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Sample records for bright green-emitting fluorescent

  1. Fluorescence Properties and Synthesis of Green-Emitting Tb3+-Activated Amorphous Calcium Silicate Phosphor by Ultraviolet Irradiation of 378 nm

    OpenAIRE

    Yoshiyuki Kojima; Masaaki Numazawa; Shinnosuke Kamei; Nobuyuki Nishimiya

    2012-01-01

    The excitation wavelength of conventional Tb3+-activated phosphor is near 270 nm. This study describes novel green-emitting Tb3+-activated amorphous calcium silicate by ultraviolet excitation at 378 nm. The Tb3+-activated amorphous calcium silicate was prepared by heating a sample of Tb3+-activated calcium silicate hydrate (CSH) at 900°C for 30 minutes. The emission wavelength of the resulting phosphor was 544 nm. The optimum excitation wavelength within the range 300–400 nm was 378 nm. The T...

  2. Crystallization and preliminary X-ray analysis of a monomeric mutant of Azami-Green (mAG), an Aequorea victoria green fluorescent protein-like green-emitting fluorescent protein from the stony coral Galaxea fascicularis

    International Nuclear Information System (INIS)

    A monomeric mutant of Azami-Green from G. fascicularis was expressed, purified and crystallized using the sitting-drop vapour-diffusion method. The crystal belonged to space group P1 and diffracted X-rays to 2.20 Å resolution. Monomeric Azami-Green (mAG) from the stony coral Galaxea fascicularis is the first monomeric green-emitting fluorescent protein that is not a derivative of Aequorea victoria green fluorescent protein (avGFP). mAG and avGFP are 27% identical in amino-acid sequence. Diffraction-quality crystals of recombinant mAG were obtained by the sitting-drop vapour-diffusion method using PEG 3350 as the precipitant. The mAG crystal diffracted X-rays to 2.20 Å resolution on beamline AR-NW12A at the Photon Factory (Tsukuba, Japan). The crystal belonged to space group P1, with unit-cell parameters a = 41.78, b = 51.72, c = 52.89 Å, α = 90.96, β = 103.41, γ = 101.79°. The Matthews coefficient (VM = 2.10 Å3 Da−1) indicated that the crystal contained two mAG molecules per asymmetric unit

  3. Bright and photostable cyanine-styryl chromophores with green and red fluorescence colour for DNA staining

    Science.gov (United States)

    Bohländer, Peggy R.; Wagenknecht, Hans-Achim

    2015-12-01

    The synthesis and optical characterisation of a series of green- and red-emitting cyanine and cyanine-styryl dyes is presented that were developed based on the cyanine-indole-quinolinium and based on the thiazole red type structure. For the green emitting fluorophores the quinolinium part was replaced by a pyridinium group. The bridge to the indole group was attached either to the 2-position or to the 4-position of the pyridinium moiety. For the red-emitting dyes the connection to the indole moiety is at the 4-position of the quinolinium part. In each set of dyes a methyl group at the indole-NH and/or a phenyl group at the 2-position of the indole part were introduced to tune the optical properties and photostability. Additionally, two dyes were modified with a cyano group to tune the photophysical properties and to enhance the photostabilities. The developed dyes show good photostabilities and bright green or red fluorescence intensities in the presence of DNA. Thus, these dyes represent important and promising candidates for fluorescent molecular imaging of nucleic acids inside living cells.

  4. Quantitative Brightness Analysis of Fluorescence Intensity Fluctuations in E. Coli.

    Directory of Open Access Journals (Sweden)

    Kwang-Ho Hur

    Full Text Available The brightness measured by fluorescence fluctuation spectroscopy specifies the average stoichiometry of a labeled protein in a sample. Here we extended brightness analysis, which has been mainly applied in eukaryotic cells, to prokaryotic cells with E. coli serving as a model system. The small size of the E. coli cell introduces unique challenges for applying brightness analysis that are addressed in this work. Photobleaching leads to a depletion of fluorophores and a reduction of the brightness of protein complexes. In addition, the E. coli cell and the point spread function of the instrument only partially overlap, which influences intensity fluctuations. To address these challenges we developed MSQ analysis, which is based on the mean Q-value of segmented photon count data, and combined it with the analysis of axial scans through the E. coli cell. The MSQ method recovers brightness, concentration, and diffusion time of soluble proteins in E. coli. We applied MSQ to measure the brightness of EGFP in E. coli and compared it to solution measurements. We further used MSQ analysis to determine the oligomeric state of nuclear transport factor 2 labeled with EGFP expressed in E. coli cells. The results obtained demonstrate the feasibility of quantifying the stoichiometry of proteins by brightness analysis in a prokaryotic cell.

  5. Wild Plum: novel particles of improved optical brightness and fluorescence.

    Science.gov (United States)

    Groathouse, Jordan; Barcena, Homar; Gustafson, Casey; Wilson, Mark V; Symonsbergen, David J; Lucas, Kerry A; Holmes, Andrea E

    2010-01-01

    A novel compound named Wild Plum fluoresces blue, and has been synthesized to camouflage skin imperfections, addressing the market demand for an anti-aging product. Wild Plum imparts optical brightness and fluorescence and can be used as an ingredient in cosmetic formulations. Skin appearance before and after application of Wild Plum compounds demonstrated an improved appearance of skin including a decreased number of wrinkles. When added to makeup, lotions, creams, and powders, Wild Plum conveys the glow of healthy youthful skin, replacing other costly or invasive alternatives such as cosmetic surgery. PMID:20716436

  6. Confidence intervals for concentration and brightness from fluorescence fluctuation measurements.

    Science.gov (United States)

    Pryse, Kenneth M; Rong, Xi; Whisler, Jordan A; McConnaughey, William B; Jiang, Yan-Fei; Melnykov, Artem V; Elson, Elliot L; Genin, Guy M

    2012-09-01

    The theory of photon count histogram (PCH) analysis describes the distribution of fluorescence fluctuation amplitudes due to populations of fluorophores diffusing through a focused laser beam and provides a rigorous framework through which the brightnesses and concentrations of the fluorophores can be determined. In practice, however, the brightnesses and concentrations of only a few components can be identified. Brightnesses and concentrations are determined by a nonlinear least-squares fit of a theoretical model to the experimental PCH derived from a record of fluorescence intensity fluctuations. The χ(2) hypersurface in the neighborhood of the optimum parameter set can have varying degrees of curvature, due to the intrinsic curvature of the model, the specific parameter values of the system under study, and the relative noise in the data. Because of this varying curvature, parameters estimated from the least-squares analysis have varying degrees of uncertainty associated with them. There are several methods for assigning confidence intervals to the parameters, but these methods have different efficacies for PCH data. Here, we evaluate several approaches to confidence interval estimation for PCH data, including asymptotic standard error, likelihood joint-confidence region, likelihood confidence intervals, skew-corrected and accelerated bootstrap (BCa), and Monte Carlo residual resampling methods. We study these with a model two-dimensional membrane system for simplicity, but the principles are applicable as well to fluorophores diffusing in three-dimensional solution. Using simulated fluorescence fluctuation data, we find the BCa method to be particularly well-suited for estimating confidence intervals in PCH analysis, and several other methods to be less so. Using the BCa method and additional simulated fluctuation data, we find that confidence intervals can be reduced dramatically for a specific non-Gaussian beam profile. PMID:23009839

  7. A Macrocyclic Fluorophore Dimer with Flexible Linkers: Bright Excimer Emission with a Long Fluorescence Lifetime.

    Science.gov (United States)

    Osaki, Hiroshi; Chou, Chih-Ming; Taki, Masayasu; Welke, Kai; Yokogawa, Daisuke; Irle, Stephan; Sato, Yoshikatsu; Higashiyama, Tetsuya; Saito, Shohei; Fukazawa, Aiko; Yamaguchi, Shigehiro

    2016-06-13

    Bright fluorescent molecules with long fluorescence lifetimes are important for the development of lifetime-based fluorescence imaging techniques. Herein, a molecular design is described for simultaneously attaining long fluorescence lifetime (τ) and high brightness (ΦF ×ɛ) in a system that features macrocyclic dimerization of fluorescent π-conjugated skeletons with flexible linkers. An alkylene-linked macrocyclic dimer of bis(thienylethynyl)anthracene was found to show excimer emission with a long fluorescence lifetime (τ≈19 ns) in solution, while maintaining high brightness. A comparison with various relevant derivatives revealed that the macrocyclic structure and the length of the alkylene chains play crucial roles in attaining these properties. In vitro time-gated imaging experiments were conducted as a proof-of-principle for the superiority of this macrocyclic fluorophore relative to the commercial fluorescent dye Alexa Fluor 488. PMID:27121201

  8. A novel green emitting phosphor Ca2GeO4:Tb3+

    International Nuclear Information System (INIS)

    A novel green emitting phosphor, Tb3+-doped Ca2GeO4 was prepared for the first time by a solid-state reaction. The phosphor showed prominent luminescence in green due to the magnetic dipole transition of 5D4→7F5. Structural characterization of the luminescent material was carried out with X-ray powder diffraction (XRD) analysis and field emission scanning electron microscopy (FE-SEM). Luminescence properties were analyzed by measuring the excitation and photoluminescence spectra. Photoluminescence measurements indicated that the phosphor exhibited bright green emission at about 541 and 550 nm under UV excitation. In addition, Al3+ or Li+ co-doping enhances the green emission from Ca2GeO4:Tb3+ by about 18 and 4 times, respectively, under UV excitation. The excellent luminescence properties make it a possible candidate for flat panel display application

  9. Near UV-Blue Excitable Green-Emitting Nanocrystalline Oxide

    Directory of Open Access Journals (Sweden)

    C. E. Rodríguez-García

    2011-01-01

    Full Text Available Green-emitting Eu-activated powders were produced by a two-stage method consisting of pressure-assisted combustion synthesis and postannealing in ammonia. The as-synthesized powders exhibited a red photoluminescence (PL peak located at =616 nm when excited with =395 nm UV. This emission peak corresponds to the 5D0→7F2 transition in Eu3+. After annealing in ammonia, the PL emission changed to an intense broad-band peak centered at =500 nm, most likely produced by 4f65d1→4f7 electronic transitions in Eu2+. This green-emitting phosphor has excitation band in the near UV-blue region (=300–450 nm. X-ray diffraction analysis reveals mainly the orthorhombic EuAlO3 and Al2O3 phases. Transmission electron microscopy observations showed that the grains are formed by faceted nanocrystals (~4 nm of polygonal shape. The excellent excitation and emission properties make these powders very promising to be used as phosphors in UV solid-state diodes coupled to activate white-emitting lamps.

  10. Fluorescent monomers: "bricks" that make a molecularly imprinted polymer "bright".

    Science.gov (United States)

    Wan, Wei; Wagner, Sabine; Rurack, Knut

    2016-03-01

    Molecularly imprinted polymers (MIPs) are potent and established recognition phases in separation and enrichment applications. Because of their robustness, versatility and format adaptability, they also constitute very promising sensing phases, especially when the active sensing element is directly integrated into the MIP. Fluorescent MIPs incorporating fluorescent monomers are perhaps the best developed and most successful approach here. This article reviews the state of the art in this field, discussing the pros and cons of the use of fluorescent dye and probe derivatives as such monomers, the different molecular interaction forces for template complexation, signalling modes and a variety of related approaches that have been realized over the years, including Förster resonance energy transfer processes, covalent imprinting, postmodification attachment of fluorescent units and conjugated polymers as MIPs; other measurement schemes and sensing chemistries that use MIPs and fluorescence interrogation to solve analytical problems (fluorescent competitive assays, fluorescent analytes, etc.) are not covered here. Throughout the article, photophysical processes are discussed to facilitate understanding of the effects that can occur when one is planning for a fluorescence response to happen in a constrained polymer matrix. The article concludes with a concise assessment of the suitability of the different formats for sensor realization. PMID:26613794

  11. Portable, Battery-Operated, Low-Cost, Bright Field and Fluorescence Microscope

    OpenAIRE

    Miller, Andrew R.; Davis, Gregory L.; Oden, Z. Maria; Razavi, Mohamad Reza; Fateh, Abolfazl; Ghazanfari, Morteza; Abdolrahimi, Farid; Poorazar, Shahin; Sakhaie, Fatemeh; Olsen, Randall J.; Bahrmand, Ahmad Reza; Pierce, Mark C.; Edward A. Graviss; Richards-Kortum, Rebecca

    2010-01-01

    This study describes the design and evaluation of a portable bright-field and fluorescence microscope that can be manufactured for $240 USD. The microscope uses a battery-operated LED-based flashlight as the light source and achieves a resolution of 0.8 µm at 1000× magnification in fluorescence mode. We tested the diagnostic capability of this new instrument to identify infections caused by the human pathogen, Mycobacterium tuberculosis. Sixty-four direct, decontaminated, and serially diluted...

  12. Targeted imaging of EGFR overexpressed cancer cells by brightly fluorescent nanoparticles conjugated with cetuximab.

    Science.gov (United States)

    Gao, Meng; Su, Huifang; Lin, Gengwei; Li, Shiwu; Yu, Xingsu; Qin, Anjun; Zhao, Zujin; Zhang, Zhenfeng; Tang, Ben Zhong

    2016-08-11

    To improve the treatment efficiency and reduce side effects in cancer therapy, accurate diagnosis of cancer cell types at a molecular level is highly desirable. Fluorescent nanoparticles (NPs) are especially suitable for detecting molecular biomarkers of cancer with advantages of superior brightness, easy decoration and high resolution. However, the conventional organic fluorophores, conjugated polymers, and inorganic quantum dots suffer from the drawbacks of aggregation-caused quenching (ACQ), low photostability, and heavy metal toxicity, respectively, which severely restrict their applications in NPs-based fluorescence imaging. To overcome these limitations, herein, we have developed fluorescent nanoparticles based on a t-BuPITBT-TPE fluorophore derived from aggregation-induced emission (AIE)-active tetraphenylethene. Through encapsulating t-BuPITBT-TPE within biocompatible DSPE-PEG and further decorating with a monoclonal antibody cetuximab (C225), the obtained t-BuPITBT-TPE-C225 NPs can be used for targeted imaging of non-small cell lung cancer cells with an overexpressed epidermal growth factor receptor (EGFR). The specific targeting ability of t-BuPITBT-TPE-C225 NPs has been well verified by confocal microscopy and flow cytometry experiments. The t-BuPITBT-TPE-C225 NPs have shown significant advantages in terms of highly efficient red emission, good bio-compatibility, and excellent photostability. This work provides a promising method for precise diagnosis of cancer cells by antibody-functionalized fluorescent NPs with high brightness. PMID:27468980

  13. Very bright orange fluorescent plants: endoplasmic reticulum targeting of orange fluorescent proteins as visual reporters in transgenic plants

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    Mann David GJ

    2012-05-01

    Full Text Available Abstract Background The expression of fluorescent protein (FP genes as real-time visual markers, both transiently and stably, has revolutionized plant biotechnology. A palette of colors of FPs is now available for use, but the diversity has generally been underutilized in plant biotechnology. Because of the green and far-red autofluorescent properties of many plant tissues and the FPs themselves, red and orange FPs (RFPs, and OFPs, respectfully appear to be the colors with maximum utility in plant biotechnology. Within the color palette OFPs have emerged as the brightest FP markers in the visible spectra. This study compares several native, near-native and modified OFPs for their “brightness” and fluorescence, therefore, their usability as marker genes in transgenic plant tissues. Results The OFPs DsRed2, tdTomato, mOrange and pporRFP were all expressed under the control of the CaMV 35S promoter in agroinfiltration-mediated transient assays in Nicotiana benthamiana. Each of these, as well as endoplasmic reticulum (ER-targeted versions, were stably expressed in transgenic Nicotiana tabacum and Arabidopsis thaliana. Congruent results were observed between transient and stable assays. Our results demonstrated that there are several adequate OFP genes available for plant transformation, including the new pporRFP, an unaltered tetramer from the hard coral Porites porites. When the tandem dimer tdTomato and the monomeric mOrange were targeted to the ER, dramatic, ca. 3-fold, increase in plant fluorescence was observed. Conclusions From our empirical data, and a search of the literature, it appears that tdTomato-ER and mOrange-ER are the two highest fluorescing FPs available as reporters for transgenic plants. The pporRFP is a brightly fluorescing tetramer, but all tetramer FPs are far less bright than the ER-targeted monomers we report here.

  14. Augmented microscopy: real-time overlay of bright-field and near-infrared fluorescence images

    Science.gov (United States)

    Watson, Jeffrey R.; Gainer, Christian F.; Martirosyan, Nikolay; Skoch, Jesse; Lemole, G. Michael, Jr.; Anton, Rein; Romanowski, Marek

    2015-10-01

    Intraoperative applications of near-infrared (NIR) fluorescent contrast agents can be aided by instrumentation capable of merging the view of surgical field with that of NIR fluorescence. We demonstrate augmented microscopy, an intraoperative imaging technique in which bright-field (real) and electronically processed NIR fluorescence (synthetic) images are merged within the optical path of a stereomicroscope. Under luminance of 100,000 lx, representing typical illumination of the surgical field, the augmented microscope detects 189 nM concentration of indocyanine green and produces a composite of the real and synthetic images within the eyepiece of the microscope at 20 fps. Augmentation described here can be implemented as an add-on module to visualize NIR contrast agents, laser beams, or various types of electronic data within the surgical microscopes commonly used in neurosurgical, cerebrovascular, otolaryngological, and ophthalmic procedures.

  15. Augmented microscopy: real-time overlay of bright-field and near-infrared fluorescence images.

    Science.gov (United States)

    Watson, Jeffrey R; Gainer, Christian F; Martirosyan, Nikolay; Skoch, Jesse; Lemole, G Michael; Anton, Rein; Romanowski, Marek

    2015-10-01

    Intraoperative applications of near-infrared (NIR) fluorescent contrast agents can be aided by instrumentation capable of merging the view of surgical field with that of NIR fluorescence. We demonstrate augmented microscopy, an intraoperative imaging technique in which bright-field (real) and electronically processed NIR fluorescence (synthetic) images are merged within the optical path of a stereomicroscope. Under luminance of 100,000 lx, representing typical illumination of the surgical field, the augmented microscope detects 189 nM concentration of indocyanine green and produces a composite of the real and synthetic images within the eyepiece of the microscope at 20 fps. Augmentation described here can be implemented as an add-on module to visualize NIR contrast agents, laser beams, or various types of electronic data within the surgical microscopes commonly used in neurosurgical, cerebrovascular, otolaryngological, and ophthalmic procedures. PMID:26440760

  16. Portable, battery-operated, low-cost, bright field and fluorescence microscope.

    Science.gov (United States)

    Miller, Andrew R; Davis, Gregory L; Oden, Z Maria; Razavi, Mohamad Reza; Fateh, Abolfazl; Ghazanfari, Morteza; Abdolrahimi, Farid; Poorazar, Shahin; Sakhaie, Fatemeh; Olsen, Randall J; Bahrmand, Ahmad Reza; Pierce, Mark C; Graviss, Edward A; Richards-Kortum, Rebecca

    2010-01-01

    This study describes the design and evaluation of a portable bright-field and fluorescence microscope that can be manufactured for $240 USD. The microscope uses a battery-operated LED-based flashlight as the light source and achieves a resolution of 0.8 microm at 1000x magnification in fluorescence mode. We tested the diagnostic capability of this new instrument to identify infections caused by the human pathogen, Mycobacterium tuberculosis. Sixty-four direct, decontaminated, and serially diluted smears were prepared from sputa obtained from 19 patients suspected to have M. tuberculosis infection. Slides were stained with auramine orange and evaluated as being positive or negative for M. tuberculosis with both the new portable fluorescence microscope and a laboratory grade fluorescence microscope. Concordant results were obtained in 98.4% of cases. This highly portable, low cost, fluorescence microscope may be a useful diagnostic tool to expand the availability of M. tuberculosis testing at the point-of-care in low resource settings. PMID:20694194

  17. Portable, battery-operated, low-cost, bright field and fluorescence microscope.

    Directory of Open Access Journals (Sweden)

    Andrew R Miller

    Full Text Available This study describes the design and evaluation of a portable bright-field and fluorescence microscope that can be manufactured for $240 USD. The microscope uses a battery-operated LED-based flashlight as the light source and achieves a resolution of 0.8 microm at 1000x magnification in fluorescence mode. We tested the diagnostic capability of this new instrument to identify infections caused by the human pathogen, Mycobacterium tuberculosis. Sixty-four direct, decontaminated, and serially diluted smears were prepared from sputa obtained from 19 patients suspected to have M. tuberculosis infection. Slides were stained with auramine orange and evaluated as being positive or negative for M. tuberculosis with both the new portable fluorescence microscope and a laboratory grade fluorescence microscope. Concordant results were obtained in 98.4% of cases. This highly portable, low cost, fluorescence microscope may be a useful diagnostic tool to expand the availability of M. tuberculosis testing at the point-of-care in low resource settings.

  18. Ultra-fast bright field and fluorescence imaging of the dynamics of micrometer-sized objects

    Science.gov (United States)

    Chen, Xucai; Wang, Jianjun; Versluis, Michel; de Jong, Nico; Villanueva, Flordeliza S.

    2013-06-01

    High speed imaging has application in a wide area of industry and scientific research. In medical research, high speed imaging has the potential to reveal insight into mechanisms of action of various therapeutic interventions. Examples include ultrasound assisted thrombolysis, drug delivery, and gene therapy. Visual observation of the ultrasound, microbubble, and biological cell interaction may help the understanding of the dynamic behavior of microbubbles and may eventually lead to better design of such delivery systems. We present the development of a high speed bright field and fluorescence imaging system that incorporates external mechanical waves such as ultrasound. Through collaborative design and contract manufacturing, a high speed imaging system has been successfully developed at the University of Pittsburgh Medical Center. We named the system "UPMC Cam," to refer to the integrated imaging system that includes the multi-frame camera and its unique software control, the customized modular microscope, the customized laser delivery system, its auxiliary ultrasound generator, and the combined ultrasound and optical imaging chamber for in vitro and in vivo observations. This system is capable of imaging microscopic bright field and fluorescence movies at 25 × 106 frames per second for 128 frames, with a frame size of 920 × 616 pixels. Example images of microbubble under ultrasound are shown to demonstrate the potential application of the system.

  19. Laser and Optical Properties of Green-Emitting ZnCdSe Quantum Dot Based Heterostructures

    Science.gov (United States)

    Vainilovich, Aliaksei G.; Lutsenko, E. V.; Yablonskii, G. P.; Sedova, I. V.; Sorokin, S. V.; Gronin, S. V.; Ivanov, S. V.; Kop'ev, P. S.

    Green-emitting laser diodes are in great demand for mobile projection media (pico-projector), navigation, underwater communication but they are still absent on the market. InGaN/GaN-based quantum well structures are approaching green spectral region by use of polar, semipolar as well as free-standing GaN substrates. However such heterostructures suffer from high laser thresholds with increase of indium content. A promising alternative way is the use of highly efficient green-emitting undoped ZnCdSe based quantum dot (QD) laser heterostructures optically pumped by blue InGaN laser diodes. Operation of blue-green laser converter based on MBE grown heterostructure with two ZnCdSe QD layers was shown for the first time in [1].

  20. Dependence of fluorescent protein brightness on protein concentration in solution and enhancement of it

    Science.gov (United States)

    Morikawa, Takamitsu J.; Fujita, Hideaki; Kitamura, Akira; Horio, Takashi; Yamamoto, Johtaro; Kinjo, Masataka; Sasaki, Akira; Machiyama, Hiroaki; Yoshizawa, Keiko; Ichimura, Taro; Imada, Katsumi; Nagai, Takeharu; Watanabe, Tomonobu M.

    2016-01-01

    Fluorescent proteins have been widely used in biology because of their compatibility and varied applications in living specimens. Fluorescent proteins are often undesirably sensitive to intracellular conditions such as pH and ion concentration, generating considerable issues at times. However, harnessing these intrinsic sensitivities can help develop functional probes. In this study, we found that the fluorescence of yellow fluorescent protein (YFP) depends on the protein concentration in the solution and that this dependence can be enhanced by adding a glycine residue in to the YFP; we applied this finding to construct an intracellular protein-crowding sensor. A Förster resonance energy transfer (FRET) pair, involving a cyan fluorescent protein (CFP) insensitive to protein concentration and a glycine-inserted YFP, works as a genetically encoded probe to evaluate intracellular crowding. By measuring the fluorescence of the present FRET probe, we were able to detect dynamic changes in protein crowding in living cells. PMID:26956628

  1. Innovative molecular-based fluorescent nanoparticles for multicolor single particle tracking in cells

    Science.gov (United States)

    Daniel, Jonathan; Godin, Antoine G.; Palayret, Matthieu; Lounis, Brahim; Cognet, Laurent; Blanchard-Desce, Mireille

    2016-03-01

    Based on an original molecular-based design, we present bright and photostable fluorescent organic nanoparticles (FONs) showing excellent colloidal stability in various aqueous environments. Complementary near-infrared emitting and green emitting FONs were prepared using a simple, fast and robust protocol. Both types of FONs could be simultaneously imaged at the single-particle level in solution as well as in biological environments using a monochromatic excitation and a dual-color fluorescence microscope. No evidence of acute cytotoxicity was found upon incubation of live cells with mixed solutions of FONs, and both types of nanoparticles were found internalized in the cells where their motion could be simultaneously tracked at video-rate up to minutes. These fluorescent organic nanoparticles open a novel non-toxic alternative to existing nanoparticles for imaging biological structures, compatible with live-cell experiments and specially fitted for multicolor single particle tracking.

  2. Synthesis, photophysical and electroluminescence properties of anthracene-based green-emitting conjugated polymers

    International Nuclear Information System (INIS)

    Anthracene-based conjugated polymers, which include carbazole and fluorene groups as host materials, are synthesized via Suzuki coupling reaction. Monomer feed ratios are varied in order to determine the effect of anthracene concentration on polymer properties. It is found that anthracene content plays a crucial role both in photoluminescence and electroluminescence properties of the polymers. All polymers exhibit efficient energy transfer from host groups to anthracene moieties in solid state. Excimer emission is observed for all polymers in devices, leading to green emission around 530–545 nm. The device structure ITO/PEDOT:PSS/Polymer/Alq3/LiF/Al based on a polymer with 5% anthracene-containing monomer produces a luminance efficiency of 1.9 cd/A. -- Highlights: • Anthracene containing conjugated polymers with host groups are synthesized. • Emission characteristics depend on the extent of energy transfer. • Polymers exhibit excimer emission, leading to green-emitting devices. • Polymer with 5% anthracene produces a luminance efficiency of 1.9 cd/A

  3. J-aggregation of a sulfur-substituted naphthalenediimide (NDI) with remarkably bright fluorescence.

    Science.gov (United States)

    Kar, Haridas; Ghosh, Suhrit

    2016-07-01

    This communication reveals the H-bonding driven supramolecular assembly of a sulfur-substituted naphthalenediimide leading to the formation of very strong (Tg > 90 °C) organogel in aliphatic hydrocarbons. Mechanistic investigation reveals nucleation-elongation pathway for self-assembly. Photophysical studies show explicit features of classical J-aggregation which reduces the non-radiative fluorescence rate constant considerably and thus results in a remarkable fluorescence enhancement (ΦPL increases from 1% to 30%) which is unprecedented in the entire NDI literature. PMID:27346798

  4. Simultaneous fluorescence and high-resolution bright-field imaging with aberration correction over a wide field-of-view with Fourier ptychographic microscopy (FPM) (Conference Presentation)

    Science.gov (United States)

    Chung, Jaebum; Kim, Jinho; Ou, Xiaoze; Horstmeyer, Roarke; Yang, Changhuei

    2016-03-01

    We present a method to acquire both fluorescence and high-resolution bright-field images with correction for the spatially varying aberrations over a microscope's wide field-of-view (FOV). First, the procedure applies Fourier ptychographic microscopy (FPM) to retrieve the amplitude and phase of a sample, at a resolution that significantly exceeds the cutoff frequency of the microscope objective lens. At the same time, FPM algorithm is able to leverage on the redundancy within the set of acquired FPM bright-field images to estimate the microscope aberrations, which usually deteriorate in regions further away from the FOV's center. Second, the procedure acquires a raw wide-FOV fluorescence image within the same setup. Lack of moving parts allows us to use the FPM-estimated aberration map to computationally correct for the aberrations in the fluorescence image through deconvolution. Overlaying the aberration-corrected fluorescence image on top of the high-resolution bright-field image can be done with accurate spatial correspondence. This can provide means to identifying fluorescent regions of interest within the context of the sample's bright-field information. An experimental demonstration successfully improves the bright-field resolution of fixed, stained and fluorescently tagged HeLa cells by a factor of 4.9, and reduces the error caused by aberrations in a fluorescence image by 31%, over a field of view of 6.2 mm by 9.3 mm. For optimal deconvolution, we show the fluorescence image needs to have a signal-to-noise ratio of ~18.

  5. Self-Assembled Gold Nanoclusters for Bright Fluorescence Imaging and Enhanced Drug Delivery.

    Science.gov (United States)

    Yahia-Ammar, Akram; Sierra, Daniel; Mérola, Fabienne; Hildebrandt, Niko; Le Guével, Xavier

    2016-02-23

    Nanoparticles combining enhanced cellular drug delivery with efficient fluorescence detection are important tools for the development of theranostic agents. Here, we demonstrate this concept by a simple, fast, and robust protocol of cationic polymer-mediated gold nanocluster (Au NCs) self-assembly into nanoparticles (NPs) of ca. 120 nm diameter. An extensive characterization of the monodisperse and positively charged NPs revealed pH-dependent swelling properties, strong fluorescence enhancement, and excellent colloidal and photostability in water, buffer, and culture medium. The versatility of the preparation is demonstrated by using different Au NC surface ligands and cationic polymers. Steady-state and time-resolved fluorescence measurements give insight into the aggregation-induced emission phenomenon (AIE) by tuning the Au NC interactions in the self-assembled nanoparticles using the pH-dependent swelling. In vitro studies in human monocytic cells indicate strongly enhanced uptake of the NPs compared to free Au NCs in endocytic compartments. The NPs keep their assembly structure with quite low cytotoxicity up to 500 μg Au/mL. Enhanced drug delivery is demonstrated by loading peptides or antibodies in the NPs using a one-pot synthesis. Fluorescence microscopy and flow cytometry confirmed intracellular colocalization of the biomolecules and the NP carriers with a respective 1.7-fold and 6.5-fold enhanced cellular uptake of peptides and antibodies compared to the free biomolecules. PMID:26845515

  6. Imaging magnetic scalar potentials by laser-induced fluorescence from bright and dark atoms

    Science.gov (United States)

    Fescenko, I.; Weis, A.

    2014-06-01

    We present a spectroscopic method for mapping two-dimensional distributions of magnetic field strengths (magnetic scalar potential lines) using charge-coupled device (CCD) recordings of the fluorescence patterns emitted by spin-polarized Cs vapour in a buffer gas exposed to inhomogeneous magnetic fields. The method relies on the position-selective destruction of spin polarization by magnetic resonances induced by multi-component oscillating magnetic fields, such that magnetic potential lines can be directly detected by the CCD camera. We also present a generic algebraic model allowing for the calculation of the fluorescence patterns and find excellent agreement with the experimental observations for three distinct inhomogeneous field topologies. The spatial resolution obtained with these proof-of-principle experiments is of the order of 1 mm. A substantial increase of spatial and magnetic field resolution is expected by deploying the method in a magnetically shielded environment.

  7. Imaging magnetic scalar potentials by laser-induced fluorescence from bright and dark atoms

    CERN Document Server

    Fescenko, Ilja

    2014-01-01

    We present a spectroscopic method for mapping two-dimensional distributions of magnetic field strengths (magnetic scalar potential lines) using CCD recordings of the fluorescence patterns emitted by spin-polarized Cs vapor in a buffer gas exposed to inhomogeneous magnetic fields. The method relies on the position-selective destruction of spin polarization by magnetic resonances induced by multi-component oscillating magnetic fields, such that magnetic potential lines can directly be detected by the CCD camera. We also present a generic algebraic model allowing the calculation of the fluorescence patterns and find excellent agreement with the experimental observations for three distinct inhomogeneous field topologies. The spatial resolution obtained with these proof-of-principle experiments is on the order of 1 mm. A substantial increase of spatial and magnetic field resolution is expected by deploying the method in a magnetically shielded environment.

  8. Imaging magnetic scalar potentials by laser-induced fluorescence from bright and dark atoms

    OpenAIRE

    Fescenko, Ilja; Weis, Antoine

    2014-01-01

    We present a spectroscopic method for mapping two-dimensional distributions of magnetic field strengths (magnetic scalar potential lines) using charge-coupled device (CCD) recordings of the fluorescence patterns emitted by spin-polarized Cs vapour in a buffer gas exposed to inhomogeneous magnetic fields. The method relies on the position-selective destruction of spin polarization by magnetic resonances induced by multi-component oscillating magnetic fields, such that magnetic potential lines ...

  9. Comparison of thin-layer chromatography, spectrofluorimetry and bright greenish-yellow fluorescence test for aflatoxin detection in corn

    Directory of Open Access Journals (Sweden)

    Elisabete Yurie Sataque Ono

    2010-06-01

    Full Text Available In this study the bright greenish-yellow fluorescence test, widely used by the corn milling industry, was compared to the thin-layer chromatography (TLC and spectrofluorimetry methods for aflatoxin detection in 40 corn samples naturally contaminated by the Aspergillus section Flavi. According to the corn processing industry criteria, all the samples were adequate for human and animal consumption by the bright greenish-yellow fluorescence test, but TLC and spectrofluorimetry analysis detected aflatoxins above the maximum tolerated limit (20 µg/kg in 7 and 8 samples, respectively. Aflatoxins were detected in 16 (40% corn samples by TLC, with levels ranging from 4.0 to 54.0 µg/kg (mean 19.97 ± 15.97 µg/kg, and in 25 (62.5% samples by spectrofluorimetry, with levels ranging from 1.0 to 58.66 µg/kg (mean 17.14 ± 17.81 µg/kg. The results indicated a good correlation (ρ = 0.97 between TLC and spectrofluorimetry for aflatoxin determination in naturally contaminated corn. The bright greenish-yellow fluorescence test was simple and quick, but it showed 20% false-negative results, suggesting its use only as screening method for detecting the suspected lots of grains that should be tested further for aflatoxin by more sensitive methods.Neste trabalho a contagem de fluorescência luminosa amarelo-esverdeada, amplamente utilizada pela indústria de processamento de milho, foi comparada à cromatografia em camada delgada (CCD e espectrofluorimetria para detecção de aflatoxinas em 40 amostras de milho naturalmente contaminadas por Aspergillus section Flavi. De acordo com os critérios da indústria processadora de milho, todas as amostras estavam adequadas para o consumo humano e animal pela contagem de fluorescência luminosa amarelo-esverdeada (CFLAE, porém as análises por CCD e espectrofluorimetria detectaram aflatoxinas acima do limite máximo tolerado (20 µg/kg em 7 e 8 amostras, respectivamente. As aflatoxinas foram detectadas em 16 (40

  10. A Novel Reporter Rat Strain That Conditionally Expresses the Bright Red Fluorescent Protein tdTomato.

    Directory of Open Access Journals (Sweden)

    Hiroyuki Igarashi

    Full Text Available Despite the strength of the Cre/loxP recombination system in animal models, its application in rats trails that in mice because of the lack of relevant reporter strains. Here, we generated a floxed STOP tdTomato rat that conditionally expresses a red fluorescent protein variant (tdTomato in the presence of exogenous Cre recombinase. The tdTomato signal vividly visualizes neurons including their projection fibers and spines without any histological enhancement. In addition, a transgenic rat line (FLAME that ubiquitously expresses tdTomato was successfully established by injecting intracytoplasmic Cre mRNA into fertilized ova. Our rat reporter system will facilitate connectome studies as well as the visualization of the fine structures of genetically identified cells for long periods both in vivo and ex vivo. Furthermore, FLAME is an ideal model for organ transplantation research owing to improved traceability of cells/tissues.

  11. A Novel Reporter Rat Strain That Conditionally Expresses the Bright Red Fluorescent Protein tdTomato.

    Science.gov (United States)

    Igarashi, Hiroyuki; Koizumi, Kyo; Kaneko, Ryosuke; Ikeda, Keiko; Egawa, Ryo; Yanagawa, Yuchio; Muramatsu, Shin-Ichi; Onimaru, Hiroshi; Ishizuka, Toru; Yawo, Hiromu

    2016-01-01

    Despite the strength of the Cre/loxP recombination system in animal models, its application in rats trails that in mice because of the lack of relevant reporter strains. Here, we generated a floxed STOP tdTomato rat that conditionally expresses a red fluorescent protein variant (tdTomato) in the presence of exogenous Cre recombinase. The tdTomato signal vividly visualizes neurons including their projection fibers and spines without any histological enhancement. In addition, a transgenic rat line (FLAME) that ubiquitously expresses tdTomato was successfully established by injecting intracytoplasmic Cre mRNA into fertilized ova. Our rat reporter system will facilitate connectome studies as well as the visualization of the fine structures of genetically identified cells for long periods both in vivo and ex vivo. Furthermore, FLAME is an ideal model for organ transplantation research owing to improved traceability of cells/tissues. PMID:27195805

  12. The structure of mAG, a monomeric mutant of the green fluorescent protein Azami-Green, reveals the structural basis of its stable green emission

    International Nuclear Information System (INIS)

    The crystal structure of a monomeric mutant of Azami-Green (mAG) from G. fascicularis was determined at 2.2 Å resolution. Monomeric Azami-Green (mAG) from the stony coral Galaxea fascicularis is the first known monomeric green-emitting fluorescent protein that is not a variant of Aequorea victoria green fluorescent protein (avGFP). These two green fluorescent proteins are only 27% identical in their amino-acid sequences. mAG is more similar in its amino-acid sequence to four fluorescent proteins: Dendra2 (a green-to-red irreversibly photoconverting fluorescent protein), Dronpa (a bright-and-dark reversibly photoswitchable fluorescent protein), KikG (a tetrameric green-emitting fluorescent protein) and Kaede (another green-to-red irreversibly photoconverting fluorescent protein). To reveal the structural basis of stable green emission by mAG, the 2.2 Å crystal structure of mAG has been determined and compared with the crystal structures of avGFP, Dronpa, Dendra2, Kaede and KikG. The structural comparison revealed that the chromophore formed by Gln62-Tyr63-Gly64 (QYG) and the fixing of the conformation of the imidazole ring of His193 by hydrogen bonds and van der Waals contacts involving His193, Arg66 and Thr69 are likely to be required for the stable green emission of mAG. The crystal structure of mAG will contribute to the design and development of new monomeric fluorescent proteins with faster maturation, brighter fluorescence, improved photostability, new colours and other preferable properties as alternatives to avGFP and its variants

  13. A bright cyan-excitable orange fluorescent protein facilitates dual-emission microscopy and enhances bioluminescence imaging in vivo.

    Science.gov (United States)

    Chu, Jun; Oh, Younghee; Sens, Alex; Ataie, Niloufar; Dana, Hod; Macklin, John J; Laviv, Tal; Welf, Erik S; Dean, Kevin M; Zhang, Feijie; Kim, Benjamin B; Tang, Clement Tran; Hu, Michelle; Baird, Michelle A; Davidson, Michael W; Kay, Mark A; Fiolka, Reto; Yasuda, Ryohei; Kim, Douglas S; Ng, Ho-Leung; Lin, Michael Z

    2016-07-01

    Orange-red fluorescent proteins (FPs) are widely used in biomedical research for multiplexed epifluorescence microscopy with GFP-based probes, but their different excitation requirements make multiplexing with new advanced microscopy methods difficult. Separately, orange-red FPs are useful for deep-tissue imaging in mammals owing to the relative tissue transmissibility of orange-red light, but their dependence on illumination limits their sensitivity as reporters in deep tissues. Here we describe CyOFP1, a bright, engineered, orange-red FP that is excitable by cyan light. We show that CyOFP1 enables single-excitation multiplexed imaging with GFP-based probes in single-photon and two-photon microscopy, including time-lapse imaging in light-sheet systems. CyOFP1 also serves as an efficient acceptor for resonance energy transfer from the highly catalytic blue-emitting luciferase NanoLuc. An optimized fusion of CyOFP1 and NanoLuc, called Antares, functions as a highly sensitive bioluminescent reporter in vivo, producing substantially brighter signals from deep tissues than firefly luciferase and other bioluminescent proteins. PMID:27240196

  14. Effect of Composition and Impurities on the Phosphorescence of Green-Emitting Alkaline Earth Aluminate Phosphor

    OpenAIRE

    Kim, Doory; Kim, Han-Eol; Kim, Chang-Hong

    2016-01-01

    Recent improvements to SrAl2O4:Eu2+, Dy3+ phosphors have enabled the use of luminescent hosts with a stable crystal structure and high physical and chemical stability, thus overcoming the bottleneck in the applicability of ZnS:Cu phosphors. However, enhancement of afterglow lifetime and brightness in SrAl2O4:Eu2+, Dy3+ phosphors remains a challenging task. Here, we have improved the afterglow characteristics in terms of persistence time and brightness by a systematic investigation of the comp...

  15. Effect of Composition and Impurities on the Phosphorescence of Green-Emitting Alkaline Earth Aluminate Phosphor.

    Science.gov (United States)

    Kim, Doory; Kim, Han-Eol; Kim, Chang-Hong

    2016-01-01

    Recent improvements to SrAl2O4:Eu2+, Dy3+ phosphors have enabled the use of luminescent hosts with a stable crystal structure and high physical and chemical stability, thus overcoming the bottleneck in the applicability of ZnS:Cu phosphors. However, enhancement of afterglow lifetime and brightness in SrAl2O4:Eu2+, Dy3+ phosphors remains a challenging task. Here, we have improved the afterglow characteristics in terms of persistence time and brightness by a systematic investigation of the composition of Eu-doped alkaline earth aluminate SrAl2O4:Eu2+, Dy3+ crystals. We found that a Dy3+/Eu2+ ratio of ~2.4 and ~0.935 mol Eu2+ (per mol of SrAl2O4) gave the brightest and longest emissions (11% and 9% increase for each). Doping with Si4+ also resulted in a slight increase in brightness up to ~15%. Doping with alkali metal or alkaline earth metal significantly enhanced the phosphorescence intensity. In particular, doping with 0.005 mol Li+ (per mol of SrAl2O4) alone boosted the phosphorescence intensity to 239% of the initial value, as compared to that observed for the non-doped crystal, while doping with 0.01 mol Mg2+ and 0.005 mol Li+ (per 1 mol SrAl2O4) boosted the phosphorescence intensity up to 313% of the initial value. The results of this investigation are expected to act as a guideline for the synthesis of bright and long persistent phosphors, and facilitate the development of persistent phosphors with afterglow characteristics superior to those of conventional phosphors. PMID:26731086

  16. Effect of Composition and Impurities on the Phosphorescence of Green-Emitting Alkaline Earth Aluminate Phosphor.

    Directory of Open Access Journals (Sweden)

    Doory Kim

    Full Text Available Recent improvements to SrAl2O4:Eu2+, Dy3+ phosphors have enabled the use of luminescent hosts with a stable crystal structure and high physical and chemical stability, thus overcoming the bottleneck in the applicability of ZnS:Cu phosphors. However, enhancement of afterglow lifetime and brightness in SrAl2O4:Eu2+, Dy3+ phosphors remains a challenging task. Here, we have improved the afterglow characteristics in terms of persistence time and brightness by a systematic investigation of the composition of Eu-doped alkaline earth aluminate SrAl2O4:Eu2+, Dy3+ crystals. We found that a Dy3+/Eu2+ ratio of ~2.4 and ~0.935 mol Eu2+ (per mol of SrAl2O4 gave the brightest and longest emissions (11% and 9% increase for each. Doping with Si4+ also resulted in a slight increase in brightness up to ~15%. Doping with alkali metal or alkaline earth metal significantly enhanced the phosphorescence intensity. In particular, doping with 0.005 mol Li+ (per mol of SrAl2O4 alone boosted the phosphorescence intensity to 239% of the initial value, as compared to that observed for the non-doped crystal, while doping with 0.01 mol Mg2+ and 0.005 mol Li+ (per 1 mol SrAl2O4 boosted the phosphorescence intensity up to 313% of the initial value. The results of this investigation are expected to act as a guideline for the synthesis of bright and long persistent phosphors, and facilitate the development of persistent phosphors with afterglow characteristics superior to those of conventional phosphors.

  17. Effect of Composition and Impurities on the Phosphorescence of Green-Emitting Alkaline Earth Aluminate Phosphor

    Science.gov (United States)

    Kim, Doory; Kim, Han-Eol; Kim, Chang-Hong

    2016-01-01

    Recent improvements to SrAl2O4:Eu2+, Dy3+ phosphors have enabled the use of luminescent hosts with a stable crystal structure and high physical and chemical stability, thus overcoming the bottleneck in the applicability of ZnS:Cu phosphors. However, enhancement of afterglow lifetime and brightness in SrAl2O4:Eu2+, Dy3+ phosphors remains a challenging task. Here, we have improved the afterglow characteristics in terms of persistence time and brightness by a systematic investigation of the composition of Eu-doped alkaline earth aluminate SrAl2O4:Eu2+, Dy3+ crystals. We found that a Dy3+/Eu2+ ratio of ~2.4 and ~0.935 mol Eu2+ (per mol of SrAl2O4) gave the brightest and longest emissions (11% and 9% increase for each). Doping with Si4+ also resulted in a slight increase in brightness up to ~15%. Doping with alkali metal or alkaline earth metal significantly enhanced the phosphorescence intensity. In particular, doping with 0.005 mol Li+ (per mol of SrAl2O4) alone boosted the phosphorescence intensity to 239% of the initial value, as compared to that observed for the non-doped crystal, while doping with 0.01 mol Mg2+ and 0.005 mol Li+ (per 1 mol SrAl2O4) boosted the phosphorescence intensity up to 313% of the initial value. The results of this investigation are expected to act as a guideline for the synthesis of bright and long persistent phosphors, and facilitate the development of persistent phosphors with afterglow characteristics superior to those of conventional phosphors. PMID:26731086

  18. Synthesis and characterization of Tb3+ doped MgSrAl10O17 green emitting phosphor

    International Nuclear Information System (INIS)

    There is a growing demand for economically viable phosphors for newly emerging display devices with on-going technological advancements. Various aluminates are used as hosts for doping rare earth ions in luminescent applications. Green emitting terbium-ion-doped MgSrAl10O17 phosphor prepared using the combustion method. An efficient phosphor can be prepared by this method at around 550°C in a very short time of few minutes. Further phosphor was analyzed by XRD for the confirmation of desired phase and purity. The morphology and structure of the phosphor were characterized by Scanning electron microscopy. The vibrational properties of MgSrAl10O17 phosphor was studied by FTIR

  19. Fluorescent properties of a blue-to green-emitting Ce3+, Tb3+ codoped amorphous calcium silicate phosphors

    International Nuclear Information System (INIS)

    Ce3+, Tb3+ codoped amorphous calcium silicate phosphor was prepared by heating (830 °C for 30 min) Ce3+, Tb3+ codoped calcium silicate hydrate phosphor formed by liquid-phase reaction. The excitation peak wavelength of the resulting phosphor was 330 nm and the emission peak wavelengths were at 544 nm, attributed to the 5D4→7F5 transition of Tb3+, and at 430–470 mm, attributed to Ce3+. The intensity ratio of the two peaks could be freely controlled by varying the Tb/Ca atomic ratio of the Ce3+, Tb3+ codoped amorphous calcium silicate phosphor, allowing light to be emitted over a wide range from blue to green. It was clarified that energy transfer exists from Ce3+ to Tb3+. - Graphical abstract: Ce3+, Tb3+ codoped calcium silicate hydrate phosphor was synthesized by liquid-phase reaction. This was heated at 830 °C to obtain a Ce3+, Tb3+ codoped amorphous calcium silicate phosphor. Under 330 nm excitation, this phosphor showed emission peaks at 430–470 nm and 542 nm. The luminescent color could be continuously changed blue to green with increasing Tb/Ca atomic ratio. It was clarified that electron transfer from Ce3+ to Tb3+ is occurring.

  20. Green-emitting nanoscaled borate phosphors Sr3RE2(BO3)4:Tb3+

    International Nuclear Information System (INIS)

    Three Tb3+ doped mixed strontium – rare earths borate phosphors of general formula Sr3RE2(BO3)4:Tb3+ (RE = Y, La or Gd) of 25–40 nm particle size were obtained by the Pechini sol–gel method, using citric acid and ethylene glycol as gel-forming agents. The structures of prepared materials were confirmed and characterized using X-ray powder diffraction and transmission electron microscopy. Photoluminescence properties, such as emission and excitation spectra and luminescence lifetimes of the phosphors, were measured. Excitation of the phosphors using different wavelengths in the UV range is possible. Lifetimes measured for the phosphors ranged from 2.2 to 2.7 ms. All of the Tb3+-doped phosphors show excellent luminescent properties, with a bright emission of green light under UV excitation. The color coordinates of emitted light on CIE1931 chromaticity diagram are close to those of National Television Standards Committee (NTSC) standard of green. - Graphical abstract: Display Omitted - Highlights: • Mixed strontium-rare earths borate Tb3+-doped nanoluminophors were obtained for the first time. • Optimal conditions for the synthesis of Sr3RE2(BO3)4:Tb3+ were found. • Photoluminescence properties of well-emitting products are discussed. • The color CIE coordinates of the nanosized (40 nm) particles were determined

  1. Fabrication and performance of ACTFEL display devices using manganese-doped zinc germanate as a green-emitting electroluminescent layer

    International Nuclear Information System (INIS)

    Alternating-current thin-film electroluminescent (ACTFEL) display devices fabricated using manganese-doped zinc germanate (Zn2GeO4:Mn) as a green-emitting electroluminescent layer material are described. The ACTFEL display devices were fabricated with a standard bottom emission structure having a multilayer stack of thin films in the metal/semiconductor/insulator/ metal (MSIM) configuration. The device was constructed on a transparent Corning glass substrate through which the emitted EL light passed. The Zn2GeO4:Mn emission layer was synthesized by using a RF magnetron sputter deposition method, followed by post-annealing at 700 .deg. C in air ambient for 1 hour. The obtained Zn2GeO4:Mn films were found to be polycrystalline with a rhombohedral crystal structure. A green emission spectrum with a maximum at approximately 538 nm was produced from the fabricated device. The chromaticity color coordinates of the EL emission were measured to be x = 0.308 and y = 0.657. The device demonstrated a sharp increase in the intensity of green EL emission upon increasing the AC peak voltage applied to the device above a threshold of 148 V.

  2. Mn2+ activated MgSrAl10O17 green-emitting phosphor-A luminescence and EPR study

    International Nuclear Information System (INIS)

    This paper reports on the luminescence and electron paramagnetic resonance (EPR) investigations on MgSrAl10O17:Mn2+ green-emitting phosphor. Single-phase MgSrAl10O17 was successfully synthesized by the one-step solution combustion route without the need for post-annealing at a higher temperature. Crystallization of the powder was confirmed by X-ray diffraction. The luminescence of Mn2+- activated MgSrAl10O17 shows a strong green-emission peak around 515 nm due to the 4T1→6A1 transition of Mn2+ ions under the excitation (453 nm). The EPR spectra of Mn2+ ions exhibit a sextet hyperfine structure centered at g ∼1.995. The Mn2+ ion occupies Mg sites which are in tetrahedral symmetry. The magnitude of the hyperfine splitting (A) indicates that Mn2+ is in a moderately ionic environment. The number of spins participating in resonance (N), the paramagnetic susceptibility (χ) and the zero-field splitting parameter (D) have been evaluated and discussed

  3. Vacuum Ultraviolet Spectral Investigations on Green-Emitting Ca(La,Gd)4Si3O13:Tb3+ Phosphors for PDP Applications

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In an effort to develop new green-emitting PDP phosphors with high efficiency, investigated were the synthesis, VUV photoluminescence (PL) spectra, optical properties, and chromaticity of Ca(La1-x-yTbxGdy)4Si3O13 phosphors by using synchrotron radiation. Upon analysis of the VUV spectroscopic and chromaticity investigations on the new green-emitting VUV phosphors, were an optimized composition achieved. The PLE spectral studies show that Ca(La1-x-yTbxGdy)4Si3O13 exhibit significant absorption in the VUV range. The VUV PL intensity was found to enhance with Gd3+-doping. Furthermore, the 1931 CIE chromaticity coordinates of Ca(La,Gd)4Si3O13:Tb were found to be (0.286, 0.548), as compared to (0.230, 0.712) for Zn2SiO4:Mn2+ as a reference. The potential application of Ca(La,Gd)4Si3O13:Tb as a new green-emitting PDP phosphor are being currently improving and evaluating.

  4. Preparation and luminescence of green-emitting ZnAl2O4:Mn2+ phosphor thin films

    International Nuclear Information System (INIS)

    Nanocrystalline Mn2+-doped zinc spinel (ZnAl2O4:Mn2+) green-emitting phosphor films were deposited on silicon substrate by sol–gel spin coating and subsequent heat treatment up to 1000 °C. The effects of dopant concentration and heat treatment on the optical and structural properties were investigated. The variations in sol viscosity with time, film thickness with number of layers were also examined. Thin films were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray microscopy, atomic force microscopy, and photoluminescence spectrum. Single-phase ZnAl2O4 started to crystallize at around 600 °C, with a normal spinel structure. On annealing at 1000 °C, the films had smooth surfaces with a nanocrystalline structure. Under UV or visible light excitation, the phosphor films exhibited an intense green emission band peaking at around 512 nm, corresponding to the typical 4T1 → 6A1 transition of tetrahedral Mn2+ ions. The most intense green emission was obtained by exciting at 456 nm. The emission intensity of films was highly dependent upon the excitation wavelength, crystallinity, dopant content, and deposition conditions. The results show that the ZnAl2O4:Mn2+ films have good potential for use as a green phosphor for displays and/or white light-emitting diodes. - Highlights: • ZnAl2O4:Mn2 + thin film phosphors have been synthesized by a sol–gel process. • The most intense green emission was obtained by exciting at 456 nm. • Photoluminescence is highly dependent on the crystallinity and doping content. • Emission intensity can also be modulated by controlling the film thickness

  5. Fluorescence-guided surgery of retroperitoneal-implanted human fibrosarcoma in nude mice delays or eliminates tumor recurrence and increases survival compared to bright-light surgery.

    Directory of Open Access Journals (Sweden)

    Fuminari Uehara

    Full Text Available The aim of this study is to determine if fluorescence-guided surgery (FGS can eradicate human fibrosarcoma growing in the retroperitoneum of nude mice. One week after retroperitoneal implantation of human HT1080 fibrosarcoma cells, expressing green fluorescent protein (GFP (HT-1080-GFP, in nude mice, bright-light surgery (BLS was performed on all tumor-bearing mice (n = 22. After BLS, mice were randomized into 2 treatment groups; BLS-only (n = 11 or the combination of BLS + FGS (n = 11. The residual tumors remaining after BLS were resected with FGS using a hand-held portable imaging system under fluorescence navigation. The average residual tumor area after BLS + FGS was significantly smaller than after BLS-only (0.4 ± 0.4 mm(2 and 10.5 ± 2.4 mm(2, respectively; p = 0.006. Five weeks after surgery, the fluorescent-tumor areas of BLS- and BLS + FGS-treated mice were 379 ± 147 mm(2 and 11.7 ± 6.9 mm(2, respectively, indicating that FGS greatly inhibited tumor recurrence compared to BLS. The combination of BLS + FGS significantly decreased fibrosarcoma recurrence compared to BLS-only treated mice (p < 0.001. Mice treated with BLS+FGS had a significantly higher disease-free survival rate than mice treated with BLS-only at five weeks after surgery. These results suggest that combination of BLS + FGS significantly reduced the residual fibrosarcoma volume after BLS and improved disease-free survival.

  6. Avaliação do método de triagem para análise de milho contaminado com aflatoxinas pela fluorescência amarelo-esverdeada brilhante (BGYF- Bright Greenish Yellow Fluorescence Evaluation of a screening method of aflatoxin in corn by Bright Greenish Yellow Fluorescence

    Directory of Open Access Journals (Sweden)

    M.E.T. PALOMINO

    1998-01-01

    Full Text Available A técnica da fluorescência amarelo-esverdeada brilhante (BGYF como método de triagem na avaliação de milho eventualmente contaminado com aflatoxina, utilizada por uma indústria alimentícia do Estado de São Paulo em 61 amostras de milho, foi comparada com a técnica BGYF padronizada, aplicada em laboratório antes e após trituração dos grãos e, também, com a técnica da cromatografia em camada delgada (CCD. Os resultados da indústria geraram menor número de resultados falso-positivos do que a técnica BGYF padronizada. Por outro lado, apenas os resultados da indústria apresentaram amostras falso-negativas, ao contrário da BGYF padronizada, que não as apresentou. Conclui-se que existe uma inadequação do número de pontos fluorescentes adotados como critério de rejeição em ambas as técnicas, devendo-se proceder estudos, com maior número de amostras, para determinar o número adequado de pontos fluorescentes a ser adotado como critério além de outros fatores que possam influenciar a metodologia.The bright greenish yellow fluorescence technique (BGYF is a screening method for the evaluation of corn occasionally contaminated by aflatoxins, used by an industry of the State of São Paulo on sixty one samples, was compared with laboratory results of the BGYF standard technique, before and after crushing the grains, and also with thin layer chromatographic analysis. The industry showed results with a smaller number of false positives than the BGYF standard technique. However, the industry showed false negative results and the BGYF standard technique did not. It was concluded that the number of fluorescent points adopted, as a rejection criterion, in both techniques, was inadequate and studies should be developed with more samples to determine the adequate number of fluorescent points to be adopted as a rejection criterion and the influence of other factors.

  7. Improving brightness and photostability of green and red fluorescent proteins for live cell imaging and FRET reporting.

    Science.gov (United States)

    Bajar, Bryce T; Wang, Emily S; Lam, Amy J; Kim, Bongjae B; Jacobs, Conor L; Howe, Elizabeth S; Davidson, Michael W; Lin, Michael Z; Chu, Jun

    2016-01-01

    Many genetically encoded biosensors use Förster resonance energy transfer (FRET) to dynamically report biomolecular activities. While pairs of cyan and yellow fluorescent proteins (FPs) are most commonly used as FRET partner fluorophores, respectively, green and red FPs offer distinct advantages for FRET, such as greater spectral separation, less phototoxicity, and lower autofluorescence. We previously developed the green-red FRET pair Clover and mRuby2, which improves responsiveness in intramolecular FRET reporters with different designs. Here we report the engineering of brighter and more photostable variants, mClover3 and mRuby3. mClover3 improves photostability by 60% and mRuby3 by 200% over the previous generation of fluorophores. Notably, mRuby3 is also 35% brighter than mRuby2, making it both the brightest and most photostable monomeric red FP yet characterized. Furthermore, we developed a standardized methodology for assessing FP performance in mammalian cells as stand-alone markers and as FRET partners. We found that mClover3 or mRuby3 expression in mammalian cells provides the highest fluorescence signals of all jellyfish GFP or coral RFP derivatives, respectively. Finally, using mClover3 and mRuby3, we engineered an improved version of the CaMKIIα reporter Camuiα with a larger response amplitude. PMID:26879144

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

    Science.gov (United States)

    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. Luminescence properties of a novel green emitting Ba2CaZn2Si6O17:Eu2+ phosphor for white light - Emitting diodes applications

    Science.gov (United States)

    Annadurai, G.; Kennedy, S. Masilla Moses; Sivakumar, V.

    2016-05-01

    A novel green emitting Ba2CaZn2Si6O17:Eu2+ (BCZSO:Eu2+) phosphor was synthesized using conventional high temperature solid state reaction method. Powder X-ray diffraction was carried out to confirm the phase formation of the synthesized phosphors. Photoluminescence emission spectrum was recorded under excitation at 340 nm. The BCZSO:Eu2+ phosphor exhibited an intense asymmetric green emission band around 502 nm which originated from the 4f65d1 → 4f7 transition of Eu2+ ion. The optimum doping concentration of Eu2+ was found to be 0.06 mol. The energy transfer mechanism among Eu2+ in BCZSO phosphor was found to be a dipole-dipole interaction, and the critical distance (RC) for the Eu2+ ions calculated by the concentration quenching and spectral overlap methods were 23.2 Å and 13.7 Å, respectively. The decay curve of BCZSO:Eu2+ phosphors were discussed. The CIE chromaticity coordinate values (x = 0.259, y = 0.463) of BCZSO:Eu2+ phosphor were located in green region and the correlated color temperature was 7571 K. All these properties gave an indication that BCZSO:Eu2+ phosphor could be a potential green-emitting phosphor for UV based white light emitting diodes.

  10. Synthesis and luminescent properties of a novel green-emitting Tb(III) complex and the excellent thermal stability for application

    Science.gov (United States)

    Yuan, Chen; Xie, Hongde; Cai, Haijun; Chen, Cuili; Cai, Peiqing; Seo, Hyo Jin

    2016-04-01

    A green-emitting Tb(III) complex based on siloxane-modified pressure sensitive adhesives (SPSA-Tb(III)) was successfully synthesized by emulsion polymerization. Siloxane-modified pressure sensitive adhesives (SPSA) were used as host materials. The structural coordination, photoluminescence excitation (PLE) and luminescence (PL) spectra, and thermal characterization of this luminescent polymer were investigated. The result from the FT-IR spectra reveals that SPSA have successfully coordinated with the Tb(III) ions. The luminescent analysis indicates that SPSA-Tb(III) displays Tb(III) typical emission peaks at 489, 545, 583, and 622 nm under the excitation of 369 nm. When monitored at 545 nm, strong and sharp excitation bands appear from 300 to 500 nm. And SPSA-Tb(III) has short lifetime (0.25 ms). Meanwhile, SPSA-Tb(III) exhibits high thermal stability (Td = 402 °C) owing to the high bond dissociation energy of Sisbnd O bonds. All the results suggest that it is expected to be used as a superior green-emitting material under high temperature.

