, Amanda D; Matsushita, Yuka; Moritz, Gillian L; Dominy, Nathaniel J; Kawamura, Shoji

    2013-05-22

    Tarsiers are small nocturnal primates with a long history of fuelling debate on the origin and evolution of anthropoid primates. Recently, the discovery of M and L opsin genes in two sister species, Tarsius bancanus (Bornean tarsier) and Tarsius syrichta (Philippine tarsier), respectively, was interpreted as evidence of an ancestral long-to-middle (L/M) opsin polymorphism, which, in turn, suggested a diurnal or cathemeral (arrhythmic) activity pattern. This view is compatible with the hypothesis that stem tarsiers were diurnal; however, a reversion to nocturnality during the Middle Eocene, as evidenced by hyper-enlarged orbits, predates the divergence of T. bancanus and T. syrichta in the Late Miocene. Taken together, these findings suggest that some nocturnal tarsiers possessed high-acuity trichromatic vision, a concept that challenges prevailing views on the adaptive origins of the anthropoid visual system. It is, therefore, important to explore the plausibility and antiquity of trichromatic vision in the genus Tarsius. Here, we show that Sulawesi tarsiers (Tarsius tarsier), a phylogenetic out-group of Philippine and Bornean tarsiers, have an L opsin gene that is more similar to the L opsin gene of T. syrichta than to the M opsin gene of T. bancanus in non-synonymous nucleotide sequence. This result suggests that an L/M opsin polymorphism is the ancestral character state of crown tarsiers and raises the possibility that many hallmarks of the anthropoid visual system evolved under dim (mesopic) light conditions. This interpretation challenges the persistent nocturnal-diurnal dichotomy that has long informed debate on the origin of anthropoid primates. PMID:23536597

  12. Inferred L/M cone opsin polymorphism of ancestral tarsiers sheds dim light on the origin of anthropoid primates

    PubMed Central

    Melin, Amanda D.; Matsushita, Yuka; Moritz, Gillian L.; Dominy, Nathaniel J.; Kawamura, Shoji

    2013-01-01

    Tarsiers are small nocturnal primates with a long history of fuelling debate on the origin and evolution of anthropoid primates. Recently, the discovery of M and L opsin genes in two sister species, Tarsius bancanus (Bornean tarsier) and Tarsius syrichta (Philippine tarsier), respectively, was interpreted as evidence of an ancestral long-to-middle (L/M) opsin polymorphism, which, in turn, suggested a diurnal or cathemeral (arrhythmic) activity pattern. This view is compatible with the hypothesis that stem tarsiers were diurnal; however, a reversion to nocturnality during the Middle Eocene, as evidenced by hyper-enlarged orbits, predates the divergence of T. bancanus and T. syrichta in the Late Miocene. Taken together, these findings suggest that some nocturnal tarsiers possessed high-acuity trichromatic vision, a concept that challenges prevailing views on the adaptive origins of the anthropoid visual system. It is, therefore, important to explore the plausibility and antiquity of trichromatic vision in the genus Tarsius. Here, we show that Sulawesi tarsiers (Tarsius tarsier), a phylogenetic out-group of Philippine and Bornean tarsiers, have an L opsin gene that is more similar to the L opsin gene of T. syrichta than to the M opsin gene of T. bancanus in non-synonymous nucleotide sequence. This result suggests that an L/M opsin polymorphism is the ancestral character state of crown tarsiers and raises the possibility that many hallmarks of the anthropoid visual system evolved under dim (mesopic) light conditions. This interpretation challenges the persistent nocturnal–diurnal dichotomy that has long informed debate on the origin of anthropoid primates. PMID:23536597

  13. Dim-Light Sensitivity of Cells in the Awake Cat's Lateral Geniculate and Medial Interlaminar Nuclei: A Correlation With Behavior

    PubMed Central

    Kang, Incheol; Malpeli, Joseph G.

    2009-01-01

    Contrast thresholds of cells in the dorsal lateral geniculate (LGNd) and medial interlaminar (MIN) nuclei of awake cats were measured for scotopic and mesopic vision with drifting sine gratings (1/8, 2, and 4 cycles/deg [cpd]; 4-Hz temporal frequency). Thresholds for mean firing rate (F0) and temporally modulated responses (F1) were derived with receiver-operating-characteristic analyses and compared with behavioral measures recently reported by Kang and colleagues. Behavioral sensitivity was predicted by the neural responses of the most sensitive combinations of cell class and response mode: Y-cell F1 responses for 1/8 cpd, X-cell F1 responses for 2 cpd, and Y-cell F0 responses for 4 cpd. All previous estimates of neural scotopic increment thresholds in animal models fell between Weber's law (proportional to retinal illuminance) and the deVries–Rose law (proportional to the square root of illuminance). However, psychophysical experiments suggest that under appropriate conditions human scotopic vision follows the deVries–Rose law. If behavioral sensitivity is assumed to be determined by the most sensitive class of cells, this discrepancy is resolved. Under scotopic conditions, off-center Y cells were the most sensitive and these followed the deVries–Rose law fairly closely. MIN Y cells were, on average, 0.25 log units more sensitive than LGNd Y cells under scotopic conditions, supporting a previous proposal that the MIN is a specialization of the carnivore for dim-light vision. We conclude that both physiologically and behaviorally, cat and human scotopic vision are fundamentally similar, including adherence to the deVries–Rose law for detection of Gabor functions. PMID:19458145

  14. Tunable solid-state fluorescent materials for supramolecular encryption

    PubMed Central

    Hou, Xisen; Ke, Chenfeng; Bruns, Carson J.; McGonigal, Paul R.; Pettman, Roger B.; Stoddart, J. Fraser

    2015-01-01

    Tunable solid-state fluorescent materials are ideal for applications in security printing technologies. A document possesses a high level of security if its encrypted information can be authenticated without being decoded, while also being resistant to counterfeiting. Herein, we describe a heterorotaxane with tunable solid-state fluorescent emissions enabled through reversible manipulation of its aggregation by supramolecular encapsulation. The dynamic nature of this fluorescent material is based on a complex set of equilibria, whose fluorescence output depends non-linearly on the chemical inputs and the composition of the paper. By applying this system in fluorescent security inks, the information encoded in polychromic images can be protected in such a way that it is close to impossible to reverse engineer, as well as being easy to verify. This system constitutes a unique application of responsive complex equilibria in the form of a cryptographic algorithm that protects valuable information printed using tunable solid-state fluorescent materials. PMID:25901677

  15. Fluorescence Live Cell Imaging

    PubMed Central

    Ettinger, Andreas

    2014-01-01

    Fluorescence microscopy of live cells has become an integral part of modern cell biology. Fluorescent protein tags, live cell dyes, and other methods to fluorescently label proteins of interest provide a range of tools to investigate virtually any cellular process under the microscope. The two main experimental challenges in collecting meaningful live cell microscopy data are to minimize photodamage while retaining a useful signal-to-noise ratio, and to provide a suitable environment for cells or tissues to replicate physiological cell dynamics. This chapter aims to give a general overview on microscope design choices critical for fluorescence live cell imaging that apply to most fluorescence microscopy modalities, and on environmental control with a focus on mammalian tissue culture cells. In addition, we provide guidance on how to design and evaluate fluorescent protein constructs by spinning disk confocal microscopy. PMID:24974023

  16. Fluorescent fiber diagnostics

    DOEpatents

    Toeppen, John S.

    1994-10-04

    A fluorescent fiber (13) having a doped core (16) is pumped (11) by light (18) of a relatively short wavelength to produce fluorescence at a longer wavelength that is detected by detector (24). The level of fluorescence is monitored (26) and evaluated to provide information as to the excitation of the fiber (13) or the environment thereof. In particular, the level of intensity of the detected fluorescence may be used to measure the intensity of a light beam (18) passing axially through an optical fiber system (12) (FIG. 1 ), or the intensity of a light beam (46) passing radially through a fluorescent fiber (13) (FIG. 2 ), or the level of a fluid (32) in a tank (31) (FIG. 3 ), or a scintillation event (37) in a fluorescent fiber (13) pumped to produce amplification of the scintillation event (FIG. 4 ).

  17. Fluorescent fiber diagnostics

    DOEpatents

    Toeppen, John S.

    1994-01-01

    A fluorescent fiber (13) having a doped core (16) is pumped (11) by light (18) of a relatively short wavelength to produce fluorescence at a longer wavelength that is detected by detector (24). The level of fluorescence is monitored (26) and evaluated to provide information as to the excitation of the fiber (13) or the environment thereof. In particular, the level of intensity of the detected fluorescence may be used to measure the intensity of a light beam (18) passing axially through an optical fiber system (12) (FIG. 1 ), or the intensity of a light beam (46) passing radially through a fluorescent fiber (13) (FIG. 2 ), or the level of a fluid (32) in a tank (31) (FIG. 3 ), or a scintillation event (37) in a fluorescent fiber (13) pumped to produce amplification of the scintillation event (FIG. 4 ).

  18. Optimized microsystems-enabled photovoltaics

    DOEpatents

    Cruz-Campa, Jose Luis; Nielson, Gregory N.; Young, Ralph W.; Resnick, Paul J.; Okandan, Murat; Gupta, Vipin P.

    2015-09-22

    Technologies pertaining to designing microsystems-enabled photovoltaic (MEPV) cells are described herein. A first restriction for a first parameter of an MEPV cell is received. Subsequently, a selection of a second parameter of the MEPV cell is received. Values for a plurality of parameters of the MEPV cell are computed such that the MEPV cell is optimized with respect to the second parameter, wherein the values for the plurality of parameters are computed based at least in part upon the restriction for the first parameter.

  19. Increased sensitivity of bacterial detection in cerebrospinal fluid by fluorescent staining on low-fluorescence membrane filters.

    PubMed

    Durtschi, Jacob D; Erali, Maria; Bromley, L Kathryn; Herrmann, Mark G; Petti, Cathy A; Smith, Roger E; Voelkerding, Karl V

    2005-09-01

    A membrane-filter-based, fluorescent Gram stain method for bacterial detection in cerebrospinal fluid samples was developed and evaluated as a rapid, sensitive alternative to standard Gram stain protocols. A recently developed, modified version of the aluminium oxide membrane Anopore with low-fluorescence optical properties showed superior performance in this application. Other aspects of the fluorescent Gram stain system that were evaluated include membrane filter selection, strategies to reduce fluorescence fading and the effect of patient blood cells on bacterial detection in the fluorescently stained cerebrospinal fluid samples. The combination of the membrane filter's bacteria-concentrating ability and absolute retention along with high-contrast, fluorescent Gram discriminating dyes enabled rapid bacterial detection and Gram discrimination, with a 1-1.5 order of magnitude increase in the bacterial concentration limit of detection.

  20. Fluorescent minerals, a review

    USGS Publications Warehouse

    Modreski, P.J.; Aumente-Modreski, R.

    1996-01-01

    Fluorescent minerals are more than just an attractive novelty, and collecting them is a speciality for thousands of individuals who appreciate their beauty, rarity, and scientific value. Fluorescent properties can be used as an aid to mineral identification, locality determination, and distinction between natural and synthetic gemstones. This article gives an overview of those aspects of fluorescence that are of most interest to collectors, hobbyists, and mineralogists. -from Authors

  1. Trace fluorescent labeling for protein crystallization

    SciTech Connect

    Pusey, Marc Barcena, Jorge; Morris, Michelle; Singhal, Anuj; Yuan, Qunying; Ng, Joseph

    2015-06-27

    The presence of a covalently bound fluorescent probe at a concentration of <0.5% does not affect the outcome of macromolecule crystallization screening experiments. Additionally, the fluorescence can be used to determine new, not immediately apparent, lead crystallization conditions. Fluorescence can be a powerful tool to aid in the crystallization of proteins. In the trace-labeling approach, the protein is covalently derivatized with a high-quantum-yield visible-wavelength fluorescent probe. The final probe concentration typically labels ≤0.20% of the protein molecules, which has been shown to not affect the crystal nucleation or diffraction quality. The labeled protein is then used in a plate-screening experiment in the usual manner. As the most densely packed state of the protein is the crystalline form, then crystals show as the brightest objects in the well under fluorescent illumination. A study has been carried out on the effects of trace fluorescent labeling on the screening results obtained compared with nonlabeled protein, and it was found that considering the stochastic nature of the crystal nucleation process the presence of the probe did not affect the outcomes obtained. Other effects are realised when using fluorescence. Crystals are clearly seen even when buried in precipitate. This approach also finds ‘hidden’ leads, in the form of bright spots, with ∼30% of the leads found being optimized to crystals in a single-pass optimization trial. The use of visible fluorescence also enables the selection of colors that bypass interfering substances, and the screening materials do not have to be UV-transparent.

  2. Fluorescent reporter methods.

    PubMed

    Hutter, Harald

    2006-01-01

    The identification and cloning of the green fluorescent protein (GFP) from jellyfish marks the beginning of a new era of fluorescent reporters. In Caenorhabditis elegans, genetically encoded markers like the fluorescent proteins of the GFP family became the reporter of choice for gene expression studies and protein localization. The small size and transparency of the worm allows the visualization of in vivo dynamics, which increases the number of potential applications for fluorescent reporters tremendously. In combination with subcellular tags, GFP can be used to label subcellular structures like synapses allowing novel approaches to study developmental processes like synapse formation. Other fluorescent labels like small organic dyes, which are in widespread use in cell culture systems, are rarely used in C. elegans owing to difficulties in applying these labels through the impenetrable cuticle or eggshell of the animal. A notable exception is the use of lipophilic dyes, which are taken up by certain sensory neurons in the intact animal and can be introduced into the embryo after puncturing of the egg shell. This chapter covers the use of fluorescent dyes and fluorescent proteins in C. elegans. Emphasis is placed on microscopic techniques including wide field and confocal microscopy as well as time-lapse recordings. The use of fluorescent proteins as transgenic markers and image processing of fluorescence images are briefly discussed.

  3. Monte Carlo fluorescence microtomography

    NASA Astrophysics Data System (ADS)

    Cong, Alexander X.; Hofmann, Matthias C.; Cong, Wenxiang; Xu, Yong; Wang, Ge

    2011-07-01

    Fluorescence microscopy allows real-time monitoring of optical molecular probes for disease characterization, drug development, and tissue regeneration. However, when a biological sample is thicker than 1 mm, intense scattering of light would significantly degrade the spatial resolution of fluorescence microscopy. In this paper, we develop a fluorescence microtomography technique that utilizes the Monte Carlo method to image fluorescence reporters in thick biological samples. This approach is based on an l0-regularized tomography model and provides an excellent solution. Our studies on biomimetic tissue scaffolds have demonstrated that the proposed approach is capable of localizing and quantifying the distribution of optical molecular probe accurately and reliably.

  4. A Fluorescent Chromatophore Changes the Level of Fluorescence in a Reef Fish

    PubMed Central

    Wucherer, Matthias F.; Michiels, Nico K.

    2012-01-01

    Body coloration plays a major role in fish ecology and is predominantly generated using two principles: a) absorbance combined with reflection of the incoming light in pigment colors and b) scatter, refraction, diffraction and interference in structural colors. Poikilotherms, and especially fishes possess several cell types, so-called chromatophores, which employ either of these principles. Together, they generate the dynamic, multi-color patterns used in communication and camouflage. Several chromatophore types possess motile organelles, which enable rapid changes in coloration. Recently, we described red fluorescence in a number of marine fish and argued that it may be used for private communication in an environment devoid of red. Here, we describe the discovery of a chromatophore in fishes that regulates the distribution of fluorescent pigments in parts of the skin. These cells have a dendritic shape and contain motile fluorescent particles. We show experimentally that the fluorescent particles can be aggregated or dispersed through hormonal and nervous control. This is the first description of a stable and natural cytoskeleton-related fluorescence control mechanism in vertebrate cells. Its nervous control supports suggestions that fluorescence could act as a context-dependent signal in some marine fish species and encourages further research in this field. The fluorescent substance is stable under different chemical conditions and shows no discernible bleaching under strong, constant illumination. PMID:22701587

  5. Nanomaterial-Enabled Neural Stimulation.

    PubMed

    Wang, Yongchen; Guo, Liang

    2016-01-01

    Neural stimulation is a critical technique in treating neurological diseases and investigating brain functions. Traditional electrical stimulation uses electrodes to directly create intervening electric fields in the immediate vicinity of neural tissues. Second-generation stimulation techniques directly use light, magnetic fields or ultrasound in a non-contact manner. An emerging generation of non- or minimally invasive neural stimulation techniques is enabled by nanotechnology to achieve a high spatial resolution and cell-type specificity. In these techniques, a nanomaterial converts a remotely transmitted primary stimulus such as a light, magnetic or ultrasonic signal to a localized secondary stimulus such as an electric field or heat to stimulate neurons. The ease of surface modification and bio-conjugation of nanomaterials facilitates cell-type-specific targeting, designated placement and highly localized membrane activation. This review focuses on nanomaterial-enabled neural stimulation techniques primarily involving opto-electric, opto-thermal, magneto-electric, magneto-thermal and acousto-electric transduction mechanisms. Stimulation techniques based on other possible transduction schemes and general consideration for these emerging neurotechnologies are also discussed.

  6. Enabling Exploration Through Docking Standards

    NASA Technical Reports Server (NTRS)

    Hatfield, Caris A.

    2012-01-01

    Human exploration missions beyond low earth orbit will likely require international cooperation in order to leverage limited resources. International standards can help enable cooperative missions by providing well understood, predefined interfaces allowing compatibility between unique spacecraft and systems. The International Space Station (ISS) partnership has developed a publicly available International Docking System Standard (IDSS) that provides a solution to one of these key interfaces by defining a common docking interface. The docking interface provides a way for even dissimilar spacecraft to dock for exchange of crew and cargo, as well as enabling the assembly of large space systems. This paper provides an overview of the key attributes of the IDSS, an overview of the NASA Docking System (NDS), and the plans for updating the ISS with IDSS compatible interfaces. The NDS provides a state of the art, low impact docking system that will initially be made available to commercial crew and cargo providers. The ISS will be used to demonstrate the operational utility of the IDSS interface as a foundational technology for cooperative exploration.

  7. Nanomaterial-Enabled Neural Stimulation

    PubMed Central

    Wang, Yongchen; Guo, Liang

    2016-01-01

    Neural stimulation is a critical technique in treating neurological diseases and investigating brain functions. Traditional electrical stimulation uses electrodes to directly create intervening electric fields in the immediate vicinity of neural tissues. Second-generation stimulation techniques directly use light, magnetic fields or ultrasound in a non-contact manner. An emerging generation of non- or minimally invasive neural stimulation techniques is enabled by nanotechnology to achieve a high spatial resolution and cell-type specificity. In these techniques, a nanomaterial converts a remotely transmitted primary stimulus such as a light, magnetic or ultrasonic signal to a localized secondary stimulus such as an electric field or heat to stimulate neurons. The ease of surface modification and bio-conjugation of nanomaterials facilitates cell-type-specific targeting, designated placement and highly localized membrane activation. This review focuses on nanomaterial-enabled neural stimulation techniques primarily involving opto-electric, opto-thermal, magneto-electric, magneto-thermal and acousto-electric transduction mechanisms. Stimulation techniques based on other possible transduction schemes and general consideration for these emerging neurotechnologies are also discussed. PMID:27013938

  8. Maximizing the biochemical resolving power of fluorescence microscopy.

    PubMed

    Esposito, Alessandro; Popleteeva, Marina; Venkitaraman, Ashok R

    2013-01-01

    Most recent advances in fluorescence microscopy have focused on achieving spatial resolutions below the diffraction limit. However, the inherent capability of fluorescence microscopy to non-invasively resolve different biochemical or physical environments in biological samples has not yet been formally described, because an adequate and general theoretical framework is lacking. Here, we develop a mathematical characterization of the biochemical resolution in fluorescence detection with Fisher information analysis. To improve the precision and the resolution of quantitative imaging methods, we demonstrate strategies for the optimization of fluorescence lifetime, fluorescence anisotropy and hyperspectral detection, as well as different multi-dimensional techniques. We describe optimized imaging protocols, provide optimization algorithms and describe precision and resolving power in biochemical imaging thanks to the analysis of the general properties of Fisher information in fluorescence detection. These strategies enable the optimal use of the information content available within the limited photon-budget typically available in fluorescence microscopy. This theoretical foundation leads to a generalized strategy for the optimization of multi-dimensional optical detection, and demonstrates how the parallel detection of all properties of fluorescence can maximize the biochemical resolving power of fluorescence microscopy, an approach we term Hyper Dimensional Imaging Microscopy (HDIM). Our work provides a theoretical framework for the description of the biochemical resolution in fluorescence microscopy, irrespective of spatial resolution, and for the development of a new class of microscopes that exploit multi-parametric detection systems. PMID:24204821

  9. Maximizing the Biochemical Resolving Power of Fluorescence Microscopy

    PubMed Central

    Esposito, Alessandro; Popleteeva, Marina; Venkitaraman, Ashok R.

