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Sample records for 1-d upconversion submicrocrystals

  1. One-pot hydrothermal synthesis of lanthanide ions doped one-dimensional upconversion submicrocrystals and their potential application in vivo CT imaging.

    PubMed

    Gao, Guo; Zhang, Chunlei; Zhou, Zhijun; Zhang, Xin; Ma, Jiebing; Li, Chao; Jin, Weilin; Cui, Daxiang

    2013-01-01

    Multi-functional rare-earth Yb(3+) and Ln(3+) (Ln = Er, Tm and Ho) ions doped one-dimensional (1-D) upconversion submicrocrystals (NaYF(4) and NaGdF(4)) possessing upconversion luminescence, biocompatibility and magnetic properties have been synthesized by a one-pot hydrothermal method. Rare-earth Yb(3+) and Ln(3+) ions doped NaYF(4) microrods (~1 μm in diameter, 3-5 μm in length) exhibit porous properties, and the average pore sizes are ~28.2 nm. They show paramagnetism in the magnetic range of -60 to -2 kOe and 2 to 60 kOe at 300 K, and exhibit near superparamagnetic behaviour at the magnetic range of -2 to 2 kOe. Saturation magnetization was ~12.1 emu g(-1) at 2 K. The Yb(3+) and Ln(3+) ions doped NaGdF(4) submicrocrystals (~100 nm in diameter, 200-300 nm in length) show paramagnetism at 300 K, and exhibit superparamagnetic behaviour with a saturation magnetization of 129.2 emu g(-1) at 2 K. The magnetic properties of Yb(3+) and Ln(3+) ions doped 1-D upconversion submicrocrystals indicate they can be used for drug targeting under a magnetic field. Their unique upconversion emission (green for Yb(3+)/Er(3+) and blue for Yb(3+)/Tm(3+)) under 980 nm laser excitation indicate that they could be used for specific luminescent immunolabeling and imaging. MTT assays reveal that 1-D upconversion submicrocrystals have satisfactory bio-affinity, where the viability keeps in good state even at a concentration of 500 μg mL(-1), which is much higher than the concentration usually used in cell labelling. Luminescent microscopy images show that the morphologies of the cytoskeleton and cell nucleus are well maintained after incubating different concentrations of 1-D upconversion submicrocrystals. After injecting upconversion submicrocrystals into the mice (tumor sites or back normal tissue), a clearly distinguished CT signal was observed, indicating the synthesized 1-D submicrocrystals are effective for CT imaging in vivo.

  2. Morphology control and multicolor up-conversion luminescence of GdOF:Yb3+/Er3+, Tm3+, Ho3+ nano/submicrocrystals.

    PubMed

    Zhang, Yang; Li, Xuejiao; Kang, Xiaojiao; Hou, Zhiyao; Lin, Jun

    2014-06-14

    In this paper, well defined GdOF:Yb(3+)/Er(3+), Tm(3+), Ho(3+) nano/submicrocrystals with multiform morphologies were prepared via the urea-based precipitation method without using any surfactants. The morphologies of the GdOF products, including spindles and spheres with different sizes (30-550 nm), could be easily modulated by changing the fluorine sources, and the possible formation mechanism has been presented. XRD, FT-IR, SEM, TEM, as well as up-conversion (UC) photoluminescence spectra were used to characterize the prepared samples. Under 980 nm NIR excitation, the relative emission intensities and emission colors of Yb(3+)/Er(3+), Yb(3+)/Tm(3+) and Yb(3+)/Ho(3+) doped GdOF could be precisely adjusted over a wide range by tuning the Yb(3+) doping concentration. The strategies for color tuning of UC emission proposed in the current system may be helpful to achieve efficient multicolor luminescence under 980 nm laser excitation. In addition, the corresponding UC mechanisms in the co-doping GdOF systems were analyzed in detail based on the emission spectra and the plot of luminescence intensity to pump power.

  3. Comprehensive analysis of photonic effects on up-conversion of β-NaYF4:Er3+ nanoparticles in an organic-inorganic hybrid 1D photonic crystal

    NASA Astrophysics Data System (ADS)

    Hofmann, C. L. M.; Fischer, S.; Reitz, C.; Richards, B. S.; Goldschmidt, J. C.

    2016-04-01

    Upconversion (UC) presents a possibility to exploit sub-bandgap photons for current generation in solar cells by creating one high-energy photon out of at least two lower-energy photons. Photonic structures can enhance UC by two effects: a locally increased irradiance and a modified local density of photon states (LDOS). Bragg stacks are promising photonic structures for this application, because they are straightforward to optimize and overall absorption can be increased by adding more layers. In this work, we present a comprehensive simulation-based analysis of the photonic effects of a Bragg stack on UC luminescence. The investigated organic-inorganic hybrid Bragg stack consists of alternating layers of Poly(methylmethacrylate) (PMMA), containing purpose-built β-NaYF4:25% Er3+ core-shell nanoparticles and titanium dioxide (TiO2). From optical characterization of single thin layers, input parameters for simulations of the photonic effects are generated. The local irradiance enhancement and modulated LDOS are first simulated separately. Subsequently they are coupled in a rate equation model of the upconversion dynamics. Using the integrated model, UC luminescence is maximized by adapting the Bragg stack design. For a Bragg stack of only 5 bilayers, UC luminescence is enhanced by a factor of 3.8 at an incident irradiance of 2000 W/m2. Our results identify the Bragg stack as promising for enhancing UC, especially in the low-irradiance regime, relevant for the application in photovoltaics. Therefore, we experimentally realized optimized Bragg stack designs. The PMMA layers, containing UC nanoparticles, are produced via spin-coating from a toluene based solution. The TiO2 layers are produced by atomic layer deposition from molecular precursors. The reflectance measurements show that the realized Bragg stacks are in good agreement with predictions from simulation.

  4. Infrared upconversion for astronomy

    NASA Technical Reports Server (NTRS)

    Boyd, R. W.

    1977-01-01

    The basic theory of upconversion is presented, along with a brief historical summary of upconversion techniques. Upconverters were used in astronomical studies, but have met with only modest success. Upconversion will become a useful detection method for astronomy only if substantial but perhaps forseeable, improvements can be realized.

  5. Materials Integrating Photochemical Upconversion.

    PubMed

    McCusker, Catherine E; Castellano, Felix N

    2016-04-01

    This review features recent experimental work focused on the preparation and characterization of materials that integrate photochemical upconversion derived from sensitized triplet-triplet annihilation, resulting in the conversion of low energy photons to higher energy light, thereby enabling numerous wavelength-shifting applications. Recent topical developments in upconversion include encapsulating or rigidifying fluid solutions to give them mechanical strength, adapting inert host materials to enable upconversion, and using photoactive materials that incorporate the sensitizer and/or the acceptor. The driving force behind translating photochemical upconversion from solution into hard and soft materials is the incorporation of upconversion into devices and other applications. At present, some of the most promising applications of upconversion materials include imaging and fluorescence microscopy, photoelectrochemical devices, water disinfection, and solar cell enhancement.

  6. Materials Integrating Photochemical Upconversion.

    PubMed

    McCusker, Catherine E; Castellano, Felix N

    2016-04-01

    This review features recent experimental work focused on the preparation and characterization of materials that integrate photochemical upconversion derived from sensitized triplet-triplet annihilation, resulting in the conversion of low energy photons to higher energy light, thereby enabling numerous wavelength-shifting applications. Recent topical developments in upconversion include encapsulating or rigidifying fluid solutions to give them mechanical strength, adapting inert host materials to enable upconversion, and using photoactive materials that incorporate the sensitizer and/or the acceptor. The driving force behind translating photochemical upconversion from solution into hard and soft materials is the incorporation of upconversion into devices and other applications. At present, some of the most promising applications of upconversion materials include imaging and fluorescence microscopy, photoelectrochemical devices, water disinfection, and solar cell enhancement. PMID:27573144

  7. Upconversion in solar cells

    PubMed Central

    2013-01-01

    The possibility to tune chemical and physical properties in nanosized materials has a strong impact on a variety of technologies, including photovoltaics. One of the prominent research areas of nanomaterials for photovoltaics involves spectral conversion. Modification of the spectrum requires down- and/or upconversion or downshifting of the spectrum, meaning that the energy of photons is modified to either lower (down) or higher (up) energy. Nanostructures such as quantum dots, luminescent dye molecules, and lanthanide-doped glasses are capable of absorbing photons at a certain wavelength and emitting photons at a different (shorter or longer) wavelength. We will discuss upconversion by lanthanide compounds in various host materials and will further demonstrate upconversion to work for thin-film silicon solar cells. PMID:23413889

  8. Upconversion in solar cells.

    PubMed

    van Sark, Wilfried Gjhm; de Wild, Jessica; Rath, Jatin K; Meijerink, Andries; Schropp, Ruud Ei

    2013-02-15

    The possibility to tune chemical and physical properties in nanosized materials has a strong impact on a variety of technologies, including photovoltaics. One of the prominent research areas of nanomaterials for photovoltaics involves spectral conversion. Modification of the spectrum requires down- and/or upconversion or downshifting of the spectrum, meaning that the energy of photons is modified to either lower (down) or higher (up) energy. Nanostructures such as quantum dots, luminescent dye molecules, and lanthanide-doped glasses are capable of absorbing photons at a certain wavelength and emitting photons at a different (shorter or longer) wavelength. We will discuss upconversion by lanthanide compounds in various host materials and will further demonstrate upconversion to work for thin-film silicon solar cells.

  9. Plasmon enhancement of luminescence upconversion.

    PubMed

    Park, Wounjhang; Lu, Dawei; Ahn, Sungmo

    2015-05-21

    Frequency conversion has always been an important topic in optics. Nonlinear optics has traditionally focused on frequency conversion based on nonlinear susceptibility but with the recent development of upconversion nanomaterials, luminescence upconversion has begun to receive renewed attention. While upconversion nanomaterials open doors to a wide range of new opportunities, they remain too inefficient for most applications. Incorporating plasmonic nanostructures provides a promising pathway to highly efficient upconversion. Naturally, a plethora of theoretical and experimental studies have been published in recent years, reporting enhancements up to several hundred. It is however difficult to make meaningful comparisons since the plasmonic fields are highly sensitive to the local geometry and excitation condition. Also, many luminescence upconversion processes involve multiple steps via different physical mechanisms and the overall output is often determined by a delicate interplay among them. This review is aimed at offering a comprehensive framework for plasmon enhanced luminescence upconversion. We first present quantum electrodynamics descriptions for all the processes involved in luminescence upconversion, which include absorption, emission, energy transfer and nonradiative transitions. We then present a bird's eye view of published works on plasmon enhanced upconversion, followed by more detailed discussion on comparable classes of nanostructures, the effects of spacer layers and local heating, and the dynamics of the plasmon enhanced upconversion process. Plasmon enhanced upconversion is a challenging and exciting field from the fundamental scientific perspective and also from technological standpoints. It offers an excellent system to study how optical processes are affected by the local photonic environment. This type of research is particularly timely as the plasmonics is placing heavier emphasis on nonlinearity. At the same time, efficient upconversion

  10. 1D nanocrystals with precisely controlled dimensions, compositions, and architectures

    NASA Astrophysics Data System (ADS)

    Pang, Xinchang; He, Yanjie; Jung, Jaehan; Lin, Zhiqun

    2016-09-01

    The ability to synthesize a diverse spectrum of one-dimensional (1D) nanocrystals presents an enticing prospect for exploring nanoscale size- and shape-dependent properties. Here we report a general strategy to craft a variety of plain nanorods, core-shell nanorods, and nanotubes with precisely controlled dimensions and compositions by capitalizing on functional bottlebrush-like block copolymers with well-defined structures and narrow molecular weight distributions as nanoreactors. These cylindrical unimolecular nanoreactors enable a high degree of control over the size, shape, architecture, surface chemistry, and properties of 1D nanocrystals. We demonstrate the synthesis of metallic, ferroelectric, upconversion, semiconducting, and thermoelectric 1D nanocrystals, among others, as well as combinations thereof.

  11. 1D nanocrystals with precisely controlled dimensions, compositions, and architectures.

    PubMed

    Pang, Xinchang; He, Yanjie; Jung, Jaehan; Lin, Zhiqun

    2016-09-16

    The ability to synthesize a diverse spectrum of one-dimensional (1D) nanocrystals presents an enticing prospect for exploring nanoscale size- and shape-dependent properties. Here we report a general strategy to craft a variety of plain nanorods, core-shell nanorods, and nanotubes with precisely controlled dimensions and compositions by capitalizing on functional bottlebrush-like block copolymers with well-defined structures and narrow molecular weight distributions as nanoreactors. These cylindrical unimolecular nanoreactors enable a high degree of control over the size, shape, architecture, surface chemistry, and properties of 1D nanocrystals. We demonstrate the synthesis of metallic, ferroelectric, upconversion, semiconducting, and thermoelectric 1D nanocrystals, among others, as well as combinations thereof. PMID:27634531

  12. Visible upconversion emission of Pr3+ doped gadolinium gallium garnet nanocrystals.

    PubMed

    Naccache, R; Vetrone, F; Boyer, J C; Capobianco, J A; Speghini, A; Bettinelli, M

    2004-11-01

    The luminescence properties of a Pr3+-doped gadolinium gallium garnet (GGG, Gd3Ga5O12) nanocrystalline host were investigated. Dominant blue/green emission was observed emanating from the 3P0 --> 3H4 transition after excitation using a wavelength of 457.9 nm. Continuous wave excitation into the 1D2 level of the Pr3+ ion at 606.9 nm transition produced blue upconversion luminescence spectra, ascribed to emission from the 3P1 --> 3H4 and 3P0 --> 3H4 transitions. The increase in the decay times of the observed transitions following excitation with 606.9 nm is indicative of the dominance of an energy transfer upconversion (ETU) mechanism relative to excited state absorption (ESA). Furthermore, blue, green and red upconversion emission was observed from the 3P0, 3P1 and 1D2 states following excitation into the 1G4 energy level with 980 nm. No change in the decay times of the emitting states was observed following excitation with a wavelength of 980 or 457.9 nm; hence, upconversion was determined to primarily occur through ESA. The luminescence properties of the nanocrystals are compared to a single crystal of GGG:Pr3+ (bulk) with an identical Pr3+ concentration (1%).

  13. Photon upconversion with directed emission.

    PubMed

    Börjesson, K; Rudquist, P; Gray, V; Moth-Poulsen, K

    2016-01-01

    Photon upconversion has the potential to increase the efficiency of single bandgap solar cells beyond the Shockley Queisser limit. Efficient light management is an important point in this context. Here we demonstrate that the direction of upconverted emission can be controlled in a reversible way, by embedding anthracene derivatives together with palladium porphyrin in a liquid crystalline matrix. The system is employed in a triplet-triplet annihilation photon upconversion scheme demonstrating controlled switching of directional anti Stokes emission. Using this approach an emission ratio of 0.37 between the axial and longitudinal emission directions and a directivity of 1.52 is achieved, reasonably close to the theoretical maximal value of 2 obtained from a perfectly oriented sample. The system can be switched for multiple cycles without any visible degradation and the speed of switching is only limited by the intrinsic rate of alignment of the liquid crystalline matrix. PMID:27573539

  14. Photon upconversion with directed emission

    PubMed Central

    Börjesson, K.; Rudquist, P.; Gray, V.; Moth-Poulsen, K.

    2016-01-01

    Photon upconversion has the potential to increase the efficiency of single bandgap solar cells beyond the Shockley Queisser limit. Efficient light management is an important point in this context. Here we demonstrate that the direction of upconverted emission can be controlled in a reversible way, by embedding anthracene derivatives together with palladium porphyrin in a liquid crystalline matrix. The system is employed in a triplet-triplet annihilation photon upconversion scheme demonstrating controlled switching of directional anti Stokes emission. Using this approach an emission ratio of 0.37 between the axial and longitudinal emission directions and a directivity of 1.52 is achieved, reasonably close to the theoretical maximal value of 2 obtained from a perfectly oriented sample. The system can be switched for multiple cycles without any visible degradation and the speed of switching is only limited by the intrinsic rate of alignment of the liquid crystalline matrix. PMID:27573539

  15. Photon upconversion with directed emission

    NASA Astrophysics Data System (ADS)

    Börjesson, K.; Rudquist, P.; Gray, V.; Moth-Poulsen, K.

    2016-08-01

    Photon upconversion has the potential to increase the efficiency of single bandgap solar cells beyond the Shockley Queisser limit. Efficient light management is an important point in this context. Here we demonstrate that the direction of upconverted emission can be controlled in a reversible way, by embedding anthracene derivatives together with palladium porphyrin in a liquid crystalline matrix. The system is employed in a triplet-triplet annihilation photon upconversion scheme demonstrating controlled switching of directional anti Stokes emission. Using this approach an emission ratio of 0.37 between the axial and longitudinal emission directions and a directivity of 1.52 is achieved, reasonably close to the theoretical maximal value of 2 obtained from a perfectly oriented sample. The system can be switched for multiple cycles without any visible degradation and the speed of switching is only limited by the intrinsic rate of alignment of the liquid crystalline matrix.

  16. WDM up-conversion employing frequency quadrupling in optical modulator.

    PubMed

    Shih, Po-Tsung; Lin, Chun-Ting; Jiang, Wen-Jr; Chen, Jason Jyehong; Huang, Han-Sheng; Chen, Yu-Hung; Peng, Peng-Chun; Chi, Sien

    2009-02-01

    This work presents an optical up-conversion system with frequency quadrupling for wavelength-division-multiplexing (WDM) communication systems using a dual-parallel Mach-Zehnder modulator without optical filtering. Four-channel 1.25-Gb/s wired fiber-to-the-x (FTTx) and wireless radio-over-fiber (RoF) signals are generated and transmitted simultaneously. Moreover, the decline in receiver sensitivities due to Mach-Zehnder modulator bias drifts is also investigated. Receiver power penalties of the 20-GHz up-converted WDM signals and baseband (BB) FTTx signals are less than 1 dB when bias deviation voltage is less the 20% of the half-wave voltage. After transmission over a 50-km SSMF, the receiver power penalties of both the BB and 20-GHz RF OOK signals are less than 1 dB. Notably, 60-GHz optical up-conversion can be achieved using 15-GHz radio frequency (RF) components and equipment. PMID:19189002

  17. Infrared Signal Detection by Upconversion Technique

    NASA Technical Reports Server (NTRS)

    Wong, Teh-Hwa; Yu, Jirong; Bai, Yingxin; Johnson, William E.

    2014-01-01

    We demonstrated up-conversion assisted detection of a 2.05-micron signal by using a bulk periodically poled Lithium niobate crystal. The 94% intrinsic up-conversion efficiency and 22.58% overall detection efficiency at pW level of 2.05-micron was achieved.

  18. Photon upconversion in core-shell nanoparticles.

    PubMed

    Chen, Xian; Peng, Denfeng; Ju, Qiang; Wang, Feng

    2015-03-21

    Photon upconversion generally results from a series of successive electronic transitions within complex energy levels of lanthanide ions that are embedded in the lattice of a crystalline solid. In conventional lanthanide-doped upconversion nanoparticles, the dopant ions homogeneously distributed in the host lattice are readily accessible to surface quenchers and lose their excitation energy, giving rise to weak and susceptible emissions. Therefore, present studies on upconversion are mainly focused on core-shell nanoparticles comprising spatially confined dopant ions. By doping upconverting lanthanide ions in the interior of a core-shell nanoparticle, the upconversion emission can be substantially enhanced, and the optical integrity of the nanoparticles can be largely preserved. Optically active shells are also frequently employed to impart multiple functionalities to upconversion nanoparticles. Intriguingly, the core-shell design introduces the possibility of constructing novel upconversion nanoparticles by exploiting the energy exchange interactions across the core-shell interface. In this tutorial review, we highlight recent advances in the development of upconversion core-shell nanoparticles, with particular emphasis on the emerging strategies for regulating the interplay of dopant interactions through core-shell nanostructural engineering that leads to unprecedented upconversion properties. The improved control over photon energy conversion will open up new opportunities for biological and energy applications. PMID:25058157

  19. Blue-green upconversion laser

    DOEpatents

    Nguyen, Dinh C.; Faulkner, George E.

    1990-01-01

    A blue-green laser (450-550 nm) uses a host crystal doped with Tm.sup.3+. The Tm.sup.+ is excited through upconversion by a red pumping laser and an IR pumping laser to a state which transitions to a relatively lower energy level through emissions in the blue-green band, e.g., 450.20 nm at 75 K. The exciting laser may be tunable dye lasers or may be solid-state semiconductor laser, e.g., GaAlAs and InGaAlP.

  20. Blue-green upconversion laser

    DOEpatents

    Nguyen, D.C.; Faulkner, G.E.

    1990-08-14

    A blue-green laser (450--550 nm) uses a host crystal doped with Tm[sup 3+]. The Tm[sup 3+] is excited through upconversion by a red pumping laser and an IR pumping laser to a state which transitions to a relatively lower energy level through emissions in the blue-green band, e.g., 450.20 nm at 75 K. The exciting laser may be tunable dye lasers or may be solid-state semiconductor laser, e.g., GaAlAs and InGaAlP. 3 figs.

  1. Controlling upconversion nanocrystals for emerging applications

    NASA Astrophysics Data System (ADS)

    Zhou, Bo; Shi, Bingyang; Jin, Dayong; Liu, Xiaogang

    2015-11-01

    Lanthanide-doped upconversion nanocrystals enable anti-Stokes emission with pump intensities several orders of magnitude lower than required by conventional nonlinear optical techniques. Their exceptional properties, namely large anti-Stokes shifts, sharp emission spectra and long excited-state lifetimes, have led to a diversity of applications. Here, we review upconversion nanocrystals from the perspective of fundamental concepts and examine the technical challenges in relation to emission colour tuning and luminescence enhancement. In particular, we highlight the advances in functionalization strategies that enable the broad utility of upconversion nanocrystals for multimodal imaging, cancer therapy, volumetric displays and photonics.

  2. Sensitive Infrared Signal Detection by Upconversion Technique

    NASA Technical Reports Server (NTRS)

    Wong, Teh-Hwa; Yu, Jirong; Bai, Yingxin; Johnson, William; Chen, Songsheng; Petros, Mulugeta; Singh, Upendra N.

    2014-01-01

    We demonstrated upconversion assisted detection of a 2.05-micron signal by sum frequency generation to generate a 700-nm light using a bulk periodically poled lithium niobate crystal. The achieved 94% intrinsic upconversion efficiency and 22.58% overall detection efficiency at a pW level of 2.05 micron pave the path to detect extremely weak infrared (IR) signals for remote sensing applications.

  3. DNA-mediated excitonic upconversion FRET switching

    NASA Astrophysics Data System (ADS)

    Kellis, Donald L.; Rehn, Sarah M.; Cannon, Brittany L.; Davis, Paul H.; Graugnard, Elton; Lee, Jeunghoon; Yurke, Bernard; Knowlton, William B.

    2015-11-01

    Excitonics is a rapidly expanding field of nanophotonics in which the harvesting of photons, ensuing creation and transport of excitons via Förster resonant energy transfer (FRET), and subsequent charge separation or photon emission has led to the demonstration of excitonic wires, switches, Boolean logic and light harvesting antennas for many applications. FRET funnels excitons down an energy gradient resulting in energy loss with each step along the pathway. Conversely, excitonic energy upconversion via upconversion nanoparticles (UCNPs), although currently inefficient, serves as an energy ratchet to boost the exciton energy. Although FRET-based upconversion has been demonstrated, it suffers from low FRET efficiency and lacks the ability to modulate the FRET. We have engineered an upconversion FRET-based switch by combining lanthanide-doped UCNPs and fluorophores that demonstrates excitonic energy upconversion by nearly a factor of 2, an excited state donor to acceptor FRET efficiency of nearly 25%, and an acceptor fluorophore quantum efficiency that is close to unity. These findings offer a promising path for energy upconversion in nanophotonic applications including artificial light harvesting, excitonic circuits, photovoltaics, nanomedicine, and optoelectronics.