  11. Synthesis and characterization of Tb{sup 3+} doped MgSrAl{sub 10}O{sub 17} green emitting phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Panse, V. R.; Dhoble, S. J. [Department of Physics, RTM Nagpur University (India); Kokode, N. S., E-mail: drns.kokode@gmail.com [Director,BCUD Gondwana University,Gadchiroli,Maharashtra (India)

    2013-12-16

    There is a growing demand for economically viable phosphors for newly emerging display devices with on-going technological advancements. Various aluminates are used as hosts for doping rare earth ions in luminescent applications. Green emitting terbium-ion-doped MgSrAl{sub 10}O{sub 17} phosphor prepared using the combustion method. An efficient phosphor can be prepared by this method at around 550°C in a very short time of few minutes. Further phosphor was analyzed by XRD for the confirmation of desired phase and purity. The morphology and structure of the phosphor were characterized by Scanning electron microscopy. The vibrational properties of MgSrAl{sub 10}O{sub 17} phosphor was studied by FTIR.

  12. Biosurfactant templated quantum sized fluorescent gold nanoclusters for in vivo bioimaging in zebrafish embryos.

    Science.gov (United States)

    S, Chandirasekar; C, Chandrasekaran; T, Muthukumarasamyvel; G, Sudhandiran; N, Rajendiran

    2016-07-01

    We report the biosurfactant (sodium cholate) templated bright bluish-green emitting gold nanoclusters (AuNCs) by green chemical approach. Optical properties of the AuNCs were studied using UV-vis and luminescence spectroscopy. Lifetime of the fluorescent AuNCs was measured using time correlated single photon counting technique (TCSPC). High-resolution transmission electron microscopy (HR-TEM) and dynamic light scattering (DLS) were used to measure the sizes of the clusters. In-vivo toxicity and bioimaging studies of sodium cholate (NaC) templated AuNCs were carried out at different developmental stages of zebrafish embryos. The survival rate, hatching rate, heart rate, malformation and apoptotic gene expression experiments shows no significant toxicity in developing embryos up to 100μL/mL of AuNCs concentration and the AuNCs stained embryos exhibited green fluorescence with high intensity over the period from 4 to 96hpf (hours post fertilization) which shows that AuNCs were stable in living organisms. PMID:27037785

  13. Sustainable, Rapid Synthesis of Bright-Luminescent CuInS2-ZnS Alloyed Nanocrystals: Multistage Nano-xenotoxicity Assessment and Intravital Fluorescence Bioimaging in Zebrafish-Embryos

    Science.gov (United States)

    Chetty, S. Shashank; Praneetha, S.; Basu, Sandeep; Sachidanandan, Chetana; Murugan, A. Vadivel

    2016-05-01

    Near-infrared (NIR) luminescent CuInS2-ZnS alloyed nanocrystals (CIZS-NCs) for highly fluorescence bioimaging have received considerable interest in recent years. Owing, they became a desirable alternative to heavy-metal based-NCs and organic dyes with unique optical properties and low-toxicity for bioimaging and optoelectronic applications. In the present study, bright and robust CIZS-NCs have been synthesized within 5 min, as-high-as 230 °C without requiring any inert-gas atmosphere via microwave-solvothermal (MW-ST) method. Subsequently, the in vitro and in vivo nano-xenotoxicity and cellular uptake of the MUA-functionalized CIZS-NCs were investigated in L929, Vero, MCF7 cell lines and zebrafish-embryos. We observed minimal toxicity and acute teratogenic consequences upto 62.5 μg/ml of the CIZS-NCs in zebrafish-embryos. We also observed spontaneous uptake of the MUA-functionalized CIZS-NCs by 3 dpf older zebrafish-embryos that are evident through bright red fluorescence-emission at a low concentration of 7.8 μg/mL. Hence, we propose that the rapid, low-cost, large-scale “sustainable” MW-ST synthesis of CIZS-NCs, is an ideal bio-nanoprobe with good temporal and spatial resolution for rapid labeling, long-term in vivo tracking and intravital-fluorescence-bioimaging (IVBI).

  14. Preparation of brightly fluorescent silica nanoparticles modified with lucigenin and chitosan, and their application to an aptamer-based sandwich assay for thrombin

    International Nuclear Information System (INIS)

    We report on the preparation of fluorescent silica nanoparticles (SiNPs) modified with chitosan and lucigenin by using a reverse microemulsion method. The introduction of chitosan to the lucigenin doped SiNPs is shown to improve the fluorescence quantum yield. The modified SiNPs were used as fluorescent markers in an aptamer-based method for selective determination of thrombin. In this protocol, thrombin was sandwiched between streptavidin-coated magnetic beads and the fluorescent SiNPs modified with a thrombin-binding aptamer. The method was successfully applied to the determination of thrombin in human serum and showed a detection limit as low as 0.02 nM. In our perception, the protocol presented here is promising in that such SiNPs may be applied to the sensitive fluorescent detection of other analytes by changing the corresponding aptamer. (author)

  15. Particle morphology and luminescence properties of green emitting Ba2SiO4:Eu2+ through a hydrothermal reaction route

    International Nuclear Information System (INIS)

    Green-emitting (Ba0.97Eu0.03)2SiO4 phosphors of different morphologies and particle sizes were prepared by varying the conditions of hydrothermal synthesis. Single-phase powders were obtained at 250 °C and autogeneous pressure followed by post annealing at 900 °C for 1 h. The ethanol/water ratio, hydrothermal reaction time, NaOH/Ba2+ ratio and silicon precursor strongly influence the particle size and morphology. The particle size, having spherical or needlelike shapes, ranges from 200 nm to 3 μm, depending on those parameters. These phosphors show strong absorption in the near UV range and the photoluminescence emission spectra consist of a strong broad green band centered around 514 nm. Furthermore, the emission intensities are dependent on the ethanol to water ratio, and 55–79% of that of micron-sized powders with a quantum efficiency of 94%. - Highlights: • (Ba0.97Eu0.03)2SiO4 with sub-micron particle sizes were prepared by hydrothermal synthesis. • Post-synthesis annealing at 900 °C results in single phase powders with a spherical morphology. • The emission intensities are 55–79% of micron-sized powders that have a quantum efficiency of 94%

  16. Particle morphology and luminescence properties of green emitting Ba{sub 2}SiO{sub 4}:Eu{sup 2+} through a hydrothermal reaction route

    Energy Technology Data Exchange (ETDEWEB)

    Han, J.K. [Condensed Matter Physics and Materials Sciences Department, Building 480, Brookhaven National Laboratory, Upton, NY 11973 (United States); Hannah, M.E.; Piquette, A. [OSRAM SYLVANIA Central Research, 71 Cherry Hill Dr. Beverly, MA 01915 (United States); Talbot, J.B. [University of California, San Diego, Dept. of Nanoengineering, La Jolla, CA 92093 (United States); Mishra, K.C. [OSRAM SYLVANIA Central Research, 71 Cherry Hill Dr. Beverly, MA 01915 (United States); McKittrick, J., E-mail: jmckittrick@ucsd.edu [University of California, San Diego, Dept. of Mechanical and Aerospace Engineering, La Jolla, CA 92093 (United States)

    2015-05-15

    Green-emitting (Ba{sub 0.97}Eu{sub 0.03}){sub 2}SiO{sub 4} phosphors of different morphologies and particle sizes were prepared by varying the conditions of hydrothermal synthesis. Single-phase powders were obtained at 250 °C and autogeneous pressure followed by post annealing at 900 °C for 1 h. The ethanol/water ratio, hydrothermal reaction time, NaOH/Ba{sup 2+} ratio and silicon precursor strongly influence the particle size and morphology. The particle size, having spherical or needlelike shapes, ranges from 200 nm to 3 μm, depending on those parameters. These phosphors show strong absorption in the near UV range and the photoluminescence emission spectra consist of a strong broad green band centered around 514 nm. Furthermore, the emission intensities are dependent on the ethanol to water ratio, and 55–79% of that of micron-sized powders with a quantum efficiency of 94%. - Highlights: • (Ba{sub 0.97}Eu{sub 0.03}){sub 2}SiO{sub 4} with sub-micron particle sizes were prepared by hydrothermal synthesis. • Post-synthesis annealing at 900 °C results in single phase powders with a spherical morphology. • The emission intensities are 55–79% of micron-sized powders that have a quantum efficiency of 94%.

  17. Luminescence and energy transfer of Mn2+ co-doped SrSi2O2N2:Eu2+ green-emitting phosphors

    International Nuclear Information System (INIS)

    Eu2+ and Mn2+ co-doped SrSi2O2N2 green-phosphors, with promising luminescent properties (examined by their powder diffuse reflection, photoluminescence excitation and emission spectra) suitable for UV converted white LEDs, were produced by high temperature solid-state reaction method. The produced materials exhibited intense broad absorption bands at 220-500 nm and a broad emission band centered at ca. 530 nm, attributed to 4f-5d transitions of Eu2+. The emission intensity of Eu2+ ions was greatly enhanced by introducing Mn2+ ions into SrSi2O2N2:Eu2+ due to the energy transfer from Mn2+ to Eu2+. The energy transfer probability from Mn2+ to Eu2+ depends strongly on the Mn2+ concentration, which is maximized at a Mn2+ concentration of 3 mol%. It drastically decreases for higher concentrations. The results indicated that SrSi2O2N2:Eu2+, Mn2+ is a promising green-emitting phosphor for white-light emitting diodes with near-UV LED chips.

  18. Preparation and luminescence of green-emitting ZnAl{sub 2}O{sub 4}:Mn{sup 2+} phosphor thin films

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Ing-Bang [Department of Materials Science and Engineering, National Formosa University, Huwei, Yunlin 632, Taiwan (China); Chang, Yee-Shin [Department of Electronic Engineering, National Formosa University, Huwei, Yunlin 632, Taiwan (China); Chen, Hao-Long [Department of Electronic Engineering, Kao Yuan University, Lujhu, Kaohsiung 821, Taiwan (China); Hwang, Ching Chiang [Department of Biotechnology, Mingdao University, Chang-Hua 52345, Taiwan (China); Jian, Chen-Jhu; Chen, Yu-Shiang [Department of Materials Science and Engineering, National Formosa University, Huwei, Yunlin 632, Taiwan (China); Tsai, Mu-Tsun, E-mail: mttsai@ms23.hinet.net [Department of Materials Science and Engineering, National Formosa University, Huwei, Yunlin 632, Taiwan (China)

    2014-11-03

    Nanocrystalline Mn{sup 2+}-doped zinc spinel (ZnAl{sub 2}O{sub 4}:Mn{sup 2+}) green-emitting phosphor films were deposited on silicon substrate by sol–gel spin coating and subsequent heat treatment up to 1000 °C. The effects of dopant concentration and heat treatment on the optical and structural properties were investigated. The variations in sol viscosity with time, film thickness with number of layers were also examined. Thin films were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray microscopy, atomic force microscopy, and photoluminescence spectrum. Single-phase ZnAl{sub 2}O{sub 4} started to crystallize at around 600 °C, with a normal spinel structure. On annealing at 1000 °C, the films had smooth surfaces with a nanocrystalline structure. Under UV or visible light excitation, the phosphor films exhibited an intense green emission band peaking at around 512 nm, corresponding to the typical {sup 4}T{sub 1} → {sup 6}A{sub 1} transition of tetrahedral Mn{sup 2+} ions. The most intense green emission was obtained by exciting at 456 nm. The emission intensity of films was highly dependent upon the excitation wavelength, crystallinity, dopant content, and deposition conditions. The results show that the ZnAl{sub 2}O{sub 4}:Mn{sup 2+} films have good potential for use as a green phosphor for displays and/or white light-emitting diodes. - Highlights: • ZnAl2O4:Mn2 + thin film phosphors have been synthesized by a sol–gel process. • The most intense green emission was obtained by exciting at 456 nm. • Photoluminescence is highly dependent on the crystallinity and doping content. • Emission intensity can also be modulated by controlling the film thickness.

  19. Living Colors in the Gray Mold Pathogen Botrytis cinerea: Codon-Optimized Genes Encoding Green Fluorescent Protein and mCherry, Which Exhibit Bright Fluorescence▿

    OpenAIRE

    Leroch, Michaela; Mernke, Dennis; Koppenhoefer, Dieter; Schneider, Prisca; Mosbach, Andreas; Doehlemann, Gunther; Hahn, Matthias

    2011-01-01

    The green fluorescent protein (GFP) and its variants have been widely used in modern biology as reporters that allow a variety of live-cell imaging techniques. So far, GFP has rarely been used in the gray mold fungus Botrytis cinerea because of low fluorescence intensity. The codon usage of B. cinerea genes strongly deviates from that of commonly used GFP-encoding genes and reveals a lower GC content than other fungi. In this study, we report the development and use of a codon-optimized versi...

  20. One-pot synthesis of water-dispersible Ag2S quantum dots with bright fluorescent emission in the second near-infrared window

    International Nuclear Information System (INIS)

    The second near-infrared window (NIR-II, wavelength of 1.0–1.4 μm) is optimal for the bioimaging of live animals due to their low albedo and endogenous autofluorescence. Herein, we report a facile and one-pot biomimetic synthesis approach to prepare water-dispersible NIR-II-emitting ultrasmall Ag2S quantum dots (QDs). Photoluminescence spectra showed that the emission peaks could be tuned from 1294 to 1050 nm as the size of the Ag2S QDs varied from 6.8 to 1.6 nm. The x-ray diffraction patterns and x-ray photoelectron spectra confirmed that the products were monoclinic α-Ag2S. Fourier transform infrared spectrograph analysis indicated that the products were protein-conjugated Ag2S QDs. Examination of cytotoxicity and the hemolysis test showed that the obtained Ag2S QDs had good biocompatibility, indicating that such a nanomaterial could be a new kind of fluorescent label for in vivo imaging. (paper)

  1. Green-emitting nanoscaled borate phosphors Sr{sub 3}RE{sub 2}(BO{sub 3}){sub 4}:Tb{sup 3+}

    Energy Technology Data Exchange (ETDEWEB)

    Shyichuk, A.; Lis, S., E-mail: blis@amu.edu.pl

    2013-07-15

    Three Tb{sup 3+} doped mixed strontium – rare earths borate phosphors of general formula Sr{sub 3}RE{sub 2}(BO{sub 3}){sub 4}:Tb{sup 3+} (RE = Y, La or Gd) of 25–40 nm particle size were obtained by the Pechini sol–gel method, using citric acid and ethylene glycol as gel-forming agents. The structures of prepared materials were confirmed and characterized using X-ray powder diffraction and transmission electron microscopy. Photoluminescence properties, such as emission and excitation spectra and luminescence lifetimes of the phosphors, were measured. Excitation of the phosphors using different wavelengths in the UV range is possible. Lifetimes measured for the phosphors ranged from 2.2 to 2.7 ms. All of the Tb{sup 3+}-doped phosphors show excellent luminescent properties, with a bright emission of green light under UV excitation. The color coordinates of emitted light on CIE1931 chromaticity diagram are close to those of National Television Standards Committee (NTSC) standard of green. - Graphical abstract: Display Omitted - Highlights: • Mixed strontium-rare earths borate Tb{sup 3+}-doped nanoluminophors were obtained for the first time. • Optimal conditions for the synthesis of Sr{sub 3}RE{sub 2}(BO{sub 3}){sub 4}:Tb{sup 3+} were found. • Photoluminescence properties of well-emitting products are discussed. • The color CIE coordinates of the nanosized (40 nm) particles were determined.

  2. Burkina Faso - BRIGHT II

    Data.gov (United States)

    Millenium Challenge Corporation — Millennium Challenge Corporation hired Mathematica Policy Research to conduct an independent evaluation of the BRIGHT II program. The three main research questions...

  3. 高亮度场发射荧光灯的制备及其性能测试%Fabrication and Properties of High Brightness Field Emission Fluorescence Lamp

    Institute of Scientific and Technical Information of China (English)

    郑旭丹; 胡利勤; 郭太良

    2011-01-01

    利用圆柱形结构的增强效应能提高丝状阴极场发射性能的这个特性,设计了场发射荧光灯.采用热敷法将配制好的碳纳米管(Carbon Nanotubes,CNT)浆料转移到镍丝(Ni)表面制备成丝状阴极,以及溶胶-凝胶法在圆柱形玻璃管内壁制备掺锡氧化铟(Indium Tin Oxide,ITO)薄膜作为阳极,制作场发射荧光灯.测试结果表明,该碳纳米管场发射荧光灯具有良好的场发射性能,开启电场低,仅为0.15 V/μm;CNT的场增强因子βCNT为1967;当驱动电压为4 000 V时,发光亮度达19 800cd/m2.这种亮度高、稳定性好、成本低的场发射荧光灯在照明光源领域具有很大的应用前景.%A novel cylindrical geometry carbon nanotubes (CNT)field emission fluorescence lamp (FEFL)was designed. The CNT paste was transfered to the surface of the nickel wire by thermal coating method ,and the indium tin oxide(ITO) thin film was fabricated in the cylinder glass pipe by sol-gel. The cylinder glass pipe with ITO film and phosphor was used as anode. The FEFL showed superior properties,such as low turn-on electric field of 0.15 V/μm,high brightness of 19 800 cd/m2 at the voltage 4 000 V,and large field enhancement factor of 1967. The FEFL is a very promising candidate as back light source.

  4. BrightFocus Foundation

    Science.gov (United States)

    ... size: A A Contrast En Español Donate BrightFocus Foundation Alzheimer’s Disease Research Macular Degeneration Research National Glaucoma ... Bovenkamp, Ph.D., Scientific Program Officer for BrightFocus Foundation, about the basic science and therapeutic research the ...

  5. Sunspot Bright Points

    CERN Document Server

    Choudhary, Debi Prasad

    2010-01-01

    We used the flux calibrated images through the Broad Band Filter Imager and Stokes Polarimeter data obtained with the Solar Optical Telescope onboard the Hinode spacecraft to study the properties of bright points in and around the sunspots. The well isolated bright points were selected and classified as umbral dot, peripheral umbral dot, penumbral grains and G-band bright point depending on their location. Most of the bright points are smaller than about 150 km. The larger points are mostly associated with the penumbral features. The bright points are not uniformly distributed over the umbra but preferentially located around the penumbral boundary and in the fast decaying parts of umbra. The color temperature of the bright points, derived using the continuum irradiance, are in the range of 4600 K to 6600 K with cooler ones located in the umbra. The temperature increases as a function of distance from the center to outside. The G-band, CN-band and CaII H flux of the bright points as a function of their blue ba...

  6. Fluorescent retroreflective signing of work zones : abstract

    NARCIS (Netherlands)

    Vos, A.P. de; Horst, A.R.A. van der; Alferdinck, J.W.A.M.; Kooi, F.L.

    1999-01-01

    Fluorescent retroreflective materials increase the brightness of traffic signs. In construction work zones a benefit is expected from the increased conspicuity of fluorescent retroreflective signs. Fluorescent material can be used instead of non-fluorescent materials both for the advance warning sig

  7. High Brightness Test Stand

    International Nuclear Information System (INIS)

    The High Brightness Test Stand is a 2 MeV, less than or equal to 10 kA electron accelerator module. This accelerator module, designed as an upgrade prototype for the Advanced Test Accelerator (ATA), combines solid state nonlinear magnetic drives with state-of-the-art induction linac technology. The facility serves a dual role, as it not only provides a test bed for this new technology, but is used to develop high brightness electron optics. We will both further describe the accelerator, as well as present some of the preliminary electron optics measurements

  8. Green emitting phosphors and blends thereof

    Science.gov (United States)

    Setlur, Anant Achyut; Siclovan, Oltea Puica; Nammalwar, Prasanth Kumar; Sathyanarayan, Ramesh Rao; Porob, Digamber G.; Chandran, Ramachandran Gopi; Heward, William Jordan; Radkov, Emil Vergilov; Briel, Linda Jane Valyou

    2010-12-28

    Phosphor compositions, blends thereof and light emitting devices including white light emitting LED based devices, and backlights, based on such phosphor compositions. The devices include a light source and a phosphor material as described. Also disclosed are phosphor blends including such a phosphor and devices made therefrom.

  9. The brightness of colour.

    Directory of Open Access Journals (Sweden)

    David Corney

    Full Text Available BACKGROUND: The perception of brightness depends on spatial context: the same stimulus can appear light or dark depending on what surrounds it. A less well-known but equally important contextual phenomenon is that the colour of a stimulus can also alter its brightness. Specifically, stimuli that are more saturated (i.e. purer in colour appear brighter than stimuli that are less saturated at the same luminance. Similarly, stimuli that are red or blue appear brighter than equiluminant yellow and green stimuli. This non-linear relationship between stimulus intensity and brightness, called the Helmholtz-Kohlrausch (HK effect, was first described in the nineteenth century but has never been explained. Here, we take advantage of the relative simplicity of this 'illusion' to explain it and contextual effects more generally, by using a simple Bayesian ideal observer model of the human visual ecology. We also use fMRI brain scans to identify the neural correlates of brightness without changing the spatial context of the stimulus, which has complicated the interpretation of related fMRI studies. RESULTS: Rather than modelling human vision directly, we use a Bayesian ideal observer to model human visual ecology. We show that the HK effect is a result of encoding the non-linear statistical relationship between retinal images and natural scenes that would have been experienced by the human visual system in the past. We further show that the complexity of this relationship is due to the response functions of the cone photoreceptors, which themselves are thought to represent an efficient solution to encoding the statistics of images. Finally, we show that the locus of the response to the relationship between images and scenes lies in the primary visual cortex (V1, if not earlier in the visual system, since the brightness of colours (as opposed to their luminance accords with activity in V1 as measured with fMRI. CONCLUSIONS: The data suggest that perceptions

  10. Bright Economic Prospects

    Institute of Scientific and Technical Information of China (English)

    Zhang Minqiu

    2004-01-01

    @@ India is expected to register an 8.2% growth rate for the 2003-04 fiscal year. The overall economic situation this year has been satisfactory despite the scaled down 6-6.5% growth rate for the new fiscal year due to oil price hikes, reduced monsoon volume and some 7% inflation. Judging from the following factors, bright prospects are in store for the country down the road.

  11. Fluorescence fluctuation immunoassay.

    Science.gov (United States)

    Elings, V B; Nicoli, D F; Briggs, J

    1983-01-01

    The homogeneous fluorescent immunoassay described above allows one to measure the brightness of fluorescently tagged carrier particles that are suspended in a background of free, unbound fluorescent sources. We have demonstrated the feasibility of our technique using a gentamicin competitive assay as well as idealized model systems. We have seen that the fluctuation-correlation method is able to discriminate against free background sources because each fluorescing particle in solution contributes to the correlation peak [Eq. (4)] with a weighting equal to the square of its respective intensity. Hence, a few very bright sources contribute disproportionately to the "signal" relative to many weak ones. To take advantage of this property, one would therefore design an assay that uses relatively larger carrier particles, each of which is capable of binding on the order of 10(3) to 10(4) tagged antibodies or antigens. Unfortunately, the nonlinear dependence of the correlation peak on the brightness of the fluorescing species causes the technique to be perturbed by carrier particle aggregation; the apparent bound fluorescence intensity increases with the extent of aggregation. The latter may be an unavoidable consequence of performing assays using raw blood serum, for example. The ultimate usefulness of this method will depend on its sensitivity and speed when applied to "real" assays of clinical significance. These characteristics will be influenced by a number of technical details. Given our limited experience with the method thus far, it would appear that its principal drawback is its relatively slow speed. In order to decrease the time needed for a reliable measurement, one must average the random fluctuations in the fluorescent intensity to zero more quickly. In principle, this can be accomplished by decreasing the shot noise by collecting a larger fraction of the fluorescent light, and increasing the sampling rate. The method requires rather complicated

  12. Quantitative measurement of brightness from living cells in the presence of photodepletion.

    Directory of Open Access Journals (Sweden)

    Kwang-Ho Hur

    Full Text Available The brightness of fluorescently labeled proteins provides an excellent marker for identifying protein interactions in living cells. Quantitative interpretation of brightness, however, hinges on a detailed understanding of the processes that affect the signal fluctuation of the fluorescent label. Here, we focus on the cumulative influence of photobleaching on brightness measurements in cells. Photobleaching within the finite volume of the cell leads to a depletion of the population of fluorescently labeled proteins with time. The process of photodepletion reduces the fluorescence signal which biases the analysis of brightness data. Our data show that even small reductions in the signal can introduce significant bias into the analysis of the data. We develop a model that quantifies the bias and introduce an analysis method that accurately determines brightness in the presence of photodepletion as verified by experiments with mammalian and yeast cells. In addition, photodepletion experiments with the fluorescent protein EGFP reveal the presence of a photoconversion process, which leads to a marked decrease in the brightness of the EGFP protein. We also identify conditions where the effect of EGFP's photoconversion on brightness experiments can be safely ignored.

  13. Quantitative Measurement of Brightness from Living Cells in the Presence of Photodepletion

    Science.gov (United States)

    Berk, Serkan; Angert, C. Isaac; Chen, Yan; Mueller, Joachim D.

    2014-01-01

    The brightness of fluorescently labeled proteins provides an excellent marker for identifying protein interactions in living cells. Quantitative interpretation of brightness, however, hinges on a detailed understanding of the processes that affect the signal fluctuation of the fluorescent label. Here, we focus on the cumulative influence of photobleaching on brightness measurements in cells. Photobleaching within the finite volume of the cell leads to a depletion of the population of fluorescently labeled proteins with time. The process of photodepletion reduces the fluorescence signal which biases the analysis of brightness data. Our data show that even small reductions in the signal can introduce significant bias into the analysis of the data. We develop a model that quantifies the bias and introduce an analysis method that accurately determines brightness in the presence of photodepletion as verified by experiments with mammalian and yeast cells. In addition, photodepletion experiments with the fluorescent protein EGFP reveal the presence of a photoconversion process, which leads to a marked decrease in the brightness of the EGFP protein. We also identify conditions where the effect of EGFP's photoconversion on brightness experiments can be safely ignored. PMID:24820174

  14. High brightness electron sources

    International Nuclear Information System (INIS)

    High energy physics accelerators and free electron lasers put increased demands on the electron beam sources. This paper describes the present research on attaining intense bright electron beams using photoinjectors. Recent results from the experimental programs will be given. The performance advantages and difficulties presently faced by researchers will be discussed, and the following topics will be covered. Progress has been made in photocathode materials, both in lifetime and quantum efficiency. Cesium telluride has demonstrated significantly longer lifetimes than cesium antimonide at 10-8 torr. However, the laser system is more difficult because cesium telluride requires quadrupled YLF instead of the doubled YLF required for cesium antimonide. The difficulty in using photoinjectors is primarily the drive laser, in particular the amplitude stability. Finally, emittance measurements of photoinjector systems can be complicated by the non-thermal nature of the electron beam. An example of the difficulty in measuring beam emittance is given

  15. Spectrally resolved multidepth fluorescence imaging

    Science.gov (United States)

    Luo, Yuan; Zervantonakis, Ioannis K.; Oh, Se Baek; Kamm, Roger D.; Barbastathis, George

    2011-09-01

    We present a multicolor fluorescence imaging modality to visualize in real-time tissue structures emitting multispectral fluorescent light from different focal depths. Each designated spectrum of fluorescent emission from a specific depth within a volumetric tissue is probed by a depth-spectrum selective holographic grating. The grating for each fluorescent color are multiplexed within a volume hologram, which enables simultaneously obtaining multicolored fluorescent information at different depths within a biological tissue sample. We demonstrate the imaging modality's ability to obtain laser-induced multicolored fluorescence images of a biological sample from different depths without scanning. We also experimentally demonstrate that the imaging modality can be simultaneously operated at both fluorescent and bright field modes to provide complementary information of volumetric tissue structures at different depths in real-time.

  16. Fluorescence fluctuation spectroscopy (FFS), pt.A

    CERN Document Server

    Tetin, Sergey

    2014-01-01

    This new volume of Methods in Enzymology continues the legacy of this premier serial by containing quality chapters authored by leaders in the field. This volume covers Fluorescence Fluctuation SpectroscopyContains chapters on such topics as Time-integrated fluorescence cumulant analysis, Pulsed Interleaved Excitation, and raster image correlation spectroscopy and number and brightness analysis.Continues the legacy of this premier serial with quality chapters authored by leaders in the fieldCovers fluorescence fluctuation spectroscopyContains chapte

  17. Teradiode's high brightness semiconductor lasers

    Science.gov (United States)

    Huang, Robin K.; Chann, Bien; Burgess, James; Lochman, Bryan; Zhou, Wang; Cruz, Mike; Cook, Rob; Dugmore, Dan; Shattuck, Jeff; Tayebati, Parviz

    2016-03-01

    TeraDiode is manufacturing multi-kW-class ultra-high brightness fiber-coupled direct diode lasers for industrial applications. A fiber-coupled direct diode laser with a power level of 4,680 W from a 100 μm core diameter, lasers. The fiber-coupled output corresponds to a Beam Parameter Product (BPP) of 3.5 mm-mrad and is the lowest BPP multi-kW-class direct diode laser yet reported. This laser is suitable for industrial materials processing applications, including sheet metal cutting and welding. This 4-kW fiber-coupled direct diode laser has comparable brightness to that of industrial fiber lasers and CO2 lasers, and is over 10x brighter than state-of-the-art direct diode lasers. We have also demonstrated novel high peak power lasers and high brightness Mid-Infrared Lasers.

  18. The EUVE bright source list

    Science.gov (United States)

    Stroozas, B.; Mcdonald, K.; Antia, B.; Mcdonald, J.; Wiercigroch, A.

    1993-01-01

    Initial results for bright extreme ultraviolet sources discovered during the EUVE all-sky and deep ecliptic surveys have been published as a Bright Source List (BSL) and released to the astronomical community with a recent NASA research announcement (NRA 93-OSS-02, Appendix F). This paper describes the data processing software, the EUVE survey data set, and the production of the BSL at the Center for EUV Astrophysics. The contents, format, and selection criteria for sources, the data processing strategy, some problems encountered, and a summary of the BSL results are presented.

  19. All things bright and beautiful

    OpenAIRE

    Brown, Chloe

    2012-01-01

    'All Things Bright and Beautiful' was exhibited in 20/21 Visual Arts Centre, Scunthorpe, which is sited in a 'redundant' church. The fundamental question that the exhibition explored concerned the role of 'the animal' within contemporary art and within secular society, which in turn hoped to prompt reflections on our understanding of the place of 'the human' in the world and in nature. If there is no divine order, as posited by the hymn 'All Things Bright and Beautiful', where does this leave...

  20. Bright Transients discovered by PSST

    Science.gov (United States)

    Smith, K. W.; Wright, D.; Smartt, S. J.; Huber, M.; Chambers, K. C.; Flewelling, H.; Willman, M.; Primak, N.; Schultz, A.; Gibson, B.; Magnier, E.; Waters, C.; Tonry, J.; Wainscoat, R. J.; Denneau, L.; Stalder, B.; Heinze, A.; Sherstyuk, A.; Foley, R. J.; Jha, S. W.; Rest, A.; Scolnic, D.

    2016-04-01

    Seven bright transients have been discovered as part of the Pan-STARRS Survey for Transients (PSST). Information on all objects discovered by the Pan-STARRS Survey for Transients is available at http://star.pst.qub.ac.uk/ps1threepi/ (see Huber et al. ATel #7153).

  1. Bright Transients discovered by PSST

    Science.gov (United States)

    Smith, K. W.; Wright, D.; Smartt, S. J.; Young, D. R.; Huber, M.; Chambers, K. C.; Flewelling, H.; Willman, M.; Primak, N.; Schultz, A.; Gibson, B.; Magnier, E.; Waters, C.; Tonry, J.; Wainscoat, R. J.; Foley, R. J.; Jha, S. W.; Rest, A.; Scolnic, D.

    2016-08-01

    Six bright transients have been discovered as part of the Pan-STARRS Survey for Transients (PSST). Information on all objects discovered by the Pan-STARRS Survey for Transients is available at http://star.pst.qub.ac.uk/ps1threepi/ (see Huber et al. ATel #7153).

  2. Fluorescent Approaches to High Throughput Crystallography

    Science.gov (United States)

    Pusey, Marc L.; Forsythe, Elizabeth; Achari, Aniruddha

    2006-01-01

    We have shown that 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 the presence of the probe at low concentrations does not affect the X-ray data quality or the crystallization behavior. The presence of the trace fluorescent label gives a number of advantages when used with high throughput crystallizations. 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 dark background. Non-protein structures, such as salt crystals, will not incorporate the probe and will not show up under fluorescent illumination. Brightly fluorescent crystals are readily found 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. We are now testing the use of 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 kinetics leading to non-structured phases may overwhelm and trap more slowly formed ordered assemblies, which subsequently show up as regions of brighter fluorescence intensity. Preliminary experiments with test proteins have resulted in the extraction of a number of crystallization conditions from screening outcomes based solely on the presence of bright fluorescent regions. Subsequent experiments will test this approach using a wider

  3. Combustion synthesis and photoluminescence properties of a novel blue-green-emitting Er{sup 3+} and Li{sup +} co-doped LaNbTiO{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xingshuang [State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China); Zhou, Guangjun, E-mail: gjzhou@sdu.edu.cn [State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China); Zhou, Juan [Center for Disease Prevention and Control of Jinan Military Command, Jinan 250014 (China); Zhou, Haifeng; Kong, Peng; Yu, Zhichao [State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China)

    2015-01-15

    Graphical abstract: - Highlights: • Novel LaNbTiO{sub 6}: Er{sup 3+}, Li{sup +} phosphor was synthesized by sol–gel combustion method. • The LaNbTiO{sub 6}: Er{sup 3+}, Li{sup +} phosphor exhibits blue-green emission under UV excitation. • The optimal Er{sup 3+} and Li{sup +} concentration are 3% and 1.5%, respectively. • Li{sup +}-doping could induce a remarkable increase of photoluminescence intensity. - Abstract: A single-phase blue-green light emitting phosphor, LaNbTiO{sub 6}: Er{sup 3+}, Li{sup +}, was synthesized by using a simple and facile sol–gel combustion approach. Its structure and photoluminescence (PL) properties were investigated as a function of Er{sup 3+} and Li{sup +} ion concentration. The luminous mechanisms of the Er{sup 3+} doping and Er{sup 3+}/Li{sup +} co-doping in the LaNbTiO{sub 6} host were also discussed, including the intra-4f-transitions of Er{sup 3+} and the charge compensation of Li{sup +}. The incorporation of Li{sup +} ions into LaNbTiO{sub 6} lattice further altered the local structure and symmetry of the crystals field around Er{sup 3+}. Concentration quenching occurred when Er{sup 3+} and Li{sup +} reached certain levels. Furthermore, the critical transfer distance of Er{sup 3+} → Er{sup 3+} in the phosphor was calculated. The absolute quantum efficiencies and the fluorescence decay time of the phosphors were studied. The phosphor produced blue-green light, presenting CIE chromaticity coordinates of (0.211, 0.277) and (0.214, 0.320)

  4. Helmholtz bright and boundary solitons

    International Nuclear Information System (INIS)

    We report, for the first time, exact analytical boundary solitons of a generalized cubic-quintic nonlinear Helmholtz (NLH) equation. These solutions have a linked-plateau topology that is distinct from conventional dark soliton solutions; their amplitude and intensity distributions are spatially delocalized and connect regions of finite and zero wave-field disturbances (suggesting also the classification as 'edge solitons'). Extensive numerical simulations compare the stability properties of recently derived Helmholtz bright solitons, for this type of polynomial nonlinearity, to those of the new boundary solitons. The latter are found to possess a remarkable stability characteristic, exhibiting robustness against perturbations that would otherwise lead to the destabilizing of their bright-soliton counterparts

  5. Helmholtz bright and boundary solitons

    Energy Technology Data Exchange (ETDEWEB)

    Christian, J M [Joule Physics Laboratory, School of Computing, Science and Engineering, Institute for Materials Research, University of Salford, Salford M5 4WT (United Kingdom); McDonald, G S [Joule Physics Laboratory, School of Computing, Science and Engineering, Institute for Materials Research, University of Salford, Salford M5 4WT (United Kingdom); Chamorro-Posada, P [Departmento de TeorIa de la Senal y Comunicaciones e IngenierIa Telematica, Universidad de Valladolid, ETSI Telecomunicacion, Campus Miguel Delibes s/n, 47011 Valladolid (Spain)

    2007-02-16

    We report, for the first time, exact analytical boundary solitons of a generalized cubic-quintic nonlinear Helmholtz (NLH) equation. These solutions have a linked-plateau topology that is distinct from conventional dark soliton solutions; their amplitude and intensity distributions are spatially delocalized and connect regions of finite and zero wave-field disturbances (suggesting also the classification as 'edge solitons'). Extensive numerical simulations compare the stability properties of recently derived Helmholtz bright solitons, for this type of polynomial nonlinearity, to those of the new boundary solitons. The latter are found to possess a remarkable stability characteristic, exhibiting robustness against perturbations that would otherwise lead to the destabilizing of their bright-soliton counterparts.

  6. Bright solitons from defocusing nonlinearities

    OpenAIRE

    Borovkova, Olga V.; Kartashov, Yaroslav; Torner Sabata, Lluís; Malomed, Boris A.

    2011-01-01

    We report that defocusing cubic media with spatially inhomogeneous nonlinearity, whose strength increases rapidly enough toward the periphery, can support stable bright localized modes. Such nonlinearity landscapes give rise to a variety of stable solitons in all three dimensions, including one-dimensional fundamental and multihump states, two-dimensional vortex solitons with arbitrarily high topological charges, and fundamental solitons in three dimensions. Solitons maintain their coherence ...

  7. Scintillation camera brightness calibration apparatus

    International Nuclear Information System (INIS)

    Circuitry is described for calibrating the brightness of a cathode ray tube display and recording apparatus comprising: 1) intensity control means for adjusting the intensity of the cathode ray tube beam; 2) light sensitive means disposed to receive light emitted from the cathode ray tube and generating a first electrical signal having a magnitude dependent upon the intensity of the emitted light; 3) reference signal generating means for generating a second electrical signal of predetermined magnitude; and 4) electrical signal comparison means coupled to the light sensitive means and the reference signal generating means for comparing the magnitude of the first and second electrical signals. (author)

  8. High-brightness electron injectors

    International Nuclear Information System (INIS)

    Free-electron laser (FEL) oscillators and synchrotron light sources require pulse trains of high peak brightness and, in some applications, high-average power. Recent developments in the technology of photoemissive and thermionic electron sources in rf cavities for electron-linac injector applications offer promising advances over conventional electron injectors. Reduced emittance growth in high peak-current electron injectors may be achieved by using high field strengths and by linearizing the radial component of the cavity electric field at the expense of lower shunt impedance

  9. High brightness beams and applications

    International Nuclear Information System (INIS)

    This paper describes the present research on attaining intense bright electron beams. Thermionic systems are briefly covered. Recent and past results from the photoinjector programs are given. The performance advantages and difficulties presently faced by researchers using photoinjectors is discussed. The progress that has been made in photocathode materials, both in lifetime and quantum efficiency, is covered. Finally, a discussion of emittance measurements of photoinjector systems and how the measurement is complicated by the non-thermal nature of the electron beam is presented

  10. How Bright Can Supernovae Get?

    Science.gov (United States)

    Kohler, Susanna

    2016-04-01

    Supernovae enormous explosions associated with the end of a stars life come in a variety of types with different origins. A new study has examined how the brightest supernovae in the Universe are produced, and what limits might be set on their brightness.Ultra-Luminous ObservationsRecent observations have revealed many ultra-luminous supernovae, which haveenergies that challenge our abilities to explain them usingcurrent supernova models. An especially extreme example is the 2015 discovery of the supernova ASASSN-15lh, which shone with a peak luminosity of ~2*1045 erg/s, nearly a trillion times brighter than the Sun. ASASSN-15lh radiated a whopping ~2*1052 erg in the first four months after its detection.How could a supernova that bright be produced? To explore the answer to that question, Tuguldur Sukhbold and Stan Woosley at University of California, Santa Cruz, have examined the different sources that could produce supernovae and calculated upper limits on the potential luminosities ofeach of these supernova varieties.Explosive ModelsSukhbold and Woosley explore multiple different models for core-collapse supernova explosions, including:Prompt explosionA stars core collapses and immediately explodes.Pair instabilityElectron/positron pair production at a massive stars center leads to core collapse. For high masses, radioactivity can contribute to delayed energy output.Colliding shellsPreviously expelled shells of material around a star collide after the initial explosion, providing additional energy release.MagnetarThe collapsing star forms a magnetar a rapidly rotating neutron star with an incredibly strong magnetic field at its core, which then dumps energy into the supernova ejecta, further brightening the explosion.They then apply these models to different types of stars.Setting the LimitThe authors show that the light curve of ASASSN-15lh (plotted in orange) can be described by a model (black curve) in which a magnetar with an initial spin period of 0.7 ms

  11. VERITAS Observations under Bright Moonlight

    CERN Document Server

    ,

    2015-01-01

    The presence of moonlight is usually a limiting factor for imaging atmospheric Cherenkov telescopes due to the high sensitivity of the camera photomultiplier tubes (PMTs). In their standard configuration, the extra noise limits the sensitivity of the experiment to gamma-ray signals and the higher PMT currents also accelerates PMT aging. Since fall 2012, observations have been carried out with VERITAS under bright moonlight (Moon illumination $> 35\\%$), in two observing modes, by reducing the voltage applied to the PMTs and with UV bandpass filters, which allow observations up to $\\sim80\\%$ Moon illumination resulting in $29\\%$ more observing time over the course of the year. In this presentation, we provide details of these new observing modes and their performance relative to the standard VERITAS observations.

  12. [Bright light therapy for elderly].

    Science.gov (United States)

    Okawa, Masako

    2015-06-01

    Bright light therapy (BLT) holds considerable promise for sleep problems in the elderly. BLT for community-dwelling patients with Alzheimer's disease showed significant improvement in sleep parameters. In the institutional setting, BLT was effective in reducing daytime nap duration. Morning BLT was found to advance the peak circadian rhythm and increase activity level in daytime and melatonin level at night. Light therapy could be used in combination with other nonpharmacological methods such as social activities, outside walking, physical exercises, which showed greater effects than independent BLT on sleep and cognitive function. BLT treatment strategy was proposed in the present paper. We should pay more attentions to BLT in community setting for mental and physical well-being. PMID:26065132

  13. The lowest surface brightness disc galaxy known

    International Nuclear Information System (INIS)

    The discovery of a galaxy with a prominent bulge and a dominant extremely low surface brightness disc component is reported. The profile of this galaxy is very similar to the recently discovered giant low surface brightness galaxy Malin 1. The disc central surface brightness is found to be ∼ 26.4 Rμ, some 1.5 mag fainter than Malin 1 and thus by far the lowest yet observed. (author)

  14. J Fluorescence

    OpenAIRE

    Resch-Genger, U.; Hoffmann, K.; Nietfeld, W; A. Engel; Neukammer, J.; Nitschke, R.; Ebert, P.; Macdonald, R

    2005-01-01

    The scope of this paper is to illustrate the need for an improved quality assurance in fluorometry. For this purpose, instrumental sources of error and their influences on the reliability and comparability of fluorescence data are highlighted for frequently used photoluminescence techniques ranging from conventional macro- and microfluorometry over fluorescence microscopy and flow cytometry to microarray technology as well as in vivo fluorescence imaging. Particularly, the need for and requir...

  15. Quantum communication with macroscopically bright nonclassical states.

    Science.gov (United States)

    Usenko, Vladyslav C; Ruppert, Laszlo; Filip, Radim

    2015-11-30

    We analyze homodyne detection of macroscopically bright multimode nonclassical states of light and propose their application in quantum communication. We observe that the homodyne detection is sensitive to a mode-matching of the bright light to the highly intense local oscillator. Unmatched bright modes of light result in additional noise which technically limits detection of Gaussian entanglement at macroscopic level. When the mode-matching is sufficient, we show that multimode quantum key distribution with bright beams is feasible. It finally merges the quantum communication with classical optical technology of visible beams of light. PMID:26698776

  16. Soliton fay identities: II. Bright soliton case

    International Nuclear Information System (INIS)

    We present a set of bilinear matrix identities that generalize the ones that have been used to construct the bright soliton solutions for various models. As an example of an application of these identities, we present a simple derivation of the N-bright soliton solutions for the Ablowitz–Ladik hierarchy. (paper)

  17. Incoherently coupled dark-bright photorefractive solitons

    Science.gov (United States)

    Chen, Zhigang; Segev, Mordechai; Coskun, Tamer H.; Christodoulides, Demetrios N.; Kivshar, Yuri S.; Afanasjev, Vsevolod V.

    1996-11-01

    We report the observation of incoherently coupled dark-bright spatial soliton pairs in a biased bulk photorefractive crystal. When such a pair is decoupled, the dark component evolves into a triplet structure, whereas the bright one decays into a self-defocusing beam.

  18. Spatial Brightness Perception of Trichromatic Stimuli

    Energy Technology Data Exchange (ETDEWEB)

    Royer, Michael P.; Houser, Kevin W.

    2012-11-16

    An experiment was conducted to examine the effect of tuning optical radiation on brightness perception for younger (18-25 years of age) and older (50 years of age or older) observers. Participants made forced-choice evaluations of the brightness of a full factorial of stimulus pairs selected from two groups of four metameric stimuli. The large-field stimuli were created by systematically varying either the red or the blue primary of an RGB LED mixture. The results indicate that light stimuli of equal illuminance and chromaticity do not appear equally bright to either younger or older subjects. The rank-order of brightness is not predicted by any current model of human vision or theory of brightness perception including Scotopic to Photopic or Cirtopic to Photopic ratio theory, prime color theory, correlated color temperature, V(λ)-based photometry, color quality metrics, linear brightness models, or color appearance models. Age may affect brightness perception when short-wavelength primaries are used, especially those with a peak wavelength shorter than 450 nm. The results suggest further development of metrics to predict brightness perception is warranted, and that including age as a variable in predictive models may be valuable.

  19. Soliton Fay identities. II. Bright soliton case

    OpenAIRE

    Vekslerchik, V. E.

    2015-01-01

    We present a set of bilinear matrix identities that generalize the ones that have been used to construct the bright soliton solutions for various models. As an example of an application of these identities, we present a simple derivation of the N-bright soliton solutions for the Ablowitz-Ladik hierarchy.

  20. Galaxy selection and the surface brightness distribution

    CERN Document Server

    McGaugh, S S; Schombert, J M

    1995-01-01

    Optical surveys for galaxies are biased against the inclusion of low surface brightness (LSB) galaxies. Disney (1976) suggested that the constancy of disk central surface brightness noticed by Freeman (1970) was not a physical result, but instead was an artifact of sample selection. Since LSB galaxies do exist, the pertinent and still controversial issue is if these newly discovered galaxies constitute a significant percentage of the general galaxy population. In this paper, we address this issue by determining the space density of galaxies as a function of disk central surface brightness. Using the physically reasonable assumption (which is motivated by the data) that central surface brightness is independent of disk scale length, we arrive at a distribution which is roughly flat (\\ie approximately equal numbers of galaxies at each surface brightness) faintwards of the Freeman (1970) value. Brightwards of this, we find a sharp decline in the distribution which is analogous to the turn down in the luminosity ...

  1. Bright, NIR-emitting Au23 from Au25: characterization and applications including biolabeling.

    Science.gov (United States)

    Muhammed, Madathumpady Abubaker Habeeb; Verma, Pramod Kumar; Pal, Samir Kumar; Kumar, R C Arun; Paul, Soumya; Omkumar, Ramakrishnapillai Vyomakesannair; Pradeep, Thalappil

    2009-10-01

    A novel interfacial route has been developed for the synthesis of a bright-red-emitting new subnanocluster, Au(23), by the core etching of a widely explored and more stable cluster, Au(25)SG(18) (in which SG is glutathione thiolate). A slight modification of this procedure results in the formation of two other known subnanoclusters, Au(22) and Au(33). Whereas Au(22) and Au(23) are water soluble and brightly fluorescent with quantum yields of 2.5 and 1.3 %, respectively, Au(33) is organic soluble and less fluorescent, with a quantum yield of 0.1 %. Au(23) exhibits quenching of fluorescence selectively in the presence of Cu(2+) ions and it can therefore be used as a metal-ion sensor. Aqueous- to organic-phase transfer of Au(23) has been carried out with fluorescence enhancement. Solvent dependency on the fluorescence of Au(23) before and after phase transfer has been studied extensively and the quantum yield of the cluster varies with the solvent used. The temperature response of Au(23) emission has been demonstrated. The inherent fluorescence of Au(23) was used for imaging human hepatoma cells by employing the avidin-biotin interaction. PMID:19711391

  2. Bright Sparks of Our Future!

    Science.gov (United States)

    Riordan, Naoimh

    2016-04-01

    My name is Naoimh Riordan and I am the Vice Principal of Rockboro Primary School in Cork City, South of Ireland. I am a full time class primary teacher and I teach 4th class, my students are aged between 9-10 years. My passion for education has developed over the years and grown towards STEM (Science, Technology, Engineering and Mathematics) subjects. I believe these subjects are the way forward for our future. My passion and beliefs are driven by the unique after school programme that I have developed. It is titled "Sparks" coming from the term Bright Sparks. "Sparks" is an after school programme with a difference where the STEM subjects are concentrated on through lessons such as Science, Veterinary Science Computer Animation /Coding, Eco engineering, Robotics, Magical Maths, Chess and Creative Writing. All these subjects are taught through activity based learning and are one-hour long each week for a ten-week term. "Sparks" is fully inclusive and non-selective which gives all students of any level of ability an opportunity to engage into these subjects. "Sparks" is open to all primary students in County Cork. The "Sparks" after school programme is taught by tutors from the different Universities and Colleges in Cork City. It works very well because the tutor brings their knowledge, skills and specialised equipment from their respective universities and in turn the tutor gains invaluable teaching practise, can trial a pilot programme in a chosen STEM subject and gain an insight into what works in the physical classroom.

  3. Designers predict a bright future

    International Nuclear Information System (INIS)

    As power plant designers and builders, there is a bright future for the industry. The demand for electricity will continue to grow, and the need for new plants will increase accordingly. But companies that develop and supply these plants must adapt to new ways of doing business if they expect to see the dawn of this new age. Several factors will have a profound effect on the generation and use of electricity in future years. Instant communications now reach all corners of the globe, making people everywhere aspire to a higher standard of living. The economic surge needed to satisfy these appetites will, in turn, be fed by a network of suppliers who are themselves restructuring to serve global markets, unimpeded by past nationalistic barriers to trade. The strong correlation between economic progress and the growing demand for electricity is well recognized. A ready supply of affordable electricity is a necessary underpinning for any economic expansion. As economies advance and jobs increase, electric demand grows geometrically, fueled by an ever-improving quality of life. Coupled with increasing demand is the worldwide trend toward privatization of the generation industry. The reasons may vary in different parts of the world, but the effect is the same--companies are battling intensely for the right to build or purchase generating facilities. Those companies, like the industry they serve, are themselves in a period of transition. Once a closed, monopolistic group of owners in a predominantly services-based market, they are, thanks to competitive forces, being driven steadily toward a product-based structure

  4. Fluorescent refrigeration

    Science.gov (United States)

    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.

  5. Bright boys the making of information technology

    CERN Document Server

    Green, Tom

    2010-01-01

    Everything has a beginning. None was more profound-and quite as unexpected-than Information Technology. Here for the first time is the untold story of how our new age came to be and the bright boys who made it happen. What began on the bare floor of an old laundry building eventually grew to rival in size the Manhattan Project. The unexpected consequence of that journey was huge---what we now know as Information Technology. For sixty years the bright boys have been totally anonymous while their achievements have become a way of life for all of us. "Bright Boys" brings them home. By 1950 they'd

  6. The solar brightness temperature at millimeter wavelengths

    Science.gov (United States)

    Kuseski, R. A.; Swanson, P. N.

    1976-01-01

    Measurements of the brightness temperature of the sun near 36 GHz and 93 GHz were made using the new moon as a calibration source. Provided the brightness temperature of the moon is known and all measurements are reduced to the same zenith angle, a simple expression can be used for the sun-to-new moon ratio which is independent of antenna gain, atmospheric absorption and reemission, and radiometer calibration constants. This ratio was measured near 36 GHz and at two frequencies near 93 GHz with a Dicke switched superheterodyne radiometer system and a 2.4 m Cassegrain antenna. The slopes of the solar brightness temperature spectrum based on these ratios were measured. The absolute solar brightness spectrum derived from all current available measurements supplemented by the present ones is also plotted and discussed.

  7. A spectroscopic atlas of bright stars

    CERN Document Server

    Martin, Jack

    2009-01-01

    Suitable for amateur astronomers interested in practical spectroscopy or spectrography, this reference book identifies more than 70 (northern hemisphere) bright stars that are suitable observational targets. It provides finder charts for locating these sometimes-familiar stars.

  8. Surface Brightness Profiles of Seyfert Galaxies

    CERN Document Server

    Tugay, A V

    2014-01-01

    We built r-band surface brightness profiles by SDSS data for 16 Seyfert galaxies observed in Crimean Astrophysical Observatory. Obtained profiles can be used for finding more accurate lightcurves for these galaxies.

  9. Brightness of synchrotron radiation from wigglers

    CERN Document Server

    Geloni, Gianluca; Saldin, Evgeni

    2014-01-01

    According to literature, while calculating the brightness of synchrotron radiation from wigglers, one needs to account for the so called `depth-of-field' effects. In fact, the particle beam cross section varies along the wiggler. It is usually stated that the effective photon source size increases accordingly, while the brightness is reduced. Here we claim that this is a misconception originating from an analysis of the wiggler source based on geometrical arguments, regarded as almost self-evident. According to electrodynamics, depth-of-field effects do not exist: we demonstrate this statement both theoretically and numerically, using a well-known first-principle computer code. This fact shows that under the usually accepted approximations, the description of the wiggler brightness turns out to be inconsistent even qualitatively. Therefore, there is a need for a well-defined procedure for computing the brightness from a wiggler source. We accomplish this task based on the use of a Wigner function formalism. I...

  10. Safranine fluorescent staining of wood cell walls.

    Science.gov (United States)

    Bond, J; Donaldson, L; Hill, S; Hitchcock, K

    2008-06-01

    Safranine is an azo dye commonly used for plant microscopy, especially as a stain for lignified tissues such as xylem. Safranine fluorescently labels the wood cell wall, producing green/yellow fluorescence in the secondary cell wall and red/orange fluorescence in the middle lamella (ML) region. We examined the fluorescence behavior of safranine under blue light excitation using a variety of wood- and fiber-based samples of known composition to interpret the observed color differentiation of different cell wall types. We also examined the basis for the differences in fluorescence emission using spectral confocal microscopy to examine lignin-rich and cellulose-rich cell walls including reaction wood and decayed wood compared to normal wood. Our results indicate that lignin-rich cell walls, such as the ML of tracheids, the secondary wall of compression wood tracheids, and wood decayed by brown rot, tend to fluoresce red or orange, while cellulose-rich cell walls such as resin canals, wood decayed by white rot, cotton fibers and the G-layer of tension wood fibers, tend to fluoresce green/yellow. This variation in fluorescence emission seems to be due to factors including an emission shift toward red wavelengths combined with dye quenching at shorter wavelengths in regions with high lignin content. Safranine fluorescence provides a useful way to differentiate lignin-rich and cellulose-rich cell walls without counterstaining as required for bright field microscopy. PMID:18802812

  11. The surface brightness of spiral galaxies

    International Nuclear Information System (INIS)

    The intrinsic surface brightness Ssub(e) of 500 disc galaxies (0<=T<=9) drawn from the Second Reference Catalogue is computed and it is shown that Ssub(e) does not correlate significantly with Msub(B), (B-V) or type. This is consistent with the notion that there is a heavy selection bias in favour of disc galaxies with that particular surface brightness which allows inclusion in the catalogue over the largest volume of space. (author)

  12. The surface brightness of spiral galaxies

    International Nuclear Information System (INIS)

    It is proposed that Freeman's discovery that the extrapolated central surface brightness of spiral galaxies is approximately constant can be simply explained if the galaxies contain a spheroidal component which dominates the light in their outer isophotes. Calculations of an effective central surface brightness indicate a wide spread of values. This requires either a wide spread in disc properties or significant spheroidal components or, most probably, both. (author)

  13. Development of a high brightness ion source

    International Nuclear Information System (INIS)

    The brightness and emittance of an ion beam can depend on the ion temperature, aberrations and scattering, as well as other factors. However, it is the ion temperature which determines the irreducible minimum value of the emittance and hence brightness, as the other components can be eliminated by careful design. An ion source design is presented which has attained this minimum value for the emittance; the dependence of the ion temperature on the plasma source parameters is discussed

  14. Bright perspectives for nuclear photonics

    International Nuclear Information System (INIS)

    With the advent of new high-power, short-pulse laser facilities in combination with novel technologies for the production of highly brilliant, intense γ beams (like, e.g., Extreme Light Infrastructure - Nuclear Physics (ELI-NP) in Bucharest, MEGaRay in Livermore or a planned upgrade of the HIγS facility at Duke University), unprecedented perspectives will open up in the coming years for photonuclear physics both in basic sciences as in various fields of applications. Ultra-high sensitivity will be enabled by an envisaged increase of the γ-beam spectral density from the presently typical 102γ/eVs to about 104γ/eVs, thus enabling a new quality of nuclear photonics, assisted by new γ-optical elements. Photonuclear reactions with highly brilliant γ beams will allow to produce radioisotopes for nuclear medicine with much higher specific activity and/or more economically than with conventional methods. This will open the door for completely new clinical applications of radioisotopes. The isotopic, state-selective sensitivity of the well-established technique of nuclear resonance fluorescence (NRF) will be boosted by the drastically reduced energy bandwidth (<0.1%) of the novel γ beams. Together with a much higher intensity of these beams, this will pave the road towards a γ-beam based non-invasive tomography and microscopy, assisting the management of nuclear materials, such as radioactive waste management, the detection of nuclear fissile material in the recycling process or the detection of clandestine fissile materials. Moreover, also secondary sources like low-energy, pulsed, polarized neutron beams of high intensity and high brilliance or a new type of positron source with significantly increased brilliance, for the first time fully polarized, can be realized and lead to new applications in solid state physics or material sciences. (authors)

  15. Energy-exchange collisions of dark-bright-bright vector solitons.

    Science.gov (United States)

    Radhakrishnan, R; Manikandan, N; Aravinthan, K

    2015-12-01

    We find a dark component guiding the practically interesting bright-bright vector one-soliton to two different parametric domains giving rise to different physical situations by constructing a more general form of three-component dark-bright-bright mixed vector one-soliton solution of the generalized Manakov model with nine free real parameters. Moreover our main investigation of the collision dynamics of such mixed vector solitons by constructing the multisoliton solution of the generalized Manakov model with the help of Hirota technique reveals that the dark-bright-bright vector two-soliton supports energy-exchange collision dynamics. In particular the dark component preserves its initial form and the energy-exchange collision property of the bright-bright vector two-soliton solution of the Manakov model during collision. In addition the interactions between bound state dark-bright-bright vector solitons reveal oscillations in their amplitudes. A similar kind of breathing effect was also experimentally observed in the Bose-Einstein condensates. Some possible ways are theoretically suggested not only to control this breathing effect but also to manage the beating, bouncing, jumping, and attraction effects in the collision dynamics of dark-bright-bright vector solitons. The role of multiple free parameters in our solution is examined to define polarization vector, envelope speed, envelope width, envelope amplitude, grayness, and complex modulation of our solution. It is interesting to note that the polarization vector of our mixed vector one-soliton evolves in sphere or hyperboloid depending upon the initial parametric choices. PMID:26764780

  16. Energy-exchange collisions of dark-bright-bright vector solitons

    Science.gov (United States)

    Radhakrishnan, R.; Manikandan, N.; Aravinthan, K.

    2015-12-01

    We find a dark component guiding the practically interesting bright-bright vector one-soliton to two different parametric domains giving rise to different physical situations by constructing a more general form of three-component dark-bright-bright mixed vector one-soliton solution of the generalized Manakov model with nine free real parameters. Moreover our main investigation of the collision dynamics of such mixed vector solitons by constructing the multisoliton solution of the generalized Manakov model with the help of Hirota technique reveals that the dark-bright-bright vector two-soliton supports energy-exchange collision dynamics. In particular the dark component preserves its initial form and the energy-exchange collision property of the bright-bright vector two-soliton solution of the Manakov model during collision. In addition the interactions between bound state dark-bright-bright vector solitons reveal oscillations in their amplitudes. A similar kind of breathing effect was also experimentally observed in the Bose-Einstein condensates. Some possible ways are theoretically suggested not only to control this breathing effect but also to manage the beating, bouncing, jumping, and attraction effects in the collision dynamics of dark-bright-bright vector solitons. The role of multiple free parameters in our solution is examined to define polarization vector, envelope speed, envelope width, envelope amplitude, grayness, and complex modulation of our solution. It is interesting to note that the polarization vector of our mixed vector one-soliton evolves in sphere or hyperboloid depending upon the initial parametric choices.

  17. The inhibition of fluorescence resonance energy transfer between multicolor quantum dots for rapid and sensitive detection of Staphylococcus aureus

    Science.gov (United States)

    Wang, Beibei; Wang, Qi; Ma, Meihu; Cai, Zhaoxia

    2015-01-01

    In this paper, we constructed the fluorescence resonance energy transfer (FRET) system between two multi-color quantum dots (QDs) of two sizes for rapid and sensitive detection of Staphylococcus aureus. In this system, green-emitting QDs conjugated with rabbit anti-S. aureus antibodies were used as energy donors while orange-emitting QDs conjugated with goat-anti-rabbit IgG were used as energy acceptors to form FRET system. Pre-binding of Staphylococcus aureus (S. aureus) on the donor occupied the binding sites and thus blocked resonance energy transfer between two colors QDs, leading to the quenching fluorescence of the acceptor. The fluorescence of acceptor has a linear calibration graph with the concentrations of S. aureus from 52 to 2.6 × 105 CFU mL-1. The low detection limit was 10 CFU/mL. It was worth mentioning that the detection method of S. aureus had been applied to the analysis of apple juice and milk samples, which could potentially be developed into a sensor in the further study.