    2013-01-01

    Most recent advances in fluorescence microscopy have focused on achieving spatial resolutions below the diffraction limit. However, the inherent capability of fluorescence microscopy to non-invasively resolve different biochemical or physical environments in biological samples has not yet been formally described, because an adequate and general theoretical framework is lacking. Here, we develop a mathematical characterization of the biochemical resolution in fluorescence detection with Fisher information analysis. To improve the precision and the resolution of quantitative imaging methods, we demonstrate strategies for the optimization of fluorescence lifetime, fluorescence anisotropy and hyperspectral detection, as well as different multi-dimensional techniques. We describe optimized imaging protocols, provide optimization algorithms and describe precision and resolving power in biochemical imaging thanks to the analysis of the general properties of Fisher information in fluorescence detection. These strategies enable the optimal use of the information content available within the limited photon-budget typically available in fluorescence microscopy. This theoretical foundation leads to a generalized strategy for the optimization of multi-dimensional optical detection, and demonstrates how the parallel detection of all properties of fluorescence can maximize the biochemical resolving power of fluorescence microscopy, an approach we term Hyper Dimensional Imaging Microscopy (HDIM). Our work provides a theoretical framework for the description of the biochemical resolution in fluorescence microscopy, irrespective of spatial resolution, and for the development of a new class of microscopes that exploit multi-parametric detection systems. PMID:24204821

  10. Diversity and evolution of coral fluorescent proteins.

    PubMed

    Alieva, Naila O; Konzen, Karen A; Field, Steven F; Meleshkevitch, Ella A; Hunt, Marguerite E; Beltran-Ramirez, Victor; Miller, David J; Wiedenmann, Jörg; Salih, Anya; Matz, Mikhail V

    2008-07-16

    GFP-like fluorescent proteins (FPs) are the key color determinants in reef-building corals (class Anthozoa, order Scleractinia) and are of considerable interest as potential genetically encoded fluorescent labels. Here we report 40 additional members of the GFP family from corals. There are three major paralogous lineages of coral FPs. One of them is retained in all sampled coral families and is responsible for the non-fluorescent purple-blue color, while each of the other two evolved a full complement of typical coral fluorescent colors (cyan, green, and red) and underwent sorting between coral groups. Among the newly cloned proteins are a "chromo-red" color type from Echinopora forskaliana (family Faviidae) and pink chromoprotein from Stylophora pistillata (Pocilloporidae), both evolving independently from the rest of coral chromoproteins. There are several cyan FPs that possess a novel kind of excitation spectrum indicating a neutral chromophore ground state, for which the residue E167 is responsible (numeration according to GFP from A. victoria). The chromoprotein from Acropora millepora is an unusual blue instead of purple, which is due to two mutations: S64C and S183T. We applied a novel probabilistic sampling approach to recreate the common ancestor of all coral FPs as well as the more derived common ancestor of three main fluorescent colors of the Faviina suborder. Both proteins were green such as found elsewhere outside class Anthozoa. Interestingly, a substantial fraction of the all-coral ancestral protein had a chromohore apparently locked in a non-fluorescent neutral state, which may reflect the transitional stage that enabled rapid color diversification early in the history of coral FPs. Our results highlight the extent of convergent or parallel evolution of the color diversity in corals, provide the foundation for experimental studies of evolutionary processes that led to color diversification, and enable a comparative analysis of structural

  11. Diversity and Evolution of Coral Fluorescent Proteins

    PubMed Central

    Alieva, Naila O.; Konzen, Karen A.; Field, Steven F.; Meleshkevitch, Ella A.; Hunt, Marguerite E.; Beltran-Ramirez, Victor; Miller, David J.; Wiedenmann, Jörg; Salih, Anya; Matz, Mikhail V.

    2008-01-01

    GFP-like fluorescent proteins (FPs) are the key color determinants in reef-building corals (class Anthozoa, order Scleractinia) and are of considerable interest as potential genetically encoded fluorescent labels. Here we report 40 additional members of the GFP family from corals. There are three major paralogous lineages of coral FPs. One of them is retained in all sampled coral families and is responsible for the non-fluorescent purple-blue color, while each of the other two evolved a full complement of typical coral fluorescent colors (cyan, green, and red) and underwent sorting between coral groups. Among the newly cloned proteins are a “chromo-red” color type from Echinopora forskaliana (family Faviidae) and pink chromoprotein from Stylophora pistillata (Pocilloporidae), both evolving independently from the rest of coral chromoproteins. There are several cyan FPs that possess a novel kind of excitation spectrum indicating a neutral chromophore ground state, for which the residue E167 is responsible (numeration according to GFP from A. victoria). The chromoprotein from Acropora millepora is an unusual blue instead of purple, which is due to two mutations: S64C and S183T. We applied a novel probabilistic sampling approach to recreate the common ancestor of all coral FPs as well as the more derived common ancestor of three main fluorescent colors of the Faviina suborder. Both proteins were green such as found elsewhere outside class Anthozoa. Interestingly, a substantial fraction of the all-coral ancestral protein had a chromohore apparently locked in a non-fluorescent neutral state, which may reflect the transitional stage that enabled rapid color diversification early in the history of coral FPs. Our results highlight the extent of convergent or parallel evolution of the color diversity in corals, provide the foundation for experimental studies of evolutionary processes that led to color diversification, and enable a comparative analysis of structural

  12. Cannula-based computational fluorescence microscopy

    NASA Astrophysics Data System (ADS)

    Kim, Ganghun; Nagarajan, Naveen; Capecchi, Mario R.; Menon, Rajesh

    2015-06-01

    We converted a solid-glass cannula into a high-resolution widefield fluorescence microscope. Calibrating the space-variant point-spread functions of the cannula and applying a nonlinear optimization algorithm to reconstruct object details enable this development. The resolution of our system is ˜1 μm, and fluorophore position is determined to a precision of ˜20 nm. Images of microglia from fixed slices of mouse brains at various post-natal development stages were also obtained.

  13. Reflectance and fluorescence hyperspectral elastic image registration

    NASA Astrophysics Data System (ADS)

    Lange, Holger; Baker, Ross; Hakansson, Johan; Gustafsson, Ulf P.

    2004-05-01

    Science and Technology International (STI) presents a novel multi-modal elastic image registration approach for a new hyperspectral medical imaging modality. STI's HyperSpectral Diagnostic Imaging (HSDI) cervical instrument is used for the early detection of uterine cervical cancer. A Computer-Aided-Diagnostic (CAD) system is being developed to aid the physician with the diagnosis of pre-cancerous and cancerous tissue regions. The CAD system uses the fusion of multiple data sources to optimize its performance. The key enabling technology for the data fusion is image registration. The difficulty lies in the image registration of fluorescence and reflectance hyperspectral data due to the occurrence of soft tissue movement and the limited resemblance of these types of imagery. The presented approach is based on embedding a reflectance image in the fluorescence hyperspectral imagery. Having a reflectance image in both data sets resolves the resemblance problem and thereby enables the use of elastic image registration algorithms required to compensate for soft tissue movements. Several methods of embedding the reflectance image in the fluorescence hyperspectral imagery are described. Initial experiments with human subject data are presented where a reflectance image is embedded in the fluorescence hyperspectral imagery.

  14. Primary Care's Dim Prognosis

    ERIC Educational Resources Information Center

    Alper, Philip R.

    2010-01-01

    Given the chorus of approval for primary care emanating from every party to the health reform debate, one might suppose that the future for primary physicians is bright. Yet this is far from certain. And when one looks to history and recognizes that primary care medicine has failed virtually every conceivable market test in recent years, its…

  15. Simulation enabled safeguards assessment methodology

    SciTech Connect

    Bean, Robert; Bjornard, Trond; Larson, Tom

    2007-07-01

    It is expected that nuclear energy will be a significant component of future supplies. New facilities, operating under a strengthened international nonproliferation regime will be needed. There is good reason to believe virtual engineering applied to the facility design, as well as to the safeguards system design will reduce total project cost and improve efficiency in the design cycle. Simulation Enabled Safeguards Assessment MEthodology has been developed as a software package to provide this capability for nuclear reprocessing facilities. The software architecture is specifically designed for distributed computing, collaborative design efforts, and modular construction to allow step improvements in functionality. Drag and drop wire-frame construction allows the user to select the desired components from a component warehouse, render the system for 3D visualization, and, linked to a set of physics libraries and/or computational codes, conduct process evaluations of the system they have designed. (authors)

  16. Simulation Enabled Safeguards Assessment Methodology

    SciTech Connect

    Robert Bean; Trond Bjornard; Thomas Larson

    2007-09-01

    It is expected that nuclear energy will be a significant component of future supplies. New facilities, operating under a strengthened international nonproliferation regime will be needed. There is good reason to believe virtual engineering applied to the facility design, as well as to the safeguards system design will reduce total project cost and improve efficiency in the design cycle. Simulation Enabled Safeguards Assessment MEthodology (SESAME) has been developed as a software package to provide this capability for nuclear reprocessing facilities. The software architecture is specifically designed for distributed computing, collaborative design efforts, and modular construction to allow step improvements in functionality. Drag and drop wireframe construction allows the user to select the desired components from a component warehouse, render the system for 3D visualization, and, linked to a set of physics libraries and/or computational codes, conduct process evaluations of the system they have designed.

  17. Context-Enabled Business Intelligence

    SciTech Connect

    Troy Hiltbrand

    2012-04-01

    To truly understand context and apply it in business intelligence, it is vital to understand what context is and how it can be applied in addressing organizational needs. Context describes the facets of the environment that impact the way that end users interact with the system. Context includes aspects of location, chronology, access method, demographics, social influence/ relationships, end-user attitude/ emotional state, behavior/ past behavior, and presence. To be successful in making Business Intelligence content enabled, it is important to be able to capture the context of use user. With advances in technology, there are a number of ways in which this user based information can be gathered and exposed to enhance the overall end user experience.

  18. Fluorescence in insects

    NASA Astrophysics Data System (ADS)

    Welch, Victoria L.; Van Hooijdonk, Eloise; Intrater, Nurit; Vigneron, Jean-Pol

    2012-10-01

    Fluorescent molecules are much in demand for biosensors, solar cells, LEDs and VCSEL diodes, therefore, considerable efforts have been expended in designing and tailoring fluorescence to specific technical applications. However, naturally occurring fluorescence of diverse types has been reported from a wide array of living organisms: most famously, the jellyfish Aequorea victoria, but also in over 100 species of coral and in the cuticle of scorpions, where it is the rule, rather than the exception. Despite the plethora of known insect species, comparatively few quantitative studies have been made of insect fluorescence. Because of the potential applications of natural fluorescence, studies in this field have relevance to both physics and biology. Therefore, in this paper, we review the literature on insect fluorescence, before documenting its occurrence in the longhorn beetles Sternotomis virescens, Sternotomis variabilis var. semi rufescens, Anoplophora elegans and Stellognatha maculata, the tiger beetles Cicindela maritima and Cicindela germanica and the weevil Pachyrrhynchus gemmatus purpureus. Optical features of insect fluorescence, including emitted wavelength, molecular ageing and naturally occurring combinations of fluorescence with bioluminescence and colour-producing structures are discussed.

  19. The Drosophila Transcription Factor Dimmed Affects Neuronal Growth and Differentiation in Multiple Ways Depending on Neuron Type and Developmental Stage

    PubMed Central

    Liu, Yiting; Luo, Jiangnan; Nässel, Dick R.

    2016-01-01

    Growth of postmitotic neurons occurs during different stages of development, including metamorphosis, and may also be part of neuronal plasticity and regeneration. Recently we showed that growth of post-mitotic neuroendocrine cells expressing the basic helix loop helix (bHLH) transcription factor Dimmed (Dimm) in Drosophila could be regulated by insulin/IGF signaling and the insulin receptor (dInR). Dimm is also known to confer a secretory phenotype to neuroendocrine cells and can be part of a combinatorial code specifying terminal differentiation in peptidergic neurons. To further understand the mechanisms of Dimm function we ectopically expressed Dimm or Dimm together with dInR in a wide range of Dimm positive and Dimm negative peptidergic neurons, sensory neurons, interneurons, motor neurons, and gut endocrine cells. We provide further evidence that dInR mediated cell growth occurs in a Dimm dependent manner and that one source of insulin-like peptide (DILP) for dInR mediated cell growth in the CNS is DILP6 from glial cells. Expressing both Dimm and dInR in Dimm negative neurons induced growth of cell bodies, whereas dInR alone did not. We also found that Dimm alone can regulate cell growth depending on specific cell type. This may be explained by the finding that the dInR is a direct target of Dimm. Conditional gene targeting experiments showed that Dimm alone could affect cell growth in certain neuron types during metamorphosis or in the adult stage. Another important finding was that ectopic Dimm inhibits apoptosis of several types of neurons normally destined for programmed cell death (PCD). Taken together our results suggest that Dimm plays multiple transcriptional roles at different developmental stages in a cell type-specific manner. In some cell types ectopic Dimm may act together with resident combinatorial code transcription factors and affect terminal differentiation, as well as act in transcriptional networks that participate in long term maintenance

  20. Engineering fluorescent proteins.

    PubMed

    Miyawaki, Atsushi; Nagai, Takeharu; Mizuno, Hideaki

    2005-01-01

    Green fluorescent protein from the jellyfish Aequorea victora (GFP) and GFP-like proteins from Anthozoa species encode light-absorbing chromophores intrinsically within their respective protein sequences. Recent studies have made progress in obtaining bright variants of these proteins which develop chromophores quickly and efficiently, as well as novel fluorescent proteins that photoactivate or photoconvert, i.e., become fluorescent or change colors upon illumination at specific wavelengths. Also, monomeric versions of these proteins have been engineered for fusion protein applications. Simple GFP variants and circularly permuted GFP variants have been used to develop fluorescent probes that sense physiological signals such as membrane potential and concentrations of free calcium. Further molecular characterization of the structure and maturation of these proteins is in progress, aimed at providing information for rational design of variants with desired fluorescence properties.

  1. Magnetic Flux of EUV Arcade and Dimming Regions as a Relevant Parameter for Early Diagnostics of Solar Eruptions - Sources of Non-recurrent Geomagnetic Storms and Forbush Decreases

    NASA Astrophysics Data System (ADS)

    Chertok, I. M.; Grechnev, V. V.; Belov, A. V.; Abunin, A. A.

    2013-01-01

    This study aims at the early diagnostics of the geoeffectiveness of coronal mass ejections (CMEs) from quantitative parameters of the accompanying EUV dimming and arcade events. We study events of the 23th solar cycle, in which major non-recurrent geomagnetic storms (GMS) with Dst<-100 nT are sufficiently reliably identified with their solar sources in the central part of the disk. Using the SOHO/EIT 195 Å images and MDI magnetograms, we select significant dimming and arcade areas and calculate summarized unsigned magnetic fluxes in these regions at the photospheric level. The high relevance of this eruption parameter is displayed by its pronounced correlation with the Forbush decrease (FD) magnitude, which, unlike GMSs, does not depend on the sign of the B z component but is determined by global characteristics of ICMEs. Correlations with the same magnetic flux in the solar source region are found for the GMS intensity (at the first step, without taking into account factors determining the B z component near the Earth), as well as for the temporal intervals between the solar eruptions and the GMS onset and peak times. The larger the magnetic flux, the stronger the FD and GMS intensities are and the shorter the ICME transit time is. The revealed correlations indicate that the main quantitative characteristics of major non-recurrent space weather disturbances are largely determined by measurable parameters of solar eruptions, in particular, by the magnetic flux in dimming areas and arcades, and can be tentatively estimated in advance with a lead time from 1 to 4 days. For GMS intensity, the revealed dependencies allow one to estimate a possible value, which can be expected if the B z component is negative.

  2. Preclinical fluorescent mouse models of pancreatic cancer

    NASA Astrophysics Data System (ADS)

    Bouvet, Michael; Hoffman, Robert M.

    2007-02-01

    Here we describe our cumulative experience with the development and preclinical application of several highly fluorescent, clinically-relevant, metastatic orthotopic mouse models of pancreatic cancer. These models utilize the human pancreatic cancer cell lines which have been genetically engineered to selectively express high levels of the bioluminescent green fluorescent (GFP) or red fluorescent protein (RFP). Fluorescent tumors are established subcutaneously in nude mice, and tumor fragments are then surgically transplanted onto the pancreas. Locoregional tumor growth and distant metastasis of these orthotopic implants occurs spontaneously and rapidly throughout the abdomen in a manner consistent with clinical human disease. Highly specific, high-resolution, real-time visualization of tumor growth and metastasis may be achieved in vivo without the need for contrast agents, invasive techniques, or expensive imaging equipment. We have shown a high correlation between florescent optical imaging and magnetic resonance imaging in these models. Alternatively, transplantation of RFP-expressing tumor fragments onto the pancreas of GFP-expressing transgenic mice may be used to facilitate visualization of tumor-host interaction between the pancreatic tumor fragments and host-derived stroma and vasculature. Such in vivo models have enabled us to serially visualize and acquire images of the progression of pancreatic cancer in the live animal, and to demonstrate the real-time antitumor and antimetastatic effects of several novel therapeutic strategies on pancreatic malignancy. These fluorescent models are therefore powerful and reliable tools with which to investigate human pancreatic cancer and therapeutic strategies directed against it.

  3. Bloch surface wave-enhanced fluorescence biosensor.

    PubMed

    Toma, Koji; Descrovi, Emiliano; Toma, Mana; Ballarini, Mirko; Mandracci, Pietro; Giorgis, Fabrizio; Mateescu, Anca; Jonas, Ulrich; Knoll, Wolfgang; Dostálek, Jakub

    2013-05-15

    A new approach to signal amplification in fluorescence-based assays for sensitive detection of molecular analytes is reported. It relies on a sensor chip carrying a one-dimensional photonic crystal (1DPC) composed of two piled up segments which are designed to increase simultaneously the excitation rate and the collection efficiency of fluorescence light. The top segment supports Bloch surface waves (BSWs) at the excitation wavelength and the bottom segment serves as a Bragg mirror for the emission wavelength of used fluorophore labels. The enhancement of the excitation rate on the sensor surface is achieved through the resonant coupling to BSWs that is associated with strong increase of the field intensity. The increasing of collection efficiency of fluorescence light emitted from the sensor surface is pursued by using the Bragg mirror that minimizes its leakage into a substrate and provides its beaming toward a detector. In order to exploit the whole evanescent field of BSW, extended three-dimensional hydrogel-based binding matrix that is functionalized with catcher molecules is attached to 1DPC for capturing of target analyte from a sample. Simulations supported by experiments are presented to illustrate the design and determined the performance characteristics of BSW-enhanced fluorescence spectroscopy. A model immunoassay experiment demonstrates that the reported approach enables increasing signal to noise ratio, resulting in about one order of magnitude improved limit of detection (LOD) with respect to regular total internal reflection fluorescence (TIRF) configuration. PMID:23291217

  4. Fluorescence properties of melanins from opioid peptides.

    PubMed

    Mosca, L; De Marco, C; Fontana, M; Rosei, M A

    1999-11-01

    Recently our group synthesized a new class of melanins obtained by the tyrosinase-catalyzed oxidation of opioid peptides (opiomelanins). Owing to the presence of the peptide moiety such pigments exhibit high solubility in hydrophilic solvents, which allows spectroscopic investigations. In particular, the absence of solid-state quenching effects enables the study of melanin fluorescence properties, till now poorly investigated due to the complete insolubility of melanins produced from tyrosine or Dopa. Opiomelanins dissolved in aqueous medium show a characteristic emission peaked at 440 and 520 nm when excited around 330 nm, where a maximum is observed in the absorption spectrum. Kinetic measurements performed on the tyrosinase-catalyzed oxidation of opioid peptides show that the 440-nm fluorescence band arises in the early stages of peptide oxidation, whereas the 520-nm band appears in later stages of oxidation, i.e., during the polymerization of indole-quinone units. Moreover, molecular sieve fractionation shows that in the opiomelanin fraction with a molecular weight lower than 10 kDa the 440-nm band is dominant in the fluorescence spectrum. The breakdown of the polymer induced by hydrogen peroxide and light (i.e., the photobleaching of melanin pigments) produces a marked enhancement of the 440-nm fluorescence band while the 520-nm band disappears. Hence, our findings suggest that the observed fluorescence contains contributions from both oligomeric units (440-nm band) and high-molecular-weight polymers (520-nm band). PMID:10525290

  5. Enabling Participation In Exoplanet Science

    NASA Astrophysics Data System (ADS)

    Taylor, Stuart F.