  4. Enhanced UV upconversion emission using plasmonic nanocavities.

    PubMed

    El Halawany, Ahmed; He, Sha; Hodaei, Hossein; Bakry, Ahmed; Razvi, Mir A N; Alshahrie, Ahmed; Johnson, Noah J J; Christodoulides, Demetrios N; Almutairi, Adah; Khajavikhan, Mercedeh

    2016-06-27

    Upconversion of near infrared (NIR) into ultraviolet (UV) radiation could lead to a number of applications in bio-imaging, diagnostics and drug delivery. However, for bare nanoparticles, the conversion efficiency is extremely low. In this work, we experimentally demonstrate strongly enhanced upconversion emission from an ensemble of β-NaYF4:Gd3+/Yb3+/Tm3+ @NaLuF4 core-shell nanoparticles trapped in judiciously designed plasmonic nanocavities. In doing so, different metal platforms and nanostructures are systematically investigated. Our results indicate that using a cross-shape silver nanocavity, a record high enhancement of 170-fold can be obtained in the UV band centered at a wavelength of 345 nm. The observed upconversion efficiency improvement may be attributed to the increased absorption at NIR, the tailored photonic local density of states, and the light out-coupling characteristics of the cavity. PMID:27410563

  5. Enhancement of the short wavelength upconversion emission in inverse opal photonic crystals.

    PubMed

    Wu, Hangjun; Zhu, Jialun; Yang, Zhengwen; Yan, Dong; Wang, Rongfei; Qiu, Jianbei; Song, Zhiguo; Yu, Xue; Yang, Yong; Zhou, Dacheng; Yin, Zhaoyi

    2014-05-01

    Upconversion luminescence properties of Yb-Tb codoped Bi4Ti3O12 inverse opals have been investigated. The results show that the upconversion emission can be modulated by the photonic band gap. More significantly, in the upconversion inverse opals, the excited-state absorption of Tb3+ is greatly enhanced by the suppression of upconversion spontaneous emissions of the intermediate excited state, and thus the short wavelength upconversion emission from Tb3+ is considerably improved. We believe that the present work will be valuable for not only the foundational study of upconversion emission modifications but also new optical devices in upconversion displays and short wavelength upconversion lasers. PMID:24734648

  6. Photon upconversion with hot carriers in plasmonic systems

    SciTech Connect

    Naik, Gururaj V.; Dionne, Jennifer A.

    2015-09-28

    We propose a scheme of photon upconversion based on harnessing the energy of plasmonic hot carriers. Low-energy photons excite hot electrons and hot holes in a plasmonic nanoparticle, which are then injected into an adjacent semiconductor quantum well where they radiatively recombine to emit a photon of higher energy. We theoretically study the proposed upconversion scheme using Fermi-liquid theory and determine the internal quantum efficiency of upconversion to be as high as 25% in 5 nm silver nanocubes. This upconversion scheme is linear in its operation, does not require coherent illumination, offers spectral tunability, and is more efficient than conventional upconverters.

  7. LOW POWER UPCONVERSION FOR SOLAR FUELS PHOTOCHEMISTRY

    SciTech Connect

    Castellano, Felix N.

    2013-08-05

    Earth abundant copper(I) diimine complexes represent a renewable and economically feasible alternative to commonly used heavy metal containing chromophores. In the metal-to-ligand charge transfer (MLCT) excited state, copper(I) diimine complexes typically undergo a significant structural rearrangement, leading to molecules with large Stokes shifts and very short excited state lifetimes, thereby limiting their usefulness as sensitizers in bimolecular electron and triplet energy transfer reactions. Strategically placed bulky substituents on the coordinating phenanthroline ligands have proven useful in restricting the transiently produced excited state Jahn-Teller distortion, leading to longer-lived excited states. By combining bulky sec-butyl groups in the 2- and 9- positions with methyl groups in the 3-,4-, 7-, and 8- positions, a remarkably long-lived (2.8 μs in DCM) copper(I) bis-phenanthroline complex, [Cu(dsbtmp)2]+, has been synthesized and characterized. Unlike other copper(I) diimine complexes, [Cu(dsbtmp)2]+ also retains a μs lifetime in coordinating solvents such as acetonitrile and water as a result of the cooperative sterics inherent in the molecular design. Preliminary results on the use of this complex in hydrogen-forming homogeneous photocatalysis is presented. Photon upconversion based on sensitized triplet-triplet annihilation (TTA) represents a photochemical means to generate high-energy photons (or high-energy chemical products) from low-energy excitation, having potential applications in solar energy conversion and solar fuels producing devices. For the first time, synthetically facile and earth abundant Cu(I) MLCT sensitizers have been successfully incorporated into two distinct photochemical upconversion schemes, affording both red-to-green and orange-to-blue wavelength conversions. Preliminary results on aqueous-based photochemical upconversion as well as intramolecular Sn(IV) porphyrins containing axially coordinated aromatic hydrocarbon

  8. Hexamodal imaging with porphyrin-phospholipid-coated upconversion nanoparticles.

    PubMed

    Rieffel, James; Chen, Feng; Kim, Jeesu; Chen, Guanying; Shao, Wei; Shao, Shuai; Chitgupi, Upendra; Hernandez, Reinier; Graves, Stephen A; Nickles, Robert J; Prasad, Paras N; Kim, Chulhong; Cai, Weibo; Lovell, Jonathan F

    2015-03-11

    Hexamodal imaging using simple nanoparticles is demonstrated. Porphyrin-phospholipids are used to coat upconversion nanoparticles in order to generate a new biocompatible material. The nanoparticles are characterized in vitro and in vivo for imaging via fluorescence, upconversion, positron emission tomography, computed tomography, Cerenkov luminescence, and photoacoustic tomography.

  9. Tuning upconversion through energy migration in core-shell nanoparticles.

    PubMed

    Wang, Feng; Deng, Renren; Wang, Juan; Wang, Qingxiao; Han, Yu; Zhu, Haomiao; Chen, Xueyuan; Liu, Xiaogang

    2011-10-23

    Photon upconversion is promising for applications such as biological imaging, data storage or solar cells. Here, we have investigated upconversion processes in a broad range of gadolinium-based nanoparticles of varying composition. We show that by rational design of a core-shell structure with a set of lanthanide ions incorporated into separated layers at precisely defined concentrations, efficient upconversion emission can be realized through gadolinium sublattice-mediated energy migration for a wide range of lanthanide activators without long-lived intermediary energy states. Furthermore, the use of the core-shell structure allows the elimination of deleterious cross-relaxation. This effect enables fine-tuning of upconversion emission through trapping of the migrating energy by the activators. Indeed, the findings described here suggest a general approach to constructing a new class of luminescent materials with tunable upconversion emissions by controlled manipulation of energy transfer within a nanoscopic region.

  10. Non-collinear upconversion of infrared light.

    PubMed

    Pedersen, Christian; Hu, Qi; Høgstedt, Lasse; Tidemand-Lichtenberg, Peter; Dam, Jeppe Seidelin

    2014-11-17

    Two dimensional mid-infrared upconversion imaging provides unique spectral and spatial information showing good potential for mid-infrared spectroscopy and hyperspectral imaging. However, to extract spectral or spatial information from the upconverted images an elaborate model is needed, which includes non-collinear interaction. We derive here a general theory providing the far field of the upconverted light when two arbitrary fields interact inside a nonlinear crystal. Theoretical predictions are experimentally verified for incoherent radiation and subsequently applied to previously published data with good agreement.

  11. Hybrid upconversion nanomaterials for optogenetic neuronal control

    NASA Astrophysics Data System (ADS)

    Shah, Shreyas; Liu, Jing-Jing; Pasquale, Nicholas; Lai, Jinping; McGowan, Heather; Pang, Zhiping P.; Lee, Ki-Bum

    2015-10-01

    Nanotechnology-based approaches offer the chemical control required to develop precision tools suitable for applications in neuroscience. We report a novel approach employing hybrid upconversion nanomaterials, combined with the photoresponsive ion channel channelrhodopsin-2 (ChR2), to achieve near-infrared light (NIR)-mediated optogenetic control of neuronal activity. Current optogenetic methodologies rely on using visible light (e.g. 470 nm blue light), which tends to exhibit high scattering and low tissue penetration, to activate ChR2. In contrast, our approach enables the use of 980 nm NIR light, which addresses the short-comings of visible light as an excitation source. This was facilitated by embedding upconversion nanomaterials, which can convert NIR light to blue luminescence, into polymeric scaffolds. These hybrid nanomaterial scaffolds allowed for NIR-mediated neuronal stimulation, with comparable efficiency as that of 470 nm blue light. Our platform was optimized for NIR-mediated optogenetic control by balancing multiple physicochemical properties of the nanomaterial (e.g. size, morphology, structure, emission spectra, concentration), thus providing an early demonstration of rationally-designing nanomaterial-based strategies for advanced neural applications.Nanotechnology-based approaches offer the chemical control required to develop precision tools suitable for applications in neuroscience. We report a novel approach employing hybrid upconversion nanomaterials, combined with the photoresponsive ion channel channelrhodopsin-2 (ChR2), to achieve near-infrared light (NIR)-mediated optogenetic control of neuronal activity. Current optogenetic methodologies rely on using visible light (e.g. 470 nm blue light), which tends to exhibit high scattering and low tissue penetration, to activate ChR2. In contrast, our approach enables the use of 980 nm NIR light, which addresses the short-comings of visible light as an excitation source. This was facilitated by

  12. Lanthanide upconversion luminescence at the nanoscale: fundamentals and optical properties

    NASA Astrophysics Data System (ADS)

    Nadort, Annemarie; Zhao, Jiangbo; Goldys, Ewa M.

    2016-07-01

    Upconversion photoluminescence is a nonlinear effect where multiple lower energy excitation photons produce higher energy emission photons. This fundamentally interesting process has many applications in biomedical imaging, light source and display technology, and solar energy harvesting. In this review we discuss the underlying physical principles and their modelling using rate equations. We discuss how the understanding of photophysical processes enabled a strategic influence over the optical properties of upconversion especially in rationally designed materials. We subsequently present an overview of recent experimental strategies to control and optimize the optical properties of upconversion nanoparticles, focussing on their emission spectral properties and brightness.

  13. Photonic crystal cavity-assisted upconversion infrared photodetector.

    PubMed

    Gan, Xuetao; Yao, Xinwen; Shiue, Ren-Jye; Hatami, Fariba; Englund, Dirk

    2015-05-18

    We describe an upconversion infrared photodetector assisted by a gallium phosphide photonic crystal nanocavity directly coupled to a silicon photodiode. The strongly cavity-enhanced second harmonic signal radiating from the gallium phosphide membrane can thus be efficiently collected by the silicon photodiode, which promises a high photoresponsivity of the upconversion detector as 0.81 A/W with the coupled power of 1W. The integrated upconversion photodetector also functions as a compact autocorrelator with sub-ps resolution for measuring pulse width and chirp.

  14. Upconversion Nanoparticles for Bioimaging and Regenerative Medicine

    PubMed Central

    González-Béjar, María; Francés-Soriano, Laura; Pérez-Prieto, Julia

    2016-01-01

    Nanomaterials are proving useful for regenerative medicine in combination with stem cell therapy. Nanoparticles (NPs) can be administrated and targeted to desired tissues or organs and subsequently be used in non-invasive real-time visualization and tracking of cells by means of different imaging techniques, can act as therapeutic agent nanocarriers, and can also serve as scaffolds to guide the growth of new tissue. NPs can be of different chemical nature, such as gold, iron oxide, cadmium selenide, and carbon, and have the potential to be used in regenerative medicine. However, there are still many issues to be solved, such as toxicity, stability, and resident time. Upconversion NPs have relevant properties such as (i) low toxicity, (ii) capability to absorb light in an optical region where absorption in tissues is minimal and penetration is optimal (note they can also be designed to emit in the near-infrared region), and (iii) they can be used in multiplexing and multimodal imaging. An overview on the potentiality of upconversion materials in regenerative medicine is given. PMID:27379231

  15. View from... UPCON 2016: Bright future for upconversion

    NASA Astrophysics Data System (ADS)

    Jin, Dayong

    2016-09-01

    The synthesis of more efficient upconversion nanomaterials that absorb multiple low-energy photons in the near-infrared and then re-emit in the visible or ultraviolet was a key theme at the first UPCON conference.

  16. Ultrafast fluorescence spectroscopy via upconversion applications to biophysics.

    PubMed

    Xu, Jianhua; Knutson, Jay R

    2008-01-01

    This chapter reviews basic concepts of nonlinear fluorescence upconversion, a technique whose temporal resolution is essentially limited only by the pulse width of the ultrafast laser. Design aspects for upconversion spectrophotofluorometers are discussed, and a recently developed system is described. We discuss applications in biophysics, particularly the measurement of time-resolved fluorescence spectra of proteins (with subpicosecond time resolution). Application of this technique to biophysical problems such as dynamics of tryptophan, peptides, proteins, and nucleic acids is reviewed.

  17. Upconversion luminescence in Yb 3+-doped yttrium aluminum garnets

    NASA Astrophysics Data System (ADS)

    Xu, Xiaodong; Zhao, Zhiwei; Song, Pingxin; Jiang, Benxue; Zhou, Guoqing; Xu, Jun; Deng, Peizhen; Bourdet, Gilbert; Christophe Chanteloup, Jean; Zou, Ji-Ping; Fulop, Annabelle

    2005-03-01

    In this paper, we present results on upconversion luminescence performed on Yb 3+-doped yttrium aluminum garnets under 940 nm excitation. The upconversion luminescence was ascribed to Yb 3+ cooperative luminescence and the presence of rare earth impurity ions. The cooperative luminescence spectra as a function of Yb concentration were measured and the emission intensity variation with Yb concentration was discussed. Yb 3+ energy migration quenched the cooperative luminescence of Yb:YAG crystals with doping level over 15 at%.

  18. Energy pooling upconversion in organic molecular systems.

    PubMed

    LaCount, Michael D; Weingarten, Daniel; Hu, Nan; Shaheen, Sean E; van de Lagemaat, Jao; Rumbles, Garry; Walba, David M; Lusk, Mark T

    2015-04-30

    A combination of molecular quantum electrodynamics, perturbation theory, and ab initio calculations was used to create a computational methodology capable of estimating the rate of three-body singlet upconversion in organic molecular assemblies. The approach was applied to quantify the conditions under which such relaxation rates, known as energy pooling, become meaningful for two test systems, stilbene-fluorescein and hexabenzocoronene-oligothiophene. Both exhibit low intramolecular conversion, but intermolecular configurations exist in which pooling efficiency is at least 90% when placed in competition with more conventional relaxation pathways. For stilbene-fluorescein, the results are consistent with data generated in an earlier experimental investigation. Exercising these model systems facilitated the development of a set of design rules for the optimization of energy pooling. PMID:25793313

  19. An Nd3+-sensitized upconversion nanophosphor modified with a cyanine dye for the ratiometric upconversion luminescence bioimaging of hypochlorite

    NASA Astrophysics Data System (ADS)

    Zou, Xianmei; Liu, Yi; Zhu, Xingjun; Chen, Min; Yao, Liming; Feng, Wei; Li, Fuyou

    2015-02-01

    Excessive or misplaced production of ClO- in living systems is usually associated with many human diseases. Therefore, it is of great importance to develop an effective and sensitive method to detect ClO- in living systems. Herein, we designed an 808 nm excited upconversion luminescence nanosystem, composed of the Nd3+-sensitized core-shell upconversion nanophosphor NaYF4:30%Yb,1%Nd,0.5%Er@NaYF4:20%Nd, which serves as an energy donor, and the ClO--responsive cyanine dye hCy3, which acts as an energy acceptor, for ratiometric upconversion luminescence (UCL) monitoring of ClO-. The detection limit of ClO- for this nanoprobe in aqueous solution is 27 ppb and the nanoprobe was successfully used to detect the ClO- in the living cells by ratiometric upconversion luminescence. Importantly, the nanoprobe realized the detection of ClO- in a mouse model of arthritis, which produced an excess of ROS, under 808 nm irradiation in vivo. The excitation laser efficiently reduced the heating effect, compared to the commonly used 980 nm laser for upconversion systems.Excessive or misplaced production of ClO- in living systems is usually associated with many human diseases. Therefore, it is of great importance to develop an effective and sensitive method to detect ClO- in living systems. Herein, we designed an 808 nm excited upconversion luminescence nanosystem, composed of the Nd3+-sensitized core-shell upconversion nanophosphor NaYF4:30%Yb,1%Nd,0.5%Er@NaYF4:20%Nd, which serves as an energy donor, and the ClO--responsive cyanine dye hCy3, which acts as an energy acceptor, for ratiometric upconversion luminescence (UCL) monitoring of ClO-. The detection limit of ClO- for this nanoprobe in aqueous solution is 27 ppb and the nanoprobe was successfully used to detect the ClO- in the living cells by ratiometric upconversion luminescence. Importantly, the nanoprobe realized the detection of ClO- in a mouse model of arthritis, which produced an excess of ROS, under 808 nm irradiation in

  20. Energy levels and upconversion fluorescence in trivalent thulium-doped yttrium scandium aluminum garnet

    NASA Astrophysics Data System (ADS)

    Gruber, John B.; Seltzer, Michael D.; Hills, Marian E.; Stevens, Sally B.; Morrison, Clyde A.

    1993-02-01

    Absorption spectra of Tm(3+) ions in yttrium scandium aluminum garnet are reported between 1.9 microns and 0.25 micron at 4 K. Laser-excited fluorescence was observed at 4 K from Tm(3+)(4f12) multiplet manifolds 1D2, 1G4, 3F2, and 3H4 to the ground-state manifold 3H6. Emission from 1D2 and 1G4 also includes transitions to Stark levels in manifolds 3F4 and 3H5. Upconversion excited fluorescence was observed between 1D2 and 3F4 at 10 K. Analysis of the fluorescence emission confirms assignments given to individual Stark levels based on an analysis of the absorption spectra. A crystal-field splitting calculation was carried out in which a parameterized Hamiltonian (including Coulombic, spin-orbit, and crystal-field terms in D2 symmetry) was diagonalized for all multiplets of the Tm(3+)(4f12) configuration. The rms deviation between 42 experimental and calculated Stark levels was 8/cm.

  1. Quench-Shield Ratiometric Upconversion Luminescence Nanoplatform for Biosensing.

    PubMed

    Wu, Yong-Xiang; Zhang, Xiao-Bing; Zhang, Dai-Liang; Zhang, Cui-Cui; Li, Jun-Bin; Wu, Yuan; Song, Zhi-Ling; Yu, Ru-Qin; Tan, Weihong

    2016-02-01

    Upconversion nanoparticles (UCNPs) possess several unique features, but they suffer from surface quenching effects caused by the interaction between the UCNPs and fluorophore. Thus, the use of UCNPs for target-induced emission changes for biosensing and bioimaging has been challenging. In this work, fluorophore and UCNPs are effectively separated by a silica transition layer with a thickness of about 4 nm to diminish the surface quenching effect of the UCNPs, allowing a universal and efficient luminescence resonance energy transfer (LRET) ratiometric upconversion luminescence nanoplatform for biosensing applications. A pH-sensitive fluorescein derivative and Hg(2+)-sensitive rhodamine B were chosen as fluoroionphores to construct the LRET nanoprobes. Both showed satisfactory target-triggered ratiometric upconversion luminescence responses in both solution and live cells, indicating that this strategy may find wide applications in the design of nanoprobes for various biorelated targets. PMID:26744211

  2. A paradigm shift in the excitation wavelength of upconversion nanoparticles

    NASA Astrophysics Data System (ADS)

    Jayakumar, Muthu Kumara Gnanasammandhan; Idris, Niagara Muhammad; Huang, Kai; Zhang, Yong

    2014-07-01

    The past two decades witnessed the emergence of upconversion nanoparticles as promising luminophores finding multifarious uses from biological studies to solar cells. Progress in their practical use, however, has been hampered by requirements to be excited within a narrow absorption band at around 980 nm. Since the main constituent of biological tissue - water - absorbs strongly in this region, significant reduction in the penetration depth is anticipated as the 980 nm light gets attenuated travelling through tissues, besides also risking tissue damage from the overheating effect. Just recently, remarkable efforts to engineer the excitation of upconversion nanoparticles to a more suitable wavelength for biological applications were reported. This article gives an insightful view on the different ingenious designs that have been reported and their progression towards the development of upconversion nanoparticles with biologically friendlier excitation wavelength.

  3. Energy upconversion in holmium doped lead-germano-tellurite glass

    SciTech Connect

    Kamma, Indumathi; Reddy, B. Rami

    2010-06-15

    Holmium doped lead-germano-tellurite glass was prepared by the melt quenching technique. The Judd-Ofelt intensity parameters were estimated as {Omega}{sub 2}=7.6x10{sup -20}, {Omega}{sub 4}=12.9x10{sup -20}, and {Omega}{sub 6}=2.5x10{sup -20} cm{sup 2}. Radiative transition probabilities and lifetimes were also determined for some of the levels. Room temperature upconversion emissions have been observed from Ho{sup 3+} at 497 nm under 532 nm laser excitation, and at 557 and 668 nm under 762 nm laser excitation. The upconversion emission mechanisms were found to be due to a step wise excitation process. Upconversion emission intensity enhanced in a heat treated glass.

  4. Confining energy migration in upconversion nanoparticles towards deep ultraviolet lasing

    NASA Astrophysics Data System (ADS)

    Chen, Xian; Jin, Limin; Kong, Wei; Sun, Tianying; Zhang, Wenfei; Liu, Xinhong; Fan, Jun; Yu, Siu Fung; Wang, Feng

    2016-01-01

    Manipulating particle size is a powerful means of creating unprecedented optical properties in metals and semiconductors. Here we report an insulator system composed of NaYbF4:Tm in which size effect can be harnessed to enhance multiphoton upconversion. Our mechanistic investigations suggest that the phenomenon stems from spatial confinement of energy migration in nanosized structures. We show that confining energy migration constitutes a general and versatile strategy to manipulating multiphoton upconversion, demonstrating an efficient five-photon upconversion emission of Tm3+ in a stoichiometric Yb lattice without suffering from concentration quenching. The high emission intensity is unambiguously substantiated by realizing room-temperature lasing emission at around 311 nm after 980-nm pumping, recording an optical gain two orders of magnitude larger than that of a conventional Yb/Tm-based system operating at 650 nm. Our findings thus highlight the viability of realizing diode-pumped lasing in deep ultraviolet regime for various practical applications.