  18. Fluorescent nanoparticles based on AIE fluorogens for bioimaging

    Science.gov (United States)

    Yan, Lulin; Zhang, Yan; Xu, Bin; Tian, Wenjing

    2016-01-01

    Fluorescent nanoparticles (FNPs) have recently attracted increasing attention in the biomedical field because of their unique optical properties, easy fabrication and outstanding performance in imaging. Compared with conventional molecular probes including small organic dyes and fluorescent proteins, FNPs based on aggregation-induced emission (AIE) fluorogens have shown significant advantages in tunable emission and brightness, good biocompatibility, superb photo- and physical stability, potential biodegradability and facile surface functionalization. In this review, we summarize the latest advances in the development of fluorescent nanoparticles based on AIE fluorogens including polymer nanoparticles and silica nanoparticles over the past few years, and the various biomedical applications based on these fluorescent nanoparticles are also elaborated.

  19. Spectroscopic Surface Brightness Fluctuations: Amplifying Bright Stars in Unresolved Stellar Populations

    Science.gov (United States)

    Mitzkus, M.; Dreizler, S.; Roth, M. M.

    2015-08-01

    We report on our early-stage efforts to resolve the Surface Brightness Fluctuations (SBFs) in the spectral dimension. Combining the diagnostic power of SBFs with the physical information content of spectra seems a tempting possibility to gain new insights into the bright stars in unresolved stellar populations. The new VLT integral field spectrograph MUSE is the first instrument that enables spectroscopic SBFs observationally.

  20. Observing Faint Companions Close to Bright Stars

    Science.gov (United States)

    Serabyn, Eugene

    2012-04-01

    Progress in a number of technical areas is enabling imaging and interferometric observations at both smaller angular separations from bright stars and at deeper relative contrast levels. Here we discuss recent progress in several ongoing projects at the Jet Propulsion Laboratory. First, extreme adaptive optics wavefront correction has recently enabled the use of very short (i.e., blue) wavelengths to resolve close binaries. Second, phase-based coronagraphy has recently allowed observations of faint companions to within nearly one diffraction beam width of bright stars. Finally, rotating interferometers that can observe inside the diffraction beam of single aperture telescopes are being developed to detect close-in companions and bright exozodiacal dust. This paper presents a very brief summary of the techniques involved, along with some illustrative results.

  1. High brightness semiconductor lasers with reduced filamentation

    DEFF Research Database (Denmark)

    McInerney, John; O'Brien, Peter.; Skovgaard, Peter M. W.; Houlihan, John; Mullane, Mark; O'Neill, Eamonn

    High brightness semiconductor lasers have applications in spectroscopy, fiber lasers, manufacturing and materials processing, medicine and free space communication or energy transfer. The main difficulty associated with high brightness is that, because of COD, high power requires a large aperture....... Large apertures result in high order transverse modes, filamentation and spatio-temporal instabilities, all of which degrade spatial coherence and therefore brightness. We shall describe a combined assault on three fronts: (1) minimise aperture size required for a given power by maximising the facet...... damage threshold, (2) for a given aperture, minimise self-focusing and filamentation by minimising the effective nonlinear coefficient (the alpha parameter), and (3) for a given aperture and nonlinear coefficient, develop optical cavities and propagation structures to suppress filamentation and high...

  2. High brightness semiconductor lasers with reduced filamentation

    DEFF Research Database (Denmark)

    McInerney, John; O'Brien, Peter.; Skovgaard, Peter M. W.;

    1999-01-01

    High brightness semiconductor lasers have applications in spectroscopy, fiber lasers, manufacturing and materials processing, medicine and free space communication or energy transfer. The main difficulty associated with high brightness is that, because of COD, high power requires a large aperture....... Large apertures result in high order transverse modes, filamentation and spatio-temporal instabilities, all of which degrade spatial coherence and therefore brightness. We shall describe a combined assault on three fronts: (1) minimise aperture size required for a given power by maximising the facet...... damage threshold, (2) for a given aperture, minimise self-focusing and filamentation by minimising the effective nonlinear coefficient (the alpha parameter), and (3) for a given aperture and nonlinear coefficient, develop optical cavities and propagation structures to suppress filamentation and high...

  3. Increasing the brightness of light sources

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Ling

    2006-11-16

    In this work the principle of light recycling is applied to artificial light sources in order to achieve brightness enhancement. Firstly, the feasibilities of increasing the brightness of light sources via light recycling are examined theoretically, based on the fundamental laws of thermodynamics including Kirchhoff's law on radiation, Planck's law, Lambert-Beer's law, the etendue conservation and the brightness theorem. From an experimental viewpoint, the radiation properties of three different kinds of light sources including short-arc lamps, incandescent lamps and LEDs characterized by their light-generating mechanisms are investigated. These three types of sources are used in light recycling experiments, for the purpose of 1. validating the intrinsic light recycling effect in light sources, e. g. the intrinsic light recycling effect in incandescent lamps stemming from the coiled filament structure. 2. acquiring the required parameters for establishing physical models, e.g. the emissivity/absorptivity of the short-arc lamps, the intrinsic reflectivity and the external quantum efficiency of LEDs. 3. laying the foundations for designing optics aimed at brightness enhancement according to the characteristics of the sources and applications. Based on the fundamental laws and experiments, two physical models for simulating the radiance distribution of light sources are established, one for thermal filament lamps, the other for luminescent sources, LEDs. As validation of the theoretical and experimental investigation of the light recycling effect, an optical device, the Carambola, is designed for achieving deterministic and multiple light recycling. The Carambola has the function of a concentrator. In order to achieve the maximum possible brightness enhancement with the Carambola, several combinations of sources and Carambolas are modelled in ray-tracing simulations. Sources with different light-emitting mechanisms and different radiation properties

  4. The historical investigation of cometary brightness

    Science.gov (United States)

    Hughes, David W.

    1998-12-01

    The interpretation of the way in which the brightness of a comet varied as a function of both its heliocentric and geocentric distance was essentially started by Isaac Newton in his book Philosophiae Naturalis Principia Mathematica, published in 1687. Astronomers have argued about the form of this variability ever since, and for many years it was regarded as an important clue as to the physical nature of the cometary nucleus and its decay process. This paper reviews our understanding of the causes of cometary brightness variability between about 1680 and the 1950s.

  5. The environment of Low Surface Brightness Galaxies

    OpenAIRE

    Rosenbaum, S. D.; Bomans, D. J.

    2004-01-01

    Using the Early Data Release of the Sloan Digital Sky Survey (SDSS) we investigated the clustering properties of Low Surface Brightness (LSB) galaxies in comparison to normal, High Surface Brightness (HSB) galaxies. We selected LSB galaxies and HSB galaxies with well measured redshifts from the SDSS data base and performed three-dimensional neighbour counting analysis within spheres of radii between 0.8 Mpc and 8.0 Mpc. As a second analysis method we used an N-th neighbour analysis with N var...

  6. Discovery program for bright quasars: preliminary results

    International Nuclear Information System (INIS)

    A program has been undertaken to obtain a complete sample of bright quasars on the basis of ultraviolet color excess. Spectroscopic examination of candidates selected from two-color Schmidt telescope films has yielded four new quasars brighter than B = 16/sup m/5, with the candidate list containing two more previously identified. Magnitudes, color indices, and redshifts are presented for the new discoveries, along with positions and finding charts. Although the sample is not yet complete, these first results suggest that bright quasars have a low surface density

  7. A Magnetic Bright Point Case Study

    Czech Academy of Sciences Publication Activity Database

    Utz, D.; Jurčák, Jan; Bellot Rubio, L.; del Toro Iniesta, J.C.; Thonhofer, S.; Hanslmeier, A.; Veronig, A.; Muller, R.; Lemmerer, B.

    2013-01-01

    Roč. 37, č. 2 (2013), s. 459-470. ISSN 1845-8319. [Hvar Astrophysical Colloquium /12./. Hvar, 03.09.2012-07.09.2012] R&D Projects: GA MŠk(CZ) MEB061109 Institutional support: RVO:67985815 Keywords : solar magnetic field * magnetic bright points * sunrise/IMaX Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  8. A photometric investigation of a bright Geminid

    NARCIS (Netherlands)

    Degewij, J.; Diggelen, Johannes van

    1968-01-01

    Photographic observations of meteors in the Netherlands started with a bright Geminid of photographic magnitude −8 observed on December 11, 1955, 21h39m55s by M. Alberts. From the assumed radiant and velocity we have constructed the trajectory of the bolide. The luminosity of the trail has been dete

  9. Brightness versus roughness: a multiscale approach

    International Nuclear Information System (INIS)

    A link between roughness and brightness is sought for brass specimens that were superfinished, sandblasted and brushed. Only the blasting conditions are varied in order to get different roughness and brightness. First, a relation between roughness and brightness is sought for specimens that were superfinished and sandblasted. The best relation is obtained using the mean height of the motifs, calculated using a low-pass filter and cut-off length equal to 30 μm, with a logarithmic–logarithmic model. Then, the same type of relation is determined after superfinishing sandblasting and brushing. The core material volume Vmc, computed using a high-pass filter with a cut-off length of 60 μm and a linear–logarithmic relationship, gives the best results. A relation between roughness and brightness that is common to both the pre-brushing state and post-brushing state is identified: the best roughness parameter is the arithmetic mean deviation Sa using a high-pass filter with a cut-off of 15 μm, with a logarithmic–logarithmic relationship. Finally, it is shown that the use of these filtering conditions enables us to verify the model of Beckmann and Spizzichino for the examined specimens. This scale corresponds to the end of the fractal regime and is close to the end of the signal correlation. (paper)

  10. Discussion of high brightness rf linear accelerators

    International Nuclear Information System (INIS)

    The fundamental aspects of high-brightness rf linacs are outlined, showing the breadth and complexity of the technology and indicating that synergism with advancements in other areas is important. Areas of technology reviewed include ion sources, injectors, rf accelerator structures, beam dynamics, rf power, and automatic control

  11. Circadian Phase-Shifting Effects of Bright Light, Exercise, and Bright Light + Exercise

    OpenAIRE

    Youngstedt, Shawn D.; Kline, Christopher E.; Elliott, Jeffrey A; Zielinski, Mark; Devlin, Tina M.; Moore, Teresa A.

    2016-01-01

    Limited research has compared the circadian phase-shifting effects of bright light and exercise and additive effects of these stimuli. The aim of this study was to compare the phase-delaying effects of late night bright light, late night exercise, and late evening bright light followed by early morning exercise. In a within-subjects, counterbalanced design, 6 young adults completed each of three 2.5-day protocols. Participants followed a 3-h ultra-short sleep-wake cycle, involving wakefulness...

  12. Conservation of an ion beam brightness. Study of a non brightness disturbing lens

    International Nuclear Information System (INIS)

    Experimental studies of ion sources prove that large initial brightnesses can be obtained by using the plasma expansion principle. However these brightnesses are usually spoiled by the beam focusing and accelerating systems. A high intensity focusing set up is first theoretically studied, then numerically determined by use of a 7094 IBM computer. Aberrations have been minimized. It has then been possible to construct a set up conserving the source initial brightness. For a 100 mA beam the focusing voltage is 150 kV, the beam study has been done for 350 keV beam final energy. Given is a discussion of results. (author)

  13. Fabrication of bright and small size semiconducting polymer nanoparticles for cellular labelling and single particle tracking

    Science.gov (United States)

    Wei, Lin; Zhou, Peng; Yang, Qingxiu; Yang, Qiaoyu; Ma, Ming; Chen, Bo; Xiao, Lehui

    2014-09-01

    In this work, we demonstrate a convenient and robust strategy for efficient fabrication of high fluorescence quantum yield (QY, 49.8 +/- 3%) semiconducting polymer nanoparticles (SPNs), with size comparable with semiconductor quantum dots (Qdots). The SPNs were synthesized by co-precipitation of hydrophobic semiconducting polymer together with amphiphilic multidentate polymer. Comprehensive spectroscopic and microscopic characterizations showed that the SPNs possess superior photophysical performance, with excellent fluorescence brightness and reduced photoblinking in contrast with Qdots, as well as good photostability compared to a fluorescent protein of a similar size, phycoerythrin. More importantly, by conjugating membrane biomarkers onto the surface of SPNs, it was found that they were not only suitable for specific cellular labelling but also for single particle tracking because of the improved optical performance.In this work, we demonstrate a convenient and robust strategy for efficient fabrication of high fluorescence quantum yield (QY, 49.8 +/- 3%) semiconducting polymer nanoparticles (SPNs), with size comparable with semiconductor quantum dots (Qdots). The SPNs were synthesized by co-precipitation of hydrophobic semiconducting polymer together with amphiphilic multidentate polymer. Comprehensive spectroscopic and microscopic characterizations showed that the SPNs possess superior photophysical performance, with excellent fluorescence brightness and reduced photoblinking in contrast with Qdots, as well as good photostability compared to a fluorescent protein of a similar size, phycoerythrin. More importantly, by conjugating membrane biomarkers onto the surface of SPNs, it was found that they were not only suitable for specific cellular labelling but also for single particle tracking because of the improved optical performance. Electronic supplementary information (ESI) available: Experimental section and additional supporting results as noted in the text

  14. Synthesis and fluorescent properties of poly(arylpyrazoline)'s for organic-electronics

    Science.gov (United States)

    Vandana, T.; Ramkumar, V.; Kannan, P.

    2016-08-01

    The present work focuses on the synthesis and characterization of poly(arylchalcone)'s (PCH I-IV) by reacting acetone with various dialdehydes for the first time at below ambient temperature followed by cyclization with phenylhydrazinehydrochloride to yield luminescent poly(arylpyrazoline)'s (PPY I-IV). The synthesized polymers were characterized by standard techniques such as, GPC, SEM, TGA, FT-IR, 1H NMR, UV-Vis absorption and fluorescence spectroscopy, and electrochemical studies by cyclic voltammetry analyses. The Pyrazoline group hooked with different aryl donors such as benzene, thiophene, carbazole, triphenylamine, thus results a series of blue and green emitting materials. The obtained optical bandgap energy of the polymers (PPY I-IV) were 2.53, 3.41, 3.07, 3.10 eV respectively, suggest that all the polymers belongs to semiconducting category. The solvent effect of polymers was thoroughly studied and explained by Lippert-Mataga equation. The polymers I & IV display large degree of intra-molecular charge transfer in excited state evidenced from solvatochromic shift on the emission spectra. The obtained results demonstrate that they are promising materials for organic electronics applications.

  15. Fluorescent polystyrene photonic crystals self-assembled with water-soluble conjugated polyrotaxanes

    Directory of Open Access Journals (Sweden)

    Francesco Di Stasio

    2013-10-01

    Full Text Available We demonstrate control of the photoluminescence spectra and decay rates of water-soluble green-emitting conjugated polyrotaxanes by incorporating them in polystyrene opals with a stop-band spectrally tuned on the rotaxane emission (405–650 nm. We observe a suppression of the luminescence within the photonic stop-band and a corresponding enhancement of the high-energy edge (405–447 nm. Time-resolved measurements reveal a wavelength-dependent modification of the emission lifetime, which is shortened at the high-energy edge (by ∼11%, in the range 405–447 nm, but elongated within the stop-band (by ∼13%, in the range 448–482 nm. We assign both effects to the modification of the density of photonic states induced by the photonic crystal band structure. We propose the growth of fluorescent composite photonic crystals from blends of “solvent-compatible” non-covalently bonded nanosphere-polymer systems as a general method for achieving a uniform distribution of polymeric dopants in three-dimensional self-assembling photonic structures.

  16. Membrane Permeable Esterase–Activated Fluorescent Imaging Probe

    OpenAIRE

    Kim, Youngmi; Choi, Yongdoo; Weissleder, Ralph; Tung, Ching-Hsuan

    2007-01-01

    An esterase-triggered probe 2 derived from a cyanine-based pH sensitive dye was developed for cell labeling. Permeation of probe 2 into cells and subsequent hydrolytic activation by cellular esterases result in a bright fluorescent intracellular signal.

  17. Circadian Phase-Shifting Effects of Bright Light, Exercise, and Bright Light + Exercise.

    Science.gov (United States)

    Youngstedt, Shawn D; Kline, Christopher E; Elliott, Jeffrey A; Zielinski, Mark R; Devlin, Tina M; Moore, Teresa A

    2016-01-01

    Limited research has compared the circadian phase-shifting effects of bright light and exercise and additive effects of these stimuli. The aim of this study was to compare the phase-delaying effects of late night bright light, late night exercise, and late evening bright light followed by early morning exercise. In a within-subjects, counterbalanced design, 6 young adults completed each of three 2.5-day protocols. Participants followed a 3-h ultra-short sleep-wake cycle, involving wakefulness in dim light for 2h, followed by attempted sleep in darkness for 1 h, repeated throughout each protocol. On night 2 of each protocol, participants received either (1) bright light alone (5,000 lux) from 2210-2340 h, (2) treadmill exercise alone from 2210-2340 h, or (3) bright light (2210-2340 h) followed by exercise from 0410-0540 h. Urine was collected every 90 min. Shifts in the 6-sulphatoxymelatonin (aMT6s) cosine acrophase from baseline to post-treatment were compared between treatments. Analyses revealed a significant additive phase-delaying effect of bright light + exercise (80.8 ± 11.6 [SD] min) compared with exercise alone (47.3 ± 21.6 min), and a similar phase delay following bright light alone (56.6 ± 15.2 min) and exercise alone administered for the same duration and at the same time of night. Thus, the data suggest that late night bright light followed by early morning exercise can have an additive circadian phase-shifting effect. PMID:27103935

  18. Fluorescent probe based on heteroatom containing styrylcyanine: pH-sensitive properties and bioimaging in vivo

    International Nuclear Information System (INIS)

    A novel fluorescent probe based on heteroatom containing styrylcyanine is synthesized. The fluorescence of probe is bright green in basic and neutral media but dark orange in strong acidic environments, which could be reversibly switched. Such behavior enables it to work as a fluorescent pH sensor in the solution state and a chemosensor for detecting acidic and basic volatile organic compounds. Analyses by NMR spectroscopy confirm that the protonation or deprotonation of pyridinyl moiety is responsible for the sensing process. In addition, the fluorescent microscopic images of probe in live cells and zebrafish are achieved successfully, suggesting that the probe has good cell membrane permeability and low cytotoxicity. - Graphical abstract: A novel styrylcyanine-based fluorescent pH probe was designed and synthesized, the fluorescence of which is bright green in basic and neutral media but dark orange in strong acidic environments. Such behavior enables it to work as a fluorescent pH sensor in solution states, and a chemosensor for detecting volatile organic compounds with high acidity and basicity in solid state. In addition, it can be used for fluorescent imaging in living cell and living organism. - Highlights: • Bright green fluorescence was observed in basic and neutral media. • Dark orange fluorescence was found in strong acidic environments. • Volatile organic compounds with high acidity and basicity could be detected. • Bioimaging in living cell and living organism was achieved successfully

  19. Fluorescent probe based on heteroatom containing styrylcyanine: pH-sensitive properties and bioimaging in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xiaodong [School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640 (China); Gao, Ya; Huang, Zhibing; Chen, Xiaohui; Ke, Zhiyong [School of Basic Medical Science, Southern Medical University, Guangzhou 510515 (China); Zhao, Peiliang; Yan, Yichen [Department of Organic Pharmaceutical Chemistry, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515 (China); Liu, Ruiyuan, E-mail: ruiyliu@smu.edu.cn [Department of Organic Pharmaceutical Chemistry, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515 (China); Qu, Jinqing, E-mail: cejqqu@scut.edu.cn [School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640 (China)

    2015-07-01

    A novel fluorescent probe based on heteroatom containing styrylcyanine is synthesized. The fluorescence of probe is bright green in basic and neutral media but dark orange in strong acidic environments, which could be reversibly switched. Such behavior enables it to work as a fluorescent pH sensor in the solution state and a chemosensor for detecting acidic and basic volatile organic compounds. Analyses by NMR spectroscopy confirm that the protonation or deprotonation of pyridinyl moiety is responsible for the sensing process. In addition, the fluorescent microscopic images of probe in live cells and zebrafish are achieved successfully, suggesting that the probe has good cell membrane permeability and low cytotoxicity. - Graphical abstract: A novel styrylcyanine-based fluorescent pH probe was designed and synthesized, the fluorescence of which is bright green in basic and neutral media but dark orange in strong acidic environments. Such behavior enables it to work as a fluorescent pH sensor in solution states, and a chemosensor for detecting volatile organic compounds with high acidity and basicity in solid state. In addition, it can be used for fluorescent imaging in living cell and living organism. - Highlights: • Bright green fluorescence was observed in basic and neutral media. • Dark orange fluorescence was found in strong acidic environments. • Volatile organic compounds with high acidity and basicity could be detected. • Bioimaging in living cell and living organism was achieved successfully.

  20. Expression-Enhanced Fluorescent Proteins Based on Enhanced Green Fluorescent Protein for Super-resolution Microscopy.

    Science.gov (United States)

    Duwé, Sam; De Zitter, Elke; Gielen, Vincent; Moeyaert, Benjamien; Vandenberg, Wim; Grotjohann, Tim; Clays, Koen; Jakobs, Stefan; Van Meervelt, Luc; Dedecker, Peter

    2015-10-27

    "Smart fluorophores", such as reversibly switchable fluorescent proteins, are crucial for advanced fluorescence imaging. However, only a limited number of such labels is available, and many display reduced biological performance compared to more classical variants. We present the development of robustly photoswitchable variants of enhanced green fluorescent protein (EGFP), named rsGreens, that display up to 30-fold higher fluorescence in E. coli colonies grown at 37 °C and more than 4-fold higher fluorescence when expressed in HEK293T cells compared to their ancestor protein rsEGFP. This enhancement is not due to an intrinsic increase in the fluorescence brightness of the probes, but rather due to enhanced expression levels that allow many more probe molecules to be functional at any given time. We developed rsGreens displaying a range of photoswitching kinetics and show how these can be used for multimodal diffraction-unlimited fluorescence imaging such as pcSOFI and RESOLFT, achieving a spatial resolution of ∼70 nm. By determining the first ever crystal structures of a negative reversibly switchable FP derived from Aequorea victoria in both the "on"- and "off"-conformation we were able to confirm the presence of a cis-trans isomerization and provide further insights into the mechanisms underlying the photochromism. Our work demonstrates that genetically encoded "smart fluorophores" can be readily optimized for biological performance and provides a practical strategy for developing maturation- and stability-enhanced photochromic fluorescent proteins. PMID:26308583

  1. Intracellular cascade FRET for temperature imaging of living cells with polymeric ratiometric fluorescent thermometers.

    Science.gov (United States)

    Hu, Xianglong; Li, Yang; Liu, Tao; Zhang, Guoying; Liu, Shiyong

    2015-07-22

    Intracellular temperature plays a prominent role in cellular functions and biochemical activities inside living cells, but effective intracellular temperature sensing and imaging is still in its infancy. Herein, thermoresponsive double hydrophilic block copolymers (DHBCs)-based fluorescent thermometers were fabricated to investigate their application in intracellular temperature imaging. Blue-emitting coumarin monomer, CMA, green-emitting 7-nitro-2,1,3-benzoxadiazole (NBD) monomer, NBDAE, and red-emitting rhodamine B monomer, RhBEA, were copolymerized separately with N-isopropylacrylamide (NIPAM) to afford dye-labeled PEG-b-P(NIPAM-co-CMA), PEG-b-P(NIPAM-co-NBDAE), and PEG-b-P(NIPAM-co-RhBEA). Because of the favorable fluorescence resonance energy transfer (FRET) potentials between CMA and NBDAE, NBDAE and RhBEA, as well as the slight tendency between CMA and RhBEA fluorophore pairs, three polymeric thermometers based on traditional one-step FRET were fabricated by facile mixing two of these three fluorescent DHBCs, whereas exhibiting limited advantages. Thus, two-step cascade FRET among three polymeric fluorophores was further interrogated, in which NBD acted as a bridging dye by transferring energy from CMA to RhBEA. Through the delicate optimization of the molar contents of three polymeric components, a ∼8.4-fold ratio change occurred in the temperature range of 20-44 °C, and the detection sensitivity improved significantly, reached as low as ∼0.4 °C, which definitely outperformed other one-step FRET thermometers in the intracellular temperature imaging of living cells. To our knowledge, this work represents the first example of polymeric ratiometric thermometer employing thermoresponsive polymer-based cascade FRET mechanism. PMID:26114380

  2. The bright optical flash from GRB 060117

    CERN Document Server

    Jel'inek, M; Kubánek, P; Hudec, R; Nekola, M; Grygar, J; Castro-Tirado, A J; Gorosabel, J; Hrabovsk'y, M; Mandat, D; Nosek, D; Palatka, M; Pandey, S B; Pech, M; Schovanek, P; De Postigo, A U; Vítek, S; Jel\\'inek, Martin; Prouza, Michael; Kub\\'anek, Petr; Hudec, Ren\\'e; Nekola, Martin; R}\\'idk\\'y, Jan {; Grygar, Ji{r}\\'i; Castro-Tirado, Alberto J.; Gorosabel, Javier; Hrabovsk\\'y, Miroslav; Mand\\'at, Du{s}an; Nosek, Dalibor; Palatka, Miroslav; Pandey, Shashi B.; Pech, Miroslav; Schov\\'anek, Petr; S}m\\'ida, Radom\\'ir {; Postigo, Antonio de Ugarte; V\\'itek, Stanislav

    2006-01-01

    We present a discovery and observation of an extraordinarily bright prompt optical emission of the GRB 060117 obtained by a wide-field camera atop the robotic telescope FRAM of the Pierre Auger Observatory from 2 to 10 minutes after the GRB. We found rapid average temporal flux decay of alpha = -1.7 +- 0.1 and a peak brightness R = 10.1 mag. Later observations by other instruments set a strong limit on the optical and radio transient fluxes, unveiling an unexpectedly rapid further decay. We present an interpretation featuring a relatively steep electron-distribution parameter p ~ 3.0 and providing a straightforward solution for the overall fast decay of this optical transient as a transition between reverse and forward shock.

  3. An ultra-bright atom laser

    International Nuclear Information System (INIS)

    We present a novel, ultra-bright atom laser and an ultra-cold thermal atom beam. Using rf-radiation we strongly couple the magnetic hyperfine levels of 87Rb atoms in a trapped Bose–Einstein condensate. The resulting time-dependent adiabatic potential forms a trap, which at low rf-frequencies opens just below the condensate and thus allows an extremely bright well-collimated atom laser beam to emerge. As opposed to traditional atom lasers based on weak coupling of the magnetic hyperfine levels, this technique allows us to outcouple atoms at an arbitrarily large rate. We achieve a flux of 4×107 atom s-1, a seven fold increase compared to the brightest atom lasers to date. Furthermore, we demonstrate by two orders of magnitude the coldest thermal atom beam (200 nK). (paper)

  4. Quantum Bright Soliton in a Disorder Potential

    Science.gov (United States)

    Sacha, K.; Delande, D.; Zakrzewski, J.

    2009-11-01

    At very low temperature, a quasi-one-dimensional ensemble of atoms with attractive interactions tend to form a bright soliton. When exposed to a sufficiently weak external potential, the shape of the soliton is not modified, but its external motion is affected. We develop in detail the Bogoliubov approach for the problem, treating, in a non-perturbative way, the motion of the center of mass of the soliton. Quantization of this motion allows us to discuss its long time properties. In particular, in the presence of a disordered potential, the quantum motion of the center of mass of a bright soliton may exhibit Anderson localization, on a localization length which may be much larger than the soliton size and could be observed experimentally.

  5. Simultaneous detection of pathogenic bacteria using an aptamer based biosensor and dual fluorescence resonance energy transfer from quantum dots to carbon nanoparticles

    International Nuclear Information System (INIS)

    We report on a method for simultaneous detection of the pathogens Vibrio parahaemolyticus and Salmonella typhimurium. It is based on dual fluorescence resonance energy transfer (FRET) from green-emitting quantum-dots (gQDs) and red-emitting quantum-dots (rQDs) as donors, and on novel amorphous carbon nanoparticles (CNPs) that act as acceptor. The gQDs were modified with an aptamer (Apt 1) recognizing V. parahaemolyticus, and the rQDs with an aptamer (Apt 2) recognizing S. typhimurium. The fluorescence of both QDs is strongly quenched in the presence of CNPs. However, on addition of the target analytes, the QDs-aptamer-target complex is formed and quenching by CNPs is suppressed. The fluorescence of the QDs is linearly proportional to the concentration of the two pathogens in the range from 50 to 106 cfu·mL−1, with detection limits as low as 25 cfu·mL−1 for V. parahaemolyticus, and of 35 cfu·mL−1 for S. typhimurium. The assay was applied to real food samples, and the results were consistent with the results obtained with plate counting methods. We presume that this strategy can be extended to the detection of other pathogenic bacteria and biomolecules by simply substituting the aptamer. (author)

  6. Modular Zero Energy. BrightBuilt Home

    Energy Technology Data Exchange (ETDEWEB)

    Aldrich, Robb [Steven Winter Associates, Inc., Norwalk, CT (United States); Butterfield, Karla [Steven Winter Associates, Inc., Norwalk, CT (United States)

    2016-03-01

    With funding from the Building America Program, part of the U.S. Department of Energy Building Technologies Office, the Consortium for Advanced Residential Buildings (CARB) worked with BrightBuilt Home (BBH) to evaluate and optimize building systems. CARB’s work focused on a home built by Black Bros. Builders in Lincolnville, Maine (International Energy Conservation Code Climate Zone 6). As with most BBH projects to date, modular boxes were built by Keiser Homes in Oxford, Maine.

  7. Spectral Characterization of Bright Materials on Vesta

    Science.gov (United States)

    Capaccioni, Fabrizio; DeSanctis, M. C.; Ammannito, E.; Li, Jian-Yang; Longobardo, A.; Mittlefehldt, David W.; Palomba, E.; Pieters, C. M.; Schroeder, S. E.; Tosi, F.; Hiesinger, H.; Blewett, D. T.; Russell, C. T.; Raymond, C. A.

    2012-01-01

    The surface of Vesta, as observed by the camera and imaging spectrometer onboard the Dawn spacecraft, displays large surface diversity in terms of its geology and mineralogy with noticeably dark and bright areas on the surface often associated with various geological features and showing remarkably different forms. Here we report our initial attempt to spectrally characterize the areas that are distinctively brighter than their surroundings.

  8. Surface Brightness Fluctuations as Stellar Population Indicators

    OpenAIRE

    Blakeslee, John P

    2009-01-01

    Surface Brightness Fluctuations (SBF) can provide useful information about the unresolved stellar content of early-type galaxies and spiral bulges. The absolute SBF magnitude Mbar in a given passband depends on the properties of the stellar population and can be predicted by population synthesis models. SBF measurements in different bandpasses are sensitive to different evolutionary stages within the galaxy stellar population. Near-IR SBF magnitudes are sensitive to the evolution of stars wit...

  9. Bright vortex solitons in Bose Condensates

    OpenAIRE

    Adhikari, Sadhan K.

    2003-01-01

    We suggest the possibility of observing and studying bright vortex solitons in attractive Bose-Einstein condensates in three dimensions with a radial trap. Such systems lie on the verge of critical stability and we discuss the conditions of their stability. We study the interaction between two such solitons. Unlike the text-book solitons in one dimension, the interaction between two radially trapped and axially free three-dimensional solitons is inelastic in nature and involves exchange of pa...

  10. Bright Solitary Waves in Malignant Gliomas

    OpenAIRE

    Pérez-García, Víctor M.; Calvo, Gabriel F.; Belmonte-Beitia, Juan; Diego, D.; Pérez-Romasanta, Luis

    2011-01-01

    We put forward a nonlinear wave model describing the fundamental physio-pathologic features of an aggressive type of brain tumors: glioblastomas. Our model accounts for the invasion of normal tissue by a proliferating and propagating rim of active glioma cancer cells in the tumor boundary and the subsequent formation of a necrotic core. By resorting to numerical simulations, phase space analysis and exact solutions, we prove that bright solitary tumor waves develop in such systems.

  11. Origin of bright flares in SFXTs

    CERN Document Server

    Postnov, K; Sidoli, L; Paizis, A

    2014-01-01

    In the settling accretion theory, which is applicable to quasi-spherical accreting slowly rotating magnetized neutron stars with X-ray luminosity $L_x\\lesssim 4\\times 10^{36}$~erg/s, bright X-ray flares ($\\sim 10^{38}-10^{40}$~ergs) observed in supergiant fast X-ray transients (SFXT) may be produced by sporadic capture of magnetized stellar-wind plasma from the early-type supergiant. At sufficiently low steady accretion rates ($\\lesssim 10^{15}$~g/s) through the shell around the neutron star magnetosphere at the settling accretion stage, magnetic reconnection can temporarily enhance the magnetospheric plasma entry rate, resulting in copious production of X-ray photons, strong Compton cooling, and ultimately in unstable accretion of the entire shell. A bright flare develops on the free-fall time scale in the shell, $R_B^{3/2}/\\sqrt{GM}\\sim 10^3-10^4$~s ($R_B$ is the classical Bondi capture radius), and the typical energy released in an SFXT bright flare corresponds to the mass of the shell.

  12. On the origin of facular brightness

    CERN Document Server

    Kostik, R

    2016-01-01

    This paper studies the dependence of the CaIIH line core brightness on the strength and inclination of photospheric magnetic field, and on the parameters of convective and wave motions in a facular region at the solar disc center. We use three simultaneous datasets obtained at the German Vacuum Tower Telescope (Observatorio del Teide, Tenerife): (1) spectra of BaII 4554 A line registered with the instrument TESOS to measure the variations of intensity and velocity through the photosphere up to the temperature minimum; (2) spectropolarimetric data in FeI 1.56 $\\mu$m lines (registered with the instrument TIP II) to measure photospheric magnetic fields; (3) filtergrams in CaIIH that give information about brightness fluctuations in the chromosphere. The results show that the CaIIH brightness in the facula strongly depends on the power of waves with periods in the 5-min range, that propagate upwards, and also on the phase shift between velocity oscillations at the bottom photosphere and around the temperature min...

  13. Search for bright stars with infrared excess

    International Nuclear Information System (INIS)

    Bright stars, stars with visual magnitude smaller than 6.5, can be studied using small telescope. In general, if stars are assumed as black body radiator, then the color in infrared (IR) region is usually equal to zero. Infrared data from IRAS observations at 12 and 25μm (micron) with good flux quality are used to search for bright stars (from Bright Stars Catalogues) with infrared excess. In magnitude scale, stars with IR excess is defined as stars with IR color m12−m25>0; where m12−m25 = −2.5log(F12/F25)+1.56, where F12 and F25 are flux density in Jansky at 12 and 25μm, respectively. Stars with similar spectral type are expected to have similar color. The existence of infrared excess in the same spectral type indicates the existence of circum-stellar dust, the origin of which is probably due to the remnant of pre main-sequence evolution during star formation or post AGB evolution or due to physical process such as the rotation of those stars

  14. Bright-field Nanoscopy: Visualizing Nano-structures with Localized Optical Contrast Using a Conventional Microscope

    CERN Document Server

    Suran, Swathi; Raghavan, Srinivasan; Varma, Manoj M

    2015-01-01

    Most methods for optical visualization beyond the diffraction limit rely on fluorescence emission by molecular tags. Here, we report a method for visualization of nanostructures down to a few nanometers using a conventional bright-field microscope without requiring additional molecular tags such as fluorophores. The technique, Bright-field Nanoscopy, is based on the strong thickness dependent color of ultra-thin germanium on an optically thick gold film. We demonstrate the visualization of grain boundaries in chemical vapour deposited single layer graphene and the detection of single 40 nm Ag nanoparticles. We estimate a size detection limit of about 2 nm using this technique. In addition to visualizing nano-structures, this technique can be used to probe fluid phenomena at the nanoscale, such as transport through 2D membranes. We estimated the water transport rate through a 1 nm thick polymer film using this technique, as an illustration. Further, the technique can also be extended to study the transport of ...

  15. The surface brightness of spiral galaxies: Pt. 4

    International Nuclear Information System (INIS)

    Using measurements from IRAS correlations are found between optical surface brightness and both infrared-to-optical flux ratio and infrared colour temperature, in the sense that galaxies with high surface brightness have higher FIR emission and higher temperatures. (author)

  16. Fluorescence detection: SPIE volume 743

    International Nuclear Information System (INIS)

    This book contains proceedings arranged into four sessions. They are: Fluorescence spectroscopic techniques; Fluorescence in analysis and materials characterization; Fluorescence in medicine and biochemistry; and Fluorescence in criminalistics

  17. Fluorescence detection: SPIE volume 743

    Energy Technology Data Exchange (ETDEWEB)

    Menzel, E.R.

    1987-01-01

    This book contains proceedings arranged into four sessions. They are: Fluorescence spectroscopic techniques; Fluorescence in analysis and materials characterization; Fluorescence in medicine and biochemistry; and Fluorescence in criminalistics.

  18. Star formation and the surface brightness of spiral galaxies

    International Nuclear Information System (INIS)

    The (blue) surface brightness of spiral galaxies is significantly correlated with their Hα linewidth. This can be most plausibly interpreted as a correlation of surface brightness with star formation rate. There is also a significant difference in surface brightness between galaxies forming stars in a grand design spiral pattern and those with floc star formation regions. (author)

  19. Controlling excitons. Concepts for phosphorescent organic LEDs at high brightness

    Energy Technology Data Exchange (ETDEWEB)

    Reineke, Sebastian

    2009-11-15

    This work focusses on the high brightness performance of phosphorescent organic light-emitting diodes (OLEDs). The use of phosphorescent emitter molecules in OLEDs is essential to realize internal electron-photon conversion efficiencies of 100 %. However, due to their molecular nature, the excited triplet states have orders of magnitude longer time constants compared to their fluorescent counterparts which, in turn, strongly increases the probability of bimolecular annihilation. As a consequence, the efficiencies of phosphorescent OLEDs decline at high brightness - an effect known as efficiency roll-off, for which it has been shown to be dominated by triplet-triplet annihilation (TTA). In this work, TTA of the archetype phosphorescent emitter Ir(ppy){sub 3} is investigated in time-resolved photoluminescence experiments. For the widely used mixed system CBP:Ir(ppy){sub 3}, host-guest TTA - an additional unwanted TTA channel - is experimentally observed at high excitation levels. By using matrix materials with higher triplet energies, this effect is efficiently suppressed, however further studies show that the efficiency roll-off of Ir(ppy)3 is much more pronounced than predicted by a model based on Foerster-type energy transfer, which marks the intrinsic limit for TTA. These results suggest that the emitter molecules show a strong tendency to form aggregates in the mixed film as the origin for enhanced TTA. Transmission electron microscopy images of Ir(ppy){sub 3} doped mixed films give direct proof of emitter aggregates. Based on these results, two concepts are developed that improve the high brightness performance of OLEDs. In a first approach, thin intrinsic matrix interlayers are incorporated in the emission layer leading to a one-dimensional exciton confinement that suppresses exciton migration and, consequently, TTA. The second concept reduces the efficiency roll-off by using an emitter molecule with slightly different chemical structure, i.e. Ir(ppy){sub 2

  20. Synthesis of BODIPY derivatives substituted with various bioconjugatable linker groups: a construction kit for fluorescent labeling of receptor ligands.

    Science.gov (United States)

    Heisig, Fabian; Gollos, Sabrina; Freudenthal, Sven J; El-Tayeb, Ali; Iqbal, Jamshed; Müller, Christa E

    2014-01-01

    The goal of the present study was to design small, functionalized green-emitting BODIPY dyes, which can readily be coupled to target molecules such as receptor ligands, or even be integrated into their pharmacophores. A simple two-step one-pot procedure starting from 2,4-dimethylpyrrole and ω-bromoalkylcarboxylic acid chlorides was used to obtain new ω-bromoalkyl-substituted BODIPY fluorophores (1a-1f) connected via alkyl spacers of different length to the 8-position of the fluorescent dye. The addition of radical inhibitors reduced the amount of side products. The ω-bromoalkyl-substituted BODIPYs were further converted to introduce various functional groups: iodo-substituted dyes were obtained by Finkelstein reaction in excellent yields; microwave-assisted reaction with methanolic ammonia led to fast and clean conversion to the amino-substituted dyes; a hydroxyl-substituted derivative was prepared by reaction with sodium ethylate, and thiol-substituted BODIPYs were obtained by reaction of 1a-1f with potassium thioacetate followed by alkaline cleavage of the thioesters. Water-soluble derivatives were prepared by introducing sulfonate groups into the 2- and 6-position of the BODIPY core. The synthesized BODIPY derivatives showed high fluorescent yields and appeared to be stable under basic, reducing and oxidative conditions. As a proof of concept, 2-thioadenosine was alkylated with bromoethyl-BODIPY 1b. The resulting fluorescent 2-substituted adenosine derivative 15 displayed selectivity for the A3 adenosine receptor (ARs) over the other AR subtypes, showed agonistic activity, and may thus become a useful tool for studying A3ARs, or a lead structure for further optimization. The new functionalized dyes may be widely used for fluorescent labeling allowing the investigation of biological targets and processes. PMID:24052460

  1. Monitoring of bright blazars with MAGIC telescope

    OpenAIRE

    Hsu, C. C.; Satalecka, K.; Thom, M; Backes, M.; Bernardini, E.; Bonnoli, G.; Galante, N.; Goebel, F; Lindfors, E.; Majumdar, P.; Stamerra, A.; Wagner, R. M.

    2009-01-01

    Blazars, a class of Active Galactic Nuclei (AGN) characterized by a close orientation of their relativistic outflows (jets) towards the line of sight, are a well established extragalactic TeV $\\gamma$-ray emitters. Since 2006, three nearby and TeV bright blazars, Markarian (Mrk) 421, Mrk 501 and 1ES 1959+650, are regularly observed by the MAGIC telescope with single exposures of 30 to 60 minutes. The sensitivity of MAGIC allows to establish a flux level of 30% of the Crab flux for each such o...

  2. The Bright Quasar 3C 273

    OpenAIRE

    Courvoisier, Thierry J. -L.

    1998-01-01

    We review the observed properties of the bright quasar 3C~273 and discuss the implications of these observations for the emission processes and in view of gaining a more global understanding of the object. Continuum and line emission are discussed. The emission from the radio domain to gamma rays are reviewed. Emphasis is given to variability studies across the spectrum as a means to gain some understanding on the relationships between the emission components. 3C~273 has a small scale jet and...

  3. Quantum bright soliton in a disorder potential

    OpenAIRE

    Sacha, K.; Delande, D; Zakrzewski, J.

    2009-01-01

    At very low temperature, a quasi-one-dimensional ensemble of atoms with attractive interactions tend to form a bright soliton. When exposed to a sufficiently weak external potential, the shape of the soliton is not modified, but its external motion is affected. We develop in detail the Bogoliubov approach for the problem, treating, in a non-perturbative way, the motion of the center of mass of the soliton. Quantization of this motion allows us to discuss its long time properties. In particula...

  4. Extremely High Brightness from Polymer-Encapsulated Quantum Dots for Two-photon Cellular and Deep-tissue Imaging

    OpenAIRE

    Fan, Yanyan; Liu, Helin; Han, Rongcheng; Huang, Lu; Shi, Hao; Sha, Yinlin; Jiang, Yuqiang

    2015-01-01

    Materials possessing high two photon absorption (TPA) are highly desirable for a range of fields, such as three-dimensional data storage, TP microscopy (TPM) and photodynamic therapy (PDT). Specifically, for TPM, high TP excitation (TPE) brightness (σ × ϕ, where σ is TPA cross-sections and ϕ is fluorescence quantum yield), excellent photostability and minimal cytotoxicity are highly desirable. However, when TPA materials are transferred to aqueous media through molecule engineering or nanopar...

  5. Selection effects in the bivariate brightness distribution for spiral galaxies

    International Nuclear Information System (INIS)

    The joint distribution of total luminosity and characteristic surface brightness (the bivariate brightness distribution) is investigated for a complete sample of spiral galaxies in the Virgo cluster. The influence of selection and physical limits of various kinds on the apparent distribution are detailed. While the distribution of surface brightness for bright galaxies may be genuinely fairly narrow, faint galaxies exist right across the (quite small) range of accessible surface brightnesses so no statement can be made about the true extent of the distribution. The lack of high surface brightness bright galaxies in the Virgo sample relative to an overall RC2 sample (mostly field galaxies) supports the contention that the star-formation rate is reduced in the inner region of the cluster for environmental reasons. (author)

  6. Trace fluorescent labeling for protein crystallization

    Energy Technology Data Exchange (ETDEWEB)

    Pusey, Marc, E-mail: marc.pusey@ixpressgenes.com; Barcena, Jorge; Morris, Michelle; Singhal, Anuj; Yuan, Qunying; Ng, Joseph [iXpressGenes Inc., 601 Genome Way, Huntsville, AL 35810 (United States)

    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.

  7. Coronal bright points associated with minifilament eruptions

    International Nuclear Information System (INIS)

    Coronal bright points (CBPs) are small-scale, long-lived coronal brightenings that always correspond to photospheric network magnetic features of opposite polarity. In this paper, we subjectively adopt 30 CBPs in a coronal hole to study their eruptive behavior using data from the Atmospheric Imaging Assembly (AIA) and the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory. About one-quarter to one-third of the CBPs in the coronal hole go through one or more minifilament eruption(s) (MFE(s)) throughout their lifetimes. The MFEs occur in temporal association with the brightness maxima of CBPs and possibly result from the convergence and cancellation of underlying magnetic dipoles. Two examples of CBPs with MFEs are analyzed in detail, where minifilaments appear as dark features of a cool channel that divide the CBPs along the neutral lines of the dipoles beneath. The MFEs show the typical rising movements of filaments and mass ejections with brightenings at CBPs, similar to large-scale filament eruptions. Via differential emission measure analysis, it is found that CBPs are heated dramatically by their MFEs and the ejected plasmas in the MFEs have average temperatures close to the pre-eruption BP plasmas and electron densities typically near 109 cm–3. These new observational results indicate that CBPs are more complex in dynamical evolution and magnetic structure than previously thought.

  8. At Bright Band Inside Victoria Crater

    Science.gov (United States)

    2007-01-01

    A layer of light-toned rock exposed inside Victoria Crater in the Meridiani Planum region of Mars appears to mark where the surface was at the time, many millions of years ago, when an impact excavated the crater. NASA's Mars Exploration Rover Opportunity drove to this bright band as the science team's first destination for the rover during investigations inside the crater. Opportunity's left front hazard-identification camera took this image just after the rover finished a drive of 2.25 meters (7 feet, 5 inches) during the rover's 1,305th Martian day, or sol, (Sept. 25, 2007). The rocks beneath the rover and its extended robotic arm are part of the bright band. Victoria Crater has a scalloped shape of alternating alcoves and promontories around the crater's circumference. Opportunity descended into the crater two weeks earlier, within an alcove called 'Duck Bay.' Counterclockwise around the rim, just to the right of the arm in this image, is a promontory called 'Cabo Frio.'

  9. A novel fluorescent assay for sucrose transporters

    Directory of Open Access Journals (Sweden)

    Gora Peter J

    2012-04-01

    Full Text Available Abstract Background We have developed a novel assay based on the ability of type I sucrose uptake transporters (SUTs to transport the fluorescent coumarin β-glucoside, esculin. Budding yeast (Saccharomyces cerevisiae is routinely used for the heterologous expression of SUTs and does not take up esculin. Results When type I sucrose transporters StSUT1 from potato or AtSUC2 from Arabidopsis were expressed in yeast, the cells were able to take up esculin and became brightly fluorescent. We tested a variety of incubation times, esculin concentrations, and buffer pH values and found that for these transporters, a 1 hr incubation at 0.1 to 1 mM esculin at pH 4.0 produced fluorescent cells that were easily distinguished from vector controls. Esculin uptake was assayed by several methods including fluorescence microscopy, spectrofluorometry and fluorescence-activiated cell sorting (FACS. Expression of the type II sucrose transporter OsSUT1 from rice did not result in increased esculin uptake under any conditions tested. Results were reproduced successfully in two distinct yeast strains, SEY6210 (an invertase mutant and BY4742. Conclusions The esculin uptake assay is rapid and sensitive and should be generally useful for preliminary tests of sucrose transporter function by heterologous expression in yeast. This assay is also suitable for selection of yeast showing esculin uptake activity using FACS.

  10. FAA Fluorescent Penetrant Laboratory Inspections

    Energy Technology Data Exchange (ETDEWEB)

    WINDES,CONNOR L.; MOORE,DAVID G.

    2000-08-02

    The Federal Aviation Administration Airworthiness Assurance NDI Validation Center currently assesses the capability of various non-destructive inspection (NDI) methods used for analyzing aircraft components. The focus of one such exercise is to evaluate the sensitivity of fluorescent liquid penetrant inspection. A baseline procedure using the water-washable fluorescent penetrant method defines a foundation for comparing the brightness of low cycle fatigue cracks in titanium test panels. The analysis of deviations in the baseline procedure will determine an acceptable range of operation for the steps in the inspection process. The data also gives insight into the depth of each crack and which step(s) of the inspection process most affect penetrant sensitivities. A set of six low cycle fatigue cracks produced in 6.35-mm thick Ti-6Al-4V specimens was used to conduct the experiments to produce sensitivity data. The results will document the consistency of the crack readings and compare previous experiments to find the best parameters for water-washable penetrant.

  11. New Distant Comet Headed for Bright Encounter

    Science.gov (United States)

    1995-08-01

    How Impressive Will Comet Hale-Bopp Become in 1997 ? A very unusual comet was discovered last month, on its way from the outer reaches of the solar system towards the Sun. Although it is still situated beyond the orbit of Jupiter, it is so bright that it can be observed in even small telescopes. It has been named `Hale-Bopp' after the discoverers and is already of great interest to cometary astronomers. No less than seven telescopes have been used at the ESO La Silla observatory for the first observations of the new object. Together with data gathered at other sites, their aim is to elucidate the nature of this comet and also to determine whether there is reason to hope that it will become a bright and beautiful object in the sky from late 1996 and well into 1997. Further observations are now being planned at ESO and elsewhere to monitor closely the behaviour of this celestial visitor during the coming months. Discovery circumstances The comet was discovered on 23 July 1995, nearly simultaneously by two American amateur astronomers, Alan Hale of Cloudcroft (New Mexico) and Thomas Bopp of Glendale (Arizona). Although the chronology is slightly uncertain, it appears that Hale first saw it some 10 - 20 minutes before Bopp, at 06:10 - 06:15 UT on that day. In any case, he informed the IAU Central Bureau for Astronomical Telegrams (CBAT) in Cambridge (Massachussetts) about his discovery by email already at 06:50 UT, while Bopp's message was filed more than 2 hours later, after he had driven back to his home, 140 km from where he had been observing. Upon receipt of these messages, Brian Marsden at the CBAT assigned the designation `1995 O1' (indicating that it is the first comet found in the second half of July 1995). After further sightings had been made by other observers, and according to the venerable astronomical tradition, the new object was named after the discoverers. The magnitude, reported as 10.5 by Hale, is not unusual for a comet that is discovered within

  12. Interfacing click chemistry with automated oligonucleotide synthesis for the preparation of fluorescent DNA probes containing internal xanthene and cyanine dyes

    DEFF Research Database (Denmark)

    Astakhova, I Kira; Wengel, Jesper

    2013-01-01

    : Considerable Stokes shifts (40-110 nm), quenched fluorescence of single-stranded probes accompanied by up to 7.7-fold light-up effect of emission upon target DNA/RNA binding, remarkable sensitivity to single-nucleotide mismatches, generally high fluorescence brightness values (FB up to 26), and hence low limit...

  13. Fundamentals of fluorescence and fluorescence microscopy.

    Science.gov (United States)

    Wolf, David E

    2013-01-01

    This chapter discusses the fundamental physics of fluorescence. The application of fluorescence to microscopy represents an important transition in the development of microscopy, particularly as it applies to biology. It enables quantitating the amounts of specific molecules within a cell, determining whether molecules are complexing on a molecular level, measuring changes in ionic concentrations within cells and organelles, and measuring molecular dynamics. This chapter also discusses the issues important to quantitative measurement of fluorescence and focuses on four of quantitative measurements of fluorescence--boxcar-gated detection, streak cameras, photon correlation, and phase modulation. Although quantitative measurement presents many pitfalls to the beginner, it also presents significant opportunities to one skilled in the art. This chapter also examines how fluorescence is measured in the steady state and time domain and how fluorescence is applied in the modern epifluorescence microscope. PMID:23931503

  14. Onsite naked eye determination of cysteine and homocysteine using quencher displacement-induced fluorescence recovery of the dual-emission hybrid probes with desired intensity ratio.

    Science.gov (United States)

    Wang, Kan; Qian, Jing; Jiang, Ding; Yang, Zhengting; Du, Xiaojiao; Wang, Kun

    2015-03-15

    Simple, inexpensive, portable sensing strategies for those clinically relevant molecules have attained a significant positive impact on the health care system. Herein, we have prepared a dual-emission ratiometric fluorescence probe with desired intensity ratio and demonstrated its efficiency for onsite naked eye determination of cysteine (Cys) and homocysteine (Hcy). The hybrid probe has been designed by hybridizing two differently sized CdTe quantum dots (QDs), in which the red-emitting CdTe QDs (rQDs) entrapped in the silica sphere acting as the reference signal, and the green-emitting CdTe QDs (gQDs) covalently attached on the silica surface serving as the response signal. When 1,10-phenanthroline with strong coordination ability to Cd atoms in gQDs was introduced, the fluorescence of the gQDs was effectively quenched, while the fluorescence of the rQDs stayed constant. Upon exposure to different contents of Cys or Hcy, the fluorescence of gQDs can be recovered gradually due to the displacement of the quencher. Based on the background signal of rQDs, the variations of the sensing system display continuous fluorescence color changes from red to green, which can be easily observed by the naked eye. The assay requires ∼20min and has a detection limit of 2.5 and 1.7μM for Cys and Hcy, respectively. Furthermore, we demonstrate that this sensing scheme can be fully integrated in a filter paper-based assay, thus enabling a potential point-of-care application featuring easy operation, low power consumption, and low fabrication costs. PMID:25461142

  15. Brightness temperature for 166 radio sources

    Institute of Scientific and Technical Information of China (English)

    Jun-Hui Fan; Yong Huang; Yu-Hai Yuan; Jiang-He Yang; Yi Liu; Jun Tao; Ying Gao; Tong-Xu Hua; Rui-Guang Lin; Jiang-Shui Zhang; Jing-Yi Zhang; Yi-Ping Qin

    2009-01-01

    Using the database of the University of Michigan Radio Astronomy Observatory (UMRAO) at three radio frequencies (4.8, 8 and 14.5 GHz), we determined the short-term variability timescales for 166 radio sources. The timescales are 0.15d (2007+777) to 176.17d (0528-250) with an average timescale of △tobs=17.1±16.5d for the whole sample. The timescales are used to calculate the brightness temperatures, TB. The value of log TB is in the range of log TB = 10.47 to 19.06 K. In addition, we also estimated the boosting factor for the sources. The correlation between the polarization and the Doppler factor is also discussed.

  16. Modelling Solar and Stellar Brightness Variabilities

    Science.gov (United States)

    Yeo, K. L.; Shapiro, A. I.; Krivova, N. A.; Solanki, S. K.

    2016-04-01

    Total and spectral solar irradiance, TSI and SSI, have been measured from space since 1978. This is accompanied by the development of models aimed at replicating the observed variability by relating it to solar surface magnetism. Despite significant progress, there remains persisting controversy over the secular change and the wavelength-dependence of the variation with impact on our understanding of the Sun's influence on the Earth's climate. We highlight the recent progress in TSI and SSI modelling with SATIRE. Brightness variations have also been observed for Sun-like stars. Their analysis can profit from knowledge of the solar case and provide additional constraints for solar modelling. We discuss the recent effort to extend SATIRE to Sun-like stars.

  17. High brightness angled cavity quantum cascade lasers

    International Nuclear Information System (INIS)

    A quantum cascade laser (QCL) with an output power of 203 W is demonstrated in pulsed mode at 283 K with an angled cavity. The device has a ridge width of 300 μm, a cavity length of 5.8 mm, and a tilt angle of 12°. The back facet is high reflection coated, and the front facet is anti-reflection coated. The emitting wavelength is around 4.8 μm. In distinct contrast to a straight cavity broad area QCL, the lateral far field is single lobed with a divergence angle of only 3°. An ultrahigh brightness value of 156 MW cm−2 sr−1 is obtained, which marks the brightest QCL to date

  18. Considerations for high-brightness electron sources

    International Nuclear Information System (INIS)

    Particle accelerators are now used in many areas of physics research and in industrial and medical applications. New uses are being studied to address major societal needs in energy production, materials research, generation of intense beams of radiation at optical and suboptical wavelengths, treatment of various kinds of waste, and so on. Many of these modern applications require a high intensity beam at the desired energy, along with a very good beam quality in terms of the beam confinement, aiming, or focusing. Considerations for ion and electron accelerators are often different, but there are also many commonalties, and in fact, techniques derived for one should perhaps more often be considered for the other as well. We discuss some aspects of high-brightness electron sources here from that point of view. 6 refs

  19. High brightness angled cavity quantum cascade lasers

    Energy Technology Data Exchange (ETDEWEB)

    Heydari, D.; Bai, Y.; Bandyopadhyay, N.; Slivken, S.; Razeghi, M., E-mail: razeghi@eecs.northwestern.edu [Center for Quantum Devices, Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, Illinois 60208 (United States)

    2015-03-02

    A quantum cascade laser (QCL) with an output power of 203 W is demonstrated in pulsed mode at 283 K with an angled cavity. The device has a ridge width of 300 μm, a cavity length of 5.8 mm, and a tilt angle of 12°. The back facet is high reflection coated, and the front facet is anti-reflection coated. The emitting wavelength is around 4.8 μm. In distinct contrast to a straight cavity broad area QCL, the lateral far field is single lobed with a divergence angle of only 3°. An ultrahigh brightness value of 156 MW cm{sup −2 }sr{sup −1} is obtained, which marks the brightest QCL to date.

  20. Dark Skies, Bright Kids Year 7

    Science.gov (United States)

    Bittle, Lauren E.; Johnson, Kelsey E.; Borish, H. Jacob; Burkhardt, Andrew; Firebaugh, Ariel; Hancock, Danielle; Rochford Hayes, Christian; Linden, Sean; Liss, Sandra; Matthews, Allison; Prager, Brian; Pryal, Matthew; Sokal, Kimberly R.; Troup, Nicholas William; Wenger, Trey

    2016-01-01

    We present updates from our seventh year of operation including new club content, continued assessments, and our fifth annual Star Party. Dark Skies, Bright Kids (DSBK) is an entirely volunteer-run outreach organization based out of the Department of Astronomy at the University of Virginia. Our core mission is to enhance elementary science education and literacy in Central Virginia through fun, hands-on activities that introduce basic Astronomy concepts. Our primary focus is hosting an 8-10 week after-school astronomy club at underserved elementary and middle schools. Each week, DSBK volunteers take the role of coaches to introduce astronomy-related concepts ranging from the Solar System to galaxies to astrobiology, and to lead students in interactive learning activities. Another hallmark of DSBK is hosting our Annual Central Virginia Star Party, a free event open to the community featuring star-gazing and planetarium shows.

  1. Brightness-equalized quantum dots: Engineering strategies derived from spectral trends

    Science.gov (United States)

    Smith, Andrew M.; Lim, Sung Jun

    2015-03-01

    Quantum dots are semiconductor nanocrystals that absorb and emit light at wavelengths tunable by the size of the crystal. Size-tuning provides access to a broad range of optical spectra, however it is fundamentally problematic for many applications because it leads to a large mismatch in absorption cross-section and fluorescence brightness across a series of colors. We have recently demonstrated engineering strategies to generate multicolor, extinction-matched, and brightness-matched quantum dots based on colloidal multi-domain core/shell structures. We use alloyed cores with composition-tunable bandgaps and finely adjust the domain size and electronic properties of the shell to precisely match both absorption cross-section and quantum yield. Using this strategy, it is possible to tune fluorescence wavelength, extinction, and quantum yield independently, vastly expanding the photophysical landscape of these materials. Moreover compared with conventional size-tuning strategies, this enables access to a wider spectral range with compact dimensions. The equalized optical properties translate from the ensemble level down to the single-molecule level, setting the stage for new possibilities in highly quantitative, multiplexed imaging in cells and tissue. However selection of appropriate structural parameters to generate specific optical properties is challenging without insight into the photophysics of these materials. Here we describe the evolution of the optical properties of alloyed cores during the shell growth process that provide new insights into general engineering strategies.

  2. Moon night sky brightness simulation for the Xinglong station

    International Nuclear Information System (INIS)

    Using a sky brightness monitor at the Xinglong station of National Astronomical Observatories, Chinese Academy of Sciences, we collected data from 22 dark clear nights and 90 moon nights. We first measured the sky brightness variation with time for dark nights and found a clear correlation between sky brightness and human activity. Then with a modified sky brightness model of moon nights and data from these nights, we derived the typical value for several important parameters in the model. With these results, we calculated the sky brightness distribution under a given moon condition for the Xinglong station. Furthermore, we simulated the sky brightness distribution of a moon night for a telescope with a 5° field of view (such as LAMOST). These simulations will be helpful for determining the limiting magnitude and exposure time, as well as planning the survey for LAMOST during moon nights

  3. Variability, Brightness Temperature, Superluminal Motion, Doppler Boosting, and Related Issues

    CERN Document Server

    Kellermann, K I

    2003-01-01

    We review the observations of rapid flux density variations in compact radio sources, and discuss the inverse Compton limit to the maximum brightness temperature of incoherent synchrotron sources in comparison with recent VLBA observations. The apparent agreement of the theoretical brightness temperature limit due to inverse Compton cooling and the brightness temperatures observed by early VLBI observations appears to have been fortuitous. VLBA observations have greatly improved the quality of the data, but many of the early issues remain unresolved.

  4. Annular bright and dark field imaging of soft materials

    International Nuclear Information System (INIS)

    Here polyethylene, as an example of an important soft material, was studied by STEM annular bright and dark field. The contrast as function of the probe size/shape and the detector collection angle are discussed. The results are compared to conventional bright field transmission electron microscopy, electron energy filtered imaging and energy dispersive spectroscopy mapping. Annular bright and dark field gave a higher contrast than conventional transmission and analytical mapping techniques

  5. Research on Brightness Measurement of Intense Electron Beam

    CERN Document Server

    Wang, Yuan; Zhang, Huang; Yang, GuoJun; Li, YiDing; Li, Jin

    2015-01-01

    The mostly research fasten on high emission density of injector to study electron beam's brightness in LIA. Using the injector(2MeV) was built to research brightness of multi-pulsed high current(KA) electron beam, and researchs three measurement method (the pepper-pot method, beam collimator without magnetic field, beam collimator with magnetic field method) to detect beam's brightness with time-resolved measurement system.