    2015-08-01

    Determining the distribution of exoplanets has required the contributions of a community of astronomers, who all require the support of colleagues to finish their projects in a manner to enable them to enter new collaborations to continue to contribute to understanding exoplanet science.The contributions of each member of the astronomy community are to be encouraged and must never be intentionally obstructed.We present a member’s long pursuit to be a contributing part of the exoplanet community through doing transit photometry as a means of commissioning the telescopes for a new observatory, followed by pursuit of interpreting the distributions in exoplanet parameter data.We present how the photometry projects have been presented as successful by the others who have claimed to have completed them, but how by requiring its employees to present results while omitting one member has been obstructive against members working together and has prevented the results from being published in what can genuinely be called a peer-reviewed fashion.We present how by tolerating one group to obstruct one member from finishing participation and then falsely denying credit is counterproductive to doing science.We show how expecting one member to attempt to go around an ostracizing group by starting something different is destructive to the entire profession. We repeat previously published appeals to help ostracized members to “go around the observatory” by calling for discussion on how the community must act to reverse cases of shunning, bullying, and other abuses. Without better recourse and support from the community, actions that do not meet standard good collegial behavior end up forcing good members from the community. The most important actions are to enable an ostracized member to have recourse to participating in group papers by either working through other authors or through the journal. All journals and authors must expect that no co-author is keeping out a major

  6. Enabling technology for human collaboration.

    SciTech Connect

    Murphy, Tim Andrew; Jones, Wendell Bruce; Warner, David Jay; Doser, Adele Beatrice; Johnson, Curtis Martin; Merkle, Peter Benedict

    2003-11-01

    This report summarizes the results of a five-month LDRD late start project which explored the potential of enabling technology to improve the performance of small groups. The purpose was to investigate and develop new methods to assist groups working in high consequence, high stress, ambiguous and time critical situations, especially those for which it is impractical to adequately train or prepare. A testbed was constructed for exploratory analysis of a small group engaged in tasks with high cognitive and communication performance requirements. The system consisted of five computer stations, four with special devices equipped to collect physiologic, somatic, audio and video data. Test subjects were recruited and engaged in a cooperative video game. Each team member was provided with a sensor array for physiologic and somatic data collection while playing the video game. We explored the potential for real-time signal analysis to provide information that enables emergent and desirable group behavior and improved task performance. The data collected in this study included audio, video, game scores, physiological, somatic, keystroke, and mouse movement data. The use of self-organizing maps (SOMs) was explored to search for emergent trends in the physiological data as it correlated with the video, audio and game scores. This exploration resulted in the development of two approaches for analysis, to be used concurrently, an individual SOM and a group SOM. The individual SOM was trained using the unique data of each person, and was used to monitor the effectiveness and stress level of each member of the group. The group SOM was trained using the data of the entire group, and was used to monitor the group effectiveness and dynamics. Results suggested that both types of SOMs were required to adequately track evolutions and shifts in group effectiveness. Four subjects were used in the data collection and development of these tools. This report documents a proof of concept

  7. Optically Modulated Fluorophores for Selective Fluorescence Signal Recovery

    PubMed Central

    Richards, Chris I.; Hsiang, Jung-Cheng; Senapati, Dulal; Patel, Sandeep; Yu, Junhua; Vosch, Tom; Dickson, Robert M.

    2009-01-01

    Fluorescence imaging in biological sciences is hindered by significant depth-dependent signal attenuation and high fluorescent backgrounds. We have developed optically modulated near-IR-emitting few-atom Ag nanodots that are selectively and dynamically photobrightened upon simultaneous excitation with a secondary laser enabling high sensitivity image extraction to reveal only the demodulated fluorophores. Image demodulation is demonstrated in high background environments to extract weak signals from completely obscuring background emission. PMID:19284790

  8. Good pharmacovigilance practices: technology enabled.

    PubMed

    Nelson, Robert C; Palsulich, Bruce; Gogolak, Victor

    2002-01-01

    The assessment of spontaneous reports is most effective it is conducted within a defined and rigorous process. The framework for good pharmacovigilance process (GPVP) is proposed as a subset of good postmarketing surveillance process (GPMSP), a functional structure for both a public health and corporate risk management strategy. GPVP has good practices that implement each step within a defined process. These practices are designed to efficiently and effectively detect and alert the drug safety professional to new and potentially important information on drug-associated adverse reactions. These practices are enabled by applied technology designed specifically for the review and assessment of spontaneous reports. Specific practices include rules-based triage, active query prompts for severe organ insults, contextual single case evaluation, statistical proportionality and correlational checks, case-series analyses, and templates for signal work-up and interpretation. These practices and the overall GPVP are supported by state-of-the-art web-based systems with powerful analytical engines, workflow and audit trials to allow validated systems support for valid drug safety signalling efforts. It is also important to understand that a process has a defined set of steps and any one cannot stand independently. Specifically, advanced use of technical alerting methods in isolation can mislead and allow one to misunderstand priorities and relative value. In the end, pharmacovigilance is a clinical art and a component process to the science of pharmacoepidemiology and risk management. PMID:12071777

  9. Biological applications of confocal fluorescence polarization microscopy

    NASA Astrophysics Data System (ADS)

    Bigelow, Chad E.

    Fluorescence polarization microscopy is a powerful modality capable of sensing changes in the physical properties and local environment of fluorophores. In this thesis we present new applications for the technique in cancer diagnosis and treatment and explore the limits of the modality in scattering media. We describe modifications to our custom-built confocal fluorescence microscope that enable dual-color imaging, optical fiber-based confocal spectroscopy and fluorescence polarization imaging. Experiments are presented that indicate the performance of the instrument for all three modalities. The limits of confocal fluorescence polarization imaging in scattering media are explored and the microscope parameters necessary for accurate polarization images in this regime are determined. A Monte Carlo routine is developed to model the effect of scattering on images. Included in it are routines to track the polarization state of light using the Mueller-Stokes formalism and a model for fluorescence generation that includes sampling the excitation light polarization ellipse, Brownian motion of excited-state fluorophores in solution, and dipole fluorophore emission. Results from this model are compared to experiments performed on a fluorophore-embedded polymer rod in a turbid medium consisting of polystyrene microspheres in aqueous suspension. We demonstrate the utility of the fluorescence polarization imaging technique for removal of contaminating autofluorescence and for imaging photodynamic therapy drugs in cell monolayers. Images of cells expressing green fluorescent protein are extracted from contaminating fluorescein emission. The distribution of meta-tetrahydroxypheny1chlorin in an EMT6 cell monolayer is also presented. A new technique for imaging enzyme activity is presented that is based on observing changes in the anisotropy of fluorescently-labeled substrates. Proof-of-principle studies are performed in a model system consisting of fluorescently labeled bovine

  10. A 3D printed fluidic device that enables integrated features.

    PubMed

    Anderson, Kari B; Lockwood, Sarah Y; Martin, R Scott; Spence, Dana M

    2013-06-18

    Fluidic devices fabricated using conventional soft lithography are well suited as prototyping methods. Three-dimensional (3D) printing, commonly used for producing design prototypes in industry, allows for one step production of devices. 3D printers build a device layer by layer based on 3D computer models. Here, a reusable, high throughput, 3D printed fluidic device was created that enables flow and incorporates a membrane above a channel in order to study drug transport and affect cells. The device contains 8 parallel channels, 3 mm wide by 1.5 mm deep, connected to a syringe pump through standard, threaded fittings. The device was also printed to allow integration with commercially available membrane inserts whose bottoms are constructed of a porous polycarbonate membrane; this insert enables molecular transport to occur from the channel to above the well. When concentrations of various antibiotics (levofloxacin and linezolid) are pumped through the channels, approximately 18-21% of the drug migrates through the porous membrane, providing evidence that this device will be useful for studies where drug effects on cells are investigated. Finally, we show that mammalian cells cultured on this membrane can be affected by reagents flowing through the channels. Specifically, saponin was used to compromise cell membranes, and a fluorescent label was used to monitor the extent, resulting in a 4-fold increase in fluorescence for saponin treated cells.

  11. Highly thermostable fluorescent proteins

    DOEpatents

    Bradbury, Andrew M.; Waldo, Geoffrey S.; Kiss, Csaba

    2011-03-22

    Thermostable fluorescent proteins (TSFPs), methods for generating these and other stability-enhanced proteins, polynucleotides encoding such proteins, and assays and method for using the TSFPs and TSFP-encoding nucleic acid molecules are provided. The TSFPs of the invention show extremely enhanced levels of stability and thermotolerance. In one case, for example, a TSFP of the invention is so stable it can be heated to 99.degree. C. for short periods of time without denaturing, and retains 85% of its fluorescence when heated to 80.degree. C. for several minutes. The invention also provides a method for generating stability-enhanced variants of a protein, including but not limited to fluorescent proteins.

  12. Highly thermostable fluorescent proteins

    DOEpatents

    Bradbury, Andrew M.; Waldo, Geoffrey S.; Kiss, Csaba

    2012-05-01

    Thermostable fluorescent proteins (TSFPs), methods for generating these and other stability-enhanced proteins, polynucleotides encoding such proteins, and assays and method for using the TSFPs and TSFP-encoding nucleic acid molecules are provided. The TSFPs of the invention show extremely enhanced levels of stability and thermotolerance. In one case, for example, a TSFP of the invention is so stable it can be heated to 99.degree. C. for short periods of time without denaturing, and retains 85% of its fluorescence when heated to 80.degree. C. for several minutes. The invention also provides a method for generating stability-enhanced variants of a protein, including but not limited to fluorescent proteins.

  13. Highly thermostable fluorescent proteins

    DOEpatents

    Bradbury, Andrew M.; Waldo, Geoffrey S.; Kiss, Csaba

    2011-11-29

    Thermostable fluorescent proteins (TSFPs), methods for generating these and other stability-enhanced proteins, polynucleotides encoding such proteins, and assays and method for using the TSFPs and TSFP-encoding nucleic acid molecules are provided. The TSFPs of the invention show extremely enhanced levels of stability and thermotolerance. In one case, for example, a TSFP of the invention is so stable it can be heated to 99.degree. C. for short periods of time without denaturing, and retains 85% of its fluorescence when heated to 80.degree. C. for several minutes. The invention also provides a method for generating stability-enhanced variants of a protein, including but not limited to fluorescent proteins.

  14. Fluorescent discharge lamp

    NASA Technical Reports Server (NTRS)

    Mukai, E.; Otsuka, H.; Nomi, K.; Honmo, I.

    1982-01-01

    A rapidly illuminating fluorescent lamp 1,200 mm long and 32.5 mm in diameter with an interior conducting strip which is compatible with conventional fixtures and ballasts is described. The fluorescent lamp is composed of a linear glass tube, electrodes sealed at both ends, mercury and raregas sealed in the glass tube, a fluorescent substance clad on the inner walls of the glass tube, and a clad conducting strip extending the entire length of the glass tube in the axial direction on the inner surface of the tube.

  15. Super resolution fluorescence microscopy

    PubMed Central

    Huang, Bo; Bates, Mark; Zhuang, Xiaowei

    2010-01-01

    Achieving a spatial resolution that is not limited by the diffraction of light, recent developments of super-resolution fluorescence microscopy techniques allow the observation of many biological structures not resolvable in conventional fluorescence microscopy. New advances in these techniques now give them the ability to image three-dimensional (3D) structures, measure interactions by multicolor colocalization, and record dynamic processes in living cells at the nanometer scale. It is anticipated that super-resolution fluorescence microscopy will become a widely used tool for cell and tissue imaging to provide previously unobserved details of biological structures and processes. PMID:19489737

  16. Multimodal light-sheet microscopy for fluorescence live imaging

    NASA Astrophysics Data System (ADS)

    Oshima, Y.; Kajiura-Kobayashi, H.; Nonaka, S.

    2012-03-01

    Light-sheet microscopy, it is known as single plane illumination microscope (SPIM), is a fluorescence imaging technique which can avoid phototoxic effects to living cells and gives high contrast and high spatial resolution by optical sectioning with light-sheet illumination in developmental biology. We have been developed a multifunctional light-sheet fluorescence microscopy system with a near infrared femto-second fiber laser, a high sensitive image sensor and a high throughput spectrometer. We performed that multiphoton fluorescence images of a transgenic fish and a mouse embryo were observed on the light-sheet microscope. As the results, two photon images with high contrast and high spatial resolution were successfully obtained in the microscopy system. The system has multimodality, not only mutiphoton fluorescence imaging, but also hyperspectral imaging, which can be applicable to fluorescence unmixing analysis and Raman imaging. It enables to obtain high specific and high throughput molecular imaging in vivo and in vitro.

  17. Use of fluorescence lifetime imaging (FLIM) for latent fingerprints detection

    NASA Astrophysics Data System (ADS)

    Wang, Peng; Chao, Zhi Xia; Seah, Leong K.; Murukeshan, Vadakke M.

    2005-04-01

    Fluorescence lifetime imaging (FLIM) in frequency domain enables the mapping of the spatial distribution of fluorescence lifetimes of a specimen. FLIM can provide unique information about fluorophores and hence is widely used in biology and for medical diagnostics. In this paper, a theoretical analysis for the fluorescence lifetime determination of latent fingerprint samples is described, which is followed by the feasibility study of using FLIM in frequency domain for latent fingerprints detection. Experiments are carried out with fingerprint on green paper substrate and postcard substrate treated with certain fluorescent powder. The total phase lag and demodulation factor are calculated to determine the lifetimes pixel by pixel. The resulting fluorescence lifetime image of fingerprint revealed an improvement in the contrast, and was able to detect the latent fingerprint clearly.

  18. Resonance Fluorescence from an Artificial Atom in Squeezed Vacuum

    NASA Astrophysics Data System (ADS)

    Toyli, D. M.; Eddins, A. W.; Boutin, S.; Puri, S.; Hover, D.; Bolkhovsky, V.; Oliver, W. D.; Blais, A.; Siddiqi, I.

    2016-07-01

    We present an experimental realization of resonance fluorescence in squeezed vacuum. We strongly couple microwave-frequency squeezed light to a superconducting artificial atom and detect the resulting fluorescence with high resolution enabled by a broadband traveling-wave parametric amplifier. We investigate the fluorescence spectra in the weak and strong driving regimes, observing up to 3.1 dB of reduction of the fluorescence linewidth below the ordinary vacuum level and a dramatic dependence of the Mollow triplet spectrum on the relative phase of the driving and squeezed vacuum fields. Our results are in excellent agreement with predictions for spectra produced by a two-level atom in squeezed vacuum [Phys. Rev. Lett. 58, 2539 (1987)], demonstrating that resonance fluorescence offers a resource-efficient means to characterize squeezing in cryogenic environments.

  19. Enabling individualized therapy through nanotechnology

    PubMed Central

    Sakamoto, Jason H.; van de Ven, Anne L.; Godin, Biana; Blanco, Elvin; Serda, Rita E.; Grattoni, Alessandro; Ziemys, Arturas; Bouamrani, Ali; Hu, Tony; Ranganathan, Shivakumar I.; De Rosa, Enrica; Martinez, Jonathan O.; Smid, Christine A.; Buchanan, Rachel M.; Lee, Sei-Young; Srinivasan, Srimeenakshi; Landry, Matthew; Meyn, Anne; Tasciotti, Ennio; Liu, Xuewu; Decuzzi, Paolo; Ferrari, Mauro

    2010-01-01

    Individualized medicine is the healthcare strategy that rebukes the idiomatic dogma of ‘losing sight of the forest for the trees’. We are entering a new era of healthcare where it is no longer acceptable to develop and market a drug that is effective for only 80% of the patient population. The emergence of “-omic” technologies (e.g. genomics, transcriptomics, proteomics, metabolomics) and advances in systems biology are magnifying the deficiencies of standardized therapy, which often provide little treatment latitude for accommodating patient physiologic idiosyncrasies. A personalized approach to medicine is not a novel concept. Ever since the scientific community began unraveling the mysteries of the genome, the promise of discarding generic treatment regimens in favor of patient-specific therapies became more feasible and realistic. One of the major scientific impediments of this movement towards personalized medicine has been the need for technological enablement. Nanotechnology is projected to play a critical role in patient-specific therapy; however, this transition will depend heavily upon the evolutionary development of a systems biology approach to clinical medicine based upon “-omic” technology analysis and integration. This manuscript provides a forward looking assessment of the promise of nanomedicine as it pertains to individualized medicine and establishes a technology “snapshot” of the current state of nano-based products over a vast array of clinical indications and range of patient specificity. Other issues such as market driven hurdles and regulatory compliance reform are anticipated to “self-correct” in accordance to scientific advancement and healthcare demand. These peripheral, non-scientific concerns are not addressed at length in this manuscript; however they do exist, and their impact to the paradigm shifting healthcare transformation towards individualized medicine will be critical for its success. PMID:20045055

  20. Solar Glitter -- Microsystems Enabled Photovoltaics

    NASA Astrophysics Data System (ADS)

    Nielson, Gregory N.

    2012-02-01

    Many products have significantly benefitted from, or been enabled by, the ability to manufacture structures at an ever decreasing length scale. Obvious examples of this include integrated circuits, flat panel displays, micro-scale sensors, and LED lighting. These industries have benefited from length scale effects in terms of improved performance, reduced cost, or new functionality (or a combination of these). In a similar manner, we are working to take advantage of length scale effects that exist within solar photovoltaic (PV) systems. While this is a significant step away from traditional approaches to solar power systems, the benefits in terms of new functionality, improved performance, and reduced cost for solar power are compelling. We are exploring scale effects that result from the size of the solar cells within the system. We have developed unique cells of both crystalline silicon and III-V materials that are very thin (5-20 microns thick) and have very small lateral dimensions (on the order of hundreds of microns across). These cells minimize the amount of expensive semiconductor material required for the system, allow improved cell performance, and provide an expanded design space for both module and system concepts allowing optimized power output and reduced module and balance of system costs. Furthermore, the small size of the cells allows for unique high-efficiency, high-flexibility PV panels and new building-integrated PV options that are currently unavailable. These benefits provide a pathway for PV power to become cost competitive with grid power and allow unique power solutions independent of grid power.

  1. Advances in fluorescence labeling strategies for dynamic cellular imaging

    PubMed Central

    Dean, Kevin M; Palmer, Amy E

    2014-01-01

    Synergistic advances in optical physics, probe design, molecular biology, labeling techniques and computational analysis have propelled fluorescence imaging into new realms of spatiotemporal resolution and sensitivity. This review aims to discuss advances in fluorescent probes and live-cell labeling strategies, two areas that remain pivotal for future advances in imaging technology. Fluorescent protein– and bio-orthogonal–based methods for protein and RNA imaging are discussed as well as emerging bioengineering techniques that enable their expression at specific genomic loci (for example, CRISPR and TALENs). Important attributes that contribute to the success of each technique are emphasized, providing a guideline for future advances in dynamic live-cell imaging. PMID:24937069

  2. Highly selective fluorescence imaging of zinc distribution in HeLa cells and Arabidopsis using a naphthalene-based fluorescent probe.

    PubMed

    Lee, Ji Ha; Lee, Jin Hyeok; Jung, Sung Ho; Hyun, Tae Kyung; Feng, Mingxiao; Kim, Jae-Yean; Lee, Jae-Hong; Lee, Hoyeon; Kim, Jong Seung; Kang, Chulhun; Kwon, Ki-Young; Jung, Jong Hwa

    2015-05-01

    2-(N,N-Dimethylamino)naphthalene-based probe 1 was found to exhibit a dramatic enhancement in fluorescence upon addition of Zn(2+), but not with any other metal ions. Probe 1 as a chemoprobe enabled high-resolution fluorescence imaging of zinc ions in HeLa cells and Arabidopsis.

  3. CD56dimCD57+NKG2C+ NK cell expansion is associated with reduced leukemia relapse after reduced intensity HCT.

    PubMed

    Cichocki, F; Cooley, S; Davis, Z; DeFor, T E; Schlums, H; Zhang, B; Brunstein, C G; Blazar, B R; Wagner, J; Diamond, D J; Verneris, M R; Bryceson, Y T; Weisdorf, D J; Miller, J S

    2016-02-01

    We have recently described a specialized subset of human natural killer (NK) cells with a CD56(dim)CD57(+)NKG2C(+) phenotype that expand specifically in response to cytomegalovirus (CMV) reactivation in hematopoietic cell transplant (HCT) recipients and exhibit properties characteristic of adaptive immunity. We hypothesize that these cells mediate relapse protection and improve post-HCT outcomes. In 674 allogeneic HCT recipients, we found that those who reactivated CMV had lower leukemia relapse (26% (17-35%), P=0.05) and superior disease-free survival (DFS) (55% (45-65%) P=0.04) 1 year after reduced intensity conditioning (RIC) compared with CMV seronegative recipients who experienced higher relapse rates (35% (27-43%)) and lower DFS (46% (38-54%)). This protective effect was independent of age and graft-vs-host disease and was not observed in recipients who received myeloablative regimens. Analysis of the reconstituting NK cells demonstrated that CMV reactivation is associated with both higher frequencies and greater absolute numbers of CD56(dim)CD57(+)NKG2C(+) NK cells, particularly after RIC HCT. Furthermore, expansion of these cells at 6 months posttransplant independently trended toward a lower 2-year relapse risk. Together, our data suggest that the protective effect of CMV reactivation on posttransplant relapse is in part driven by adaptive NK cell responses. PMID:26416461

  4. Bioluminescence of a firefly pupa: involvement of a luciferase isotype in the dim glow of pupae and eggs in the Japanese firefly, Luciola lateralis.

    PubMed

    Oba, Yuichi; Furuhashi, Mana; Bessho, Manabu; Sagawa, Shingo; Ikeya, Haruyoshi; Inouye, Satoshi

    2013-05-01

    We isolated cDNA for a luciferase isotype, LlLuc2, from the ovary of the Japanese firefly, Luciola lateralis. The gene product LlLuc2 showed 59% amino acid identity with LlLuc1, which had been isolated from the adult L. lateralis lantern. Molecular phylogenetic analysis indicated that LlLuc2 is an orthologue of LcLuc2 from Luciola cruciata. The spectral maxima of the luminescence by recombinant LlLuc1 and LlLuc2 were 550 and 539 nm, respectively. Quantitative PCR analysis revealed that LlLuc1 was expressed predominantly in larvae and adults, and LlLuc2 was expressed in eggs and pupae, which glow dimly, and we found that the in vivo luminescence spectra of the egg and pupa in L. lateralis were in good agreement with the in vitro luminescence spectrum by LlLuc2. These results suggest that, in L. lateralis, LlLuc1 is responsible for the yellowish luminescence of larval and adult lanterns, and LlLuc2 is responsible for the dim, greenish glow of eggs and whole pupae. Similar results were obtained in L. cruciata.