  5. Infrared hyperspectral upconversion imaging using spatial object translation.

    PubMed

    Kehlet, Louis Martinus; Sanders, Nicolai; Tidemand-Lichtenberg, Peter; Dam, Jeppe Seidelin; Pedersen, Christian

    2015-12-28

    In this paper hyperspectral imaging in the mid-infrared wavelength region is realised using nonlinear frequency upconversion. The infrared light is converted to the near-infrared region for detection with a Si-based CCD camera. The object is translated in a predefined grid by motorized actuators and an image is recorded for each position. A sequence of such images is post-processed into a series of monochromatic images in a wavelength range defined by the phasematch condition and numerical aperture of the upconversion system. A standard USAF resolution target and a polystyrene film are used to impart spatial and spectral information unto the source. PMID:26832059

  6. Femtosecond broadband fluorescence upconversion spectroscopy: Improved setup and photometric correction

    SciTech Connect

    Zhang, X.-X.; Wuerth, C.; Resch-Genger, U.; Zhao, L.; Ernsting, N. P.; Sajadi, M.

    2011-06-15

    A setup for fluorescence upconversion spectroscopy (FLUPS) is described which has 80 fs temporal response (fwhm) for emission in the spectral range 425-750 nm. Broadband phase matching is achieved with tilted gate pulses at 1340 nm. Background from harmonics of the gate pulse is removed and sensitivity increased compared to previous designs. Photometric calibration of the upconversion process is performed with a set of fluorescent dyes. For Coumarin 153 in methanol the peak position, bandwidth, and asymmetry depending on delay time are reported.

  7. Visible upconversion lasers in praseodymium-ytterbium-doped fibers

    NASA Astrophysics Data System (ADS)

    Zellmer, H.; Riedel, P.; Tünnermann, A.

    We report on a ZBLAN-fiber-based praseodymium-ytterbium-doped upconversion fiber laser operating in the blue-green with diffraction-limited beam quality. cw output powers of more than 150 mW at 491 nm are achieved for several hours without degradation. The spectroscopic data of the active material and laser parameters including the amplitude noise are discussed.

  8. Development of Pressure sensing Particles through SERS and Upconversion

    NASA Astrophysics Data System (ADS)

    Widejko, Ryan; Wang, Fenglin; Anker, Jeff

    2012-03-01

    With the increasing distance of space travel, there is a critical need for non-invasive point-of-care diagnostic techniques. According to the NASA Human Research Roadmap, the ``lack of non-invasive diagnostic imaging capability and techniques to diagnose identified Exploration Medical Conditions involving internal body parts,'' is a critical capability gap for long distance space travel. To address this gap, we developed a novel technique for non-invasive monitoring of strain on implanted devices. We constructed a prototype tension-indicating washer with an upconversion spectrum that depended upon strain. The washer was made of a polydimethylsiloxane (PDMS) mixture with upconversion particles embedded in it. This mixture was cured onto a lenticular lens. Methylene blue dye solution was sealed between the lenticular lens and PDMS so that pressure on the washer displaced the dye and uncovered the upconversion particles. We also began work on a tension-indicating screw based upon surface enhanced Raman spectroscopy (SERS). Future work for this project is to quantitatively correlate the spectral intensity with pressure, further develop SERS washers, and construct SERS and/or upconversion screws or bolts. Non-invasive tension-indicating devices and techniques such as these can be applied to orthopedics, used as a general technique for measuring micro-strain, verifying proper assembly of equipment, and observing/studying bolt loosening.

  9. Multifunctional Upconversion-Magnetic Hybrid Nanostructured Materials: Synthesis and Bioapplications

    PubMed Central

    Li, Xiaomin; Zhao, Dongyuan; Zhang, Fan

    2013-01-01

    The combination of nanotechnology and biology has developed into an emerging research area: nano-biotechnology. Upconversion nanoparticles (UCNPs) have attracted a great deal of attention in bioapplications due to their high chemical stability, low toxicity, and high signal-to-noise ratio. Magnetic nanoparticles (MNPs) are also well-established nanomaterials that offer controlled size, ability to be manipulated externally, and enhancement of contrast in magnetic resonance imaging (MRI). As a result, these nanoparticles could have many applications in biology and medicine, including protein purification, drug delivery, and medical imaging. Because of the potential benefits of multimodal functionality in biomedical applications, researchers would like to design and fabricate multifunctional upconversion-magnetic hybrid nanostructured materials. The hybrid nanostructures, which combine UCNPs with MNPs, exhibit upconversion fluorescence alongside superparamagnetism property. Such structures could provide a platform for enhanced bioimaging and controlled drug delivery. We expect that the combination of unique structural characteristics and integrated functions of multifunctional upconversion-magnetic nanoparticles will attract increasing research interest and could lead to new opportunities in nano-bioapplications. PMID:23650477

  10. Blue Pr{sup 3+}-doped ZBLAN fiber upconversion laser

    SciTech Connect

    Baney, D.M.; Rankin, G.; Chang, K.

    1996-09-01

    We demonstrate blue laser emission from a direct semiconductor laser-diode-pumped Pr{sup 3+}-doped upconversion fiber laser. This laser produced more than 1 mW of power at a wavelength of 492 nm from pump lasers operating at 830 and 1020 nm. {copyright} {ital 1996 Optical Society of America.}

  11. Upconversion in erbium-doped transparent glass ceramics

    NASA Astrophysics Data System (ADS)

    Jones, Gina Christine

    2005-11-01

    Transparent glass ceramics (TGCs) are a class of materials that are composed of a robust glass matrix which is densely embedded with nanometer-sized fluoride crystals: In bulk, fluoride materials tend to have poor handling and mechanical properties, and can be expensive to produce. In contrast, the forming and handling properties of the TGC are similar to those of the precursor, glass, and are engineered to be robust and mechanically stable. Rare earth ions can be incorporated into the TGC during manufacture and can become partially segregated into the crystalline phase. There they experience the low-phonon energy environment of the fluoride nanocrystallite, which induces long energy level lifetimes and enhanced frequency upconversion. Therefore, rare earth doped TGCs can have the spectroscopic properties of a crystal with the durability of an aluminosilicate glass. Upconversion fluorescence is studied for an aluminosilicate TGC containing LaF3 nanocrystallites and doped with an erbium density of 1.7 x 1020 CM-3. Time gated fluorescence and excitation spectra as well as photoluminescence decays are used to find the nature and origin of this fluorescence. It is determined that energy transfer upconversion occurs only in the nanocrystallite phase and sequential two-photon absorption upconversion occurs in both glass and crystal phases.

  12. Advances in the theoretical understanding of photon upconversion in rare-earth activated nanophosphors.

    PubMed

    Liu, Guokui

    2015-03-21

    Photon upconversion in rare earth activated phosphors involves multiple mechanisms of electronic transitions. Stepwise optical excitation, energy transfer, and various nonlinear and collective light-matter interaction processes act together to convert low-energy photons into short-wavelength light emission. Upconversion luminescence from nanomaterials exhibits additional size and surface dependencies. A fundamental understanding of the overall performance of an upconversion system requires basic theories on the spectroscopic properties of solids containing rare earth ions. This review article surveys the recent progress in the theoretical interpretations of the spectroscopic characteristics and luminescence dynamics of photon upconversion in rare earth activated phosphors. The primary aspects of upconversion processes, including energy level splitting, transition probability, line broadening, non-radiative relaxation and energy transfer, are covered with an emphasis on interpreting experimental observations. Theoretical models and methods for analyzing nano-phenomena in upconversion are introduced with detailed discussions on recently reported experimental results.

  13. Dye-Sensitized Core/Active Shell Upconversion Nanoparticles for Optogenetics and Bioimaging Applications.

    PubMed

    Wu, Xiang; Zhang, Yuanwei; Takle, Kendra; Bilsel, Osman; Li, Zhanjun; Lee, Hyungseok; Zhang, Zijiao; Li, Dongsheng; Fan, Wei; Duan, Chunying; Chan, Emory M; Lois, Carlos; Xiang, Yang; Han, Gang

    2016-01-26

    Near-infrared (NIR) dye-sensitized upconversion nanoparticles (UCNPs) can broaden the absorption range and boost upconversion efficiency of UCNPs. Here, we achieved significantly enhanced upconversion luminescence in dye-sensitized core/active shell UCNPs via the doping of ytterbium ions (Yb(3+)) in the UCNP shell, which bridged the energy transfer from the dye to the UCNP core. As a result, we synergized the two most practical upconversion booster effectors (dye-sensitizing and core/shell enhancement) to amplify upconversion efficiency. We demonstrated two biomedical applications using these UCNPs. By using dye-sensitized core/active shell UCNP embedded poly(methyl methacrylate) polymer implantable systems, we successfully shifted the optogenetic neuron excitation window to a biocompatible and deep tissue penetrable 800 nm wavelength. Furthermore, UCNPs were water-solubilized with Pluronic F127 with high upconversion efficiency and can be imaged in a mouse model.

  14. Dye-Sensitized Core/Active Shell Upconversion Nanoparticles for Optogenetics and Bioimaging Applications.

    PubMed

    Wu, Xiang; Zhang, Yuanwei; Takle, Kendra; Bilsel, Osman; Li, Zhanjun; Lee, Hyungseok; Zhang, Zijiao; Li, Dongsheng; Fan, Wei; Duan, Chunying; Chan, Emory M; Lois, Carlos; Xiang, Yang; Han, Gang

    2016-01-26

    Near-infrared (NIR) dye-sensitized upconversion nanoparticles (UCNPs) can broaden the absorption range and boost upconversion efficiency of UCNPs. Here, we achieved significantly enhanced upconversion luminescence in dye-sensitized core/active shell UCNPs via the doping of ytterbium ions (Yb(3+)) in the UCNP shell, which bridged the energy transfer from the dye to the UCNP core. As a result, we synergized the two most practical upconversion booster effectors (dye-sensitizing and core/shell enhancement) to amplify upconversion efficiency. We demonstrated two biomedical applications using these UCNPs. By using dye-sensitized core/active shell UCNP embedded poly(methyl methacrylate) polymer implantable systems, we successfully shifted the optogenetic neuron excitation window to a biocompatible and deep tissue penetrable 800 nm wavelength. Furthermore, UCNPs were water-solubilized with Pluronic F127 with high upconversion efficiency and can be imaged in a mouse model. PMID:26736013

  15. Upstream Design and 1D-CAE

    NASA Astrophysics Data System (ADS)

    Sawada, Hiroyuki

    Recently, engineering design environment of Japan is changing variously. Manufacturing companies are being challenged to design and bring out products that meet the diverse demands of customers and are competitive against those produced by rising countries(1). In order to keep and strengthen the competitiveness of Japanese companies, it is necessary to create new added values as well as conventional ones. It is well known that design at the early stages has a great influence on the final design solution. Therefore, design support tools for the upstream design is necessary for creating new added values. We have established a research society for 1D-CAE (1 Dimensional Computer Aided Engineering)(2), which is a general term for idea, methodology and tools applicable for the upstream design support, and discuss the concept and definition of 1D-CAE. This paper reports our discussion about 1D-CAE.

  16. DESIGN PACKAGE 1D SYSTEM SAFETY ANALYSIS

    SciTech Connect

    L.R. Eisler

    1995-02-02

    The purpose of this analysis is to systematically identify and evaluate hazards related to the Yucca Mountain Project Exploratory Studies Facility (ESF) Design Package 1D, Surface Facilities, (for a list of design items included in the package 1D system safety analysis see section 3). This process is an integral part of the systems engineering process; whereby safety is considered during planning, design, testing, and construction. A largely qualitative approach was used since a radiological System Safety analysis is not required. The risk assessment in this analysis characterizes the accident scenarios associated with the Design Package 1D structures/systems/components in terms of relative risk and includes recommendations for mitigating all identified risks. The priority for recommending and implementing mitigation control features is: (1) Incorporate measures to reduce risks and hazards into the structure/system/component (S/S/C) design, (2) add safety devices and capabilities to the designs that reduce risk, (3) provide devices that detect and warn personnel of hazardous conditions, and (4) develop procedures and conduct training to increase worker awareness of potential hazards, on methods to reduce exposure to hazards, and on the actions required to avoid accidents or correct hazardous conditions. The scope of this analysis is limited to the Design Package 1D structures/systems/components (S/S/Cs) during normal operations excluding hazards occurring during maintenance and ''off normal'' operations.

  17. Sodium yttrium fluoride based upconversion nano phosphors for biosensing

    NASA Astrophysics Data System (ADS)

    Parameswaran Nampi, Padmaja; Varma, Harikrishna; Biju, P. R.; Kakkar, Tarun; Jose, Gin; Saha, Sikha; Millner, Paul

    2015-06-01

    In the present study, NaYF4-Yb3+/Er3+ having the composition NaYF4-18%Yb3+/2%Er3+ and NaYF4-20%Yb3+/2%Er3+ with and without the addition of PVP (polyvinyl pyrolidone) have been synthesised by a solution method using NaF, yttrium nitrate, ytterbium nitrate and erbium nitrate as precursors. Upconversion spectra of prepared nanomaterial under 980 nm laser excitation have been studied. The variation in upconversion spectra with new born calf serum and myoglobin has been studied. Myoglobin (Mb) may be helpful when used in conjunction with other cardiac markers for rapid determination of acute myocardial ischemia, especially in patients with a typical chest pain or nonspecific ECG changes. The variation of UC fluorescence with addition of Mb indicates the suitability of using NaYF4 based UC nanoparticles in cardiac marker detection. The detailed study is currently under progress.

  18. Functionalized Upconversion Nanoparticles: Versatile Nanoplatforms for Translational Research

    PubMed Central

    Chen, Feng; Bu, Wenbo; Cai, Weibo; Shi, Jianlin

    2013-01-01

    The design, application, and translation of targeted multimodality molecular imaging probes based on nanotechnology has attracted increasing attentions during the last decade and will continue to play vital roles in cancer diagnosis and personalized medicine. With the growing awareness of drawbacks of traditional organic dyes and quantum dots, biocompatible lanthanide ion doped upconversion nanoparticles have emerged as promising candidates for clinically translatable imaging probes, owing to their unique features that are suitable for future targeted multimodal imaging in living subjects. In this review, we summarized the recent advances in the field of functionalized upconversion nanoparticles (f-UCNP) for biological imaging and therapy in vivo, and discussed the future research directions, obstacles ahead, and the potential use of f-UCNP in translational research. PMID:24206131

  19. Upconversion imaging using an all-fiber supercontinuum source.

    PubMed

    Huot, Laurent; Moselund, Peter Morten; Tidemand-Lichtenberg, Peter; Leick, Lasse; Pedersen, Christian

    2016-06-01

    In this Letter, the first demonstration, to the best of our knowledge, of pulsed upconversion imaging using supercontinuum light is presented. A mid-infrared (IR) imaging system was built by combining a mid-IR supercontinuum source emitting between 1.8 and 2.6 μm with upconversion detection. The infrared signal is used to probe a sample and mixed with a synchronized 1550 nm laser pulse inside a lithium niobate (LiNbO3) crystal. The signal is thus upconverted to the 860-970 nm range and acquired on a standard silicon CCD array at a rate of 22 frames per second. In our implementation, spatial features in the sample plane as small as 55 μm could be resolved. PMID:27244390

  20. Mid-infrared nonlinear upconversion imaging and sensing

    NASA Astrophysics Data System (ADS)

    Pedersen, Christian; Tidemand-Lichtenberg, Peter

    2016-03-01

    The mid-IR wavelength range is highly relevant for a number of applications related to gas spectroscopy and spectral analysis of complex molecules such as those including CH bounds. The main obstacles for exploitation of mid-IR applications include suitable and affordable mid-IR light sources for excitation of the sample and sensitive mid-IR detectors. With the advent of mid-IR Quantum cascaded lasers and super continuum light sources new possibilities has emerged. However, low-noise, mid-IR (2-15 μm) detection is still challenging requiring cryogenic cooling to gain sensitivities needed for measurements of fluorescence or absorptions signals. Mid-IR upconversion imaging and detection using nonlinear crystals offers good promise as an alternative, sensitive mid-IR imaging and detection technology. In this paper the fundamental properties of upconversion is discussed.

  1. Subwavelength imaging through ion-beam-induced upconversion

    PubMed Central

    Mi, Zhaohong; Zhang, Yuhai; Vanga, Sudheer Kumar; Chen, Ce-Belle; Tan, Hong Qi; Watt, Frank; Liu, Xiaogang; Bettiol, Andrew A.

    2015-01-01

    The combination of an optical microscope and a luminescent probe plays a pivotal role in biological imaging because it allows for probing subcellular structures. However, the optical resolutions are largely constrained by Abbe's diffraction limit, and the common dye probes often suffer from photobleaching. Here we present a new method for subwavelength imaging by combining lanthanide-doped upconversion nanocrystals with the ionoluminescence imaging technique. We experimentally observed that the ion beam can be used as a new form of excitation source to induce photon upconversion in lanthanide-doped nanocrystals. This approach enables luminescence imaging and simultaneous mapping of cellular structures with a spatial resolution of sub-30 nm. PMID:26560858

  2. Photon upconversion sensitized by a Ru(II)-pyrenyl chromophore

    PubMed Central

    Deng, Fan; Lazorski, Megan S.; Castellano, Felix N.

    2015-01-01

    The near-visible-to-blue singlet fluorescence of anthracene sensitized by a ruthenium chromophore with a long-lived triplet-excited state, [Ru(5-pyrenyl-1,10-phenanthroline)3](PF6)2, in acetonitrile was investigated. Low intensity non-coherent green light was used to selectively excite the sensitizer in the presence of micromolar concentrations of anthracene generating anti-Stokes, singlet fluorescence in the latter, even with incident power densities below 500 μW cm−2. The resultant data are consistent with photon upconversion proceeding from sensitized triplet–triplet annihilation (TTA) of the anthracene acceptor molecules, confirmed through transient absorption spectroscopy as well as static and dynamic photoluminescence experiments. Additionally, quadratic-to-linear incident power regimes for the upconversion process were identified for this composition under monochromatic 488 nm excitation, consistent with a sensitized TTA mechanism ultimately producing the anti-Stokes emission characteristic of anthracene singlet fluorescence. PMID:25987571

  3. Multispectral mid-infrared imaging using frequency upconversion

    NASA Astrophysics Data System (ADS)

    Sanders, Nicolai; Dam, Jeppe Seidelin; Jensen, Ole Bjarlin; Tidemand-Lichtenberg, Peter; Pedersen, Christian

    2013-03-01

    It has recently been shown that it is possible to upconvert infrared images to the near infrared region with high quantum efficiency and low noise by three-wave mixing with a laser field [1]. If the mixing laser is single-frequency, the upconverted image is simply a band-pass filtered version of the infrared object field, with a bandwidth corresponding given by the acceptance parameter of the conversion process, and a center frequency given by the phase-match condition. Tuning of the phase-matched wavelengths has previously been demonstrated by changing the temperature [2] or angle [3 Keywords: Infrared imaging, nonlinear frequency conversion, diode lasers, upconversion ] of the nonlinear material. Unfortunately, temperature tuning is slow, and angle tuning typically results in alignment issues. Here we present a novel approach where the wavelength of the mixing field is used as a tuning parameter, allowing for fast tuning and hence potentially fast image acquisition, paving the way for upconversion based real time multispectral imaging. In the present realization the upconversion module consists of an external cavity tapered diode laser in a Littrow configuration with a computer controlled feedback grating. The output from a tunable laser is used as seed for a fiber amplifier system, boosting the power to approx. 3 W over the tuning range from 1025 to 1085 nm. Using a periodically poled lithium niobate crystal, the infrared wavelength that can be phase-matched is tunable over more than 200 nm. Using a crystal with multiple poling periods allows for upconversion within the entire transparency range of the nonlinear material.

  4. Excitonic luminescence upconversion in a two-dimensional semiconductor

    NASA Astrophysics Data System (ADS)

    Jones, Aaron M.; Yu, Hongyi; Schaibley, John R.; Yan, Jiaqiang; Mandrus, David G.; Taniguchi, Takashi; Watanabe, Kenji; Dery, Hanan; Yao, Wang; Xu, Xiaodong

    2016-04-01

    Photon upconversion is an elementary light-matter interaction process in which an absorbed photon is re-emitted at higher frequency after extracting energy from the medium. This phenomenon lies at the heart of optical refrigeration in solids, where upconversion relies on anti-Stokes processes enabled either by rare-earth impurities or exciton-phonon coupling. Here, we demonstrate a luminescence upconversion process from a negatively charged exciton to a neutral exciton resonance in monolayer WSe2, producing spontaneous anti-Stokes emission with an energy gain of 30 meV. Polarization-resolved measurements find this process to be valley selective, unique to monolayer semiconductors. Since the charged exciton binding energy closely matches the 31 meV A1' optical phonon, we ascribe the spontaneous excitonic anti-Stokes to doubly resonant Raman scattering, where the incident and outgoing photons are in resonance with the charged and neutral excitons, respectively. In addition, we resolve a charged exciton doublet with a 7 meV splitting, probably induced by exchange interactions, and show that anti-Stokes scattering is efficient only when exciting the doublet peak resonant with the phonon, further confirming the excitonic doubly resonant picture.

  5. Confining energy migration in upconversion nanoparticles towards deep ultraviolet lasing

    PubMed Central

    Chen, Xian; Jin, Limin; Kong, Wei; Sun, Tianying; Zhang, Wenfei; Liu, Xinhong; Fan, Jun; Yu, Siu Fung; Wang, Feng

    2016-01-01

    Manipulating particle size is a powerful means of creating unprecedented optical properties in metals and semiconductors. Here we report an insulator system composed of NaYbF4:Tm in which size effect can be harnessed to enhance multiphoton upconversion. Our mechanistic investigations suggest that the phenomenon stems from spatial confinement of energy migration in nanosized structures. We show that confining energy migration constitutes a general and versatile strategy to manipulating multiphoton upconversion, demonstrating an efficient five-photon upconversion emission of Tm3+ in a stoichiometric Yb lattice without suffering from concentration quenching. The high emission intensity is unambiguously substantiated by realizing room-temperature lasing emission at around 311 nm after 980-nm pumping, recording an optical gain two orders of magnitude larger than that of a conventional Yb/Tm-based system operating at 650 nm. Our findings thus highlight the viability of realizing diode-pumped lasing in deep ultraviolet regime for various practical applications. PMID:26739352

  6. High contrast in vivo bioimaging using multiphoton upconversion in novel rare-earth-doped fluoride upconversion nanoparticles

    NASA Astrophysics Data System (ADS)

    Chen, Guanying; Yang, Chunhui; Prasad, Paras N.

    2013-02-01

    Upconversion in rare-earth ions is a sequential multiphoton process that efficiently converts two or more low-energy photons, which are generally near infrared (NIR) light, to produce anti-Stokes emission of a higher energy photon (e.g., NIR, visible, ultraviolet) using continuous-wave (cw) diode laser excitation. Here, we show the engineering of novel, efficient, and biocompatible NIRin-to-NIRout upconversion nanoparticles for biomedical imaging with both excitation and emission being within the "optical transparency window" of tissues. The small animal whole-body imaging with exceptional contrast (signal-to-noise ratio of 310) was shown using BALB/c mice intravenously injected with aqueously dispersed nanoparticles. An imaging depth as deep as 3.2-cm was successfully demonstrated using thick animal tissue (pork) under cw laser excitation at 980 nm.

  7. Near-Infrared Upconversion Chemodosimeter for In Vivo Detection of Cu(2+) in Wilson Disease.

    PubMed

    Liu, Yi; Su, Qianqian; Chen, Min; Dong, Yi; Shi, Yibing; Feng, Wei; Wu, Zhi-Ying; Li, Fuyou

    2016-08-01

    Near-infrared upconversion chemodosimetry is a promising detection method by virtue of the frequency upconversion technique, which shows very high sensitivity and selectivity for the detection of Cu(2+) ions in vitro and in vivo. This method offers a new opportunity for noninvasive diagnosis of Wilson disease associated with Cu(2+) detection in clinical medicine.