  6. INVESTIGATION ON THE CAUSES OF EUCALYPTUS KRAFT PULP BRIGHTNESS REVERSION

    OpenAIRE

    Kátia M. M. Eiras; Jorge Luiz Colodette; Ana Márcia M. L. Carvalho

    2005-01-01

    Some high brightness eucalyptus Kraft pulps have shown poor brightness stability. In most cases, the causes have notbeen identified and permanent solutions have not been found. This work focused on evaluating the brightness stability profile of pulpsbleached by in sequences such as O(DC)(PO)DD, O(DC)(PO)DP, OD(PO)DD, OD(PO)DP, ODHT(PO)DD, ODHT(PO)DP, OA/D(PO)DD, OA/D(PO)DP, OAD(PO)DD and O(Ze)D(PO). Brightness stability tests induced by according to Tappi UM200 procedureon samples bleached to...

  7. Study of Three-Dimensional Image Brightness Loss in Stereoscopy

    Directory of Open Access Journals (Sweden)

    Hsing-Cheng Yu

    2015-10-01

    Full Text Available When viewing three-dimensional (3D images, whether in cinemas or on stereoscopic televisions, viewers experience the same problem of image brightness loss. This study aims to investigate image brightness loss in 3D displays, with the primary aim being to quantify the image brightness degradation in the 3D mode. A further aim is to determine the image brightness relationship to the corresponding two-dimensional (2D images in order to adjust the 3D-image brightness values. In addition, the photographic principle is used in this study to measure metering values by capturing 2D and 3D images on television screens. By analyzing these images with statistical product and service solutions (SPSS software, the image brightness values can be estimated using the statistical regression model, which can also indicate the impact of various environmental factors or hardware on the image brightness. In analysis of the experimental results, comparison of the image brightness between 2D and 3D images indicates 60.8% degradation in the 3D image brightness amplitude. The experimental values, from 52.4% to 69.2%, are within the 95% confidence interval

  8. Principles of fluorescence techniques

    CERN Document Server

    2016-01-01

    Fluorescence techniques are being used and applied increasingly in academics and industry. The Principles of Fluorescence Techniques course will outline the basic concepts of fluorescence techniques and the successful utilization of the currently available commercial instrumentation. The course is designed for students who utilize fluorescence techniques and instrumentation and for researchers and industrial scientists who wish to deepen their knowledge of fluorescence applications. Key scientists in the field will deliver theoretical lectures. The lectures will be complemented by the direct utilization of steady-state and lifetime fluorescence instrumentation and confocal microscopy for FLIM and FRET applications provided by leading companies.

  9. Reviews in fluorescence 2010

    CERN Document Server

    Geddes, Chris D

    2011-01-01

    ""Reviews in Fluorescence 2010"", the seventh volume of the book serial from Springer, serves as a comprehensive collection of current trends and emerging hot topics in the field of fluorescence and closely related disciplines. It summarizes the year's progress in fluorescence and its applications, with authoritative analytical reviews specialized enough to be attractive to professional researchers, yet also appealing to the wider audience of scientists in related disciplines of fluorescence. ""Reviews in Fluorescence"" offers an essential reference material for any lab working in the fluoresc

  10. Fluorescence of thermal control coatings on S0069 and A0114

    International Nuclear Information System (INIS)

    Many of the thermal control surfaces exposed to the space environment during the 5.8 year LDEF mission experienced changes in fluorescence. All of the thermal control coatings flown on LDEF experiments S0069 and A0114 were characterized for fluorescence under ambient conditions. Some of the black coatings, having protective overcoats, appear bright yellow under ultraviolet exposure. Urethane based coatings exhibited emission spectra shifts toward longer wavelengths in the visible range. Zinc oxide pigment based coatings experienced a quenching of fluorescence, while zinc orthotitanate pigment based and other ceramic type coatings had no measurable fluorescence

  11. The relation between isolated tree brightness temperature and grass background brightness temperature

    Science.gov (United States)

    Krusinger, A. E.

    1983-08-01

    This study involves thermal infrared measurement for the determination of the diurnal and seasonal aspects of the relations between isolated evergreen tress and a cut grass background and between a large truck brightness temperature and cut grass, uncut grass, and bare soil backgrounds. Seasonal changes in the tree brightness temperature-background brightness temperature contrast ranged from 4 to 5 C in February and March to 1 to 2 C in July. At night, the thermal contrast between trees and background was found to vary inversely with long wave incoming radiation, which is a measure of cloudiness. A study of the change in the thermal contrast during the night showed that, during clear weather, the contrast was at a peak a few hours after sundown and decreased the rest of the night. In overcast conditions, a reduced contrast peak occurred at sundown and very gradually diminished through the night. Isothermal conditions were found to occur in the early mornings, and the time of these occurrences changed seasonally, in a systematic manner.

  12. Larger Planet Radii Inferred from Stellar "Flicker" Brightness Variations of Bright Planet Host Stars

    CERN Document Server

    Bastien, Fabienne A; Pepper, Joshua

    2014-01-01

    Most extrasolar planets have been detected by their influence on their parent star, typically either gravitationally (the Doppler method) or by the small dip in brightness as the planet blocks a portion of the star (the transit method). Therefore, the accuracy with which we know the masses and radii of extrasolar planets depends directly on how well we know those of the stars, the latter usually determined from the measured stellar surface gravity, logg. Recent work has demonstrated that the short-timescale brightness variations ("flicker") of stars can be used to measure logg to a high accuracy of ~0.1-0.2 dex (Bastien et al. 2013). Here, we use flicker measurements of 289 bright (Kepmag<13) candidate planet-hosting stars with Teff=4500-6650 K to re-assess the stellar parameters and determine the resulting impact on derived planet properties. This re-assessment reveals that for the brightest planet-host stars, an astrophysical bias exists that contaminates the stellar sample with evolved stars: nearly 50%...

  13. High Brightness Neutron Source for Radiography

    Energy Technology Data Exchange (ETDEWEB)

    Cremer, J. T.; Piestrup, Melvin, A.; Gary, Charles, K.; Harris, Jack, L. Williams, David, J.; Jones, Glenn, E.; Vainionpaa, J. , H.; Fuller, Michael, J.; Rothbart, George, H.; Kwan, J., W.; Ludewigt, B., A.; Gough, R.., A..; Reijonen, Jani; Leung, Ka-Ngo

    2008-12-08

    This research and development program was designed to improve nondestructive evaluation of large mechanical objects by providing both fast and thermal neutron sources for radiography. Neutron radiography permits inspection inside objects that x-rays cannot penetrate and permits imaging of corrosion and cracks in low-density materials. Discovering of fatigue cracks and corrosion in piping without the necessity of insulation removal is possible. Neutron radiography sources can provide for the nondestructive testing interests of commercial and military aircraft, public utilities and petrochemical organizations. Three neutron prototype neutron generators were designed and fabricated based on original research done at the Lawrence Berkeley National Laboratory (LBNL). The research and development of these generators was successfully continued by LBNL and Adelphi Technology Inc. under this STTR. The original design goals of high neutron yield and generator robustness have been achieved, using new technology developed under this grant. In one prototype generator, the fast neutron yield and brightness was roughly 10 times larger than previously marketed neutron generators using the same deuterium-deuterium reaction. In another generator, we integrate a moderator with a fast neutron source, resulting in a high brightness thermal neutron generator. The moderator acts as both conventional moderator and mechanical and electrical support structure for the generator and effectively mimics a nuclear reactor. In addition to the new prototype generators, an entirely new plasma ion source for neutron production was developed. First developed by LBNL, this source uses a spiral antenna to more efficiently couple the RF radiation into the plasma, reducing the required gas pressure so that the generator head can be completely sealed, permitting the possible use of tritium gas. This also permits the generator to use the deuterium-tritium reaction to produce 14-MeV neutrons with increases

  14. Rainbow Vectors for Broad-Range Bacterial Fluorescence Labeling.

    Science.gov (United States)

    Barbier, Mariette; Damron, F Heath

    2016-01-01

    Since their discovery, fluorescent proteins have been widely used to study protein function, localization or interaction, promoter activity and regulation, drug discovery or for non-invasive imaging. They have been extensively modified to improve brightness, stability, and oligomerization state. However, only a few studies have focused on understanding the dynamics of fluorescent proteins expression in bacteria. In this work, we developed a set plasmids encoding 12 fluorescent proteins for bacterial labeling to facilitate the study of pathogen-host interactions. These broad-spectrum plasmids can be used with a wide variety of Gram-negative microorganisms including Escherichia coli, Pseudomonas aeruginosa, Burkholderia cepacia, Bordetella bronchiseptica, Shigella flexneri or Klebsiella pneumoniae. For comparison, fluorescent protein expression and physical characteristics in Escherichia coli were analyzed using fluorescence microscopy, flow cytometry and in vivo imaging. Fluorescent proteins derived from the Aequorea Victoria family showed high photobleaching, while proteins form the Discosoma sp. and the Fungia coccina family were more photostable for microscopy applications. Only E2-Crimson, mCherry and mKeima were successfully detected for in vivo applications. Overall, E2-Crimson was the fastest maturing protein tested in E. coli with the best overall performance in the study parameters. This study provides a unified comparison and comprehensive characterization of fluorescent protein photostability, maturation and toxicity, and offers general recommendations on the optimal fluorescent proteins for in vitro and in vivo applications. PMID:26937640

  15. Rainbow Vectors for Broad-Range Bacterial Fluorescence Labeling.

    Directory of Open Access Journals (Sweden)

    Mariette Barbier

    Full Text Available Since their discovery, fluorescent proteins have been widely used to study protein function, localization or interaction, promoter activity and regulation, drug discovery or for non-invasive imaging. They have been extensively modified to improve brightness, stability, and oligomerization state. However, only a few studies have focused on understanding the dynamics of fluorescent proteins expression in bacteria. In this work, we developed a set plasmids encoding 12 fluorescent proteins for bacterial labeling to facilitate the study of pathogen-host interactions. These broad-spectrum plasmids can be used with a wide variety of Gram-negative microorganisms including Escherichia coli, Pseudomonas aeruginosa, Burkholderia cepacia, Bordetella bronchiseptica, Shigella flexneri or Klebsiella pneumoniae. For comparison, fluorescent protein expression and physical characteristics in Escherichia coli were analyzed using fluorescence microscopy, flow cytometry and in vivo imaging. Fluorescent proteins derived from the Aequorea Victoria family showed high photobleaching, while proteins form the Discosoma sp. and the Fungia coccina family were more photostable for microscopy applications. Only E2-Crimson, mCherry and mKeima were successfully detected for in vivo applications. Overall, E2-Crimson was the fastest maturing protein tested in E. coli with the best overall performance in the study parameters. This study provides a unified comparison and comprehensive characterization of fluorescent protein photostability, maturation and toxicity, and offers general recommendations on the optimal fluorescent proteins for in vitro and in vivo applications.

  16. Ultra-bright alkylated graphene quantum dots

    Science.gov (United States)

    Feng, Lan; Tang, Xing-Yan; Zhong, Yun-Xin; Liu, Yue-Wen; Song, Xue-Huan; Deng, Shun-Liu; Xie, Su-Yuan; Yan, Jia-Wei; Zheng, Lan-Sun

    2014-10-01

    Highly efficient and stable photoluminescence (PL) are urgently desired for graphene quantum dots (GQDs) to facilitate their prospective applications as optical materials. Here, we report the facile and straightforward synthesis of alkylated graphene quantum dots (AGQDs) via the solvothermal reaction of propagatively alkylated graphene sheets (PAGenes). In contrast to most GQDs reported so far, the synthesized AGQDs process pH-independent and ultra-bright PL with a relative quantum yield of up to 65%. Structural and chemical composition characterization demonstrated that the synthesized AGQDs are nearly oxygen-defect-free with alkyl groups decorated on edges and basal plane, which may contribute to their greatly improved pH tolerance and high quantum efficiency. The photocatalytic performance of AGQDs-P25 nanocomposites was evaluated by the degradation of Rhodamine B under visible light. The photocatalytic rate is ca. 5.9 times higher than that of pure P25, indicating that AGQDs could harness the visible spectrum of sunlight for energy conversion or environmental therapy.Highly efficient and stable photoluminescence (PL) are urgently desired for graphene quantum dots (GQDs) to facilitate their prospective applications as optical materials. Here, we report the facile and straightforward synthesis of alkylated graphene quantum dots (AGQDs) via the solvothermal reaction of propagatively alkylated graphene sheets (PAGenes). In contrast to most GQDs reported so far, the synthesized AGQDs process pH-independent and ultra-bright PL with a relative quantum yield of up to 65%. Structural and chemical composition characterization demonstrated that the synthesized AGQDs are nearly oxygen-defect-free with alkyl groups decorated on edges and basal plane, which may contribute to their greatly improved pH tolerance and high quantum efficiency. The photocatalytic performance of AGQDs-P25 nanocomposites was evaluated by the degradation of Rhodamine B under visible light. The

  17. A Bright Future for Precision Medicine: Advances in Fluorescent Chemical Probe Design and Their Clinical Application.

    Science.gov (United States)

    Garland, Megan; Yim, Joshua J; Bogyo, Matthew

    2016-01-21

    The Precision Medicine Initiative aims to use advances in basic and clinical research to develop therapeutics that selectively target and kill cancer cells. Under the same doctrine of precision medicine, there is an equally important need to visualize these diseased cells to enable diagnosis, facilitate surgical resection, and monitor therapeutic response. Therefore, there is a great opportunity for chemists to develop chemically tractable probes that can image cancer in vivo. This review focuses on recent advances in the development of optical probes, as well as their current and future applications in the clinical management of cancer. The progress in probe development described here suggests that optical imaging is an important and rapidly developing field of study that encourages continued collaboration among chemists, biologists, and clinicians to further refine these tools for interventional surgical imaging, as well as for diagnostic and therapeutic applications. PMID:26933740

  18. A route to brightly fluorescent carbon nanotubes for near-infrared imaging in mice

    OpenAIRE

    Welsher, Kevin; Liu, Zhuang; Sarah P Sherlock; Robinson, Joshua Tucker; Chen, Zhuo; Daranciang, Dan; Dai, Hongjie

    2009-01-01

    The near-infrared photoluminescence intrinsic to semiconducting single-walled carbon nanotubes is ideal for biological imaging owing to the low autofluorescence and deep tissue penetration in the near-infrared region beyond 1 µm. However, biocompatible single-walled carbon nanotubes with high quantum yield have been elusive. Here, we show that sonicating single-walled carbon nanotubes with sodium cholate, followed by surfactant exchange to form phospholipid–polyethylene glycol coated nanotube...

  19. Fast automated yeast cell counting algorithm using bright-field and fluorescence microscopic images

    OpenAIRE

    Hong, Dongpyo; Lee, Gwanghee; Jung, Neon Cheol; Jeon, Moongu

    2013-01-01

    Background The faithful determination of the concentration and viability of yeast cells is important for biological research as well as industry. To this end, it is important to develop an automated cell counting algorithm that can provide not only fast but also accurate and precise measurement of yeast cells. Results With the proposed method, we measured the precision of yeast cell measurements by using 0%, 25%, 50%, 75% and 100% viability samples. As a result, the actual viability measured ...

  20. Automated local bright feature image analysis of nuclear protein distribution identifies changes in tissue phenotype

    International Nuclear Information System (INIS)

    The organization of nuclear proteins is linked to cell and tissue phenotypes. When cells arrest proliferation, undergo apoptosis, or differentiate, the distribution of nuclear proteins changes. Conversely, forced alteration of the distribution of nuclear proteins modifies cell phenotype. Immunostaining and fluorescence microscopy have been critical for such findings. However, there is an increasing need for quantitative analysis of nuclear protein distribution to decipher epigenetic relationships between nuclear structure and cell phenotype, and to unravel the mechanisms linking nuclear structure and function. We have developed imaging methods to quantify the distribution of fluorescently-stained nuclear protein NuMA in different mammary phenotypes obtained using three-dimensional cell culture. Automated image segmentation of DAPI-stained nuclei was generated to isolate thousands of nuclei from three-dimensional confocal images. Prominent features of fluorescently-stained NuMA were detected using a novel local bright feature analysis technique, and their normalized spatial density calculated as a function of the distance from the nuclear perimeter to its center. The results revealed marked changes in the distribution of the density of NuMA bright features as non-neoplastic cells underwent phenotypically normal acinar morphogenesis. In contrast, we did not detect any reorganization of NuMA during the formation of tumor nodules by malignant cells. Importantly, the analysis also discriminated proliferating non-neoplastic cells from proliferating malignant cells, suggesting that these imaging methods are capable of identifying alterations linked not only to the proliferation status but also to the malignant character of cells. We believe that this quantitative analysis will have additional applications for classifying normal and pathological tissues

  1. Automated local bright feature image analysis of nuclear proteindistribution identifies changes in tissue phenotype

    Energy Technology Data Exchange (ETDEWEB)

    Knowles, David; Sudar, Damir; Bator, Carol; Bissell, Mina

    2006-02-01

    The organization of nuclear proteins is linked to cell and tissue phenotypes. When cells arrest proliferation, undergo apoptosis, or differentiate, the distribution of nuclear proteins changes. Conversely, forced alteration of the distribution of nuclear proteins modifies cell phenotype. Immunostaining and fluorescence microscopy have been critical for such findings. However, there is an increasing need for quantitative analysis of nuclear protein distribution to decipher epigenetic relationships between nuclear structure and cell phenotype, and to unravel the mechanisms linking nuclear structure and function. We have developed imaging methods to quantify the distribution of fluorescently-stained nuclear protein NuMA in different mammary phenotypes obtained using three-dimensional cell culture. Automated image segmentation of DAPI-stained nuclei was generated to isolate thousands of nuclei from three-dimensional confocal images. Prominent features of fluorescently-stained NuMA were detected using a novel local bright feature analysis technique, and their normalized spatial density calculated as a function of the distance from the nuclear perimeter to its center. The results revealed marked changes in the distribution of the density of NuMA bright features as non-neoplastic cells underwent phenotypically normal acinar morphogenesis. In contrast, we did not detect any reorganization of NuMA during the formation of tumor nodules by malignant cells. Importantly, the analysis also discriminated proliferating non-neoplastic cells from proliferating malignant cells, suggesting that these imaging methods are capable of identifying alterations linked not only to the proliferation status but also to the malignant character of cells. We believe that this quantitative analysis will have additional applications for classifying normal and pathological tissues.

  2. Fluorescent optical position sensor

    Science.gov (United States)

    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.

  3. Fluorescence correlation spectroscopy

    NARCIS (Netherlands)

    M.A. Hink

    2015-01-01

    Fluorescence fluctuation spectroscopy techniques allow the quantification of fluorescent molecules present at the nanomolar concentration level. After a brief introduction to the technique, this chapter presents a protocol including background information in order to measure and quantify the molecul

  4. Fluorenyl benzothiadiazole and benzoselenadiazole near-IR fluorescent probes for two-photon fluorescence imaging (Conference Presentation)

    Science.gov (United States)

    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 (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.

  5. Dark and bright vortex solitons in electromagnetically induced transparent media

    International Nuclear Information System (INIS)

    We show that dark and bright vortex solitons can exist in three-state electromagnetically induced transparent media under some appropriate conditions. We also analyse the stability of the dark and bright vortex solitons. This work may provide other research opportunities in nonlinear optical experiments and may result in a substantial impact on technology

  6. Analysis of Bright Harvest Remote Analysis for Residential Solar Installations

    Energy Technology Data Exchange (ETDEWEB)

    Nangle, John [National Renewable Energy Lab. (NREL), Golden, CO (United States); Simon, Joseph [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-06-17

    Bright Harvest provides remote shading analysis and design products for residential PV system installers. The National Renewable Energy Laboratory (NREL) through the NREL Commercialization Assistance Program, completed comparative assessments between on-site measurements and remotely calculated values to validate the accuracy of Bright Harvest’s remote shading and power generation.

  7. Modular Zero Energy. BrightBuilt Home

    Energy Technology Data Exchange (ETDEWEB)

    Aldrich, Robb [Consortium for Advanced Residential Buildings (CARB), Norwalk, CT (United States). Steven Winters Associates, Inc.; Butterfield, Karla [Consortium for Advanced Residential Buildings (CARB), Norwalk, CT (United States). Steven Winters Associates, Inc.

    2016-03-01

    Kaplan Thompson Architects (KTA) has specialized in sustainable, energy-efficient buildings, and they have designed several custom, zero-energy homes in New England. These zero-energy projects have generally been high-end, custom homes with budgets that could accommodate advanced energy systems. In an attempt to make zero energy homes more affordable and accessible to a larger demographic, KTA explored modular construction as way to provide high-quality homes at lower costs. In the mid-2013, KTA formalized this concept when they launched BrightBuilt Home (BBH). The BBH mission is to offer a line of architect-designed, high-performance homes that are priced to offer substantial savings off the lifetime cost of a typical home and can be delivered in less time. For the past two years, CARB has worked with BBH and Keiser Homes (the primary modular manufacturer for BBH) to discuss challenges related to wall systems, HVAC, and quality control. In Spring of 2014, CARB and BBH began looking in detail on a home to be built in Lincolnville, ME by Black Bros. Builders. This report details the solution package specified for this modular plan and the challenges that arose during the project.

  8. Intercomparisons of Nine Sky Brightness Detectors

    Directory of Open Access Journals (Sweden)

    Henk Spoelstra

    2011-10-01

    Full Text Available Nine Sky Quality Meters (SQMs have been intercompared during a night time measurement campaign held in the Netherlands in April 2011. Since then the nine SQMs have been distributed across the Netherlands and form the Dutch network for monitoring night sky brightness. The goal of the intercomparison was to infer mutual calibration factors and obtain insight into the variability of the SQMs under different meteorological situations. An ensemble average is built from the individual measurements and used as a reference to infer the mutual calibration factors. Data required additional synchronization prior to the calibration determination, because the effect of moving clouds combined with small misalignments emerges as time jitter in the measurements. Initial scatter of the individual instruments lies between ±14%. Individual night time sums range from −16% to +20%. Intercalibration reduces this to 0.5%, and −7% to +9%, respectively. During the campaign the smallest luminance measured was 0.657 ± 0.003 mcd/m2 on 12 April, and the largest value was 5.94 ± 0.03 mcd/m2 on 2 April. During both occurrences interfering circumstances like snow cover or moonlight were absent.

  9. Bright visible light emission from graphene

    Science.gov (United States)

    Kim, Young Duck; Kim, Hakseong; Cho, Yujin; Ryoo, Ji Hoon; Park, Cheol-Hwan; Kim, Pilkwang; Kim, Yong Seung; Lee, Sunwoo; Li, Yilei; Park, Seung-Nam; Shim Yoo, Yong; Yoon, Duhee; Dorgan, Vincent E.; Pop, Eric; Heinz, Tony F.; Hone, James; Chun, Seung-Hyun; Cheong, Hyeonsik; Lee, Sang Wook; Bae, Myung-Ho; Park, Yun Daniel

    2015-08-01

    Graphene and related two-dimensional materials are promising candidates for atomically thin, flexible and transparent optoelectronics. In particular, the strong light-matter interaction in graphene has allowed for the development of state-of-the-art photodetectors, optical modulators and plasmonic devices. In addition, electrically biased graphene on SiO2 substrates can be used as a low-efficiency emitter in the mid-infrared range. However, emission in the visible range has remained elusive. Here, we report the observation of bright visible light emission from electrically biased suspended graphene devices. In these devices, heat transport is greatly reduced. Hot electrons (˜2,800 K) therefore become spatially localized at the centre of the graphene layer, resulting in a 1,000-fold enhancement in thermal radiation efficiency. Moreover, strong optical interference between the suspended graphene and substrate can be used to tune the emission spectrum. We also demonstrate the scalability of this technique by realizing arrays of chemical-vapour-deposited graphene light emitters. These results pave the way towards the realization of commercially viable large-scale, atomically thin, flexible and transparent light emitters and displays with low operation voltage and graphene-based on-chip ultrafast optical communications.

  10. Antilensing: the bright side of voids.

    Science.gov (United States)

    Bolejko, Krzysztof; Clarkson, Chris; Maartens, Roy; Bacon, David; Meures, Nikolai; Beynon, Emma

    2013-01-11

    More than half of the volume of our Universe is occupied by cosmic voids. The lensing magnification effect from those underdense regions is generally thought to give a small dimming contribution: objects on the far side of a void are supposed to be observed as slightly smaller than if the void were not there, which together with conservation of surface brightness implies net reduction in photons received. This is predicted by the usual weak lensing integral of the density contrast along the line of sight. We show that this standard effect is swamped at low redshifts by a relativistic Doppler term that is typically neglected. Contrary to the usual expectation, objects on the far side of a void are brighter than they would be otherwise. Thus the local dynamics of matter in and near the void is crucial and is only captured by the full relativistic lensing convergence. There are also significant nonlinear corrections to the relativistic linear theory, which we show actually underpredicts the effect. We use exact solutions to estimate that these can be more than 20% for deep voids. This remains an important source of systematic errors for weak lensing density reconstruction in galaxy surveys and for supernovae observations, and may be the cause of the reported extra scatter of field supernovae located on the edge of voids compared to those in clusters. PMID:23383886

  11. Lyman Alpha Mapping Project (LAMP) Brightness Maps

    Science.gov (United States)

    Retherford, Kurt D.; Gladstone, G.; Stern, S.; Egan, A. F.; Miles, P. F.; Parker, J. W.; Greathouse, T. K.; Davis, M. W.; Slater, D. C.; Kaufmann, D. E.; Versteeg, M. H.; Feldman, P. D.; Hurley, D. M.; Pryor, W. R.; Hendrix, A. R.

    2010-10-01

    The Lyman Alpha Mapping Project (LAMP) is an ultraviolet (UV) spectrograph on the Lunar Reconnaissance Orbiter (LRO) that is designed to map the lunar albedo at far-UV wavelengths. LAMP primarily measures interplanetary Hydrogen Lyman-alpha sky-glow and far-UV starlight reflected from the night-side lunar surface, including permanently shadowed regions (PSRs) near the poles. Dayside observations are also obtained. Brightness maps sorted by wavelength (including the Lyman-alpha wavelength of 121.6 nm) are reported for the polar regions, with a few regions of interest reported in more detail. LAMP's spectral range of 58 nm to 196 nm includes a water ice spectral feature near 160 nm, which provides a diagnostic tool for detecting water on the lunar surface that is complementary to recent discoveries using infrared and radio frequency techniques. Progress towards producing far-UV albedo maps and searching for water ice signatures will be reported. We'll discuss how LAMP data may address questions regarding how water is formed on the moon, transported through the lunar atmosphere, and deposited in the PSRs.

  12. Chromatic variations suppress suprathreshold brightness variations.

    Science.gov (United States)

    Kingdom, Frederick A A; Bell, Jason; Gheorghiu, Elena; Malkoc, Gokhan

    2010-01-01

    Most objects in natural scenes are suprathreshold in both color (chromatic) and luminance contrast. How salient is each dimension? We have developed a novel method employing a stimulus similar to that used by B. C. Regan and J. D. Mollon (1997) who studied the relative saliencies of the two chromatic cardinal directions. Our stimuli consist of left- and right-oblique modulations of color and/or luminance defined within a lattice of circles. In the "separated" condition, the two modulations were presented separately as forced-choice pairs, and the task was to indicate which was more salient. In the "combined" condition, the two orthogonal-in-orientation modulations were added, and the task was to indicate the more salient orientation. The ratio of color to luminance contrast at the PSE was calculated for both conditions. Across color directions, 48% more luminance contrast relative to color contrast was required to achieve a PSE in the "combined" compared to the "separated" condition. A second experiment showed that the PSE difference was due to the luminance being masked by the color, rather than due to superior color grouping. We conclude that suprathreshold brightness variations are masked by suprathreshold color variations. PMID:20884478

  13. Energy balance in a bright active prominence

    International Nuclear Information System (INIS)

    The transitions between ten levels and hydrogen atom continuum and 4S, 3D, 4P, Ca+ terms in a bright active prominence are considered. The role of electron impacts and solar radiation scattering taking account of optical thicknesses in all frequencies is considered. It has been found that hydrogen atoms and calcium ions radiate approximately equal amount of energy: 2.4x107 and 1.3x107 erg/cm2xs., respectively. The hydrogen atom radiation is by 2/3 due to solar radiation scattering, the contribution of the scattered radiation for various series and separate lines being unequal. The radiation in the n, k lines and in Ca+ infrared lines is almost completely ensured by electron impacts. Only the tenth part of the necessary energy is added on account of the solar radiation absorption. The total prominence radiation is half ensured due to solar radiation scattering. Approximately the same amount of energ is taken from the electron gas. The higher is q, the more significant becomes the role of electron impacts in hydrogen atom excitation and ionization. The q prominence duty factor value is near to unity

  14. Dark Skies, Bright Kids Year 6

    Science.gov (United States)

    Liss, Sandra; Troup, Nicholas William; Johnson, Kelsey E.; Barcos-Munoz, Loreto D.; Beaton, Rachael; Bittle, Lauren; Borish, Henry J.; Burkhardt, Andrew; Corby, Joanna; Dean, Janice; Hancock, Danielle; King, Jennie; Prager, Brian; Romero, Charles; Sokal, Kimberly R.; Stierwalt, Sabrina; Wenger, Trey; Zucker, Catherine

    2015-01-01

    Now entering our sixth year of operation, Dark Skies, Bright Kids (DSBK) is an entirely volunteer-run outreach organization based out of the Department of Astronomy at the University of Virginia. Our core mission is to enhance elementary science education and literacy in central Virginia through fun, hands-on activities that introduce basic Astronomy concepts beyond Virginia's Standards of Learning. Our primary focus is hosting an 8-10 week after-school astronomy club at underserved elementary and middle schools. Each week, DSBK volunteers take the role of coaches to introduce astronomy-related concepts ranging from the Solar System to galaxies to astrobiology, and to lead students in interactive learning activities. Another hallmark of DSBK is hosting our Annual Central Virginia Star Party, a free event open to the community featuring star-gazing and planetarium shows.DSBK has amassed over 15,000 contact hours since 2009 and we continue to broaden our impact. One important step we have taken in the past year is to establish a graduate student led assessment program to identify and implement directed learning goals for DSBK outreach. The collection of student workbooks, observations, and volunteer surveys indicates broad scale success for the program both in terms of student learning and their perception of science. The data also reveal opportunities to improve our organizational and educational practices to maximize student achievement and overall volunteer satisfaction for DSBK's future clubs and outreach endeavors.

  15. Magnetic flux supplement to coronal bright points

    CERN Document Server

    Mou, Chaozhou; Xia, Lidong; Madjarska, Maria S; Li, Bo; Fu, Hui; Jiao, Fangran; Hou, Zhenyong

    2015-01-01

    Coronal bright points (BPs) are associated with magnetic bipolar features (MBFs) and magnetic cancellation. Here, we investigate how BP-associated MBFs form and how the consequent magnetic cancellation occurs. We analyse longitudinal magnetograms from the Helioseismic and Magnetic Imager to investigate the photospheric magnetic flux evolution of 70 BPs. From images taken in the 193 A passband of the Atmospheric Imaging Assembly (AIA) we dermine that the BPs' lifetimes vary from 2.7 to 58.8 hours. The formation of the BP MBFs is found to involve three processes, namely emergence, convergence and local coalescence of the magnetic fluxes. The formation of a MBF can involve more than one of these processes. Out of the 70 cases, flux emergence is the main process of a MBF buildup of 52 BPs, mainly convergence is seen in 28, and 14 cases are associated with local coalescence. For MBFs formed by bipolar emergence, the time difference between the flux emergence and the BP appearance in the AIA 193 \\AA\\ passband varie...

  16. Intrinsic brightness temperatures of blazar jets at 15 GHz

    Directory of Open Access Journals (Sweden)

    Hovatta Talvikki

    2013-12-01

    Full Text Available We have developed a new Bayesian Markov Chain Monte Carlo method to deconvolve light curves of blazars into individual flares, including proper estimation of the fit errors. We use the method to fit 15GHzlight curves obtained within the OVRO 40-m blazar monitoring program where a large number of AGN have been monitored since 2008 in support of the Fermi Gamma-Ray Space Telescope mission. The time scales obtained from the fitted models are used to calculate the variability brightness temperature of the sources. Additionally, we have calculated brightness temperatures of a sample of these objects using Very Long Baseline Array data from the MOJAVE survey. Combining these two data sets enables us to study the intrinsic brightness temperature distribution in these blazars at 15 GHz. Our preliminary results indicate that the mean intrinsic brightness temperature in a sample of 14 sources is near the equipartition brightness temperature of ~ 1011K.

  17. Nanoluciferase signal brightness using furimazine substrates opens bioluminescence resonance energy transfer to widefield microscopy.

    Science.gov (United States)

    Kim, Jiho; Grailhe, Regis

    2016-08-01

    Fluorescence and bioluminescence resonance energy transfer (FRET, BRET) techniques are powerful tools for studying protein-protein interactions in cellular assays. In contrast to fluorescent proteins, chemiluminescent proteins do not require excitation light, known to trigger autofluorescence, phototoxicity, and photobleaching. Regrettably, low signal intensity of luciferase systems restricts their usage as they require specialized microscopes equipped with ultra low-light imaging cameras. In this study, we report that bioluminescence quantification in living cells using a standard widefield automated microscope dedicated to screening and high content analysis is possible with the newer luciferase systems, Nanoluciferase (Nluc). With such equipment, we showed that robust intramolecular BRET can be measured using a combination of Nluc and yellow fluorescent protein (YFP). Using the human Superoxide Dismutase 1 (SOD1) dimer model, we next validated that intermolecular BRET could be quantified at a single cell level. The enhanced signal brightness of Nluc enabling BRET imaging to widefield microscopy shows strong potential to open up single cell protein-protein interactions studies to a wider audience. © 2016 International Society for Advancement of Cytometry. PMID:27144967

  18. Dark Skies, Bright Kids: Year 2

    Science.gov (United States)

    Carlberg, Joleen K.; Johnson, K.; Lynch, R.; Walker, L.; Beaton, R.; Corby, J.; de Messieres, G.; Drosback, M.; Gugliucci, N.; Jackson, L.; Kingery, A.; Layman, S.; Murphy, E.; Richardson, W.; Ries, P.; Romero, C.; Sivakoff, G.; Sokal, K.; Trammell, G.; Whelan, D.; Yang, A.; Zasowski, G.

    2011-01-01

    The Dark Skies, Bright Kids (DSBK) outreach program brings astronomy education into local elementary schools in central Virginia's Southern Albemarle County through an after-school club. Taking advantage of the unusually dark night skies in the rural countryside, DSBK targets economically disadvantaged schools that tend to be underserved due to their rural locale. The goals of DSBK are to foster children's natural curiosity, demonstrate that science is a fun and creative process, challenge students' conceptions of what a scientist is and does, and teach some basic astronomy. Furthermore, DSBK works to assimilate families into students' education by holding family observing nights at the school. Now in its third semester, DSBK has successfully run programs at two schools with very diverse student populations. Working with these students has helped us to revise our activities and to create new ones. A by-product of our work has been the development of lesson plans, complete with learning goals and detailed instructions, that we make publically available on our website. This year we are expanding our repertoire with our new planetarium, which allows us to visualize topics in novel ways and supplements family observing on cloudy nights. The DSBK volunteers have also created a bilingual astronomy artbook --- designed, written, and illustrated by UVa students --- that we will publish and distribute to elementary schools in Virginia. Our book debuted at the last AAS winter meeting, and since then it has been extensively revised and updated with input from many individuals, including parents, professional educators, and a children's book author. Because the club is currently limited to serving a few elementary schools, this book will be part of our efforts to broaden our impact by bringing astronomy to schools we cannot go to ourselves and reaching out to Spanish-speaking communities at the same time.

  19. Dark Skies, Bright Kids! Year 3

    Science.gov (United States)

    Whelan, David G.; Johnson, K. E.; Barcos-Munoz, L. D.; Beaton, R. L.; Borish, J.; Corby, J. F.; Dorsey, G.; Gugliucci, N. E.; Prager, B. J.; Ries, P. A.; Romero, C. E.; Sokal, K. R.; Tang, X.; Walker, L. M.; Yang, A. J.; Zasowski, G.

    2012-01-01

    Dark Skies, Bright Kids! (DSBK) is a program that brings astronomy education to elementary schools throughout central Virginia. In a relaxed, out-of-classroom atmosphere, we are able to foster the innate curiosity that young students have about science and the world around them. We target schools that are under-served due to their rural locale or special needs students, demonstrating that science is a fun and creative process to a segment of the population that might not otherwise be exposed to astronomy. Families are included in the learning experience during semi-annual `star parties'. Since last January, we have expanded the breadth and depth of our educational capabilities. We have developed new programs for use in our digital planetarium. We held the first Central Virginia Star Party, providing an atmosphere where local children from multiple schools were able to share their love for astronomy. Local government and University officials were also invited so that they could experience our focused science outreach. Most recently, we have become part of Ivy Creek School's Club Day activities, bringing our program to a new segment of the elementary school system in Albemarle County: those that have `low-incidence' disabilities, requiring special attention. We continue to develop a curriculum for after-school programs that functions as either a series of one-time activities or several months of focused outreach at one school. Many of these activities are provided on our website, http://www.astro.virginia.edu/dsbk/, for the wider astronomical community, including the new planetarium work. We have extended our book project to include two bilingual astronomy books called `Snapshots of the Universe,' one in Spanish and English, the other in French and English. These books introduce young people to some of the many wonders of the Universe through art and captions developed by DSBK volunteers.

  20. Dark Skies, Bright Kids! Year 5

    Science.gov (United States)

    Prager, Brian; Johnson, K. E.; Barcos-Munoz, L. D.; Beaton, R.; Bittle, L.; Borish, H.; Burkhardt, A.; Corby, J.; Damke, G.; Dean, J.; Dorsey, G.; Graninger, D.; Lauck, T.; Liss, S.; Oza, A.; Peacock, S.; Romero, C.; Sokal, K. R.; Stierwalt, S.; Walker, L.; Wenger, T.; Zucker, C.

    2014-01-01

    Our public outreach group Dark Skies, Bright Kids! (DSBK) fosters science literacy in Virginia by bringing a hands-on approach to astronomy that engages children's natural excitement and curiosity. We are an entirely volunteer-run group based out of the Department of Astronomy at the University of Virginia and we enthusiastically utilize astronomy as a 'gateway science.' We create long-term relationships with students during an 8 to 10 week long, after-school astronomy club at under served elementary schools in neighboring counties, and we visited 3 different schools in 2013. Additionally, we organize and participate in science events throughout the community. The fifth year of DSBK was marked by surpassing 10,000 contact hours in Spring 2013 Semester and by ringing in the fall semester with our biggest, most successful star party to date. We hosted the Third Annual Central Virginia Star Party, free and open to the community to encourage families to enjoy astronomy together. Nearly four hundred people of all ages attended, double the number from previous years. Joining with local astronomical societies, we offered an enlightening and exciting night with resources rarely accessible to the public, such as an IR camera and a portable planetarium. With numerous telescopes pointed at the sky, and a beautifully clear night with views of the Milky Way, the International Space Station, and numerous meteors, the star party was a fantastic opportunity to introduce many of our guests to the natural wonders of our night sky and enjoy some of the darkest skies on the eastern seaboard.

  1. Dark Skies, Bright Kids! Year 4

    Science.gov (United States)

    Sokal, Kimberly R.; Johnson, K. E.; Barcos-Munoz, L. D.; Beaton, R.; Borish, J.; Crawford, S. B.; Corby, J.; Damke, G.; Dean, J.; Dorsey, G.; Jackson, L.; Liss, S.; Oza, A.; Peacock, S.; Prager, B.; Romero, C.; Sivakoff, G. R.; Walker, L.; Whelan, D. G.; Zucker, C.

    2013-01-01

    Aiming to engage young children's natural excitement and curiosity, the outreach group Dark Skies, Bright Kids (DSBK) brings a hands-on approach to astronomy to elementary schools in Virginia. We hope to enhance children's view and understanding of science while exploring the Universe using fun activities. DSBK focuses on rural and underserved schools in Albemarle County and offers a semester-long astronomy club for third through fifth grade students. We believe regular interactions foster personal relationships between students and volunteers that encourage a life-long interest in science. In our fourth year of hosting clubs, we returned to Ivy Creek Elementary School, where we saw wonderful responses from a special group of students with `low-incidence' disabilities. DSBK has grown to realize a broader reach beyond local astronomy clubs; we hope to ignite a spark of interest in astronomy and science more widely- in more children, their families, and their teachers. We also hosted the Second Annual Central Virginia Star Party with an open invitation to the community to encourage families to enjoy astronomy together. Throughout the year, DSBK now holds 'one-off' programs (akin to astronomy field days) for elementary schools and children's groups throughout Virginia. Furthermore, we are in the final stages of a project to create two bilingual astronomy books called "Snapshots of the Universe", in Spanish and French with English translations. This art book will be made available online and we are working to get a copy in every elementary school in the state. DSBK has begun to reach out to elementary school teachers in order to provide them with useful and engaging classroom material. We have adapted our volunteer-created activities into useful and ready-to-use lessons, available online. After improvements based on research through interactions and feedback from teachers, we have explicitly identified the learning goals in terms of Virginia's Standards of Learning

  2. Gd(iii)-doped carbon dots as a dual fluorescent-MRI probe

    KAUST Repository

    Bourlinos, Athanasios B.

    2012-01-01

    We describe the synthesis of Gd(iii)-doped carbon dots as dual fluorescence-MRI probes for biomedical applications. The derived Gd(iii)-doped carbon dots show uniform particle size (3-4 nm) and gadolinium distribution and form stable dispersions in water. More importantly, they exhibit bright fluorescence, strong T1-weighted MRI contrast and low cytotoxicity. © The Royal Society of Chemistry 2012.

  3. The use of fluorescence enhancement to improve the microscopic diagnosis of falciparum malaria

    OpenAIRE

    Liu Paul; Guy Rebecca; Pennefather Peter; Crandall Ian

    2007-01-01

    Abstract Background Giemsa staining of thick blood smears remains the "gold standard" for detecting malaria. However, this method is not very good for diagnosing low-level infections. A method for the simultaneous staining of Plasmodium-parasitized culture and blood smears for both bright field and fluorescence was developed and its ability to improve detection efficiency tested. Methods A total of 22 nucleic acid-specific fluorescent dyes were tested for their ability to provide easily obser...

  4. The lowest spatial frequency channel determines brightness perception.

    Science.gov (United States)

    Perna, A; Morrone, M C

    2007-05-01

    This study investigates the role played by individual spatial scales in determining the apparent brightness of greyscale patterns. We measured the perceived difference in brightness across an edge in the presence of notch filtering and high-pass filtering for two stimulus configurations, one that elicits the perception of transparency and one that appears opaque. For both stimulus configurations, the apparent brightness of the surfaces delimited by the border decreased monotonically with progressive (ideal) high-pass filtering, with a critical cut-off at 1 c/deg. Using two octave ideal notch filtering, the maximum detrimental effect on apparent brightness was observed at about 1c/deg. Critical frequencies for apparent brightness did not vary with contrast, viewing distance, or surface size, suggesting that apparent brightness is determined by the channel tuned at 1 c/deg. Modelling the data with the local energy model [Morrone, M. C., & Burr, D. C. (1988). Feature detection in human vision: a phase dependent energy model. Proceedings of the Royal Society (London), B235, 221-245] at 1c/deg confirmed the suggestion that this channel mediates apparent brightness for both opaque and transparent borders, with no need for pooling or integration across spatial channels. PMID:17395237

  5. Brightness of synchrotron radiation from undulators and bending magnets

    International Nuclear Information System (INIS)

    We consider the maximum of the Wigner distribution (WD) of synchrotron radiation (SR) fields as a possible definition of SR source brightness. Such figure of merit was originally introduced in the SR community by Kim. The brightness defined in this way is always positive and, in the geometrical optics limit, can be interpreted as maximum density of photon flux in phase space. For undulator and bending magnet radiation from a single electron, the WD function can be explicitly calculated. In the case of an electron beam with a finite emittance the brightness is given by the maximum of the convolution of a single electron WD function and the probability distribution of the electrons in phase space. In the particular case when both electron beam size and electron beam divergence dominate over the diffraction size and the diffraction angle, one can use a geometrical optics approach. However, there are intermediate regimes when only the electron beam size or the electron beam divergence dominate. In this asymptotic cases the geometrical optics approach is still applicable, and the brightness definition used here yields back once more the maximum photon flux density in phase space. In these intermediate regimes we find a significant numerical disagreement between exact calculations and the approximation for undulator brightness currently used in literature. We extend the WD formalism to a satisfactory theory for the brightness of a bending magnet. We find that in the intermediate regimes the usually accepted approximation for bending magnet brightness turns out to be inconsistent even parametrically.

  6. Near infrared fluorescent biliproteins generated from bacteriophytochrome AphB of Nostoc sp. PCC 7120.

    Science.gov (United States)

    Yuan, Che; Li, Hui-Zhen; Tang, Kun; Gärtner, Wolfgang; Scheer, Hugo; Zhou, Ming; Zhao, Kai-Hong

    2016-04-13

    The genome of the cyanobacterium Nostoc sp. PCC 7120 encodes a large number of putative bacteriophytochrome and cyanobacteriochrome photoreceptors that, due to their long-wavelength absorption and fluorescence emission, might serve as fluorescent tags in intracellular investigations. We show that the PAS-GAF domain of the bacteriophytochrome, AphB, binds biliverdin covalently and exhibits, besides its reversible photochemistry, a moderate fluorescence in the near infrared (NIR) spectral region. It was selected for further increasing the brightness while retaining the NIR fluorescence. In the first step, amino acids assumed to improve fluorescence were selectively mutated. The resulting variants were then subjected to several rounds of random mutagenesis and screened for enhanced fluorescence in the NIR. The brightness of optimized PAS-GAF variants increased more than threefold compared to that of wt AphB(1-321), with only insignificant spectral shifts (Amax around 695 nm, and Fmax around 720 nm). In general, the brightness increases with decreasing wavelengths, which allows for a selection of the fluorophore depending on the optical properties of the tissue. A spectral heterogeneity was observed when residue His260, located in close proximity to the chromophore, was mutated to Tyr, emphasizing the strong effects of the environment on the electronic properties of the bound biliverdin chromophore. PMID:27004456

  7. Common fluorescent proteins for single-molecule localization microscopy

    Science.gov (United States)

    Klementieva, Natalia V.; Bozhanova, Nina G.; Mishina, Natalie M.; Zagaynova, Elena V.; Lukyanov, Konstantin A.; Mishin, Alexander S.

    2015-07-01

    Super-resolution techniques for breaking the diffraction barrier are spread out over multiple studies nowadays. Single-molecule localization microscopy such as PALM, STORM, GSDIM, etc allow to get super-resolved images of cell ultrastructure by precise localization of individual fluorescent molecules via their temporal isolation. However, these methods are supposed the use of fluorescent dyes and proteins with special characteristics (photoactivation/photoconversion). At the same time, there is a need for retaining high photostability of fluorophores during long-term acquisition. Here, we first showed the potential of common red fluorescent protein for single-molecule localization microscopy based on spontaneous intrinsic blinking. Also, we assessed the effect of different imaging media on photobleaching of these fluorescent proteins. Monomeric orange and red fluorescent proteins were examined for stochastic switching from a dark state to a bright fluorescent state. We studied fusions with cytoskeletal proteins in NIH/3T3 and HeLa cells. Imaging was performed on the Nikon N-STORM system equipped with EMCCD camera. To define the optimal imaging conditions we tested several types of cell culture media and buffers. As a result, high-resolution images of cytoskeleton structure were obtained. Essentially, low-intensity light was sufficient to initiate the switching of tested red fluorescent protein reducing phototoxicity and provide long-term live-cell imaging.

  8. Lamp spectrum and spatial brightness at photopic levels

    DEFF Research Database (Denmark)

    Fotios, Steve; Atli, Deniz; Cheal, Chris; Houser, Kevin; Logadóttir, Ásta

    2015-01-01

    lower illuminance with potential reductions in energy consumption. Consideration of experimental design was used to review 70 studies of spatial brightness. Of these, the 19 studies considered to provide credible evidence of SPD effects were used to explore metrics for predicting the effect of SPD but......Light sources are available in a variety of spectral power distributions (SPDs) and this affects spatial brightness in a manner not predicted by quantities such as illuminance. Tuning light source SPD to better match the sensitivity of visual perception may allow the same spatial brightness but at...

  9. First magnitude a book of the bright sky

    CERN Document Server

    Kaler, James B

    2012-01-01

    "First Magnitude" is an entry-level book for readers with brightly lit skies. Its purpose is to show them that all is not lost, that they can still enjoy personal astronomy and have an appreciation of the heavens no matter where they live. It concentrates on the Sun, Moon, the five bright planets, and on the 23 brightest stars, which are visible from just about anywhere. The book concludes with bright ephemeral phenomena: meteors, comets, and exploding stars. The concept is a platform for introducing the reader to the wonders of the nighttime and daytime skies and serves as an introduction to

  10. Fluorescent fiber diagnostics

    Science.gov (United States)

    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 ).

  11. Lyα EMISSION FROM COSMIC STRUCTURE. I. FLUORESCENCE

    International Nuclear Information System (INIS)

    We present predictions for the fluorescent Lyα emission signature arising from photoionized, optically thick structures in smoothed particle hydrodynamic cosmological simulations of a ΛCDM universe using a Monte Carlo Lyα radiative transfer code. We calculate the expected Lyα image and two-dimensional spectra for gas exposed to a uniform ultraviolet ionizing background as well as gas exposed additionally to the photoionizing radiation from a local quasar, after correcting for the self-shielding of hydrogen. As a test of our numerical methods and for application to current observations, we examine simplified analytic structures that are uniformly or anisotropically illuminated. We compare these results with recent observations. We discuss future observing campaigns on large telescopes and realistic strategies for detecting fluorescence owing to the ambient metagalactic ionization and in regions close to bright quasars. While it will take hundreds of hours on the current generation of telescopes to detect fluorescence caused by the ultraviolet background alone, our calculations suggest that on the order of 10 sources of quasar-induced fluorescent Lyα emission should be detectable after a 10 hr exposure in a 10 arcmin2 field around a bright quasar. These observations will help probe the physical conditions in the densest regions of the intergalactic medium as well as the temporal light curves and isotropy of quasar radiation.

  12. Hubble ultra deep field object surface brightness variation

    International Nuclear Information System (INIS)

    The technique of adjacent pixel brightness variation in log scale was applied to ultra deep field objects captured by the Hubble telescope. The local surface brightness fluctuation has a Gaussian-like distribution implying a random accretion of material, with collisions, as a random-walk motion. The larger fluctuation of log brightness in the mid to outer regions of some galaxies is consistent with the presence of dark matter. The absence of such fluctuation enhancement in two i-drop candidates at z ∼ 3 may mean that some dark matter is the result of nucleosynthesis in the evolution process. Large fluctuation in the B+V bands in contrast to the i+z band near the center in an i-drop candidate at z ∼ 3 was interpreted to be an AGN center. The distribution average shifts towards zero for more spiral galaxies, signifying the use of local surface brightness fluctuation distribution as a morphology parameter

  13. Operational Bright-Band Snow Level Detection Using Doppler Radar

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A method to detect the bright-band snow level from radar reflectivity and Doppler vertical velocity data collection with an atmospheric profiling Doppler radar. The...

  14. SMEX03 SSM/I Brightness Temperature Data, Georgia

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides brightness temperature data acquired during the Soil Moisture Experiment 2003 (SMEX03) by the Special Sensor Microwave/Imager (SSM/I). The...

  15. SMEX03 SSM/I Brightness Temperature Data, Brazil

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides brightness temperature data acquired during the Soil Moisture Experiment 2003 (SMEX03) by the Special Sensor Microwave/Imager (SSM/I). The...

  16. An observational correlation between stellar brightness variations and surface gravity

    CERN Document Server

    Bastien, Fabienne A; Basri, Gibor; Pepper, Joshua

    2013-01-01

    Surface gravity is one of a star's basic properties, but it is difficult to measure accurately, with typical uncertainties of 25-50 per cent if measured spectroscopically and 90-150 per cent photometrically. Asteroseismology measures gravity with an uncertainty of about two per cent but is restricted to relatively small samples of bright stars, most of which are giants. The availability of high-precision measurements of brightness variations for >150,000 stars provides an opportunity to investigate whether the variations can be used to determine surface gravities. The Fourier power of granulation on a star's surface correlates physically with surface gravity; if brightness variations on timescales of hours arise from granulation, then such variations should correlate with surface gravity. Here we report an analysis of archival data that reveals an observational correlation between surface gravity and the root-mean-square brightness variations on timescales of less than eight hours for stars with temperatures ...

  17. Brightness, coherence, and propagation characteristics of synchrotron radiation

    International Nuclear Information System (INIS)

    A formalism is presented by means of which the propagation and imaging characteristics of synchrotron radiation can be studied, taking into account the effects of diffraction, electron beam emittance, and the transverse and longitudinal extent of the source. An important quantity in this approach is the Wigner distribution of the electric fields, which can be interpreted as a phase-space distribution of photon flux, and thus can be identified with the brightness. When integrated over the angular variables, the brightness becomes the intensity distribution in the spatial variables and when integrated over the spatial variables, it becomes the intensity distribution in angular variables. The brightness so defined transforms through a general optical medium in exactly the same way as in the case of a collection of geometric rays. Finally, the brightness of different electrons adds in a simple way. Optical characteristics of various synchrotron radiation sources - bending magnets, wigglers and undulators, are analyzed using this formalism

  18. Ultra High Brightness/Low Cost Fiber Coupled Packaging Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The focus of the proposed effort is maximizing the brightness of fiber coupled laser diode pump sources at a minimum cost. The specific innovation proposed is to...

  19. Visible Color and Photometry of Bright Materials on Vesta

    Science.gov (United States)

    Schroder, S. E.; Li, J. Y.; Mittlefehldt, D. W.; Pieters, C. M.; De Sanctis, M. C.; Hiesinger, H.; Blewett, D. T.; Russell, C. T.; Raymond, C. A.; Keller, H. U.

    2012-01-01

    The Dawn Framing Camera (FC) collected images of the surface of Vesta at a pixel scale of 70 m in the High Altitude Mapping Orbit (HAMO) phase through its clear and seven color filters spanning from 430 nm to 980 nm. The surface of Vesta displays a large diversity in its brightness and colors, evidently related to the diverse geology [1] and mineralogy [2]. Here we report a detailed investigation of the visible colors and photometric properties of the apparently bright materials on Vesta in order to study their origin. The global distribution and the spectroscopy of bright materials are discussed in companion papers [3, 4], and the synthesis results about the origin of Vestan bright materials are reported in [5].

  20. Are solar brightness variations faculae- or spot-dominated?

    CERN Document Server

    Shapiro, A I; Krivova, N A; Yeo, K L; Schmutz, W K

    2016-01-01

    Regular spaceborne measurements have revealed that solar brightness varies on multiple timescales, variations on timescales greater than a day being attributed to surface magnetic field. Independently, ground-based and spaceborne measurements suggest that Sun-like stars show a similar, but significantly broader pattern of photometric variability. To understand whether the broader pattern of stellar variations is consistent with the solar paradigm we assess relative contributions of faculae and spots to solar magnetically-driven brightness variability. We investigate how the solar brightness variability as well as its facular and spot contributions depend on the wavelength, timescale of variability, and position of the observer relative to the ecliptic plane. We perform calculations with the SATIRE model, which returns solar brightness with daily cadence from solar disc area coverages of various magnetic features. Moving the observer away from the ecliptic plane increases the amplitude of 11-year variability a...

  1. Fluorescent minerals, a review

    Science.gov (United States)

    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

  2. Millimeter-wave brightness temperatures of military vehicles

    Science.gov (United States)

    Nemarich, Joseph; Cassidy, Thomas W.; Shiner, R.; Agravante, Hiroshi H.; Dixon, David; Moffa, Philip; Quon, Bill H.; Yujiri, Larry; Dahlstrom, R.

    1999-07-01

    Millimeter wave (MMW) radiometers operating at 97 and 140 GHz were used to obtain passive MMW images and brightness temperatures of military vehicles at various altitudes and depression angles. The line-scanning radiometer system used for the measurements is described, and several passive MMW images are presented. The upper-bound MMW brightness temperatures of a number of different types of vehicles in an open area were determined and shown to have similar values at various depression angles.

  3. Night Sky Brightness and Light Pollution in Comunidad de Madrid

    OpenAIRE

    Zamorano Calvo, Jaime; Sánchez de Miguel, Alejandro; Gómez Castaño, José; Ocaña González, Francisco; Gallego Maestro, Jesús; Pila Díez, Berenice; Nievas Rosillo, Miguel; Tapia Ayuga, Carlos; Fernández Domínguez, Alberto; Pascual Ramírez, Sergio

    2013-01-01

    Preliminary results of a study of the night sky background brightness around the city of Madrid using Sky Quality Meter (SQM) photometers are presented. Data-retrieval methodology includes an automatic procedure to measure from a moving vehicle which allows to speed up the data gathering. The night sky brightness, an astronomical quality parameter that accounts for luminous flux from the sky, is closely related with the light pollution. The map with the spatial distribution of the night s...

  4. Analytically derived conversion of spectral band radiance to brightness temperature

    Energy Technology Data Exchange (ETDEWEB)

    Berk, Alexander [Spectral Sciences, Inc., 44th Avenue, Burlington, MA 01803 (United States)], E-mail: lex@spectral.com

    2008-05-15

    Simple analytic expressions for brightness temperature have been derived in terms of band response function spectral moments. Accuracy measures are also derived. Application of these formulas to GOES-12 Sounder thermal infrared bands produces brightness temperature residuals between -5.0 and 2.5 mK for a 150-400 K temperature range. The magnitude of residuals for the five ASTER Radiometer thermal infrared bands over the same temperature range is less than 0.22 mK.

  5. Facial Expression Recognition using Entropy and Brightness Features

    OpenAIRE

    Khan, Rizwan Ahmed; Meyer, Alexandre; Konik, Hubert; Bouakaz, Saïda

    2011-01-01

    International audience This paper proposes a novel framework for universal facial expression recognition. The framework is based on two sets of features extracted from the face image: entropy and brightness. First, saliency maps are obtained by state-of-the-art saliency detection algorithm i.e. "frequencytuned salient region detection". Then only localized salient facial regions from saliency maps are processed to extract entropy and brightness features. To validate the performance of sali...

  6. New Low Surface Brightness Dwarf Galaxies Detected Around Nearby Spirals

    OpenAIRE

    Karachentsev, I. D.; Riepe, P.; Zilch, T.; Blauensteiner, M.; Elvov, M.; Hochleitner, P.; Hubl, B.; Kerschhuber, G.; Küppers, S.; Neyer, F.; Pölzl, R.; Remmel, P.; Schneider, O.; Sparenberg, R.; Trulson, U.

    2015-01-01

    We conduct a survey of low surface brightness (LSB) satellite galaxies around the Local Volume massive spirals using long exposures with small amateur telescopes. We identified 27 low and very low surface brightness objects around the galaxies NGC,672, 891, 1156, 2683, 3344, 4258, 4618, 4631, and 5457 situated within 10 Mpc from us, and found nothing new around NGC,2903, 3239, 4214, and 5585. Assuming that the dwarf candidates are the satellites of the neighboring luminous galaxies, their abs...

  7. Bright-field Nanoscopy: Visualizing Nano-structures with Localized Optical Contrast Using a Conventional Microscope

    Science.gov (United States)

    Suran, Swathi; Bharadwaj, Krishna; Raghavan, Srinivasan; Varma, Manoj M.

    2016-04-01

    Most methods for optical visualization beyond the diffraction limit rely on fluorescence emission by molecular tags. Here, we report a method for visualization of nanostructures down to a few nanometers using a conventional bright-field microscope without requiring additional molecular tags such as fluorophores. The technique, Bright-field Nanoscopy, is based on the strong thickness dependent color of ultra-thin germanium on an optically thick gold film. We demonstrate the visualization of grain boundaries in chemical vapour deposited single layer graphene and the detection of single 40 nm Ag nanoparticles. We estimate a size detection limit of about 2 nm using this technique. In addition to visualizing nano-structures, this technique can be used to probe fluid phenomena at the nanoscale, such as transport through 2D membranes. We estimated the water transport rate through a 1 nm thick polymer film using this technique, as an illustration. Further, the technique can also be extended to study the transport of specific ions in the solution. It is anticipated that this technique will find use in applications ranging from single-nanoparticles resolved sensing to studying nanoscale fluid-solid interface phenomena.

  8. Rapid identification of microorganisms by intrinsic fluorescence

    Science.gov (United States)

    Bhatta, Hemant; Goldys, Ewa M.; Learmonth, Robert

    2005-03-01

    Microbial contamination has serious consequences for the industries that use fermentation processes. Common contaminants such as faster growing lactic acid bacteria or wild yeast can rapidly outnumber inoculated culture yeast and produce undesirable end products. Our study focuses on a rapid method of identification of such contaminants based on autofluorescence spectroscopy of bacterial and yeast species. Lactic acid bacteria (Lac-tobacillus casei), and yeast (Saccharomyces cerevisiae) were cultured under controlled conditions and studied for variations in their autofluorescence. We observed spectral differences in the spectral range representative of tryptophan residues of proteins, with excitation at 290 nm and emission scanned in the 300 nm - 440 nm range. Excitation scans between 240 nm and 310 nm were also performed for the emission at 340 nm. Moreover, we observed clearly pronounced differences in the excitation and emission in the visible range, with 410 nm excitation. These results demonstrate that bacterial and yeast species can be differentiated using their intrinsic fluorescence both in UV and in the visible region. The comparative spectroscopic study of selected strains of Saccharomyces yeast showed clear differences between strains. Spectrally-resolved laser scanning microscopy was carried out to link the results obtained using ensembles of cells with spectral properties of individual cells. Strongly fluorescent subpopulation were observed for all yeast strains with excitation at 405 nm. The fluorescence spectra showed variations correlated with cell brightness. The presented results demonstrate that using autofluorescence, it is possible to differentiate between yeast and lactic acid bacteria and between different yeast species.