  5. Current crowding impact at spatially and temporarily resolved thermal characters of large-area AlGaInP light emitting diodes operating in dimming/flashing modes

    NASA Astrophysics Data System (ADS)

    Malyutenko, V. K.; Podoltsev, A. D.; Malyutenko, O. Yu.

    2015-10-01

    By exploring spatially (μm-scale) and temporarily (ms-scale) resolved light and 8-12 μm thermal imaging analyses, we demonstrate how current crowding alternates the thermal parameters of light emitting diodes (LEDs) operating in dimming/flashing mode. For example, in AlGaInP/GaAs high-current (I ≥ 1 A) large-area (≥1 mm2) LEDs, we measured the thermal time constant (2.5 ms), heat diffusion length (110 μm), current crowding length (≤75 μm), thermal diffusivity (0.08 cm2/s) of GaAs substrate, and current-dependent thermal patterns taken from the front and sidewall facet of chips. We discovered that even at I = 100 mA emitting ships are already divided by two regions with different temperatures, small area high-temperature central regions (effective volumes) with high current density and larger area lower-temperature peripheral regions with much lower current density. The experiments evidence that the simplified computer simulations of dimming mode based on mean chip temperature, mean thermal resistance, and average current density, as well as temperature-independent ABC-modeling must be regarded with skepticism.

  6. Fluorescent and Bioluminescent Reporter Myxoviruses

    PubMed Central

    Rostad, Christina A.; Currier, Michael C.; Moore, Martin L.

    2016-01-01

    The advent of virus reverse genetics has enabled the incorporation of genetically encoded reporter proteins into replication-competent viruses. These reporters include fluorescent proteins which have intrinsic chromophores that absorb light and re-emit it at lower wavelengths, and bioluminescent proteins which are luciferase enzymes that react with substrates to produce visible light. The incorporation of these reporters into replication-competent viruses has revolutionized our understanding of molecular virology and aspects of viral tropism and transmission. Reporter viruses have also enabled the development of high-throughput assays to screen antiviral compounds and antibodies and to perform neutralization assays. However, there remain technical challenges with the design of replication-competent reporter viruses, and each reporter has unique advantages and disadvantages for specific applications. This review describes currently available reporters, design strategies for incorporating reporters into replication-competent paramyxoviruses and orthomyxoviruses, and the variety of applications for which these tools can be utilized both in vitro and in vivo. PMID:27527209

  7. Fluorescent and Bioluminescent Reporter Myxoviruses.

    PubMed

    Rostad, Christina A; Currier, Michael C; Moore, Martin L

    2016-01-01

    The advent of virus reverse genetics has enabled the incorporation of genetically encoded reporter proteins into replication-competent viruses. These reporters include fluorescent proteins which have intrinsic chromophores that absorb light and re-emit it at lower wavelengths, and bioluminescent proteins which are luciferase enzymes that react with substrates to produce visible light. The incorporation of these reporters into replication-competent viruses has revolutionized our understanding of molecular virology and aspects of viral tropism and transmission. Reporter viruses have also enabled the development of high-throughput assays to screen antiviral compounds and antibodies and to perform neutralization assays. However, there remain technical challenges with the design of replication-competent reporter viruses, and each reporter has unique advantages and disadvantages for specific applications. This review describes currently available reporters, design strategies for incorporating reporters into replication-competent paramyxoviruses and orthomyxoviruses, and the variety of applications for which these tools can be utilized both in vitro and in vivo. PMID:27527209

  8. Candida, fluorescent stain (image)

    MedlinePlus

    This microscopic film shows a fluorescent stain of Candida. Candida is a yeast (fungus) that causes mild disease, but in immunocompromised individuals it may cause life-threatening illness. (Image ...

  9. Fluorescent filtered electrophosphorescence

    DOEpatents

    Forrest, Stephen R.; Sun, Yiru; Giebink, Noel; Thompson, Mark E.

    2009-01-06

    The present invention relates to organic light emitting devices (OLEDs), and more specifically to OLEDS that emit light using a combination of fluorescent emitters and phosphorescent emitters for the efficient utilization of all of the electrically generated excitons.

  10. Fluorescent filtered electrophosphorescence

    DOEpatents

    Forrest, Stephen; Sun, Yiru; Giebink, Noel; Thompson, Mark E.

    2010-08-03

    The present invention relates to organic light emitting devices (OLEDs), and more specifically to OLEDS that emit light using a combination of fluorescent emitters and phosphorescent emitters for the efficient utilization of all of the electrically generated excitons.

  11. Atmospheric Fluorescence Yield

    NASA Technical Reports Server (NTRS)

    Adams, James H., Jr.; Christl, M. J.; Fountain, W. F.; Gregory, J. C.; Martens, K.; Sokolsky, P.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    Several existing and planned experiments estimate the energies of ultra-high energy cosmic rays from air showers using the atmospheric fluorescence from these showers. Accurate knowledge of the conversion from atmospheric fluorescence to energy loss by ionizing particles in the atmosphere is key to this technique. In this paper we discuss a small balloon-borne instrument to make the first in situ measurements versus altitude of the atmospheric fluorescence yield. The instrument can also be used in the lab to investigate the dependence of the fluorescence yield in air on temperature, pressure and the concentrations of other gases that present in the atmosphere. The results can be used to explore environmental effects on and improve the accuracy of cosmic ray energy measurements for existing ground-based experiments and future space-based experiments.

  12. Fluorescent eye test (image)

    MedlinePlus

    The fluorescent eye test is useful in determining if there is a scratch or other problem with the surface ... has thoroughly covered the eye a cobalt blue light is then directed on the eye. The light ...

  13. Infrared study of H 1743-322 in outburst: a radio-quiet and NIR-dim microquasar

    NASA Astrophysics Data System (ADS)

    Chaty, S.; Muñoz Arjonilla, A. J.; Dubus, G.

    2015-05-01

    the Galactic bulge. Conclusions: These OIR photometric and spectroscopic observations of the microquasar H 1743-322, which are the first of this source to be published in a broad multiwavelength context, allow us to unambiguously identify two spectra of different origins in the OIR domain, evolving from optically thick thermal emission to optically thin synchrotron emission toward longer wavelengths. Comparing these OIR observations with other black hole candidates suggests that H 1743-322 behaves like a radio-quiet and NIR-dim black hole in the low, hard state. This study will be useful when quantitatively comparing the overall contribution of the compact jet and accretion flow in the energy budget of microquasars. Based on observations collected at the European Southern Observatory, Chile, through programs 071.D-0073, 073.D-0341 and 081.D-0401.

  14. Fluorescent Applications to Crystallization

    NASA Technical Reports Server (NTRS)

    Pusey, Marc L.; Forsythe, Elizabeth; Achari, Aniruddha

    2006-01-01

    By covalently modifying a subpopulation, less than or equal to 1%, of a macromolecule with a fluorescent probe, the labeled material will add to a growing crystal as a microheterogeneous growth unit. Labeling procedures can be readily incorporated into the final stages of purification, and tests with model proteins have shown that labeling u to 5 percent of the protein molecules does not affect the X-ray data quality obtained . The presence of the trace fluorescent label gives a number of advantages. Since the label is covalently attached to the protein molecules, it "tracks" the protein s response to the crystallization conditions. The covalently attached probe will concentrate in the crystal relative to the solution, and under fluorescent illumination crystals show up as bright objects against a darker background. Non-protein structures, such as salt crystals, do not show up under fluorescent illumination. Crystals have the highest protein concentration and are readily observed against less bright precipitated phases, which under white light illumination may obscure the crystals. Automated image analysis to find crystals should be greatly facilitated, without having to first define crystallization drop boundaries as the protein or protein structures is all that shows up. Fluorescence intensity is a faster search parameter, whether visually or by automated methods, than looking for crystalline features. Preliminary tests, using model proteins, indicates that we can use high fluorescence intensity regions, in the absence of clear crystalline features or "hits", as a means for determining potential lead conditions. A working hypothesis is that more rapid amorphous precipitation kinetics may overwhelm and trap more slowly formed ordered assemblies, which subsequently show up as regions of brighter fluorescence intensity. Experiments are now being carried out to test this approach using a wider range, of proteins. The trace fluorescently labeled crystals will also

  15. Epi-Fluorescence Microscopy

    PubMed Central

    Webb, Donna J.; Brown, Claire M.

    2012-01-01

    Epi-fluorescence microscopy is available in most life sciences research laboratories, and when optimized can be a central laboratory tool. In this chapter, the epi-fluorescence light path is introduced and the various components are discussed in detail. Recommendations are made for incident lamp light sources, excitation and emission filters, dichroic mirrors, objective lenses, and charge-coupled device (CCD) cameras in order to obtain the most sensitive epi-fluorescence microscope. The even illumination of metal-halide lamps combined with new “hard” coated filters and mirrors, a high resolution monochrome CCD camera, and a high NA objective lens are all recommended for high resolution and high sensitivity fluorescence imaging. Recommendations are also made for multicolor imaging with the use of monochrome cameras, motorized filter turrets, individual filter cubes, and corresponding dyes that are the best choice for sensitive, high resolution multicolor imaging. Images should be collected using Nyquist sampling and should be corrected for background intensity contributions and nonuniform illumination across the field of view. Photostable fluorescent probes and proteins that absorb a lot of light (i.e., high extinction co-efficients) and generate a lot of fluorescence signal (i.e., high quantum yields) are optimal. A neuronal immune-fluorescence labeling protocol is also presented. Finally, in order to maximize the utility of sensitive wide-field microscopes and generate the highest resolution images with high signal-to-noise, advice for combining wide-field epi-fluorescence imaging with restorative image deconvolution is presented. PMID:23026996

  16. The Schizosaccharomyces pombe dim1+ Gene Interacts with the Anaphase-Promoting Complex or Cyclosome (APC/C) Component lid1+ and Is Required for APC/C Function

    PubMed Central

    Berry, Lynne D.; Feoktistova, Anna; Wright, Melanie D.; Gould, Kathleen L.

    1999-01-01

    The Schizosaccharomyces pombe dim1+ gene is required for entry into mitosis and for chromosome segregation during mitosis. To further understand dim1p function, we undertook a synthetic lethal screen with the temperature-sensitive dim1-35 mutant and isolated lid (for lethal in dim1-35) mutants. Here, we describe the temperature-sensitive lid1-6 mutant. At the restrictive temperature of 36°C, lid1-6 mutant cells arrest with a “cut” phenotype similar to that of cut4 and cut9 mutants. An epitope-tagged version of lid1p is a component of a multiprotein ∼20S complex; the presence of lid1p in this complex depends upon functional cut9+. lid1p-myc coimmunoprecipitates with several other proteins, including cut9p and nuc2p, and the presence of cut9p in a 20S complex depends upon the activity of lid1+. Further, lid1+ function is required for the multiubiquitination of cut2p, an anaphase-promoting complex or cyclosome (APC/C) target. Thus, lid1p is a component of the S. pombe APC/C. In dim1 mutants, the abundances of lid1p and the APC/C complex decline significantly, and the ubiquitination of an APC/C target is abolished. These data suggest that at least one role of dim1p is to maintain or establish the steady-state level of the APC/C. PMID:10082519

  17. A Single Fluorescent Probe to Visualize Hydrogen Sulfide and Hydrogen Polysulfides with Different Fluorescence Signals.

    PubMed

    Chen, Wei; Pacheco, Armando; Takano, Yoko; Day, Jacob J; Hanaoka, Kenjiro; Xian, Ming

    2016-08-16

    Hydrogen sulfide (H2 S) and hydrogen polysulfides (H2 Sn , n>1) are endogenous regulators of many physiological processes. In order to better understand the symbiotic relationship and cellular cross-talk between H2 S and H2 Sn , it is highly desirable to develop single fluorescent probes which enable dual-channel discrimination between H2 S and H2 Sn . Herein, we report the rational design, synthesis, and evaluation of the first dual-detection fluorescent probe DDP-1 that can visualize H2 S and H2 Sn with different fluorescence signals. The probe showed high selectivity and sensitivity to H2 S and H2 Sn in aqueous media and in cells. PMID:27410794

  18. Phytoplankton-Fluorescence-Lifetime Vertical Profiler

    NASA Technical Reports Server (NTRS)

    Fernandez, Salvador M.; Guignon, Ernest F.; St. Louis, Ernest

    2004-01-01

    A battery-operated optoelectronic instrument is designed to be lowered into the ocean to measure the intensity and lifetime of fluorescence of chlorophyll A in marine phytoplankton as a function of depth from 0 to 300 m. Fluorescence lifetimes are especially useful as robust measures of photosynthetic productivity of phytoplankton and of physical and chemical mechanisms that affect photosynthesis. The knowledge of photosynthesis in phytoplankton gained by use of this and related instruments is expected to contribute to understanding of global processes that control the time-varying fluxes of carbon and associated biogenic elements in the ocean. The concentration of chlorophyll in the ocean presents a major detection challenge because in order to obtain accurate values of photosynthetic parameters, the intensity of light used to excite fluorescence must be kept very low so as not to disturb the photosynthetic system. Several innovations in fluorometric instrumentation were made in order to make it possible to reach the required low detection limit. These innovations include a highly efficient optical assembly with an integrated flow-through sample interface, and a high-gain, low-noise electronic detection subsystem. The instrument also incorporates means for self-calibration during operation, and electronic hardware and software for control, acquisition and analysis of data, and communications. The electronic circuitry is highly miniaturized and designed to minimize power demand. The instrument is housed in a package that can withstand the water pressure at the maximum depth of 300 m. A light-emitting diode excites fluorescence in the sample flow cell, which is placed at one focal point of an ellipsoidal reflector. A photomultiplier tube is placed at the other focal point. This optical arrangement enables highly efficient collection of fluorescence emitted over all polar directions. Fluorescence lifetime is measured indirectly, by use of a technique based on the

  19. Latest methods of fluorescence-based protein crystal identification

    SciTech Connect

    Meyer, Arne; Betzel, Christian

    2015-01-28

    Fluorescence, whether intrinsic or by using trace fluorescent labeling, can be a powerful aid in macromolecule crystallization. Its use in screening for crystals is discussed here. Successful protein crystallization screening experiments are dependent upon the experimenter being able to identify positive outcomes. The introduction of fluorescence techniques has brought a powerful and versatile tool to the aid of the crystal grower. Trace fluorescent labeling, in which a fluorescent probe is covalently bound to a subpopulation (<0.5%) of the protein, enables the use of visible fluorescence. Alternatively, one can avoid covalent modification and use UV fluorescence, exploiting the intrinsic fluorescent amino acids present in most proteins. By the use of these techniques, crystals that had previously been obscured in the crystallization drop can readily be identified and distinguished from amorphous precipitate or salt crystals. Additionally, lead conditions that may not have been obvious as such under white-light illumination can be identified. In all cases review of the screening plate is considerably accelerated, as the eye can quickly note objects of increased intensity.

  20. Multifunctional Magnetic-fluorescent Nanocomposites for Biomedical Applications

    NASA Astrophysics Data System (ADS)

    Corr, Serena A.; Rakovich, Yury P.; Gun'ko, Yurii K.

    2008-03-01

    Nanotechnology is a fast-growing area, involving the fabrication and use of nano-sized materials and devices. Various nanocomposite materials play a number of important roles in modern science and technology. Magnetic and fluorescent inorganic nanoparticles are of particular importance due to their broad range of potential applications. It is expected that the combination of magnetic and fluorescent properties in one nanocomposite would enable the engineering of unique multifunctional nanoscale devices, which could be manipulated using external magnetic fields. The aim of this review is to present an overview of bimodal “two-in-one” magnetic-fluorescent nanocomposite materials which combine both magnetic and fluorescent properties in one entity, in particular those with potential applications in biotechnology and nanomedicine. There is a great necessity for the development of these multifunctional nanocomposites, but there are some difficulties and challenges to overcome in their fabrication such as quenching of the fluorescent entity by the magnetic core. Fluorescent-magnetic nanocomposites include a variety of materials including silica-based, dye-functionalised magnetic nanoparticles and quantum dots-magnetic nanoparticle composites. The classification and main synthesis strategies, along with approaches for the fabrication of fluorescent-magnetic nanocomposites, are considered. The current and potential biomedical uses, including biological imaging, cell tracking, magnetic bioseparation, nanomedicine and bio- and chemo-sensoring, of magnetic-fluorescent nanocomposites are also discussed.

  1. Multifunctional Magnetic-fluorescent Nanocomposites for Biomedical Applications

    PubMed Central

    2008-01-01

    Nanotechnology is a fast-growing area, involving the fabrication and use of nano-sized materials and devices. Various nanocomposite materials play a number of important roles in modern science and technology. Magnetic and fluorescent inorganic nanoparticles are of particular importance due to their broad range of potential applications. It is expected that the combination of magnetic and fluorescent properties in one nanocomposite would enable the engineering of unique multifunctional nanoscale devices, which could be manipulated using external magnetic fields. The aim of this review is to present an overview of bimodal “two-in-one” magnetic-fluorescent nanocomposite materials which combine both magnetic and fluorescent properties in one entity, in particular those with potential applications in biotechnology and nanomedicine. There is a great necessity for the development of these multifunctional nanocomposites, but there are some difficulties and challenges to overcome in their fabrication such as quenching of the fluorescent entity by the magnetic core. Fluorescent-magnetic nanocomposites include a variety of materials including silica-based, dye-functionalised magnetic nanoparticles and quantum dots-magnetic nanoparticle composites. The classification and main synthesis strategies, along with approaches for the fabrication of fluorescent-magnetic nanocomposites, are considered. The current and potential biomedical uses, including biological imaging, cell tracking, magnetic bioseparation, nanomedicine and bio- and chemo-sensoring, of magnetic-fluorescent nanocomposites are also discussed.

  2. Fluorescence photoactivation by intermolecular proton transfer.

    PubMed

    Swaminathan, Subramani; Petriella, Marco; Deniz, Erhan; Cusido, Janet; Baker, James D; Bossi, Mariano L; Raymo, Françisco M

    2012-10-11

    We designed a strategy to activate fluorescence under the influence of optical stimulations based on the intermolecular transfer of protons. Specifically, the illumination of a 2-nitrobenzyl derivative at an activating wavelength is accompanied by the release of hydrogen bromide. In turn, the photogenerated acid encourages the opening of an oxazine ring embedded within a halochromic compound. This structural transformation extends the conjugation of an adjacent coumarin fluorophore and enables its absorption at an appropriate excitation wavelength. Indeed, this bimolecular system offers the opportunity to activate fluorescence in liquid solutions, within rigid matrixes and inside micellar assemblies, relying on the interplay of activating and exciting beams. Furthermore, this strategy permits the permanent imprinting of fluorescent patterns on polymer films, the monitoring of proton diffusion within such materials in real time on a millisecond time scale, and the acquisition of images with spatial resolution at the nanometer level. Thus, our operating principles for fluorescence activation can eventually lead to the development of valuable photoswitchable probes for imaging applications and versatile mechanisms for the investigation of proton transport. PMID:22994311

  3. Nine New Fluorescent Probes

    NASA Astrophysics Data System (ADS)

    Lin, Tsung-I.; Jovanovic, Misa V.; Dowben, Robert M.

    1989-06-01

    Absorption and fluorescence spectroscopic studies are reported here for nine new fluorescent probes recently synthesized in our laboratories: four pyrene derivatives with substituents of (i) 1,3-diacetoxy-6,8-dichlorosulfonyl, (ii) 1,3-dihydroxy-6,8-disodiumsulfonate, (iii) 1,3-disodiumsulfonate, and (iv) l-ethoxy-3,6,8-trisodiumsulfonate groups, and five [7-julolidino] coumarin derivatives with substituents of (v) 3-carboxylate-4-methyl, (vi) 3- methylcarboxylate, (vii) 3-acetate-4-methyl, (viii) 3-propionate-4-methyl, and (ix) 3-sulfonate-4-methyl groups. Pyrene compounds i and ii and coumarin compounds v and vi exhibit interesting absorbance and fluorescence properties: their absorption maxima are red shifted compared to the parent compound to the blue-green region, and the band width broadens considerably. All four blue-absorbing dyes fluoresce intensely in the green region, and the two pyrene compounds emit at such long wavelengths without formation of excimers. The fluorescence properties of these compounds are quite environment-sensitive: considerable spectral shifts and fluorescence intensity changes have been observed in the pH range from 3 to 10 and in a wide variety of polar and hydrophobic solvents with vastly different dielectric constants. The high extinction and fluorescence quantum yield of these probes make them ideal fluorescent labeling reagents for proteins, antibodies, nucleic acids, and cellular organelles. The pH and hydrophobicity-dependent fluorescence changes can be utilized as optical pH and/or hydrophobicity indicators for mapping environmental difference in various cellular components in a single cell. Since all nine probes absorb in the UV, but emit at different wavelengths in the visible, these two groups of compounds offer an advantage of utilizing a single monochromatic light source (e.g., a nitrogen laser) to achieve multi-wavelength detection for flow cytometry application. As a first step to explore potential application in

  4. Fluorescent image tracking velocimeter

    DOEpatents

    Shaffer, Franklin D.