  8. Femtosecond Laser-Induced Upconversion Luminescence in Rare-Earth Ions by Nonresonant Multiphoton Absorption.

    PubMed

    Yao, Yunhua; Xu, Cheng; Zheng, Ye; Yang, Chengshuai; Liu, Pei; Jia, Tianqing; Qiu, Jianrong; Sun, Zhenrong; Zhang, Shian

    2016-07-21

    The upconversion luminescence of rare-earth ions has attracted considerable interest because of its important applications in photoelectric conversion, color display, laser device, multiplexed biolabeling, and security printing. Previous studies mainly explored the upconversion luminescence generation through excited state absorption, energy transfer upconversion, and photon avalanche under the continuous wave laser excitation. Here, we focus on the upconversion luminescence generation through a nonresonant multiphoton absorption by using the intense femtosecond pulsed laser excitation and study the upconversion luminescence intensity control by varying the femtosecond laser phase and polarization. We show that the upconversion luminescence of rare-earth ions under the intense femtosecond laser field excitation is easy to be obtained due to the nonresonant multiphoton absorption through the nonlinear interaction between light and matter, which is not available by the continuous wave laser excitation in previous works. We also show that the upconversion luminescence intensity can be effectively controlled by varying the femtosecond pulsed laser phase and polarization, which can open a new technological opportunity to generate and control the upconversion luminescence of rare-earth ions and also can be further extended to the relevant application areas. PMID:27367751

  9. Infrared-to-visible upconversion luminescence in neodymium-doped bismuth-borate glass

    NASA Astrophysics Data System (ADS)

    Oprea, Isabella-Ioana; Hesse, Hartmut; Betzler, Klaus

    2005-10-01

    The upconversion luminescence in Nd3+-doped bismuth-borate glass, excited by 0.8 μm light, was studied in the visible spectral region. Four distinct emission bands were found. From their kinetics, two mechanisms can be shown to be responsible for all four lines: energy-transfer upconversion, slightly dominating, and excited state absorption.

  10. Centrosome Positioning in 1D Cell Migration

    NASA Astrophysics Data System (ADS)

    Adlerz, Katrina; Aranda-Espinoza, Helim

    During cell migration, the positioning of the centrosome and nucleus define a cell's polarity. For a cell migrating on a two-dimensional substrate the centrosome is positioned in front of the nucleus. Under one-dimensional confinement, however, the centrosome is positioned behind the nucleus in 60% of cells. It is known that the centrosome is positioned by CDC42 and dynein for cells moving on a 2D substrate in a wound-healing assay. It is currently unknown, however, if this is also true for cells moving under 1D confinement, where the centrosome position is often reversed. Therefore, centrosome positioning was studied in cells migrating under 1D confinement, which mimics cells migrating through 3D matrices. 3 to 5 μm fibronectin lines were stamped onto a glass substrate and cells with fluorescently labeled nuclei and centrosomes migrated on the lines. Our results show that when a cell changes directions the centrosome position is maintained. That is, when the centrosome is between the nucleus and the cell's trailing edge and the cell changes direction, the centrosome will be translocated across the nucleus to the back of the cell again. A dynein inhibitor did have an influence on centrosome positioning in 1D migration and change of directions.

  11. Modulation of a double-line frequency up-conversion process in cesium vapor

    NASA Astrophysics Data System (ADS)

    Gai, Baodong; Cao, Rui; Xia, Xusheng; Hu, Shu; Liu, Jinbo; Guo, Jingwei; Tan, Yannan; Liu, Wanfa; Jin, Yuqi; Sang, Fengting

    2016-06-01

    We have observed frequency up-conversion in Cs vapor. The pulsed pumping laser beam of 767.2 nm was converted to simultaneous collinear ultraviolet and blue radiation of wavelengths 387.7 and 455.6 nm, respectively (double-line frequency up-conversion). We examined properties of this up-conversion such as energy efficiency and pulse widths. An infrared laser of ~2.4 μm was successful in modulating the laser beam of the frequency up-conversion. The modulation shifts the wavelength of the blue radiation and the intensities of both the blue and ultraviolet radiation. At nanosecond grade, such modulations are expected to have applications in near-infrared up-conversion and optical communications.

  12. Upconversion in Nd{sup 3+}-doped glasses: Microscopic theory and spectroscopic measurements

    SciTech Connect

    Oliveira, S. L.; Sousa, D. F. de; Andrade, A. A.; Nunes, L. A. O.; Catunda, T.

    2008-01-15

    In this work, we report a systematic investigation of upconversion losses and their effects on fluorescence quantum efficiency and fractional thermal loading in Nd{sup 3+}-doped fluoride glasses. The energy transfer upconversion ({gamma}{sub up}) parameter, which describes upconversion losses, was experimentally determined using different methods: thermal lens (TL) technique and steady state luminescence (SSL) measurements. Additionally, the upconversion parameter was also obtained from energy transfer models and excited state absorption measurements. The results reveal that the microscopic treatment provided by the energy transfer models is similar to the macroscopic ones achieved from the TL and SSL measurements because similar {gamma}{sub up} parameters were obtained. Besides, the achieved results also point out the migration-assisted energy transfer according to diffusion-limited regime rather than hopping regime as responsible for the upconversion losses in Nd-doped glasses.

  13. Singlet-based photon upconversion in multichromophore organic thin films (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Weingarten, Daniel H.; LaCount, Michael; Rumbles, Garry; van de Lagemaat, Jao; Lusk, Mark T.; Shaheen, Sean E.

    2015-10-01

    Solid-state energy upconversion has many potential applications, from nonlinear photonics and biophotonics to expanding the spectrum available for solar energy harvest. In organic molecular systems, upconversion is frequently done in solution to mitigate aggregation-induced photoluminescence quenching or to facilitate the diffusion of triplet donors in Triplet-Triplet Annihilation (TTA) systems. Here we demonstrate an organic thin film upconversion system utilizing two-photon absorption (TPA) properties to improve upconversion efficiency. In blend films of Stilbene-420 and Rhodamine 6G we observe a tenfold increase in up-converted fluorescence compared to the fluorescence yield of TPA in pristine stilbene films. While TPA normally has quadratic dependence on excitation intensity, these blend films exhibit sub-quadratic intensity dependence, indicating a combination of linear and quadratic upconversion processes and dramatically improving upconversion efficiency at lower excitation intensities. This improvement in intensity dependence allows for relatively efficient upconversion upon excitation by a nanosecond laser pulse, in contrast to the more expensive femtosecond lasers generally required for excitation in TPA microscopy and similar systems. Time-resolved photoluminescence decay measurements reveal that all excited states involved in this upconversion process are singlets, which indicates the potential for reduced energy losses when compared to TTA upconversion systems and their inherent intersystem-crossing energy losses. We observe emission from both the Rhodamine 6G donor molecules and Stilbene-420 acceptor molecules, indicating the presence of prompt fluorescence from the donor as well as upconversion to the acceptor, and FRET losses from acceptor back to donor. By fitting to a kinetic model we extract rates for these competing processes.

  14. A 1-D dusty plasma photonic crystal

    SciTech Connect

    Mitu, M. L.; Ticoş, C. M.; Toader, D.; Banu, N.; Scurtu, A.

    2013-09-21

    It is demonstrated numerically that a 1-D plasma crystal made of micron size cylindrical dust particles can, in principle, work as a photonic crystal for terahertz waves. The dust rods are parallel to each other and arranged in a linear string forming a periodic structure of dielectric-plasma regions. The dispersion equation is found by solving the waves equation with the boundary conditions at the dust-plasma interface and taking into account the dielectric permittivity of the dust material and plasma. The wavelength of the electromagnetic waves is in the range of a few hundred microns, close to the interparticle separation distance. The band gaps of the 1-D plasma crystal are numerically found for different types of dust materials, separation distances between the dust rods and rod diameters. The distance between levitated dust rods forming a string in rf plasma is shown experimentally to vary over a relatively wide range, from 650 μm to about 1350 μm, depending on the rf power fed into the discharge.

  15. Energy-Cascaded Upconversion in an Organic Dye-Sensitized Core/Shell Fluoride Nanocrystal.

    PubMed

    Chen, Guanying; Damasco, Jossana; Qiu, Hailong; Shao, Wei; Ohulchanskyy, Tymish Y; Valiev, Rashid R; Wu, Xiang; Han, Gang; Wang, Yan; Yang, Chunhui; Ågren, Hans; Prasad, Paras N

    2015-11-11

    Lanthanide-doped upconversion nanoparticles hold promises for bioimaging, solar cells, and volumetric displays. However, their emission brightness and excitation wavelength range are limited by the weak and narrowband absorption of lanthanide ions. Here, we introduce a concept of multistep cascade energy transfer, from broadly infrared-harvesting organic dyes to sensitizer ions in the shell of an epitaxially designed core/shell inorganic nanostructure, with a sequential nonradiative energy transfer to upconverting ion pairs in the core. We show that this concept, when implemented in a core-shell architecture with suppressed surface-related luminescence quenching, yields multiphoton (three-, four-, and five-photon) upconversion quantum efficiency as high as 19% (upconversion energy conversion efficiency of 9.3%, upconversion quantum yield of 4.8%), which is about ~100 times higher than typically reported efficiency of upconversion at 800 nm in lanthanide-based nanostructures, along with a broad spectral range (over 150 nm) of infrared excitation and a large absorption cross-section of 1.47 × 10(-14) cm(2) per single nanoparticle. These features enable unprecedented three-photon upconversion (visible by naked eye as blue light) of an incoherent infrared light excitation with a power density comparable to that of solar irradiation at the Earth surface, having implications for broad applications of these organic-inorganic core/shell nanostructures with energy-cascaded upconversion.

  16. 1D fast coded aperture camera.

    PubMed

    Haw, Magnus; Bellan, Paul

    2015-04-01

    A fast (100 MHz) 1D coded aperture visible light camera has been developed as a prototype for imaging plasma experiments in the EUV/X-ray bands. The system uses printed patterns on transparency sheets as the masked aperture and an 80 channel photodiode array (9 V reverse bias) as the detector. In the low signal limit, the system has demonstrated 40-fold increase in throughput and a signal-to-noise gain of ≈7 over that of a pinhole camera of equivalent parameters. In its present iteration, the camera can only image visible light; however, the only modifications needed to make the system EUV/X-ray sensitive are to acquire appropriate EUV/X-ray photodiodes and to machine a metal masked aperture. PMID:25933861

  17. 1D fast coded aperture camera.

    PubMed

    Haw, Magnus; Bellan, Paul

    2015-04-01

    A fast (100 MHz) 1D coded aperture visible light camera has been developed as a prototype for imaging plasma experiments in the EUV/X-ray bands. The system uses printed patterns on transparency sheets as the masked aperture and an 80 channel photodiode array (9 V reverse bias) as the detector. In the low signal limit, the system has demonstrated 40-fold increase in throughput and a signal-to-noise gain of ≈7 over that of a pinhole camera of equivalent parameters. In its present iteration, the camera can only image visible light; however, the only modifications needed to make the system EUV/X-ray sensitive are to acquire appropriate EUV/X-ray photodiodes and to machine a metal masked aperture.

  18. 1D-VAR Retrieval Using Superchannels

    NASA Technical Reports Server (NTRS)

    Liu, Xu; Zhou, Daniel; Larar, Allen; Smith, William L.; Schluessel, Peter; Mango, Stephen; SaintGermain, Karen

    2008-01-01

    Since modern ultra-spectral remote sensors have thousands of channels, it is difficult to include all of them in a 1D-var retrieval system. We will describe a physical inversion algorithm, which includes all available channels for the atmospheric temperature, moisture, cloud, and surface parameter retrievals. Both the forward model and the inversion algorithm compress the channel radiances into super channels. These super channels are obtained by projecting the radiance spectra onto a set of pre-calculated eigenvectors. The forward model provides both super channel properties and jacobian in EOF space directly. For ultra-spectral sensors such as Infrared Atmospheric Sounding Interferometer (IASI) and the NPOESS Airborne Sounder Testbed Interferometer (NAST), a compression ratio of more than 80 can be achieved, leading to a significant reduction in computations involved in an inversion process. Results will be shown applying the algorithm to real IASI and NAST data.

  19. Reversibly tunable upconversion luminescence by host-guest chemistry.

    PubMed

    Taniguchi, Takaaki; Murakami, Tomoaki; Funatsu, Asami; Hatakeyama, Kazuto; Koinuma, Michio; Matsumoto, Yasumichi

    2014-09-01

    Tuning upconversion (UPC) luminescence using external stimuli and fields, as well as chemical reactions, is expected to lead to novel and efficient optical sensors. Herein, highly tunable UPC luminescence was achieved through a host-guest chemistry approach. Specifically, interlayer ion exchange reactions reversibly tuned the emission intensity and green-red color of Er/Yb-codoped A2La2Ti3O10 layered perovskite, where A corresponds to proton and alkali metal ions, enabling the visualization of host-guest interactions and reactions. PMID:25122035

  20. [C70] fullerene-sensitized triplet-triplet annihilation upconversion.

    PubMed

    Moor, Kyle; Kim, Jae-Hyuk; Snow, Samuel; Kim, Jae-Hong

    2013-11-28

    We herein report the first instance of using pristine C70 as a heavy-atom free organic sensitizer for efficient triplet-triplet annihilation upconversion (UC) for both green-to-blue and red-to-green UC using 9,10-bis(phenylethynyl)anthracene and perylene as acceptors, respectively. C70 achieved quantum yields of 8% and 0.8% for green-to-blue and red-to-green UC, 25 to 35 times higher than C60, and showed improved stability under continuous laser irradiation compared to the benchmark platinum(II)-octaethylporphyrin.

  1. Attenuated total reflectance spectroscopy with chirped-pulse upconversion.

    PubMed

    Shirai, Hideto; Duchesne, Constance; Furutani, Yuji; Fuji, Takao

    2014-12-01

    Chirped-pulse upconversion technique has been applied to attenuated total reflectance (ATR) infrared spectroscopy. An extremely broadband infrared pulse was sent to an ATR diamond prism and the reflected pulse was converted to the visible by using four-wave mixing in krypton gas. Absorption spectra of liquids in the range from 200 to 5500 cm(-1) were measured with a visible spectrometer on a single-shot basis. The system was applied to observe the dynamics of exchanging process of two solvents, water and acetone, which give clear vibrational spectral contrast. We observed that the exchange was finished within ∼ 10 ms. PMID:25606893

  2. Metallophthalocyanines as triplet sensitizers for highly efficient photon upconversion based on sensitized triplet-triplet annihilation.

    PubMed

    Han, J L; You, J; Yonemura, H; Yamada, S; Wang, S R; Li, X G

    2016-08-01

    Soluble palladium and platinum phthalocyanines with coumarin moieties were synthesized with Q bands in the red and near-IR regions, in which the molar extinction coefficients were up to 1.01 × 10(5) cm(-1) mol(-1). These metallophthalocyanines were coupled with rubrene and applied in photon upconversion systems based on triplet-triplet annihilation. The highest upconversion efficiency of the palladium phthalocyanine was 5.6%, which is higher than that of the platinum phthalocyanine-rubrene system. The larger molar extinction coefficient resulted in high upconversion capability (>10(5) cm(-1) mol(-1)) and low saturation incident power (<20 mW cm(-2)). PMID:27431880

  3. Dynamics of the up-conversion emission in holmium doped ZBLAN fiber

    NASA Astrophysics Data System (ADS)

    Wnuk, A.; Kaczkan, M.; Piramidowicz, R.; Mahiou, R.; Bertrand, G.; Joubert, M. F.; Malinowski, M.

    2003-01-01

    The dynamics of up-conversion, green emission under excitation at different infra-red wavelength in Ho3+ doped ZBLAN fiber is reported. Under infrared, 890 nm quasi cw pumping the complicated temporal behavior of the up-conversion signal is strongly influenced by the intermediate I-5(5) state cross relaxation. The mechanisms of the observed up-conversion processes are proposed and the time evolution of the S-5(2) population is described by the rate equation model. Parameters of the model are determined and numerical simulations of the excited state dynamics are performed.

  4. Infrared upconversion for astronomical applications. [laser applications to astronomical spectroscopy of infrared spectra

    NASA Technical Reports Server (NTRS)

    Abbas, M. M.; Kostiuk, T.; Ogilvie, K. W.

    1975-01-01

    The performance of an upconversion system is examined for observation of astronomical sources in the low to middle infrared spectral range. Theoretical values for the performance parameters of an upconversion system for astronomical observations are evaluated in view of the conversion efficiencies, spectral resolution, field of view, minimum detectable source brightness and source flux. Experimental results of blackbody measurements and molecular absorption spectrum measurements using a lithium niobate upconverter with an argon-ion laser as the pump are presented. Estimates of the expected optimum sensitivity of an upconversion device which may be built with the presently available components are given.

  5. Engineering of Lanthanide-Doped Upconversion Nanoparticles for Optical Encoding.

    PubMed

    Huang, Kai; Idris, Niagara Muhammad; Zhang, Yong

    2016-02-17

    Lanthanide-doped upconversion nanoparticles (UCNPs) are an emerging class of luminescent materials that emit UV or visible light under near infra-red (NIR) excitations, thereby possessing a large anti-Stokes shift property. Due to their sharp excitation and emission bands, excellent photo- and chemical stability, low autofluorescence, and high tissue penetration depth of the NIR light used for excitation, UCNPs have surpassed conventional fluorophores in many bioapplications. A better understanding of the mechanism of upconversion, as well as the development of better approaches to preparing UCNPs, have provided more opportunities to explore their use for optical encoding, which has the potential for applications in multiplex detection and imaging. With the current ability to precisely control the microstructure and properties of UCNPs to produce particles of tunable emission, excitation, luminescence lifetime, and size, various strategies for optical encoding based on UCNPs can now be developed. These optical properties of UCNPs (such as emission and excitation wavelengths, ratiometric intensity, luminescence lifetime, and multicolor patterns), and the strategies employed to engineer these properties for optical encoding of UCNPs through homogeneous ion doping, heterogeneous structure fabrication and microbead encapsulation are reviewed. The challenges and potential solutions faced by UCNP optical encoding are also discussed. PMID:26681103

  6. Energy Migration Upconversion in Manganese(II)-Doped Nanoparticles.

    PubMed

    Li, Xiyan; Liu, Xiaowang; Chevrier, Daniel M; Qin, Xian; Xie, Xiaoji; Song, Shuyan; Zhang, Hongjie; Zhang, Peng; Liu, Xiaogang

    2015-11-01

    We report the synthesis and characterization of cubic NaGdF4:Yb/Tm@NaGdF4:Mn core-shell structures. By taking advantage of energy transfer through Yb→Tm→Gd→Mn in these core-shell nanoparticles, we have realized upconversion emission of Mn(2+) at room temperature in lanthanide tetrafluoride based host lattices. The upconverted Mn(2+) emission, enabled by trapping the excitation energy through a Gd(3+) lattice, was validated by the observation of a decreased lifetime from 941 to 532 μs in the emission of Gd(3+) at 310 nm ((6)P(7/2)→(8)S(7/2)). This multiphoton upconversion process can be further enhanced under pulsed laser excitation at high power densities. Both experimental and theoretical studies provide evidence for Mn(2+) doping in the lanthanide-based host lattice arising from the formation of F(-) vacancies around Mn(2+) ions to maintain charge neutrality in the shell layer. PMID:26358961

  7. Frequency Up-Conversion Photon-Type Terahertz Imager.

    PubMed

    Fu, Z L; Gu, L L; Guo, X G; Tan, Z Y; Wan, W J; Zhou, T; Shao, D X; Zhang, R; Cao, J C

    2016-01-01

    Terahertz imaging has many important potential applications. Due to the failure of Si readout integrated circuits (ROICs) and the thermal mismatch between the photo-detector arrays and the ROICs at temperatures below 40 K, there are big technical challenges to construct terahertz photo-type focal plane arrays. In this work, we report pixel-less photo-type terahertz imagers based on the frequency up-conversion technique. The devices are composed of terahertz quantum-well photo-detectors (QWPs) and near-infrared (NIR) light emitting diodes (LEDs) which are grown in sequence on the same substrates using molecular beam epitaxy. In such an integrated QWP-LED device, photocurrent in the QWP drives the LED to emit NIR light. By optimizing the structural parameters of the QWP-LED, the QWP part and the LED part both work well. The maximum values of the internal and external energy up-conversion efficiencies are around 20% and 0.5%. A laser spot of a homemade terahertz quantum cascade laser is imaged by the QWP-LED together with a commercial Si camera. The pixel-less imaging results show that the image blurring induced by the transverse spreading of photocurrent is negligible. The demonstrated pixel-less imaging opens a new way to realize high performance terahertz imaging devices. PMID:27147281

  8. Frequency Up-Conversion Photon-Type Terahertz Imager

    PubMed Central

    Fu, Z. L.; Gu, L. L.; Guo, X. G.; Tan, Z. Y.; Wan, W. J.; Zhou, T.; Shao, D. X.; Zhang, R.; Cao, J. C.

    2016-01-01

    Terahertz imaging has many important potential applications. Due to the failure of Si readout integrated circuits (ROICs) and the thermal mismatch between the photo-detector arrays and the ROICs at temperatures below 40 K, there are big technical challenges to construct terahertz photo-type focal plane arrays. In this work, we report pixel-less photo-type terahertz imagers based on the frequency up-conversion technique. The devices are composed of terahertz quantum-well photo-detectors (QWPs) and near-infrared (NIR) light emitting diodes (LEDs) which are grown in sequence on the same substrates using molecular beam epitaxy. In such an integrated QWP-LED device, photocurrent in the QWP drives the LED to emit NIR light. By optimizing the structural parameters of the QWP-LED, the QWP part and the LED part both work well. The maximum values of the internal and external energy up-conversion efficiencies are around 20% and 0.5%. A laser spot of a homemade terahertz quantum cascade laser is imaged by the QWP-LED together with a commercial Si camera. The pixel-less imaging results show that the image blurring induced by the transverse spreading of photocurrent is negligible. The demonstrated pixel-less imaging opens a new way to realize high performance terahertz imaging devices. PMID:27147281

  9. A double responsive smart upconversion fluorescence sensing material for glycoprotein.

    PubMed

    Guo, Ting; Deng, Qiliang; Fang, Guozhen; Yun, Yaguang; Hu, Yongjin; Wang, Shuo

    2016-11-15

    A novel strategy was developed to prepare double responsive smart upconversion fluorescence material for highly specific enrichment and sensing of glycoprotein. The novel double responsive smart sensing material was synthesized by choosing Horse radish peroxidase (HRP) as modal protein, the grapheme oxide (GO) as support material, upconversion nanoparticles (UCNPs) as fluorescence signal reporter, N-isopropyl acrylamide (NIPAAM) and 4-vinylphenylboronic acid (VPBA) as functional monomers. The structure and component of smart sensing material was investigated by transmission electron microscopy (TEM), Scanning electron microscopy (SEM), X-ray photoelectron spectroscopic (XPS) and Fourier transform infrared (FTIR), respectively. These results illustrated the smart sensing material was prepared successfully. The recognition characterizations of smart sensing material were evaluated, and results showed that the fluorescence intensity of smart sensing material was reduced gradually, as the concentration of protein increased, and the smart sensing material showed selective recognition for HRP among other proteins. Furthermore, the recognition ability of the smart sensing material for glycoprotein was regulated by controlling the pH value and temperature. Therefore, this strategy opens up new way to construct smart material for detection of glycoprotein. PMID:27236725

  10. Vector-based nonlinear upconversion applying center-weighted medians

    NASA Astrophysics Data System (ADS)

    Blume, Holger

    1996-03-01

    One important task in the field of digital video signal processing is the conversion of one standard into another with different field and scan rates. Therefore we have developed a vector based nonlinear upconversion algorithm which applies nonlinear center weighted median filters (CWM). Assuming a 2-channel model of the human visual system with different spatio temporal characteristics, there are contrary demands for the CWM filters. We can meet these demands by a vertical band separation and an application of so-called temporally and spatially dominated CWMs. Hereby errors of the separated channels can be orthogonalized and avoided by an adequate splitting of the spectrum. By this we have achieved a very robust vector error tolerant up-conversion method which significantly improves the interpolation quality. By an appropriate choice of the CWM filter root structures main picture elements are interpolated correctly also if faulty vector fields occur. In order to demonstrate correctness of the deduced interpolation scheme picture content is classified. These classes are distinguished by correct or incorrect vector assignment and correlated or noncorrelated picture content. The mode of operation of the new algorithm is portrayed for each class. Whereas the mode of operation for correlated picture content can be shown by object models this is shown for noncorrelated picture content by the distribution function of the applied CWM filters. The new algorithm has been verified as well by an objective evaluation method the PSNR (peak signal to noise ratio) measurement as by a comprehensive subjective test series.