  9. Fluorescent lighting with aluminum nitride phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Cherepy, Nerine J.; Payne, Stephen A.; Seeley, Zachary M.; Srivastava, Alok M.

    2016-05-10

    A fluorescent lamp includes a glass envelope; at least two electrodes connected to the glass envelope; mercury vapor and an inert gas within the glass envelope; and a phosphor within the glass envelope, wherein the phosphor blend includes aluminum nitride. The phosphor may be a wurtzite (hexagonal) crystalline structure Al.sub.(1-x)M.sub.xN phosphor, where M may be drawn from beryllium, magnesium, calcium, strontium, barium, zinc, scandium, yttrium, lanthanum, cerium, praseodymium, europium, gadolinium, terbium, ytterbium, bismuth, manganese, silicon, germanium, tin, boron, or gallium is synthesized to include dopants to control its luminescence under ultraviolet excitation. The disclosed Al.sub.(1-x)M.sub.xN:Mn phosphor provides bright orange-red emission, comparable in efficiency and spectrum to that of the standard orange-red phosphor used in fluorescent lighting, Y.sub.2O.sub.3:Eu. Furthermore, it offers excellent lumen maintenance in a fluorescent lamp, and does not utilize "critical rare earths," minimizing sensitivity to fluctuating market prices for the rare earth elements.

  10. Synthesizing SMOS Zero-Baselines with Aquarius Brightness Temperature Simulator

    Science.gov (United States)

    Colliander, A.; Dinnat, E.; Le Vine, D.; Kainulainen, J.

    2012-01-01

    SMOS [1] and Aquarius [2] are ESA and NASA missions, respectively, to make L-band measurements from the Low Earth Orbit. SMOS makes passive measurements whereas Aquarius measures both passive and active. SMOS was launched in November 2009 and Aquarius in June 2011.The scientific objectives of the missions are overlapping: both missions aim at mapping the global Sea Surface Salinity (SSS). Additionally, SMOS mission produces soil moisture product (however, Aquarius data will eventually be used for retrieving soil moisture too). The consistency of the brightness temperature observations made by the two instruments is essential for long-term studies of SSS and soil moisture. For resolving the consistency, the calibration of the instruments is the key. The basis of the SMOS brightness temperature level is the measurements performed with the so-called zero-baselines [3]; SMOS employs an interferometric measurement technique which forms a brightness temperature image from several baselines constructed by combination of multiple receivers in an array; zero-length baseline defines the overall brightness temperature level. The basis of the Aquarius brightness temperature level is resolved from the brightness temperature simulator combined with ancillary data such as antenna patterns and environmental models [4]. Consistency between the SMOS zero-baseline measurements and the simulator output would provide a robust basis for establishing the overall comparability of the missions.

  11. Evolution of Bright Screening-photovoltaic Spatial Optical Solitons

    Institute of Scientific and Technical Information of China (English)

    LIU Jinsong

    2001-01-01

    A numerical analysis of the dynamical evolution of bright screening-photovoltaic (SP) spatial solitons in biased photovoltaic-photorefractive materials in the case of neglecting the material loss and the diffusion is presented. When an incident optical beam is a bright SP soliton, the beam propagates along a linear path with its shape kept unchanged. When the incident optical beam is slightly different from a bright SP soliton, the beam reshapes itself and tries to evolve into a bright SP soliton after a short distance. However, when the incident optical beam is significantly different from a SP bright soliton, the beam cannot evolve into a stable bright SP soliton, and tends to experience periodic compression and expansion. For a low-intensity input beam, the wave experiences a periodic process of compression first and then expansion during the initial part of the cycle. For a high-intensity input beam, however, the wave will initially diffract and then experiences compression during the cycle.

  12. Live-cell multiphoton fluorescence correlation spectroscopy with an improved large Stokes shift fluorescent protein

    Science.gov (United States)

    Guan, Yinghua; Meurer, Matthias; Raghavan, Sarada; Rebane, Aleksander; Lindquist, Jake R.; Santos, Sofia; Kats, Ilia; Davidson, Michael W.; Mazitschek, Ralph; Hughes, Thomas E.; Drobizhev, Mikhail; Knop, Michael; Shah, Jagesh V.

    2015-01-01

    We report an improved variant of mKeima, a monomeric long Stokes shift red fluorescent protein, hmKeima8.5. The increased intracellular brightness and large Stokes shift (∼180 nm) make it an excellent partner with teal fluorescent protein (mTFP1) for multiphoton, multicolor applications. Excitation of this pair by a single multiphoton excitation wavelength (MPE, 850 nm) yields well-separable emission peaks (∼120-nm separation). Using this pair, we measure homo- and hetero-oligomerization interactions in living cells via multiphoton excitation fluorescence correlation spectroscopy (MPE-FCS). Using tandem dimer proteins and small-molecule inducible dimerization domains, we demonstrate robust and quantitative detection of intracellular protein–protein interactions. We also use MPE-FCCS to detect drug–protein interactions in the intracellular environment using a Coumarin 343 (C343)-conjugated drug and hmKeima8.5 as a fluorescence pair. The mTFP1/hmKeima8.5 and C343/hmKeima8.5 combinations, together with our calibration constructs, provide a practical and broadly applicable toolbox for the investigation of molecular interactions in the cytoplasm of living cells. PMID:25877871

  13. Microwave heating of arginine yields highly fluorescent nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Philippidis, Aggelos [Foundation for Research and Technology-Hellas, Institute of Electronic Structure and Laser (Greece); Stefanakis, Dimitrios [University of Crete, Department of Chemistry (Greece); Anglos, Demetrios, E-mail: anglos@iesl.forth.gr [Foundation for Research and Technology-Hellas, Institute of Electronic Structure and Laser (Greece); Ghanotakis, Demetrios, E-mail: ghanotakis@chemistry.uoc.gr [University of Crete, Department of Chemistry (Greece)

    2013-01-15

    Brightly fluorescent nanoparticles were produced via a single-step, single-precursor procedure based on microwave heating of an aqueous solution of the amino acid arginine. Key structural and optical properties of the resulting Arg nanoparticles, Arg-dots, are reported and discussed with emphasis on the pH dependence of their fluorescence emission. The surface of the Arg-dots was functionalised through coupling to folic acid, opening up ways for connecting fluorescent nanoparticles to cancer cells. The generality and versatility of the microwave heating procedure was further demonstrated by the synthesis of different types of carbon nanoparticles, such as CE-dots, that were produced by use of citric acid and ethanolamine as precursors and compared to the Arg-dots.

  14. Microwave heating of arginine yields highly fluorescent nanoparticles

    International Nuclear Information System (INIS)

    Brightly fluorescent nanoparticles were produced via a single-step, single-precursor procedure based on microwave heating of an aqueous solution of the amino acid arginine. Key structural and optical properties of the resulting Arg nanoparticles, Arg-dots, are reported and discussed with emphasis on the pH dependence of their fluorescence emission. The surface of the Arg-dots was functionalised through coupling to folic acid, opening up ways for connecting fluorescent nanoparticles to cancer cells. The generality and versatility of the microwave heating procedure was further demonstrated by the synthesis of different types of carbon nanoparticles, such as CE-dots, that were produced by use of citric acid and ethanolamine as precursors and compared to the Arg-dots.

  15. Two-photon directed evolution of green fluorescent proteins

    Science.gov (United States)

    Stoltzfus, Caleb R.; Barnett, Lauren M.; Drobizhev, Mikhail; Wicks, Geoffrey; Mikhaylov, Alexander; Hughes, Thomas E.; Rebane, Aleksander

    2015-07-01

    Directed evolution has been used extensively to improve the properties of a variety of fluorescent proteins (FPs). Evolutionary strategies, however, have not yet been used to improve the two-photon absorption (2PA) properties of a fluorescent protein, properties that are important for two-photon imaging in living tissues, including the brain. Here we demonstrate a technique for quantitatively screening the two-photon excited fluorescence (2PEF) efficiency and 2PA cross section of tens of thousands of mutant FPs expressed in E. coli colonies. We use this procedure to move EGFP through three rounds of two-photon directed evolution leading to new variants showing up to a 50% enhancement in peak 2PA cross section and brightness within the near-IR tissue transparency wavelength range.

  16. Out of the darkness and into the light: bright field in situ hybridisation for delineation of ERBB2 (HER2) status in breast carcinoma

    OpenAIRE

    Gruver, Aaron M; Peerwani, Ziad; Tubbs, Raymond R.

    2010-01-01

    Assessment of ERBB2 (HER2) status in breast carcinomas has become critical in determining response to the humanised monoclonal antibody trastuzumab. The current joint College of American Pathologists and the American Society of Clinical Oncology guidelines for the evaluation of HER2 status in breast carcinoma involve testing by immunohistochemistry and fluorescence in situ hybridisation (FISH). However, neither of these modalities is without limitations. Novel bright field in situ hybridisati...

  17. Giant Amplification of Photoswitching by a Few Photons in Fluorescent Photochromic Organic Nanoparticles.

    Science.gov (United States)

    Su, Jia; Fukaminato, Tuyoshi; Placial, Jean-Pierre; Onodera, Tsunenobu; Suzuki, Ryuju; Oikawa, Hidetoshi; Brosseau, Arnaud; Brisset, François; Pansu, Robert; Nakatani, Keitaro; Métivier, Rémi

    2016-03-01

    Controlling or switching the optical signal from a large collection of molecules with the minimum of photons represents an extremely attractive concept. Promising fundamental and practical applications may be derived from such a photon-saving principle. With this aim in mind, we have prepared fluorescent photochromic organic nanoparticles (NPs), showing bright red emission, complete ON-OFF contrast with full reversibility, and excellent fatigue resistance. Most interestingly, upon successive UV and visible light irradiation, the NPs exhibit a complete fluorescence quenching and recovery at very low photochromic conversion levels (photochromic molecule. This "giant amplification of fluorescence photoswitching" originates from efficient intermolecular energy-transfer processes within the NPs. PMID:26821998

  18. Seoul National University Bright Quasar Survey in Optical (SNUQSO). II. Discovery of 40 Bright Quasars Near the Galactic Plane

    CERN Document Server

    Im, Myungshin; Cho, Yunseok; Choi, Changsu; Ko, Jongwan; Song, Mimi

    2008-01-01

    We report the discovery of 40 bright quasars and active galactic nuclei (AGNs) at low Galactic latitude (b<20deg). The low Galactic latitude region has been considered a place to avoid when searching for extragalactic sources, because of the high Galactic extinction, as well as a large number of stars contaminating the sample selection. Bright quasars (R<~17) suffer more from such difficulties because they look like bright stars, which are numerous at low b, yet their surface number density is very low. In order to find quasars in this region of the sky less explored for extragalactic sources, we have started a survey of low Galactic latitude bright quasars as a part of the Seoul National University Quasar Survey in Optical (SNUQSO). Quasar candidates have been selected from radio and near-infrared (NIR) data. Out of 88 targets, we identify 29 bright quasars/AGNs around the antigalactic center, and 11 bright quasars/AGNs in the outskirts of the Galactic center, from two observing runs in 2006 at the Boh...

  19. Acri-2,7-Py, a bright red-emitting DNA probe identified through screening of a distyryl dye library.

    Science.gov (United States)

    Naud-Martin, Delphine; Martin-Benlloch, Xavier; Poyer, Florent; Mahuteau-Betzer, Florence; Teulade-Fichou, Marie-Paule

    2014-02-01

    The identification of DNA sensors is still a challenge since no DNA probe possesses all the photophysical properties required for live-cell imaging: high fluorescence yield, red emission, permeability, no photobleaching and no cytotoxicity. We describe the preparation of a distyryl dye library and its evaluation on a panel of nucleic acids with various structures (duplex DNA, quadruplex DNA and RNA). The screening involved measuring the modification of the fluorescence properties of the dyes with or without nucleic acids on a microplate reader, and allowed the identification of selective quadruplex DNA ligands with good affinities. Using this screening method we discovered a new bright red-emitting DNA stain, Acri-2,7-Py, for fixed cells. In living cells, the staining was not nuclear and photodamage generated through illumination induced cellular death. These processes require further studies to determine the relevance of Acri-2,7-Py in photodynamic therapy. PMID:24323895

  20. Fluorescence of atopic allergens

    NARCIS (Netherlands)

    Berrens, L.

    1967-01-01

    Purified atopic allergens have been found to emit flue fluorescence upon irradiation with ultraviolet light of 365 mμ wavelength. The maximum of fluorescence is in the region 445–490 mμ and the intensity is of the same order of magnitude for different atopic allergens. Synthetic model compounds, inc

  1. Membranes and Fluorescence microscopy

    DEFF Research Database (Denmark)

    Bagatolli, Luis

    2009-01-01

    Fluorescence spectroscopy-based techniques using conventional fluorimeters have been extensively applied since the late 1960s to study different aspects of membrane-related phenomena, i.e., mainly relating to lipid-lipid and lipid-protein (peptide) interactions. Even though fluorescence...

  2. A green fluorescent protein with photoswitchable emission from the deep sea.

    Directory of Open Access Journals (Sweden)

    Alexander Vogt

    Full Text Available A colorful variety of fluorescent proteins (FPs from marine invertebrates are utilized as genetically encoded markers for live cell imaging. The increased demand for advanced imaging techniques drives a continuous search for FPs with new and improved properties. Many useful FPs have been isolated from species adapted to sun-flooded habitats such as tropical coral reefs. It has yet remained unknown if species expressing green fluorescent protein (GFP-like proteins also exist in the darkness of the deep sea. Using a submarine-based and -operated fluorescence detection system in the Gulf of Mexico, we discovered ceriantharians emitting bright green fluorescence in depths between 500 and 600 m and identified a GFP, named cerFP505, with bright fluorescence emission peaking at 505 nm. Spectroscopic studies showed that approximately 15% of the protein bulk feature reversible ON/OFF photoswitching that can be induced by alternating irradiation with blue und near-UV light. Despite being derived from an animal adapted to essentially complete darkness and low temperatures, cerFP505 maturation in living mammalian cells at 37 degrees C, its brightness and photostability are comparable to those of EGFP and cmFP512 from shallow water species. Therefore, our findings disclose the deep sea as a potential source of GFP-like molecular marker proteins.

  3. Detecting clandestine material with nuclear resonance fluorescence

    Science.gov (United States)

    Pruet, J.; McNabb, D. P.; Hagmann, C. A.; Hartemann, F. V.; Barty, C. P. J.

    2006-06-01

    We study the performance of a class of interrogation systems that exploit nuclear resonance fluorescence (NRF) to detect specific isotopes. In these systems the presence of a particular nuclide is inferred by observing the preferential attenuation of photons that strongly excite an electromagnetic transition in that nuclide. Estimates for the false positive/negative error rates, radiological dose, and detection sensitivity associated with discovering clandestine material embedded in cargo are presented. The relation between performance of the detection system and properties of the beam of interrogating photons is also considered. Bright gamma-ray sources with fine energy and angular resolution, such as those based on Thomson upscattering of laser light, are found to be associated with uniquely low radiological dose, scan times, and error rates. For this reason a consideration of NRF-based interrogation systems may provide impetus for efforts in light source development for applications related to national security and industry.

  4. Bright, water-soluble CeF3 photo-, cathodo-, and X-ray luminescent nanoparticles

    International Nuclear Information System (INIS)

    Bright, water-soluble CeF3 nanoparticles with small size and narrow size distribution have been synthesized using a simple co-precipitation method without any ligands. Size control of nanoparticles from 13 ± 2 to 9 ± 2 nm was achieved by varying the reaction time. Colloidal properties have been found to vary with pH and, independently, with dilution. The photoluminescence of the as-synthesized nanoparticles shows a highly photostable UV/Visible fluorescence band due to allowed 5d–4f transitions, also observed in the X-ray luminescence spectrum. This band is suitable for X-ray excitation of a range of photosensitizers. The photoluminescence quantum yield of nanoparticles was also determined to be 31 %. Using the measured fluorescence decay time of 25 ns, the radiative lifetime of Ce in CeF3 was found to be 80.6 ns. Both photoluminescence and cathodoluminescence emission are affected by the reaction time and measurement temperature. Electron-beam-induced defect annealing is also observed

  5. Night sky brightness at San Pedro Martir Observatory

    CERN Document Server

    Plauchu-Frayn, I; Colorado, E; Herrera, J; Cordova, A; Cesena, U; Avila, F

    2016-01-01

    We present optical UBVRI zenith night sky brightness measurements collected on eighteen nights during 2013--2016 and SQM measurements obtained daily over twenty months during 2014--2016 at the Observatorio Astronomico Nacional on the Sierra San Pedro Martir (OAN-SPM) in Mexico. The UBVRI data is based upon CCD images obtained with the 0.84m and 2.12m telescopes, while the SQM data is obtained with a high-sensitivity, low-cost photometer. The typical moonless night sky brightness at zenith averaged over the whole period is U = 22.68, B = 23.10, V = 21.84, R = 21.04, I = 19.36, and SQM = 21.88 mag/square arcsec, once corrected for zodiacal light. We find no seasonal variation of the night sky brightness measured with the SQM. The typical night sky brightness values found at OAN-SPM are similar to those reported for other astronomical dark sites at a similar phase of the solar cycle. We find a trend of decreasing night sky brightness with decreasing solar activity during period of the observations. This trend im...

  6. The night sky brightness at Potsdam-Babelsberg

    CERN Document Server

    Puschnig, Johannes; Posch, Thomas; Schwarz, Robert

    2013-01-01

    We analyze the results of a 2 years (2011--2012) time series of night sky photometry performed at the Leibniz Institute for Astrophysics in Potsdam (AIP). This observatory is located on top of a hill ("Babelsberg"), 22\\,km to the southwest of the center of Berlin. The measurements have been performed with a Unihedron Sky Quality Meter. We find night sky brightness values ranging from 16.5 to 20.3 mag$_{\\rm SQM}$ arcsec$^{-2}$; the latter (best) value corresponds to 4.7 times the natural zenithal night sky brightness. We discuss the influence of clouds, of the Moon and other factors on the night sky brightness. With respect to the influence of the Moon, it turns out that Potsdam-Babelsberg, despite its proximity to Berlin, still shows a circalunar periodicity of the night sky brightness, although it is much weaker than naturally. The light-pollution-enhancing effect of clouds dominates the night sky brightness by far. Overcast nights with light pollution (up to 16.5 mag$_{\\rm SQM}$ arcsec$^{-2}$) are brighter ...

  7. PROFFIT: Analysis of X-ray surface-brightness profiles

    Science.gov (United States)

    Eckert, Dominique

    2016-08-01

    PROFFIT analyzes X-ray surface-brightness profiles for data from any X-ray instrument. It can extract surface-brightness profiles in circular or elliptical annuli, using constant or logarithmic bin size, from the image centroid, the surface-brightness peak, or any user-given center, and provides surface-brightness profiles in any circular or elliptical sectors. It offers background map support to extract background profiles, can excise areas using SAO DS9-compatible (ascl:0003.002) region files to exclude point sources, provides fitting with a number of built-in models, including the popular beta model, double beta, cusp beta, power law, and projected broken power law, uses chi-squared or C statistic, and can fit on the surface-brightness or counts data. It has a command-line interface similar to HEASOFT’s XSPEC (ascl:9910.005) package, provides interactive help with a description of all the commands, and results can be saved in FITS, ROOT or TXT format.

  8. Bright artificial light subsensitizes a central muscarinic mechanism.

    Science.gov (United States)

    Dilsaver, S C; Majchrzak, M J

    1987-12-14

    Supersensitivity of a muscarinic mechanism is implicated in the pathophysiology of depression. Bright artificial light is efficacious in the treatment of Seasonal Affective Disorder (SAD). We studied the effect of constant bright light (11,500 lux) on the sensitivity of adult, male rats to oxotremorine, 1.5 mg/kg ip, using a repeated measures design. Oxotremorine challenges were proceeded by the injection of methylscopolamine, 1 mg/kg ip, by 30 minutes. Temperature was telemetrically measured every 10 minutes for 120 minutes starting 10 minutes after the injection of oxotremorine. Prior to and after 7 continuous days of exposure to bright light, the sample exhibited a hypothermic response of 2.50 +/- 0.48 degrees C (mean +/- SEM) and 0.29 +/- 0.31 degrees C (mean +/- SEM), respectively (p less than 0.0014). All 7 animals exhibited blunting to the thermic response to oxotremorine. Bright light also blocked the capacity of amitriptyline to supersensitize a central muscarinic mechanism. Exposure to light at an intensity of 300 lux for 7 days had no effect on the thermic response to oxotremorine. These data are consistent with the hypotheses that the biology of depression involves supersensitivity of central muscarinic mechanisms and that the effects of bright artificial light are not the consequence of shifting circadian rhythms. PMID:3695799

  9. Fluorescence and Spectral Imaging

    Directory of Open Access Journals (Sweden)

    Ralph S. DaCosta

    2007-01-01

    Full Text Available Early identification of dysplasia remains a critical goal for diagnostic endoscopy since early discovery directly improves patient survival because it allows endoscopic or surgical intervention with disease localized without lymph node involvement. Clinical studies have successfully used tissue autofluorescence with conventional white light endoscopy and biopsy for detecting adenomatous colonic polyps, differentiating benign hyperplastic from adenomas with acceptable sensitivity and specificity. In Barrett's esophagus, the detection of dysplasia remains problematic because of background inflammation, whereas in the squamous esophagus, autofluorescence imaging appears to be more dependable. Point fluorescence spectroscopy, although playing a crucial role in the pioneering mechanistic development of fluorescence endoscopic imaging, does not seem to have a current function in endoscopy because of its nontargeted sampling and suboptimal sensitivity and specificity. Other point spectroscopic modalities, such as Raman spectroscopy and elastic light scattering, continue to be evaluated in clinical studies, but still suffer the significant disadvantages of being random and nonimaging. A recent addition to the fluorescence endoscopic imaging arsenal is the use of confocal fluorescence endomicroscopy, which provides real-time optical biopsy for the first time. To improve detection of dysplasia in the gastrointestinal tract, a new and exciting development has been the use of exogenous fluorescence contrast probes that specifically target a variety of disease-related cellular biomarkers using conventional fluorescent dyes and novel potent fluorescent nanocrystals (i.e., quantum dots. This is an area of great promise, but still in its infancy, and preclinical studies are currently under way.

  10. Bright and Not-So-Bright Prospects for Women in Physics in China-Beijing

    Science.gov (United States)

    Wu, Ling-An; Yang, Zhongqin; Ma, Wanyun

    2009-04-01

    Science in China-Beijing is enjoying a healthy increase in funding year by year, so the prospects for physicists are also bright. However, employment discrimination against women, formerly unthinkable, is becoming more and more explicit as the country evolves toward a market economy. Some recruitment notices bluntly state that only men will be considered, or impose restrictions upon potential female candidates. Female associate professors in many institutions are forced to retire at age 55, compared with 60 for men. This double-pinching discrimination against both younger and older women threatens to lead to a "pincer" effect, more serious than the "scissors" effect. Indeed, the ratio of senior-level women physicists in general has dropped significantly in recent years in China. Ironically, the number of female students applying for graduate studies is on the rise, as it is becoming increasingly difficult for them to compete with men in the job market with just an undergraduate degree. The Chinese Physical Society has made certain efforts to promote the image of women physicists, but it will take time and effort to reverse the trend.

  11. Influence of Type of Electric Bright Light on the Attraction of the African Giant Water Bug, Lethocerus indicus (Hemiptera: Belostomatidae

    Directory of Open Access Journals (Sweden)

    Luke Chinaru Nwosu

    2012-01-01

    Full Text Available This study investigated the influence of type of electric bright light (produced by fluorescent light tube and incandescent light bulb on the attraction of the African giant water bug, Lethocerus indicus (Hemiptera: Belostomatidae. Four fluorescent light tubes of 15 watts each, producing white-coloured light and four incandescent light bulbs of 60 watts each, producing yellow-coloured light, but both producing the same amount of light, were varied and used for the experiments. Collections of bugs at experimental house were done at night between the hours of 8.30 pm and 12 mid-night on daily basis for a period of four months per experiment in the years 2008 and 2009. Lethocerus indicus whose presence in any environment has certain implications was the predominant belostomatid bug in the area. Use of incandescent light bulbs in 2009 significantly attracted more Lethocerus indicus 103 (74.6% than use of fluorescent light tubes 35 (25.41% in 2008 [4.92=0.0001]. However, bug’s attraction to light source was not found sex dependent [>0.05; (>0.18=0.4286 and >0.28=0.3897]. Therefore, this study recommends the use of fluorescent light by households, campgrounds, and other recreational centres that are potentially exposed to the nuisance of the giant water bugs. Otherwise, incandescent light bulbs should be used when it is desired to attract the presence of these aquatic bugs either for food or scientific studies.

  12. Highly thermostable fluorescent proteins

    Science.gov (United States)

    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.

  13. Low surface brightness galaxies in the cluster A1367

    International Nuclear Information System (INIS)

    We have obtained deep CCD frames of apparently blank regions of sky in the hope of detecting very low surface brightness (LSB) objects in the cluster A1367. We discuss our data reduction, and image detection and selection techniques. If the galaxies detected are actually cluster members then they are dwarfs and the conclusions of a previous paper on the Fornax cluster are essentially confirmed. One area of variance is that the lowest surface brightness galaxies do not appear to be preferentially concentrated towards the cluster centre. This can be explained by there being a much larger density of dwarf galaxies over this bright galaxy-rich region of the universe. We find over our small area approximately four times as many LSB galaxies as would be expected from our Fornax data. We speculate on the possible origin and likely intensity of intergalactic light within clusters. (author)

  14. Low dimensional neutron moderators for enhanced source brightness

    DEFF Research Database (Denmark)

    Mezei, Ferenc; Zanini, Luca; Takibayev, Alan;

    2014-01-01

    In a recent numerical optimization study we have found that liquid para-hydrogen coupled cold neutron moderators deliver 3–5 times higher cold neutron brightness at a spallation neutron source if they take the form of a flat, quasi 2-dimensional disc, in contrast to the conventional more voluminous...... cold neutrons. This model leads to the conclusions that the optimal shape for high brightness para-hydrogen neutron moderators is the quasi 1-dimensional tube and these low dimensional moderators can also deliver much enhanced cold neutron brightness in fission reactor neutron sources, compared to the...... shapes used by now. In the present paper we describe a simple theoretical explanation of this unexpected behavior, which is based on the large difference in para-hydrogen between the values of the scattering mean free path for thermal neutrons (in the range of 1 cm) and its much larger equivalent for...

  15. Fluorescent property of indocyanine green (ICG) rubber ring using LED and laser light sources.

    Science.gov (United States)

    Hong, Nha Young; Kim, Hong Rae; Lee, Hyun Min; Sohn, Dae Kyung; Kim, Kwang Gi

    2016-05-01

    Fluorescent properties of ICG depends on solvent. Fluorescent characteristics of ICG rubber rings and optimized detection system condition were identified. The fluorescent rubber rings are produced by drying mixture of ICG solution and liquid rubber. LED and laser light sources were used to test differences between them. Other variables are ICG molar concentration (100, 80, 60, 40, 20, 10μM), excitation light spectrum (740, 760, 785nm) and angle of view (0~80°). We observed that ICG ring emitted fluorescence at longer wavelength than in blood and aqueous state. Observation angle between 0 and 50 provided similar brightness of images, while others are significantly less luminous. Excitation light between 740~760nm ensured non-overlapping spectrums of excitation light and fluorescence emission. PMID:27280060

  16. Effects of Bright Light Treatment on Psychomotor Speed in Athletes

    Directory of Open Access Journals (Sweden)

    MikkoPaavoTulppo

    2014-05-01

    Full Text Available Purpose: A recent study suggests that transcranial brain targeted light treatment via ear canals may have physiological effects on brain function studied by functional magnetic resonance imaging (fMRI techniques in humans. We tested the hypothesis that bright light treatment could improve psychomotor speed in professional ice hockey players. Methods: Psychomotor speed tests with audio and visual warning signals were administered to a Finnish National Ice Hockey League team before and after 24 days of transcranial bright light or sham treatment. The treatments were given during seasonal darkness in the Oulu region (latitude 65 degrees north when the strain on the players was also very high (10 matches during 24 days. A daily 12-min dose of bright light or sham (n = 11 for both treatment was given every morning between 8–12 am at home with a transcranial bright light device. Mean reaction time and motor time were analyzed separately for both psychomotor tests. Analysis of variance for repeated measures adjusted for age was performed. Results: Time x group interaction for motor time with a visual warning signal was p = 0.024 after adjustment for age. In Bonferroni post-hoc analysis, motor time with a visual warning signal decreased in the bright light treatment group from 127 ± 43 to 94 ± 26 ms (p = 0.024 but did not change significantly in the sham group 121 ± 23 vs. 110 ± 32 ms (p = 0.308. Reaction time with a visual signal did not change in either group. Reaction or motor time with an audio warning signal did not change in either the treatment or sham group. Conclusion: Psychomotor speed, particularly motor time with a visual warning signal, improves after transcranial bright light treatment in professional ice-hockey players during the competition season in the dark time of the year.

  17. The possible origin of facular brightness in the solar atmosphere

    Science.gov (United States)

    Kostik, R.; Khomenko, E.

    2016-05-01

    This paper studies the dependence of the Ca ii H line core brightness on the strength and inclination of the photospheric magnetic field, and on the parameters of convective and wave motions in a facular region at the center of the solar disc. We use three simultaneous data sets that were obtained at the German Vacuum Tower Telescope (Observatorio del Teide, Tenerife): (1) spectra of Ba ii 4554 Å line, registered with the instrument TESOS to measure the variations of intensity and velocity through the photosphere up to the temperature minimum; (2) spectropolarimetric data in Fe i 1.56 μm lines (registered with the instrument TIP II) to measure photospheric magnetic fields; (3) filtergrams in Ca ii H that give information about brightness fluctuations in the chromosphere. The results show that the Ca ii H brightness in the facula strongly depends on the power of waves with periods in the 5-min range, which propagate upwards, and also on the phase shift between velocity oscillations at the bottom photosphere and around the temperature minimum height that is measured from Ba ii line. The Ca ii H brightness is maximum at locations where the phase shift between temperature and velocity oscillations lies within 0°-100°. There is an indirect influence of convective motions on the Ca ii H brightness. The higher the amplitude of convective velocities is and the greater the height is where they change their direction of motion, the brighter the facula. In summary, our results lead to conclusions that facular regions appear bright not only because of the Wilson depression in magnetic structures, but also owing to real heating.

  18. Absolute brightness temperature measurements at 2.1-mm wavelength

    Science.gov (United States)

    Ulich, B. L.

    1974-01-01

    Absolute measurements of the brightness temperatures of the Sun, new Moon, Venus, Mars, Jupiter, Saturn, and Uranus, and of the flux density of DR21 at 2.1-mm wavelength are reported. Relative measurements at 3.5-mm wavelength are also preented which resolve the absolute calibration discrepancy between The University of Texas 16-ft radio telescope and the Aerospace Corporation 15-ft antenna. The use of the bright planets and DR21 as absolute calibration sources at millimeter wavelengths is discussed in the light of recent observations.

  19. High-brightness displays in integrated weapon sight systems

    Science.gov (United States)

    Edwards, Tim; Hogan, Tim

    2014-06-01

    In the past several years Kopin has demonstrated the ability to provide ultra-high brightness, low power display solutions in VGA, SVGA, SXGA and 2k x 2k display formats. This paper will review various approaches for integrating high brightness overlay displays with existing direct view rifle sights and augmenting their precision aiming and targeting capability. Examples of overlay display systems solutions will be presented and discussed. This paper will review significant capability enhancements that are possible when augmenting the real-world as seen through a rifle sight with other soldier system equipment including laser range finders, ballistic computers and sensor systems.

  20. Fluorescent filtered electrophosphorescence

    Science.gov (United States)

    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.

  1. The Physics and Applications of High Brightness Beams: Working Group A Summary on High Brightness Beam Production

    International Nuclear Information System (INIS)

    Working group A was devoted to high brightness beam production and characterization. The presentations and discussions could be categorized as cathode physics, new photoinjector designs, computational modeling of high brightness beams, and new experimental methods and results. Several novel injector and cathode designs were presented. However, a standard 1.5 cell rf photoinjector is still the most common source for high brightness beams. New experimental results and techniques were presented and thoroughly discussed. The brightest beam produced in a rf photoinjector published at the time of the workshop is approximately 2 1014 A/(m-rad)2 at Sumitomo Heavy Industries in Japan with 1 nC of charge, a 9 ps FWHM long laser pulse and a normalized transverse emittance of 1.2 pm. The emittance was achieved by utilizing a temporally flat laser pulse which decreased the emittance by an estimated factor of 2 from the beam produced with a Gaussian pulse shape with an identical pulse length

  2. Fluorescence and cofluorescence enhancement of Tb(Ⅲ) complexes with pyromellitic acid by M (M =Gd,La,Ca,and Sr ions)

    Institute of Scientific and Technical Information of China (English)

    WANG Zhengxiang; CHEN Hong; SHU Wangen; ZHAO Dongbai; ZHOU Zhongcheng

    2004-01-01

    Fluorescence and cofluorescence properties of Tb(Ⅲ) solid complexes were studied using pyromellitic acid (PMA) as ligand and fluorescence inert ions as doping elements. The cofluorescence enhancement, a result of ligand sensitized fluorescence, was observed in Tb(Ⅲ) solid complexes doped with fluorescent inert ions La(Ⅲ), Gd(Ⅲ), Ca(Ⅲ), and Sr(Ⅲ). The effect of the type and content of doping elements on fluorescence enhancement was studied, and optimum conditions were determined. The results show that Gd (La, Ca, Sr) has clear cofluorescence effect in solid complex Tb-M-PMA system, and in present work, rare earth complex fluorescent powder that emits bright green fluorescence at ultraviolet excitation was obtained, which had potential application as fluorescent anti-counterfeit ink.

  3. Color-stable, reduced efficiency roll-off hybrid white organic light emitting diodes with ultra high brightness

    International Nuclear Information System (INIS)

    High-brightness and color-stable two-wavelength hybrid white organic light emitting diodes (HWOLEDs) with the configuration of indium tin oxide (ITO)/ N, N, N', N'-tetrakis(4-methoxyphenyl)-benzidine (MeO-TPD): tetrafluoro-tetracyanoqino dimethane (F4-TCNQ)/N,N'-di(naphthalene-1-yl)-N,N'-diphenyl-benzidine (NPB)/4,4-N,N-dicarbazolebiphenyl (CBP): iridium (III) diazine complexes (MPPZ)2Ir(acac)/NPB/2-methyl-9,10-di(2-naphthyl)anthracene (MADN): p-bis(p-N,N-di-phenyl-aminostyryl)benzene (DSA-ph)/ bis(10-hydroxybenzo[h] quinolinato)beryllium complex (Bebq2)/LiF/Al have been fabricated and characterized. The optimal brightness of the device is 69932 cd/m2 at a voltage of 13 V, and the Commission Internationale de l'Eclairage (CIE) chromaticity coordinates are almost constant during a large voltage change of 6–12 V. Furthermore, a current efficiency of 15.3 cd/A at an illumination-relevant brightness of 1000 cd/m2 is obtained, which rolls off slightly to 13.0 cd/A at an ultra high brightness of 50000 cd/m2 . We attribute this great performance to wisely selecting an appropriate spacer together with effectively utilizing the combinations of exciton-harvested orange-phosphorescence/ blue-fluorescence in the device. Undoubtedly, this is one of the most exciting results in two-wavelength HWOLEDs up to now

  4. A novel study on the mechanisms of drug release in PLGA-mPEG microspheres with fluorescent drug.

    Science.gov (United States)

    Shi, Chen; Feng, Shuibin; Liu, Ping; Liu, Xianzhe; Feng, Xiaobo; Fu, Dehao

    2016-06-01

    The purpose of this research was to proof the microspheres release mechanism by a novel method-detecting and comparing the drugs fluorescent changes on the microspheres surface. Fluorescein sodium (FS, 0.4 kDa) and fluorescein isothiocyanate-bovine serum albumin (FITC-BSA, 66.8 kDa) were employed as model drugs. FS and FITC-BSA were encapsulated into PLGA-mPEG microspheres through double emulsion evaporation method, and the drug-loaded microspheres in vitro degradation and release behaviors were evaluated by scanning electron microscope, gel permeation chromatography, confocal laser scanning microscopy (CLSM), BCA assay kit, and UV-vis spectrophotometry. FS-loaded microspheres revealed a severe initial burst release, followed by a sustained release, and we could observe a bright fluorescent on the microspheres surface during the early release period under the CLSM. The bright fluorescent gradually faded out in the later period as only 1~2% FS was remained after 14 days release. FITC-BSA-loaded microspheres revealed a typical tri-phase release profile, and we observed a weak fluorescent on the microspheres surface after the initial burst release, and the fluorescent came bright again after an obvious erosion appeared on the microspheres surface. In the later release stage, the fluorescent gradually faded out as the fast release of FITC-BSA. PMID:26980344

  5. Tumor-stem cells interactions by fluorescence imaging

    Science.gov (United States)

    Meleshina, Aleksandra V.; Cherkasova, Elena I.; Sergeeva, Ekaterina; Turchin, Ilya V.; Kiseleva, Ekaterina V.; Dashinimaev, Erdem B.; Shirmanova, Marina V.; Zagaynova, Elena V.

    2013-02-01

    Recently, great deal of interest is investigation the function of the stem cells (SC) in tumors. In this study, we studied «recipient-tumor- fluorescent stem cells » system using the methods of in vivo imaging and laser scanning microscopy (LSM). We used adipose-derived adult stem (ADAS) cells of human lentiviral transfected with the gene of fluorescent protein Turbo FP635. ADAS cells were administrated into nude mice with transplanted tumor HeLa Kyoto (human cervical carcinoma) at different stages of tumor growth (0-8 days) intravenously or into tumor. In vivo imaging was performed on the experimental setup for epi - luminescence bioimaging (IAP RAS, Nizhny Novgorod). The results of the imaging showed localization of fluorophore tagged stem cells in the spleen on day 5-9 after injection. The sensitivity of the technique may be improved by spectral separation autofluorescence and fluorescence of stem cells. We compared the results of in vivo imaging and confocal laser scanning microscopy (LSM 510 META, Carl Zeiss, Germany). Internal organs of the animals and tumor tissue were investigated. It was shown that with i.v. injection of ADAS, bright fluorescent structures with spectral characteristics corresponding to TurboFP635 protein are locally accumulated in the marrow, lungs and tumors of animals. These findings indicate that ADAS cells integrate in the animal body with transplanted tumor and can be identified by fluorescence bioimaging techniques in vivo and ex vivo.

  6. Chlorophyll fluorescence analysis and imaging in plant stress and disease

    Energy Technology Data Exchange (ETDEWEB)

    Daley, P.F.

    1994-12-01

    Quantitative analysis of chlorophyll fluorescence transients and quenching has evolved rapidly in the last decade. Instrumentation capable of fluorescence detection in bright actinic light has been used in conjunction with gas exchange analysis to build an empirical foundation relating quenching parameters to photosynthetic electron transport, the state of the photoapparatus, and carbon fixation. We have developed several instruments that collect video images of chlorophyll fluorescence. Digitized versions of these images can be manipulated as numerical data arrays, supporting generation of quenching maps that represent the spatial distribution of photosynthetic activity in leaves. We have applied this technology to analysis of fluorescence quenching during application of stress hormones, herbicides, physical stresses including drought and sudden changes in humidity of the atmosphere surrounding leaves, and during stomatal oscillations in high CO{sub 2}. We describe a recently completed portable fluorescence imaging system utilizing LED illumination and a consumer-grade camcorder, that will be used in long-term, non-destructive field studies of plant virus infections.

  7. Unusual behavior of Tb3+ in K3YF6 green-emitting phosphor.

    Science.gov (United States)

    Gusowski, Marek A; Ryba-Romanowski, Witold

    2008-08-15

    We report on photoluminescence studies of Tb3+ in a polycrystalline cryolite type K3YF6 host. The location of the Tb3+ in the center of inversion forbids the electric-dipole transitions of terbium ions in this material. As a consequence almost the entire luminescence intensity is related to the 5D4-(7)F5 magnetic-dipole transition, and it is contained in the extremely narrow spectral bandwidth amounting to 1.7 nm at 8K and to 18 nm at room temperature. The phosphor under study can be efficiently excited making use of intense f-d transitions of Tb3+ in the UV-vacuum-UV region and may be of interest for applications requiring high spectral purity of the emission. PMID:18709087

  8. [Cathodoluminescent characteristics of green-emitting ZnAl2O4:Mn thin film phosphors].

    Science.gov (United States)

    Lou, Zhi-dong; Xu, Zheng; Yi, Lan-jie; Yang, Sheng-yi

    2008-06-01

    Green electroluminescence was obtained from thin films of ZnAl2O4: Mn prepared by rf magnetron sputtering onto thick insulating ceramic sheets. Photoluminescence and stress-stimulated luminescence was obtained for Mn-doped ZnAl2O4 powder synthesized by the solid phase reaction. Since it is extremely stable chemically and thermally, ZnAl2O4 may emerge as an alternative choice to sulphide-based phosphors. In the present paper, thin films of ZnAl2O4: Mn were grown on aluminosilicate ceramic plates using spray pyrolysis of aqueous solutions. The cathodoluminescence (CL) properties of the films under low to medium excitation voltage (spinel structure. The chromaticity coordinates were x = 0.150 and y = 0.734 with a dominant wavelength of 525 nm and an 82% color purity. The CL luminance and efficiency depended on the excitation voltage and current density. Saturation effects were observed as the current density increased. A luminance of 540 cd x m(-2) and an efficiency of 4.5 lm x W(-1) were obtained at an excitation voltage of 4 kV with a current density of 38 microA x cm(-2). PMID:18800691

  9. Blue and green emitting Ce3+ and Tb3+ codoped Gd2O3 nanophosphors

    International Nuclear Information System (INIS)

    Tb3+ doped Gd2O3 nanoparticles of 4-10 nm in size were synthesized from nitrate precursors by urea hydrolysis method in ethylene glycol medium at low temperature of 140 ℃. Characteristic Tb3+ ion green emission corresponding to 5D4 ’! 7FJ was observed to be very strong, which further increases with heat treatment temperature. Characteristic blue color emission of Ce3+ ion transitions for 5d’! 2F7/2 and 2F5/2 (at 422 nm and 485 nm respectively) was found to be very strong in as-synthesized Ce0.06Tb0.14Gd0.8O3 nanoparticles. However, its luminescence intensity decreases with increase in heating temperature or increase in the particle size/crystallinity, whereas there was a weak emission peak of Tb3+ ion at 545 nm. The polycrystalline nature of as-prepared sample change to highly crystalline state when heated at elevated temperature (900 ℃). (author)

  10. Tb3+ doped Zinc Alumino Bismuth Borate glasses for green emitting luminescent devices

    International Nuclear Information System (INIS)

    Zinc Alumino Bismuth Borate (ZnAlBiB) glasses doped with terbium (Tb3+) ions with a chemical composition 20ZnO–10Al2O3–(10−x)Bi2O3–60B2O3−xTb2O3 (x=0.1, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 mol%) were prepared by a conventional melt quenching method and studied their optical absorption, photoluminescence and decay spectral properties. The Judd–Ofelt (J–O) parameters evaluated from the experimental oscillator strengths were used to measure the radiative properties for the prominent luminescent transitions of Tb3+ ions such as 5D4→7F6, 7F5, 7F4 and 7F3. The effect of Tb3+ ion concentration on the luminescence process observed in the visible region was discussed in detail. The emission spectra recorded for all the ZnAlBiB glasses doped with Tb3+ ions, show an intense peak in green region at 542 nm. The stimulated emission cross-section, branching ratios and quantum efficiency values evaluated for green emission (5D4→7F5) suggests the utility of these glasses for green luminescence applications. It was found that, within the concentration range investigated, 2.5 mol% of Tb3+ doped ZnAlBiB glass is most suitable for green luminescence applications at 542 nm in principle. - Highlights: • ZnAlBiB glasses doped with Tb3+ ions were prepared by a conventional melt quenching technique. • Judd–Ofelt and radiative properties are measured from the emission spectra. • Quantum efficiency of the ZnAlBiB glasses is measured by using radiative and measured lifetimes. • CIE Chromaticity co-ordinates are evaluated from emission spectra

  11. Tb{sup 3+} doped Zinc Alumino Bismuth Borate glasses for green emitting luminescent devices

    Energy Technology Data Exchange (ETDEWEB)

    Swapna, K.; Mahamuda, Sk. [Department of Physics, K L University, Green Fields, Vaddeswaram, Guntur (Dt), Andhra Pradesh 522502 (India); Rao, A. Srinivasa, E-mail: drsrallam@gmail.com [Department of Physics, K L University, Green Fields, Vaddeswaram, Guntur (Dt), Andhra Pradesh 522502 (India); Department of Applied Physics, Delhi Technological University, Bawana Road, New Delhi 110042 (India); Jayasimhadri, M. [Department of Applied Physics, Delhi Technological University, Bawana Road, New Delhi 110042 (India); Shakya, Suman; Prakash, G. Vijaya [Nanophotonics Laboratory, Department of Physics, Indian Institute of Technology-Delhi, Hauz Khas, New Delhi 110016 (India)

    2014-12-15

    Zinc Alumino Bismuth Borate (ZnAlBiB) glasses doped with terbium (Tb{sup 3+}) ions with a chemical composition 20ZnO–10Al{sub 2}O{sub 3}–(10−x)Bi{sub 2}O{sub 3}–60B{sub 2}O{sub 3}−xTb{sub 2}O{sub 3} (x=0.1, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 mol%) were prepared by a conventional melt quenching method and studied their optical absorption, photoluminescence and decay spectral properties. The Judd–Ofelt (J–O) parameters evaluated from the experimental oscillator strengths were used to measure the radiative properties for the prominent luminescent transitions of Tb{sup 3+} ions such as {sup 5}D{sub 4}→{sup 7}F{sub 6}, {sup 7}F{sub 5}, {sup 7}F{sub 4} and {sup 7}F{sub 3.} The effect of Tb{sup 3+} ion concentration on the luminescence process observed in the visible region was discussed in detail. The emission spectra recorded for all the ZnAlBiB glasses doped with Tb{sup 3+} ions, show an intense peak in green region at 542 nm. The stimulated emission cross-section, branching ratios and quantum efficiency values evaluated for green emission ({sup 5}D{sub 4}→{sup 7}F{sub 5}) suggests the utility of these glasses for green luminescence applications. It was found that, within the concentration range investigated, 2.5 mol% of Tb{sup 3+} doped ZnAlBiB glass is most suitable for green luminescence applications at 542 nm in principle. - Highlights: • ZnAlBiB glasses doped with Tb{sup 3+} ions were prepared by a conventional melt quenching technique. • Judd–Ofelt and radiative properties are measured from the emission spectra. • Quantum efficiency of the ZnAlBiB glasses is measured by using radiative and measured lifetimes. • CIE Chromaticity co-ordinates are evaluated from emission spectra.

  12. Synthesis of polymeric fluorescent brightener based on coumarin and its performances on paper as light stabilizer, fluorescent brightener and surface sizing agent

    Science.gov (United States)

    Zhang, Guanghua; Zheng, Hua; Guo, Mingyuan; Du, Lun; Liu, Guojun; Wang, Peng

    2016-03-01

    In this work, a novel polymeric fluorescent brightener based on coumarin (PFBC) was synthesized, using three-step synthetic route, from 7-amino-4-methylcoumarin, coumarin monomer (FBC), Acrylamide (AM) and methacrylatoethyl trimethyl ammonium chloride (DMC). The structure of PFBC was characterized by FT-IR, 1HNMR and GPC. PFBC was applied to paper fiber as light stabilizer, fluorescent brightener and surface sizing agent and its performances were evaluated by measuring the UV-vis, fluorescence, thermal stability, the cationic degree, surface strength and smoothness of paper, the brightness degree of paper and the PC value of paper. Results showed that PFBC had better solubility in water than that of FBC, by measuring the optical properties. Through the surface sizing experiment and UV aging experiment, PFBC not only enhanced the surface strength and smoothness of paper as a surface sizing agent, but also had better effect on anti-UV aging than that of FBC as light stabilizer and fluorescent brightener.

  13. Compact collimators for high brightness blue LEDs using dielectric multilayers

    NARCIS (Netherlands)

    Cornelissen, H.J.; Ma, H.; Ho, C.; Li, M.; Mu, C.

    2011-01-01

    A novel method is presented to inject the light of millimeter-sized high-brightness blue LEDs into light guides of submillimeter thickness. Use is made of an interference filter that is designed to pass only those modes that will propagate in the light guide by total internal reflection. Other modes

  14. Soil Moisture Active/Passive (SMAP) Forward Brightness Temperature Simulator

    Science.gov (United States)

    Peng, Jinzheng; Peipmeier, Jeffrey; Kim, Edward

    2012-01-01

    The SMAP is one of four first-tier missions recommended by the US National Research Council's Committee on Earth Science and Applications from Space (Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond, Space Studies Board, National Academies Press, 2007) [1]. It is to measure the global soil moisture and freeze/thaw from space. One of the spaceborne instruments is an L-band radiometer with a shared single feedhorn and parabolic mesh reflector. While the radiometer measures the emission over a footprint of interest, unwanted emissions are also received by the antenna through the antenna sidelobes from the cosmic background and other error sources such as the Sun, the Moon and the galaxy. Their effects need to be considered accurately, and the analysis of the overall performance of the radiometer requires end-to-end performance simulation from Earth emission to antenna brightness temperature, such as the global simulation of L-band brightness temperature simulation over land and sea [2]. To assist with the SMAP radiometer level 1B algorithm development, the SMAP forward brightness temperature simulator is developed by adapting the Aquarius simulator [2] with necessary modifications. This poster presents the current status of the SMAP forward brightness simulator s development including incorporating the land microwave emission model and its input datasets, and a simplified atmospheric radiative transfer model. The latest simulation results are also presented to demonstrate the ability of supporting the SMAP L1B algorithm development.

  15. Matter wave interference pattern in the collision of bright solitons

    International Nuclear Information System (INIS)

    We investigate the dynamics of Bose-Einstein condensates in a quasi one-dimensional regime in a time-dependent trap and show analytically that it is possible to observe matter wave interference patterns in the intra-trap collision of two bright solitons by selectively tuning the trap frequency and scattering length.

  16. Minimum-phase distribution of cosmic source brightness

    International Nuclear Information System (INIS)

    Minimum-phase distributions of brightness (profiles) for cosmic radio sources 3C 144 (the wave lambda=21 cm), 3C 338 (lambda=3.5 m), and 3C 353 (labda=31.3 cm and 3.5 m) are obtained. A real possibility for the profile recovery from module fragments of its Fourier-image is shown

  17. The HI dominated Low Surface Brightness Galaxy KKR17

    CERN Document Server

    Lam, Man I; Yang, Ming; Zhou, Zhi-Min; Du, Wei; Zhu, Yi-Nan

    2014-01-01

    We present new narrow-band (H$\\alpha$ and [OIII]) imagings and optical spectrophotometry of HII regions for a gas-rich low surface brightness irregular galaxy, KKR 17. The central surface brightness of the galaxy is $\\mu_0(B)$ = 24.15 $\\pm$0.03 mag~sec$^{-2}$. The galaxy was detected by \\emph{Arecibo Legacy Fast ALFA survey} (ALFALFA), and its mass is dominated by neutral hydrogen (HI) gas. In contrast, both the stellar masses of the bright HII and diffuse stellar regions are small. In addition, the fit to the spectral energy distribution to each region shows the stellar populations of HII and diffuse regions are different. The bright HII region contains a large fraction of O-type stars, revealing the recent strong star formation, whereas the diffuse region is dominated by median age stars, which has a typical age of $\\sim$ 600 Myrs. Using the McGaugh's abundance model, we found that the average metallicity of KKR 17 is 12 + (O/H) = 8.0 $\\pm$ 0.1. The star formation rate of KKR 17 is 0.21$\\pm$0.04 M$_{\\odot}$...

  18. Bright infrared LEDs based on colloidal quantum-dots

    KAUST Repository

    Sun, Liangfeng

    2013-01-01

    Record-brightness infrared LEDs based on colloidal quantum-dots have been achieved through control of the spacing between adjacent quantum-dots. By tuning the size of quantum-dots, the emission wavelengths can be tuned between 900nm and 1650nm. © 2013 Materials Research Society.

  19. Bright-dark incoherently coupled photovoltaic soliton pair

    Institute of Scientific and Technical Information of China (English)

    Hou Chun-Feng; Pei Yan-Bo; Zhou Zhong-Xiang; Sun Xiu-Dong

    2005-01-01

    The coupling between two mutually incoherent optical beams that propagate collinearly in open-circuit photovoltaic photorefractive media is investigated. It is shown that an incoherently coupled bright-dark spatial soliton pair can be formed due to photovoltaic effect. The physical properties of such a soliton pair are also discussed.

  20. The star-bright hour : [poems] / Betti Alver

    Index Scriptorium Estoniae

    Alver, Betti, 1906-1989

    2003-01-01

    Autori lühitutvustus lk. 231. Sisu: The star-bright hour ; The debt ; Not a dream ; Fog-bound ; Corals in an Ancient river ; Frou-frou 1-3. Orig.: Tähetund ; Vilepuhuja ; Võlg ; "Mitte viirastus, meelepett..." ; Udus ; Korallid Emajões ; Froufrou 1-3

  1. Bright soliton trains of trapped Bose-Einstein condensates

    OpenAIRE

    Al Khawaja, U.; Stoof, H. T. C.; Hulet, R. G.; Strecker, K.E.; Patridge, G.B.

    2002-01-01

    We variationally determine the dynamics of bright soliton trains composed of harmonically trapped Bose-Einstein condensates with attractive interatomic interactions. In particular, we obtain the interaction potential between two solitons. We also discuss the formation of soliton trains due to the quantum mechanical phase fluctuations of a one-dimensional condensate.

  2. Bright X-ray galaxies in SDSS filaments

    OpenAIRE

    Tugay, A. V.

    2013-01-01

    Eighteen bright X-ray emitting galaxies were found in nearby filaments within SDSS region. Basic X-ray spectral parameters were estimated for these galaxies using power law model with photoelectric absorption. A close pair of X-ray galaxies was found.

  3. Optical variability of the medium-bright quasar sample

    International Nuclear Information System (INIS)

    A variability study of the 32-member Medium-Bright Quasar Sample is reported. It is found that the star US 1953 has undergone a noticeable variation in the course of 26 hr. Apparent variations in the extragalactic object US 3498 may be illusory, owing to its partially resolved appearance. No other evidence for variability was detected. 34 refs

  4. Thermionic sources for HI-brightness electron beams

    International Nuclear Information System (INIS)

    This paper surveys the capabilities and limitations of modern thermionic electron sources for producing high emission density (>10 A/cm2)-high brightness beams. The emphasis is on dispenser cathodes. The capabilities of existing commercial cathodes as well as the potential for future cathode improvements as demonstrated in various prototype structures are described

  5. Enhancing the brightness of high current electron guns

    International Nuclear Information System (INIS)

    Concepts such as the two-beam accelerator offer the possibility of translating pulsed power technology into a form useful to the design of high luminosity accelerators for high-energy physics applications. Realization of the promise of these concepts will require the design of electron guns which are optimized with respect to beam brightness at current levels of approximately 1 kA. Because high luminosity implies accelerator operation at high repetition rates, the high-current beam source must be designed so that the beam does not intercept the electrodes. In our investigations of electron gun configurations, we have found that the brightness of a given source is set by practical design choices such as peak voltage, cathode type, gun electrode geometry, and focusing field topology. To investigate the sensitivity of beam brightness to these factors in a manner suitable for modelling transient phenomena at the beam head, we have developed a Darwin approximation particle code, DPC. The main component in our experimental program is a readily modified electron gun that allows us to test many candidate cathode materials, types, and electrode geometries at field stresses up to 1 MW/cm. We have also developed several diagnostics suitable for measuring the brightness of intense, low-emittance beams

  6. The star-bright hour : [luuletused] / Betti Alver

    Index Scriptorium Estoniae

    Alver, Betti, 1906-1989

    2006-01-01

    Sisu: The star-bright hour ; Not a dream ; The Piper ; Corals in an ancent river. Luuletused pärinevad kogumikust "Tuulelaeval valgusest on aerud = Windship with Oars of Light. (Tallinn : Huma, 2001). Orig.: Tähetund ; Mitte viirastus, meelepett ; Vilepuhuja ; Korallid Emajões

  7. The "Brightness Rules" Alternative Conception for Light Bulb Circuits

    Science.gov (United States)

    Bryan, Joel A.; Stuessy, Carol

    2006-01-01

    An alternative conception for the observed differences in light bulb brightness was revealed during an unguided inquiry investigation in which prospective elementary teachers placed identical bulbs in series, parallel, and combination direct current circuits. Classroom observations, document analyses, and video and audio transcriptions led to the…

  8. Variations in the Fe mineralogy of bright Martian soil

    Science.gov (United States)

    Murchie, Scott; Mustard, John; Erard, Stephane; Geissler, Paul; Singer, Robert

    1993-01-01

    Bright regions on Mars are interpreted as 'soil' derived by chemical alteration of crustal rocks, whose main pigmentary component is ferric oxide or oxyhydroxide. The mineralogy and mineralogic variability of ferric iron are important evidence for the evolution of Martian soil: mineralogy of ferric phases is sensitive to chemical conditions in their genetic environments, and the spatial distributions of different ferric phases would record a history of both chemical environments and physical mixing. Reflectance spectroscopic studies provide several types of evidence that discriminate possible pigmentary phases, including the position of a crystal field absorption near 0.9 microns and position and strengths of absorptions in the UV-visible wavelength region. Recent telescopic spectra and laboratory measurements of Mars soil analogs suggest that spectral features of bright soil can be explained based on a single pigmentary phase, hematite (alpha-Fe2O3), occurring in both 'nanophase' and more crystalline forms. Here we report on a systematic investigation of Martian bright regions using ISM imaging spectrometer data, in which we examined spatial variations in the position and shape of the approximately 0.9 microns absorption. We found both local and regional heterogeneities that indicate differences in Fe mineralogy. These results demonstrate that bright soils do not represent a single lithology that has been homogenized by eolian mixing, and suggest that weathering of soils in different geologic settings has followed different physical and chemical pathways.

  9. Fluorescent Staining of Tea Pathogenic Fungi in Tea Leaves Using Fluorescein-labeled Lectin

    Science.gov (United States)

    Yamada, Kengo; Yoshida, Katsuyuki; Sonoda, Ryoichi

    Fluorochrome-labeled lectin, fluorescein conjugated wheat germ agglutinin (F-WGA) was applied to stain tea pathogenic fungi in tea leaf tissue. Infected leaves were fixed and decolorized with a mixture of ethanol and acetic acid, and cleared with 10% KOH for whole mount before staining with F-WGA. Hyphae of Pestalotiopsis longiseta, Pseudocercospora ocellata, Botrytis cinerea and Colletotrichum theae-sinensis fluoresced brightly in whole mount and sectioned samples of infected leaf tissue. In browned tissue, hyphae did not fluoresce frequently in whole mount sample. Autofluorescence of leaf tissue was strong in browned tissue of sections, it was removed by 10% KOH treatment before staining. Penetration hyphae of C. theae-sinensis in cell wall of trichome and hyphae in basal part of trichome did not fluoresced frequently. In whole mount samples of tea leaf infected with Exobasidium vexans and E. reticulatum, hymenia appeared on leaf surface fluoresced, but hyphae in leaf tissue did not fluoresce. In sectioned samples, hyphae fluoresced brightly when sections were treated with 10% KOH before staining.

  10. Spectral Diversity and Regulation of Coral Fluorescence in a Mesophotic Reef Habitat in the Red Sea.

    Directory of Open Access Journals (Sweden)

    Gal Eyal

    Full Text Available The phenomenon of coral fluorescence in mesophotic reefs, although well described for shallow waters, remains largely unstudied. We found that representatives of many scleractinian species are brightly fluorescent at depths of 50-60 m at the Interuniversity Institute for Marine Sciences (IUI reef in Eilat, Israel. Some of these fluorescent species have distribution maxima at mesophotic depths (40-100 m. Several individuals from these depths displayed yellow or orange-red fluorescence, the latter being essentially absent in corals from the shallowest parts of this reef. We demonstrate experimentally that in some cases the production of fluorescent pigments is independent of the exposure to light; while in others, the fluorescence signature is altered or lost when the animals are kept in darkness. Furthermore, we show that green-to-red photoconversion of fluorescent pigments mediated by short-wavelength light can occur also at depths where ultraviolet wavelengths are absent from the underwater light field. Intraspecific colour polymorphisms regarding the colour of the tissue fluorescence, common among shallow water corals, were also observed for mesophotic species. Our results suggest that fluorescent pigments in mesophotic reefs fulfil a distinct biological function and offer promising application potential for coral-reef monitoring and biomedical imaging.

  11. Fluorescent Polymer Nanoparticles Based on Dyes: Seeking Brighter Tools for Bioimaging.

    Science.gov (United States)

    Reisch, Andreas; Klymchenko, Andrey S

    2016-04-01

    Speed, resolution and sensitivity of today's fluorescence bioimaging can be drastically improved by fluorescent nanoparticles (NPs) that are many-fold brighter than organic dyes and fluorescent proteins. While the field is currently dominated by inorganic NPs, notably quantum dots (QDs), fluorescent polymer NPs encapsulating large quantities of dyes (dye-loaded NPs) have emerged recently as an attractive alternative. These new nanomaterials, inspired from the fields of polymeric drug delivery vehicles and advanced fluorophores, can combine superior brightness with biodegradability and low toxicity. Here, we describe the strategies for synthesis of dye-loaded polymer NPs by emulsion polymerization and assembly of pre-formed polymers. Superior brightness requires strong dye loading without aggregation-caused quenching (ACQ). Only recently several strategies of dye design were proposed to overcome ACQ in polymer NPs: aggregation induced emission (AIE), dye modification with bulky side groups and use of bulky hydrophobic counterions. The resulting NPs now surpass the brightness of QDs by ≈10-fold for a comparable size, and have started reaching the level of the brightest conjugated polymer NPs. Other properties, notably photostability, color, blinking, as well as particle size and surface chemistry are also systematically analyzed. Finally, major and emerging applications of dye-loaded NPs for in vitro and in vivo imaging are reviewed. PMID:26901678

  12. Portable, battery-operated, fluorescence field microscope for the developing world

    Science.gov (United States)

    Miller, Andrew R.; Davis, Gregory; Pierce, Mark; Oden, Z. Maria; Richards-Kortum, Rebecca

    2010-02-01

    In many areas of the world, current methods for diagnosis of infectious diseases such as malaria and tuberculosis involve microscopic evaluation of a patient specimen. Advances in fluorescence microscopy can improve diagnostic sensitivity and reduce time and expertise necessary to interpret diagnostic results. However, modern research-grade microscopes are neither available nor appropriate for use in many settings in the developing world. To address this need, we designed, fabricated, and tested a portable, battery-powered, bright field and fluorescence inverted field microscope, optimized for infrastructural constraints of the developing world. We characterized an initial prototype constructed with rapidprototyping techniques, which utilized low-cost, over-the-counter components such as a battery-powered LED flashlight as the light source. The microscope exhibited suitable spatial resolution (0.8 μm) in fluorescence mode to resolve M. tuberculosis bacilli. In bright field mode, malaria parasites were resolvable at 1000x magnification. The initial prototype cost 480 USD and we estimate that the microscope can be manufactured for 230 USD. While future studies are planned to evaluate ease-of-use and reliability, our current system serves as a proof of concept that combined fluorescence and bright field microscopy is possible in a low-cost and portable system.