    1994-01-01

    A multiple-exposure fluorescent image tracking velocimeter (FITV) detects and measures the motion (trajectory, direction and velocity) of small particles close to light scattering surfaces. The small particles may follow the motion of a carrier medium such as a liquid, gas or multi-phase mixture, allowing the motion of the carrier medium to be observed, measured and recorded. The main components of the FITV include: (1) fluorescent particles; (2) a pulsed fluorescent excitation laser source; (3) an imaging camera; and (4) an image analyzer. FITV uses fluorescing particles excited by visible laser light to enhance particle image detectability near light scattering surfaces. The excitation laser light is filtered out before reaching the imaging camera allowing the fluoresced wavelengths emitted by the particles to be detected and recorded by the camera. FITV employs multiple exposures of a single camera image by pulsing the excitation laser light for producing a series of images of each particle along its trajectory. The time-lapsed image may be used to determine trajectory and velocity and the exposures may be coded to derive directional information.

  5. Fluorescence analyzer for lignin

    SciTech Connect

    Berthold, J.W.; Malito, M.L.; Jeffers, L.

    1993-06-01

    An apparatus for measuring lignin concentration with time resolved fluorescence in an undiluted wood pulp or black liquor sample, on a real-time, in situ basis is described, comprising: light source means for applying excitation light pulses at a selected wavelength and at known time intervals to the undiluted sample for causing the lignin concentration to produce fluorescent emission light with a fluorescence intensity that monotonically decreases in a quenched fluorescence regime; light detector means for measuring the emission light at the known time intervals and establishing signals indicative thereof; switching means for turning said light detector means on at precise specified time intervals after each excitation light pulse; and signal processing means connected to the light source means and the light detector means for comparing intensities of the emission light from the lignin in the quenched fluorescence regime to the intensities of the excitation light pulses on a time resolved basis for providing a measurement of the lignin concentration in the undiluted sample as a function of the time resolved emission light intensity.

  6. Fluorenyl benzothiadiazole and benzoselenadiazole near-IR fluorescent probes for two-photon fluorescence imaging (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Belfield, Kevin D.; Yao, Sheng; Kim, Bosung; Yue, Xiling

    2016-03-01

    Imaging biological samples with two-photon fluorescence (2PF) microscopy has the unique advantage of resulting high contrast 3D resolution subcellular image that can reach up to several millimeters depth. 2PF probes that absorb and emit at near IR region need to be developed. Two-photon excitation (2PE) wavelengths are less concerned as 2PE uses wavelengths doubles the absorption wavelength of the probe, which means 2PE wavelengths for probes even with absorption at visible wavelength will fall into NIR region. Therefore, probes that fluoresce at near IR region with high quantum yields are needed. A series of dyes based on 5-thienyl-2, 1, 3-benzothiadiazole and 5-thienyl-2, 1, 3-benzoselenadiazole core were synthesized as near infrared two-photon fluorophores. Fluorescence maxima wavelengths as long as 714 nm and fluorescence quantum yields as high as 0.67 were achieved. The fluorescence quantum yields of the dyes were nearly constant, regardless of solvents polarity. These diazoles exhibited large Stokes shift (<114nm), high two-photon absorption cross sections (up to 2,800 GM), and high two-photon fluorescence figure of merit (FM , 1.04×10-2 GM). Cells incubated on a 3D scaffold with one of the new probes (encapsulated in Pluronic micelles) exhibited bright fluorescence, enabling 3D two-photon fluorescence imaging to a depth of 100 µm.

  7. Fixation-resistant photoactivatable fluorescent proteins for correlative light and electron microscopy

    PubMed Central

    Paez Segala, Maria G.; Sun, Mei G.; Shtengel, Gleb; Viswanathan, Sarada; Baird, Michelle A.; Macklin, John J.; Patel, Ronak; Allen, John R.; Howe, Elizabeth S.; Piszczek, Grzegorz; Hess, Harald F.; Davidson, Michael W.; Wang, Yalin; Looger, Loren L.

    2014-01-01

    Fluorescent proteins facilitate a variety of imaging paradigms in live and fixed samples. However, they cease to function following heavy fixation, hindering advanced applications such as correlative light and electron microscopy. Here we report engineered variants of the photoconvertible Eos fluorescent protein that function normally in heavily fixed (0.5–1% OsO4), plastic resin-embedded samples, enabling correlative super-resolution fluorescence imaging and high-quality electron microscopy. PMID:25581799

  8. Optical fiber fluorescence and toxicity sensor

    NASA Astrophysics Data System (ADS)

    Merchant, David F.; Scully, Patricia J.; Edwards, Robert; Grabowski, Jozef

    1997-05-01

    We present a sensor for the continuous detection of fluorescent emissions from fluids. The sensor utilizes a patented optical fiber detection system to allow separation of the excitation and emission light without the need for optical filters, has a wide working range and has applications in process control, flow tracing and monitoring. The construction, principles and experimental results of the fiber sensor will be given. The authors have also developed a novel test for total toxicity of aquatic systems, the product of which is fluorescent, enabling the proposal of a rapid, continuous and low cost toxicity measurement system. The biochemistry of the test is easily adapted for all types of aquatic environment and expected pollution levels. Results for several heavy metal and organic contaminants, performed under laboratory conditions, are also presented.

  9. Fiberized fluorescent dye microtubes

    NASA Astrophysics Data System (ADS)

    Vladev, Veselin; Eftimov, Tinko

    2013-03-01

    In the present work we study the effect of the length of fluorescent dye-filled micro-capillaries on the fluorescence spectra. Two types of micro-capillaries have been studied: a 100 μm inner diameter fused silica capillary with a transparent coating and one of the holes of a fiber optic glass ferrule with 125 μm inner diameter. The tubes were filled with solutions of Rhodamine 6G dissolved in ethanol and then in glycerin. Experimental data show that the maximum fluorescence and the largest spectral widths are observed for a sample length of about 0.25 mm for the used concentration. This results show that miniature tunable fiberized dye lasers can be developed using available standard micro-and fibre-optic components.

  10. Ultrasound guided fluorescence tomography

    NASA Astrophysics Data System (ADS)

    Li, Baoqiang; Lesage, Frederic

    2012-10-01

    In this study, a hybrid-model imaging system combining fluorescence and ultrasound (US) was investigated with the motivation of providing structural priors towards improvement of fluorescence reconstruction. A single element transducer was scanned over the sample for anatomy. In the fluorescence part, a laser source was scanned over the sample with the emission received by an EMCCD camera. Synchronization was achieved by a pair of motorized linear stages. Structural information was derived from the US images and a profilometry and used to constrain reconstruction. In the reconstruction, we employed a GPU-based Monte Carlo simulation for forward modeling and a pattern-based method to take advantage of the huge dataset for the inverse problem. Performance of this system was validated with two phantoms with fluorophore inclusions. The results indicated that the fluorophore distribution could be accurately reconstructed. And the system has a potential for the future in-vivo study.

  11. Smartphone fluorescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Yu, Hojoeng; Tan, Yafang; Cunningham, Brian T.

    2014-03-01

    We demonstrate the first use of smartphone spectrophotometry for readout of fluorescence-based biological assays. We evaluated the smartphone fluorimeter in the context of a fluorescent molecular beacon (MB) assay for detection of a specific nucleic acid sequences in a liquid test sample. The capability of distinguishing a one-point mismatch is also demonstrated by detecting single-base mutation in target nucleic acids. Our approach offers a route towards portable biomolecular assays for viral/bacterial pathogens, disease biomarkers, and toxins.

  12. Smartphone fluorescence spectroscopy.

    PubMed

    Yu, Hojeong; Tan, Yafang; Cunningham, Brian T

    2014-09-01

    We demonstrate the first use of smartphone spectrophotometry for readout of fluorescence-based biological assays. We evaluated the smartphone fluorimeter in the context of a fluorescent molecular beacon (MB) assay for detection of specific nucleic acid sequences in a liquid test sample and compared performance against a conventional laboratory fluorimeter. The capability of distinguishing a one-point mismatch is also demonstrated by detecting single-base mutation in target nucleic acids. Our approach offers a route toward portable biomolecular assays for viral/bacterial pathogens, disease biomarkers, and toxins.

  13. Nanosecond fluorescence spectroscopy

    SciTech Connect

    Leskovar, B.

    1985-03-01

    This article is a summary of a short course lecture given in conjunction with the 1984 Nuclear Science Symposium. Measuring systems for nanosecond fluorescence spectroscopy using single-photon counting techniques are presented. These involve systems based on relaxation-type spark gap light pulser and synchronously pumped mode-locked dye lasers. Furthermore, typical characteristics and optimization of operating conditions of the critical components responsible for the system time resolution are discussed. A short comparison of the most important deconvolution methods for numerical analysis of experimental data is given particularly with respect to the signal-to-noise ratio of the fluorescence signal. 22 refs., 8 figs.

  14. Guidelines for application of fluorescent lamps in high-performance avionic backlight systems

    NASA Astrophysics Data System (ADS)

    Syroid, Daniel D.

    1997-07-01

    Fluorescent lamps have proven to be well suited for use in high performance avionic backlight systems as demonstrated by numerous production applications for both commercial and military cockpit displays. Cockpit display applications include: Boeing 777, new 737s, F-15, F-16, F-18, F-22, C- 130, Navy P3, NASA Space Shuttle and many others. Fluorescent lamp based backlights provide high luminance, high lumen efficiency, precision chromaticity and long life for avionic active matrix liquid crystal display applications. Lamps have been produced in many sizes and shapes. Lamp diameters range from 2.6 mm to over 20 mm and lengths for the larger diameter lamps range to over one meter. Highly convoluted serpentine lamp configurations are common as are both hot and cold cathode electrode designs. This paper will review fluorescent lamp operating principles, discuss typical requirements for avionic grade lamps, compare avionic and laptop backlight designs and provide guidelines for the proper application of lamps and performance choices that must be made to attain optimum system performance considering high luminance output, system efficiency, dimming range and cost.

  15. The evolution of genes encoding for green fluorescent proteins: insights from cephalochordates (amphioxus)

    PubMed Central

    Yue, Jia-Xing; Holland, Nicholas D.; Holland, Linda Z.; Deheyn, Dimitri D.

    2016-01-01

    Green Fluorescent Protein (GFP) was originally found in cnidarians, and later in copepods and cephalochordates (amphioxus) (Branchiostoma spp). Here, we looked for GFP-encoding genes in Asymmetron, an early-diverged cephalochordate lineage, and found two such genes closely related to some of the Branchiostoma GFPs. Dim fluorescence was found throughout the body in adults of Asymmetron lucayanum, and, as in Branchiostoma floridae, was especially intense in the ripe ovaries. Spectra of the fluorescence were similar between Asymmetron and Branchiostoma. Lineage-specific expansion of GFP-encoding genes in the genus Branchiostoma was observed, largely driven by tandem duplications. Despite such expansion, purifying selection has strongly shaped the evolution of GFP-encoding genes in cephalochordates, with apparent relaxation for highly duplicated clades. All cephalochordate GFP-encoding genes are quite different from those of copepods and cnidarians. Thus, the ancestral cephalochordates probably had GFP, but since GFP appears to be lacking in more early-diverged deuterostomes (echinoderms, hemichordates), it is uncertain whether the ancestral cephalochordates (i.e. the common ancestor of Asymmetron and Branchiostoma) acquired GFP by horizontal gene transfer (HGT) from copepods or cnidarians or inherited it from the common ancestor of copepods and deuterostomes, i.e. the ancestral bilaterians. PMID:27311567

  16. The evolution of genes encoding for green fluorescent proteins: insights from cephalochordates (amphioxus)

    NASA Astrophysics Data System (ADS)

    Yue, Jia-Xing; Holland, Nicholas D.; Holland, Linda Z.; Deheyn, Dimitri D.

    2016-06-01

    Green Fluorescent Protein (GFP) was originally found in cnidarians, and later in copepods and cephalochordates (amphioxus) (Branchiostoma spp). Here, we looked for GFP-encoding genes in Asymmetron, an early-diverged cephalochordate lineage, and found two such genes closely related to some of the Branchiostoma GFPs. Dim fluorescence was found throughout the body in adults of Asymmetron lucayanum, and, as in Branchiostoma floridae, was especially intense in the ripe ovaries. Spectra of the fluorescence were similar between Asymmetron and Branchiostoma. Lineage-specific expansion of GFP-encoding genes in the genus Branchiostoma was observed, largely driven by tandem duplications. Despite such expansion, purifying selection has strongly shaped the evolution of GFP-encoding genes in cephalochordates, with apparent relaxation for highly duplicated clades. All cephalochordate GFP-encoding genes are quite different from those of copepods and cnidarians. Thus, the ancestral cephalochordates probably had GFP, but since GFP appears to be lacking in more early-diverged deuterostomes (echinoderms, hemichordates), it is uncertain whether the ancestral cephalochordates (i.e. the common ancestor of Asymmetron and Branchiostoma) acquired GFP by horizontal gene transfer (HGT) from copepods or cnidarians or inherited it from the common ancestor of copepods and deuterostomes, i.e. the ancestral bilaterians.

  17. Interoperability of medical device information and the clinical applications: an HL7 RMIM based on the ISO/IEEE 11073 DIM.

    PubMed

    Yuksel, Mustafa; Dogac, Asuman

    2011-07-01

    Medical devices are essential to the practice of modern healthcare services. Their benefits will increase if clinical software applications can seamlessly acquire the medical device data. The need to represent medical device observations in a format that can be consumable by clinical applications has already been recognized by the industry. Yet, the solutions proposed involve bilateral mappings from the ISO/IEEE 11073 Domain Information Model (DIM) to specific message or document standards. Considering that there are many different types of clinical applications such as the electronic health record and the personal health record systems, the clinical workflows, and the clinical decision support systems each conforming to different standard interfaces, detailing a mapping mechanism for every one of them introduces significant work and, thus, limits the potential health benefits of medical devices. In this paper, to facilitate the interoperability of clinical applications and the medical device data, we use the ISO/IEEE 11073 DIM to derive an HL7 v3 Refined Message Information Model (RMIM) of the medical device domain from the HL7 v3 Reference Information Mode (RIM). This makes it possible to trace the medical device data back to a standard common denominator, that is, HL7 v3 RIM from which all the other medical domains under HL7 v3 are derived. Hence, once the medical device data are obtained in the RMIM format, it can easily be transformed into HL7-based standard interfaces through XML transformations because these interfaces all have their building blocks from the same RIM. To demonstrate this, we provide the mappings from the developed RMIM to some of the widely used HL7 v3-based standard interfaces.

  18. An Internet enabled impact limiter material database

    SciTech Connect

    Wix, S.; Kanipe, F.; McMurtry, W.

    1998-09-01

    This paper presents a detailed explanation of the construction of an interest enabled database, also known as a database driven web site. The data contained in the internet enabled database are impact limiter material and seal properties. The technique used in constructing the internet enabled database presented in this paper are applicable when information that is changing in content needs to be disseminated to a wide audience.

  19. Reactive polymer enables efficient in vivo bioorthogonal chemistry

    PubMed Central

    Devaraj, Neal K.; Thurber, Greg M.; Keliher, Edmund J.; Marinelli, Brett; Weissleder, Ralph

    2012-01-01

    There has been intense interest in the development of selective bioorthogonal reactions or “click” chemistry that can proceed in live animals. Until now however, most reactions still require vast surpluses of reactants because of steep temporal and spatial concentration gradients. Using computational modeling and design of pharmacokinetically optimized reactants, we have developed a predictable method for efficient in vivo click reactions. Specifically, we show that polymer modified tetrazines (PMT) are a key enabler for in vivo bioorthogonal chemistry based on the very fast and catalyst-free [4 + 2] tetrazine/trans-cyclooctene cycloaddition. Using fluorescent PMT for cellular resolution and 18F labeled PMT for whole animal imaging, we show that cancer cell epitopes can be easily reacted in vivo. This generic strategy should help guide the design of future chemistries and find widespread use for different in vivo bioorthogonal applications, particularly in the biomedical sciences. PMID:22411831

  20. Reactive polymer enables efficient in vivo bioorthogonal chemistry.

    PubMed

    Devaraj, Neal K; Thurber, Greg M; Keliher, Edmund J; Marinelli, Brett; Weissleder, Ralph

    2012-03-27

    There has been intense interest in the development of selective bioorthogonal reactions or "click" chemistry that can proceed in live animals. Until now however, most reactions still require vast surpluses of reactants because of steep temporal and spatial concentration gradients. Using computational modeling and design of pharmacokinetically optimized reactants, we have developed a predictable method for efficient in vivo click reactions. Specifically, we show that polymer modified tetrazines (PMT) are a key enabler for in vivo bioorthogonal chemistry based on the very fast and catalyst-free [4 + 2] tetrazine/trans-cyclooctene cycloaddition. Using fluorescent PMT for cellular resolution and (18)F labeled PMT for whole animal imaging, we show that cancer cell epitopes can be easily reacted in vivo. This generic strategy should help guide the design of future chemistries and find widespread use for different in vivo bioorthogonal applications, particularly in the biomedical sciences. PMID:22411831

  1. Temperature-dependent fluorescence lifetime of a fluorescent polymeric thermometer, poly(N-isopropylacrylamide), labeled by polarity and hydrogen bonding sensitive 4-sulfamoyl-7-aminobenzofurazan.

    PubMed

    Gota, Chie; Uchiyama, Seiichi; Yoshihara, Toshitada; Tobita, Seiji; Ohwada, Tomohiko

    2008-03-13

    Fluorescent molecular thermometers showing temperature-dependent fluorescence lifetimes enable thermal mapping of small spaces such as a microchannel and a living cell. We report the temperature-dependent fluorescence lifetimes of poly(NIPAM-co-DBD-AA), which is a random copolymer of N-isopropylacrylamide (NIPAM) and an environment-sensitive fluorescent monomer (DBD-AA) containing a 4-sulfamoyl-7-aminobenzofurazan structure. The average fluorescence lifetime of poly(NIPAM-co-DBD-AA) in aqueous solution increased from 4.22 to 14.1 ns with increasing temperature from 30 to 35 degrees C. This drastic change in fluorescence lifetime (27% increase per 1 degrees C) is the sharpest ever reported. Concentration independency, one of the advantages of fluorescence lifetime measurements, was seen in average fluorescence lifetime (13.7 +/- 0.18 ns) of poly(NIPAM-co-DBD-AA) at 33 degrees C over a wide concentration range (0.005-1 w/v%). With increasing temperature, polyNIPAM units in poly(NIPAM-co-DBD-AA) change their structure from an extended form to a globular form, providing apolar and aprotic environments to the fluorescent DBD-AA units. Consequently, the environment-sensitive DBD-AA units translate the local environmental changes into the extension of the fluorescence lifetime. This role of the DBD-AA units was revealed by a study of solvent effects on fluorescence lifetime of a model environment-sensitive fluorophore.

  2. Hyperspectral Fluorescence and Reflectance Imaging Instrument

    NASA Technical Reports Server (NTRS)

    Ryan, Robert E.; O'Neal, S. Duane; Lanoue, Mark; Russell, Jeffrey

    2008-01-01

    wavelength light-emitting-diode (LED) sources and white-light LED sources designed to produce consistently spatially stable light. White LEDs provide illumination for the measurement of reflectance spectra, while narrowband blue and UV LEDs are used to excite fluorescence. Each spectral type of LED can be turned on or off depending on the specific remote-sensing process being performed. Uniformity of illumination is achieved by using an array of LEDs and/or an integrating sphere or other diffusing surface. The image plane scanner uses a fore optic with a field of view large enough to provide an entire scan line on the image plane. It builds up a two-dimensional image in pushbroom fashion as the target is scanned across the image plane either by moving the object or moving the fore optic. For fluorescence detection, spectral filtering of a narrowband light illumination source is sometimes necessary to minimize the interference of the source spectrum wings with the fluorescence signal. Spectral filtering is achieved with optical interference filters and absorption glasses. This dual spectral imaging capability will enable the optimization of reflective, fluorescence, and fused datasets as well as a cost-effective design for multispectral imaging solutions. This system has been used in plant stress detection studies and in currency analysis.

  3. [Infrared fluorescent markers for microarray DNA analysis on biological microchip].

    PubMed

    Spitsyn, M A; Shershov, V E; Kuznetsova, V E; Barsky, V E; Egorov, E E; Emelyanova, M A; Kreindlin, E Ya; Lysov, Yu P; Guseinov, T O; Fesenko, D E; Lapa, S A; Surzhikov, S A; Abramov, I S; Nasedkina, T V; Zasedatelev, A S; Chudinov, A V

    2015-01-01

    To expand the informational capabilities of molecular genetic research, on the biological microchips, new indotricarbocyanine dyes that fluoresce in the near infrared (IR) spectral region have been synthesized. The developed IR dyes were studied using a biochip-based test system for detection of mutations in the BRCA1/BRCA2 and CHECK2 genes associated with breast cancer. The fluorescent label was introduced to the analyzed DNA during PCR using primers labeled with the synthesized IR dyes. An analyzer that allows recording and processing of images of fluorescent microarrays in the IR spectral region was designed and manufactured. It has been shown that the use of the synthesized dyes enables to conduct analysis in the IR region and improve the reliability of medical diagnostic tests due to low fluorescence intensity of sample components as well as of a biochip substrate and the reagents used for analysis. PMID:26510593

  4. Screening Fluorescent Voltage Indicators with Spontaneously Spiking HEK Cells

    PubMed Central

    Venkatachalam, Veena; Kralj, Joel M.; Dib-Hajj, Sulayman D.; Waxman, Stephen G.; Cohen, Adam E.