  11. Frequency Up-Conversion Photon-Type Terahertz Imager

    NASA Astrophysics Data System (ADS)

    Fu, Z. L.; Gu, L. L.; Guo, X. G.; Tan, Z. Y.; Wan, W. J.; Zhou, T.; Shao, D. X.; Zhang, R.; Cao, J. C.

    2016-05-01

    Terahertz imaging has many important potential applications. Due to the failure of Si readout integrated circuits (ROICs) and the thermal mismatch between the photo-detector arrays and the ROICs at temperatures below 40 K, there are big technical challenges to construct terahertz photo-type focal plane arrays. In this work, we report pixel-less photo-type terahertz imagers based on the frequency up-conversion technique. The devices are composed of terahertz quantum-well photo-detectors (QWPs) and near-infrared (NIR) light emitting diodes (LEDs) which are grown in sequence on the same substrates using molecular beam epitaxy. In such an integrated QWP-LED device, photocurrent in the QWP drives the LED to emit NIR light. By optimizing the structural parameters of the QWP-LED, the QWP part and the LED part both work well. The maximum values of the internal and external energy up-conversion efficiencies are around 20% and 0.5%. A laser spot of a homemade terahertz quantum cascade laser is imaged by the QWP-LED together with a commercial Si camera. The pixel-less imaging results show that the image blurring induced by the transverse spreading of photocurrent is negligible. The demonstrated pixel-less imaging opens a new way to realize high performance terahertz imaging devices.

  12. Photon correlation in single-photon frequency upconversion.

    PubMed

    Gu, Xiaorong; Huang, Kun; Pan, Haifeng; Wu, E; Zeng, Heping

    2012-01-30

    We experimentally investigated the intensity cross-correlation between the upconverted photons and the unconverted photons in the single-photon frequency upconversion process with multi-longitudinal mode pump and signal sources. In theoretical analysis, with this multi-longitudinal mode of both signal and pump sources system, the properties of the signal photons could also be maintained as in the single-mode frequency upconversion system. Experimentally, based on the conversion efficiency of 80.5%, the joint probability of simultaneously detecting at upconverted and unconverted photons showed an anti-correlation as a function of conversion efficiency which indicated the upconverted photons were one-to-one from the signal photons. While due to the coherent state of the signal photons, the intensity cross-correlation function g(2)(0) was shown to be equal to unity at any conversion efficiency, agreeing with the theoretical prediction. This study will benefit the high-speed wavelength-tunable quantum state translation or photonic quantum interface together with the mature frequency tuning or longitudinal mode selection techniques.

  13. A double responsive smart upconversion fluorescence sensing material for glycoprotein.

    PubMed

    Guo, Ting; Deng, Qiliang; Fang, Guozhen; Yun, Yaguang; Hu, Yongjin; Wang, Shuo

    2016-11-15

    A novel strategy was developed to prepare double responsive smart upconversion fluorescence material for highly specific enrichment and sensing of glycoprotein. The novel double responsive smart sensing material was synthesized by choosing Horse radish peroxidase (HRP) as modal protein, the grapheme oxide (GO) as support material, upconversion nanoparticles (UCNPs) as fluorescence signal reporter, N-isopropyl acrylamide (NIPAAM) and 4-vinylphenylboronic acid (VPBA) as functional monomers. The structure and component of smart sensing material was investigated by transmission electron microscopy (TEM), Scanning electron microscopy (SEM), X-ray photoelectron spectroscopic (XPS) and Fourier transform infrared (FTIR), respectively. These results illustrated the smart sensing material was prepared successfully. The recognition characterizations of smart sensing material were evaluated, and results showed that the fluorescence intensity of smart sensing material was reduced gradually, as the concentration of protein increased, and the smart sensing material showed selective recognition for HRP among other proteins. Furthermore, the recognition ability of the smart sensing material for glycoprotein was regulated by controlling the pH value and temperature. Therefore, this strategy opens up new way to construct smart material for detection of glycoprotein.

  14. One-step hydrothermal synthesis of carboxyl-functionalized upconversion phosphors for bioapplications.

    PubMed

    Yang, Jianping; Shen, Dengke; Li, Xiaomin; Li, Wei; Fang, Yin; Wei, Yong; Yao, Chi; Tu, Bo; Zhang, Fan; Zhao, Dongyuan

    2012-10-22

    In this paper, we report a facile one-step hydrothermal method to synthesize phase-, size-, and shape-controlled carboxyl-functionalized rare-earth fluorescence upconversion phosphors by using a small-molecule binary acid, such as malonic acid, oxalic acid, succinic acid, or tartaric acid as capping agent. The crystals, from nano- to microstructures with diverse shapes that include nanospheres, microrods, hexagonal prisms, microtubes, microdisks, polygonal columns, and hexagonal tablets, can be obtained with different reaction times, reaction temperatures, molar ratios of capping agent to sodium hydroxide, and by varying the binary acids. Fourier transform infrared, thermogravimetric analysis, and upconversion luminescence spectra measurements indicate that the synthesized NaYF(4):Yb/Er products with hydrophilic carboxyl-functionalized surface offer efficient upconversion luminescent performance. Furthermore, the antibody/secondary antibody conjugation can be realized by the carboxyl-functionalized surfaces of the upconversion phosphors, thus indicating the potential bioapplications of these kinds of materials.

  15. Metal-Organic Frameworks Modulated by Doping Er(3+) for Up-Conversion Luminescence.

    PubMed

    Zhang, Xindan; Li, Bin; Ma, Heping; Zhang, Liming; Zhao, Haifeng

    2016-07-13

    Here we present metal-organic frameworks prepared by a one-step synthesis method, possessing both architectural properties of MOF building and up-conversion luminescence of rare earth Er(3+) (hereafter denoted as Up-MOFs). Up-MOFs have characteristic up-conversion emissions at 520, 540, and 651 nm under the excitation of 980 nm owing to the multiple photon absorption. The up-conversion mechanism of these Up-MOFs has been discussed, and it can be attributed to the excited state absorption process. The design and synthesis of Up-MOF materials possessing near-infrared region excitation and up-conversion luminescence are fully expected to be candidates for the advancement of applications in bioimaging, sensors, optoelectronics, and energy conversion/storage devices.

  16. Color Tunable and Upconversion Luminescence in Yb-Tm Co-Doped Yttrium Phosphate Inverse Opal Photonic Crystals.

    PubMed

    Wang, Siqin; Qiu, Jianbei; Wang, Qi; Zhou, Dacheng; Yang, Zhengwen

    2016-04-01

    For this paper, YPO4: Tm, Yb inverse opals with the photonic band gaps at 475 nm and 655 nm were prepared by polystyrene colloidal crystal templates. We investigated the influence of photonic band gaps on the Tm-Yb upconversion emission which was in the YPO4: Tm Yb inverse opal photonic crystals. Comparing with the reference sample, significant suppression of both the blue and red upconversion luminescence of Tm3+ ions were observed in the inverse opals. The color purity of the blue emission was improved in the inverse opal by the suppression of red upconversion emission. Additionally, mechanism of upconversion emission in the inverse opal was discussed. We believe that the present work will be valuable for not only the foundational study of upconversion emission modification but also the development of new optical devices in upconversion lighting and display. PMID:27451700

  17. Color Tunable and Upconversion Luminescence in Yb-Tm Co-Doped Yttrium Phosphate Inverse Opal Photonic Crystals.

    PubMed

    Wang, Siqin; Qiu, Jianbei; Wang, Qi; Zhou, Dacheng; Yang, Zhengwen

    2016-04-01

    For this paper, YPO4: Tm, Yb inverse opals with the photonic band gaps at 475 nm and 655 nm were prepared by polystyrene colloidal crystal templates. We investigated the influence of photonic band gaps on the Tm-Yb upconversion emission which was in the YPO4: Tm Yb inverse opal photonic crystals. Comparing with the reference sample, significant suppression of both the blue and red upconversion luminescence of Tm3+ ions were observed in the inverse opals. The color purity of the blue emission was improved in the inverse opal by the suppression of red upconversion emission. Additionally, mechanism of upconversion emission in the inverse opal was discussed. We believe that the present work will be valuable for not only the foundational study of upconversion emission modification but also the development of new optical devices in upconversion lighting and display.

  18. The Quality of In Vivo Upconversion Fluorescence Signals Inside Different Anatomic Structures.

    PubMed

    Wang, Lijiang; Draz, Mohamed Shehata; Wang, Wei; Liao, Guodong; Xu, Yuhong

    2015-02-01

    Fluorescence imaging is a broadly interesting and rapidly growing strategy for non-invasive clinical applications. However, because of interference from light scattering, absorbance, and tissue autofluorescence, the images can exhibit low sensitivity and poor quality. Upconversion fluorescence imaging, which is based on the use of near-infrared (NIR) light for excitation, has recently been introduced as an improved approach to minimize the effects of light scattering and tissue autofluorescence. This strategy is promising for ultrasensitive and deep tissue imaging applications. However, the emitted upconversion fluorescence signals are primarily in the visible range and are likely to be absorbed and scattered by tissues. Therefore, different anatomic structures could impose various effects on the quality of the images. In this study, we used upconversion-core/silica-shell nanoprobes to evaluate the quality of upconversion fluorescence at different anatomic locations in athymic nude mice. The nanoprobe contained an upconversion core, which was green (β-NaYF4:Yb3+/Ho3+) or red (β-NaYF4:Yb3+/Er3+), and a nonporous silica shell to allow for multicolor imaging. High-quality upconversion fluorescence signals were detected with signal-to-noise ratios of up to 170 at tissue depths of up to - 1.0 cm when a 980 nm laser excitation source and a bandpass emission filter were used. The presence of dense tissue structures along the imaging path reduced the signal intensity and imaging quality, and nanoprobes with longer-wavelength emission spectra were therefore preferable. This study offers a detailed analysis of the quality of upconversion signals in vivo inside different anatomic structures. Such information could be essential for the analysis of upconversion fluorescence images in any in vivo biodiagnostic and microbial tracking applications.

  19. A Pr 3+-doped ZBLAN fibre upconversion laser pumped by an Yb 3+-doped silica fibre laser

    NASA Astrophysics Data System (ADS)

    Pask, H. M.; Tropper, A. C.; Hanna, D. C.

    1997-02-01

    An Yb 3+-doped silica fibre laser pumped at 840 nm has been used to provide the two pump wavelengths, 840 nm and 1020 nm, required for pumping a Pr 3+-doped ZBLAN fibre upconversion laser. The performance of the upconversion laser at 491, 520 and 635 nm is presented, with measurements of fibre loss at 635 nm and 520 nm which indicate that fibre losses are an important factor limiting the performance of the upconversion laser.

  20. 1D-1D Coulomb drag in a 6 Million Mobility Bi-layer Heterostructure

    NASA Astrophysics Data System (ADS)

    Bilodeau, Simon; Laroche, Dominique; Xia, Jian-Sheng; Lilly, Mike; Reno, John; Pfeiffer, Loren; West, Ken; Gervais, Guillaume

    We report Coulomb drag measurements in vertically-coupled quantum wires. The wires are fabricated in GaAs/AlGaAs bilayer heterostructures grown from two different MBE chambers: one at Sandia National Laboratories (1.2M mobility), and the other at Princeton University (6M mobility). The previously observed positive and negative drag signals are seen in both types of devices, demonstrating the robustness of the result. However, attempts to determine the temperature dependence of the drag signal in the 1D regime proved challenging in the higher mobility heterostructure (Princeton), in part because of difficulties in aligning the wires within the same transverse subband configuration. Nevertheless, this work, performed at the Microkelvin laboratory of the University of Florida, is an important proof-of-concept for future investigations of the temperature dependence of the 1D-1D drag signal down to a few mK. Such an experiment could confirm the Luttinger charge density wave interlocking predicted to occur in the wires. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL8500.

  1. One-Step Hydrothermal Synthesis of Butanetetracarboxylic Acid-Coated NaYF₄:Yb³⁺, Er³⁺ Upconversion Phosphors with Enhancement Upconversion Luminescence.

    PubMed

    Zhang, Liming; Mao, Lanlan; Lu, Zhuoxuan; Deng, Yan; He, Nongyue

    2016-01-01

    Butanetetracarboxylic acid (BTCA)/NaYF₄:Yb³⁺, Er³⁺ upconversion phosphors have been successfully synthesized by a one-step hydrothermal method. The SEM and XRD results show the as-prepared phosphors exhibit main hexagonal lattice structures and uniform morphologies. FT-IR spectra confirm that the surface of as-prepared phosphors is inherently modified with the carboxyl groups. Under the excitation of 980 nm, it has been observed that BTCA/NaYF₄:Yb³⁺, Er³⁺ upconversion phosphors have a higher upconversion luminescence efficiency than that coated with citrate, ethylenediamine tetraacetic acid (EDTA), or polyacrylic acid (PAA). These results indicate that the BTCA/NaYF₄:Yb³⁺, Er³⁺ phosphors may have superior optical properties, and thus have great potential for biological applications. PMID:27398591

  2. [Initial research of one-beam pumping up-conversion 3D volumetric display based on Er:ZBLAN glass].

    PubMed

    Chen, Xiao-bo; Li, Mei-xian; Wen, Ou; Zhang, Fu-chu; Song, Zeng-fu

    2003-06-01

    This paper investigates one-beam pumping up-conversion three-dimensional volumetric display, which is based on a Er:ZBLAN fluoride glass. The light-length of the facula of one-beam up-conversion luminescence was studied by a 966 nm semiconductor laser. The up-conversion luminescence spectrum was also obtained. It was found that the property of one-beam pumping three-dimensional volumetric display can be improved significantly by 1.52 microns LD laser multi-photon up-conversion, this finding has not been reported.

  3. Highly improved upconversion luminescence in NaGd(WO4)2:Yb3+/Tm3+ inverse opal photonic crystals

    NASA Astrophysics Data System (ADS)

    Wang, Yunfeng; Xu, Wen; Cui, Shaobo; Xu, Sai; Yin, Ze; Song, Hongwei; Zhou, Pingwei; Liu, Xiaoyan; Xu, Lin; Cui, Haining

    2015-01-01

    The upconversion luminescence (UCL) of rare earth (RE) ions doped nanomaterials has attracted extensive interest because of its wide and great potential applications. However, the lower UCL efficiency is still an obstacle for real applications. Photonic modulation is a novel way to improve the efficiency of UCL. In this work, NaGd(WO4)2:Yb3+/Tm3+ inverse opal photonic crystals (IOPCs) were fabricated through the polymethylmethacrylate (PMMA) template and the modification of the IOPC structure on the emission spectra and dynamics of Tm3+ ions was systemically studied. It is interesting to observe that in the IOPCs, the high-order UCL 1D2-3H6/3F4 was relatively enhanced. At the same time, the local thermal effect induced by laser irradiation was suppressed. Furthermore, the overall intensity ratio of visible UCL to near-infrared (NIR) down-conversion luminescence (DCL) was 2.8-8 times improved than that of the grinded reference (REF) and independent of the photonic stop band (PSB). The studies on UCL dynamics indicated that the nonradiative transition rate of Tm3+ was considerably suppressed. The facts above indicated that in the IOPCs the UCL efficiency of Tm3+ was largely improved due to the periodic macroporous structure.The upconversion luminescence (UCL) of rare earth (RE) ions doped nanomaterials has attracted extensive interest because of its wide and great potential applications. However, the lower UCL efficiency is still an obstacle for real applications. Photonic modulation is a novel way to improve the efficiency of UCL. In this work, NaGd(WO4)2:Yb3+/Tm3+ inverse opal photonic crystals (IOPCs) were fabricated through the polymethylmethacrylate (PMMA) template and the modification of the IOPC structure on the emission spectra and dynamics of Tm3+ ions was systemically studied. It is interesting to observe that in the IOPCs, the high-order UCL 1D2-3H6/3F4 was relatively enhanced. At the same time, the local thermal effect induced by laser irradiation was

  4. Engineered Upconversion Nanoparticles for Resolving Protein Interactions inside Living Cells.

    PubMed

    Drees, Christoph; Raj, Athira Naduviledathu; Kurre, Rainer; Busch, Karin B; Haase, Markus; Piehler, Jacob

    2016-09-12

    Upconversion nanoparticles (UCNPs) convert near-infrared into visible light at much lower excitation densities than those used in classic two-photon absorption microscopy. Here, we engineered <50 nm UCNPs for application as efficient lanthanide resonance energy transfer (LRET) donors inside living cells. By optimizing the dopant concentrations and the core-shell structure for higher excitation densities, we observed enhanced UCNP emission as well as strongly increased sensitized acceptor fluorescence. For the application of these UCNPs in complex biological environments, we developed a biocompatible surface coating functionalized with a nanobody recognizing green fluorescent protein (GFP). Thus, rapid and specific targeting to GFP-tagged fusion proteins in the mitochondrial outer membrane and detection of protein interactions by LRET in living cells was achieved. PMID:27510808

  5. Engineered Upconversion Nanoparticles for Resolving Protein Interactions inside Living Cells.

    PubMed

    Drees, Christoph; Raj, Athira Naduviledathu; Kurre, Rainer; Busch, Karin B; Haase, Markus; Piehler, Jacob

    2016-09-12

    Upconversion nanoparticles (UCNPs) convert near-infrared into visible light at much lower excitation densities than those used in classic two-photon absorption microscopy. Here, we engineered <50 nm UCNPs for application as efficient lanthanide resonance energy transfer (LRET) donors inside living cells. By optimizing the dopant concentrations and the core-shell structure for higher excitation densities, we observed enhanced UCNP emission as well as strongly increased sensitized acceptor fluorescence. For the application of these UCNPs in complex biological environments, we developed a biocompatible surface coating functionalized with a nanobody recognizing green fluorescent protein (GFP). Thus, rapid and specific targeting to GFP-tagged fusion proteins in the mitochondrial outer membrane and detection of protein interactions by LRET in living cells was achieved.

  6. Photon avalanche up-conversion in holmium doped fluoride glasses

    SciTech Connect

    Chen, Y.H.; Liu, G.K.; Beitz, J.V.; Jie Wang

    1996-08-01

    Photon avalanche green up-conversion emission centered at 545 nm has been observed in Ho{sup 3+} doped and Ho{sup 3+}, Tm{sup 3+} co-doped ZrF{sub 4}-based fluoride glasses when excited near 585 nm which is off resonance with any ground state absorption bands of either Ho{sup 3+} or Tm{sup 3+} ions. Detailed spectral measurements and analysis suggest that the 545 nm emission occurs from the {sup 5}S{sub 2},{sup 5}F{sub 4} states of Ho{sup 3+} that are populated by excited state absorption from the {sup 5}I{sub 7} state of Ho{sup 3+}. Strong cross-relaxation that efficiently populates the {sup 5}I{sub 7} state makes the photon avalanche process possible in this system.

  7. Multimodal cancer imaging using lanthanide-based upconversion nanoparticles.

    PubMed

    Yang, Dongmei; Li, Chunxia; Lin, Jun

    2015-01-01

    Multimodal nanoprobes that integrate different imaging modalities in one nano-system could offer synergistic effect over any modality alone to satisfy the higher requirements on the efficiency and accuracy for clinical diagnosis and medical research. Upconversion nanoparticles (UCNPs), particularly lanthanide (Ln)-based NPs have been regarded as an ideal building block for constructing multimodal bioprobes due to their fascinating properties. In this review, we first summarize recent advances in the optimizations of existing UCNPs. In particular, we highlight the applications of Ln-based UCNPs for multimodal cancer imaging in vitro and in vivo. The explorations of UCNPs-based multimodal nanoprobes for targeting diagnosis and imaging-guided therapeutics are also presented. Finally, the challenges and perspectives of Ln-based UCNPs in this rapid growing field are discussed. PMID:26293416

  8. Quantum frequency up-conversion of continuous variable entangled states

    SciTech Connect

    Liu, Wenyuan; Wang, Ning; Li, Zongyang; Li, Yongmin

    2015-12-07

    We demonstrate experimentally quantum frequency up-conversion of a continuous variable entangled optical field via sum-frequency-generation process. The two-color entangled state initially entangled at 806 and 1518 nm with an amplitude quadrature difference squeezing of 3.2 dB and phase quadrature sum squeezing of 3.1 dB is converted to a new entangled state at 530 and 1518 nm with the amplitude quadrature difference squeezing of 1.7 dB and phase quadrature sum squeezing of 1.8 dB. Our implementation enables the observation of entanglement between two light fields spanning approximately 1.5 octaves in optical frequency. The presented scheme is robust to the excess amplitude and phase noises of the pump field, making it a practical building block for quantum information processing and communication networks.

  9. Synchronous detection in monolithically integrated AM upconversion receivers

    NASA Astrophysics Data System (ADS)

    Vanderplas, Jacob

    1990-01-01

    The design of a synchronous detector for an integrated AM (Amplitude Modulated) upconversion receiver with a tuning range from 150 kHz to 30 MHz is addressed. The following are described: synchronous detector architecture; design of the synchronous detector HF circuits; design of the on-chip continuous time audio low pass filter; and design of the synchronous detector LF circuits. The results of the calculations combined with the results of the prototypes confirm the technical feasibility of a synchronous detector that guarantees at least 50 dB additional channel selectivity. However, the relatively large amount of overhead circuitry for the regeneration of the carrier makes the economic feasibility for the consumer market doubtful.