  13. Mapping the fluorescence performance of a photochromic-fluorescent system coupled with gold nanoparticles at the single-molecule-single-particle level.

    Science.gov (United States)

    Simoncelli, Sabrina; Roberti, M Julia; Araoz, Beatriz; Bossi, Mariano L; Aramendía, Pedro F

    2014-05-14

    Single-molecule (SM) fluorescence microscopy was used to investigate the photochromic fluorescent system spiropyran-merocyanine (SP ↔ MC) interacting with gold nanoparticles (AuNPs). We observe a significant increase in the brightness of the emissive MC form, in the duration of its ON time, and in the total number of emitted photons. The spatial distribution of SMs with improved photophysical performance was obtained with 40 nm precision relative to the nearest AuNP. We demonstrate that even photochromic systems with poor photochemical performance for SM can become suitable for long time monitoring and high performance microscopy by interaction with metallic NP. PMID:24766343

  14. On the model of type 1 supernova near brightness maximum

    International Nuclear Information System (INIS)

    Some photometric and spectrophotometric data about supernovae of 1 type CH-1 are analyzed. Colour /Tsub(c)/ and spectrophotmetric /T/ temperatures of SN1972-e compared. It has been concluded that at the maximum brightness tsub(m) and before the maximum Tsub(c) approximately TTsub(c) < T after the maximum brightness. A considerable deviation of Tsub(c) from T is connected with the significant role of metal lines in the attenuation of the short-wavelength region spectrum CH-1, which becomes essential when T < 10000 deg K. Behaviour of the radius of the photosphere Rp at CH-1 is investigated on the basis of the accepted dependence of T on time. It is shown that at the maximum brightness Rp, increases linearly at the rate of about 5000 km/sec, and reaches its highest value approximately in 30-35sup(d) after the maximum brightness tsub(m) and then rather quickly decreases. The rate of the expansion of the photosphere is twice lower than the mean expansion velocity of the shell CH-1. The initial moments of separation of these CH are -25sup(d) and -16sup(d) respectively (with respect to the maximum V) have been found using an extrapolation of the Rp(t) dependence for SN 1972-e and SN 1970-j. The role of the temperature dependence of non-transparency on the behavior of the photosphere Ch-1 is discussed. Bolomeic luminosity of CH-1 at the maximum brightness is investigated. Arguments supporting the conclusion that the bolometric maximum of CH-1 comes formerly to a visual one, are given

  15. A fluorescent laser-diffuser arrangement for uniform backlighting

    Science.gov (United States)

    Jain, Saransh; Somasundaram, S.; Anand, T. N. C.

    2016-02-01

    Laser-light diffusers are used in conjunction with pulsed lasers to generate bright, spatially uniform background illumination for imaging and particle sizing applications. The present paper describes a cost effective way of fabricating a fluorescent laser-light diffuser. The procedure to obtain a uniform background using laser illumination is explained. To characterize the diffuser, images are acquired using a CCD camera with the illumination provided using the diffuser and the variations of pixel intensity values along the centerline of the images are plotted. It is observed that the standard deviation of pixel intensity values is fairly small. Hence, these diffusers are suitable for experiments that need a uniform background.

  16. Fluorescent image tracking velocimeter

    Science.gov (United States)

    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.

  17. Self-assembly of diphenylalanine peptides into microtubes with "turn on" fluorescence using an aggregation-induced emission molecule.

    Science.gov (United States)

    Na, Na; Mu, Xiaoyan; Liu, Qiuling; Wen, Jiying; Wang, Fangfang; Ouyang, Jin

    2013-10-01

    The self-assembly of diphenylalanine peptides (l-Phe-l-Phe) into microtubes with "turn on" bright yellow green fluorescence was described, which was achieved using an aggregation-induced emission (AIE) molecule of 9,10-bis[4-(3-sulfonatopropoxyl)-styryl] anthracene (BSPSA) sodium. PMID:24045462

  18. LARGER PLANET RADII INFERRED FROM STELLAR ''FLICKER'' BRIGHTNESS VARIATIONS OF BRIGHT PLANET-HOST STARS

    International Nuclear Information System (INIS)

    Most extrasolar planets have been detected by their influence on their parent star, typically either gravitationally (the Doppler method) or by the small dip in brightness as the planet blocks a portion of the star (the transit method). Therefore, the accuracy with which we know the masses and radii of extrasolar planets depends directly on how well we know those of the stars, the latter usually determined from the measured stellar surface gravity, log g. Recent work has demonstrated that the short-timescale brightness variations (flicker) of stars can be used to measure log g to a high accuracy of ∼0.1-0.2 dex. Here, we use flicker measurements of 289 bright (Kepmag < 13) candidate planet-hosting stars with T eff = 4500-6650 K to re-assess the stellar parameters and determine the resulting impact on derived planet properties. This re-assessment reveals that for the brightest planet-host stars, Malmquist bias contaminates the stellar sample with evolved stars: nearly 50% of the bright planet-host stars are subgiants. As a result, the stellar radii, and hence the radii of the planets orbiting these stars, are on average 20%-30% larger than previous measurements had suggested

  19. LARGER PLANET RADII INFERRED FROM STELLAR ''FLICKER'' BRIGHTNESS VARIATIONS OF BRIGHT PLANET-HOST STARS

    Energy Technology Data Exchange (ETDEWEB)

    Bastien, Fabienne A.; Stassun, Keivan G.; Pepper, Joshua [Physics and Astronomy Department, Vanderbilt University, 1807 Station B, Nashville, TN 37235 (United States)

    2014-06-10

    Most extrasolar planets have been detected by their influence on their parent star, typically either gravitationally (the Doppler method) or by the small dip in brightness as the planet blocks a portion of the star (the transit method). Therefore, the accuracy with which we know the masses and radii of extrasolar planets depends directly on how well we know those of the stars, the latter usually determined from the measured stellar surface gravity, log g. Recent work has demonstrated that the short-timescale brightness variations ({sup f}licker{sup )} of stars can be used to measure log g to a high accuracy of ∼0.1-0.2 dex. Here, we use flicker measurements of 289 bright (Kepmag < 13) candidate planet-hosting stars with T {sub eff} = 4500-6650 K to re-assess the stellar parameters and determine the resulting impact on derived planet properties. This re-assessment reveals that for the brightest planet-host stars, Malmquist bias contaminates the stellar sample with evolved stars: nearly 50% of the bright planet-host stars are subgiants. As a result, the stellar radii, and hence the radii of the planets orbiting these stars, are on average 20%-30% larger than previous measurements had suggested.

  20. Fluorescence labeled microbubbles for multimodal imaging.

    Science.gov (United States)

    Barrefelt, Åsa; Zhao, Ying; Larsson, Malin K; Egri, Gabriella; Kuiper, Raoul V; Hamm, Jörg; Saghafian, Maryam; Caidahl, Kenneth; Brismar, Torkel B; Aspelin, Peter; Heuchel, Rainer; Muhammed, Mamoun; Dähne, Lars; Hassan, Moustapha

    2015-08-28

    Air-filled polyvinyl alcohol microbubbles (PVA-MBs) were recently introduced as a contrast agent for ultrasound imaging. In the present study, we explore the possibility of extending their application in multimodal imaging by labeling them with a near infrared (NIR) fluorophore, VivoTag-680. PVA-MBs were injected intravenously into FVB/N female mice and their dynamic biodistribution over 24 h was determined by 3D-fluorescence imaging co-registered with 3D-μCT imaging, to verify the anatomic location. To further confirm the biodistribution results from in vivo imaging, organs were removed and examined histologically using bright field and fluorescence microscopy. Fluorescence imaging detected PVA-MB accumulation in the lungs within the first 30 min post-injection. Redistribution to a low extent was observed in liver and kidneys at 4 h, and to a high extent mainly in the liver and spleen at 24 h. Histology confirmed PVA-MB localization in lung capillaries and macrophages. In the liver, they were associated with Kupffer cells; in the spleen, they were located mostly within the marginal-zone. Occasional MBs were observed in the kidney glomeruli and interstitium. The potential application of PVA-MBs as a contrast agent was also studied using ultrasound (US) imaging in subcutaneous and orthotopic pancreatic cancer mouse models, to visualize blood flow within the tumor mass. In conclusion, this study showed that PVA-MBs are useful as a contrast agent for multimodal imaging. PMID:26187672

  1. NIR fluorescent dyes: versatile vehicles for marker and probe applications

    Science.gov (United States)

    Patonay, Gabor; Chapman, Gala; Beckford, Garfield; Henary, Maged

    2013-02-01

    The use of the NIR spectral region (650-900 nm) is advantageous due to the inherently lower background interference and the high molar absorptivities of NIR chromophores. Near-Infrared (NIR) dyes are increasingly used in the biological and medical field. The binding characteristics of NIR dyes to biomolecules are possibly controlled by several factors, including hydrophobicity, size and charge just to mention a few parameters. Binding characteristics of symmetric carbocyanines and found that the hydrophobic nature of the NIR dye is only partially responsible for the binding strength. Upon binding to biomolecules significant fluorescence enhancement can be observed for symmetrical carbocyanines. This fluorescence amplification facilitates the detection of the NIR dye and enhances its utility as NIR reporter. This manuscript discusses some probe and marker applications of such NIR fluorescent dyes. One application discussed here is the use of NIR dyes as markers. For labeling applications the fluorescence intensity of the NIR fluorescent label can significantly be increased by enclosing several dye molecules in nanoparticles. To decrease self quenching dyes that have relatively large Stokes' shift needs to be used. This is achieved by substituting meso position halogens with amino moiety. This substitution can also serve as a linker to covalently attach the dye molecule to the nanoparticle backbone. We report here on the preparation of NIR fluorescent silica nanoparticles. Silica nanoparticles that are modified with aminoreactive moieties can be used as bright fluorescent labels in bioanalytical applications. A new bioanalytical technique to detect and monitor the catalytic activity of the sulfur assimilating enzyme using NIR dyes is reported as well. In this spectroscopic bioanalytical assay a family of Fischer based n-butyl sulfonate substituted dyes that exhibit distinct variation in absorbance and fluorescence properties and strong binding to serum albumin as its

  2. NIR fluorescent silica nanoparticles as reporting labels in bioanalytical applications

    Science.gov (United States)

    Patonay, Gabor; Henary, Maged; Chapman, Gala; Emer, Kyle; Crow, Sydney

    2015-03-01

    prepared that has an average radius around 15 nm, contains 16-20 covalently attached dye molecules inside of the nanoparticle. The primary applications of these particles are for bright fluorescent labels that can be used in applications such as immunochemistry, flow cytometry, and many other applications.

  3. The relationship between brightness temperature and soil moisture. Selection of frequency range for microwave remote sensing

    International Nuclear Information System (INIS)

    The analysis of brightness temperature data acquired from field and aircraft experiments demonstrates a linear relationship between soil moisture and brightness temperature. However, the analysis of brightness temperature data acquired by the Skylab radiometer demonstrates a non-linear relationship between soil moisture and brightness temperature. In view of the above and also because of recent theoretical developments for the calculation of the dielectric constant and brightness temperature under varying soil moisture profile conditions, an attempt is made to study the theoretical relationship between brightness temperature and soil moisture as a function of frequency. Through the above analysis, the appropriate microwave frequency range for soil moisture studies is recommended

  4. Fluorescence uranium determination

    International Nuclear Information System (INIS)

    An equipment for analysis of uranium by fluorescence was developed in order to determine it at such a low concentration that it can not be determined by the most sensible analytical methods. this new fluorimeter was adapted to measure the fluorescence emitted by the phosphorus sodium fluoride-sodium carbonate-potasium carbonate-uranyl, being excited by ultraviolet light of 3,650 A the intensity of the light emitted was measure with a photomultiplicator RCA 5819 and the adequate electronic equipment. (Author) 19 refs

  5. Nanosecond fluorescence spectroscopy

    International Nuclear Information System (INIS)

    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

  6. Fluorescence activated cell sorting.

    Science.gov (United States)

    Bonner, W. A.; Hulett, H. R.; Sweet, R. G.; Herzenberg, L. A.

    1972-01-01

    An instrument has been developed for sorting biological cells. The cells are rendered differentially fluorescent and incorporated into a small liquid stream illuminated by a laser beam. The cells pass sequentially through the beam, and fluorescent light from the cells gives rise to electrical signals. The stream is broken into a series of uniform size drops downstream of the laser. The cell signals are used to give appropriate electrostatic charges to drops containing the cells. The drops then pass between two charged plates and are deflected to appropriate containers. The system has proved capable of providing fractions containing large numbers of viable cells highly enriched in a particular functional type.

  7. Bright and photostable push-pull pyrene dye visualizes lipid order variation between plasma and intracellular membranes

    Science.gov (United States)

    Niko, Yosuke; Didier, Pascal; Mely, Yves; Konishi, Gen-Ichi; Klymchenko, Andrey S.

    2016-01-01

    Imaging lipid organization in cell membranes requires advanced fluorescent probes. Here, we show that a recently synthesized push-pull pyrene (PA), similarly to popular probe Laurdan, changes the emission maximum as a function of lipid order, but outperforms it by spectroscopic properties. In addition to red-shifted absorption compatible with common 405 nm diode laser, PA shows higher brightness and much higher photostability than Laurdan in apolar membrane environments. Moreover, PA is compatible with two-photon excitation at wavelengths >800 nm, which was successfully used for ratiometric imaging of coexisting liquid ordered and disordered phases in giant unilamellar vesicles. Fluorescence confocal microscopy in Hela cells revealed that PA efficiently stains the plasma membrane and the intracellular membranes at >20-fold lower concentrations, as compared to Laurdan. Finally, ratiometric imaging using PA reveals variation of lipid order within different cellular compartments: plasma membranes are close to liquid ordered phase of model membranes composed of sphingomyelin and cholesterol, while intracellular membranes are much less ordered, matching well membranes composed of unsaturated phospholipids without cholesterol. These differences in the lipid order were confirmed by fluorescence lifetime imaging (FLIM) at the blue edge of PA emission band. PA probe constitutes thus a new powerful tool for biomembrane research.

  8. Fluorescence imaging under background light with a self-reset complementary metal–oxide–semiconductor image sensor

    Directory of Open Access Journals (Sweden)

    Takahiro Yamaguchi

    2015-11-01

    Full Text Available The authors propose and demonstrate the fluorescence imaging of green fluorescence protein (GFP expressed in a brain slice with a self-reset complementary metal–oxide–semiconductor image sensor under background light. By using a self-reset function to avoid pixel saturation, the weak fluorescence of GFP was successfully observed, even under background light. The result suggests that the sensor can be applied to in vivo imaging of laboratory animals during light–dark cycles, so that they can observe the different responses to bright and dark environments.

  9. Chip-scale fluorescence microscope based on a silo-filter complementary metal-oxide semiconductor image sensor.

    Science.gov (United States)

    Ah Lee, Seung; Ou, Xiaoze; Lee, J Eugene; Yang, Changhuei

    2013-06-01

    We demonstrate a silo-filter (SF) complementary metal-oxide semiconductor (CMOS) image sensor for a chip-scale fluorescence microscope. The extruded pixel design with metal walls between neighboring pixels guides fluorescence emission through the thick absorptive filter to the photodiode of a pixel. Our prototype device achieves 13 μm resolution over a wide field of view (4.8 mm × 4.4 mm). We demonstrate bright-field and fluorescence longitudinal imaging of living cells in a compact, low-cost configuration. PMID:23722754

  10. Automatic brightness and contrast adjustments for digital chest radiographs

    International Nuclear Information System (INIS)

    Digital chest radiographs are often too bright and/or lack contrast (especially those of intensive care unit patients) when viewed on a video display. Automatically adjusting the brightness and contrast reduces viewer interaction and improves displayed image quality. This paper reports on an algorithm developed that analyzes the gray-level histogram of a chest radiograph and determines the breakpoints that separate patient background, soft tissues, and dense tissues. From the breakpoint values, a piece-wise linear look-up table (LUT) is generated that reduces background contrast (this darkens the image), maintains soft- tissue contrast, and increases dense-tissue contrast (for example, in the mediastinum and subdiaphragm). The resulting UT is applied to the original image via video display

  11. Improvement in brightness of multicusp-plasma ion source

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Q.; Jiang, X.; King, T-J.; Leung, K-N.; Standiford, K.; Wilde, S.B.

    2002-05-24

    The beam brightness of a multicusp-plasma ion source has been substantially improved by optimizing the source configuration and extractor geometry. The current density of a 2 keV He{sup +} beam extracted from a 7.5-cm-diameter source operating at 2.5 kW RF power is {approx}100 mA/cm{sup 2}, which is {approx}10 times larger than that of a beam extracted from a 5-cm-diameter source operating at 1 kW RF power. A smaller focused beam spot size is achieved with a counter-bored extractor instead of a conventional (''through-hole'') extractor, resulting another order of magnitude improvement in beam current density. Measured brightness can be as high as 440 A/cm{sup 2}Sr, which represents a 30 times improvement over prior work.

  12. Temporal properties of bright BGO GRBs detected by Fermi

    CERN Document Server

    Bissaldi, Elisabetta; Longo, Francesco

    2015-01-01

    We present results of an analysis of a sample of bright Gamma-Ray Bursts (GRBs) detected by Fermi-GBM up to more than 1 MeV, which were collected during six years of Fermi operations. In particular, we focus on the GRB durations over several energy bands of the prompt emission of a subsample of bright GRBs detected up to 10 MeV by GBM and, when possible, up to 1 GeV by Fermi-LAT, thus expanding the Duration-Energy relationship in GRB light curves to high energies for the first time. We find that the relationship for these energetic GRBs is flatter than reported for other samples, suggesting that the high- and low-energy emission mechanisms are closely related.

  13. BRITE-Constellation: Nanosatellites for Precision Photometry of Bright Stars

    CERN Document Server

    Weiss, W W; Schwarzenberg-Czerny, A; Koudelka, O F; Grant, C C; Zee, R E; Kuschnig, R; Mochnacki, St; Rucinski, S M; Matthews, J M; Orleanski, P; Pamyatnykh, A; Pigulski, A; Alves, J; Guedel, M; Handler, G; Wade, G A; Scholtz, A L

    2013-01-01

    BRITE-Constellation (where BRITE stands for BRIght Target Explorer) is an international nanosatellite mission to monitor photometrically, in two colours, brightness and temperature variations of stars brighter than V = 4. The current mission design consists of three pairs of 7 kg nanosats from Austria, Canada and Poland carrying optical telescopes and CCDs. One instrument in each pair is equipped with a blue filter; the other, a red filter. The first two nanosats are UNIBRITE, designed and built by University of Toronto Institute for Aerospace Studies - Space Flight Laboratory and its twin, BRITE-Austria, built by the Technical University Graz with support of UTIAS-SFL. They were launched on 25 February 2013 by the Indian Space Agency under contract to the Canadian Space Agency into a low-Earth dusk-dawn polar orbit.

  14. Bright solitons in a PT-symmetric chain of dimers

    CERN Document Server

    Kirikchi, Omar B; Susanto, Hadi

    2016-01-01

    We study the existence and stability of fundamental bright discrete solitons in a parity-time (PT)-symmetric coupler composed by a chain of dimers, that is modelled by linearly coupled discrete nonlinear Schrodinger equations with gain and loss terms. We use a perturbation theory for small coupling between the lattices to perform the analysis, which is then confirmed by numerical calculations. Such analysis is based on the concept of the so-called anti-continuum limit approach. We consider the fundamental onsite and intersite bright solitons. Each solution has symmetric and antisymmetric configurations between the arms. The stability of the solutions is then determined by solving the corresponding eigenvalue problem. We obtain that both symmetric and antisymmetric onsite mode can be stable for small coupling, on the contrary of the reported continuum limit where the antisymmetric solutions are always unstable. The instability is either due to the internal modes crossing the origin or the appearance of a quart...

  15. The brightness and spatial distributions of terrestrial radio sources

    CERN Document Server

    Offringa, A R; Zaroubi, S; Koopmans, L V E; Wijnholds, S J; Abdalla, F B; Brouw, W N; Ciardi, B; Iliev, I T; Harker, G J A; Mellema, G; Bernardi, G; Zarka, P; Ghosh, A; Alexov, A; Anderson, J; Asgekar, A; Avruch, I M; Beck, R; Bell, M E; Bell, M R; Bentum, M J; Best, P; Bîrzan, L; Breitling, F; Broderick, J; Brüggen, M; Butcher, H R; de Gasperin, F; de Geus, E; de Vos, M; Duscha, S; Eislöffel, J; Fallows, R A; Ferrari, C; Frieswijk, W; Garrett, M A; Grießmeier, J; Hassall, T E; Horneffer, A; Iacobelli, M; Juette, E; Karastergiou, A; Klijn, W; Kondratiev, V I; Kuniyoshi, M; Kuper, G; van Leeuwen, J; Loose, M; Maat, P; Macario, G; Mann, G; McKean, J P; Meulman, H; Norden, M J; Orru, E; Paas, H; Pandey-Pommier, M; Pizzo, R; Polatidis, A G; Rafferty, D; Reich, W; van Nieuwpoort, R; Röttgering, H; Scaife, A M M; Sluman, J; Smirnov, O; Sobey, C; Tagger, M; Tang, Y; Tasse, C; ter Veen, S; Toribio, C; Vermeulen, R; Vocks, C; van Weeren, R J; Wise, M W; Wucknitz, O

    2013-01-01

    Faint undetected sources of radio-frequency interference (RFI) might become visible in long radio observations when they are consistently present over time. Thereby, they might obstruct the detection of the weak astronomical signals of interest. This issue is especially important for Epoch of Reionisation (EoR) projects that try to detect the faint redshifted HI signals from the time of the earliest structures in the Universe. We explore the RFI situation at 30-163 MHz by studying brightness histograms of visibility data observed with LOFAR, similar to radio-source-count analyses that are used in cosmology. An empirical RFI distribution model is derived that allows the simulation of RFI in radio observations. The brightness histograms show an RFI distribution that follows a power-law distribution with an estimated exponent around -1.5. With several assumptions, this can be explained with a uniform distribution of terrestrial radio sources whose radiation follows existing propagation models. Extrapolation of t...

  16. VLA observations of the Palomar bright quasar survey

    International Nuclear Information System (INIS)

    The authors have optically surveyed some 10000 square degrees of the northern sky to search for bright quasars. Their final sample contains about 100 quasars. The B magnitudes of the sample range from 13.1 to 16.5, with most in the range 15.0-16.2. The redshifts range from 0.03 to over 2, considerably concentrated toward smaller values (median of 0.18). They observed 94 of these quasars with the partially complete VLA in November/December 1979, and detected radio emission from 27 of them, or 29%, to a limit of 1-2 mJy. It is concluded that bright quasars are definitely more likely to be detectable radio sources. (Auth.)

  17. Microwave Brightness Temperature and Lunar Son Dielectric Property Retrieve

    Institute of Scientific and Technical Information of China (English)

    J. Wu; D.H. Li; A.T. Altyntsev; B.I. Lubyshev

    2005-01-01

    Among many scientific objectives of lunar exploration, investigations on lunar soil become more and more attractive to the scientists duo to the existence of abundant 3He and ilmenite in the lunar soil and their possible utilization. Although the soil composition determination on the lunar surface is available by visible light spectrometer, γ/X-ray spectrometer etc, the evaluations on the total reserves of 3He and ilmenite in the lunar deep and on the thickness of the lunar soil are still impossible so far. In this paper, the authors first give a rough analysis of the microwave brightness temperature images of the lunar disc observed using the NRAO 12 Meter Telescope and Siberian Solar Radio Telescope; then introduce our researches on the microwave dielectric properties of lunar soil simulators; finally, discuss some basic relations between the microwave brightness temperature and lunar soil properties.

  18. Microwave brightness temperature imaging and dielectric properties of lunar soil

    Indian Academy of Sciences (India)

    Wu Ji; Li Dihui; Zhang Xiaohui; Jiang Jingshan; A T Altyntsev; B I Lubyshev

    2005-12-01

    Among many scientific objectives of lunar exploration, investigations on lunar soil become attractive due to the existence of He3 and ilmenite in the lunar soil and their possible utilization as nuclear fuel for power generation.Although the composition of the lunar surface soil can be determined by optical and /X-ray spectrometers, etc., the evaluation of the total reserves of He3 and ilmenite within the regolith and in the lunar interior are still not available.In this paper,we give a rough analysis of the microwave brightness temperature images of the lunar disc observed using the NRAO 12 meter Telescope and Siberian Solar Radio Telescope.We also present the results of the microwave dielectric properties of terrestrial analogues of lunar soil and,discuss some basic relations between the microwave brightness temperature and lunar soil properties.

  19. Sunspot bright rings and the thermal diffusivity of solar convection

    Science.gov (United States)

    Duvall, T., Jr.; Fowler, L. A.; Foukal, P.

    1983-01-01

    Raster-scan observations of 10 sunspots, made in 1980 and 1981 with the 512-channel diode array and vacuum telescope at the Kitt Peak National Observatory, are reported. Data from several 10-min scans of 0.25-A passbands of clean continuum were summed to give an rms noise level of 0.25 percent, corrected by applying a limb-darkening curve, and analyzed to determine the average intensity for each of eight segments of a series of concentric rings around each sunspot. Faculae and pores were identified and discarded in constructing radial intensity profiles. Marginally significant bright symmetric rings (peak amplitude 0.1-0.3 percent) not attributable to residual facular signal or instrumental effects were observed around 6 of 10 sunspots. No evidence of more intense bright rings was found. These findings are discussed in terms of thermal-diffusion models proposed to explain the fate of the radiative flux blocked by sunspots.

  20. Algebraic bright and vortex solitons in defocusing media

    OpenAIRE

    Borovkova, Olga V.; Kartashov, Yaroslav V.; Boris A. Malomed; Torner, Lluis

    2011-01-01

    We demonstrate that spatially inhomogeneous defocusing nonlinear landscapes with the nonlinearity coefficient growing toward the periphery as [1+abs(r)]**a support one- and two-dimensional fundamental and higher-order bright solitons, as well as vortex solitons, with algebraically decaying tails. The energy flow of the solitons converges as long as nonlinearity growth rate exceeds the dimensionality, i.e., a>D. Fundamental solitons are always stable, while multipoles and vortices are stable i...

  1. Distance Measurements and Stellar Population Properties via Surface Brightness Fluctuations

    OpenAIRE

    Fritz, Alexander

    2012-01-01

    Surface Brightness Fluctuations (SBFs) are one of the most powerful techniques to measure the distance and to constrain the unresolved stellar content of extragalactic systems. For a given bandpass, the absolute SBF magnitude \\bar{M} depends on the properties of the underlying stellar population. Multi-band SBFs allow scientists to probe different stages of the stellar evolution: UV and blue wavelength band SBFs are sensitive to the evolution of stars within the hot Horizontal Branch (HB) and...

  2. Contribution of Bright Extragalactic Radio Sources to Microwave Anisotropy

    OpenAIRE

    Sokasian, Aaron; Gawiser, Eric; Smoot, George F.

    1998-01-01

    We estimate the contribution of extragalactic radio sources to fluctuations in sky temperature over the range of frequencies (10-300 GHz) used for Cosmic Microwave Background (CMB) anisotropy measurements. CMB anisotropy observations at high resolution and low frequencies are especially sensitive to this foreground. We have compiled a catalog of 2207 bright radio sources, including 758 sources with flux measurements at 90 GHz. We develop a method to extrapolate the source spectra and predict ...

  3. Bright spots among the world’s coral reefs

    Science.gov (United States)

    Cinner, Joshua E.; Huchery, Cindy; MacNeil, M. Aaron; Graham, Nicholas A. J.; McClanahan, Tim R.; Maina, Joseph; Maire, Eva; Kittinger, John N.; Hicks, Christina C.; Mora, Camilo; Allison, Edward H.; D’Agata, Stephanie; Hoey, Andrew; Feary, David A.; Crowder, Larry; Williams, Ivor D.; Kulbicki, Michel; Vigliola, Laurent; Wantiez, Laurent; Edgar, Graham; Stuart-Smith, Rick D.; Sandin, Stuart A.; Green, Alison L.; Hardt, Marah J.; Beger, Maria; Friedlander, Alan; Campbell, Stuart J.; Holmes, Katherine E.; Wilson, Shaun K.; Brokovich, Eran; Brooks, Andrew J.; Cruz-Motta, Juan J.; Booth, David J.; Chabanet, Pascale; Gough, Charlie; Tupper, Mark; Ferse, Sebastian C. A.; Sumaila, U. Rashid; Mouillot, David

    2016-07-01

    Ongoing declines in the structure and function of the world’s coral reefs require novel approaches to sustain these ecosystems and the millions of people who depend on them. A presently unexplored approach that draws on theory and practice in human health and rural development is to systematically identify and learn from the ‘outliers’—places where ecosystems are substantially better (‘bright spots’) or worse (‘dark spots’) than expected, given the environmental conditions and socioeconomic drivers they are exposed to. Here we compile data from more than 2,500 reefs worldwide and develop a Bayesian hierarchical model to generate expectations of how standing stocks of reef fish biomass are related to 18 socioeconomic drivers and environmental conditions. We identify 15 bright spots and 35 dark spots among our global survey of coral reefs, defined as sites that have biomass levels more than two standard deviations from expectations. Importantly, bright spots are not simply comprised of remote areas with low fishing pressure; they include localities where human populations and use of ecosystem resources is high, potentially providing insights into how communities have successfully confronted strong drivers of change. Conversely, dark spots are not necessarily the sites with the lowest absolute biomass and even include some remote, uninhabited locations often considered near pristine. We surveyed local experts about social, institutional, and environmental conditions at these sites to reveal that bright spots are characterized by strong sociocultural institutions such as customary taboos and marine tenure, high levels of local engagement in management, high dependence on marine resources, and beneficial environmental conditions such as deep-water refuges. Alternatively, dark spots are characterized by intensive capture and storage technology and a recent history of environmental shocks. Our results suggest that investments in strengthening fisheries

  4. Survival analysis of the optical brightness of GRB host galaxies

    CERN Document Server

    Racz, I I; Bagoly, Z; Toth, L V

    2015-01-01

    We studied the unbiased optical brightness distribution which was calculated from the survival analysis of host galaxies and its relationship with the Swift GRB data of the host galaxies observed by the Keck telescopes. Based on the sample obtained from merging the Swift GRB table and the Keck optical data we also studied the dependence of this distribution on the data of the GRBs. Finally, we compared the HGs distribution with standard galaxies distribution which is in the DEEP2 galaxies catalog.

  5. Measuring Anthropogenic Sky Glow Using a Natural Sky Brightness Model

    Science.gov (United States)

    Duriscoe, Dan M.

    2013-11-01

    Anthropogenic sky glow (a result of light pollution) combines with the natural background brightness of the night sky when viewed by an observer on the earth's surface. In order to measure the anthropogenic component accurately, the natural component must be identified and subtracted. A model of the moonless natural sky brightness in the V-band was constructed from existing data on the Zodiacal Light, an airglow model based on the van Rhijn function, and a model of integrated starlight (including diffuse galactic light) constructed from images made with the same equipment used for sky brightness observations. The model also incorporates effective extinction by the atmosphere and is improved at high zenith angles (>80°) by the addition of atmospheric diffuse light. The model may be projected onto local horizon coordinates for a given observation at a resolution of 0.05° over the hemisphere of the sky, allowing it to be accurately registered with data images obtained from any site. Zodiacal Light and integrated starlight models compare favorably with observations from remote dark sky sites, matching within ± 8 nL over 95% of the sky. The natural airglow may be only approximately modeled, errors of up to ± 25 nL are seen when the airglow is rapidly changing or has considerable character (banding); ± 8 nL precision may be expected under favorable conditions. When subtracted from all-sky brightness data images, the model significantly improves estimates of sky glow from anthropogenic sources, especially at sites that experience slight to moderate light pollution.

  6. Prediction of wood species and pulp brightness from roundwood measurements

    OpenAIRE

    Nilsson, David

    2005-01-01

    This thesis presents a number of studies, where a multivariate approach was taken to construct models that predict wood species and thermo mechanical pulp brightness from roundwood of Norway spruce and Scots pine. The first and second studies produced multivariate prediction models for wood species from the bark of spruce and pine. These models can be used for wood species classification and would replace the manual log assessment that takes place today. Principal Component Analysis, PCA, and...

  7. Night trend in average brightness of aurora discrete forms

    International Nuclear Information System (INIS)

    Using the method of imposed epochs according to the data of visual observations for many years of aurorae at the Tixi and Norilsk stations, a systematic decrease in the average brightness of aurora discrete forms in diurnal course with the increase in time elapsed after the sunset at the altitude of 200 km above the station is detected. It is assumed that the tendency is caused by the change in electric conductivity of ionospheric link of auroral current systems

  8. The brightness and spatial distributions of terrestrial radio sources

    OpenAIRE

    Offringa, A. R.; De Bruyn, A. G.; Zaroubi, S.; Koopmans, L. V. E.; Wijnholds, S. J.; Abdalla, F. B.; Brouw, W. N.; Ciardi, B.; Iliev, I. T.; Harker, G. J. A.; Mellema, G.; Bernardi, G.; Zarka, P.; Ghosh, A; Alexov, A.

    2013-01-01

    Faint undetected sources of radio-frequency interference (RFI) might become visible in long radio observations when they are consistently present over time. Thereby, they might obstruct the detection of the weak astronomical signals of interest. This issue is especially important for Epoch of Reionisation (EoR) projects that try to detect the faint redshifted HI signals from the time of the earliest structures in the Universe. We explore the RFI situation at 30-163 MHz by studying brightness ...

  9. Bright spots among the world’s coral reefs.

    Science.gov (United States)

    Cinner, Joshua E; Huchery, Cindy; MacNeil, M Aaron; Graham, Nicholas A J; McClanahan, Tim R; Maina, Joseph; Maire, Eva; Kittinger, John N; Hicks, Christina C; Mora, Camilo; Allison, Edward H; D'Agata, Stephanie; Hoey, Andrew; Feary, David A; Crowder, Larry; Williams, Ivor D; Kulbicki, Michel; Vigliola, Laurent; Wantiez, Laurent; Edgar, Graham; Stuart-Smith, Rick D; Sandin, Stuart A; Green, Alison L; Hardt, Marah J; Beger, Maria; Friedlander, Alan; Campbell, Stuart J; Holmes, Katherine E; Wilson, Shaun K; Brokovich, Eran; Brooks, Andrew J; Cruz-Motta, Juan J; Booth, David J; Chabanet, Pascale; Gough, Charlie; Tupper, Mark; Ferse, Sebastian C A; Sumaila, U Rashid; Mouillot, David

    2016-07-21

    Ongoing declines in the structure and function of the world’s coral reefs require novel approaches to sustain these ecosystems and the millions of people who depend on them3. A presently unexplored approach that draws on theory and practice in human health and rural development is to systematically identify and learn from the ‘outliers’—places where ecosystems are substantially better (‘bright spots’) or worse (‘dark spots’) than expected, given the environmental conditions and socioeconomic drivers they are exposed to. Here we compile data from more than 2,500 reefs worldwide and develop a Bayesian hierarchical model to generate expectations of how standing stocks of reef fish biomass are related to 18 socioeconomic drivers and environmental conditions. We identify 15 bright spots and 35 dark spots among our global survey of coral reefs, defined as sites that have biomass levels more than two standard deviations from expectations. Importantly, bright spots are not simply comprised of remote areas with low fishing pressure; they include localities where human populations and use of ecosystem resources is high, potentially providing insights into how communities have successfully confronted strong drivers of change. Conversely, dark spots are not necessarily the sites with the lowest absolute biomass and even include some remote, uninhabited locations often considered near pristine6. We surveyed local experts about social, institutional, and environmental conditions at these sites to reveal that bright spots are characterized by strong sociocultural institutions such as customary taboos and marine tenure, high levels of local engagement in management, high dependence on marine resources, and beneficial environmental conditions such as deep-water refuges. Alternatively, dark spots are characterized by intensive capture and storage technology and a recent history of environmental shocks. Our results suggest that investments in strengthening fisheries

  10. Developing high brightness beams for heavy ion driven inertial fusion

    OpenAIRE

    Kwan, J.W.; Ahle, L.A.; Anders, A; Bieniosek, F.M.; Chacon-Golcher, E.; Grote, D. P.; Henestroza, E.; Leung, K.N.; Molvik, A.W.

    2001-01-01

    Heavy ion fusion (HIF) drivers require large currents and bright beams. In this paper we review the two different approaches for building HIF injectors and the corresponding ion source requirements. The traditional approach uses large aperture, low current density ion sources, resulting in a very large injector system. A more recent conceptual approach merges high current density mini-beamlets into a large current beam in order to significantly reduce the size of the injector. Experimen...

  11. Concentration of bright quasars in the Sculptor Group

    International Nuclear Information System (INIS)

    Recent objective prism searches for quasars confirm the grouping of bright quasars in the direction of the Sculptor Group of galaxies. The density of such quasars with V -2. The concentration in the NGC 55, NGC 300 and NGC 253 areas is 0.65 deg-2. Around NGC 253 the density is over 20 times the average and has a chance of -4 of being accidental. (author)

  12. Production of strongly bound 39K bright solitons

    CERN Document Server

    Lepoutre, S; Boissé, A; Berthet, G; Salomon, G; Aspect, A; Bourdel, T

    2016-01-01

    We report on the production of 39 K matter-wave bright solitons, i.e., 1D matter-waves that propagate without dispersion thanks to attractive interactions. The volume of the soliton is studied as a function of the scattering length through three-body losses, revealing peak densities as high as $\\sim 5 \\times 10^{20} m^{-3}$. Our solitons, close to the collapse threshold, are strongly bound and will find applications in fundamental physics and atom interferometry.

  13. Manakins can produce iridescent and bright feather colours without melanosomes.

    Science.gov (United States)

    Igic, Branislav; D'Alba, Liliana; Shawkey, Matthew D

    2016-06-15

    Males of many species often use colourful and conspicuous ornaments to attract females. Among these, male manakins (family: Pipridae) provide classic examples of sexual selection favouring the evolution of bright and colourful plumage coloration. The highly iridescent feather colours of birds are most commonly produced by the periodic arrangement of melanin-containing organelles (melanosomes) within barbules. Melanin increases the saturation of iridescent colours seen from optimal viewing angles by absorbing back-scattered light; however, this may reduce the wide-angle brightness of these signals, contributing to a dark background appearance. We examined the nanostructure of four manakin species (Lepidothrix isidorei, L. iris, L. nattereri and L. coeruleocapilla) to identify how they produce their bright plumage colours. Feather barbs of all four species were characterized by dense and fibrous internal spongy matrices that likely increase scattering of light within the barb. The iridescent, yet pale or whitish colours of L. iris and L. nattereri feathers were produced not by periodically arranged melanosomes within barbules, but by periodic matrices of air and β-keratin within barbs. Lepidothrix iris crown feathers were able to produce a dazzling display of colours with small shifts in viewing geometry, likely because of a periodic nanostructure, a flattened barb morphology and disorder at a microstructural level. We hypothesize that iridescent plumage ornaments of male L. iris and L. nattereri are under selection to increase brightness or luminance across wide viewing angles, which may potentially increase their detectability by females during dynamic and fast-paced courtship displays in dim light environments. PMID:27307543

  14. Bright flares in supergiant fast X-ray transients

    Science.gov (United States)

    Shakura, N.; Postnov, K.; Sidoli, L.; Paizis, A.

    2014-08-01

    At steady low-luminosity states, supergiant fast X-ray transients (SFXTs) can be at the stage of quasi-spherical settling accretion on to slowly rotating magnetized neutron stars from the OB-companion winds. At this stage, a hot quasi-static shell is formed above the magnetosphere, the plasma entry rate into magnetosphere is controlled by (inefficient) radiative plasma cooling, and the accretion rate on to the neutron star is suppressed by a factor of ˜30 relative to the Bondi-Hoyle-Littleton value. Changes in the local wind velocity and density due to, e.g. clumps, can only slightly increase the mass accretion rate (a factor of ˜10) bringing the system into the Compton-cooling-dominated regime and led to the production of moderately bright flares (Lx ≲ 1036 erg s-1). To interpret the brightest flares (Lx > 1036 erg s-1) displayed by the SFXTs within the quasi-spherical settling accretion regimes, we propose that a larger increase in the mass accretion rate can be produced by sporadic capture of magnetized stellar wind plasma. At sufficiently low accretion rates, magnetic reconnection can enhance the magnetospheric plasma entry rate, resulting in copious production of X-ray photons, strong Compton cooling and ultimately in unstable accretion of the entire shell. A bright flare develops on the free-fall time-scale in the shell, and the typical energy released in an SFXT bright flare corresponds to the mass of the shell. This view is consistent with the energy released in SFXT bright flares (˜1038-1040 erg), their typical dynamic range (˜100) and with the observed dependence of these characteristics on the average unflaring X-ray luminosity of SFXTs. Thus, the flaring behaviour of SFXTs, as opposed to steady HMXBs, may be primarily related to their low X-ray luminosity allowing sporadic magnetic reconnection to occur during magnetized plasma entry into the magnetosphere.

  15. High-brightness diode-pumped waveguide lasers

    OpenAIRE

    Mackenzie, J.I.

    2003-01-01

    Reported in this thesis are advances toward high-brightness diode-pumped planar waveguide (PW) lasers. Efficient and compact planar waveguide lasers are made possible by their geometry, which is compatible with that of high-power diode lasers, has very good thermal management characteristics, and delivers high optical gains per unit pump power. Thus using the waveguide structure in conjunction with trivalent rare-earth ions, multi-Watt diffraction-limited operation of weak and quasi-three-lev...

  16. Ultraviolet fluorescence monitor

    Energy Technology Data Exchange (ETDEWEB)

    Hargis, P.J. Jr.; Preppernau, B.L.; Aragon, B.P. [Sandia National Labs., Albuquerque, NM (United States). Laser, Optics and Remote Sensing Dept.

    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.

  17. Yeast fluorescence microscopy

    Czech Academy of Sciences Publication Activity Database

    Hašek, Jiří

    New Jersey : Humana Press, 2005, s. 85-96. ISBN 1-59259-958-3 R&D Projects: GA AV ČR IAA5020102; GA ČR GA204/02/1424 Institutional research plan: CEZ:AV0Z50200510 Keywords : yeast * fluorescence microscopy * immunofluorescence Subject RIV: EE - Microbiology, Virology

  18. Brightness limitations in multi-kiloampere electron beam sources

    International Nuclear Information System (INIS)

    Heuristic relationships such as the Lawson-Penner criterion, used to scale Free Electron Laser (FEL) amplifier gain and efficiency over orders of magnitude in beam current and brightness, have no fundamental basis. The brightness of a given source is set by practical design choices such as peak voltage, cathode type, gun electrode geometry, and focusing field topology. The design of low emittance, high current electron guns has received considerable attention at Livermore over the past few years. The measured brightnesses of the Experimental Test Accelerator (ETA) and Advanced Test Accelerator (ATA) guns are less than predicted with the EBQ gun design code; this discrepancy is due to plasma effects from the present cold, plasma cathode in the code. The EBQ code is well suited to exploring the current limits of gridless relativistic Pierce columns with moderate current density (2) at the cathode. As EBQ uses a steady-state calculation it is not amenable for study of transient phenomena at the beam head. For this purpose, a Darwin approximation code, DPC, has been written. The main component in our experimental cathode development effort is a readily modified electron gun that will allow us to test many candidate cathode materials, types and electrode geometries at field stresses up to 1 MV/cm. 6 references, 6 figures

  19. HSV Brightness Factor Matching for Gesture Recognition System

    Directory of Open Access Journals (Sweden)

    Mokhtar M. Hasan

    2010-12-01

    Full Text Available The main goal of gesture recognition research is to establish a system which can identify specific human gestures and use these identified gestures to be carried out by the machine, In this paper, we introduce a new method for gesture recognition that based on computing the local brightness for each block of the gesture image, the gesture image is divided into 25x25 blocks each of 5x5 block size, and we calculated the local brightness of each block, so, each gesture produces 25x25 features value, our experimental shows that more that %60 of these features are zero value which leads to minimum storage space, this brightness value is calculated from the HSV (Hue, Saturation and Value color model that used for segmentation operation, the recognition rate achieved is %91 using 36 training gestures and 24 different testing gestures. This Paper focuses on the hand gesture instead of the whole body movement since hands are the most flexible part of the body and can transfer the most meaning, we build a gesture recognition system that can communicate with the machine in natural way without any mechanical devices and without using the normal input devices which are the keyboard and mouse and the mathematical equations will be the translator between the gestures and the telerobotic.

  20. Giant Low Surface Brightness Galaxies: Evolution in Isolation

    Indian Academy of Sciences (India)

    M. Das

    2013-03-01

    Giant Low Surface Brightness (GLSB) galaxies are amongst the most massive spiral galaxies that we know of in our Universe. Although they fall in the class of late type spiral galaxies, their properties are far more extreme. They have very faint stellar disks that are extremely rich in neutral hydrogen gas but low in star formation and hence low in surface brightness. They often have bright bulges that are similar to those found in early type galaxies. The bulges can host low luminosity Active Galactic Nuclei (AGN) that have relatively low mass black holes. GLSB galaxies are usually isolated systems and are rarely found to be interacting with other galaxies. In fact many GLSB galaxies are found under dense regions close to the edges of voids. These galaxies have very massive dark matter halos that also contribute to their stability and lack of evolution. In this paper we briefly review the properties of this unique class of galaxies and conclude that both their isolation and their massive dark matter halos have led to the low star formation rates and the slower rate of evolution in these galaxies.

  1. South African night sky brightness during high aerosol epochs

    CERN Document Server

    Winkler, Hartmut; Marang, Fred

    2014-01-01

    Sky conditions in the remote, dry north-western interior of South Africa are now the subject of considerable interest in view of the imminent construction of numerous solar power plants in this area. Furthermore, the part of this region in which the core of the SKA is to be located (which includes SALT) has been declared an Astronomical Advantage Zone, for which sky brightness monitoring will now be mandatory. In this project we seek to characterise the sky brightness profile under a variety of atmospheric conditions. Key factors are of course the lunar phase and altitude, but in addition the sky brightness is also significantly affected by the atmospheric aerosol loading, as that influences light beam scattering. In this paper we chose to investigate the sky characteristics soon after the Mount Pinatubo volcanic eruption in 1991, which resulted in huge ash masses reaching the stratosphere (where they affected solar irradiance for several years). We re-reduced photometric sky measurements from the South Afric...

  2. BRITE-Constellation: nanosatellites for precision photometry of bright stars

    CERN Document Server

    Weiss, W W; Moffat, A F J; Schwarzenberg-Czerny, A; Koudelka, O F; Grant, C C; Zee, R E; Kuschnig, R; Mochnacki, St; Matthews, J M; Orleanski, P; Pamyatnykh, A; Pigulski, A; Alves, J; Guedel, M; Handler, G; Wade, G A; Zwintz, K; CCD,

    2014-01-01

    BRITE-Constellation (where BRITE stands for BRIght Target Explorer) is an international nanosatellite mission to monitor photometrically, in two colours, the brightness and temperature variations of stars generally brighter than mag(V) ~ 4, with precision and time coverage not possible from the ground. The current mission design consists of six nanosats (hence Constellation): two from Austria, two from Canada, and two from Poland. Each 7 kg nanosat carries an optical telescope of aperture 3 cm feeding an uncooled CCD. One instrument in each pair is equipped with a blue filter, the other with a red filter. Each BRITE instrument has a wide field of view (~24 degrees), so up to about 15 bright stars can be observed simultaneously, sampled in 32 pixel x 32 pixel sub-rasters. Photometry of additional fainter targets, with reduced precision but thorough time sampling, will be possible through onboard data processing. The BRITE sample is dominated by the most intrinsically luminous stars: massive stars seen at all e...

  3. Estimation of the Space Density of Low Surface Brightness Galaxies

    CERN Document Server

    Briggs, F H

    1997-01-01

    The space density of low surface brightness and tiny gas-rich dwarf galaxies are estimated for two recent catalogs: The Arecibo Survey of Northern Dwarf and Low Surface Brightness Galaxies (Schneider, Thuan, Magri & Wadiak 1990) and The Catalog of Low Surface Brightness Galaxy, List II (Schombert, Bothun, Schneider & McGaugh 1992). The goals are (1) to evaluate the additions to the completeness of the Fisher and Tully (1981) 10 Mpc Sample and (2) to estimate whether the density of galaxies contained in the new catalogs adds a significant amount of neutral gas mass to the the inventory of HI already identified in the nearby, present-epoch universe. Although tiny dwarf galaxies (M_HI < ~10^7 solar masses) may be the most abundant type of extragalactic stellar system in the nearby Universe, if the new catalogs are representative, the LSB and dwarf populations they contain make only a small addition (<10%) to the total HI content of the local Universe and probably constitute even smaller fractions o...

  4. Night-sky brightness and extinction at Mt. Shatdzhatmaz

    CERN Document Server

    Kornilov, V; Voziakova, O; Shatsky, N; Safonov, B; Gorbunov, I; Potanin, S; Cheryasov, D; Senik, V

    2016-01-01

    The photometric sky quality of Mt. Shatdzhatmaz, the site of Sternberg Astronomical Institute Caucasian Observatory 2.5 m telescope, is characterized here by the statistics of the night-time sky brightness and extinction. The data were obtained as a by-product of atmospheric optical turbulence measurements with the MASS (Multi-Aperture Scintillation Sensor) device conducted in 2007--2013. The factors biasing night-sky brightness measurements are considered and a technique to reduce their impact on the statistics is proposed. The single-band photometric estimations provided by MASS are easy to transform to the standard photometric bands. The median moonless night-sky brightness is 22.1, 21.1, 20.3, and 19.0 mag per square arcsec for the $B$, $V$, $R$, and $I$ spectral bands, respectively. The median extinction coefficients for the same photometric bands are 0.28, 0.17, 0.13, and 0.09 mag. The best atmospheric transparency is observed in winter.

  5. A Spectroscopic Reconnaissance of UV-Bright Stars

    CERN Document Server

    Eracleous, M; Mateen, M; Lanning, H H

    2001-01-01

    We have carried out spectroscopic observations and made preliminary classifications of 62 UV-bright stars identified by Lanning on plates taken by A. Sandage. The goal was to search for "interesting" objects, such as emission-line stars, hot sub-dwarfs, and high-gravity stars. Our targets were grouped into two samples, a bright, B < 13, sample of 35 stars observed with the Kitt Peak 2.1m telescope and a faint, 13< B < 16, sample of 27 stars observed with the Hobby-Eberly Telescope. We find 39% fairly normal O-mid B stars, 15% late ~B-late A stars and 32% F-G stars, with 13% of the stars being high gravity objects, composite, or otherwise peculiar. Included are four emission-line stars, three composite systems. Thus one out of every ten Lanning stars is "interesting" and may deserve individual study. Stars in the bright sample are often found to be late F or early G stars, although this sample does include interesting stars as well. No such large contamination occurs among the fainter stars, however, ...

  6. Bright Soil Churned by Spirit's Sol 1861 Drive

    Science.gov (United States)

    2009-01-01

    NASA's Mars Exploration Rover Spirit drove 22.7 meters (74 feet) toward the southwest on the 1,861st Martian day, or sol, of Spirit's mission on Mars (March 28, 2009). After the drive, the rover took this image with its front hazard-avoidance camera, looking back at the tracks from the drive. As usual since losing the use of its right-front wheel in 2006, Spirit drove backwards. The immobile right-front wheel churned up a long stripe of bright soil during this drive. Where Spirit has found such bright soil in the past, subsequent analysis of the composition found concentrations of sulfur or silica that testified to past action of water at the site. When members of the rover team saw the large quantity of bright soil exposed by the Sol 1861 drive, they quickly laid plans to investigate the composition with Spirit's alpha particle X-ray spectrometer. The Sol 1861 drive took the rover past the northwest corner of the low plateau called 'Home Plate,' making progress on a route around the western side of Home Plate. The edge of Home Plate forms the horizon on the right side of this image. Husband Hill is on the horizon on the left side. For scale, the parallel rover wheel tracks are about 1 meter (40 inches) apart. The rover's hazard-avoidance cameras take 'fisheye' wide-angle images.

  7. Statistical filtering in fluorescence microscopy and fluorescence correlation spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Macháň, Radek; Kapusta, Peter; Hof, Martin

    2014-01-01

    Roč. 406, č. 20 (2014), s. 4797-4813. ISSN 1618-2642 R&D Projects: GA ČR GBP208/12/G016 Institutional support: RVO:61388955 Keywords : Filtered fluorescence correlation spectroscopy * Fluorescence lifetime correlation spectroscopy * Fluorescence spectral correlation spectroscopy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.436, year: 2014

  8. DNA fluorescence shift sensor: a rapid method for the detection of DNA hybridization using silver nanoclusters.

    Science.gov (United States)

    Lee, Shin Yong; Hairul Bahara, Nur Hidayah; Choong, Yee Siew; Lim, Theam Soon; Tye, Gee Jun

    2014-11-01

    DNA-templated silver nanoclusters (AgNC) are a class of subnanometer sized fluorophores with good photostability and brightness. It has been applied as a diagnostic tool mainly for deoxyribonucleic acid (DNA) detection. Integration of DNA oligomers to generate AgNCs is interesting as varying DNA sequences can result in different fluorescence spectra. This allows a simple fluorescence shifting effect to occur upon DNA hybridization with the hybridization efficiency being a pronominal factor for successful shifting. The ability to shift the fluorescence spectra as a result of hybridization overcomes the issue of background intensities in most fluorescent based assays. Here we describe an optimized method for the detection of single-stranded and double-stranded synthetic forkhead box P3 (FOXP3) target by hybridization with the DNA fluorescence shift sensor. The system forms a three-way junction by successful hybridization of AgNC, G-rich strand (G-rich) to the target DNA, which generated a shift in fluorescence spectra with a marked increase in fluorescence intensity. The DNA fluorescence shift sensor presents a rapid and specific alternative to conventional DNA detection. PMID:25129336

  9. Functionalized manganese-doped zinc sulfide quantum dot-based fluorescent probe for zinc ion

    International Nuclear Information System (INIS)

    We report on a simple strategy for the determination of zinc ion by using surface-modified quantum dots. The probe consists of manganese-doped quantum dots made from zinc sulfide and capped N-acetyl-L-cysteine. The particles exhibit bright yellow-orange emission with a peak at 598 nm which can be attributed to the 4T1→6A1 transition of Mn(II). This bright fluorescence is effectively quenched by modifying the sulfur anion which suppresses the radiative recombination process. The emission of the probe can then be restored by adding Zn(II) which causes the formation of a ZnS passivation layer around the QDs. The fluorescence enhancement caused is linear in the 1. 25 to 30 μM zinc concentration range, and the limit of detection is 0. 67 μM. (author)

  10. Two-dimensional bright and dark-in-bright dipolar Bose–Einstein condensate solitons on a one-dimensional optical lattice

    Science.gov (United States)

    Adhikari, S. K.

    2016-08-01

    We study the statics and dynamics of anisotropic, stable, bright and dark-in-bright dipolar quasi-two-dimensional Bose–Einstein condensate (BEC) solitons on a one-dimensional (1D) optical-lattice (OL) potential. These solitons mobile in a plane perpendicular to a 1D OL trap can have both repulsive and attractive contact interactions. Dark-in-bright solitons are the excited states of bright solitons. The solitons, when subjected to a small perturbation, exhibit sustained breathing oscillation. Dark-in-bright solitons can be created by phase imprinting a bright soliton. At medium velocities the collision between two solitons is found to be quasi-elastic. Results are demonstrated by a numerical simulation of the three-dimensional mean-field Gross–Pitaevskii equation in three spatial dimensions employing realistic interaction parameters for a dipolar 164Dy BEC.

  11. Fluorescent Structural DNA Nanoballs Functionalized With Phosphate-Linked Nucleotide Triphosphates

    Science.gov (United States)

    Anderson, Jon P.; Reynolds, Bambi L.; Baum, Kristin; Williams, John G.

    2010-01-01

    Highly labeled DNA nanoballs functionalized with phosphate-linked nucleotide triphosphates (dNTPs) were developed as a source of dNTPs for DNA polymerase. The particles were prepared by strand-displacement polymerization from a self-complementary circular template. Imaged by atomic force microscopy, these functionalized particles appear as condensed fuzzy balls with diameters between 50–150 nm. They emit a bright fluorescent signal, detected in 2 msec exposures with a signal-to-noise of 25 when imaged using a TIR fluorescence microscope. PMID:20158249

  12. Wave and Wind Direction Effects on SFMR Brightness Temperatures

    Science.gov (United States)

    Holbach, Heather; Uhlhorn, Eric; Bourassa, Mark

    2015-04-01

    Surface winds in a tropical cyclone are essential for determining its strength. Currently the Stepped-Frequency Microwave Radiometer (SFMR) and Global Positioning System (GPS) dropwindsondes are the main instruments used for obtaining in situ surface wind measurements. The platforms for these instruments are the National Oceanographic and Atmospheric Administration (NOAA) P-3 and Air Force C-130J hurricane hunter aircraft. The SFMR measures sea surface microwave brightness temperatures at six frequencies ranging from 4.7 to 7.2 GHz. Surface wind speed estimates are obtained from these brightness temperatures by using a retrieval algorithm that employs a geophysical model function relating surface emissivity and wind speed. The SFMR is designed to obtain a single nadir track of surface wind speeds directly beneath the aircraft during level flight and not when turning because of the complexity of the wave field and foam distribution when the SFMR views the surface off-nadir or during aircraft rolls. However, the effects of the wave field on the measurements can be investigated using measurements obtained during the 2008 and 2014 Atlantic hurricane seasons. An SFMR module was flown in precipitation-free regions of the tropical cyclones to collect data at specified roll angles of 15°, 30°, 45°, and 60° in some cases. Excess brightness temperatures are then calculated with respect to zero wind speed values and independent of wind direction. An asymmetry is found in the resulting excess brightness temperatures. It is hypothesized that this asymmetry is caused by the direction of wave propagation and the angle at which the wave field is viewed by the SFMR. Wind direction may also play a role in the asymmetry. To analyze the asymmetry further measurement from WindSat will be used. Once the relationship is determined between surface wind speed, brightness temperature, and incidence angle a technique will be developed to obtain a surface wind speed when the aircraft is

  13. Green fluorescent protein: A perspective

    OpenAIRE

    Remington, S James

    2011-01-01

    A brief personal perspective is provided for green fluorescent protein (GFP), covering the period 1994–2011. The topics discussed are primarily those in which my research group has made a contribution and include structure and function of the GFP polypeptide, the mechanism of fluorescence emission, excited state protein transfer, the design of ratiometric fluorescent protein biosensors and an overview of the fluorescent proteins derived from coral reef animals. Structure-function relationship...

  14. Efficacy of a single sequence of intermittent bright light pulses for delaying circadian phase in humans. : Phase delaying efficacy of intermittent bright light

    OpenAIRE

    Gronfier, Claude; Wright, Kenneth,; Kronauer, Richard,; Jewett, Megan,; Czeisler, Charles,

    2004-01-01

    International audience It has been shown in animal studies that exposure to brief pulses of bright light can phase shift the circadian pacemaker and that the resetting action of light is most efficient during the first minutes of light exposure. In humans, multiple consecutive days of exposure to brief bright light pulses have been shown to phase shift the circadian pacemaker. The aim of the present study was to determine whether a single sequence of brief bright light pulses administered ...

  15. A large sample of low surface brightness disc galaxies from the SDSS- II. Metallicities in surface brightness bins

    CERN Document Server

    Liang, Y C; Hammer, F; Chen, X Y; Liu, F S; Gao, D; Hu, J Y; Deng, L C; Zhang, B

    2010-01-01

    We study the spectroscopic properties of a large sample of Low Surface Brightness galaxies (LSBGs) (with B-band central surface brightness mu0(B)>22 mag arcsec^(-2)) selected from the Sloan Digital Sky Survey Data Release 4 (SDSS-DR4) main galaxy sample. A large sample of disk-dominated High Surface Brightness galaxies (HSBGs, with mu0(B)<22 mag arcsec^(-2)) are also selected for comparison simultaneously. To study them in more details, these sample galaxies are further divided into four subgroups according to mu0(B) (in units of mag arcsec^(-2)): vLSBGs (24.5-22.75),iLSBGs (22.75-22.0), iHSBGs (22.0-21.25), and vHSBGs (<21.25). The diagnostic diagram from spectral emission-line ratios shows that the AGN fractions of all the four subgroups are small (<9%). The 21,032 star-forming galaxies with good quality spectroscopic observations are further selected for studying their dust extinction, strong-line ratios, metallicities and stellar mass-metallicities relations. The vLSBGs have lower extinction valu...

  16. Synthesis and Fluorescence Spectra of Triazolylcoumarin Fluorescent Dyes

    Institute of Scientific and Technical Information of China (English)

    PENG Xian-fu; LI Hong-qi

    2009-01-01

    Much attention is devoted to fluorescent dyes especially those with potential in versatile applications. Reactions under "click" conditions between nonfluorescent 3 - azidocoumarins and terminal alkynes produced 3 -(1, 2, 3- triazol- 1 - yl)cournarins, a novel type of fluorescent dyes with intense fluorescence. The structures of the new coumarins were characterized by 1H NMR, MS, and IR spectra. Fluorescence spectra measurement demonstrated excellent fluorescence performance of the triazolylcoumarins and this click reaction is a promising candidate for bioconjugation and bioimaging applications since both azide and alkynes are quite inert to biological systems.