    2013-01-01

    Development of improved fluorescent voltage indicators is a key challenge in neuroscience, but progress has been hampered by the low throughput of patch-clamp characterization. We introduce a line of non-fluorescent HEK cells that stably express NaV 1.3 and KIR 2.1 and generate spontaneous electrical action potentials. These cells enable rapid, electrode-free screening of speed and sensitivity of voltage sensitive dyes or fluorescent proteins on a standard fluorescence microscope. We screened a small library of mutants of archaerhodopsin 3 (Arch) in spiking HEK cells and identified two mutants with greater voltage-sensitivity than found in previously published Arch voltage indicators. PMID:24391999

  5. Graphene as a Reversible and Spectrally Selective Fluorescence Quencher

    NASA Astrophysics Data System (ADS)

    Salihoglu, Omer; Kakenov, Nurbek; Balci, Osman; Balci, Sinan; Kocabas, Coskun

    2016-09-01

    We report reversible and spectrally selective fluorescence quenching of quantum dots (QDs) placed in close proximity to graphene. Controlling interband electronic transitions of graphene via electrostatic gating greatly modifies the fluorescence lifetime and intensity of nearby QDs via blocking of the nonradiative energy transfer between QDs and graphene. Using ionic liquid (IL) based electrolyte gating, we are able to control Fermi energy of graphene in the order of 1 eV, which yields electrically controllable fluorescence quenching of QDs in the visible spectrum. Indeed, our technique enables us to perform voltage controllable spectral selectivity among quantum dots at different emission wavelengths. We anticipate that our technique will provide tunable light-matter interaction and energy transfer that could yield hybrid QDs-graphene based optoelectronic devices with novel functionalities, and additionally, may be useful as a spectroscopic ruler, for example, in bioimaging and biomolecular sensing. We propose that graphene can be used as an electrically tunable and wavelength selective fluorescence quencher.

  6. Protein subcellular localization assays using split fluorescent proteins

    DOEpatents

    Waldo, Geoffrey S.; Cabantous, Stephanie

    2009-09-08

    The invention provides protein subcellular localization assays using split fluorescent protein systems. The assays are conducted in living cells, do not require fixation and washing steps inherent in existing immunostaining and related techniques, and permit rapid, non-invasive, direct visualization of protein localization in living cells. The split fluorescent protein systems used in the practice of the invention generally comprise two or more self-complementing fragments of a fluorescent protein, such as GFP, wherein one or more of the fragments correspond to one or more beta-strand microdomains and are used to "tag" proteins of interest, and a complementary "assay" fragment of the fluorescent protein. Either or both of the fragments may be functionalized with a subcellular targeting sequence enabling it to be expressed in or directed to a particular subcellular compartment (i.e., the nucleus).

  7. [Infrared fluorescent markers for microarray DNA analysis on biological microchip].

    PubMed

    Spitsyn, M A; Shershov, V E; Kuznetsova, V E; Barsky, V E; Egorov, E E; Emelyanova, M A; Kreindlin, E Ya; Lysov, Yu P; Guseinov, T O; Fesenko, D E; Lapa, S A; Surzhikov, S A; Abramov, I S; Nasedkina, T V; Zasedatelev, A S; Chudinov, A V

    2015-01-01

    To expand the informational capabilities of molecular genetic research, on the biological microchips, new indotricarbocyanine dyes that fluoresce in the near infrared (IR) spectral region have been synthesized. The developed IR dyes were studied using a biochip-based test system for detection of mutations in the BRCA1/BRCA2 and CHECK2 genes associated with breast cancer. The fluorescent label was introduced to the analyzed DNA during PCR using primers labeled with the synthesized IR dyes. An analyzer that allows recording and processing of images of fluorescent microarrays in the IR spectral region was designed and manufactured. It has been shown that the use of the synthesized dyes enables to conduct analysis in the IR region and improve the reliability of medical diagnostic tests due to low fluorescence intensity of sample components as well as of a biochip substrate and the reagents used for analysis.

  8. Fluorescence Experiments with Quinine

    ERIC Educational Resources Information Center

    O'Reilly, James E.

    1975-01-01

    Describes a series of experiments which illustrate the analytical capabilities of fluorescence, and outlines two straightforward analyses involving real analyses. These experiments are suitable for an undergraduate instrumental analysis course and require approximately six to seven hours of laboratory time. (MLH)

  9. Inducible fluorescent speckle microscopy.

    PubMed

    Pereira, António J; Aguiar, Paulo; Belsley, Michael; Maiato, Helder

    2016-01-18

    The understanding of cytoskeleton dynamics has benefited from the capacity to generate fluorescent fiducial marks on cytoskeleton components. Here we show that light-induced imprinting of three-dimensional (3D) fluorescent speckles significantly improves speckle signal and contrast relative to classic (random) fluorescent speckle microscopy. We predict theoretically that speckle imprinting using photobleaching is optimal when the laser energy and fluorophore responsivity are related by the golden ratio. This relation, which we confirm experimentally, translates into a 40% remaining signal after speckle imprinting and provides a rule of thumb in selecting the laser power required to optimally prepare the sample for imaging. This inducible speckle imaging (ISI) technique allows 3D speckle microscopy to be performed in readily available libraries of cell lines or primary tissues expressing fluorescent proteins and does not preclude conventional imaging before speckle imaging. As a proof of concept, we use ISI to measure metaphase spindle microtubule poleward flux in primary cells and explore a scaling relation connecting microtubule flux to metaphase duration. PMID:26783303

  10. Fluorescence and Light Scattering

    ERIC Educational Resources Information Center

    Clarke, Ronald J.; Oprysa, Anna

    2004-01-01

    The aim of the mentioned experiment is to aid students in developing tactics for distinguishing between signals originating from fluorescence and light scattering. Also, the experiment provides students with a deeper understanding of the physicochemical bases of each phenomenon and shows that the techniques are actually related.

  11. Ultraviolet fluorescence monitor

    SciTech Connect

    Hargis, P.J. Jr.; Preppernau, B.L.; Aragon, B.P.

    1997-05-01

    A multispectral ultraviolet (UV) fluorescence imaging fluorometer and a pulsed molecular beam laser fluorometer were developed to detect volatile organic compounds of interest in environmental monitoring and drug interdiction applications. The UV fluorescence imaging fluorometer is a relatively simple instrument which uses multiple excitation wavelengths to measure the excitation/emission matrix for irradiated samples. Detection limits in the high part-per-million to low part-per-million range were measured for a number of volatile organic vapors in the atmosphere. Detection limits in the low part-per-million range were obtained using cryogenic cooling to pre-concentrate unknown samples before introducing them into the imaging fluorometer. A multivariate analysis algorithm was developed to analyze the excitation/emission matrix and used to determine the relative concentrations of species in computer synthesized mixtures containing up to five organic compounds. Analysis results demonstrated the utility of multispectral UV fluorescence in analytical measurements. A transportable UV fluorescence imaging fluorometer was used in two field tests. Field test results demonstrated that detection limits in the part-per-billion range were needed to reliably identify volatile organic compounds in realistic field test measurements. The molecular beam laser fluorometer, a more complex instrument with detection limits in the part-per-billion to part-per-trillion range, was therefore developed to satisfy detection sensitivity requirements for field test measurements. High-resolution spectroscopic measurements made with the molecular beam laser fluorometer demonstrated its utility in identifying volatile organic compounds in the atmosphere.

  12. Fluorescent Gage Indication

    NASA Technical Reports Server (NTRS)

    Barns, C. E.; Gilbaugh, B. L.; Gin, B.; Holt, W. L.; Lesak, P.; Mancini, R.; Spencer, H. F.

    1985-01-01

    Transfer of dye shows quality of contact between two mating parts. Mating parts checked for fit by spreading fluorescent dye on one, making brief light contact with other, and looking (under UV light) for transferred dye. Dye offers greater visibility under ultraviolet illumination, allowing better indication of how precisely parts match and what areas interfere.

  13. Inducible fluorescent speckle microscopy

    PubMed Central

    Aguiar, Paulo; Belsley, Michael; Maiato, Helder

    2016-01-01

    The understanding of cytoskeleton dynamics has benefited from the capacity to generate fluorescent fiducial marks on cytoskeleton components. Here we show that light-induced imprinting of three-dimensional (3D) fluorescent speckles significantly improves speckle signal and contrast relative to classic (random) fluorescent speckle microscopy. We predict theoretically that speckle imprinting using photobleaching is optimal when the laser energy and fluorophore responsivity are related by the golden ratio. This relation, which we confirm experimentally, translates into a 40% remaining signal after speckle imprinting and provides a rule of thumb in selecting the laser power required to optimally prepare the sample for imaging. This inducible speckle imaging (ISI) technique allows 3D speckle microscopy to be performed in readily available libraries of cell lines or primary tissues expressing fluorescent proteins and does not preclude conventional imaging before speckle imaging. As a proof of concept, we use ISI to measure metaphase spindle microtubule poleward flux in primary cells and explore a scaling relation connecting microtubule flux to metaphase duration. PMID:26783303

  14. Inkjet printed fluorescent nanorod layers exhibit superior optical performance over quantum dots.

    PubMed

    Halivni, Shira; Shemesh, Shay; Waiskopf, Nir; Vinetsky, Yelena; Magdassi, Shlomo; Banin, Uri

    2015-12-01

    Semiconductor nanocrystals exhibit unique fluorescence properties which are tunable in size, shape and composition. The high quantum yield and enhanced stability have led to their use in biomedical imaging and flat panel displays. Here, semiconductor nanorod based inkjet inks are presented, overcoming limitations of the commonly reported quantum dots in printing applications. Fluorescent seeded nanorods were found to be outstanding candidates for fluorescent inks, due to their low particle-particle interactions and negligible self-absorption. This is manifested by insignificant emission shifts upon printing, even in highly concentrated printed layers and by maintenance of a high fluorescence quantum yield, unlike quantum dots which exhibit fluorescence wavelength shifts and quenching effects. This behavior results from the reduced absorption/emission overlap, accompanied by low energy transfer efficiencies between the nanorods as supported by steady state and time resolved fluorescence measurements. The new seeded nanorod inks enable patterning of thin fluorescent layers, for demanding light emission applications such as signage and displays.

  15. Bimolecular fluorescence complementation.

    PubMed

    Wong, Katy A; O'Bryan, John P

    2011-01-01

    Defining the subcellular distribution of signaling complexes is imperative to understanding the output from that complex. Conventional methods such as immunoprecipitation do not provide information on the spatial localization of complexes. In contrast, BiFC monitors the interaction and subcellular compartmentalization of protein complexes. In this method, a fluororescent protein is split into amino- and carboxy-terminal non-fluorescent fragments which are then fused to two proteins of interest. Interaction of the proteins results in reconstitution of the fluorophore (Figure 1). A limitation of BiFC is that once the fragmented fluorophore is reconstituted the complex is irreversible. This limitation is advantageous in detecting transient or weak interactions, but precludes a kinetic analysis of complex dynamics. An additional caveat is that the reconstituted flourophore requires 30min to mature and fluoresce, again precluding the observation of real time interactions. BiFC is a specific example of the protein fragment complementation assay (PCA) which employs reporter proteins such as green fluorescent protein variants (BiFC), dihydrofolate reductase, b-lactamase, and luciferase to measure protein:protein interactions. Alternative methods to study protein:protein interactions in cells include fluorescence co-localization and Förster resonance energy transfer (FRET). For co-localization, two proteins are individually tagged either directly with a fluorophore or by indirect immunofluorescence. However, this approach leads to high background of non-interacting proteins making it difficult to interpret co-localization data. In addition, due to the limits of resolution of confocal microscopy, two proteins may appear co-localized without necessarily interacting. With BiFC, fluorescence is only observed when the two proteins of interest interact. FRET is another excellent method for studying protein:protein interactions, but can be technically challenging. FRET

  16. Noncovalent functionalization of carbon nanotubes by fluorescent polypeptides: supramolecular conjugates with pH-dependent absorbance and fluorescence.

    PubMed

    Huang, Xin Hua; Johnson, Renjith P; Song, Song I; Kim, Il

    2013-11-01

    Fluorescent cut single-walled carbon nanotube (CSWCNT) were prepared by simply mixing CSWCNT with water soluble rhodamine 6G (Rh6G) conjugated poly(3,4-dihydroxyphenylalanine) and poly(L-tyrosine) to form highly stable product with good dispersity in buffer solution. The optical absorbance and fluorescence spectra of the resulting fluorescent CSWCNT display interesting pH-dependent optical properties, emitting strong fluorescence only in acidic environment. Considering the extracellular pH of tumor tissue is acidic, the pH-sensitive conjugates have advantages to sense tumor cells selectively, enabling it to be utilized as a biosensor for detecting cancer cells. The protocol employed to functionalize the CSWCNT with Rh6G conjugated polypeptides in aqueous solution is proven to be direct, fast and easily scalable. PMID:24245264

  17. Simultaneous neuron- and astrocyte-specific fluorescent marking

    SciTech Connect

    Schulze, Wiebke; Hayata-Takano, Atsuko; Kamo, Toshihiko; Nakazawa, Takanobu; Nagayasu, Kazuki; Kasai, Atsushi; Seiriki, Kaoru; Shintani, Norihito; Ago, Yukio; Farfan, Camille; and others

    2015-03-27

    Systematic and simultaneous analysis of multiple cell types in the brain is becoming important, but such tools have not yet been adequately developed. Here, we aimed to generate a method for the specific fluorescent labeling of neurons and astrocytes, two major cell types in the brain, and we have developed lentiviral vectors to express the red fluorescent protein tdTomato in neurons and the enhanced green fluorescent protein (EGFP) in astrocytes. Importantly, both fluorescent proteins are fused to histone 2B protein (H2B) to confer nuclear localization to distinguish between single cells. We also constructed several expression constructs, including a tandem alignment of the neuron- and astrocyte-expression cassettes for simultaneous labeling. Introducing these vectors and constructs in vitro and in vivo resulted in cell type-specific and nuclear-localized fluorescence signals enabling easy detection and distinguishability of neurons and astrocytes. This tool is expected to be utilized for the simultaneous analysis of changes in neurons and astrocytes in healthy and diseased brains. - Highlights: • We develop a method for the specific fluorescent labeling of neurons and astrocytes. • Neuron-specific labeling is achieved using Scg10 and synapsin promoters. • Astrocyte-specific labeling is generated using the minimal GFAP promoter. • Nuclear localization of fluorescent proteins is achieved with histone 2B protein.

  18. Fluorescence Microscopy of Single Molecules

    ERIC Educational Resources Information Center

    Zimmermann, Jan; van Dorp, Arthur; Renn, Alois

    2004-01-01

    The investigation of photochemistry and photophysics of individual quantum systems is described with the help of a wide-field fluorescence microscopy approach. The fluorescence single molecules are observed in real time.

  19. Preclinical evaluation of near-infrared (NIR) fluorescently labeled cetuximab as a potential tool for fluorescence-guided surgery.

    PubMed

    Saccomano, Mara; Dullin, Christian; Alves, Frauke; Napp, Joanna

    2016-11-15

    The high rate of recurrence in patients with pancreatic ductal adenocarcinoma (PDAC) could be reduced by supporting the surgeons in discriminating healthy from diseased tissues with intraoperative fluorescence-guidance. Here, we studied the suitability of Cetuximab, a therapeutic monoclonal antibody targeting the human epidermal growth factor receptor (EGFR), near-infrared (NIR) fluorescently labeled as a new tool for fluorescence-guided surgery. Distribution and binding of systemically injected Cetuximab Alexa Fluor 647 conjugate (Cetux-Alexa-647) and the co-injected control human IgG Alexa Fluor 750 conjugate (hIgG-Alexa-750) was studied over 48 h by NIR fluorescence imaging in mice bearing human orthotopic AsPC-1 and MIA PaCa-2 PDAC tumors. Cetux-Alexa-647, but not the control hIgG-Alexa-750 fluorescence, was specifically detected in vivo in both primary pancreatic tumors with maximum fluorescence intensities at 24 h, and in metastases of AsPC-1 tumors as small as 1 mm. Lifetime analysis and NIR fluorescence microscopy of tumor sections confirmed the binding specificity of Cetux-Alexa-647 to PDAC cells. Comparable results were obtained with Cetuximab conjugated to Alexa Fluor 750 dye (Cetux-Alexa-750). Fluorescence-guided dissection, performed 24 h after injection of Cetuximab conjugated to IRDye 800CW (Cetux-800CW), enabled a real-time delineation of AsPC-1 tumor margins, and small metastases. Odyssey scans revealed that only the vital part of the tumor, but not the necrotic part was stained with Cetux-800CW. NIR fluorescently labeled Cetuximab may be a promising tool that can be applied for fluorescence-guided surgery to visualize tumor margins and metastatic sites in order to allow a precise surgical resection. PMID:27428782

  20. Preclinical evaluation of near-infrared (NIR) fluorescently labeled cetuximab as a potential tool for fluorescence-guided surgery.

    PubMed

    Saccomano, Mara; Dullin, Christian; Alves, Frauke; Napp, Joanna

    2016-11-15

    The high rate of recurrence in patients with pancreatic ductal adenocarcinoma (PDAC) could be reduced by supporting the surgeons in discriminating healthy from diseased tissues with intraoperative fluorescence-guidance. Here, we studied the suitability of Cetuximab, a therapeutic monoclonal antibody targeting the human epidermal growth factor receptor (EGFR), near-infrared (NIR) fluorescently labeled as a new tool for fluorescence-guided surgery. Distribution and binding of systemically injected Cetuximab Alexa Fluor 647 conjugate (Cetux-Alexa-647) and the co-injected control human IgG Alexa Fluor 750 conjugate (hIgG-Alexa-750) was studied over 48 h by NIR fluorescence imaging in mice bearing human orthotopic AsPC-1 and MIA PaCa-2 PDAC tumors. Cetux-Alexa-647, but not the control hIgG-Alexa-750 fluorescence, was specifically detected in vivo in both primary pancreatic tumors with maximum fluorescence intensities at 24 h, and in metastases of AsPC-1 tumors as small as 1 mm. Lifetime analysis and NIR fluorescence microscopy of tumor sections confirmed the binding specificity of Cetux-Alexa-647 to PDAC cells. Comparable results were obtained with Cetuximab conjugated to Alexa Fluor 750 dye (Cetux-Alexa-750). Fluorescence-guided dissection, performed 24 h after injection of Cetuximab conjugated to IRDye 800CW (Cetux-800CW), enabled a real-time delineation of AsPC-1 tumor margins, and small metastases. Odyssey scans revealed that only the vital part of the tumor, but not the necrotic part was stained with Cetux-800CW. NIR fluorescently labeled Cetuximab may be a promising tool that can be applied for fluorescence-guided surgery to visualize tumor margins and metastatic sites in order to allow a precise surgical resection.

  1. Virtual Hematoxylin and Eosin Transillumination Microscopy Using Epi-Fluorescence Imaging

    PubMed Central

    Husvogt, Lennart; Vardeh, Hilde; Faulkner-Jones, Beverly E.; Hornegger, Joachim; Connolly, James L.; Fujimoto, James G.