  10. Dispersing upconversion nanocrystals in a single silicon microtube

    PubMed Central

    Li, Hanyang; Wang, Yan; Li, Hui; Zhang, Yundong; Yang, Jun

    2016-01-01

    Nanocrystals of Ln3+ (Ln = Yb, Tm and Ho) doped β-NaLuF4 with average diameter about 200 nm are dispersed in silica-based microtube (MT) by a simple flame heating method. The fabricated microtube has a diameter range from 2 μm to 30 μm and lengths up to hundreds microns. The fluorescence of upconversion nanocrystals (UCNCs) can propagate along a single MT and couple into another MT through evanescent field. The guiding performance of the single UCNCs doped MT is measured to prove that it can be used as an active waveguide. Moreover, optical temperature sensing based on the single UCNCs-MT is also demonstrated, and the sensitivity of UCNCs-MT is significantly enough for thermometry applications in the range of 298–383 K. PMID:27779210

  11. Texaphyrin sensitized near-IR-to-visible photon upconversion.

    PubMed

    Deng, Fan; Sun, Wenfang; Castellano, Felix N

    2014-05-01

    Near-IR (NIR) absorption from a Cd(ii) texaphyrin (TXP) has been successfully coupled with rubrene triplet acceptors/annihilators in vacuum degassed dichloromethane to upconvert NIR (670-800 nm) incident photons into yellow fluorescence through sensitized triplet-triplet annihilation. Stern-Volmer analysis of dynamic energy transfer quenching of TXP by rubrene using transient absorption spectroscopy revealed Stern-Volmer and bimolecular quenching constants of 21,000 M(-1) and 5.7 × 10(8) M(-1) s(-1) respectively, for the triplet-triplet energy transfer process. The upconverted emission intensity with respect to the incident excitation power density at 750 nm was shown to vary between quadratic and linear, illustrating the expected kinetic limits for the light producing photochemistry under continuous wave illumination. Furthermore, with increasing TXP sensitizer concentration, the characteristic quadratic-to-linear crossover point shifted to lower incident photon power density. This is consistent with the notion that stronger photon capture in the sensitizer leads to experimental conditions promoting upconversion under milder excitation conditions. The maximum quantum yield of the TXP-sensitized rubrene upconverted fluorescence was 1.54 ± 0.04% under dilute conditions determined relative to [Os(phen)3](PF6)2 under continuous wave excitation conditions. This saturating quantum efficiency was realized when the incident light power dependence reached the quadratic-to-linear crossover point and was constant over the region where the composition displayed linear response to incident light power density. In pulsed laser experiments at higher sensitizer concentrations, the triplet-triplet annihilation quantum yield was determined to saturate at approximately 13%, corresponding to an upconversion yield of ∼10%, suggesting that the dichloromethane solvent either lowers the T2 state of the rubrene acceptor or is somehow attenuating the annihilation reaction between

  12. Upconversion nanoparticles with a strong acid-resistant capping

    NASA Astrophysics Data System (ADS)

    Recalde, Ileana; Estebanez, Nestor; Francés-Soriano, Laura; Liras, Marta; González-Béjar, María; Pérez-Prieto, Julia

    2016-03-01

    Water-dispersible upconversion nanoparticles (β-NaYF4:Yb3+,Er3+, UCNP) coated with a thin shell of a biocompatible copolymer comprising 2-hydroxyethylmethacrylate (HEMA) and 2-acrylamido-2-methyl-1-propanesulphonsulphonic acid (AMPS), which we will term COP, have been prepared by multidentate grafting. This capping is remarkably resistant to strong acidic conditions as low as pH 2. The additional functionality of the smart UCNP@COP nanosystem has been proved by its association to a well-known photosensitizer (namely, methylene blue, MB). The green-to-red emission ratio of the UC@COP@MB nanohybrid exhibits excellent linear dependence in the 7 to 2 pH range as a consequence of the release of the dye as the pH decreases.Water-dispersible upconversion nanoparticles (β-NaYF4:Yb3+,Er3+, UCNP) coated with a thin shell of a biocompatible copolymer comprising 2-hydroxyethylmethacrylate (HEMA) and 2-acrylamido-2-methyl-1-propanesulphonsulphonic acid (AMPS), which we will term COP, have been prepared by multidentate grafting. This capping is remarkably resistant to strong acidic conditions as low as pH 2. The additional functionality of the smart UCNP@COP nanosystem has been proved by its association to a well-known photosensitizer (namely, methylene blue, MB). The green-to-red emission ratio of the UC@COP@MB nanohybrid exhibits excellent linear dependence in the 7 to 2 pH range as a consequence of the release of the dye as the pH decreases. Electronic supplementary information (ESI) available: Additional spectra and data of HEMA, AMPS, COP, UCNP@oleate, UCNP@COP, and UCNP@COP@MB. See DOI: 10.1039/c5nr06653k

  13. Texaphyrin sensitized near-IR-to-visible photon upconversion.

    PubMed

    Deng, Fan; Sun, Wenfang; Castellano, Felix N

    2014-05-01

    Near-IR (NIR) absorption from a Cd(ii) texaphyrin (TXP) has been successfully coupled with rubrene triplet acceptors/annihilators in vacuum degassed dichloromethane to upconvert NIR (670-800 nm) incident photons into yellow fluorescence through sensitized triplet-triplet annihilation. Stern-Volmer analysis of dynamic energy transfer quenching of TXP by rubrene using transient absorption spectroscopy revealed Stern-Volmer and bimolecular quenching constants of 21,000 M(-1) and 5.7 × 10(8) M(-1) s(-1) respectively, for the triplet-triplet energy transfer process. The upconverted emission intensity with respect to the incident excitation power density at 750 nm was shown to vary between quadratic and linear, illustrating the expected kinetic limits for the light producing photochemistry under continuous wave illumination. Furthermore, with increasing TXP sensitizer concentration, the characteristic quadratic-to-linear crossover point shifted to lower incident photon power density. This is consistent with the notion that stronger photon capture in the sensitizer leads to experimental conditions promoting upconversion under milder excitation conditions. The maximum quantum yield of the TXP-sensitized rubrene upconverted fluorescence was 1.54 ± 0.04% under dilute conditions determined relative to [Os(phen)3](PF6)2 under continuous wave excitation conditions. This saturating quantum efficiency was realized when the incident light power dependence reached the quadratic-to-linear crossover point and was constant over the region where the composition displayed linear response to incident light power density. In pulsed laser experiments at higher sensitizer concentrations, the triplet-triplet annihilation quantum yield was determined to saturate at approximately 13%, corresponding to an upconversion yield of ∼10%, suggesting that the dichloromethane solvent either lowers the T2 state of the rubrene acceptor or is somehow attenuating the annihilation reaction between

  14. 3D Rare earth porous coordination frameworks with formamide generated in situ syntheses: Crystal structure and down- and up-conversion luminescence

    SciTech Connect

    Ma, Xue; Tian, Jing; Yang, Hong-Y.; Zhao, Kai; Li, Xia

    2013-05-01

    The reaction of RE(NO)₃·6H₂O and formamide yielded the coordination polymers, [RE(HCOO)₄]⁻[NH₂CHNH₂]⁺ (RE=Y 1, Eu 2, Gd 3, Tb 4, Dy 5, Er 6, and Yb 7). They possess 3D porous frameworks with the 1D rhombic channels occupied by [NH₂CHNH₂]⁺ cations. Complexes 2 and 4 display the characteristic down-conversion emissions corresponding to ⁵D₀→⁷FJ (J=1–4) transitions of Eu(III) ion and ⁵D₄→⁷FJ (J=6–3) transitions of Tb(III) ion, respectively. Longer lifetime values of 2.128±0.002 ms (⁵D₀) for 2 and 2.132±0.002 ms (⁵D₄) for 4 have been observed. The up-conversion spectra of the Y:Yb,Er and Gd:Yb,Er codoped complexes exhibit three emission bands around 410 (⁴H9/2→⁴I15/2, blue), 518–570 (⁴S3/2, ²H11/2→⁴I15/2, green), and 655 nm (⁴F9/2→⁴I15/2, red). - Graphical Abstract: The complexes [RE(HCOO)₄]⁻[NH₂CHNH₂]⁺ possess 3D porous frameworks. Eu(III) and Tb(III) complexes show characteristic emission of Ln(III) ions. The up-conversion emission of the Y:Yb,Er and Gd:Yb,Er codoped complexes was observed. Highlights: •The reaction of RE(NO)₃·6H₂O and formamide produced complexes [RE(HCOO)₄]⁻[NH₂CHNH₂]⁺. • The complexes possess 3D frameworks with the 1D channels occupied by [NH₂CHNH₂]+ cations. • Eu(III)/Tb(III) complexes display the characteristic down-conversion emission of Ln(III) ions. • The Y:Yb,Er and Gd:Yb,Er doped complexes exhibit the up-conversion emission.

  15. Human serotonin 1D receptor is encoded by a subfamily of two distinct genes: 5-HT1D alpha and 5-HT1D beta.

    PubMed Central

    Weinshank, R L; Zgombick, J M; Macchi, M J; Branchek, T A; Hartig, P R

    1992-01-01

    The serotonin 1D (5-HT1D) receptor is a pharmacologically defined binding site and functional receptor site. Observed variations in the properties of 5-HT1D receptors in different tissues have led to the speculation that multiple receptor proteins with slightly different properties may exist. We report here the cloning, deduced amino acid sequences, pharmacological properties, and second-messenger coupling of a pair of human 5-HT1D receptor genes, which we have designated 5-HT1D alpha and 5-HT1D beta due to their strong similarities in sequence, pharmacological properties, and second-messenger coupling. Both genes are free of introns in their coding regions, are expressed in the human cerebral cortex, and can couple to inhibition of adenylate cyclase activity. The pharmacological binding properties of these two human receptors are very similar, and match closely the pharmacological properties of human, bovine, and guinea pig 5-HT1D sites. Both receptors exhibit high-affinity binding of sumatriptan, a new anti-migraine medication, and thus are candidates for the pharmacological site of action of this drug. Images PMID:1565658

  16. Er{sup 3+}/Yb{sup 3+}co-doped bismuth molybdate nanosheets upconversion photocatalyst with enhanced photocatalytic activity

    SciTech Connect

    Adhikari, Rajesh; Gyawali, Gobinda; Cho, Sung Hun; Narro-García, R.; Sekino, Tohru; Lee, Soo Wohn

    2014-01-15

    In this paper, we report the microwave hydrothermal synthesis of Er{sup 3+}/Yb{sup 3+} co-doped Bi{sub 2}MoO{sub 6} upconversion photocatalyst. Crystal structure, morphology, elemental composition, optical properties and BET surface area were analyzed in detail. Infrared to visible upconversion luminescence at 532 nm and 546 nm of the co-doped samples was investigated under excitation at 980 nm. The results revealed that the co-doping of Er{sup 3+}/Yb{sup 3+} into Bi{sub 2}MoO{sub 6} exhibited enhanced photocatalytic activity for the decomposition of rhodamine B under simulated solar light irradiation. Enhanced photocatalytic activity can be attributed to the energy transfer between Er{sup 3+}/Yb{sup 3+} and Bi{sub 2}MoO{sub 6} via infrared to visible upconversion from Er{sup 3+}/Yb{sup 3+} ion and higher surface area of the Bi{sub 2}MoO{sub 6} nanosheets. Therefore, this synthetic approach may exhibit a better alternative to fabricate upconversion photocatalyst for integral solar light absorption. - Graphical abstract: Schematic illustration of the upconversion photocatalysis. Display Omitted - Highlights: • Er{sup 3+}/Yb{sup 3+} co-doped Bi{sub 2}MoO{sub 6} upconversion photocatalyst is successfully synthesized. • We obtained the nanosheets having high surface area. • Upconversion of IR to visible light was confirmed. • Upconversion phenomena can be utilized for effective photocatalysis.

  17. Experimental demonstration of plasmon enhanced energy transfer rate in NaYF4:Yb3+,Er3+ upconversion nanoparticles

    PubMed Central

    Lu, Dawei; Mao, Chenchen; Cho, Suehyun K.; Ahn, Sungmo; Park, Wounjhang

    2016-01-01

    Energy transfer upconversion (ETU) is known to be the most efficient frequency upconversion mechanism. Surface plasmon can further enhance the upconversion process, opening doors to many applications. However, ETU is a complex process involving competing transitions between multiple energy levels and it has been difficult to precisely determine the enhancement mechanisms. In this paper, we report a systematic study on the dynamics of the ETU process in NaYF4:Yb3+,Er3+ nanoparticles deposited on plasmonic nanograting structure. From the transient near-infrared photoluminescence under various excitation power densities, we observed faster energy transfer rates under stronger excitation conditions until it reached saturation where the highest internal upconversion efficiency was achieved. The experimental data were analyzed using the complete set of rate equations. The internal upconversion efficiency was found to be 56% and 36%, respectively, with and without the plasmonic nanograting. We also analyzed the transient green emission and found that it is determined by the infrared transition rate. To our knowledge, this is the first report of experimentally measured internal upconversion efficiency in plasmon enhanced upconversion material. Our work decouples the internal upconversion efficiency from the overall upconverted luminescence efficiency, allowing more targeted engineering for efficiency improvement. PMID:26739230

  18. (Gd,Yb,Tb)PO4 up-conversion nanocrystals for bimodal luminescence-MR imaging

    NASA Astrophysics Data System (ADS)

    Debasu, Mengistie L.; Ananias, Duarte; Pinho, Sonia L. C.; Geraldes, Carlos F. G. C.; Carlos, Luís D.; Rocha, João

    2012-07-01

    Up-conversion (Gd,Yb,Tb)PO4 materials and their potential for bimodal imaging have received little attention in the literature. Herein, we report the first study on the up-conversion emission of (Gd,Yb,Tb)PO4 nanocrystals synthesized via a hydrothermal method at 150 °C. These materials exhibit ultraviolet, blue and green up-conversion emissions upon excitation with a 980 nm continuous wave laser diode. The intensity of the blue-emission band at 479 nm, ascribed to the cooperative up-conversion emission of a pair of excited Yb3+ ions, depends on the Yb3+/Tb3+ concentration ratio, calcination temperature and particle size. Strong green up-conversion emission of Tb3+ is observed at 543 nm for the 5D4 --> 7F5 transition. Relaxometry measurements reveal that the nanocrystals are efficient T2-weighted (negative) contrast agents which, combined with visible-light emission generated by infrared excitation, affords them considerable potential for being used in bimodal, photoluminescence-magnetic resonance, imaging.Up-conversion (Gd,Yb,Tb)PO4 materials and their potential for bimodal imaging have received little attention in the literature. Herein, we report the first study on the up-conversion emission of (Gd,Yb,Tb)PO4 nanocrystals synthesized via a hydrothermal method at 150 °C. These materials exhibit ultraviolet, blue and green up-conversion emissions upon excitation with a 980 nm continuous wave laser diode. The intensity of the blue-emission band at 479 nm, ascribed to the cooperative up-conversion emission of a pair of excited Yb3+ ions, depends on the Yb3+/Tb3+ concentration ratio, calcination temperature and particle size. Strong green up-conversion emission of Tb3+ is observed at 543 nm for the 5D4 --> 7F5 transition. Relaxometry measurements reveal that the nanocrystals are efficient T2-weighted (negative) contrast agents which, combined with visible-light emission generated by infrared excitation, affords them considerable potential for being used in bimodal

  19. Low-temperature upconversion spectroscopy of nanosized Y2O3:Er,Yb phosphor

    NASA Astrophysics Data System (ADS)

    Pires, Ana Maria; Serra, Osvaldo Antonio; Heer, Stephan; Güdel, Hans Ulrich

    2005-09-01

    This work reports on the structural characterization and on the low-temperature upconversion spectroscopy of the Y2O3:2%Er,1%Yb nanophosphor prepared by thermal decomposition of a polymeric resin (Pechini's method [U.S. Patent No. 3,330,697 (July 11 1967)]). The average particle size evaluated from transmission electron microscopy lies in the range of 05-25 nm. The high-resolution upconversion luminescence spectrum at 10 K in the ultraviolet to near infrared (UV-NIR) spectral regions shows narrow lines, characteristic of Er3+ transitions occupying both Y3+ sites with point symmetries C2 and C3i in the oxide cubic system. The excitation spectrum at 10 K in the IR region was used to monitor the green upconversion and IR luminescences and it displayed Er and Yb lines. Power dependence measurements at 298 and 10 K indicate that the main upconversion mechanism is a two-photon excitation process. The temperature dependence of the upconversion luminescence shows a decrease in the emission intensity with increasing temperature, and such decrease is much more evident for the emission in the violet than in the green and the red regions.

  20. Photon energy upconversion through thermal radiation with the power efficiency reaching 16%

    NASA Astrophysics Data System (ADS)

    Wang, Junxin; Ming, Tian; Jin, Zhao; Wang, Jianfang; Sun, Ling-Dong; Yan, Chun-Hua

    2014-11-01

    The efficiency of many solar energy conversion technologies is limited by their poor response to low-energy solar photons. One way for overcoming this limitation is to develop materials and methods that can efficiently convert low-energy photons into high-energy ones. Here we show that thermal radiation is an attractive route for photon energy upconversion, with efficiencies higher than those of state-of-the-art energy transfer upconversion under continuous wave laser excitation. A maximal power upconversion efficiency of 16% is achieved on Yb3+-doped ZrO2. By examining various oxide samples doped with lanthanide or transition metal ions, we draw guidelines that materials with high melting points, low thermal conductivities and strong absorption to infrared light deliver high upconversion efficiencies. The feasibility of our upconversion approach is further demonstrated under concentrated sunlight excitation and continuous wave 976-nm laser excitation, where the upconverted white light is absorbed by Si solar cells to generate electricity and drive optical and electrical devices.

  1. Photon-phonon anti-stokes upconversion of a photonically, electronically, and thermally isolated opal

    NASA Astrophysics Data System (ADS)

    Stem, Michelle R.

    2016-05-01

    The purpose of the present research was to investigate an intense violet shift displayed by a non-toxic, natural silicate material with a highly ordered nanostructure. The material displayed an unexpected, nonlinear 2:3 photon-phonon anti-Stokes upconversion while photonically, electronically, and thermally isolated. Conducted aphotonically and at ambient temperatures, the specimen upconverted a low-power, 650 nm constant wave red laser to an internally highly dispersed 433 nm violet wavelength. The strong dispersion was largely due to nearly total internal reflection of the laser. The upconversion had an efficiency of about 78 %, based on specimen volume, with no detectable thermal variance. The 2:3 anti-Stokes upconversion displayed by this material is likely the result of a previously unknown photon-phonon evanescence response that amplified the energy of a portion of the incident laser photons. Thus, a portion of the incident laser photons were upconverted, and the material converted another portion into an amplified energy that caused the upconversion. Internal micro-lasing appeared to be a means of photon-phonon evanescent energy redistribution, enabling dispersed photonic upconversion. Additional analyses also found an unexpectedly rhythmic photonic structure in spectrophotometric scans, polariscopic color changing, and previously undocumented ultraviolet responses.

  2. Blue-emissive upconversion nanoparticles for low-power-excited bioimaging in vivo.

    PubMed

    Liu, Qian; Yang, Tianshe; Feng, Wei; Li, Fuyou

    2012-03-21

    Water-soluble upconversion luminescent (UCL) nanoparticles based on triplet-triplet annihilation (TTA) were successfully prepared by coloading sensitizer (octaethylporphyrin Pd complex) and annihilator (9,10-diphenylanthracene) into silica nanoparticles. The upconversion luminescence quantum yield of the nanoparticles can be as high as 4.5% in aqueous solution. As determined by continuous kinetic scan, the nanoparticles have excellent photostability. Such TTA-based upconversion nanoparticles show low cytotoxicity and were successfully used to label living cells with very high signal-to-noise ratio. UCL imaging with the nanoparticles as probe is capable of completely eliminating background fluorescence from either endogenous fluorophores of biological sample or the colabeled fluorescent probe. In particular, such blue-emissive upconversion nanoparticles were successfully applied in lymph node imaging in vivo of living mouse with excellent signal-to-noise ratio (>25), upon low-power density excitation of continuous-wave 532 laser (8.5 mW cm(-2)). Such high-contrast and low-power excited bioimaging in vivo with a blue-emissive upconversion nanoparticle as probe may extend the arsenal of currently available luminescent bioimaging in vitro and in vivo.

  3. An upconversion fluorescent resonant energy transfer biosensor for hepatitis B virus (HBV) DNA hybridization detection.

    PubMed

    Zhu, Hao; Lu, Feng; Wu, Xing-Cai; Zhu, Jun-Jie

    2015-11-21

    A novel fluorescent resonant energy transfer (FRET) biosensor was fabricated for the detection of hepatitis B virus (HBV) DNA using poly(ethylenimine) (PEI) modified upconversion nanoparticles (NH2-UCNPs) as energy donor and gold nanoparticles (Au NPs) as acceptor. The PEI modified upconversion nanoparticles were prepared directly with a simple one-pot hydrothermal method, which provides high quality amino-group functionalized UCNPs with uniform morphology and strong upconversion luminescence. Two single-stranded DNA strands, which were partially complementary to each other, were then conjugated with NH2-UCNPs and Au NPs. When DNA conjugated NH2-UCNPs and Au NPs are mixed together, the hybridization between complementary DNA sequences on UCNPs and Au NPs will lead to the quenching of the upconversion luminescence due to the FRET process. Meanwhile, upon the addition of target DNA, Au NPs will leave the surface of the UCNPs and the upconversion luminescence can be restored because of the formation of the more stable double-stranded DNA on the UCNPs. The sensor we fabricated here for target DNA detection shows good sensitivity and high selectivity, which has the potential for clinical applications in the analysis of HBV and other DNA sequences. PMID:26421323

  4. Photon energy upconversion through thermal radiation with the power efficiency reaching 16%.

    PubMed

    Wang, Junxin; Ming, Tian; Jin, Zhao; Wang, Jianfang; Sun, Ling-Dong; Yan, Chun-Hua

    2014-11-28

    The efficiency of many solar energy conversion technologies is limited by their poor response to low-energy solar photons. One way for overcoming this limitation is to develop materials and methods that can efficiently convert low-energy photons into high-energy ones. Here we show that thermal radiation is an attractive route for photon energy upconversion, with efficiencies higher than those of state-of-the-art energy transfer upconversion under continuous wave laser excitation. A maximal power upconversion efficiency of 16% is achieved on Yb(3+)-doped ZrO2. By examining various oxide samples doped with lanthanide or transition metal ions, we draw guidelines that materials with high melting points, low thermal conductivities and strong absorption to infrared light deliver high upconversion efficiencies. The feasibility of our upconversion approach is further demonstrated under concentrated sunlight excitation and continuous wave 976-nm laser excitation, where the upconverted white light is absorbed by Si solar cells to generate electricity and drive optical and electrical devices.

  5. Photon energy upconversion through thermal radiation with the power efficiency reaching 16%.

    PubMed

    Wang, Junxin; Ming, Tian; Jin, Zhao; Wang, Jianfang; Sun, Ling-Dong; Yan, Chun-Hua

    2014-01-01

    The efficiency of many solar energy conversion technologies is limited by their poor response to low-energy solar photons. One way for overcoming this limitation is to develop materials and methods that can efficiently convert low-energy photons into high-energy ones. Here we show that thermal radiation is an attractive route for photon energy upconversion, with efficiencies higher than those of state-of-the-art energy transfer upconversion under continuous wave laser excitation. A maximal power upconversion efficiency of 16% is achieved on Yb(3+)-doped ZrO2. By examining various oxide samples doped with lanthanide or transition metal ions, we draw guidelines that materials with high melting points, low thermal conductivities and strong absorption to infrared light deliver high upconversion efficiencies. The feasibility of our upconversion approach is further demonstrated under concentrated sunlight excitation and continuous wave 976-nm laser excitation, where the upconverted white light is absorbed by Si solar cells to generate electricity and drive optical and electrical devices. PMID:25430519

  6. Up-conversion luminescence and optical temperature sensing behaviour of Yb3+/Er3+ codoped CaWO4 material

    NASA Astrophysics Data System (ADS)

    Cheng, Xuerui; Yang, Kun; Wang, Jiankun; Yang, Linfu; Cheng, Xiaoshuai

    2016-08-01

    Present article report on structural and optical properties of Er3+/Yb3+ codoped CaWO4 phosphors. Structural properties are explored using XRD and Raman technologies. The upconversion emission has been investigated with 980 nm excitation. The upconversion emission intensity is dependent on the concentrations of Yb3+ ions and reaches a maximum at 7%. Logarithmic plots of power dependencies reveal that the green and red emissions originate from a two-photon upconversion process. Based on the photon energy and the emission spectra, the possible upconversion processes and emission mechanisms are discussed. Finally, the optical temperature sensing properties has been performed using the fluorescence intensity ratio technique based on green upconversion emissions. Its temperature sensitivity is found to be above 0.0025 K-1 in the whole temperature range of 300-540 K, revealing this phosphor to be a promising optical temperature sensing material.