  17. Automatic cell detection in bright-field microscopy for microbeam irradiation studies

    International Nuclear Information System (INIS)

    Automatic cell detection in bright-field illumination microscopy is challenging due to cells’ inherent optical properties. Applications including individual cell microbeam irradiation demand minimisation of additional cell stressing factors, so contrast-enhancing fluorescence microscopy should be avoided. Additionally, the use of optically non-homogeneous substrates amplifies the problem. This research focuses on the design of a method for automatic cell detection on polypropylene substrate, suitable for microbeam irradiation. In order to fulfil the relative requirements, the Harris corner detector was employed to detect apparent cellular features. These features-corners were clustered based on a dual-clustering technique according to the density of their distribution across the image. Weighted centroids were extracted from the clusters of corners and constituted the targets for irradiation. The proposed method identified more than 88% of the 1,738 V79 Chinese hamster cells examined. Moreover, a processing time of 2.6 s per image fulfilled the requirements for a near real-time cell detection-irradiation system. (paper)

  18. Automatic cell detection in bright-field microscopy for microbeam irradiation studies

    Science.gov (United States)

    Georgantzoglou, A.; Merchant, M. J.; Jeynes, J. C. G.; Wéra, A.-C.; Kirkby, K. J.; Kirkby, N. F.; Jena, R.

    2015-08-01

    Automatic cell detection in bright-field illumination microscopy is challenging due to cells’ inherent optical properties. Applications including individual cell microbeam irradiation demand minimisation of additional cell stressing factors, so contrast-enhancing fluorescence microscopy should be avoided. Additionally, the use of optically non-homogeneous substrates amplifies the problem. This research focuses on the design of a method for automatic cell detection on polypropylene substrate, suitable for microbeam irradiation. In order to fulfil the relative requirements, the Harris corner detector was employed to detect apparent cellular features. These features-corners were clustered based on a dual-clustering technique according to the density of their distribution across the image. Weighted centroids were extracted from the clusters of corners and constituted the targets for irradiation. The proposed method identified more than 88% of the 1,738 V79 Chinese hamster cells examined. Moreover, a processing time of 2.6 s per image fulfilled the requirements for a near real-time cell detection-irradiation system.

  19. Solving the riddle of the bright mismatches hybridization in oligonucleotide arrays

    CERN Document Server

    Naef, F; Naef, Felix; Magnasco, Marcelo O.

    2002-01-01

    HDONA technology is predicated on two ideas. First, the differential between high-affinity (perfect match, PM) and lower-affinity (mismatch, MM) probes is used to minimize cross-hybridization. Second, several short probes along the transcript are combined, introducing redundancy. Both ideas have shown problems in practice: MMs are often brighter than PMs, and it is hard to combine the pairs because their brightness often spans decades. Previous analysis suggested these problems were sequence-related; publication of the probe sequences has permitted us an in-depth study of this issue. Our results suggest that fluorescently labeling the nucleotides interferes with mRNA binding, causing a catch-22 since, to be detected, the target mRNA must both glow and stick to its probe: without labels it cannot be seen even if bound, while with too many it won't bind. We show that this conflict causes much of the complexity of HDONA raw data, suggesting that an accurate physical understanding of hybridization by incorporatin...

  20. Collision induced splitting of bright soliton in Bose-Einstein condensate

    Institute of Scientific and Technical Information of China (English)

    Wang Yue-Yue; Zhang Jie-Fang

    2009-01-01

    This paper studies the collision dynamics of bright soliton in Bose-Einstein condensate with trapezoid potential. It is found that besides the total reflection and total transmission, one bright soliton can be divided into two bright solitons with different amplitudes in a controllable manner.

  1. Fluorescence nanoscopy. Methods and applications

    OpenAIRE

    Requejo-Isidro, Jose

    2013-01-01

    Fluorescence nanoscopy refers to the experimental techniques and analytical methods used for fluorescence imaging at a resolution higher than conventional, diffraction-limited, microscopy. This review explains the concepts behind fluorescence nanoscopy and focuses on the latest and promising developments in acquisition techniques, labelling strategies to obtain highly detailed super-resolved images and in the quantitative methods to extract meaningful information from them.

  2. Fluorescence spectroscopy of dental calculus

    International Nuclear Information System (INIS)

    The aim of the present study was to investigate the fluorescence properties of dental calculus in comparison with the properties of adjacent unaffected tooth structure using both lasers and LEDs in the UV-visible range for fluorescence excitation. The influence of calculus color on the informative signal is demonstrated. The optimal spectral bands of excitation and registration of the fluorescence are determined

  3. Color center fluorescence and spin manipulation in single crystal, pyramidal diamond tips

    CERN Document Server

    Nelz, Richard; Opaluch, Oliver; Sonusen, Selda; Savenko, Natalia; Podgursky, Vitali; Neu, Elke

    2016-01-01

    We investigate bright fluorescence of nitrogen (NV)- and silicon-vacancy color centers in pyramidal, single crystal diamond tips which are commercially available as atomic force microscope probes. We coherently manipulate NV electronic spin ensembles with $T_2 = 7.7(3)\\,\\mu$s. Color center lifetimes in different tip heights indicate effective refractive index effects and quenching. Using numerical simulations, we verify enhanced photon rates from emitters close to the pyramid apex; a situation promising for scanning probe sensing.

  4. Red fluorescent proteins for imaging Zymoseptoria tritici during invasion of wheat ☆

    OpenAIRE

    Schuster, M.; Kilaru, S.; Guo, M.; Sommerauer, M; Lin, C.; Steinberg, G

    2015-01-01

    Highlights • We investigate brightness and photo-stability of RFPs in live Z. tritici cells. • mCherry is most useful in epi-fluorescence and confocal laser scanning microscopy. • The combination of mCherry and an orange-shifted filter set proves to provide brightest signals. • We provide 4 vectors with various mRFPs for yeast recombination based cloning. • The vectors carry carboxin resistance and integrate as single copies into the sdi1 locus.

  5. A Technical Note on Quantum Dots for Multi-Color Fluorescence in situ Hybridization

    OpenAIRE

    Müller, Stefan; Cremer, M; Neusser, M; Grasser, F.; T Cremer

    2009-01-01

    Quantum dots (Qdots) are semiconductor nanocrystals, which are photo-stable, show bright fluorescence with narrow, symmetric emission spectra and are available in multiple resolvable colors. We established a FISH protocol for the simultaneous visualization of up to 6 different DNA probes differentially labeled with Qdots and with conventional organic fluorochromes. Using a Leica SP5 laser scanning confocal microscope for image capture, we tested various combinations of hapten-labeled probes d...

  6. Preparation and Characterization of Highly Fluorescent, Glutathione-coated Near Infrared Quantum Dots for in Vivo Fluorescence Imaging

    Directory of Open Access Journals (Sweden)

    Yoshichika Yoshioka

    2008-10-01

    Full Text Available Fluorescent probes that emit in the near-infrared (NIR, 700-1,300 nm region are suitable as optical contrast agents for in vivo fluorescence imaging because of low scattering and absorption of the NIR light in tissues. Recently, NIR quantum dots (QDs have become a new class of fluorescent materials that can be used for in vivo imaging. Compared with traditional organic fluorescent dyes, QDs have several unique advantages such as size- and composition-tunable emission, high brightness, narrow emission bands, large Stokes shifts, and high resistance to photobleaching. In this paper, we report a facile method for the preparation of highly fluorescent, water-soluble glutathione (GSH-coated NIR QDs for in vivo imaging. GSH-coated NIR QDs (GSH-QDs were prepared by surface modification of hydrophobic CdSeTe/CdS (core/shell QDs. The hydrophobic surface of the CdSeTe/CdS QDs was exchanged with GSH in tetrahydrofuran-water. The resulting GSH-QDs were monodisperse particles and stable in PBS (phosphate buffered saline, pH = 7.4. The GSH-QDs (800 nm emission were highly fluorescent in aqueous solutions (quantum yield = 22% in PBS buffer, and their hydrodynamic diameter was less than 10 nm, which is comparable to the size of proteins. The cellular uptake and viability for the GSH-QDs were examined using HeLa and HEK 293 cells. When the cells were incubated with aqueous solutions of the GSH-QDs (10 nM, the QDs were taken into the cells and distributed in the perinuclear region of both cells. After 12 hrs incubation of 4 nM of GSH-QDs, the viabilities of HeLa and HEK 293 cells were ca. 80 and 50%, respectively. As a biomedical utility of the GSH-QDs, in vivo NIRfluorescence imaging of a lymph node in a mouse is presented.

  7. Magnetic fluorescent lamp

    Science.gov (United States)

    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.

  8. Plasmonic fluorescent quantum dots

    OpenAIRE

    Jin, Yongdong; Gao, Xiaohu

    2009-01-01

    Combining multiple discrete components into a single multifunctional nanoparticle could be useful in a variety of applications. Retaining the unique optical and electrical properties of each component after nanoscale integration is, however, a long-standing problem1,2. It is particularly difficult when trying to combine fluorophores such as semiconductor quantum dots with plasmonic materials such as gold, because gold and other metals can quench the fluorescence3,4. So far, the combination of...

  9. Fluorescent nanodiamond for biomedicine

    International Nuclear Information System (INIS)

    NV centers in diamond have gained strong interest as a novel tool for quantum information processing, quantum computing and quantum photonics. These applications are based on fluorescent and spin properties of NV-centres. However, in some conditions NV- can lose an electron and turn to NV0. The occupation of NV0 and NV- charge states depend on the position of their ground states with respect to the Fermi level and the mechanism of the charge transfer. Interestingly, that the charge switch has important implications on applications of fluorescent nanodiamond (fND) to nano-biology and nano-medicine. fND can be used for bio-marking and bio-tracking but also for the monitoring of targeted delivery to the cells. In this presentation we review the current state-of-the art for using fND particles for fluorescent bio imaging in cells and discuss the charge transfer and its luminescence stability by using ultra high sensitive spectroscopy methods to study the NV0 and NV- state occupation. (author)

  10. Limitations of the Oriented Difference of Gaussian Filter in Special Cases of Brightness Perception Illusions.

    Science.gov (United States)

    Bakshi, Ashish; Roy, Sourya; Mallick, Arijit; Ghosh, Kuntal

    2016-03-01

    The Oriented Difference of Gaussian (ODOG) filter of Blakeslee and McCourt has been successfully employed to explain several brightness perception illusions which include illusions of both brightness-contrast type, for example, Simultaneous Brightness Contrast and Grating Induction and the brightness-assimilation type, for example, the White effect and the shifted White effect. Here, we demonstrate some limitations of the ODOG filter in predicting perceived brightness by comparing the ODOG responses to various stimuli (generated by varying two parameters, namely, test patch length and spatial frequency) with experimental observations of the same. PMID:26562859

  11. The properties of a large sample of low surface brightness galaxies from SDSS

    CERN Document Server

    Liang, Y C; Chen, X Y; Gao, D; Hammer, F; Liu, F S; Hu, J Y; Deng, L C; Zhang, B

    2009-01-01

    A large sample of low surface brightness (LSB) disk galaxies is selected from SDSS with B-band central surface brightness mu_0(B) from 22 to 24.5 mag arcsec^(-2). Some of their properties are studied, such as magnitudes, surface brightness, scalelengths, colors, metallicities, stellar populations, stellar masses and multiwavelength SEDs from UV to IR etc. These properties of LSB galaxies have been compared with those of the galaxies with higher surface brightnesses. Then we check the variations of these properties following surface brightness.

  12. Fluorescent-Antibody Targeting of Insulin-Like Growth Factor-1 Receptor Visualizes Metastatic Human Colon Cancer in Orthotopic Mouse Models

    OpenAIRE

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

    2016-01-01

    Fluorescent-antibody targeting of metastatic cancer has been demonstrated by our laboratory to enable tumor visualization and effective fluorescence-guided surgery. 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 metastatic colon cancer in orthotopic nude mouse models. IGF-1R antibody (clone 24–31) was conjugated with 550 nm, 650 nm or PEGylated 650 nm fluoropho...

  13. The new World Atlas of Artificial Sky Brightness

    Science.gov (United States)

    Falchi, Fabio; Cinzano, Pierantonio; Kyba, Christopher C. M.; Portnov, Boris A.

    2015-08-01

    I present the main steps toward the completion of the new World Atlas of Artificial Sky Brightness (WA II) and some results. The computational technique has been updated, in comparison to the first World Atlas, to take into account both sources and sites elevation. The elevation data are from USGS GTOPO30 global digital elevation model, with the same pixel size as the WA II maps. The upward emission function used to compute the Atlas is a three parameters function. The parameters can be constrained to the database of Earth based night sky brightness measurements. In this way we can use the better fitting upward function for the final map’s calibration. We maintained constant atmosphere parameters over the entire Earth, identical to those used for the first Atlas (Garstang atmospheric clarity coefficient k=1, equivalent to a vertical extinction at sea level of 0.33 magnitude in the V band). This was done in order to avoid introducing a local bias due to different conditions that may confound the light pollution propagation effects. The radiance data used are those from Visible Infrared Imaging Radiometer Suite (VIIRS) Day-Night Band (DNB) on board the Suomi NPP satellite. The use of this newly available radiance data allows for an increased real resolution, even while maintaining the same 30"x30" lat-lon pixel size. Anyway, a higher resolution is really appreciable only in the immediate proximity of sources of light pollution (e.g. inside a big city). The VIIRS DNB data used for the input data were chosen from the months ranging from May to September in order to avoid introducing bias from the variable snow coverage in mid to high northern latitudes. In the southern hemisphere this problem is far less pronounced. The WA II takes advantage of the now enormous database of Earth based sky brightness measurements obtained mainly with Sky Quality Meters, but also with CCD measurements.

  14. Bright source lasers and experiments at very high irradiance

    International Nuclear Information System (INIS)

    The Los Alamos Bright Source has been assembled to explore the effects of intense coherent ultraviolet radiation on matter. This ultra-high brightness excimer laser is used to study the response of atoms, ions, and plasmas to the unique conditions the laser can provide. Primary areas of interest include properties and behavior of highly energetic atomic species, studies of possible intense field-induced nuclear transitions, pumping for x-ray lasers, and incoherent x-ray sources. The project consists of two phases: Los Alamos Bright Source I (LABS I) that is now in operation and is producing experimental data at an intensity up to 7 x 1017 watts/cm2 with 25 mJ of radiation and LABS II that will deliver between .1 and 1 J at an intensity of 1018 to 1020 w/cm2. At these high intensities we observe collisionless excitations to the KeV level. The exact nature of the excitation process is not known and is itself part of the investigation. Because of the coherent nature of the pump and the very large fields obtainable, new regimes of optical excitation can be expected and examined. Work is underway with LABS I to produce highly ionized species and measure their spectral and other properties. This equipment has proven to be highly reliable in the last year and should afford the opportunity for many basic studies. LABS II with its increased pulse energy and intensity will support studies involving larger pump volume and higher excitation levels. It should serve as a test bed for studies of pumping schemes for x-ray lasers. 6 refs., 8 figs., 3 tabs

  15. Beyond pragmatism: defending the 'bright line' of birth.

    Science.gov (United States)

    Burin, Achas K

    2014-01-01

    It is usually accepted by ethicists that birth does not alter moral status. Rather, it is thought that the rule according full legal rights at birth is pragmatic. Pragmatic reasoning is vulnerable to competing practical concerns and stronger moral principles. This 'bright line' has therefore been criticised both by those who believe personhood begins before birth and those who believe it begins afterward. In particular, a recent article by Giubilini and Minerva puts forward both pragmatic and moral arguments in favour of permitting infanticide, and the New South Wales Court of Criminal Appeal has suggested there is a strong case for abandoning the bright line (R v Iby (2005) 63 NSWLR 278). If we desire to defend current legal doctrine against such criticism, a medical and philosophical basis for the law should be articulated. This article suggests such a medical and philosophical basis. It argues that both the multiplicity of biological changes occurring in the neonate at birth and the extrauterine context (the world) provide a justification for the distinction drawn at law between abortion and infanticide. With reference to Robert Nozick's 'experience machine' thought-experiment and elements of phenomenological philosophy, it advances two propositions to explain the status-changing nature of the neonate's emergence out of the womb. First, that expressing sentience in the world is essential for the attainment of personhood. Second, that having become a person, the harm in killing is disruption of this engagement with the world and the reduction from personhood to non-existence. This is the distinction between a neonate's death and the termination of a foetus, underscoring the qualitative difference between the two sides of the bright line drawn in law. PMID:24866181

  16. Ultra-high resolution and high-brightness AMOLED

    Science.gov (United States)

    Wacyk, Ihor; Ghosh, Amal; Prache, Olivier; Draper, Russ; Fellowes, Dave

    2012-06-01

    As part of its continuing effort to improve both the resolution and optical performance of AMOLED microdisplays, eMagin has recently developed an SXGA (1280×3×1024) microdisplay under a US Army RDECOM CERDEC NVESD contract that combines the world's smallest OLED pixel pitch with an ultra-high brightness green OLED emitter. This development is aimed at next-generation HMD systems with "see-through" and daylight imaging requirements. The OLED pixel array is built on a 0.18-micron CMOS backplane and contains over 4 million individually addressable pixels with a pixel pitch of 2.7 × 8.1 microns, resulting in an active area of 0.52 inches diagonal. Using both spatial and temporal enhancement, the display can provide over 10-bits of gray-level control for high dynamic range applications. The new pixel design also enables the future implementation of a full-color QSXGA (2560 × RGB × 2048) microdisplay in an active area of only 1.05 inch diagonal. A low-power serialized low-voltage-differential-signaling (LVDS) interface is integrated into the display for use as a remote video link for tethered systems. The new SXGA backplane has been combined with the high-brightness green OLED device developed by eMagin under an NVESD contract. This OLED device has produced an output brightness of more than 8000fL with all pixels on; lifetime measurements are currently underway and will presented at the meeting. This paper will describe the operational features and first optical and electrical test results of the new SXGA demonstrator microdisplay.

  17. Magneto-optical control of bright atomic solitons

    OpenAIRE

    Potting, S.; Zobay, O.; Meystre, P.; Wright, E. M.

    2000-01-01

    In previous work we showed that bright atomic solitons can arise in spinor Bose-Einstein condensates in the form of gap solitons even for repulsive many-body interactions. Here we further explore the properties of atomic gap solitons and show that their internal structure can be used to both excite them and control their center-of-mass motion using applied laser and magnetic fields. As an illustration we demonstrate a nonlinear atom-optical Mach-Zehnder interferometer based on gap solitons.

  18. Time series analysis of bright galactic X-ray sources

    DEFF Research Database (Denmark)

    Priedhorsky, W. C.; Brandt, Søren; Lund, Niels

    1995-01-01

    We analyze 70 to 110 day data sets from eight bright galactic X-ray binaries observed by WATCH/Eureca, in search of periodic variations. We obtain new epochs for the orbital variation of Cyg X-3 and 4U 1700-37, and confirmation of a dip in Cyg X-1 at superior conjunction of the X-ray star. No evi...... evidence for variation at known and candidate periods is seen for Sco X-1, Cyg X-2, and GX 17+2. We set upper limits for variation at other frequencies in those three sources, GX 5-1, and GRS 1915+105....

  19. FACT — LONGTERM MONITORING OF BRIGHT TeV BLAZARS

    Directory of Open Access Journals (Sweden)

    Katja Meier

    2014-06-01

    Full Text Available The First G-APD Cherenkov Telescope (FACT, located on the Canary Island of La Palma, has been taking data since October 2011. FACT has been optimized for longterm monitoring of bright TeV blazars, to study their variability time scales and flare probability. G-APD photo-sensors allow for observations even under strong moonlight conditions, and the telescope can be operated remotely. The monitoring strategy of FACT is discussed and preliminary results of the flare of Mrk501 in June 2012 are shown.

  20. Formation of Solar Calcium H and K Bright Grains

    Science.gov (United States)

    Carlsson, Mats; Stein, Robert F.

    1997-05-01

    We have simulated the generation of Ca II H2V bright grains by acoustic shocks. We employ a one-dimensional, non-LTE radiation-hydrodynamic code, with six-level model atoms for hydrogen and singly ionized calcium. We drive acoustic waves through a stratified radiative equilibrium atmosphere by a piston, whose velocity is chosen to match the Doppler shift observed in the Fe I 396.68 nm line in the H line wing, formed at about 260 km above τ500 = 1. The simulations closely match the observed behavior of Ca II H2V bright grains down to the level of individual grains. The bright grains are produced by shocks near 1 Mm above τ500 = 1. Shocks in the mid-chromosphere produce a large source function (and therefore high emissivity) because the density is high enough for collisions to couple the Ca II populations to the local conditions. The asymmetry of the line profile is due to velocity gradients near 1 Mm. Material motion Doppler-shifts the frequency at which atoms emit and absorb photons, so the maximum opacity is located at--and the absorption profile is symmetric about--the local fluid velocity, which is shifted to the blue behind shocks. The optical depth depends upon the velocity structure higher up. Shocks propagate generally into downflowing material, so there is little matter above to absorb the Doppler-shifted radiation. The corresponding red peak is absent because of small opacity at the source function maximum and large optical depth due to overlying material. The bright grains are produced primarily by waves from the photosphere that are slightly above the acoustic cutoff frequency. The precise time and strength of a grain depend upon the interference between these waves near the acoustic cutoff frequency and higher frequency waves. When waves near the acoustic cutoff frequency are weak, then higher frequency waves may produce grains. The ``5 minute'' trapped p-mode oscillations are not the source of the grains, although they can slightly modify the

  1. Generation of bright soliton through the interaction of black solitons

    CERN Document Server

    Losano, L; Bazeia, D

    2001-01-01

    We report on the possibility of having two black solitons interacting inside a silica fiber that presents normal group-velocity dispersion, to generate a pair of solitons, a vector soliton of the black-bright type. The model obeys a pair of coupled nonlinear Schr\\"odinger equations, that follows in accordance with a Ginzburg-Landau equation describing the anisotropic XY model. We solve the coupled equations using a trial-orbit method, which plays a significant role when the Schr\\"odinger equations are reduced to first order differential equations.

  2. Matter-wave bright solitons in effective bichromatic lattice potentials

    Indian Academy of Sciences (India)

    Golam Ali Sekh

    2013-08-01

    Matter-wave bright solitons in bichromatic lattice potentials are considered and their dynamics for different lattice environments are studied. Bichromatic potentials are created from superpositions of (i) two linear optical lattices and (ii) a linear and a nonlinear optical lattice. Effective potentials are found for the solitons in both bichromatic lattices and a comparative study is done on the dynamics of solitons with respect to the effective potentials. The effects of dispersion on solitons in bichromatic lattices are studied and it is found that the dispersive spreading can be minimized by appropriate combinations of lattice and interaction parameters. Stability of nondispersive matter-wave solitons is checked from phase portrait analysis.

  3. Development of pierce type high-brightness electron gun

    International Nuclear Information System (INIS)

    A Pierce type electron gun has been developed. High voltage of 200kV DC is effective for the purpose of high brightness. A compact insulation gas tank of 600mmx600mmφ, and a very simple structure of high voltage feeding is realized by insulation designing using an electric field analysis. At the test bench experiments, high voltage of 200kV was achieved, which justifies our design. After a measurement of electron beam characteristics, the gun has been installed into linac system and operated stably. (author)

  4. Continuous variable quantum communication with bright entangled optical beams

    Institute of Scientific and Technical Information of China (English)

    XIE Chang-de; ZHANG Jing; PAN Qing; JIA Xiao-jun; PENG Kun-chi

    2006-01-01

    In this paper,we briefly introduce the basic concepts and protocols of continuous variable quantum communication,and then summarize the experimental researches accomplished by our group in this field.The main features of quantum communication systems used in our experiments are:(1) The bright entangled optical beams with the anticorrelated amplitude quadratures and the correlated phase quadratures that serve as the entanglement resources and (2) The Bell-state direct detection systems are utilized in the measurements of quantum entanglement and transmitted signals instead of the usually balanced homodyne detectors.

  5. The brightness and spatial distributions of terrestrial radio sources

    OpenAIRE

    Offringa, A. R.; et al, .; Leeuwen, van; Wise, M.

    2013-01-01

    Faint undetected sources of radio-frequency interference (RFI) might become visible in long radio observations when they are consistently present over time. Thereby, they might obstruct the detection of the weak astronomical signals of interest. This issue is especially important for Epoch of Reionization (EoR) projects that try to detect the faint redshifted H i signals from the time of the earliest structures in the Universe. We explore the RFI situation at 30-163 MHz by studying brightness...

  6. Enhanced brightness from all solution processable biopolymer LED

    Science.gov (United States)

    Pradeep, C.; Namboothiry, M. A. G.; Vallabhan, C. P. G.; Radhakrishnan, P.; Nampoori, V. P. N.

    2015-08-01

    Biopolymer light emitting diodes were fabricated by using all solution processable polymers incorporating biomaterials such as deoxyribonucleic acid lipid complex as an electron blocking layer. Light emission is from a blend of fluorene based copolymers. The devices with electron blocking layer exhibited higher brightness and luminous efficiency. The increased luminance of the multilayer polymer LED is attributed to the contribution from DNA:CTMA as electron blocking layer and PFN, a derivative of polyfluorene, as electron injection layer. Our results show four fold increase in luminance values when DNA is used as electron blocking layer.

  7. The UV-bright Quasar Survey (UVQS): DR1

    CERN Document Server

    Monroe, TalaWanda R; Tejos, N; Worseck, G; Hennawi, Joseph F; Schmidt, Tobias; Tumlinson, Jason; Shen, Yue

    2016-01-01

    We present the first data release (DR1) from our UV-bright Quasar Survey (UVQS) for new $z \\sim 1$ active galactic nuclei (AGN) across the sky. Using simple GALEX UV and WISE near-IR color selection criteria, we generated a list of 1450 primary candidates with $FUV 0.5$. Including a small set of observed secondary candidates, we report the discovery of 217 AGN with $FUV < 18$ mag that had no previously reported spectroscopic redshift. These are excellent potential targets for UV spectroscopy before the end of the {\\it Hubble Space Telescope} mission. The main data products are publicly released through the Mikulski Archive for Space Telescopes.

  8. The Spectral Energy Distribution of Fermi bright blazars

    CERN Document Server

    Abdo, A A; Ajello, M; Axelsson, M; Baldini, L; Ballet, J; Barbiellini, G; Bastieri, D; Baughman, B M; Bechtol, K; Bellazzini, R; Berenji, B; Blandford, R D; Bloom, E D; Bonamente, E; Borgland, A; Bregeon, J; Brez, A; Brigida, M; Bruel, P; Burnett, T H; Buson, S; Caliandro, G A; Cameron, R A; Caraveo, P A; Casandjian, J M; Cavazzuti, E; Cecchi, C; Celik, O; Charles, E; Chaty, S; Chekhtman, A; Chiang, J; Ciprini, S; Claus, R; Cohen-Tanugi, J; Colafrancesco, S; Cominsky, L R; Conrad, J; Costamante, L; Cutini, S; Dermer, C D; de Angelis, A; de Palma, F; Digel, S W; Silva, E do Couto e; Drell, P S; Dubois, R; Dumora, D; Farnier, C; Favuzzi, C; Fegan, S J; Focke, W B; Fortin, P; Frailis, M; Fuhrmann, L; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Germani, S; Giebels, B; Giglietto, N; Giommi, P; Giordano, F; Glanzman, T; Godfrey, G; Grenier, I A; Grove, J E; Guillemot, L; Guiriec, S; Hadasch, D; Hanabata, Y; Harding, A K; Hayashida, M; Hays, E; Healey, S E; Horan, D; Hughes, R E; Itoh, R; Jackson, M S; Johannesson, G; Johnson, A S; Johnson, W N; Kadler, M; Kamae, T; Katagiri, H; Kataoka, J; Kawai, N; Kerr, M; Knodlseder, J; Kocian, M L; Kuss, M; Lande, J; Latronico, L; Longo, F; Loparco, F; Lott, B; Lovellette, M N; Lubrano, P; Madejski, G M; Makeev, A; Max-Moerbeck, W; Mazziotta, M N; McConville, W; McEnery, J E; Meurer, C; Michelson, P F

    2009-01-01

    (Abridged) We have conducted a detailed investigation of the broad-band spectral properties of the \\gamma-ray selected blazars of the Fermi LAT Bright AGN Sample (LBAS). By combining our accurately estimated Fermi gamma-ray spectra with Swift, radio, infra-red, optical and other hard X-ray/gamma-ray data, collected within three months of the LBAS data taking period, we were able to assemble high-quality and quasi-simultaneous Spectral Energy Distributions (SED) for 48 LBAS blazars.The SED of these gamma-ray sources is similar to that of blazars discovered at other wavelengths, clearly showing, in the usual Log $\

  9. X-ray observations of the bright quasar survey

    International Nuclear Information System (INIS)

    Using the Einstein Observatory, X-ray observations of about 80 percent of the quasars in the Bright Quasar Survey located outside the declination range defined by 30 and 60 deg. X-ray emission has been detected above the 3-sigma level for 57 out of 66 quasars observed. This paper describes observations and data reduction and provides a summary of the more detailed analyses and discussion contained in the two accompanying papers (Schmidt and Green 1986, Avni and Tananbaum 1986). 22 references

  10. A Complete Sample of Long Bright Swift GRBs

    CERN Document Server

    Salvaterra, R; Covino, S; D'Avanzo, P; Ghirlanda, G; Ghisellini, G; Melandi, A; Tagliaferri, G; Nava, L; Vergani, S

    2013-01-01

    Starting from the Swift sample we define a complete sub-sample of 58 bright long Gamma Ray Bursts (GRB), 55 of them (95%) with a redshift determination, in order to characterize their properties. Our sample (BAT6) allows us to study the properties of the long GRB population and their evolution with cosmic time. We focus in particular on the GRB luminosity function, on the spectral-energy correlations of their prompt emission, on the nature of dark bursts, on possible correlations between the prompt and the X-ray afterglow properties, and on the dust extinction.

  11. A Complete Sample of Long Bright Swift GRBs

    OpenAIRE

    Salvaterra, R.; Campana, S.; S. Covino(INAF - Oss. Astronomico di Brera); D'Avanzo, P.; Ghirlanda, G.; Ghisellini, G.; Melandi, A.; Tagliaferri, G.; Nava, L.; Vergani, S.

    2013-01-01

    Starting from the Swift sample we define a complete sub-sample of 58 bright long Gamma Ray Bursts (GRB), 55 of them (95%) with a redshift determination, in order to characterize their properties. Our sample (BAT6) allows us to study the properties of the long GRB population and their evolution with cosmic time. We focus in particular on the GRB luminosity function, on the spectral-energy correlations of their prompt emission, on the nature of dark bursts, on possible correlations between the ...

  12. Three low surface brightness dwarfs discovered around NGC 4631

    OpenAIRE

    Karachentsev, Igor D.; Bautzmann, Dirk; Neyer, Fabian; Polzl, Robert; Riepe, Peter; Zilch, Thorsten; Mattern, Bruno

    2014-01-01

    We report the discovery of three low surface brightness companions to the spiral galaxy NGC 4631, made with small amateur telescopes. Assuming their distances to be 7.4 Mpc, the same as that of NGC 4631, the absolute magnitudes and linear diameters of the dwarfs are ranged within [-12.5, -9.6] mag and [4.7 - 1.3] kpc, respectively. These new three dwarfs, together with the discovered by us diffuse structure called "bridge", look like parts of a tidal filament directed towards NGC 4656 at tota...

  13. Completion of the brightness upgrade of the ALS

    International Nuclear Information System (INIS)

    The Advanced Light Source (ALS) at Berkeley Lab remains one of the brightest sources for soft x-rays worldwide. A multiyear upgrade of the ALS is underway, which includes new and replacement x-ray beamlines, a replacement of many of the original insertion devices and many upgrades to the accelerator. The accelerator upgrade that affects the ALS performance most directly is the ALS brightness upgrade [1], which reduces the horizontal emittance from 6.3 to 2.0 nm (2.5 nm effective). Magnets for this upgrade were installed in late 2012 and early 2013 followed by user operation with the reduced emittance.

  14. Spectral Index Changes with Brightness for -Ray Loud Blazars

    Indian Academy of Sciences (India)

    J. H. Yang; R. S. Yang; J. J. Nie; J. H. Fan

    2014-09-01

    Based on Fermi 1FGL and 2FGL data, a sample of 572 -ray loud blazars are selected, in which each source has both -ray flux and spectral index in 1FGL and 2FGL, respectively. Theoretic relation of spectral index changes depending on -ray brightness is obtained. The correlations between the ratio of -ray flux densities and the differences of the -ray spectral indices are discussed for the three subclasses of HBL, LBL and FSRQs. Results show that the ratio is related with the differences for the three subclasses. It is consistent with the theoretical result and it indicates that the spectrum becomes flat as the source brightens in the -ray band.

  15. Generation of high brightness ion beam from insulated anode PED

    International Nuclear Information System (INIS)

    Generation and focusing of a high density ion beam with high brightness from a organic center part of anode of a PED was reported previously. Mass, charge and energy distribution of this beam were analyzed. Three kind of anode were tried. Many highly ionized medium mass ions (up to C4+, O6+) accelarated to several times of voltage difference between anode and cathode were observed. In the case of all insulator anode the current carried by the medium mass ions is about half of that carried by protons. (author)

  16. Preparation of Reactive Bright Blue Rare Earth Dyestuffs and Their Spectra Properties

    Institute of Scientific and Technical Information of China (English)

    Liu Xiaozhen; Sang Wenbin

    2004-01-01

    Reactive bright blue rare earth dyestuffs were prepared by using reactive bright blue and lanthanum oxide,praseodymium oxide, neodymium oxide, samarium oxide, europium oxide, gadolinium oxide, dysprosium oxide, erbium oxide, lutetium oxide, yttrium oxide respectively for dyeing silk cloth.The degree of dyeing of reactive bright blue praseodymium and the degree of fixation of reactive bright blue gadolinium are the biggest, and 22.9% and 7 %are increased with that of reactive bright blue respectively.The spectra of reactive bright blue rare earth and reactive bright blue were studied by UV-VIS.In 200.00 ~ 800.00 nm, reactive bright blue has four absorption peaks, reactive bright blue rare earth has three absorption peaks; in 420.00 ~ 760.00 nm, reactive bright blue has two absorption peaks at 661.50 nm and 625.50 nm, respectively, and λmax is 661.50 nm; reactive bright blue rare earth has one absorption peak at 620.50, 618.00, 622.00, 623.00, 622.50, 619.50, 619.00, 621.00, 624.00, 620.00 nm adding La3+ ,Pr3+, Nd3+, Sm3+, Eu3+, Gd3+, Dy3+, Er3+, Lu3+, Y3+respectively.

  17. Low surface brightness galaxies in the Fornax Cluster: automated galaxy surface photometry

    International Nuclear Information System (INIS)

    A sample is presented of low surface brightness galaxies (with extrapolated central surface brightness fainter than 22.0 Bμ) in the Fornax Cluster region which has been measured by the APM machine. Photometric parameters, namely profile shape, scale length, central brightness and total magnitude, are derived for the sample galaxies and correlations between the parameters of low surface brightness dwarf galaxies are discussed, with particular reference to the selection limits. Contrary to previous authors we find no evidence for a luminosity-surface brightness correlation in the sense of lower surface brightness galaxies having lower luminosities and scale sizes. In fact, the present data suggest that it is the galaxies with the largest scale lengths which are more likely to be of very low surface brightness. In addition, the larger scale length galaxies occur preferentially towards the centre of the Cluster. (author)

  18. Circularly permuted monomeric red fluorescent proteins with new termini in the beta-sheet.

    Science.gov (United States)

    Carlson, Haley J; Cotton, Darrel W; Campbell, Robert E

    2010-08-01

    Circularly permuted fluorescent proteins (FPs) have a growing number of uses in live cell fluorescence biosensing applications. Most notably, they enable the construction of single fluorescent protein-based biosensors for Ca(2+) and other analytes of interest. Circularly permuted FPs are also of great utility in the optimization of fluorescence resonance energy transfer (FRET)-based biosensors by providing a means for varying the critical dipole-dipole orientation. We have previously reported on our efforts to create circularly permuted variants of a monomeric red FP (RFP) known as mCherry. In our previous work, we had identified six distinct locations within mCherry that tolerated the insertion of a short peptide sequence. Creation of circularly permuted variants with new termini at the locations corresponding to the sites of insertion led to the discovery of three permuted variants that retained no more than 18% of the brightness of mCherry. We now report the extensive directed evolution of the variant with new termini at position 193 of the protein sequence for improved fluorescent brightness. The resulting variant, known as cp193g7, has 61% of the intrinsic brightness of mCherry and was found to be highly tolerant of circular permutation at other locations within the sequence. We have exploited this property to engineer an expanded series of circularly permuted variants with new termini located along the length of the 10th beta-strand of mCherry. These new variants may ultimately prove useful for the creation of single FP-based Ca(2+) biosensors. PMID:20521333

  19. Small fluorescence-activating and absorption-shifting tag for tunable protein imaging in vivo.

    Science.gov (United States)

    Plamont, Marie-Aude; Billon-Denis, Emmanuelle; Maurin, Sylvie; Gauron, Carole; Pimenta, Frederico M; Specht, Christian G; Shi, Jian; Quérard, Jérôme; Pan, Buyan; Rossignol, Julien; Morellet, Nelly; Volovitch, Michel; Lescop, Ewen; Chen, Yong; Triller, Antoine; Vriz, Sophie; Le Saux, Thomas; Jullien, Ludovic; Gautier, Arnaud

    2016-01-19

    This paper presents Yellow Fluorescence-Activating and absorption-Shifting Tag (Y-FAST), a small monomeric protein tag, half as large as the green fluorescent protein, enabling fluorescent labeling of proteins in a reversible and specific manner through the reversible binding and activation of a cell-permeant and nontoxic fluorogenic ligand (a so-called fluorogen). A unique fluorogen activation mechanism based on two spectroscopic changes, increase of fluorescence quantum yield and absorption red shift, provides high labeling selectivity. Y-FAST was engineered from the 14-kDa photoactive yellow protein by directed evolution using yeast display and fluorescence-activated cell sorting. Y-FAST is as bright as common fluorescent proteins, exhibits good photostability, and allows the efficient labeling of proteins in various organelles and hosts. Upon fluorogen binding, fluorescence appears instantaneously, allowing monitoring of rapid processes in near real time. Y-FAST distinguishes itself from other tagging systems because the fluorogen binding is highly dynamic and fully reversible, which enables rapid labeling and unlabeling of proteins by addition and withdrawal of the fluorogen, opening new exciting prospects for the development of multiplexing imaging protocols based on sequential labeling. PMID:26711992

  20. Fluorescent Cy5 silica nanoparticles for cancer cell imaging

    Science.gov (United States)

    O'Connell, Claire; Nooney, Robert I.; Glynn, MacDara; Ducree, Jens; McDonagh, Colette

    2015-08-01

    Cancer is a leading cause of death worldwide, with metastasis responsible for the majority of cancer-related deaths. Circulating tumour cells (CTCs) play a central role in metastasis. Fluorescent silica particles (NPs), of diameter ~50 nm which contain a large concentration of Cy5 dye molecules and are extremely bright, have been developed to detect these rare CTCs. Due to this brightness, the particles have superior performance compared to single Cy5 dye molecule labels, for detecting cancer cells. Fluorescence measurements show that the NPs are almost 100 times brighter than the free dye. They do not photo bleach as readily and, due to the biocompatible silica surface, they can be chemically modified, layer-by-layer, in order to bind to cells. The choice of these chemical layers, in particular the NP to antibody linker, along with the incubation period and type of media used in the incubation, has a strong influence on the specific binding abilities of the NPs. In this work, NPs have been shown to selectively bind to the MCF-7 cell line by targeting epithelial cellular adhesion molecule (EpCAM) present on the MCF-7 cell membrane by conjugating anti-EpCAM antibody to the NP surface. Results have shown a high signal to noise ratio for this cell line in comparison to a HeLa control line. NP attachment to cells was verified qualitatively with the use of fluorescence microscopy and quantitatively using image analysis methods. Once the system has been optimised, other dyes will be doped into the silica NPs and their use in multiplexing will be investigated.

  1. Transgenic nude mouse with ubiquitous green fluorescent protein expression as a host for human tumors.

    Science.gov (United States)

    Yang, Meng; Reynoso, Jose; Jiang, Ping; Li, Lingna; Moossa, Abdool R; Hoffman, Robert M

    2004-12-01

    We report here the development of the transgenic green fluorescent protein (GFP) nude mouse with ubiquitous GFP expression. The GFP nude mouse was obtained by crossing nontransgenic nude mice with the transgenic C57/B6 mouse in which the beta-actin promoter drives GFP expression in essentially all tissues. In crosses between nu/nu GFP male mice and nu/+ GFP female mice, the embryos fluoresced green. Approximately 50% of the offspring of these mice were GFP nude mice. Newborn mice and adult mice fluoresced very bright green and could be detected with a simple blue-light-emitting diode flashlight with a central peak of 470 nm and a bypass emission filter. In the adult mice, the organs all brightly expressed GFP, including the heart, lungs, spleen, pancreas, esophagus, stomach, and duodenum. The following systems were dissected out and shown to have brilliant GFP fluorescence: the entire digestive system from tongue to anus; the male and female reproductive systems; brain and spinal cord; and the circulatory system, including the heart and major arteries and veins. The skinned skeleton highly expressed GFP. Pancreatic islets showed GFP fluorescence. The spleen cells were also GFP positive. Red fluorescent protein (RFP)-expressing human cancer cell lines, including PC-3-RFP prostate cancer, HCT-116-RFP colon cancer, MDA-MB-435-RFP breast cancer, and HT1080-RFP fibrosarcoma were transplanted to the transgenic GFP nude mice. All of these human tumors grew extensively in the transgenic GFP nude mouse. Dual-color fluorescence imaging enabled visualization of human tumor-host interaction by whole-body imaging and at the cellular level in fresh and frozen tissues. The GFP mouse model should greatly expand our knowledge of human tumor-host interaction. PMID:15574773

  2. Statistical Properties of Bright Galaxies in the SDSS Photometric System

    CERN Document Server

    Shimasaku, K; Doi, M; Hamabe, M; Ichikawa, T; Okamura, S; Sekiguchi, M; Yasuda, N

    2001-01-01

    We investigate the photometric properties of 456 bright galaxies using imaging data recorded during the commissioning phase of the Sloan Digital Sky Survey (SDSS). Morphological classification is carried out by correlating results of several human classifiers. Our purpose is to examine the statistical properties of color indices, scale lengths, and concentration indices as functions of morphology for the SDSS photometric system. We find that $u'-g'$, $g'-r'$, and $r'-i'$ colors of SDSS galaxies match well with those expected from the synthetic calculation of spectroscopic energy distribution of template galaxies and with those transformed from $UBVR_CI_C$ color data of nearby galaxies. The agreement is somewhat poor, however, for $i'-z'$ color band with a discrepancy of $0.1-0.2$ mag. With the aid of the relation between surface brightness and radius obtained by Kent (1985), we estimate the averages of the effective radius of early type galaxies and the scale length of exponential disks both to be 2.6 kpc for...

  3. Surface Brightness Profiles of Dwarf Galaxies: I. Profiles and Statistics

    CERN Document Server

    Herrmann, Kimberly A; Elmegreen, Bruce G

    2013-01-01

    Radial surface brightness profiles of spiral galaxies are classified into three types: (I) single exponential, or the light falls off with one exponential to a break before falling off (II) more steeply, or (III) less steeply. Profile breaks are also found in dwarf disks, but some dwarf Type IIs are flat or increasing out to a break before falling off. Here we re-examine the stellar disk profiles of 141 dwarfs: 96 dwarf irregulars (dIms), 26 Blue Compact Dwarfs (BCDs), and 19 Magellanic-type spirals (Sms). We fit single, double, or even triple exponential profiles in up to 11 passbands: GALEX FUV and NUV, ground-based UBV JHK and H{\\alpha}, and Spitzer 3.6 and 4.5 {\\mu}m. We find that more luminous galaxies have brighter centers, larger inner and outer scale lengths, and break at larger radii; dwarf trends with M_B extend to spirals. However, the V-band break surface brightness is independent of break type, M_B, and Hubble type. Dwarf Type II and III profiles fall off similarly beyond the breaks but have diff...

  4. Dynamic properties of bright points in an active region

    CERN Document Server

    Keys, Peter H; Jess, David B; Mackay, Duncan H; Keenan, Francis P

    2014-01-01

    Context. Bright points (BPs) are small-scale, magnetic features ubiquitous across the solar surface. Previously, we have observed and noted their properties for quiet Sun regions. Here, we determine the dynamic properties of BPs using simultaneous quiet Sun and active region data. Methods. High spatial and temporal resolution G-band observations of active region AR11372 were obtained with the Rapid Oscillations in the Solar Atmosphere instrument at the Dunn Solar Telescope. Three subfields of varying polarity and magnetic flux density were selected with the aid of magnetograms obtained from the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory. Bright points within these subfields were subsequently tracked and analysed. Results. It is found that BPs within active regions display attenuated velocity distributions with an average horizontal velocity of ~0.6 km/s, compared to the quiet region which had an average velocity of 0.9 km/s. Active region BPs are also ~21% larger than quiet regio...

  5. Bright light treatment of depression for older adults [ISRCTN55452501

    Directory of Open Access Journals (Sweden)

    Knickerbocker Nancy C

    2005-11-01

    Full Text Available Abstract Background The incidence of insomnia and depression in the elder population is significant. It is hoped that use of light treatment for this group could provide safe, economic, and effective rapid recovery. Methods In this home-based trial we treated depressed elderly subjects with bright white (8,500 Lux and dim red ( Results Eighty-one volunteers, between 60 and 79 years old, completed the study. Both treatment and placebo groups experienced mood improvement. Average GDS scores improved 5 points, the Hamilton Depression Rating Scale (HDRS 17 scores (extracted from the self-rated SIGH-SAD-SR improved 6 points. There were no significant treatment effects or time-by-treatment interactions. No significant adverse reactions were observed in either treatment group. The assays of urine and saliva showed no significant differences between the treatment and placebo groups. The healthy control group was active earlier and slept earlier but received less light than the depressed group at baseline. Conclusion Antidepressant response to bright light treatment in this age group was not statistically superior to placebo. Both treatment and placebo groups experienced a clinically significant overall improvement of 16%.

  6. The ALS -- A high-brightness XUV synchrotron radiation source

    International Nuclear Information System (INIS)

    The Advanced Light Source (ALS) at the Lawrence Berkeley Laboratory is scheduled to be operational in the spring of 1993 as a US Department of Energy national user facility. The ALS will be a next-generation source of soft x-ray and ultraviolet (XUV) synchrotron radiation. Undulators will provide high-brightness radiation oat photon energies from below 10 eV to above 2 keV; wiggler and bend-magnet radiation will extend the spectral coverage with high fluxes approaching 20 keV. The ALS will support an extensive research program in which XUV radiation is used to study matter in all its varied gaseous, liquid, and solid forms. the high brightness will open new areas of research from the materials sciences, such as spatially resolved spectroscopy, to the life sciences, such as x-ray microscopy with element-specific sensitivity. Experimental facilities (insertion devices, beamlines, and end stations) will be developed and operated by participating research teams working with the ALS staff. 6 refs., 2 figs., 2 tabs

  7. The brightness and spatial distributions of terrestrial radio sources

    Science.gov (United States)

    Offringa, A. R.; de Bruyn, A. G.; Zaroubi, S.; Koopmans, L. V. E.; Wijnholds, S. J.; Abdalla, F. B.; Brouw, W. N.; Ciardi, B.; Iliev, I. T.; Harker, G. J. A.; Mellema, G.; Bernardi, G.; Zarka, P.; Ghosh, A.; Alexov, A.; Anderson, J.; Asgekar, A.; Avruch, I. M.; Beck, R.; Bell, M. E.; Bell, M. R.; Bentum, M. J.; Best, P.; Bîrzan, L.; Breitling, F.; Broderick, J.; Brüggen, M.; Butcher, H. R.; de Gasperin, F.; de Geus, E.; de Vos, M.; Duscha, S.; Eislöffel, J.; Fallows, R. A.; Ferrari, C.; Frieswijk, W.; Garrett, M. A.; Grießmeier, J.; Hassall, T. E.; Horneffer, A.; Iacobelli, M.; Juette, E.; Karastergiou, A.; Klijn, W.; Kondratiev, V. I.; Kuniyoshi, M.; Kuper, G.; van Leeuwen, J.; Loose, M.; Maat, P.; Macario, G.; Mann, G.; McKean, J. P.; Meulman, H.; Norden, M. J.; Orru, E.; Paas, H.; Pandey-Pommier, M.; Pizzo, R.; Polatidis, A. G.; Rafferty, D.; Reich, W.; van Nieuwpoort, R.; Röttgering, H.; Scaife, A. M. M.; Sluman, J.; Smirnov, O.; Sobey, C.; Tagger, M.; Tang, Y.; Tasse, C.; Veen, S. ter; Toribio, C.; Vermeulen, R.; Vocks, C.; van Weeren, R. J.; Wise, M. W.; Wucknitz, O.

    2013-10-01

    Faint undetected sources of radio-frequency interference (RFI) might become visible in long radio observations when they are consistently present over time. Thereby, they might obstruct the detection of the weak astronomical signals of interest. This issue is especially important for Epoch of Reionization (EoR) projects that try to detect the faint redshifted H I signals from the time of the earliest structures in the Universe. We explore the RFI situation at 30-163 MHz by studying brightness histograms of visibility data observed with Low-Frequency Array (LOFAR), similar to radio-source-count analyses that are used in cosmology. An empirical RFI distribution model is derived that allows the simulation of RFI in radio observations. The brightness histograms show an RFI distribution that follows a power-law distribution with an estimated exponent around -1.5. With several assumptions, this can be explained with a uniform distribution of terrestrial radio sources whose radiation follows existing propagation models. Extrapolation of the power law implies that the current LOFAR EoR observations should be severely RFI limited if the strength of RFI sources remains strong after time integration. This is in contrast with actual observations, which almost reach the thermal noise and are thought not to be limited by RFI. Therefore, we conclude that it is unlikely that there are undetected RFI sources that will become visible in long observations. Consequently, there is no indication that RFI will prevent an EoR detection with LOFAR.

  8. Multiwavelength investigations of co-evolution of bright custer galaxies

    CERN Document Server

    Hashimoto, Yasuhiro; Boehringer, Hans

    2014-01-01

    We report a systematic multi-wavelength investigation of environments of the brightest cluster galaxies (BCGs), using the X-ray data from the Chandra archive, and optical images taken with 34'x 27' field-of-view Subaru Suprime-Cam. Our goal is to help understand the relationship between the BCGs and their host clusters, and between the BCGs and other galaxies, to eventually address a question of the formation and co-evolution of BCGs and the clusters. Our results include: 1) Morphological variety of BCGs, or the second or the third brightest galaxy (BCG2, BCG3), is comparable to that of other bright red sequence galaxies, suggesting that we have a continuous variation of morphology between BCGs, BCG2, and BCG3, rather than a sharp separation between the BCG and the rest of the bright galaxies. 2) The offset of the BCG position relative to the cluster centre is correlated to the degree of concentration of cluster X-ray morphology (Spearman rho = -0.79), consistent with an interpretation that BCGs tend to be of...

  9. Bright low mass eclipsing binary candidates observed by STEREO

    CERN Document Server

    Wraight, K T; White, Glenn J; Norton, A J; Bewsher, D

    2012-01-01

    Observations from the Heliospheric Imagers (HI-1) on both the STEREO spacecraft have been analysed to search for bright low mass eclipsing binaries (EBs) and potential brown dwarf transits and to determine the radii of the companions. A total of 9 EB candidates have been found, ranging in brightness from V=6.59 mag to V=11.3 mag, where the radius of the companion appears to be less than 0.4 Rsol, with a diverse range of host temperatures, from 4074 K to 6925 K. Both components of one candidate, BD-07 3648, appear to be less than 0.4 Rsol and this represents a particularly interesting system for further study. The shapes of the eclipses in some cases are not clear enough to be certain they are total and the corresponding radii found should therefore be considered as lower limits. The EBs reported in this paper have either been newly found by the present analysis, or previously reported to be eclipsing by our earlier STEREO/HI-1 results. One of the new objects has subsequently been confirmed using archival Supe...

  10. Ultra Low Surface Brightness Imaging with the Dragonfly Telephoto Array

    CERN Document Server

    Abraham, Roberto G

    2014-01-01

    We describe the Dragonfly Telephoto Array, a robotic imaging system optimized for the detection of extended ultra low surface brightness structures. The array consists of eight Canon 400mm f/2.8 telephoto lenses coupled to eight science-grade commercial CCD cameras. The lenses are mounted on a common framework and are co-aligned to image simultaneously the same position on the sky. The system provides an imaging capability equivalent to a 0.4m aperture f/1.0 refractor with a 2.6 deg X 1.9 deg field of view. The system has no obstructions in the light path, optimized baffling, and internal optical surfaces coated with a new generation of anti-reflection coatings based on sub-wavelength nanostructures. As a result, the array's point spread function has a factor of ~10 less scattered light at large radii than well-baffled reflecting telescopes. The Dragonfly Telephoto Array is capable of imaging extended structures to surface brightness levels below 30 mag/arcsec^2 in 10h integrations (without binning or foregro...

  11. An X-ray survey of variable radio bright quasars

    International Nuclear Information System (INIS)

    A sample consisting primarily of radio bright quasars was observed in X-rays with the Einstein Observatory for times ranging from 1500 to 5000 seconds. Detected sources had luminosities ranging from 0.2 to 41.0 x 10 to the 45th power ergs/sec in the 0.5 to 4.5 keV band. Three of the fourteen objects which were reobserved showed flux increases greater than a factor of two on a time scale greater than six months. No variability was detected during the individual observations. The optical and X-ray luminosities are correlated, which suggests a common origin. However, the relationship (L sub x is approximately L sub op to the (.89 + or - .15)) found for historic radio variables may be significantly different than that reported for other radio bright sources. Some of the observed X-ray fluxes were substantially below the predicted self-Compton flux, assuming incoherent synchrotron emission and using VLBI results to constrain the size of the emission region, which suggests relativistic expansion in these sources. Normal CIV emission in two of the sources with an overpredicted Compton component suggests that although they, like BL Lac objects, have highly relativistic material apparently moving at small angle to the line of sight, they have a smaller fraction of the continuum component in the beam

  12. Jet opening angles and gamma-ray brightness of AGN

    CERN Document Server

    Pushkarev, A B; Lister, M L; Savolainen, T

    2009-01-01

    We have investigated the differences in apparent opening angles between the parsec-scale jets of the active galactic nuclei (AGN) detected by the Fermi Large Area Telescope (LAT) during its first three months of operations and those of non-LAT-detected AGN. We used 15.4 GHz VLBA observations of sources from the 2 cm VLBA MOJAVE program, a subset of which comprise the statistically complete flux density limited MOJAVE sample. We determined the apparent opening angles by analyzing transverse jet profiles from the data in the image plane and by applying a model fitting technique to the data in the (u,v) plane. Both methods provided comparable opening angle estimates. The apparent opening angles of gamma-ray bright blazars are preferentially larger than those of gamma-ray weak sources. At the same time, we have found the two groups to have similar intrinsic opening angle distributions. This suggests that the jets in gamma-ray bright AGN are oriented at preferentially smaller angles to the line of sight resulting ...

  13. The distribution of visual binaries with two bright components

    International Nuclear Information System (INIS)

    Among the 4908 stellar systems which have at least one resolvable component brighter than V = 6.00 are 115 systems with two or more resolvable components both brighter than V = 6.00. These bright stellar systems, both single and double, are modeled by a distribution convolving (1) formulas from theoretical models for stellar evolution, including giants as well as main-sequence stars, (2) an initial mass function and birth rate function, (3) a density distribution of stars as a function of distance from the Galactic plane, and (4) a distribution of mass ratios and orbital separations. One reasonably firm conclusion is that masses, even in wide binaries, are correlated: there are too many doubly bright visual binaries (DBVBs), by a factor of 3-5, to agree with the hypothesis that the component masses are selected independently from the same IMF or luminosity function. Another conclusion is that the number of DBVBs per decibel of separation a (absolute, not apparent) is not constant in the range a = 10-100,000 AU, but instead decreases slowly with increasing a. 21 refs

  14. Lattice Development for Pep-X High Brightness Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Nosochkov, Yuri; /SLAC; Cai, Yunhai; /SLAC; Wang, Min-Huey; /SLAC

    2010-08-25

    Design of PEP-X high brightness light source machine is under development at SLAC. The PEP-X is a proposed replacement for the PEP-II in the existing 2.2 km tunnel. Two of the PEP-X six arcs contain DBA type lattice providing 30 dispersion free straights suitable for 3.5 m long undulators. The lattice contains TME cells in the other four arcs and 89.3 m wiggler in a long straight section yielding a horizontal emittance of {approx}0.1 nm-rad at 4.5 GeV. The recent lattice modifications are aimed at increasing the predicted brightness and improving beam dynamic properties. The standard DBA cells are modified into supercells for providing low-{beta} undulator straights. The DBA and TME cell phase advance is better optimized. Harmonic sextupoles are added to minimize the sextupole driven resonance effects and amplitude dependent tune shift. Finally, the injection scheme is changed from vertical to horizontal plane in order to avoid large vertical amplitudes of injected beam within small vertical aperture of undulators.

  15. New low surface brightness dwarf galaxies in the Centaurus group

    CERN Document Server

    Müller, Oliver; Binggeli, Bruno

    2016-01-01

    We conducted an extensive CCD search for faint, unresolved dwarf galaxies of very low surface brightness in the whole Centaurus group region encompassing the Cen A and M 83 subgroups lying at a distance of roughly 4 and 5 Mpc, respectively. The aim is to significantly increase the sample of known Centaurus group members down to a fainter level of completeness, serving as a basis for future studies of the 3D structure of the group. Following our previous survey of 60 square degrees covering the M 83 subgroup, we extended and completed our survey of the Centaurus group region by imaging another 500 square degrees area in the g and r bands with the wide-field Dark Energy Survey Camera at the 4m Blanco telescope at CTIO. The limiting central surface brightness reached for suspected Centaurus members is $\\mu_r \\approx 29$ mag arcsec$^{-2}$, corresponding to an absolute magnitude $M_r \\approx -9.5$. The images were enhanced using different filtering techniques. We found 41 new dwarf galaxy candidates, which togethe...

  16. BRITE-Constellation: Nanosatellites for precision photometry of bright stars

    Science.gov (United States)

    Weiss, W. W.; Moffat, A. F. J.; Schwarzenberg-Czerny, A.; Koudelka, O. F.; Grant, C. C.; Zee, R. E.; Kuschnig, R.; Mochnacki, St.; Rucinski, S. M.; Matthews, J. M.; Orleański, P.; Pamyatnykh, A. A.; Pigulski, A.; Alves, J.; Guedel, M.; Handler, G.; Wade, G. A.; Scholtz, A. L.; Scholtz

    2014-02-01

    BRITE-Constellation (where BRITE stands for BRIght Target Explorer) is an international nanosatellite mission to monitor photometrically, in two colours, brightness and temperature variations of stars brighter than V ~ 4, with precision and time coverage not possible from the ground. The current mission design consists of three pairs of 7 kg nanosats (hence ``Constellation'') from Austria, Canada and Poland carrying optical telescopes (3 cm aperture) and CCDs. One instrument in each pair is equipped with a blue filter; the other, a red filter. The first two nanosats (funded by Austria) are UniBRITE, designed and built by UTIAS-SFL (University of Toronto Institute for Aerospace Studies-Space Flight Laboratory) and its twin, BRITE-Austria, built by the Technical University Graz (TUG) with support of UTIAS-SFL. They were launched on 25 February 2013 by the Indian Space Agency, under contract to the Canadian Space Agency. Each BRITE instrument has a wide field of view (~ 24 degrees), so up to 15 bright stars can be observed simultaneously in 32 × 32 sub-rasters. Photometry (with reduced precision but thorough time sampling) of additional fainter targets will be possible through on-board data processing. A critical technical element of the BRITE mission is the three-axis attitude control system to stabilize a nanosat with very low inertia. The pointing stability is better than 1.5 arcminutes rms, a significant advance by UTIAS-SFL over any previous nanosatellite. BRITE-Constellation will primarily measure p- and g-mode pulsations to probe the interiors and ages of stars through asteroseismology. The BRITE sample of many of the brightest stars in the night sky is dominated by the most intrinsically luminous stars: massive stars seen at all evolutionary stages, and evolved medium-mass stars at the very end of their nuclear burning phases (cool giants and AGB stars). The Hertzsprung-Russell diagram for stars brighter than mag V=4 from which the BRITE-Constellation sample

  17. Fluorescence analyzer for lignin

    Science.gov (United States)

    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.

  18. Fluorescent temperature sensor

    Science.gov (United States)

    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.

  19. A fluorescence scanning electron microscope

    Directory of Open Access Journals (Sweden)

    Takaaki Kanemaru

    2010-01-01

    Full Text Available Fluorescence techniques are widely used in biological research to examine molecular localization, while electron microscopy can provide unique ultrastructural information. To date, correlative images from both fluorescence and electron microscopy have been obtained separately using two different instruments, i.e. a fluorescence microscope (FM and an electron microscope (EM. In the current study, a scanning electron microscope (SEM (JEOL JXA8600 M was combined with a fluorescence digital camera microscope unit and this hybrid instrument was named a fluorescence SEM (FL-SEM. In the labeling of FL-SEM samples, both Fluolid, which is an organic EL dye, and Alexa Fluor, were employed. We successfully demonstrated that the FL-SEM is a simple and practical tool for correlative fluorescence and electron microscopy.

  20. Micro Coronal Bright Points Observed in the Quiet Magnetic Network by SOHO/EIT

    Science.gov (United States)

    Falconer, D. A.; Moore, R. L.; Porter, J. G.