    2016-01-01

    We derive a physically realistic model for the generation of virtual transillumination, white light microscopy images using epi-fluorescence measurements from thick, unsectioned tissue. We demonstrate this technique by generating virtual transillumination H&E images of unsectioned human breast tissue from epi-fluorescence multiphoton microscopy data. The virtual transillumination algorithm is shown to enable improved contrast and color accuracy compared with previous color mapping methods. Finally, we present an open source implementation of the algorithm in OpenGL, enabling real-time GPU-based generation of virtual transillumination microscopy images using conventional fluorescence microscopy systems. PMID:27500636

  2. Three-dimensional tracking of a single fluorescent nanoparticle using four-focus excitation in a confocal microscope.

    PubMed

    Germann, James A; Davis, Lloyd M

    2014-03-10

    We report high sensitivity detection and tracking of a single fluorescent nanoparticle in solution by use of four alternately pulsed laser diodes for fluorescence excitation in a confocal microscope. Slight offsets between the centers of the overlapping laser foci together with time-resolved photon counting enable sub-micron precision position measurements. Real-time correction for diffusional motion with a xyz-piezo stage then enables tracking of a nanoparticle with diffusivity up to ~12 μm(2) s(-1). Fluorescence correlation spectroscopy and calibration measurements indicate a net fluorescence photon detection efficiency of ~6-9%, comparable to that of an optimized single-molecule microscope. PMID:24663905

  3. Fluorescent noble metal nanoclusters

    NASA Astrophysics Data System (ADS)

    Zheng, Jie

    Water-soluble fluorescent metallic clusters at sizes comparable to the Fermi wavelength of an electron (˜0.5 nm for gold and silver) were created and their photophysical properties were investigated at the bulk and single molecule levels. We employed biocompatible dendrimer and peptide to prepare a series of strong fluorescent gold and silver clusters with chemical or photo reduction methods. Facilitated by the well-defined dendrimer size, electrospray ionization mass spectrometry indicates that the fluorescent silver nanocluster size ranges from 2 to 8 Ag atoms. The correlation of emission energy with the number of atoms, N, in each gold nanocluster is quantitatively fit for the smallest nanoclusters with no adjustable parameters by the simple scaling relation of EFermi/N1/3, in which EFermi is the Fermi energy of bulk gold. The transition energy scaling inversely with cluster radius indicates that electronic structure can be well described with the spherical jellium model and further demonstrates that these nanomaterials are "multi-electron artificial atoms". Fluorescence from these small metal clusters can be considered protoplasmonic, molecular transitions of the free conduction electrons before the onset of collective dipole oscillations occurring when a continuous density of states is reached. In addition, very strong single molecular Stokes and anti-Stokes Raman enhancement by fluorescent silver clusters was observed. Pushing to larger sizes, we also created ˜2nm diameter glutathione encapsulated luminescent gold nanoparticles. Distinct from similarly sized but nonluminescent gold nanoparticles, these 2 nm gold nanoparticles show bright, long lifetime emission but no plasmon absorption. The emission might arise from charge transfer between gold atoms and the thiol ligand. Providing the "missing link" between atomic and nanoparticle behavior in noble metals, these highly fluorescent, water-soluble gold and silver nanoclusters offer complementary transition

  4. Global analysis of fluorescence decays to probe the internal dynamics of fluorescently labeled macromolecules.

    PubMed

    Duhamel, Jean

    2014-03-11

    The aim of this review is to introduce the reader first to the mathematical complexity associated with the analysis of fluorescence decays acquired with solutions of macromolecules labeled with a fluorophore and its quencher that are capable of interacting with each other via photophysical processes within the macromolecular volume, second to the experimental and mathematical approaches that have been proposed over the years to handle this mathematical complexity, and third to the information that one can expect to retrieve with respect to the internal dynamics of such fluorescently labeled macromolecules. In my view, the ideal fluorophore-quencher pair to use in studying the internal dynamics of fluorescently labeled macromolecules would involve a long-lived fluorophore, a fluorophore and a quencher that do not undergo energy migration, and a photophysical process that results in a change in fluorophore emission upon contact between the excited fluorophore and quencher. Pyrene, with its ability to form an excimer on contact between excited-state and ground-state species, happens to possess all of these properties. Although the concepts described in this review apply to any fluorophore and quencher pair sharing pyrene's exceptional photophysical properties, this review focuses on the study of pyrene-labeled macromolecules that have been characterized in great detail over the past 40 years and presents the main models that are being used today to analyze the fluorescence decays of pyrene-labeled macromolecules reliably. These models are based on Birks' scheme, the DMD model, the fluorescence blob model, and the model free analysis. The review also provides a step-by-step protocol that should enable the noneducated user to achieve a successful decay analysis exempt of artifacts. Finally, some examples of studies of pyrene-labeled macromolecules are also presented to illustrate the different types of information that can be retrieved from these fluorescence decay

  5. Quantum Dot Enabled Molecular Sensing and Diagnostics

    PubMed Central

    Zhang, Yi; Wang, Tza-Huei

    2012-01-01

    Since its emergence, semiconductor nanoparticles known as quantum dots (QDs) have drawn considerable attention and have quickly extended their applicability to numerous fields within the life sciences. This is largely due to their unique optical properties such as high brightness and narrow emission band as well as other advantages over traditional organic fluorophores. New molecular sensing strategies based on QDs have been developed in pursuit of high sensitivity, high throughput, and multiplexing capabilities. For traditional biological applications, QDs have already begun to replace traditional organic fluorophores to serve as simple fluorescent reporters in immunoassays, microarrays, fluorescent imaging applications, and other assay platforms. In addition, smarter, more advanced QD probes such as quantum dot fluorescence resonance energy transfer (QD-FRET) sensors, quenching sensors, and barcoding systems are paving the way for highly-sensitive genetic and epigenetic detection of diseases, multiplexed identification of infectious pathogens, and tracking of intracellular drug and gene delivery. When combined with microfluidics and confocal fluorescence spectroscopy, the detection limit is further enhanced to single molecule level. Recently, investigations have revealed that QDs participate in series of new phenomena and exhibit interesting non-photoluminescent properties. Some of these new findings are now being incorporated into novel assays for gene copy number variation (CNV) studies and DNA methylation analysis with improved quantification resolution. Herein, we provide a comprehensive review on the latest developments of QD based molecular diagnostic platforms in which QD plays a versatile and essential role. PMID:22916072

  6. Electronic Health Record Application Support Service Enablers.

    PubMed

    Neofytou, M S; Neokleous, K; Aristodemou, A; Constantinou, I; Antoniou, Z; Schiza, E C; Pattichis, C S; Schizas, C N

    2015-08-01

    There is a huge need for open source software solutions in the healthcare domain, given the flexibility, interoperability and resource savings characteristics they offer. In this context, this paper presents the development of three open source libraries - Specific Enablers (SEs) for eHealth applications that were developed under the European project titled "Future Internet Social and Technological Alignment Research" (FI-STAR) funded under the "Future Internet Public Private Partnership" (FI-PPP) program. The three SEs developed under the Electronic Health Record Application Support Service Enablers (EHR-EN) correspond to: a) an Electronic Health Record enabler (EHR SE), b) a patient summary enabler based on the EU project "European patient Summary Open Source services" (epSOS SE) supporting patient mobility and the offering of interoperable services, and c) a Picture Archiving and Communications System (PACS) enabler (PACS SE) based on the dcm4che open source system for the support of medical imaging functionality. The EHR SE follows the HL7 Clinical Document Architecture (CDA) V2.0 and supports the Integrating the Healthcare Enterprise (IHE) profiles (recently awarded in Connectathon 2015). These three FI-STAR platform enablers are designed to facilitate the deployment of innovative applications and value added services in the health care sector. They can be downloaded from the FI-STAR cataloque website. Work in progress focuses in the validation and evaluation scenarios for the proving and demonstration of the usability, applicability and adaptability of the proposed enablers. PMID:26736531

  7. A synthesis of fluorescent starch based on carbon nanoparticles for fingerprints detection

    NASA Astrophysics Data System (ADS)

    Li, Hongren; Guo, Xingjia; Liu, Jun; Li, Feng

    2016-10-01

    A pyrolysis method for synthesizing carbon nanoparticles (CNPs) were developed by using malic acid and ammonium oxalate as raw materials. The incorporation of a minor amount of carbon nanoparticles into starch powder imparts remarkable color-tunability. Based on this phenomenon, an environment friendly fluorescent starch powder for detecting latent fingerprints in non-porous surfaces was prepared. The fingerprints on different non-porous surfaces developed with this powder showed very good fluorescent images under ultraviolet excitation. The method using fluorescent starch powder as fluorescent marks is simple, rapid and green. Experimental results illustrated the effectiveness of proposed methods, enabling its practical applications in forensic sciences.

  8. Magnetic fluorescent lamp

    DOEpatents

    Berman, S.M.; Richardson R.W.

    1983-12-29

    The radiant emission of a mercury-argon discharge in a fluorescent lamp assembly is enhanced by providing means for establishing a magnetic field with lines of force along the path of electron flow through the bulb of the lamp assembly, to provide Zeeman splitting of the ultraviolet spectral line. Optimum results are obtained when the magnetic field strength causes a Zeeman splitting of approximately 1.7 times the thermal line width.

  9. Near-infrared hyperspectral microscopy of carbon nanotube photoluminescence enables 17-color imaging (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Heller, Daniel A.; Roxbury, Daniel; Jena, Prakrit V.; Williams, Ryan M.; Enyedi, Balázs; Niethammer, Philipp; Marcet, Stéphane; Mangiarini, Francesca; Verhaegen, Marc; Blais-Ouellette, Sébastien

    2016-03-01

    The intrinsic near-infrared photoluminescence (fluorescence) of single-walled carbon nanotubes exhibits unique photostability, narrow bandwidth, penetration through biological media, environmental sensitivity, and both chromatic variety and range. Biomedical applications exploiting this large family of fluorophores will require the spectral and spatial resolution of individual (n,m) nanotube species' fluorescence and its modulation within live cells and tissues, which is not possible with current microscopy methods. We present a wide-field hyperspectral approach to spatially delineate and spectroscopically measure single nanotube fluorescence in living systems. This approach resolved up to 17 distinct (n,m) species (chiralities) with single nanotube spatial resolution in live mammalian cells, murine tissues ex vivo, and zebrafish endothelium in vivo. We anticipate that this approach will facilitate multiplexed nanotube imaging in biomedical applications while enabling deep-tissue optical penetration, exceptional photostability, and single-molecule resolution in vivo.

  10. Fluorescent imaging of cancerous tissues for targeted surgery

    PubMed Central

    Bu, Lihong; Shen, Baozhong; Cheng, Zhen

    2014-01-01

    To maximize tumor excision and minimize collateral damage is the primary goal of cancer surgery. Emerging molecular imaging techniques have to “image-guided surgery” developing into “molecular imaging-guided surgery”, which is termed “targeted surgery” in this review. Consequently, the precision of surgery can be advanced from tissue-scale to molecule-scale, enabling “targeted surgery” to be a component of “targeted therapy”. Evidence from numerous experimental and clinical studies has demonstrated significant benefits of fluorescent imaging in targeted surgery with preoperative molecular diagnostic screening. Fluorescent imaging can help to improve intraoperative staging and enable more radical cytoreduction, detect obscure tumor lesions in special organs, highlight tumor margins, better map lymph node metastases, and identify important normal structures intraoperatively. Though limited tissue penetration of fluorescent imaging and tumor heterogeneity are two major hurdles for current targeted surgery, multimodality imaging and multiplex imaging may provide potential solutions to overcome these issues, respectively. Moreover, though many fluorescent imaging techniques and probes have been investigated, targeted surgery remains at a proof-of-principle stage. The impact of fluorescent imaging on cancer surgery will likely be realized through persistent interdisciplinary amalgamation of research in diverse fields. PMID:25064553

  11. Confocal fluorescence microendoscopy of bronchial epithelium

    NASA Astrophysics Data System (ADS)

    Lane, Pierre M.; Lam, Stephen; McWilliams, Annette; Leriche, Jean C.; Anderson, Marshall W.; Macaulay, Calum E.

    2009-03-01

    Confocal microendoscopy permits the acquisition of high-resolution real-time confocal images of bronchial mucosa via the instrument channel of an endoscope. We report here on the construction and validation of a confocal fluorescence microendoscope and its use to acquire images of bronchial epithelium in vivo. Our objective is to develop an imaging method that can distinguish preneoplastic lesions from normal epithelium to enable us to study the natural history of these lesions and the efficacy of chemopreventive agents without biopsy removal of the lesion that can introduce a spontaneous regression bias. The instrument employs a laser-scanning engine and bronchoscope-compatible confocal probe consisting of a fiber-optic image guide and a graded-index objective lens. We assessed the potential of topical application of physiological pH cresyl violet (CV) as a fluorescence contrast-enhancing agent for the visualization of tissue morphology. Images acquired ex vivo with the confocal microendoscope were first compared with a bench-top confocal fluorescence microscope and conventional histology. Confocal images from five sites topically stained with CV were then acquired in vivo from high-risk smokers and compared to hematoxylin and eosin stained sections of biopsies taken from the same site. Sufficient contrast in the confocal imagery was obtained to identify cells in the bronchial epithelium. However, further improvements in the miniature objective lens are required to provide sufficient axial resolution for accurate classification of preneoplastic lesions.

  12. Integrated fluorescence and transmission electron microscopy.

    PubMed

    Agronskaia, Alexandra V; Valentijn, Jack A; van Driel, Linda F; Schneijdenberg, Chris T W M; Humbel, Bruno M; van Bergen en Henegouwen, Paul M P; Verkleij, Arie J; Koster, Abraham J; Gerritsen, Hans C

    2008-11-01

    Correlative microscopy is a powerful technique that combines the strengths of fluorescence microscopy and electron microscopy. The first enables rapid searching for regions of interest in large fields of view while the latter exhibits superior resolution over a narrow field of view. Routine use of correlative microscopy is seriously hampered by the cumbersome and elaborate experimental procedures. This is partly due to the use of two separate microscopes for fluorescence and electron microscopy. Here, an integrated approach to correlative microscopy is presented based on a laser scanning fluorescence microscope integrated in a transmission electron microscope. Using this approach the search for features in the specimen is greatly simplified and the time to carry out the experiment is strongly reduced. The potential of the integrated approach is demonstrated at room temperature on specimens of rat intestine cells labeled with AlexaFluor488 conjugated to wheat germ agglutinin and on rat liver peroxisomes immunolabeled with anti-catalase antibodies and secondary AlexaFluor488 antibodies and 10nm protein A-gold.

  13. Silent, fluorescent labeling of native neuronal receptors.

    PubMed

    Vytla, Devaiah; Combs-Bachmann, Rosamund E; Hussey, Amanda M; Hafez, Ismail; Chambers, James J

    2011-10-21

    We have developed a minimally-perturbing strategy that enables labeling and subcellular visualization of endogenous dendritic receptors on live, wild-type neurons. Specifically, calcium-permeable non-NMDA glutamate receptors expressed in hippocampal neurons can be targeted with this novel synthetic tri-functional molecule. This ligand-directed probe was targeted towards AMPA receptors and bears an electrophilic group for covalent bond formation with an amino acid side chain on the extracellular side of the ion channel. This molecule was designed in such a way that the use-dependent, polyamine-based ligand accumulates the chemically-reactive group at the extracellular side of these polyamine-sensitive receptors, thereby allowing covalent bond formation between an electrophilic moiety on the nanoprobe and a nucleophilic amino acid sidechain on the receptor. Bioconjugation of this molecule results in a stable covalent bond between the nanoprobe and the target receptor. Subsequent photolysis of a portion of the nanoprobe may then be employed to effect ligand release allowing the receptor to re-enter the non-liganded state, all the while retaining the fluorescent beacon for visualization. This technology allows for rapid fluorescent labeling of native polyamine-sensitive receptors and further advances the field of fluorescent labeling of native biological molecules.

  14. Molecular cytogenetics using fluorescence in situ hybridization

    SciTech Connect

    Gray, J.W.; Kuo, Wen-Lin; Lucas, J.; Pinkel, D.; Weier, H-U.; Yu, Loh-Chung.

    1990-12-07

    Fluorescence in situ hybridization (FISH) with chromosome-specific probes enables several new areas of cytogenetic investigation by allowing visual determination of the presence and normality of specific genetic sequences in single metaphase or interphase cells. in this approach, termed molecular cytogenetics, the genetic loci to be analyzed are made microscopically visible in single cells using in situ hybridization with nucleic acid probes specific to these loci. To accomplish this, the DNA in the target cells is made single stranded by thermal denaturation and incubated with single-stranded, chemically modified probe under conditions where the probe will anneal only with DNA sequences to which it has high DNA sequence homology. The bound probe is then made visible by treatment with a fluorescent reagent such as fluorescein that binds to the chemical modification carried by the probe. The DNA to which the probe does not bind is made visible by staining with a dye such as propidium iodide that fluoresces at a wavelength different from that of the reagent used for probe visualization. We show in this report that probes are now available that make this technique useful for biological dosimetry, prenatal diagnosis and cancer biology. 31 refs., 3 figs.

  15. Surface plasmon enhanced-field fluorescence biosensor for point-of-care testing using fluorescent nanoparticles

    NASA Astrophysics Data System (ADS)

    Horii, Kazuyoshi; Kimura, Toshihito; Ohtsuka, Hisashi; Kasagi, Noriyuki; Oohara, Tomoya; Matsuno, Tadahiro; Hakamata, Masashi; Komatsu, Akihiro; Sendai, Tomonari

    2012-03-01

    An optical biosensor system using surface-plasmon field-enhanced fluorescence has been developed, which allows high sensitivity and fast measurement available. Intensity of fluorophores in SPFS is highly dependent upon the distance from metal surface. The resonant evanescent electric field excites fluorophores within the penetration area. On the other hand, fluorescence quenching in close proximity to a metal surface interfere with the excitation. We have developed a new technology for fluorescent nanoparticles that could receive the energy from metal surface effectively. This enables technology of detecting strong and stable SPFS signals, as well as homogeneous assay method that allows us to eliminate binding/free separation process for unreacted fluorescent particles. A rate assay method has also been employed, which resolves affect from diffusion-limited access, in order to realize a fast surface immunoreaction in a microchannel. Taking advantage of these two developments, as eliminating an enzyme response process such as CLEIA, our system reaches much faster reaction time of 2 minutes to detect thyroid stimulating hormone (TSH) of canine serum sample at 0.1ng/mL. We believe our system with these new technologies is a powerful tool for in-vitro diagnosis which meets various clinical requirements.

  16. Optically Modulated Fluorescence Bioimaging: Visualizing Obscured Fluorophores in High Background

    PubMed Central

    2015-01-01

    Conspectus Fluorescence microscopy and detection have become indispensible for understanding organization and dynamics in biological systems. Novel fluorophores with improved brightness, photostability, and biocompatibility continue to fuel further advances but often rely on having minimal background. The visualization of interactions in very high biological background, especially for proteins or bound complexes at very low copy numbers, remains a primary challenge. Instead of focusing on molecular brightness of fluorophores, we have adapted the principles of high-sensitivity absorption spectroscopy to improve the sensitivity and signal discrimination in fluorescence bioimaging. Utilizing very long wavelength transient absorptions of kinetically trapped dark states, we employ molecular modulation schemes that do not simultaneously modulate the background fluorescence. This improves the sensitivity and ease of implementation over high-energy photoswitch-based recovery schemes, as no internal dye reference or nanoparticle-based fluorophores are needed to separate the desired signals from background. In this Account, we describe the selection process for and identification of fluorophores that enable optically modulated fluorescence to decrease obscuring background. Differing from thermally stable photoswitches using higher-energy secondary lasers, coillumination at very low energies depopulates transient dark states, dynamically altering the fluorescence and giving characteristic modulation time scales for each modulatable emitter. This process is termed synchronously amplified fluorescence image recovery (SAFIRe) microscopy. By understanding and optically controlling the dye photophysics, we selectively modulate desired fluorophore signals independent of all autofluorescent background. This shifts the fluorescence of interest to unique detection frequencies with nearly shot-noise-limited detection, as no background signals are collected. Although the fluorescence

  17. Imaging cellular dynamics in vivo with multicolor fluorescent proteins

    NASA Astrophysics Data System (ADS)

    Hoffman, Robert M.

    2005-04-01

    The new field of in vivo cell biology is being developed with multi-colored fluorescent proteins. With the use of fluorescent proteins, the behavior of individual cells can be visualized in the living animal. An example of the new cell biology is dual-color fluorescence imaging using red fluorescent protein (RFP)-expressing tumors transplanted in green fluorescent protein (GFP)-expressing transgenic mice. These models show with great clarity the details of the tumor-stroma cell-cell interaction especially tumor-induced angiogenesis, tumor-infiltrating lymphocytes, stromal fibroblasts and macrophages. Another example is the color-coding of cells with RFP or GFP such that both cell types and their interaction can be simultaneously visualized in vivo. Stem cells can also be visualized and tracked in vivo with fluorescent proteins. Mice, in which the regulatory elements of the stem-cell marker nestin drive GFP expression, can be used to visualize hair follicle stem cells including their ability to form hair follicles as well as blood vessels. Dual-color cells expressing GFP in the nucleus and RFP in the cytoplasm enable real-time visualization of nuclear-cytoplasm dynamics including cell cycle events and apoptosis. Dual-color cells also enable the in vivo imaging of cell and nuclear deformation as well as trafficking in capillaries in living animals. Multiple-color labeling of cells will enable multiple events to be simultaneously visualized in vivo including cell-cell interaction, gene expression, ion fluxes, protein and organelle trafficking, chromosome dynamics and numerous other processes currently still studied in vitro.

  18. Time-resolved fluorescence microscopy.

    PubMed

    Suhling, Klaus; French, Paul M W; Phillips, David

    2005-01-01

    In fluorescence microscopy, the fluorescence emission can be characterised not only by intensity and position, but also by lifetime, polarization and wavelength. Fluorescence lifetime imaging (FLIM) can report on photophysical events that are difficult or impossible to observe by fluorescence intensity imaging, and time-resolved fluorescence anisotropy imaging (TR-FAIM) can measure the rotational mobility of a fluorophore in its environment. We compare different FLIM methods: a chief advantage of wide-field time-gating and phase modulation methods is the speed of acquisition whereas for time-correlated single photon counting (TCSPC) based confocal scanning it is accuracy in the fluorescence decay. FLIM has been used to image interactions between proteins such as receptor oligomerisation and to reveal protein phosphorylation by detecting fluorescence resonance energy transfer (FRET). In addition, FLIM can also probe the local environment of fluorophores, reporting, for example, on the local pH, refractive index, ion or oxygen concentration without the need for ratiometric measurements.

  19. Fluorescent ligands for adenosine receptors.

    PubMed

    Kozma, Eszter; Jayasekara, P Suresh; Squarcialupi, Lucia; Paoletta, Silvia; Moro, Stefano; Federico, Stephanie; Spalluto, Giampiero; Jacobson, Kenneth A

    2013-01-01

    Interest is increasing in developing fluorescent ligands for characterization of adenosine receptors (ARs), which hold a promise of usefulness in the drug discovery process. The size of a strategically labeled AR ligand can be greatly increased after the attachment of a fluorophore. The choice of dye moiety (e.g. Alexa Fluor 488), attachment point and linker length can alter the selectivity and potency of the parent molecule. Fluorescent derivatives of adenosine agonists and antagonists (e.g. XAC and other heterocyclic antagonist scaffolds) have been synthesized and characterized pharmacologically. Some are useful AR probes for flow cytometry, fluorescence correlation spectroscopy, fluorescence microscopy, fluorescence polarization, fluorescence resonance energy transfer, and scanning confocal microscopy. Thus, the approach of fluorescent labeled GPCR ligands, including those for ARs, is a growing dynamic research field.