  7. Polarization-dependent extraordinary optical transmission from upconversion nanoparticles

    NASA Astrophysics Data System (ADS)

    Wang, Peng Hui; Salcedo, Walter J.; Pichaandi, Jothirmayanantham; van Veggel, Frank C. J. M.; Brolo, Alexandre G.

    2015-10-01

    Enhanced upconversion (UC) emission was experimentally demonstrated using gold double antenna nanoparticles coupled to nanoslits in gold films. The transmitted red emission from UC ytterbium and erbium co-doped sodium yttrium fluoride (NaYF4:Yb3+/Er3+) nanoparticles (UC NPs) at ~665 nm (excited with a 980 nm diode laser) was enhanced relative to the green emission at ~550 nm. The relatively enhanced UC NP emission could be tuned by the different polarization-dependent extraordinary optical transmission modes coupled to the gold nanostructures. Finite-difference time-domain calculations suggest that the preferential enhanced UC emission is related to a combination of different surface plasmon mode excitation coupling to cavity Fabry-Perot interactions. A maximum UC enhancement of 6-fold was measured for nanoslit arrays in the absence of the double antennas. In the presence of the double nanoantennas inside the nanoslits, the UC enhancement was between 2- and 4-fold, depending on the experimental conditions.Enhanced upconversion (UC) emission was experimentally demonstrated using gold double antenna nanoparticles coupled to nanoslits in gold films. The transmitted red emission from UC ytterbium and erbium co-doped sodium yttrium fluoride (NaYF4:Yb3+/Er3+) nanoparticles (UC NPs) at ~665 nm (excited with a 980 nm diode laser) was enhanced relative to the green emission at ~550 nm. The relatively enhanced UC NP emission could be tuned by the different polarization-dependent extraordinary optical transmission modes coupled to the gold nanostructures. Finite-difference time-domain calculations suggest that the preferential enhanced UC emission is related to a combination of different surface plasmon mode excitation coupling to cavity Fabry-Perot interactions. A maximum UC enhancement of 6-fold was measured for nanoslit arrays in the absence of the double antennas. In the presence of the double nanoantennas inside the nanoslits, the UC enhancement was between 2- and 4-fold

  8. Upconversion luminescence and blackbody radiation in tetragonal YSZ co-doped with Tm(3+) and Yb(3+).

    PubMed

    Soares, M R N; Ferro, M; Costa, F M; Monteiro, T

    2015-12-21

    Lanthanide doped inorganic nanoparticles with upconversion luminescence are of utmost importance for biomedical applications, solid state lighting and photovoltaics. In this work we studied the downshifted luminescence, upconversion luminescence (UCL) and blackbody radiation of tetragonal yttrium stabilized zirconia co-doped with Tm(3+) and Yb(3+) single crystals and nanoparticles produced by laser floating zone and laser ablation in liquids, respectively. The photoluminescence (PL) and PL excitation (PLE) were investigated at room temperature (RT). PL spectra exhibit the characteristic lines in UV, blue/green, red and NIR regions of the Tm(3+) (4f(12)) under resonant excitation into the high energy (2S+1)LJ multiplets. Under NIR excitation (980 nm), the samples placed in air display an intense NIR at ∼800 nm due to the (1)G4→(3)H5/(3)H4→(3)H6 transitions. Additionally, red, blue/green and ultraviolet UCL is observed arising from higher excited (1)G4 and (1)D2 multiplets. The power excitation dependence of the UCL intensity indicated that 2-3 low energy absorbed photons are involved in the UCL for low power levels, while for high powers, the identified saturation is dependent on the material size with a enhanced effect on the NPs. The temperature dependence of the UCL was investigated for single crystals and targets used in the ablation. An overall increase of the integrated intensity was found to occur between 12 K and the RT. The thermally activated process is described by activation energies of 10 meV and 30 meV for single crystals and targets, respectively. For the NPs, the UCL was found to be strongly sensitive to pressure conditions. Under vacuum conditions, instead of the narrow lines of the Tm(3+), a wide blackbody radiation was detected, responsible for the change in the emission colour from blue to orange. This phenomenon is totally reversible when the NPs are placed at ambient pressure. The UCL/blackbody radiation in the nanosized material exhibits

  9. Upconversion luminescence and blackbody radiation in tetragonal YSZ co-doped with Tm3+ and Yb3+

    NASA Astrophysics Data System (ADS)

    Soares, M. R. N.; Ferro, M.; Costa, F. M.; Monteiro, T.

    2015-11-01

    Lanthanide doped inorganic nanoparticles with upconversion luminescence are of utmost importance for biomedical applications, solid state lighting and photovoltaics. In this work we studied the downshifted luminescence, upconversion luminescence (UCL) and blackbody radiation of tetragonal yttrium stabilized zirconia co-doped with Tm3+ and Yb3+ single crystals and nanoparticles produced by laser floating zone and laser ablation in liquids, respectively. The photoluminescence (PL) and PL excitation (PLE) were investigated at room temperature (RT). PL spectra exhibit the characteristic lines in UV, blue/green, red and NIR regions of the Tm3+ (4f12) under resonant excitation into the high energy 2S+1LJ multiplets. Under NIR excitation (980 nm), the samples placed in air display an intense NIR at ~800 nm due to the 1G4 --> 3H5/3H4 --> 3H6 transitions. Additionally, red, blue/green and ultraviolet UCL is observed arising from higher excited 1G4 and 1D2 multiplets. The power excitation dependence of the UCL intensity indicated that 2-3 low energy absorbed photons are involved in the UCL for low power levels, while for high powers, the identified saturation is dependent on the material size with a enhanced effect on the NPs. The temperature dependence of the UCL was investigated for single crystals and targets used in the ablation. An overall increase of the integrated intensity was found to occur between 12 K and the RT. The thermally activated process is described by activation energies of 10 meV and 30 meV for single crystals and targets, respectively. For the NPs, the UCL was found to be strongly sensitive to pressure conditions. Under vacuum conditions, instead of the narrow lines of the Tm3+, a wide blackbody radiation was detected, responsible for the change in the emission colour from blue to orange. This phenomenon is totally reversible when the NPs are placed at ambient pressure. The UCL/blackbody radiation in the nanosized material exhibits non-contact pressure

  10. Brady 1D seismic velocity model ambient noise prelim

    DOE Data Explorer

    Mellors, Robert J.

    2013-10-25

    Preliminary 1D seismic velocity model derived from ambient noise correlation. 28 Green's functions filtered between 4-10 Hz for Vp, Vs, and Qs were calculated. 1D model estimated for each path. The final model is a median of the individual models. Resolution is best for the top 1 km. Poorly constrained with increasing depth.

  11. Solid state photon upconversion utilizing thermally activated delayed fluorescence molecules as triplet sensitizer

    SciTech Connect

    Wu, Tony C.; Congreve, Daniel N.; Baldo, Marc A.

    2015-07-20

    The ability to upconvert light is useful for a range of applications, from biological imaging to solar cells. But modern technologies have struggled to upconvert incoherent incident light at low intensities. Here, we report solid state photon upconversion employing triplet-triplet exciton annihilation in an organic semiconductor, sensitized by a thermally activated-delayed fluorescence (TADF) dye. Compared to conventional phosphorescent sensitizers, the TADF dye maximizes the wavelength shift in upconversion due to its small singlet-triplet splitting. The efficiency of energy transfer from the TADF dye is 9.1%, and the conversion yield of sensitizer exciton pairs to singlet excitons in the annihilator is 1.1%. Our results demonstrate upconversion in solid state geometries and with non-heavy metal-based sensitizer materials.

  12. Paper-based upconversion fluorescence resonance energy transfer biosensor for sensitive detection of multiple cancer biomarkers

    PubMed Central

    Xu, Sai; Dong, Biao; Zhou, Donglei; Yin, Ze; Cui, Shaobo; Xu, Wen; Chen, Baojiu; Song, Hongwei

    2016-01-01

    A paper-based upconversion fluorescence resonance energy transfer assay device is proposed for sensitive detection of CEA. The device is fabricated on a normal filter paper with simple nano-printing method. Upconversion nanoparticles tagged with specific antibodies are printed to the test zones on the test paper, followed by the introduction of assay antigen. Upconversion fluorescence measurements are directly conducted on the test zones after the antigen-to-antibody reactions. Furthermore, a multi-channel test paper for simultaneous detection of multiple cancer biomarkers was established by the same method and obtained positive results. The device showed high anti-interfere, stability, reproducible and low detection limit (0.89 ng/mL), moreover it is very easy to fabricate and operate, which is a promising prospect for a clinical point-of-care test. PMID:27001460

  13. Fluorescence upconversion properties of a class of improved pyridinium dyes induced by two-photon absorption

    NASA Astrophysics Data System (ADS)

    Xu, Guibao; Hu, Dawei; Zhao, Xian; Shao, Zongshu; Liu, Huijun; Tian, Yupeng

    2007-06-01

    We report the fluorescence upconversion properties of a class of improved pyridinium toluene- p-sulfonates having donor- π-acceptor (D- π-A) structure under two-photon excitation at 1064 nm. The experimental results show that both the two-photon excited (TPE) fluorescence lifetime and the two-photon pumped (TPP) energy upconversion efficiency were increased with the enhancement of electron-donating capability of the donor in the molecule. It is also indicated that an overlong alkyl group tends to result in a weakened molecular conjugation, leading to a decreased two-photon absorption (TPA) cross section. By choosing the donor, we can obtain a longest fluorescence lifetime of 837 ps, a highest energy upconversion efficiency of ˜6.1%, and a maximum TPA cross-section of 8.74×10 -48 cm 4 s/photon in these dyes.

  14. Up-conversion in rare earth-doped silica hollow spheres

    NASA Astrophysics Data System (ADS)

    Fortes, Luís M.; Li, Yigang; Réfega, Ricardo; Clara Gonçalves, M.

    2012-06-01

    In the present work, Er/Yb co-doped silica hollow spheres are prepared in a two-step process. In a first step, polystyrene-core is silica coated in situ by a modified Stöber sol-gel method and in the second one, the sacrificial polystyrene core is thermally removed. The core-shell and the hollow spheres are characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and photoluminescence spectroscopy (PL). PL measurements show up-conversion phenomena upon excitation at 975 nm, through the emission of blue (˜490 nm), green (˜523 nm and ˜536 nm) and red (˜655 nm) light. The up-conversion phenomena are discussed and modelled. The developed model explains the up-conversion phenomena of Er/Yb co-doped silica hollow spheres, with special agreement for high Yb/Er ratio.

  15. General synthesis route to fabricate uniform upconversion luminescent gadolinium oxide hollow spheres.

    PubMed

    Jia, Guang; Zhang, Cuimiao; Ding, Shiwen; Wang, Liyong

    2011-08-01

    Uniform upconversion luminescent gadolinium oxide hollow spheres were successfully synthesized via a homogeneous precipitation method with carbon spheres as template followed by a calcination process. During the annealing process, the carbon spheres template can be effectively removed and the amorphous precursor has converted to crystalline Gd2O3, which can be confirmed by the XRD and TG-DSC analysis. SEM and TEM images indicate that the Gd2O3 hollow spheres with diameters of 300-400 nm are uniform in size and distribution. The rare earth activator ions Ln3+-doped Gd2O3 hollow spheres exhibit intense upconversion luminescence with different colors under 980 nm light excitation, which may find potential applications in the fields such as drug delivery or biological labeling. Moreover, the upconversion luminescent mechanisms of the hollow spherical phosphors were investigated in detail.

  16. Phase closure retrieval in an infrared-to-visible upconversion interferometer for high resolution astronomical imaging.

    PubMed

    Ceus, Damien; Tonello, Alessandro; Grossard, Ludovic; Delage, Laurent; Reynaud, François; Herrmann, Harald; Sohler, Wolfgang

    2011-04-25

    This paper demonstrates the use of a nonlinear upconversion process to observe an infrared source through a telescope array detecting the interferometric signal in the visible domain. We experimentally demonstrate the possibility to retrieve information on the phase of the object spectrum of an infrared source by using a three-arm upconversion interferometer. We focus our study on the acquisition of phase information of the complex visibility by means of the phase closure technique. In our experimental demonstration, a laboratory binary star with an adjustable photometric ratio is used as a test source. A real time comparison between a standard three-arm interferometer and our new concept using upconversion by sum-frequency generation demonstrates the preservation of phase information which is essential for image reconstruction.

  17. Tailoring Plasmonic Enhanced Upconversion in Single NaYF4:Yb3+/Er3+ Nanocrystals

    PubMed Central

    Wang, Ya-Lan; Mohammadi Estakhri, Nasim; Johnson, Amber; Li, Hai-Yang; Xu, Li-Xiang; Zhang, Zhenyu; Alù, Andrea; Wang, Qu-Quan; Shih, Chih-Kang (Ken)

    2015-01-01

    By using silver nanoplatelets with a widely tunable localized surface plasmon resonance (LSPR), and their corresponding local field enhancement, here we show large manipulation of plasmonic enhanced upconversion in NaYF4:Yb3+/Er3+ nanocrystals at the single particle level. In particular, we show that when the plasmonic resonance of silver nanolplatelets is tuned to 656 nm, matching the emission wavelength, an upconversion enhancement factor ~5 is obtained. However, when the plasmonic resonance is tuned to 980 nm, matching the nanocrystal absorption wavelength, we achieve an enhancement factor of ~22 folds. The precise geometric arrangement between fluorescent nanoparticles and silver nanoplatelets allows us to make, for the first time, a comparative analysis between experimental results and numerical simulations, yielding a quantitative agreement at the single particle level. Such a comparison lays the foundations for a rational design of hybrid metal-fluorescent nanocrystals to harness the upconversion enhancement for biosensing and light harvesting applications. PMID:25976870

  18. Triplet-triplet annihilation photon-upconversion: towards solar energy applications.

    PubMed

    Gray, Victor; Dzebo, Damir; Abrahamsson, Maria; Albinsson, Bo; Moth-Poulsen, Kasper

    2014-06-14

    Solar power production and solar energy storage are important research areas for development of technologies that can facilitate a transition to a future society independent of fossil fuel based energy sources. Devices for direct conversion of solar photons suffer from poor efficiencies due to spectrum losses, which are caused by energy mismatch between the optical absorption of the devices and the broadband irradiation provided by the sun. In this context, photon-upconversion technologies are becoming increasingly interesting since they might offer an efficient way of converting low energy solar energy photons into higher energy photons, ideal for solar power production and solar energy storage. This perspective discusses recent progress in triplet-triplet annihilation (TTA) photon-upconversion systems and devices for solar energy applications. Furthermore, challenges with evaluation of the efficiency of TTA-photon-upconversion systems are discussed and a general approach for evaluation and comparison of existing systems is suggested.

  19. Single-band upconversion nanoprobes for multiplexed simultaneous in situ molecular mapping of cancer biomarkers

    PubMed Central

    Zhou, Lei; Wang, Rui; Yao, Chi; Li, Xiaomin; Wang, Chengli; Zhang, Xiaoyan; Xu, Congjian; Zeng, Aijun; Zhao, Dongyuan; Zhang, Fan

    2015-01-01

    The identification of potential diagnostic markers and target molecules among the plethora of tumour oncoproteins for cancer diagnosis requires facile technology that is capable of quantitatively analysing multiple biomarkers in tumour cells and tissues. Diagnostic and prognostic classifications of human tumours are currently based on the western blotting and single-colour immunohistochemical methods that are not suitable for multiplexed detection. Herein, we report a general and novel method to prepare single-band upconversion nanoparticles with different colours. The expression levels of three biomarkers in breast cancer cells were determined using single-band upconversion nanoparticles, western blotting and immunohistochemical technologies with excellent correlation. Significantly, the application of antibody-conjugated single-band upconversion nanoparticle molecular profiling technology can achieve the multiplexed simultaneous in situ biodetection of biomarkers in breast cancer cells and tissue specimens and produce more accurate results for the simultaneous quantification of proteins present at low levels compared with classical immunohistochemical technology. PMID:25907226

  20. Realizing up-conversion fluorescence tuning in lanthanide-doped nanocrystals by femtosecond pulse shaping method

    PubMed Central

    Zhang, Shian; Yao, Yunhua; Shuwu, Xu; Liu, Pei; Ding, Jingxin; Jia, Tianqing; Qiu, Jianrong; Sun, Zhenrong

    2015-01-01

    The ability to tune color output of nanomaterials is very important for their applications in laser, optoelectronic device, color display and multiplexed biolabeling. Here we first propose a femtosecond pulse shaping technique to realize the up-conversion fluorescence tuning in lanthanide-doped nanocrystals dispersed in the glass. The multiple subpulse formation by a square phase modulation can create different excitation pathways for various up-conversion fluorescence generations. By properly controlling these excitation pathways, the multicolor up-conversion fluorescence can be finely tuned. This color tuning by the femtosecond pulse shaping technique is realized in single material by single-color laser field, which is highly desirable for further applications of the lanthanide-doped nanocrystals. This femtosecond pulse shaping technique opens an opportunity to tune the color output in the lanthanide-doped nanocrystals, which may bring a new revolution in the control of luminescence properties of nanomaterials. PMID:26290391

  1. Analysis of upconversion processes in germanate and tellurite glasses codoped with Yb3+/Ho3+

    NASA Astrophysics Data System (ADS)

    Iwanowicz, Kamil; Ragiń, Tomasz; Wyrwas, Marek; Żmojda, Jacek; Kochanowicz, Marcin; Dorosz, Dominik; Dorosz, Jan

    In this paper the analysis of upconversion luminescence dynamics in tellurite and germanate glasses doped with Ho3+ and sensitized by Yb3+ in 8:1 molar ratio was presented. Population of energy levels was calculated using Runge-Kutta method. The influence of pump power (976 nm) radiation on population of excited levels and the possible upconversion mechanisms were analyzed. The energy transfer coefficient in tellurite glass CD2 = 5,0 x 10-18 cm3/s, CD3 = 1,5 x 10-17 cm3/s and CD4 = 9,0 x 10-17 cm3/s and in germanate glass CD2 = 2,80 x 10-18 cm3/s, CD3 = 6,35 x 10-18 cm cm3/s and CD4 = 3,56 x 10-17 cm3/s were used to analyze dynamics of upconversion processes.

  2. Single-band upconversion nanoprobes for multiplexed simultaneous in situ molecular mapping of cancer biomarkers

    NASA Astrophysics Data System (ADS)

    Zhou, Lei; Wang, Rui; Yao, Chi; Li, Xiaomin; Wang, Chengli; Zhang, Xiaoyan; Xu, Congjian; Zeng, Aijun; Zhao, Dongyuan; Zhang, Fan

    2015-04-01

    The identification of potential diagnostic markers and target molecules among the plethora of tumour oncoproteins for cancer diagnosis requires facile technology that is capable of quantitatively analysing multiple biomarkers in tumour cells and tissues. Diagnostic and prognostic classifications of human tumours are currently based on the western blotting and single-colour immunohistochemical methods that are not suitable for multiplexed detection. Herein, we report a general and novel method to prepare single-band upconversion nanoparticles with different colours. The expression levels of three biomarkers in breast cancer cells were determined using single-band upconversion nanoparticles, western blotting and immunohistochemical technologies with excellent correlation. Significantly, the application of antibody-conjugated single-band upconversion nanoparticle molecular profiling technology can achieve the multiplexed simultaneous in situ biodetection of biomarkers in breast cancer cells and tissue specimens and produce more accurate results for the simultaneous quantification of proteins present at low levels compared with classical immunohistochemical technology.

  3. Nonlinear spectral and lifetime management in upconversion nanoparticles by controlling energy distribution.

    PubMed

    Wang, Yu; Deng, Renren; Xie, Xiaoji; Huang, Ling; Liu, Xiaogang

    2016-03-28

    Optical tuning of lanthanide-doped upconversion nanoparticles has attracted considerable attention over the past decade because this development allows the advance of new frontiers in energy conversion, materials science, and biological imaging. Here we present a rational approach to manipulating the spectral profile and lifetime of lanthanide emission in upconversion nanoparticles by tailoring their nonlinear optical properties. We demonstrate that the incorporation of energy distributors, such as surface defects or an extra amount of dopants, into a rare-earth-based host lattice alters the decay behavior of excited sensitizers, thus markedly improving the emitters' sensitivity to excitation power. This work provides insight into mechanistic understanding of upconversion phenomena in nanoparticles and also enables exciting new opportunities of using these nanomaterials for photonic applications.

  4. Quantitative Imaging of Single Upconversion Nanoparticles in Biological Tissue

    PubMed Central

    Nadort, Annemarie; Sreenivasan, Varun K. A.; Song, Zhen; Grebenik, Ekaterina A.; Nechaev, Andrei V.; Semchishen, Vladimir A.; Panchenko, Vladislav Y.; Zvyagin, Andrei V.