    1997-01-01

    When one looks at SOHO/EIT Fe XII images of quiet regions, one can see the conventional coronal bright points (> 10 arcsec in diameter), but one will also notice many smaller faint enhancements in brightness (Figure 1). Do these micro coronal bright points belong to the same family as the conventional bright points? To investigate this question we compared SOHO/EIT Fe XII images with Kitt Peak magnetograms to determine whether the micro bright points are in the magnetic network and mark magnetic bipoles within the network. To identify the coronal bright points, we applied a picture frame filter to the Fe XII images; this brings out the Fe XII network and bright points (Figure 2) and allows us to study the bright points down to the resolution limit of the SOHO/EIT instrument. This picture frame filter is a square smoothing function (hlargelyalf a network cell wide) with a central square (quarter of a network cell wide) removed so that a bright point's intensity does not effect its own background. This smoothing function is applied to the full disk image. Then we divide the original image by the smoothed image to obtain our filtered image. A bright point is defined as any contiguous set of pixels (including diagonally) which have enhancements of 30% or more above the background; a micro bright point is any bright point 16 pixels or smaller in size. We then analyzed the bright points that were fully within quiet regions (0.6 x 0.6 solar radius) centered on disk center on six different days.

  1. Comparative Analysis of a Transition Region Bright Point with a Blinker and Coronal Bright Point Using Multiple EIS Emission Lines

    CERN Document Server

    Orange, N Brice; Chesny, David L; Patel, Maulik; Hesterly, Katie; Preuss, Lauren; Neira, Chantale; Turner, Niescja E

    2015-01-01

    Since their discovery twenty year ago, transition region bright points (TRBPs) have never been observed spectroscopically. Bright point properties have not been compared with similar transition region and coronal structures. In this work we have investigated three transient quiet Sun brightenings including a TRBP, a coronal BP (CBP) and a blinker. We use time-series observations of the extreme ultraviolet emission lines of a wide range of temperature T (log T = 5.3 - 6.4) from the EUV imaging spectrometer (EIS) onboard the Hinode satellite. We present the EIS temperature maps and Doppler maps, which are compared with magnetograms from the Michelson Doppler Imager (MDI) onboard the SOHO satellite. Doppler velocities of the TR BP and blinker are <,25 km s$^{-1}$, which is typical of transient TR phenomena. The Dopper velocities of the CBP were found to be < 20 km s^{-1} with exception of those measured at log T = 6.2 where a distinct bi-directional jet is observed. From an EM loci analysis we find evidenc...

  2. Modelling of microcracks image treated with fluorescent dye

    Science.gov (United States)

    Glebov, Victor; Lashmanov, Oleg U.

    2015-06-01

    The main reasons of catastrophes and accidents are high level of wear of equipment and violation of the production technology. The methods of nondestructive testing are designed to find out defects timely and to prevent break down of aggregates. These methods allow determining compliance of object parameters with technical requirements without destroying it. This work will discuss dye penetrant inspection or liquid penetrant inspection (DPI or LPI) methods and computer model of microcracks image treated with fluorescent dye. Usually cracks on image look like broken extended lines with small width (about 1 to 10 pixels) and ragged edges. The used method of inspection allows to detect microcracks with depth about 10 or more micrometers. During the work the mathematical model of image of randomly located microcracks treated with fluorescent dye was created in MATLAB environment. Background noises and distortions introduced by the optical systems are considered in the model. The factors that have influence on the image are listed below: 1. Background noise. Background noise is caused by the bright light from external sources and it reduces contrast on the objects edges. 2. Noises on the image sensor. Digital noise manifests itself in the form of randomly located points that are differing in their brightness and color. 3. Distortions caused by aberrations of optical system. After passing through the real optical system the homocentricity of the bundle of rays is violated or homocentricity remains but rays intersect at the point that doesn't coincide with the point of the ideal image. The stronger the influence of the above-listed factors, the worse the image quality and therefore the analysis of the image for control of the item finds difficulty. The mathematical model is created using the following algorithm: at the beginning the number of cracks that will be modeled is entered from keyboard. Then the point with random position is choosing on the matrix whose size is

  3. Data Analysis for Total Internal Reflection Fluorescence Microscopy.

    Science.gov (United States)

    Asbury, Charles L

    2016-01-01

    In the microscopes we use to analyze total internal reflection fluorescence (TIRF), the emitted fluorescence is split chromatically, using dichroic filters, into either two or three different colors ("channels"). In our two-color instrument, the green emission wavelengths (405-488 nm; for imaging green fluorescent protein [GFP]-tagged proteins) and far-red emission wavelengths (650-800 nm; for imaging Alexa-647-labeled microtubules) are projected onto the upper and lower halves, respectively, of a single camera. A single filter can be swapped to collect near-red wavelengths (561-640 nm; for imaging mCherry, or Alexa-568-labeled microtubules) instead of far-red. Our three-color instrument is very similar except that the green, near-red, and far-red color ranges are projected onto three separate cameras. In either case, the different colors can be imaged simultaneously. Typically, we collect images at 10 frames/sec for ∼200 sec. We have developed a series of semiautomated image analysis programs, written in LabView, to obtain the brightness, residence time, and mobility of individual particles bound to single microtubules. The basic analysis steps are straightforward and could also be implemented using ImageJ or Matlab. For convenience, this protocol describes the analysis of a single microtubule. Data from many microtubules across many experimental trials are needed to obtain robust conclusions that are independent of stochastic and trial-to-trial variability. PMID:27140913

  4. The dearth of nuclear star clusters in bright galaxies

    Science.gov (United States)

    Arca-Sedda, M.; Capuzzo-Dolcetta, R.; Spera, M.

    2016-03-01

    We investigate the interaction of a massive globular cluster (GC) with a super massive black hole (SMBH), located at the centre of its host galaxy, by means of direct N-body simulations. The results show that tidal distortions induced by the stellar background and the SMBH act on a time shorter than that of dynamical friction decay for a 106 M⊙ GC whenever the SMBH mass exceeds ˜108 M⊙. This implies an almost complete dissolution of the infalling GC before it reaches the inner region (≲5 pc) of the parent galaxy. The generalization of this result to a larger sample of infalling GCs shows that such destructive process may prevent the formation and growth of a bright galactic nucleus. Another interesting, serendipitous, result we obtained is that the close interaction between the SMBH and the GC produces a `wave' of stars that escape from the cluster and, in a fraction, even from the whole galaxy.

  5. Observations of neutral carbon in the NGC 1977 bright rim

    Science.gov (United States)

    Wootten, A.; Phillips, T. G.; Beichman, C. A.; Frerking, M.

    1982-01-01

    Strong neutral carbon emission at 610 microns (492 GHz) has been detected from a bright-rimmed cloud abutting the H II region NGC 1977. The similarity of velocity and width between (C-13)O and C I lines suggests that both lines originate in the same region. A model for the density and temperature structure of the cloud, based on (C-13)O and (C-12)O observations, has been used to estimate the carbon abundance. The abundances of both C I and (C-13)O increase with depth into the cloud away from the rim. The carbon abundance reaches its peak value nearer the rim than does the (C-13)O abundance. This variation in the relative abundance distributions of CO and C I confirms the importance of photodissociation in the chemistry of molecular clouds, and of the C I line to studies of the interaction of hot stars with clouds.

  6. An in-house developed annular bright field detection system

    International Nuclear Information System (INIS)

    Annular bright field (ABF) detectors have been developed in the last few years allowing the direct imaging of low-Z atoms from oxygen down to hydrogen. These types of detectors are now available as standard attachments for the latest generation of top-end electron microscopes. However these systems cannot always be installed in previous generation microscopes. In this paper we report the preliminary results of an in-house implementation of a ABF detection system on a CEOS aberration corrected JEOL 2200FS STEM. This has been obtained by exploiting the standard BF detector coupled with a high vacuum compatible, X-ray tight and retractable shadowing mechanism. This results in the acquisition of near zero-angle scattered electrons with inner collection semi-angle from 2.0 mrad to 23 mrad and outer semi-angle in the range from 3.0 mrad to 35 mrad. The characteristics and performances of this ABF detection system are discussed

  7. Contribution of Bright Extragalactic Radio Sources to Microwave Anisotropy

    CERN Document Server

    Sokasian, A; Smoot, G F; Sokasian, Aaron; Gawiser, Eric; Smoot, George F.

    2001-01-01

    We estimate the contribution of extragalactic radio sources to fluctuations in sky temperature over the range of frequencies (10-300 GHz) used for Cosmic Microwave Background (CMB) anisotropy measurements. CMB anisotropy observations at high resolution and low frequencies are especially sensitive to this foreground. We have compiled a catalog of 2207 bright radio sources, including 758 sources with flux measurements at 90 GHz. We develop a method to extrapolate the source spectra and predict skymaps of extragalactic radio sources at instrument resolutions of 10 arcmin to 10 degrees FWHM. Our results indicate that the brightest sources will dominate microwave anisotropy for a wide range of resolutions and frequencies. Our skymaps predict the location and flux of the brightest radio sources at each frequency, making it straightforward to develop a template for masking the pixels containing them. This masking should be sufficient to protect high resolution CMB anisotropy observations from unacceptable radio sour...

  8. Beam position monitors for the high brightness lattice

    International Nuclear Information System (INIS)

    Engineering developments associated with the high brightness lattice and the projected change in machine operating parameters will inherently affect the diagnostics systems and devices installed at present in the storage ring. This is particularly true of the beam position monitoring (BPI) system. The new sixteen unit cell lattice with its higher betatron tune values and the limited space available in the redesigned machine straights for fitting standard BPI vessels forces a fundamental re-evaluation of the beam position monitor system. The design aims for the new system are based on accepting the space limitations imposed while still providing the monitor points required to give good radial and vertical closed orbit plots. The locations of BPI's in the redesigned machine straights is illustrated. A description of the new BPI assemblies and their calibration is given. The BPI's use capacitance button type pick-ups; their response is described. (U.K.)

  9. CCD Photometry of bright stars using objective wire mesh

    International Nuclear Information System (INIS)

    Obtaining accurate photometry of bright stars from the ground remains problematic due to the danger of overexposing the target and/or the lack of suitable nearby comparison stars. The century-old method of using objective wire mesh to produce multiple stellar images seems promising for the precise CCD photometry of such stars. Furthermore, our tests on β Cep and its comparison star, differing by 5 mag, are very encouraging. Using a CCD camera and a 20 cm telescope with the objective covered by a plastic wire mesh, in poor weather conditions, we obtained differential photometry with a precision of 4.5 mmag per two minute exposure. Our technique is flexible and may be tuned to cover a range as big as 6-8 mag. We discuss the possibility of installing a wire mesh directly in the filter wheel.

  10. Relationships between brightness of nighttime lights and population density

    Science.gov (United States)

    Naizhuo, Z.

    2012-12-01

    Brightness of nighttime lights has been proven to be a good proxy for socioeconomic and demographic statistics. Moreover, the satellite nighttime lights data have been used to spatially disaggregate amounts of gross domestic product (GDP), fossil fuel carbon dioxide emission, and electric power consumption (Ghosh et al., 2010; Oda and Maksyutov, 2011; Zhao et al., 2012). Spatial disaggregations were performed in these previous studies based on assumed linear relationships between digital number (DN) value of pixels in the nighttime light images and socioeconomic data. However, reliability of the linear relationships was never tested due to lack of relative high-spatial-resolution (equal to or finer than 1 km × 1 km) statistical data. With the similar assumption that brightness linearly correlates to population, Bharti et al. (2011) used nighttime light data as a proxy for population density and then developed a model about seasonal fluctuations of measles in West Africa. The Oak Ridge National Laboratory used sub-national census population data and high spatial resolution remotely-sensed-images to produce LandScan population raster datasets. The LandScan population datasets have 1 km × 1 km spatial resolution which is consistent with the spatial resolution of the nighttime light images. Therefore, in this study I selected 2008 LandScan population data as baseline reference data and the contiguous United State as study area. Relationships between DN value of pixels in the 2008 Defense Meteorological Satellite Program's Operational Linescan System (DMSP-OLS) stable light image and population density were established. Results showed that an exponential function can more accurately reflect the relationship between luminosity and population density than a linear function. Additionally, a certain number of saturated pixels with DN value of 63 exist in urban core areas. If directly using the exponential function to estimate the population density for the whole brightly

  11. Brightness Factor Matching for Gesture Recognition System Using Scaled Normalization

    Directory of Open Access Journals (Sweden)

    Mokhtar M. Hasan

    2011-04-01

    Full Text Available The rich information found in the human gestures makes it possible to be used for another languagewhich is called the sign language, this kind of intuitive interface can be used with human-mademachines/devices as well, we herein going to introduce a new gesture recognition system based on imageblocking and the gestures are recognized using our suggested brightness factor matching algorithm, wehave applied two different feature extraction techniques, the first one based on features extracted fromedge information and the other one based on a new technique for centre of mass normalization based onblock scaling instead of coordinates shifting; we have achieved 83.3% recognition accuracy in firsttechnique with significant and satisfactory recognition time of 1.5 seconds per gesture, and 96.6 %recognition accuracy with recognition time less than one second by eliminating the use of edge detectorwhich consumes time, this paper focuses on appearance based gestures.

  12. Sharp and Bright Photoluminescence Emission of Single Crystalline Diacetylene Nanoparticles

    CERN Document Server

    Kima, Seokho; Kima, Hyeong Tae; Cuic, Chunzhi; Park, Dong Hyuk

    2016-01-01

    Amorphous nanoparticles (NPs) of diacetylene (DA) molecules were prepared by using a reprecipitation method. After crystallization through solvent-vapor annealing process, the highly crystalline DA NPs show different structural and optical characteristics compared with the amorphous DA NPs. The single crystal structure of DA NPs was confirmed by high-resolution transmission electron microscopy (HR-TEM) and wide angle X-ray scattering (WAXS). The luminescence color and photoluminescence (PL) characteristics of the DA NPs were measured using color charge-coupled device (CCD) images and high-resolution laser confocal microscope (LCM). The crystalline DA NPs emit bright green light emission compared with amorphous DA NPs and the main PL peak of the crystalline DA NPs exhibits relative narrow and blue shift phenomena due to enhanced interaction between DA molecular in the nano-size crystal structure.

  13. Dark matter in bright X-ray ellipticals

    International Nuclear Information System (INIS)

    The authors investigate the total mass distribution of bright X-ray ellipticals (with diffuse X-ray luminosity higher than 1041 erg s-1) studying the gravitational equilibrium of three component models constituted by stars, hot diffuse gas and dark matter. Assuming a constant mass-to-light ratio for the stars described with anisotropic distribution function in phase space, an emission in X-ray from the hot diffuse gas and a dark component in form of massive fermions, they derive constraints on the dark matter distribution by using optical and X-ray data. They specialize their investigation to the elliptical NGC 4472 for which spectroscopic data of relatively good quality are available

  14. CCD Photometry of bright stars using objective wire mesh

    Energy Technology Data Exchange (ETDEWEB)

    Kamiński, Krzysztof; Zgórz, Marika [Astronomical Observatory Institute, Faculty of Physics, A. Mickiewicz University, Słoneczna 36, 60-286 Poznań (Poland); Schwarzenberg-Czerny, Aleksander, E-mail: chrisk@amu.edu.pl [Copernicus Astronomical Centre, ul. Bartycka 18, PL 00-716 Warsaw (Poland)

    2014-06-01

    Obtaining accurate photometry of bright stars from the ground remains problematic due to the danger of overexposing the target and/or the lack of suitable nearby comparison stars. The century-old method of using objective wire mesh to produce multiple stellar images seems promising for the precise CCD photometry of such stars. Furthermore, our tests on β Cep and its comparison star, differing by 5 mag, are very encouraging. Using a CCD camera and a 20 cm telescope with the objective covered by a plastic wire mesh, in poor weather conditions, we obtained differential photometry with a precision of 4.5 mmag per two minute exposure. Our technique is flexible and may be tuned to cover a range as big as 6-8 mag. We discuss the possibility of installing a wire mesh directly in the filter wheel.

  15. Quasi-Periodic Oscillation of a Coronal Bright Point

    CERN Document Server

    Samanta, Tanmoy; Tian, Hui

    2015-01-01

    Coronal bright points (BPs) are small-scale luminous features seen in the solar corona. Quasi-periodic brightenings are frequently observed in the BPs and are generally linked with underneath magnetic flux changes. We study the dynamics of a BP seen in the coronal hole using the Atmospheric Imaging Assembly (AIA) images, the Helioseismic and Magnetic Imager (HMI) magnetogram on board the Solar Dynamics Observatory (SDO) and spectroscopic data from the newly launched Interface Region Imaging Spectrograph (IRIS). The detailed analysis shows that the BP evolves throughout our observing period along with changes in underlying photospheric magnetic flux and shows periodic brightenings in different EUV and FUV images. With highest possible spectral and spatial resolution of IRIS, we attempted to identify the sources of these oscillations. IRIS sit and stare observation provided a unique opportunity to study the time evolution of one foot point of the BP as the slit position crossed it. We noticed enhanced line prof...

  16. Do Baryons Alter the Halos of Low Surface Brightness Galaxies?

    CERN Document Server

    de Naray, Rachel Kuzio

    2011-01-01

    High-quality observations of dark matter-dominated low surface brightness (LSB) galaxies indicate that, in contrast to the triaxial, centrally-concentrated cuspy halos formed in collisionless simulations of halo assembly, these galaxies reside in round, roughly constant density cored halos. In order to reconcile these data with galaxy formation in the context of LCDM, processes that alter the shape and density structure of the inner halo are required. We compile observational properties of LSB galaxies to evaluate the plausibility that a previously higher baryonic mass content and feedback from star formation can modify the dark matter halos of these galaxies. We also compare the properties of bulgeless disk galaxies formed in recent simulations to the LSB galaxy sample. We find that observational constraints on LSB galaxy star formation histories, structure, and kinematics make it difficult for baryonic physics to sphericalize and decrease the central density of the dark matter halos of LSB galaxies.

  17. Coupling and stability of bright holographic soliton parirs

    Institute of Scientific and Technical Information of China (English)

    Liu Jin-Song; Hao Zhong-Hua

    2004-01-01

    The coupling effect and stability property of symmetric bright holographic soliton pairs have been investigated numerically. Results show that when any one of the two solitary beams from a pair is perturbed in amplitude or width,both beams will be affected by such a perturbation via the coupling effect between the beams, thus resulting in both beams propagating in the medium without a constant shape; however, these two solitary beams are still stable against small perturbations. When both solitary beams from a pair are perturbed simultaneously in amplitude, for some given absolute values of the perturbations, the two beams are stable against these perturbations if both beams are perturbed with the same sign, whereas are unstable with the different signs. When the two beams are simultaneously perturbed in width, both beams exhibit their stability property similar to that when only one beam is perturbed no matter whether both perturbations have the same or different signs.

  18. A catalogue of bright (K < 9) M dwarfs

    CERN Document Server

    Frith, J; Jones, H R A; Barnes, J R; Pavlenko, Y; Martin, E L; Brown, C; Kuznetsov, M K; Marocco, F; Tata, R; Cappetta, M

    2013-01-01

    Using the Position and Proper Motion Extended-L (PPMXL) catalogue, we have used optical and near-infrared colour cuts together with a reduced proper motion cut to find bright M dwarfs for future exoplanet transit studies. PPMXL's low proper motion uncertainties allow us to probe down to smaller proper motions than previous similar studies. We have combined unique objects found with this method to that of previous work to produce 8479 K<9 M dwarfs. Low resolution spectroscopy was obtained of a sample of the objects found using this selection method to gain statistics on their spectral type and physical properties. Results show a spectral type range of K7-M4V. This catalogue is the most complete collection of K<9 M dwarfs currently available and is made available here.

  19. Investigation of fundamental limits to beam brightness available from photoinjectors

    Energy Technology Data Exchange (ETDEWEB)

    Bazarov, Ivan [Cornell Univ., Ithaca, NY (United States)

    2015-07-09

    The goal of this project was investigation of fundamental limits to beam brightness available from photoinjectors. This basic research in accelerator physics spanned over 5 years aiming to extend the fundamental understanding of high average current, low emittance sources of relativistic electrons based on photoemission guns, a necessary prerequisite for a new generation of coherent X-ray synchrotron radiation facilities based on continuous duty superconducting linacs. The program focused on two areas critical to making advances in the electron source performance: 1) the physics of photocathodes for the production of low emittance electrons and 2) control of space charge forces in the immediate vicinity to the cathode via 3D laser pulse shaping.

  20. Dark matter within high surface brightness spiral galaxies

    CERN Document Server

    Kranz, T; Rix, H W; Kranz, Thilo; Slyz, Adrianne; Rix, Hans-Walter

    2003-01-01

    We present results from a detailed dynamical analysis of five high surface brightness, late type spirals, studied with the aim to quantify the luminous-to-dark matter ratio inside their optical radii. The galaxies' stellar light distribution and gas kinematics have been observed and compared to hydrodynamic gas simulations, which predict the 2D gas dynamics arising in response to empirical gravitational potentials, which are combinations of differing stellar disk and dark halo contributions. The gravitational potential of the stellar disk was derived from near-infrared photometry, color-corrected to constant (M/L); the dark halo was modelled by an isothermal sphere with a core. Hydrodynamic gas simulations were performed for each galaxy for a sequence of five different mass fractions of the stellar disk and for a wide range of spiral pattern speeds. These two parameters mainly determine the modelled gas distribution and kinematics. The agreement between the non-axisymmetric part of the simulated and observed ...

  1. The Stability of F-star Brightness on Century Timescales

    CERN Document Server

    Lund, Michael B; Stassun, Keivan G; Hippke, Michael; Angerhausen, Daniel

    2016-01-01

    The century-long photometric record of the DASCH project provides a unique window into the variability of stars normally considered to be photometrically inactive. In this paper, we look for long-term trends in the brightness of F stars, with particular attention to KIC 8462852,an F3 main sequence star that has been identified as significant short-term variability according to Kepler observations. Although a simple search for variability suggests long-term dimming of a number of F stars, we find that such trends are artifacts of the 'Menzel Gap' in the DASCH data. That includes the behavior of KIC 8462852, which we believe is consistent with constant flux over the full duration of observations. We do, however, present a selection of F stars thatdo have significant photometric trends, even after systematics are taken into account.

  2. VLA observations of objects in the Palomar Bright Quasar Survey

    International Nuclear Information System (INIS)

    Results on the VLA observations (with 18 arcsec resolution) of all 114 objects from the Palomar Bright Quasar Survey (BQS) are presented, and the relation between the radio luminosity and optical luminosity is discussed. It was found that most of the BQS quasars are radio quiet and have a radio flux density close to that of the optical flux density; however, 15-20 percent of the quasars are radio loud and are much brighter at radio than at optical wavelengths. The radio luminosity function was derived. It is shown that the radio emission from high-red-shift (z greater than 0.5) quasars is dominated by compact components; most quasars with R above 100 have small red shifts. 39 refs

  3. A turbulent model for the surface brightness of extragalactic jets

    CERN Document Server

    Lorenzo, Zaninetti

    2009-01-01

    This paper summarizes the known physics of turbulent jets observed in laboratory experiments. The formula, which gives the power released in turbulence describes the concentration of turbulence/relativistic particles in each point of the astrophysical jets. The same expression is also used to analyze the power released in turbulence in the case of pipe and non Newtonian fluids. Through an integral operation it is possible to deduce the intensity of synchrotron radiation for a profile perpendicular or not to a straight jet, a 2D map for a perpendicular, randomly oriented straight jet as well as a 2D map of complex trajectories such as NCC4061 and 3C31. Presented here is a simulation of the spectral index in brightness of 3C273 as well as a 2D map of the degree of linear polarization. The Sobel operator is applied to the theoretical 2D maps of straight perpendicular jets.

  4. The National Synchrotron Light Source, Part I: Bright Idea

    International Nuclear Information System (INIS)

    The National Synchrotron Light Source (NSLS) was the first facility designed and built specifically for producing and exploiting synchrotron radiation. It was also the first facility to incorporate the Chasman-Green lattice for maximizing brightness. The NSLS was a $24-million project conceived about 1970. It was officially proposed in 1976, and its groundbreaking took place in 1978. Its construction was a key episode in Brookhaven's history, in the transition of synchrotron radiation from a novelty to a commodity, and in the transition of synchrotron-radiation scientists from parasitic to autonomous researchers. The way the machine was conceived, designed, promoted, and constructed illustrates much both about the tensions and tradeoffs faced by large scientific projects in the age of big science. In this article, the first of two parts, I cover the conception, design, and planning of the NSLS up to its groundbreaking. Part II, covering its construction, will appear in the next issue.

  5. Silicon-chip source of bright photon pairs.

    Science.gov (United States)

    Jiang, Wei C; Lu, Xiyuan; Zhang, Jidong; Painter, Oskar; Lin, Qiang

    2015-08-10

    Integrated quantum photonics relies critically on the purity, scalability, integrability, and flexibility of a photon source to support diverse quantum functionalities on a single chip. Here we report a chip-scale photon-pair source on the silicon-on-insulator platform that utilizes dramatic cavity-enhanced four-wave mixing in a high-Q silicon microdisk resonator. The device is able to produce high-quality photon pairs at different wavelengths with a high spectral brightness of 6.24×10(7) pairs/s/mW(2)/GHz and photon-pair correlation with a coincidence-to-accidental ratio of 1386 ± 278 while pumped with a continuous-wave laser. The superior performance, together with the structural compactness and CMOS compatibility, opens up a great avenue towards quantum silicon photonics with capability of multi-channel parallel information processing for both integrated quantum computing and long-haul quantum communication. PMID:26367942

  6. High Brightness Proton Beams for LHC: Needs and Means

    CERN Document Server

    Benedikt, Michael; High Energy High Intensity Hadron Beams (HHH 2004)

    2005-01-01

    Experiments [1, 2] have proven that the LHC injector chain can deliver a proton beam with the nominal characteristics (bunch intensity Nb=1.15E11 protons per bunch (ppb) in normalised rms transverse emittances of 3.5 mm.mrad), but cannot reach the ultimate performance (1.7E11 ppb in the same emittances). Moreover, in the longer term, an even higher beam brightness is required by all methods considered for increasing the LHC luminosity beyond the present ultimate level. Improvements and/or new processes are therefore needed, especially in the low energy accelerators. A number of solutions have already been imagined for the PS complex that involve new linac(s) or/and sophisticated beam gymnastics. The present capabilities and limitations of the accelerator chain are described. The needs of the possible LHC luminosity upgrades are outlined, the proposed improvements are explained and their features and performance are compared.

  7. Hacking commercial quantum cryptography systems by tailored bright illumination

    CERN Document Server

    Lydersen, Lars; Wittmann, Christoffer; Elser, Dominique; Skaar, Johannes; Makarov, Vadim; 10.1038/NPHOTON.2010.214

    2010-01-01

    The peculiar properties of quantum mechanics allow two remote parties to grow a private, secret key, even if the eavesdropper can do anything permitted by the laws of nature. In quantum key distribution (QKD) the parties exchange non-orthogonal or entangled quantum states to generate quantum correlated classical data. Consequently, QKD implementations always rely on detectors to measure the relevant quantum property of the signal states. However, practical detectors are not only sensitive to quantum states. Here we show how an eavesdropper can exploit such deviations from the ideal behaviour: We demonstrate experimentally how the detectors in two commercially available QKD systems can be fully remote controlled using specially tailored bright illumination. This makes it possible to acquire the full secret key without leaving any trace; we propose an eavesdropping apparatus built of off-the-shelf components. The loophole is likely to be present in most QKD systems using avalanche photo diodes (APDs) to detect ...

  8. Sizes of water-soluble luminescent quantum dots measured by fluorescence correlation spectroscopy

    International Nuclear Information System (INIS)

    In this paper, fluorescence correlation spectroscopy (FCS) was applied to measure the size of water-soluble quantum dots (QDs). The measurements were performed on a home-built FCS system based on the Stokes-Einstein equation. The obtained results showed that for bare CdTe QDs the sizes from FCS were larger than the ones from transmission electron microscopy (TEM). The brightness of QDs was also evaluated using FCS technique. It was found that the stability of the surface chemistry of QDs would be significantly improved by capping it with hard-core shell. Our data demonstrated that FCS is a simple, fast, and effective method for characterizing the fluorescent quantum dots, and is especially suitable for determining the fluorescent nanoparticles less than 10 nm in water solution

  9. Synthesis, modification, bioconjugation of silica coated fluorescent quantum dots and their application for mycotoxin detection.

    Science.gov (United States)

    Goftman, Valentina V; Aubert, Tangi; Ginste, Dries Vande; Van Deun, Rik; Beloglazova, Natalia V; Hens, Zeger; De Saeger, Sarah; Goryacheva, Irina Yu

    2016-05-15

    To create bright and stable fluorescent biolabels for immunoassay detection of mycotoxin deoxynivalenol in food and feed, CdSe/CdS/ZnS core-shell quantum dots (QDs) were encapsulated in silica nanoparticles through a water-in-oil reverse microemulsion process. The optical properties and stability of the obtained silica coated QDs (QD@SiO2), modified with amino, carboxyl and epoxy groups and stabilized with polyethylene glycol fragments, were characterized in order to assess their bioapplicability. The developed co-condensation techniques allowed maintaining 80% of the initial fluorescent properties and yielded stable fluorescent labels that could be easily activated and bioconjugated. Further, the modified QD@SiO2 were efficiently conjugated with antibodies and applied as a novel label in a microtiter plate based immunoassay and a quantitative column-based rapid immunotest for deoxynivalenol detection with IC50 of 473 and 20 ng/ml, respectively. PMID:26745794

  10. Synthesis and characterisation of highly fluorescent core–shell nanoparticles based on Alexa dyes

    International Nuclear Information System (INIS)

    Current and future developments in the emerging field of nanobiotechnology are closely linked to the rational design of novel fluorescent nanomaterials, e.g. for biosensing and imaging applications. Here, the synthesis of bright near infrared (NIR)-emissive nanoparticles based on the grafting of silica nanoparticles (SNPs) with 3-aminopropyl triethoxysilane (APTES) followed by covalent attachment of Alexa dyes and their subsequent shielding by an additional silica shell are presented. These nanoparticles were investigated by dynamic light scattering (DLS), transmission electron microscopy (TEM) and fluorescence spectroscopy. TEM studies revealed the monodispersity of the initially prepared and fluorophore-labelled silica particles and the subsequent formation of raspberry-like structures after addition of a silica precursor. Measurements of absolute fluorescence quantum yields of these scattering particle suspensions with an integrating sphere setup demonstrated the influence of dye labelling density-dependent fluorophore aggregation on the signaling behaviour of such nanoparticles.

  11. Synthesis and characterisation of highly fluorescent core-shell nanoparticles based on Alexa dyes

    Energy Technology Data Exchange (ETDEWEB)

    Natte, Kishore; Behnke, Thomas; Orts-Gil, Guillermo, E-mail: guillermo.orts-gil@bam.de; Wuerth, Christian; Friedrich, Joerg F.; Oesterle, Werner; Resch-Genger, Ute, E-mail: ute.resch@bam.de [BAM Federal Institute for Materials Research and Testing (Germany)

    2012-02-15

    Current and future developments in the emerging field of nanobiotechnology are closely linked to the rational design of novel fluorescent nanomaterials, e.g. for biosensing and imaging applications. Here, the synthesis of bright near infrared (NIR)-emissive nanoparticles based on the grafting of silica nanoparticles (SNPs) with 3-aminopropyl triethoxysilane (APTES) followed by covalent attachment of Alexa dyes and their subsequent shielding by an additional silica shell are presented. These nanoparticles were investigated by dynamic light scattering (DLS), transmission electron microscopy (TEM) and fluorescence spectroscopy. TEM studies revealed the monodispersity of the initially prepared and fluorophore-labelled silica particles and the subsequent formation of raspberry-like structures after addition of a silica precursor. Measurements of absolute fluorescence quantum yields of these scattering particle suspensions with an integrating sphere setup demonstrated the influence of dye labelling density-dependent fluorophore aggregation on the signaling behaviour of such nanoparticles.

  12. A bright neutron source driven by relativistic transparency of solids

    Science.gov (United States)

    Roth, M.; Jung, D.; Falk, K.; Guler, N.; Deppert, O.; Devlin, M.; Favalli, A.; Fernandez, J.; Gautier, D. C.; Geissel, M.; Haight, R.; Hamilton, C. E.; Hegelich, B. M.; Johnson, R. P.; Kleinschmidt, A.; Merrill, F.; Schaumann, G.; Schoenberg, K.; Schollmeier, M.; Shimada, T.; Taddeucci, T.; Tybo, J. L.; Wagner, F.; Wender, S. A.; Wilde, C. H.; Wurden, G. A.

    2016-03-01

    Neutrons are a unique tool to alter and diagnose material properties and excite nuclear reactions with a large field of applications. It has been stated over the last years, that there is a growing need for intense, pulsed neutron sources, either fast or moderated neutrons for the scientific community. Accelerator based spallation sources provide unprecedented neutron fluxes, but could be complemented by novel sources with higher peak brightness that are more compact. Lasers offer the prospect of generating a very compact neutron source of high peak brightness that could be linked to other facilities more easily. We present experimental results on the first short pulse laser driven neutron source powerful enough for applications in radiography. For the first time an acceleration mechanism (BOA) based on the concept of relativistic transparency has been used to generate neutrons. This mechanism not only provides much higher particle energies, but also accelerated the entire target volume, thereby circumventing the need for complicated target treatment and no longer limited to protons as an intense ion source. As a consequence we have demonstrated a new record in laser-neutron production, not only in numbers, but also in energy and directionality based on an intense deuteron beam. The beam contained, for the first time, neutrons with energies in excess of 100 MeV and showed pronounced directionality, which makes then extremely useful for a variety of applications. The results also address a larger community as it paves the way to use short pulse lasers as a neutron source. They can open up neutron research to a broad academic community including material science, biology, medicine and high energy density physics as laser systems become more easily available to universities and therefore can complement large scale facilities like reactors or particle accelerators. We believe that this has the potential to increase the user community for neutron research largely.

  13. SURFACE BRIGHTNESS PROFILES OF DWARF GALAXIES. I. PROFILES AND STATISTICS

    International Nuclear Information System (INIS)

    Radial surface brightness profiles of spiral galaxies are classified into three types: (I) single exponential, or the light falls off with one exponential to a break before falling off (II) more steeply, or (III) less steeply. Profile breaks are also found in dwarf disks, but some dwarf Type IIs are flat or increasing out to a break before falling off. Here we re-examine the stellar disk profiles of 141 dwarfs: 96 dwarf irregulars (dIms), 26 Blue Compact Dwarfs (BCDs), and 19 Magellanic-type spirals (Sms). We fit single, double, or even triple exponential profiles in up to 11 passbands: GALEX FUV and NUV, ground-based UBVJHK and Hα, and Spitzer 3.6 and 4.5 μm. We find that more luminous galaxies have brighter centers, larger inner and outer scale lengths, and breaks at larger radii; dwarf trends with MB extend to spirals. However, the V-band break surface brightness is independent of break type, MB , and Hubble type. Dwarf Type II and III profiles fall off similarly beyond the breaks but have different interiors and IIs break ∼twice as far as IIIs. Outer Type II and III scale lengths may have weak trends with wavelength, but pure Type II inner scale lengths clearly decrease from the FUV to visible bands whereas Type III inner scale lengths increase with redder bands. This suggests the influence of different star formation histories on profile type, but nonetheless the break location is approximately the same in all passbands. Dwarfs continue trends between profile and Hubble types such that later-type galaxies have more Type II but fewer Type I and III profiles than early-type spirals. BCDs and Sms are over-represented as Types III and II, respectively, compared to dIms

  14. Differential Rotation via Tracking of Coronal Bright Points.

    Science.gov (United States)

    McAteer, James; Boucheron, Laura E.; Osorno, Marcy

    2016-05-01

    The accurate computation of solar differential rotation is important both as a constraint for, and evidence towards, support of models of the solar dynamo. As such, the use of Xray and Extreme Ultraviolet bright points to elucidate differential rotation has been studied in recent years. In this work, we propose the automated detection and tracking of coronal bright points (CBPs) in a large set of SDO data for re-evaluation of solar differential rotation and comparison to other results. The big data aspects, and high cadence, of SDO data mitigate a few issues common to detection and tracking of objects in image sequences and allow us to focus on the use of CBPs to determine differential rotation. The high cadence of the data allows to disambiguate individual CBPs between subsequent images by allowing for significant spatial overlap, i.e., by the fact that the CBPs will rotate a short distance relative to their size. The significant spatial overlap minimizes the effects of incorrectly detected CBPs by reducing the occurrence of outlier values of differential rotation. The big data aspects of the data allows to be more conservative in our detection of CBPs (i.e., to err on the side of missing CBPs rather than detecting extraneous CBPs) while still maintaining statistically larger populations over which to study characteristics. The ability to compute solar differential rotation through the automated detection and tracking of a large population of CBPs will allow for further analyses such as the N-S asymmetry of differential rotation, variation of differential rotation over the solar cycle, and a detailed study of the magnetic flux underlying the CBPs.

  15. Multiple dark-bright solitons in atomic Bose-Einstein condensates

    Energy Technology Data Exchange (ETDEWEB)

    Yan, D.; Kevrekidis, P. G. [Department of Mathematics and Statistics, University of Massachusetts, Amherst, Massachusetts 01003-4515 (United States); Chang, J. J.; Hamner, C.; Engels, P. [Department of Physics and Astronomy, Washington State University, Pullman, Washington 99164 (United States); Achilleos, V.; Frantzeskakis, D. J. [Department of Physics, University of Athens, Panepistimiopolis, Zografos, GR-157 84 Athens (Greece); Carretero-Gonzalez, R. [Nonlinear Dynamical Systems Group, Department of Mathematics and Statistics and Computational Science Research Center, San Diego State University, San Diego, California 92182-7720 (United States); Schmelcher, P. [Zentrum fuer Optische Quantentechnologien, Universitaet Hamburg, Luruper Chaussee 149, D-22761 Hamburg (Germany)

    2011-11-15

    Motivated by recent experimental results, we present a systematic theoretical analysis of dark-bright-soliton interactions and multiple-dark-bright-soliton complexes in atomic two-component Bose-Einstein condensates. We study analytically the interactions between two dark-bright solitons in a homogeneous condensate and then extend our considerations to the presence of the trap. We illustrate the existence of robust stationary dark-bright-soliton ''molecules,'' composed of two or more solitons, which are formed due to the competition of the interaction forces between the dark- and bright-soliton components and the trap force. Our analysis is based on an effective equation of motion, derived for the distance between two dark-bright solitons. This equation provides equilibrium positions and characteristic oscillation frequencies of the solitons, which are found to be in good agreement with the eigenfrequencies of the anomalous modes of the system.

  16. Symbolic-computation study of bright solitons in the optical waveguides and Bose-Einstein condensates

    Science.gov (United States)

    Wang, Yun-Po; Tian, Bo; Wang, Yu-Feng; Huang, Zhi-Ruo; Sun, Ya; Cai, Hui-Ping

    2015-06-01

    We investigate solitons in optical waveguides and Bose-Einstein condensates (BECs) governed by a (3+1)-dimensional Gross-Pitaevskii system, which describes the propagation of electromagnetic waves in the optical waveguides and ground-state wave functions of the BECs. We use the symbolic computation and Hirota method to derive analytic bright one- and two-soliton solutions under certain conditions. Soliton amplitude/width amplification and the influence of time-modulated dispersion on the bright-soliton shape are studied via graphic analysis. Through the analysis of bright solitons in optical waveguides and BECs, we find that both the amplitude and the width of bright solitons can become larger during propagation with certain choices of time-modulated dispersion, and that the shape of the bright soliton can also be affected by the time-modulated dispersion; when the time-modulated dispersion is different, we can obtain bright parabolic-like and periodic-type solitons.

  17. Fluorescent biosensor for the detection of hyaluronidase: intensity-based ratiometric sensing and fluorescence lifetime-based sensing using a long lifetime azadioxatriangulenium (ADOTA) fluorophore.

    Science.gov (United States)

    Chib, Rahul; Mummert, Mark; Bora, Ilkay; Laursen, Bo W; Shah, Sunil; Pendry, Robert; Gryczynski, Ignacy; Borejdo, Julian; Gryczynski, Zygmunt; Fudala, Rafal

    2016-05-01

    In this report, we have designed a rapid and sensitive, intensity-based ratiometric sensing as well as lifetime-based sensing probe for the detection of hyaluronidase activity. Hyaluronidase expression is known to be upregulated in various pathological conditions. We have developed a fluorescent probe by heavy labeling of hyaluronic acid with a new orange/red-emitting organic azadioxatriangulenium (ADOTA) fluorophore, which exhibits a long fluorescence lifetime (∼20 ns). The ADOTA fluorophore in water has a peak fluorescence lifetime of ∼20 ns and emission spectra centered at 560 nm. The heavily ADOTA-labeled hyaluronic acid (HA-ADOTA) shows a red shift in the peak emission wavelength (605 nm), a weak fluorescence signal, and a shorter fluorescence lifetime (∼4 ns) due to efficient self-quenching and formation of aggregates. In the presence of hyaluronidase, the brightness and fluorescence lifetime of the sample increase with a blue shift in the peak emission to its original wavelength at 560 nm. The ratio of the fluorescence intensity of the HA-ADOTA probe at 560 and 605 nm can be used as the sensing method for the detection of hyaluronidase. The cleavage of the hyaluronic acid macromolecule reduces the energy migration between ADOTA molecules, as well as the degree of self-quenching and aggregation. This probe can be efficiently used for both intensity-based ratiometric sensing as well as fluorescence lifetime-based sensing of hyaluronidase. The proposed method makes it a rapid and sensitive assay, useful for analyzing levels of hyaluronidase in relevant clinical samples like urine or plasma. Graphical Abstract Scheme showing cleavage of HA-ADOTA probe by hyaluronidase and the change in the emission spectrum of HA-ADOTA probe before and after cleavage by hyaluronidase. PMID:26993308

  18. Strengths and Weaknesses of Recently Engineered Red Fluorescent Proteins Evaluated in Live Cells Using Fluorescence Correlation Spectroscopy

    Science.gov (United States)

    Siegel, Amanda P.; Baird, Michelle A.; Davidson, Michael W.; Day, Richard N.

    2013-01-01

    The scientific community is still looking for a bright, stable red fluorescent protein (FP) as functional as the current best derivatives of green fluorescent protein (GFP). The red FPs exploit the reduced background of cells imaged in the red region of the visible spectrum, but photophysical short comings have limited their use for some spectroscopic approaches. Introduced nearly a decade ago, mCherry remains the most often used red FP for fluorescence correlation spectroscopy (FCS) and other single molecule techniques, despite the advent of many newer red FPs. All red FPs suffer from complex photophysics involving reversible conversions to a dark state (flickering), a property that results in fairly low red FP quantum yields and potential interference with spectroscopic analyses including FCS. The current report describes assays developed to determine the best working conditions for, and to uncover the shortcoming of, four recently engineered red FPs for use in FCS and other diffusion and spectroscopic studies. All five red FPs assayed had potential shortcomings leading to the conclusion that the current best red FP for FCS is still mCherry. The assays developed here aim to enable the rapid evaluation of new red FPs and their smooth adaptation to live cell spectroscopic microscopy and nanoscopy. PMID:24129172

  19. Self-deflection of bright soliton in a separate bright-dark screening soliton pair based on higher-order space charge field

    Institute of Scientific and Technical Information of China (English)

    Zhonghua Hao(郝中华); Jinsong Liu(刘劲松)

    2003-01-01

    Based on the interaction of the separate soliton pair, the self-deflection of the bright screening soliton in a bright-dark pair is studied by taking the higher order space charge field into account. Both numerical and analytical methods are adopted to obtain the result that the higher order of space charge field can enhance the deflection process of the bright soliton and varying the peak intensity of the dark soliton can influence the self-deflection strongly. The expression of the deflection distance with the dark soliton's peak intensity is derived, and some corresponding properties of the self-deflection process are figured out.

  20. Bright-dark vector soliton solutions for the coupled complex short pulse equations in nonlinear optics

    CERN Document Server

    Guo, Bo-Ling

    2016-01-01

    Under investigation in this paper are the coupled complex short pulse equations, which describe the propagation of ultra-short optical pulses in cubic nonlinear media.Through the Hirota method, bright-dark one- and two-soliton solutions are obtained. Interactions between two bright or two dark solitons are verified to be elastic through the asymptotic analysis. With different parameter conditions of the vector bright-dark two solitons, the oblique interactions, bound states of solitons and parallel solitons are analyzed.

  1. Effects of Periodically Inhomogeneous Birefringence on Dark-Bright Vector Soliton Propagation and Interaction

    Institute of Scientific and Technical Information of China (English)

    LI Hong; D. N. Wang

    2007-01-01

    The effects of periodically inhomogeneous birefringence on dark-bright vector soliton propagation and interaction are investigated by the numerical method. The birefringence leads to the submergence of the dark soliton and the disintegration of the bright soliton, and enhances the interaction between the neighbouring solitons. The system performance is determined by the bright soliton because the dark soliton has robust features. Finally, the avoidance and the effective control are introduced, and the controlling mechanism is demonstrated.

  2. Discovery of two new bright magnetic B stars: i Car and Atlas

    OpenAIRE

    Neiner, Coralie; Buysschaert, Bram; Oksala, Mary E.; Blazere, Aurore

    2015-01-01

    The BRITE (BRIght Target Explorer) constellation of nano-satellites performs seismology of bright stars via high precision photometry. In this context, we initiated a high resolution, high signal-to-noise, high sensitivity, spectropolarimetric survey of all stars brighter than V=4. The goal of this survey is to detect new bright magnetic stars and provide prime targets for both detailed magnetic studies and asteroseismology with BRITE. Circularly polarised spectra were acquired with Narval at...

  3. Development of a new leather intermediate: wet-bright with a high dye affinity

    OpenAIRE

    Bacardit Dalmases, Anna; González, Maria; van der Burgh, Stefan; Armengol, Jordi; Ollé Otero, Lluís

    2016-01-01

    In this work we develop a new tanning process (that we call wet-bright) that produces leather free of chromium, aldehydes, aldehyde precursors and organic solvents. Due to the mineral character of the new system, the leather offers a perfect dyeability and high dye affinity, allowing for very bright colors in all leather applications. The leathers offer a perfect dyeability due to the brilliant whiteness of the wet-bright intermediate. This new system consists of the application of Tanfor TTM...

  4. Efficacy of a single sequence of intermittent bright light pulses for delaying circadian phase in humans

    OpenAIRE

    Gronfier, Claude; Wright, Kenneth P.; Kronauer, Richard E.; Jewett, Megan E.; Czeisler, Charles A.

    2004-01-01

    It has been shown in animal studies that exposure to brief pulses of bright light can phase shift the circadian pacemaker, and that the resetting action of light is most efficient during the first minutes of light exposure. In humans, multiple consecutive days of exposure to brief bright light pulses have been shown to phase shift the circadian pacemaker. The aim of the present study was to determine if a single sequence of brief bright light pulses administered during the early biological ni...

  5. On the brightness of diluted photon source in synchrotron light facilities

    Energy Technology Data Exchange (ETDEWEB)

    Ivanyan, M. E-mail: ivanian@asls.candle.am; Martirosyan, Y.; Tsakanov, V

    2004-10-01

    The undulator radiation spectral brightness in storage ring is studied taking into account the effects of the electron beam oscillating trajectory and the beam transverse size variation along the undulator. The modified optimal beta function at the source point to reach maximum brightness is obtained that is in direct relation with the emitted photons wavelength. It is shown that the maximum spectral brightness in long wavelength range is achieved with low beta lattice, while in short wavelength range with larger beta.

  6. Photometric indicators of visual night sky quality derived from all-sky brightness maps

    Science.gov (United States)

    Duriscoe, Dan M.

    2016-09-01

    Wide angle or fisheye cameras provide a high resolution record of artificial sky glow, which results from the scattering of escaped anthropogenic light by the atmosphere, over the sky vault in the moonless nocturnal environment. Analysis of this record yields important indicators of the extent and severity of light pollution. The following indicators were derived through numerical analysis of all-sky brightness maps: zenithal, average all-sky, median, brightest, and darkest sky brightness. In addition, horizontal and vertical illuminance, resulting from sky brightness were computed. A natural reference condition to which the anthropogenic component may be compared is proposed for each indicator, based upon an iterative analysis of a high resolution natural sky model. All-sky brightness data, calibrated in the V band by photometry of standard stars and converted to luminance, from 406 separate data sets were included in an exploratory analysis. Of these, six locations representing a wide range of severity of impact from artificial sky brightness were selected as examples and examined in detail. All-sky average brightness is the most unbiased indicator of impact to the environment, and is more sensitive and accurate in areas of slight to moderate light pollution impact than zenith brightness. Maximum vertical illuminance provides an excellent indicator of impacts to wilderness character, as does measures of the brightest portions of the sky. Zenith brightness, the workhorse of field campaigns, is compared to the other indicators and found to correlate well with horizontal illuminance, especially at relatively bright sites. The median sky brightness describes a brightness threshold for the upper half of the sky, of importance to telescopic optical astronomy. Numeric indicators, in concert with all-sky brightness maps, provide a complete assessment of visual sky quality at a site.

  7. Music for a Brighter World: Brightness Judgment Bias by Musical Emotion

    OpenAIRE

    Joydeep Bhattacharya; Lindsen, Job P.

    2016-01-01

    A prevalent conceptual metaphor is the association of the concepts of good and evil with brightness and darkness, respectively. Music cognition, like metaphor, is possibly embodied, yet no study has addressed the question whether musical emotion can modulate brightness judgment in a metaphor consistent fashion. In three separate experiments, participants judged the brightness of a grey square that was presented after a short excerpt of emotional music. The results of Experiment 1 showed that ...

  8. Detection of the bright band with a vertically pointing k-band radar

    OpenAIRE

    Thomas Pfaff; Alexander Engelbrecht; Jochen Seidel

    2014-01-01

    Quantitative precipitation estimation based on weather radar data suffers from a variety of errors. During stratiform events, a region of enhanced reflectivity, called the bright band, leads to large positive biases in the precipitation estimates when compared with ground measurements. The identification of the bright band is an important step when trying to correct weather radar data for this effect. In this study we investigate three different methods to identify the bright band from profil...

  9. Bright galaxies in the Fornax cluster. Automated galaxy surface photometry: Pt. 7

    International Nuclear Information System (INIS)

    We have determined surface-brightness profiles for all galaxies down to magnitude B = 16 in the central region of the Fornax cluster. Using existing redshift data, we have determined the distributions of surface brightness for both the whole sample and for cluster disc galaxies only. Although both distributions peak at extrapolated central surface brightness ∼ 21.7B mag/arcsec2 (the canonical result), it is shown that they are, in fact, consistent with very broad distributions of disc central surface brightness once selection effects and the effects of bulge contamination of the profile are taken into account. (author)

  10. CHLORINE DIOXIDE BLEACHING OF SODA-ANTHRAQUINONE JUTE PULP TO A VERY HIGH BRIGHTNESS

    OpenAIRE

    M. Sarwar Jahan; Yonghao Ni,; Zhibin He

    2010-01-01

    Bleaching of soda-anthraquinone jute pulp by chlorine dioxide (ClO2) was studied to reach a target brightness of above 88% for the purpose of using less bleaching chemicals. The performance of either chlorine dioxide or peroxide in the final bleaching to boost brightness was also studied. The experimental results revealed that the final brightness depended on ClO2 charge in the Do and D1 stages. The brightness reversion was lower when the final stage brightening was done by peroxide. The use ...

  11. Assessing Photosynthesis by Fluorescence Imaging

    Science.gov (United States)

    Saura, Pedro; Quiles, Maria Jose

    2011-01-01

    This practical paper describes a novel fluorescence imaging experiment to study the three processes of photochemistry, fluorescence and thermal energy dissipation, which compete during the dissipation of excitation energy in photosynthesis. The technique represents a non-invasive tool for revealing and understanding the spatial heterogeneity in…

  12. X-ray Fluorescence Sectioning

    CERN Document Server

    Cong, Wenxiang

    2012-01-01

    In this paper, we propose an x-ray fluorescence imaging system for elemental analysis. The key idea is what we call "x-ray fluorescence sectioning". Specifically, a slit collimator in front of an x-ray tube is used to shape x-rays into a fan-beam to illuminate a planar section of an object. Then, relevant elements such as gold nanoparticles on the fan-beam plane are excited to generate x-ray fluorescence signals. One or more 2D spectral detectors are placed to face the fan-beam plane and directly measure x-ray fluorescence data. Detector elements are so collimated that each element only sees a unique area element on the fan-beam plane and records the x-ray fluorescence signal accordingly. The measured 2D x-ray fluorescence data can be refined in reference to the attenuation characteristics of the object and the divergence of the beam for accurate elemental mapping. This x-ray fluorescence sectioning system promises fast fluorescence tomographic imaging without a complex inverse procedure. The design can be ad...

  13. Fluorescence sensitization of gold-glutathione nanoclusters by aqueous solutions of sodium and potassium ions

    International Nuclear Information System (INIS)

    Gold nanoclusters (Au-NCs) are powerful alternatives to commonly used dyes for use in fluorescent assays and in imaging. This is due to their high brightness and biocompatibility. Glutathione protected gold nanoclusters (Au-NCs-GSH) were used to investigate the effect of sodium and potassium ions (at 0.1 to 1 mM concentrations) on their fluorescence. It was found that addition of these alkali ions does not modify the emission wavelength of AuNCs-GSH, but fluorescence intensity undergoes a gradual increase (by ∼130 %) until a plateau is reached. Fluorescence is particularly enhanced by KSCN. The effect is interpreted in terms of a decrease in the band gap of the AuNCs-GSH that depends on the nature of the anion. The results illustrate the role of anions and monovalent cations commonly used in buffers with respect to the tuning of the fluorescence of AuNCs-GSH. The findings should be taken into account when using AuNCs-GSH in assays based on fluorescence enhancement or quenching. (author)

  14. Selective colorimetric and fluorescent quenching determination of uranyl ion via its complexation with curcumin

    Science.gov (United States)

    Zhu, Jing-Hui; Zhao, Xin; Yang, Jidong; Tan, Yu-Ting; Zhang, Lei; Liu, Shao-Pu; Liu, Zhong-Fang; Hu, Xiao-Li

    2016-04-01

    Under pH 4.0 HAc-NaAc buffer medium, curcumin alone possesses extraordinary weak fluorescence emission. Nevertheless, the introduction of Triton X-100 micelles can largely enhance the fluorescence intensity of curcumin. Uranyl ions can complex with micelles-capped curcumin, along with the slight red shift of curcumin fluorescence (about 1-7 nm), a clear decrement of absorbance (424 nm) and fluorescence (507 nm) intensities, and a distinct color change from bright yellow to orange. The fluorescence decrements (ΔF, 507 nm) are positively correlated to the amount of uranyl ions in the concentration range of 3.7 × 10- 6-1.4 × 10- 5 mol L- 1. The detection limit of this fluorescence quenching methods is 3.7 × 10- 6 mol L- 1, which is nearly 9000 times lower than the maximum allowable level in drinking water proposed by World Health Organization. Good selectivity is achieved because of a majority of co-existing substances (such as Ce4 +, La3 +, and Th4 +) do not affect the detection. The content of uranyl ions in tap water samples was determined by the proposed method with satisfactory results.

  15. Red Fluorescent Line Emission from Hydrogen Molecules in Diffuse Molecular Clouds

    Science.gov (United States)

    Neufeld, David A.; Spaans, Marco

    1996-01-01

    We have modeled the fluorescent pumping of electronic and vibrational emissions of molecular hydrogen (H2) within diffuse molecular clouds that are illuminated by ultraviolet continuum radiation. Fluorescent line intensities are predicted for transitions at ultraviolet, infrared, and red visible wavelengths as functions of the gas density, the visual extinction through the cloud, and the intensity of the incident UV continuum radiation. The observed intensity in each fluorescent transition is roughly proportional to the integrated rate of H2 photodissociation along the line of sight. Although the most luminous fluorescent emissions detectable from ground-based observatories lie at near-infrared wavelengths, we argue that the lower sky brightness at visible wavelengths makes the red fluorescent transitions a particularly sensitive probe. Fabry-Perot spectrographs of the type that have been designed to observe very faint diffuse Ha emissions are soon expected to yield sensitivities that will be adequate to detect H2 vibrational emissions from molecular clouds that are exposed to ultraviolet radiation no stronger than the mean radiation field within the Galaxy. Observations of red H2 fluorescent emission together with cospatial 21 cm H I observations could serve as a valuable probe of the gas density in diffuse molecular clouds.

  16. Role of anion polarizability in fluorescence sensitization of DNA-templated silver nanoclusters

    Science.gov (United States)

    Peng, Jian; Shao, Yong; Liu, Lingling; Zhang, Lihua; Fu, Wensheng; Liu, Hua

    2014-06-01

    Fluorescent silver nanoclusters (Ag NCs) as novel fluorophores have received much attention because of their high brightness, good photostability and widely tunable emissions from the visible to the near-infrared range as a result of their size and existing environment. However, efforts are still needed to find the factors that tune the emission of Ag NCs. In this work, Ag NCs that were size-selectively grown on DNA were used to investigate the effect of the electronic properties of coordinating ligands. Halogen anions were used as the paradigm because of their periodicity in element properties. We found that addition of halogen anions did not alter the emission wavelength of Ag NCs, but the fluorescence intensity showed an initial increase at low concentrations of Cl-, Br- and I- followed by a gradual decrease at high concentrations. No increase in fluorescence was observed for F- at either low or high concentration. Such specific halogen-anion sensitization of the fluorescence of Ag NCs suggests that the binding strength/manner and dipole polarizability of these anions synergistically tune the emission behavior of Ag NCs. Less fluorescence sensitization occurred for the anion having high enough polarizability to form a covalent bond with Ag NCs. The anion polarizability-sensitized fluorescence indicates the role of anion electronic properties in tuning the emission behavior of Ag NCs, which should be seriously considered in designing Ag NC-based sensors and devices.

  17. Green Synthesis of Fluorescent Carbon Dots for Selective Detection of Tartrazine in Food Samples.

    Science.gov (United States)

    Xu, Hua; Yang, Xiupei; Li, Gu; Zhao, Chuan; Liao, Xiangjun

    2015-08-01

    A simple, economical, and green method for the preparation of water-soluble, high-fluorescent carbon quantum dots (C-dots) has been developed via hydrothermal process using aloe as a carbon source. The synthesized C-dots were characterized by atomic force microscope (AFM), transmission electron microscopy (TEM), fluorescence spectrophotometer, UV-vis absorption spectra as well as Fourier transform infrared spectroscopy (FTIR). The results reveal that the as-prepared C-dots were spherical shape with an average diameter of 5 nm and emit bright yellow photoluminescence (PL) with a quantum yield of approximately 10.37%. The surface of the C-dots was rich in hydroxyl groups and presented various merits including high fluorescent quantum yield, excellent photostability, low toxicity and satisfactory solubility. Additionally, we found that one of the widely used synthetic food colorants, tartrazine, could result in a strong fluorescence quenching of the C-dots through a static quenching process. The decrease of fluorescence intensity made it possible to determine tartrazine in the linear range extending from 0.25 to 32.50 μM, This observation was further successfully applied for the determination of tartrazine in food samples collected from local markets, suggesting its great potential toward food routine analysis. Results from our study may shed light on the production of fluorescent and biocompatible nanocarbons due to our simple and environmental benign strategy to synthesize C-dots in which aloe was used as a carbon source. PMID:26154603

  18. Endoscopic fluorescence imaging for early assessment of anastomotic recurrence of Crohn's disease

    Science.gov (United States)

    Mordon, Serge R.; Maunoury, Vincent; Geboes, K.; Klein, Olivier; Desreumaux, P.; Debaert, A.; Colombel, Jean-Frederic

    1999-02-01

    Crohn's disease is an inflammatory bowel disease of unknown etiology. The mechanism of the initial mucosal alterations is still unclear: ulcerations overlying lymphoid follicles and/or vasculitis have been proposed as the early lesions. We have developed a new and original method combining endoscopy of fluorescence angiography for identifying the early pathological lesions, occurring in the neo-terminal ileum after right ileocolonic resection. The patient population consisted of 10 subjects enrolled in a prospective protocol of endoscopic follow-up at 3 and 12 months after surgery. Fluorescence imaging showed small spots giving a bright fluorescence distributed singly in mucosa which appeared normal in routine endoscopy. Histopathological examination demonstrated that the fluorescence of small spots originated from small, usually superficial, erosive lesions. In several cases, these erosive lesions occurred over lymphoid follicles. Endoscopic fluorescence imaging provides a suitable means of investigating the initial aspect of the Crohn's disease process in displaying some correlative findings between fluorescent aspects and early pathological mucosal alterations.

  19. Optical Properties of Fluorescent Dyes

    Institute of Scientific and Technical Information of China (English)

    李戎; 陈东辉

    2001-01-01

    Fluorescent dyes have been widely used these years.Because of the special optical performance, conventional CCM systems seem to be unable to predict the recipes of fabrics dyed with fluorescent dyes. In order to enhance the functions of CCM systems, the optical properties of fluorescent dyes in their absorption region were investigated. It has been found that there was a fixed maximum absorption wavelength for each fluorescent dyes whatever its concentration is. Both absorption region and maximum absorption wavelength of the dyes in solution are the same to those in fabric, and that the absorption is directly proportional to the concentration of the dye. So the optical properties obtained in solutions cna be applied for describing the optics performance of fluorescent dyes in fabrics.

  20. Time-resolved fluorescence spectroscopy

    International Nuclear Information System (INIS)

    This article addresses the evolution in time of light emitted by a molecular system after a brief photo-excitation. The authors first describe fluorescence from a photo-physical point of view and discuss the characterization of the excited state. Then, they explain some basic notions related to fluorescence characterization (lifetime and decays, quantum efficiency, so on). They present the different experimental methods and techniques currently used to study time-resolved fluorescence. They discuss basic notions of time resolution and spectral reconstruction. They briefly present some conventional methods: intensified Ccd cameras, photo-multipliers and photodiodes associated with a fast oscilloscope, and phase modulation. Other methods and techniques are more precisely presented: time-correlated single photon counting (principle, examples, and fluorescence lifetime imagery), streak camera (principle, examples), and optical methods like the Kerr optical effect (principle and examples) and fluorescence up-conversion (principle and theoretical considerations, examples of application)