  20. Fluorescence photodiagnosis in clinical practice.

    PubMed

    Moghissi, K; Stringer, M R; Dixon, Kate

    2008-12-01

    Fluorescence diagnosis has become an important method of investigation in clinical practice particularly in identification and localisation of pre and early cancerous lesions as well as image guided therapy. The method relies on the principle of differential fluorescence emission between abnormal and normal tissues in response to excitation by a specific wavelength of light within the visible spectrum range. In clinical practice two types of fluorescence diagnostic methods are used, namely autofluorescence and drug-induced fluorescence. The former relies on the differential fluorescence of "native" fluorophores whereas the latter requires a photosensitiser which enhances the differential fluorescence emission of the normal versus the abnormal tissues. Development and advances in fibreoptic, endoscopic instrumentation currently permit fluorescence endoscopy to be carried out in a number of situations. PMID:19356662

  1. Photodynamic tumor therapy and on-line fluorescence spectroscopy after ALA administration using 633-nm light as therapeutic and fluorescence excitation radiation

    NASA Astrophysics Data System (ADS)

    Koenig, Karsten; Kienle, Alwin; Boehncke, Wolf-Henning; Kaufmann, Roland; Rueck, Angelika C.; Meier, Thomas H.; Steiner, Rudolf W.

    1994-09-01

    Photodynamic therapy (PDT) and on-line fluorescence spectroscopy were carried out on human tumors after 5-aminolevulinic acid (ALA) administration using 633-nm light of a dye laser as therapeutic radiation and as fluorescence excitation radiation. This has the advantages of (1) enabling use of one laser for PDT and fluorescence diagnosis only, (2) enabling the possibility of on-line fluorescence measurements, and (3) exciting protoporphyrin molecules in deep tissue layers. Monte Carlo calculations were carried out to determine excitation and fluorescence phonon distribution in case of red and violet excitation radiation. The results show the possibility of depth-resolved measurements on the fluorophore distribution by variation of excitation wavelength. The high penetration depth of 633-nm radiation results in a higher ratio of the 700-nm protoporphyrin fluorescence of the xenotransplanted tumor It to Is compared with 407-nm excitation. No values greater than 1 for the ratio I/Is were found, however, in case of intravenous ALA injection even for red excitation. Therefore, a large amount of ALA will be metabolized in the skin and can cause photosensitivity of the patient when applied systematically. In contrast, protoporphyrin fluorescence limited to the pretreated skin area was detected in case of topically applied ALA to patients with mycosis funcoides and erythroplasy of Queyrat. The influence of remitted excitation light and of the spontaneous radiation from the laser as well as the possible excitation of foodbased degradation products of chlorophyll has to be considered in high-sensitivity fluorescence measurements.

  2. Utility Energy Services Contracts: Enabling Documents

    SciTech Connect

    2009-05-01

    Utility Energy Services Contracts: Enabling Documents provides materials that clarify the authority for Federal agencies to enter into utility energy services contracts (UESCs), as well as sample documents and resources to ease utility partnership contracting.

  3. An Architecture to Enable Future Sensor Webs

    NASA Technical Reports Server (NTRS)

    Mandl, Dan; Caffrey, Robert; Frye, Stu; Grosvenor, Sandra; Hess, Melissa; Chien, Steve; Sherwood, Rob; Davies, Ashley; Hayden, Sandra; Sweet, Adam

    2004-01-01

    A sensor web is a coherent set of distributed 'nodes', interconnected by a communications fabric, that collectively behave as a single dynamic observing system. A 'plug and play' mission architecture enables progressive mission autonomy and rapid assembly and thereby enables sensor webs. This viewgraph presentation addresses: Target mission messaging architecture; Strategy to establish architecture; Progressive autonomy with onboard sensor web; EO-1; Adaptive array antennas (smart antennas) for satellite ground stations.

  4. Saturation effects in fluorescence correlation spectroscopy

    NASA Astrophysics Data System (ADS)

    Davis, Lloyd M.; Shen, Guoqing; Ball, David A.

    2005-03-01

    Fluorescence correlation spectroscopy (FCS) could provide a more useful tool for intracellular studies and biological sample characterization if measurement times could be reduced. While an increase in laser power can enable an autocorrelation function (ACF) with adequate signal-to-noise to be acquired within a shorter measurement time, excitation saturation then leads to distortion of the ACF and systematic errors in the measurement results. An empirical method for achieving reduced systematic errors by employing a fitting function with an additional adjustable parameter has been previously introduced for two-photon FCS. Here we provide a unified physical explanation of excitation saturation effects for the three cases of continuous-wave, pulsed one-photon excitation, and two-photon excitation FCS. When the time between laser pulses is longer than the fluorescence lifetime, the signal rate at which excitation saturation occurs is lower for pulsed excitation than for cw excitation, and due to the disparate timescales of the photophysical processes following excitation, it is lower still for two-photon excitation. We use a single-molecule description of FCS to obtain improved analytical ACF fitting functions for the three cases. The fitting functions more accurately account for saturation effects than those previously employed without the need for an additional empirical parameter. Use of these fitting functions removes systematic errors and enables measurements to be acquired more quickly by use of higher laser powers. Increase of background, triplet photophysics, and the cases of scanning FCS and fluorescence cross-correlation spectroscopy are also discussed. Experimental results acquired with a custom built apparatus are presented.

  5. Combined fiber probe for fluorescence lifetime and Raman spectroscopy

    PubMed Central

    Dochow, Sebastian; Ma, Dinglong; Latka, Ines; Bocklitz, Thomas; Hartl, Brad; Bec, Julien; Fatakdawala, Hussain; Marple, Eric; Urmey, Kirk; Wachsmann-Hogiu, Sebastian; Schmitt, Michael; Marcu, Laura; Popp, Jürgen

    2016-01-01

    In this contribution we present a dual modality fiber optic probe combining fluorescence lifetime imaging (FLIm) and Raman spectroscopy for in vivo endoscopic applications. The presented multi-spectroscopy probe enables efficient excitation and collection of fluorescence lifetime signals for FLIm in the UV/visible wavelength region, as well as of Raman spectra in the near-IR for simultaneous Raman/FLIm imaging. The probe was characterized in terms of its lateral resolution and distance dependency of the Raman and FLIm signals. In addition, the feasibility of the probe for in vivo FLIm and Raman spectral characterization of tissue was demonstrated. PMID:26093843

  6. VCSEL-based flexible opto-fluidic fluorescence sensors

    NASA Astrophysics Data System (ADS)

    Kang, Dongseok; Gai, Boju; Yoon, Jongseung

    2016-03-01

    Flexible opto-fluidic fluorescence sensors based on microscale vertical cavity surface emitting lasers (micro-VCSELs) and silicon photodiodes (Si-PDs) are demonstrated, where arrays of 850 nm micro-VCSELs and thin film Si-PDs are heterogeneously integrated on a polyethylene terephthalate (PET) substrate by transfer printing, in conjunction with elastomeric fluidic channel. Enabled with optical isolation trenches together with wavelength- and angle-selective spectral filters implemented to suppress the absorption of excitation light, the integrated flexible fluorescence sensors exhibited significantly enhanced signal-to-background ratio, resulting in a maximum sensitivity of 5 × 10-5 wt% of infrared-absorbing organic dyes.

  7. Determination of biological activity from fluorescence-lifetime measurements in Saccharomyces cerevisiae

    NASA Astrophysics Data System (ADS)

    Rudek, F.; Baselt, T.; Lempe, B.; Taudt, C.; Hartmann, P.

    2015-03-01

    The importance of fluorescence lifetime measurement as an optical analysis tool is growing. Many applications already exist in order to determine the fluorescence lifetime, but the majority of these require the addition of fluorescence-active substances to enable measurements. Every usage of such foreign materials has an associated risk. This paper investigates the use of auto-fluorescing substances in Saccharomyces cerevisiae (Baker's yeast) as a risk free alternative to fluorescence-active substance enabled measurements. The experimental setup uses a nitrogen laser with a pulse length of 350 ps and a wavelength of 337 nm. The excited sample emits light due to fluorescence of NADH/NADPH and collagen. A fast photodiode collects the light at the output of an appropriate high-pass edge-filter at 400 nm. Fluorescence lifetimes can be determined from the decay of the measurement signals, which in turn characterizes the individual materials and their surrounding environment. Information about the quantity of the fluorescence active substances can also be measured based on the received signal intensity. The correlation between the fluorescence lifetime and the metabolic state of Saccharomyces cerevisiae was investigated and is presented here.

  8. Fluorescence suppression using micro-scale spatially offset Raman spectroscopy.

    PubMed

    Conti, Claudia; Botteon, Alessandra; Colombo, Chiara; Realini, Marco; Matousek, Pavel

    2016-09-21

    We present a new concept of fluorescence suppression in Raman microscopy based on micro-spatially offset Raman spectroscopy which is applicable to thin stratified turbid (diffusely scattering) matrices permitting the retrieval of the Raman signals of sublayers below intensely fluorescing turbid over-layers. The method is demonstrated to yield good quality Raman spectra with dramatically suppressed fluorescence backgrounds enabling the retrieval of Raman sublayer signals even in situations where conventional Raman microscopy spectra are fully overwhelmed by intense fluorescence. The concept performance was studied theoretically using Monte Carlo simulations indicating the potential of up to an order or two of magnitude suppression of overlayer fluorescence backgrounds relative to the Raman sublayer signals. The technique applicability was conceptually demonstrated on layered samples involving paints, polymers and stones yielding fluorescence suppression factors between 12 to above 430. The technique has potential applications in a number of analytical areas including cultural heritage, archaeology, polymers, food, pharmaceutical, biological, biomedical, forensics and catalytic sciences and quality control in manufacture.

  9. Wide Field-of-View Fluorescence Imaging of Coral Reefs

    PubMed Central

    Treibitz, Tali; Neal, Benjamin P.; Kline, David I.; Beijbom, Oscar; Roberts, Paul L. D.; Mitchell, B. Greg; Kriegman, David

    2015-01-01

    Coral reefs globally are declining rapidly because of both local and global stressors. Improved monitoring tools are urgently needed to understand the changes that are occurring at appropriate temporal and spatial scales. Coral fluorescence imaging tools have the potential to improve both ecological and physiological assessments. Although fluorescence imaging is regularly used for laboratory studies of corals, it has not yet been used for large-scale in situ assessments. Current obstacles to effective underwater fluorescence surveying include limited field-of-view due to low camera sensitivity, the need for nighttime deployment because of ambient light contamination, and the need for custom multispectral narrow band imaging systems to separate the signal into meaningful fluorescence bands. Here we describe the Fluorescence Imaging System (FluorIS), based on a consumer camera modified for greatly increased sensitivity to chlorophyll-a fluorescence, and we show high spectral correlation between acquired images and in situ spectrometer measurements. This system greatly facilitates underwater wide field-of-view fluorophore surveying during both night and day, and potentially enables improvements in semi-automated segmentation of live corals in coral reef photographs and juvenile coral surveys. PMID:25582836

  10. Fluorescence suppression using micro-scale spatially offset Raman spectroscopy.

    PubMed

    Conti, Claudia; Botteon, Alessandra; Colombo, Chiara; Realini, Marco; Matousek, Pavel

    2016-09-21

    We present a new concept of fluorescence suppression in Raman microscopy based on micro-spatially offset Raman spectroscopy which is applicable to thin stratified turbid (diffusely scattering) matrices permitting the retrieval of the Raman signals of sublayers below intensely fluorescing turbid over-layers. The method is demonstrated to yield good quality Raman spectra with dramatically suppressed fluorescence backgrounds enabling the retrieval of Raman sublayer signals even in situations where conventional Raman microscopy spectra are fully overwhelmed by intense fluorescence. The concept performance was studied theoretically using Monte Carlo simulations indicating the potential of up to an order or two of magnitude suppression of overlayer fluorescence backgrounds relative to the Raman sublayer signals. The technique applicability was conceptually demonstrated on layered samples involving paints, polymers and stones yielding fluorescence suppression factors between 12 to above 430. The technique has potential applications in a number of analytical areas including cultural heritage, archaeology, polymers, food, pharmaceutical, biological, biomedical, forensics and catalytic sciences and quality control in manufacture. PMID:27338230

  11. Aqueous ferrofluid of magnetite nanoparticles: Fluorescence labeling and magnetophoretic control.

    PubMed

    Sahoo, Yudhisthira; Goodarzi, Alireza; Swihart, Mark T; Ohulchanskyy, Tymish Y; Kaur, Navjot; Furlani, Edward P; Prasad, Paras N

    2005-03-10

    A method is presented for the preparation of a biocompatible ferrofluid containing dye-functionalized magnetite nanoparticles that can serve as fluorescent markers. This method entails the surface functionalization of magnetite nanoparticles using citric acid to produce a stable aqueous dispersion and the subsequent binding of fluorescent dyes to the surface of the particles. Several ferrofluid samples were prepared and characterized using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), BET surface area analysis, transmission electron microscopy (TEM), and SQUID magnetometry. In addition, confocal fluorescence microscopy was used to study the response of the fluorescent nanoparticles to an applied magnetic field and their uptake by cells in vitro. Results are presented on the distribution of particle sizes, the fluorescent and magnetic properties of the nanoparticles, and the nature of their surface bonds. Biocompatible ferrofluids with fluorescent nanoparticles enable optical tracking of basic processes at the cellular level combined with magnetophoretic manipulation and should be of substantial value to researchers engaged in both fundamental and applied biomedical research. PMID:16851439

  12. Fluorescent microthermographic imaging

    SciTech Connect

    Barton, D.L.

    1993-09-01

    In the early days of microelectronics, design rules and feature sizes were large enough that sub-micron spatial resolution was not needed. Infrared or IR thermal techniques were available that calculated the object`s temperature from infrared emission. There is a fundamental spatial resolution limitation dependent on the wavelengths of light being used in the image formation process. As the integrated circuit feature sizes began to shrink toward the one micron level, the limitations imposed on IR thermal systems became more pronounced. Something else was needed to overcome this limitation. Liquid crystals have been used with great success, but they lack the temperature measurement capabilities of other techniques. The fluorescent microthermographic imaging technique (FMI) was developed to meet this need. This technique offers better than 0.01{degrees}C temperature resolution and is diffraction limited to 0.3 {mu}m spatial resolution. While the temperature resolution is comparable to that available on IR systems, the spatial resolution is much better. The FMI technique provides better spatial resolution by using a temperature dependent fluorescent film that emits light at 612 nm instead of the 1.5 {mu}m to 12 {mu}m range used by IR techniques. This tutorial starts with a review of blackbody radiation physics, the process by which all heated objects emit radiation to their surroundings, in order to understand the sources of information that are available to characterize an object`s surface temperature. The processes used in infrared thermal imaging are then detailed to point out the limitations of the technique but also to contrast it with the FMI process. The FMI technique is then described in detail, starting with the fluorescent film physics and ending with a series of examples of past applications of FMI.

  13. Fluorescent temperature sensor

    DOEpatents

    Baker, Gary A [Los Alamos, NM; Baker, Sheila N [Los Alamos, NM; McCleskey, T Mark [Los Alamos, NM

    2009-03-03

    The present invention is a fluorescent temperature sensor or optical thermometer. The sensor includes a solution of 1,3-bis(1-pyrenyl)propane within a 1-butyl-1-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ionic liquid solvent. The 1,3-bis(1-pyrenyl)propane remains unassociated when in the ground state while in solution. When subjected to UV light, an excited state is produced that exists in equilibrium with an excimer. The position of the equilibrium between the two excited states is temperature dependent.

  14. Fluorescence in Astrophysical Plasmas

    NASA Astrophysics Data System (ADS)

    Hartman, Henrik

    Following the initial detection by Bowen in 1934 of the strong O III lines being due to accidental resonance with strong He II radiation, many strong spectral emission lines are explained as produced by fluorescence. Many of these are Fe II lines pumped by H Lyα, as a consequence of strong radiation from hydrogen and a favorable energy level structure for Fe II. The lines are observed in many types of objects with low density plasma components. The Weigelt condensations in the vicinity of the massive star Eta Carinae is one location where these lines are observed and can be studied in detail, as well as been used for diagnostics.

  15. Fluorescence analyzer for lignin

    DOEpatents

    Berthold, John W.; Malito, Michael L.; Jeffers, Larry

    1993-01-01

    A method and apparatus for measuring lignin concentration in a sample of wood pulp or black liquor comprises a light emitting arrangement for emitting an excitation light through optical fiber bundles into a probe which has an undiluted sensing end facing the sample. The excitation light causes the lignin concentration to produce fluorescent emission light which is then conveyed through the probe to analyzing equipment which measures the intensity of the emission light. Measures a This invention was made with Government support under Contract Number DOE: DE-FC05-90CE40905 awarded by the Department of Energy (DOE). The Government has certain rights in this invention.

  16. Fluorescent penetrant inspection

    NASA Technical Reports Server (NTRS)

    Sastri, Sankar

    1990-01-01

    The purpose of this experiment is to familiarize the student with fluorescent penetrant inspection and to relate it to classification of various defects. The penetrant method of nondestructive testing is a method for finding discontinuities open to the surface in solids and essentially nonporous bodies. The method employs a penetrating liquid which is applied over the surface and enters the discontinuity or crack. After the excess of penetrant has been cleaned from the surface, the penetrant which exudes or is drawn back out of the crack indicates the presence and location of a discontinuity. The experimental procedure is described.

  17. High-efficiency organic light-emitting diodes with fluorescent emitters

    NASA Astrophysics Data System (ADS)

    Nakanotani, Hajime; Higuchi, Takahiro; Furukawa, Taro; Masui, Kensuke; Morimoto, Kei; Numata, Masaki; Tanaka, Hiroyuki; Sagara, Yuta; Yasuda, Takuma; Adachi, Chihaya

    2014-05-01

    Fluorescence-based organic light-emitting diodes have continued to attract interest because of their long operational lifetimes, high colour purity of electroluminescence and potential to be manufactured at low cost in next-generation full-colour display and lighting applications. In fluorescent molecules, however, the exciton production efficiency is limited to 25% due to the deactivation of triplet excitons. Here we report fluorescence-based organic light-emitting diodes that realize external quantum efficiencies as high as 13.4-18% for blue, green, yellow and red emission, indicating that the exciton production efficiency reached nearly 100%. The high performance is enabled by utilization of thermally activated delayed fluorescence molecules as assistant dopants that permit efficient transfer of all electrically generated singlet and triplet excitons from the assistant dopants to the fluorescent emitters. Organic light-emitting diodes employing this exciton harvesting process provide freedom for the selection of emitters from a wide variety of conventional fluorescent molecules.

  18. Spatially selective photonic crystal enhanced fluorescence and application to background reduction for biomolecule detection assays

    PubMed Central

    Chaudhery, Vikram; Huang, Cheng-Sheng; Pokhriyal, Anusha; Polans, James; Cunningham, Brian T.

    2011-01-01

    By combining photonic crystal label-free biosensor imaging with photonic crystal enhanced fluorescence, it is possible to selectively enhance the fluorescence emission from regions of the PC surface based upon the density of immobilized capture molecules. A label-free image of the capture molecules enables determination of optimal coupling conditions of the laser used for fluorescence imaging of the photonic crystal surface on a pixel-by-pixel basis, allowing maximization of fluorescence enhancement factor from regions incorporating a biomolecule capture spot and minimization of background autofluorescence from areas between capture spots. This capability significantly improves the contrast of enhanced fluorescent images, and when applied to an antibody protein microarray, provides a substantial advantage over conventional fluorescence microscopy. Using the new approach, we demonstrate detection limits as low as 0.97 pg/ml for a representative protein biomarker in buffer. PMID:22109210

  19. Development of a quantitative fluorescence-based ligand-binding assay

    PubMed Central

    Breen, Conor J.; Raverdeau, Mathilde; Voorheis, H. Paul

    2016-01-01

    A major goal of biology is to develop a quantitative ligand-binding assay that does not involve the use of radioactivity. Existing fluorescence-based assays have a serious drawback due to fluorescence quenching that accompanies the binding of fluorescently-labeled ligands to their receptors. This limitation of existing fluorescence-based assays prevents the number of cellular receptors under investigation from being accurately measured. We have developed a method where FITC-labeled proteins bound to a cell surface are proteolyzed extensively to eliminate fluorescence quenching and then the fluorescence of the resulting sample is compared to that of a known concentration of the proteolyzed FITC-protein employed. This step enables the number of cellular receptors to be measured quantitatively. We expect that this method will provide researchers with a viable alternative to the use of radioactivity in ligand binding assays. PMID:27161290

  20. New Labour and the enabling state.

    PubMed

    Taylor, Ian

    2000-11-01

    The notion of the 'enabling state' gained currency in the UK during the 1990s as an alternative to the 'providing' or the welfare state. It reflected the process of contracting out in the NHS and compulsory competitive tendering (CCT) in local government during the 1980s, but was also associated with developments during the 1990s in health, social care and education in particular. The creation of an internal market in the NHS and the associated purchaser-provider split appeared to transfer 'ownership' of services increasingly to the providers - hospitals, General Practitioners (GPs) and schools. The mixed economy of care that was stimulated by the 1990 NHS and Community Care Act appeared to offer local authorities the opportunity to enable non state providers to offer care services in the community. The new service charters were part of the enablement process because they offered users more opportunity to influence provision. This article examines how far service providers were enabled and assesses the extent to which new Labour's policies enhance or reject the 'enabling state' in favour of more direct provision. PMID:11560707