    2013-01-01

    The unique luminescent properties of new-generation synthetic nanomaterials, upconversion nanoparticles (UCNPs), enabled high-contrast optical biomedical imaging by suppressing the crowded background of biological tissue autofluorescence and evading high tissue absorption. This raised high expectations on the UCNP utilities for intracellular and deep tissue imaging, such as whole animal imaging. At the same time, the critical nonlinear dependence of the UCNP luminescence on the excitation intensity results in dramatic signal reduction at (∼1 cm) depth in biological tissue. Here, we report on the experimental and theoretical investigation of this trade-off aiming at the identification of optimal application niches of UCNPs e.g. biological liquids and subsurface tissue layers. As an example of such applications, we report on single UCNP imaging through a layer of hemolyzed blood. To extend this result towards in vivo applications, we quantified the optical properties of single UCNPs and theoretically analyzed the prospects of single-particle detectability in live scattering and absorbing bio-tissue using a human skin model. The model predicts that a single 70-nm UCNP would be detectable at skin depths up to 400 µm, unlike a hardly detectable single fluorescent (fluorescein) dye molecule. UCNP-assisted imaging in the ballistic regime thus allows for excellent applications niches, where high sensitivity is the key requirement. PMID:23691012

  5. Near-infrared (NIR) up-conversion optogenetics.

    PubMed

    Hososhima, Shoko; Yuasa, Hideya; Ishizuka, Toru; Hoque, Mohammad Razuanul; Yamashita, Takayuki; Yamanaka, Akihiro; Sugano, Eriko; Tomita, Hiroshi; Yawo, Hiromu

    2015-01-01

    Non-invasive remote control technologies designed to manipulate neural functions have been long-awaited for the comprehensive and quantitative understanding of neuronal network in the brain as well as for the therapy of neurological disorders. Recently, it has become possible for the neuronal activity to be optically manipulated using biological photo-reactive molecules such as channelrhodopsin (ChR)-2. However, ChR2 and its relatives are mostly reactive to visible light, which does not effectively penetrate through biological tissues. In contrast, near-infrared (NIR) light (650-1450 nm) penetrates deep into the tissues because biological systems are almost transparent to light within this so-called 'imaging window'. Here we used lanthanide nanoparticles (LNPs), composed of rare-earth elements, as luminous bodies to activate ChRs since they absorb low-energy NIR light to emit high-energy visible light (up-conversion). Here, we created a new type of optogenetic system which consists of the donor LNPs and the acceptor ChRs. The NIR laser irradiation emitted visible light from LNPs, then induced the photo-reactive responses in the near-by cells that expressed ChRs. However, there remains room for large improvements in the energy efficiency of the LNP-ChR system. PMID:26552717

  6. Upconversion Nanoparticles for Photodynamic Therapy and Other Cancer Therapeutics

    PubMed Central

    Wang, Chao; Cheng, Liang; Liu, Zhuang

    2013-01-01

    Photodynamic therapy (PDT) is a non-invasive treatment modality for a variety of diseases including cancer. PDT based on upconversion nanoparticles (UCNPs) has received much attention in recent years. Under near-infrared (NIR) light excitation, UCNPs are able to emit high-energy visible light, which can activate surrounding photosensitizer (PS) molecules to produce singlet oxygen and kill cancer cells. Owing to the high tissue penetration ability of NIR light, NIR-excited UCNPs can be used to activate PS molecules in much deeper tissues compared to traditional PDT induced by visible or ultraviolet (UV) light. In addition to the application of UCNPs as an energy donor in PDT, via similar mechanisms, they could also be used for the NIR light-triggered drug release or activation of 'caged' imaging or therapeutic molecules. In this review, we will summarize the latest progresses regarding the applications of UCNPs for photodynamic therapy, NIR triggered drug and gene delivery, as well as several other UCNP-based cancer therapeutic approaches. The future prospects and challenges in this emerging field will be also discussed. PMID:23650479

  7. Riboflavin photoactivation by upconversion nanoparticles for cancer treatment

    PubMed Central

    Khaydukov, E. V.; Mironova, K. E.; Semchishen, V. A.; Generalova, A. N.; Nechaev, A. V.; Khochenkov, D. A.; Stepanova, E. V.; Lebedev, O. I.; Zvyagin, A. V.; Deyev, S. M.; Panchenko, V. Ya.

    2016-01-01

    Riboflavin (Rf) is a vitamin and endogenous photosensitizer capable to generate reactive oxygen species (ROS) under UV-blue irradiation and kill cancer cells, which are characterized by the enhanced uptake of Rf. We confirmed its phototoxicity on human breast adenocarcinoma cells SK-BR-3 preincubated with 30-μM Rf and irradiated with ultraviolet light, and proved that such Rf concentrations (60 μM) are attainable in vivo in tumour site by systemic intravascular injection. In order to extend the Rf photosensitization depth in cancer tissue to 6 mm in depth, we purpose-designed core/shell upconversion nanoparticles (UCNPs, NaYF4:Yb3+:Tm3+/NaYF4) capable to convert 2% of the deeply-penetrating excitation at 975 nm to ultraviolet-blue power. This power was expended to photosensitise Rf and kill SK-BR-3 cells preincubated with UCNPs and Rf, where the UCNP-Rf energy transfer was photon-mediated with ~14% Förster process contribution. SK-BR-3 xenograft regression in mice was observed for 50 days, following the Rf-UCNPs peritumoural injection and near-infrared light photodynamic treatment of the lesions. PMID:27731350

  8. Basic understanding of the lanthanide related upconversion emissions

    NASA Astrophysics Data System (ADS)

    Dong, Hao; Sun, Ling-Dong; Yan, Chun-Hua

    2013-06-01

    With abundant energy levels of 4f electron configurations, trivalent lanthanide ions (Ln3+) are endowed with unique and fascinating luminescent properties. Inheriting the native transition behaviour of the lanthanide ions, Ln3+ based nanomaterials have aroused great interest for a wide range of applications, including lighting and displays, optical fibers and amplifiers, responsive luminescent stains for biomedical analysis, in vivo and in vitro imaging, and enhancement for silicon solar cell devices. It should be noted that the application depends completely on the corresponding luminescent behaviour. To deepen the understanding of the luminescent mechanism is important for the developing of the field and the design of new Ln3+ based luminescent materials toward applications. In this review, we focused mainly on the recent developments on upconversion (UC) emission studies. Firstly, the emphasis was put on the introduction of basic luminescent properties of Ln3+ with f-f transitions, and then the corresponding mechanisms and properties of UC emission were discussed in detail, the potential researches with respect to UC mechanisms and properties were finally outlined.

  9. Bioapplications and biotechnologies of upconversion nanoparticle-based nanosensors.

    PubMed

    Wang, Chengli; Li, Xiaomin; Zhang, Fan

    2016-06-21

    Upconversion nanoparticles (UCNPs), which can emit ultraviolet/visible (UV/Vis) light under near-infrared (NIR) excitation, are regarded as a new generation of nanoprobes because of their unique optical properties, including a virtually zero auto-fluorescence background for the improved signal-to-noise ratio, narrow emission bandwidths and high resistance to photo-bleaching. These properties make UCNPs promising candidates as luminescent bioprobes in biomedicine and biotechnology. In this review, we focus on the recent progress in the development of UCNP-based nanoprobes for biosensing. Firstly, as the FRET process is a widely used method for biosensing to improve the sensitivity, we summarize recent research studies about UCNP-based nanocomposites utilizing the FRET process for biosensing. Different energy acceptors (organic dyes, noble metal nanoparticles, carbon nanomaterials and semiconductor nanomaterials) with their own advantages and limitations are well summarized in this review. Secondly, since UCNPs have been utilized for the detection of different kinds of analytes, we introduce recent research studies about UCNPs for ions, gas molecules, biomolecules and thermal sensing. Finally, we highlight the typical detection techniques and UCNP based devices for bioapplications.

  10. Core - shell upconversion nanoparticle - semiconductor heterostructures for photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Dou, Qing Qing; Rengaramchandran, Adith; Selvan, Subramanian Tamil; Paulmurugan, Ramasamy; Zhang, Yong

    2015-02-01

    Core-shell nanoparticles (CSNPs) with diverse chemical compositions have been attracting greater attention in recent years. However, it has been a challenge to develop CSNPs with different crystal structures due to the lattice mismatch of the nanocrystals. Here we report a rational design of core-shell heterostructure consisting of NaYF4:Yb,Tm upconversion nanoparticle (UCN) as the core and ZnO semiconductor as the shell for potential application in photodynamic therapy (PDT). The core-shell architecture (confirmed by TEM and STEM) enables for improving the loading efficiency of photosensitizer (ZnO) as the semiconductor is directly coated on the UCN core. Importantly, UCN acts as a transducer to sensitize ZnO and trigger the generation of cytotoxic reactive oxygen species (ROS) to induce cancer cell death. We also present a firefly luciferase (FLuc) reporter gene based molecular biosensor (ARE-FLuc) to measure the antioxidant signaling response activated in cells during the release of ROS in response to the exposure of CSNPs under 980 nm NIR light. The breast cancer cells (MDA-MB-231 and 4T1) exposed to CSNPs showed significant release of ROS as measured by aminophenyl fluorescein (APF) and ARE-FLuc luciferase assays, and ~45% cancer cell death as measured by MTT assay, when illuminated with 980 nm NIR light.

  11. Sensing Using Rare-Earth-Doped Upconversion Nanoparticles

    PubMed Central

    Hao, Shuwei; Chen, Guanying; Yang, Chunhui

    2013-01-01

    Optical sensing plays an important role in theranostics due to its capability to detect hint biochemical entities or molecular targets as well as to precisely monitor specific fundamental psychological processes. Rare-earth (RE) doped upconversion nanoparticles (UCNPs) are promising for these endeavors due to their unique frequency converting capability; they emit efficient and sharp visible or ultraviolet (UV) luminescence via use of ladder-like energy levels of RE ions when excited at near infrared (NIR) light that are silent to tissues. These features allow not only a high penetration depth in biological tissues but also a high detection sensitivity. Indeed, the energy transfer between UCNPs and biomolecular or chemical indicators provide opportunities for high-sensitive bio- and chemical-sensing. A temperature-sensitive change of the intensity ratio between two close UC bands promises them for use in temperature mapping of a single living cell. In this work, we review recent investigations on using UCNPs for the detection of biomolecules (avidin, ATP, etc.), ions (cyanide, mecury, etc.), small gas molecules (oxygen, carbon dioxide, ammonia, etc.), as well as for in vitro temperature sensing. We also briefly summarize chemical methods in synthesizing UCNPs of high efficiency that are important for the detection limit. PMID:23650480

  12. Specific Visualization of Tumor Cells Using Upconversion Nanophosphors

    PubMed Central

    Grebenik, E. A.; Generalova, A. N.; Nechaev, A. V.; Khaydukov, E.V.; Mironova, K. E.; Stremovskiy, O. A.; Lebedenko, E.N.; Zvyagin, A. V.; Deyev, S. M.

    2014-01-01

    The development of targeted constructs on the basis of photoluminescent nanoparticles with a high photo- and chemical stability and absorption/emission spectra in the “transparency window” of biological tissues is an important focus area of present-day medical diagnostics. In this work, a targeted two-component construct on the basis of upconversion nanophosphors (UCNPs) and anti-tumor 4D5 scFv was developed for selective labeling of tumor cells overexpressing the HER2 tumor marker characteristic of a number of human malignant tumors. A high affinity barnase : barstar (Bn : Bs) protein pair, which exhibits high stability in a wide range of pH and temperatures, was exploited as a molecular adapter providing self-assembly of the two-component construct. High selectivity for the binding of the two-component 4D5 scFv-Bn : UCNP-Bs construct to human breast adenocarcinoma SK-BR-3 cells overexpressing HER2 was demonstrated. This approach provides an opportunity to produce similar constructs for the visualization of different specific markers in pathogenic tissues, including malignant tumors. PMID:25558394

  13. Upconversion fluorescent strip sensor for rapid determination of Vibrio anguillarum

    NASA Astrophysics Data System (ADS)

    Zhao, Peng; Wu, Yuanyuan; Zhu, Yihua; Yang, Xiaoling; Jiang, Xin; Xiao, Jingfan; Zhang, Yuanxing; Li, Chunzhong

    2014-03-01

    Here, we report a simple and ultrasensitive upconversion fluorescent strip sensor based on NaYF4:Yb,Er nanoparticles (NPs) and the lateral flow immunochromatographic assay (LFIA). Carboxyl-modified β-NaYF4:Yb,Er NPs were successfully synthesized by a facile one-pot solvothermal approach, upon further coupling with monoclonal antibody, the resultant UCNPs-antibody conjugates probes were used in LFIA and served as signal vehicles for the fluorescent reporters. V. anguillarum was used as a model analyte to demonstrate the use of this strip sensor. The limit of the detection for the fluorescent strip was determined as 102 CFU mL-1, which is 100 times lower than those displayed by enzyme-linked immunosorbent assays, while the time needed for the detection was only 15 min. Furthermore, no cross-reaction with other eight pathogens was found, indicating the good specificity of the strip. This developed LFIA would offer the potential as a useful tool for the quantification of pathogens analysis in the future.

  14. Core-shell upconversion nanoparticle - semiconductor heterostructures for photodynamic therapy.

    PubMed

    Dou, Qing Qing; Rengaramchandran, Adith; Selvan, Subramanian Tamil; Paulmurugan, Ramasamy; Zhang, Yong

    2015-01-01

    Core-shell nanoparticles (CSNPs) with diverse chemical compositions have been attracting greater attention in recent years. However, it has been a challenge to develop CSNPs with different crystal structures due to the lattice mismatch of the nanocrystals. Here we report a rational design of core-shell heterostructure consisting of NaYF4:Yb,Tm upconversion nanoparticle (UCN) as the core and ZnO semiconductor as the shell for potential application in photodynamic therapy (PDT). The core-shell architecture (confirmed by TEM and STEM) enables for improving the loading efficiency of photosensitizer (ZnO) as the semiconductor is directly coated on the UCN core. Importantly, UCN acts as a transducer to sensitize ZnO and trigger the generation of cytotoxic reactive oxygen species (ROS) to induce cancer cell death. We also present a firefly luciferase (FLuc) reporter gene based molecular biosensor (ARE-FLuc) to measure the antioxidant signaling response activated in cells during the release of ROS in response to the exposure of CSNPs under 980 nm NIR light. The breast cancer cells (MDA-MB-231 and 4T1) exposed to CSNPs showed significant release of ROS as measured by aminophenyl fluorescein (APF) and ARE-FLuc luciferase assays, and ~45% cancer cell death as measured by MTT assay, when illuminated with 980 nm NIR light. PMID:25652742

  15. Background free imaging of upconversion nanoparticle distribution in human skin

    NASA Astrophysics Data System (ADS)

    Song, Zhen; Anissimov, Yuri G.; Zhao, Jiangbo; Nechaev, Andrei V.; Nadort, Annemarie; Jin, Dayong; Prow, Tarl W.; Roberts, Michael S.; Zvyagin, Andrei V.

    2013-06-01

    Widespread applications of nanotechnology materials have raised safety concerns due to their possible penetration through skin and concomitant uptake in the organism. This calls for systematic study of nanoparticle transport kinetics in skin, where high-resolution optical imaging approaches are often preferred. We report on application of emerging luminescence nanomaterial, called upconversion nanoparticles (UCNPs), to optical imaging in skin that results in complete suppression of background due to the excitation light back-scattering and biological tissue autofluorescence. Freshly excised intact and microneedle-treated human skin samples were topically coated with oil formulation of UCNPs and optically imaged. In the first case, 8- and 32-nm UCNPs stayed at the topmost layer of the intact skin, stratum corneum. In the second case, 8-nm nanoparticles were found localized at indentations made by the microneedle spreading in dermis very slowly (estimated diffusion coefficient, Dnp=3-7×10-12 cm2.s-1). The maximum possible UCNP-imaging contrast was attained by suppressing the background level to that of the electronic noise, which was estimated to be superior in comparison with the existing optical labels.

  16. Near-infrared (NIR) up-conversion optogenetics

    PubMed Central

    Hososhima, Shoko; Yuasa, Hideya; Ishizuka, Toru; Hoque, Mohammad Razuanul; Yamashita, Takayuki; Yamanaka, Akihiro; Sugano, Eriko; Tomita, Hiroshi; Yawo, Hiromu

    2015-01-01

    Non-invasive remote control technologies designed to manipulate neural functions have been long-awaited for the comprehensive and quantitative understanding of neuronal network in the brain as well as for the therapy of neurological disorders. Recently, it has become possible for the neuronal activity to be optically manipulated using biological photo-reactive molecules such as channelrhodopsin (ChR)-2. However, ChR2 and its relatives are mostly reactive to visible light, which does not effectively penetrate through biological tissues. In contrast, near-infrared (NIR) light (650–1450 nm) penetrates deep into the tissues because biological systems are almost transparent to light within this so-called ‘imaging window’. Here we used lanthanide nanoparticles (LNPs), composed of rare-earth elements, as luminous bodies to activate ChRs since they absorb low-energy NIR light to emit high-energy visible light (up-conversion). Here, we created a new type of optogenetic system which consists of the donor LNPs and the acceptor ChRs. The NIR laser irradiation emitted visible light from LNPs, then induced the photo-reactive responses in the near-by cells that expressed ChRs. However, there remains room for large improvements in the energy efficiency of the LNP-ChR system. PMID:26552717

  17. Scale-aware saliency for application to frame rate upconversion.

    PubMed

    Jacobson, Natan; Nguyen, Truong Q

    2012-04-01

    Our understanding of human visual perception has been paramount in the development of tools for digital video processing. For this reason, saliency detection, i.e., the determination of visual importance in a scene, has come to the forefront in recent literature. In the proposed work, a new method for scale-aware saliency detection is introduced. Scale determination is afforded through a scale-space model utilizing color and texture cues. Scale information is fed back to a discriminant saliency engine by automatically tuning center-surround parameters through a soft weighting. Excellent results are demonstrated for the proposed method through its performance against a database of measured human fixations. Further evidence of the proposed algorithm's performance is demonstrated through an application to frame rate upconversion. The ability of the algorithm to detect salient objects at multiple scales allows for class-leading performance both objectively, in terms of peak signal-to-noise ratio/structural similarity index, and subjectively. Finally, the need for operator tuning of saliency parameters is dramatically reduced by the inclusion of scale information. The proposed method is well suited for any application requiring automatic saliency determination for images or video. PMID:22167626

  18. Photon upconversion in homogeneous fluorescence-based bioanalytical assays.

    PubMed

    Soukka, Tero; Rantanen, Terhi; Kuningas, Katri

    2008-01-01

    Upconverting phosphors (UCPs) are very attractive reporters for fluorescence resonance energy transfer (FRET)-based bioanalytical assays. The large anti-Stokes shift and capability to convert near-infrared to visible light via sequential absorption of multiple photons enable complete elimination of autofluorescence, which commonly impairs the performance of fluorescence-based assays. UCPs are ideal donors for FRET, because their very narrow-banded emission allows measurement of the sensitized acceptor emission, in principle, without any crosstalk from the donor emission at a wavelength just tens of nanometers from the emission peak of the donor. In addition, acceptor dyes emitting at visible wavelengths are essentially not excited by near-infrared, which further emphasizes the unique potential of upconversion FRET (UC-FRET). These characteristics result in favorable assay performance using detection instrumentation based on epifluorometer configuration and laser diode excitation. Although UC-FRET is a recently emerged technology, it has already been applied in both immunoassays and nucleic acid hybridization assays. The technology is also compatible with optically difficult biological samples, such as whole blood. Significant advances in assay performance are expected using upconverting lanthanide-doped nanocrystals, which are currently under extensive research. UC-FRET, similarly to other fluorescence techniques based on resonance energy transfer, is strongly distance dependent and may have limited applicability, for example in sandwich-type assays for large biomolecules, such as viruses. In this article, we summarize the essentials of UC-FRET, describe its current applications, and outline the expectations for its future potential.

  19. Upconversion nanoparticles for photodynamic therapy and other cancer therapeutics.

    PubMed

    Wang, Chao; Cheng, Liang; Liu, Zhuang

    2013-01-01

    Photodynamic therapy (PDT) is a non-invasive treatment modality for a variety of diseases including cancer. PDT based on upconversion nanoparticles (UCNPs) has received much attention in recent years. Under near-infrared (NIR) light excitation, UCNPs are able to emit high-energy visible light, which can activate surrounding photosensitizer (PS) molecules to produce singlet oxygen and kill cancer cells. Owing to the high tissue penetration ability of NIR light, NIR-excited UCNPs can be used to activate PS molecules in much deeper tissues compared to traditional PDT induced by visible or ultraviolet (UV) light. In addition to the application of UCNPs as an energy donor in PDT, via similar mechanisms, they could also be used for the NIR light-triggered drug release or activation of 'caged' imaging or therapeutic molecules. In this review, we will summarize the latest progresses regarding the applications of UCNPs for photodynamic therapy, NIR triggered drug and gene delivery, as well as several other UCNP-based cancer therapeutic approaches. The future prospects and challenges in this emerging field will be also discussed.

  20. Near-infrared (NIR) up-conversion optogenetics

    NASA Astrophysics Data System (ADS)

    Hososhima, Shoko; Yuasa, Hideya; Ishizuka, Toru; Hoque, Mohammad Razuanul; Yamashita, Takayuki; Yamanaka, Akihiro; Sugano, Eriko; Tomita, Hiroshi; Yawo, Hiromu

    2015-11-01

    Non-invasive remote control technologies designed to manipulate neural functions have been long-awaited for the comprehensive and quantitative understanding of neuronal network in the brain as well as for the therapy of neurological disorders. Recently, it has become possible for the neuronal activity to be optically manipulated using biological photo-reactive molecules such as channelrhodopsin (ChR)-2. However, ChR2 and its relatives are mostly reactive to visible light, which does not effectively penetrate through biological tissues. In contrast, near-infrared (NIR) light (650-1450 nm) penetrates deep into the tissues because biological systems are almost transparent to light within this so-called ‘imaging window’. Here we used lanthanide nanoparticles (LNPs), composed of rare-earth elements, as luminous bodies to activate ChRs since they absorb low-energy NIR light to emit high-energy visible light (up-conversion). Here, we created a new type of optogenetic system which consists of the donor LNPs and the acceptor ChRs. The NIR laser irradiation emitted visible light from LNPs, then induced the photo-reactive responses in the near-by cells that expressed ChRs. However, there remains room for large improvements in the energy efficiency of the LNP-ChR system.

  1. Near-infrared (NIR) up-conversion optogenetics.

    PubMed

    Hososhima, Shoko; Yuasa, Hideya; Ishizuka, Toru; Hoque, Mohammad Razuanul; Yamashita, Takayuki; Yamanaka, Akihiro; Sugano, Eriko; Tomita, Hiroshi; Yawo, Hiromu

    2015-11-10

    Non-invasive remote control technologies designed to manipulate neural functions have been long-awaited for the comprehensive and quantitative understanding of neuronal network in the brain as well as for the therapy of neurological disorders. Recently, it has become possible for the neuronal activity to be optically manipulated using biological photo-reactive molecules such as channelrhodopsin (ChR)-2. However, ChR2 and its relatives are mostly reactive to visible light, which does not effectively penetrate through biological tissues. In contrast, near-infrared (NIR) light (650-1450 nm) penetrates deep into the tissues because biological systems are almost transparent to light within this so-called 'imaging window'. Here we used lanthanide nanoparticles (LNPs), composed of rare-earth elements, as luminous bodies to activate ChRs since they absorb low-energy NIR light to emit high-energy visible light (up-conversion). Here, we created a new type of optogenetic system which consists of the donor LNPs and the acceptor ChRs. The NIR laser irradiation emitted visible light from LNPs, then induced the photo-reactive responses in the near-by cells that expressed ChRs. However, there remains room for large improvements in the energy efficiency of the LNP-ChR system.

  2. Riboflavin photoactivation by upconversion nanoparticles for cancer treatment

    NASA Astrophysics Data System (ADS)

    Khaydukov, E. V.; Mironova, K. E.; Semchishen, V. A.; Generalova, A. N.; Nechaev, A. V.; Khochenkov, D. A.; Stepanova, E. V.; Lebedev, O. I.; Zvyagin, A. V.; Deyev, S. M.; Panchenko, V. Ya.

    2016-10-01

    Riboflavin (Rf) is a vitamin and endogenous photosensitizer capable to generate reactive oxygen species (ROS) under UV-blue irradiation and kill cancer cells, which are characterized by the enhanced uptake of Rf. We confirmed its phototoxicity on human breast adenocarcinoma cells SK-BR-3 preincubated with 30-μM Rf and irradiated with ultraviolet light, and proved that such Rf concentrations (60 μM) are attainable in vivo in tumour site by systemic intravascular injection. In order to extend the Rf photosensitization depth in cancer tissue to 6 mm in depth, we purpose-designed core/shell upconversion nanoparticles (UCNPs, NaYF4:Yb3+:Tm3+/NaYF4) capable to convert 2% of the deeply-penetrating excitation at 975 nm to ultraviolet-blue power. This power was expended to photosensitise Rf and kill SK-BR-3 cells preincubated with UCNPs and Rf, where the UCNP-Rf energy transfer was photon-mediated with ~14% Förster process contribution. SK-BR-3 xenograft regression in mice was observed for 50 days, following the Rf-UCNPs peritumoural injection and near-infrared light photodynamic treatment of the lesions.

  3. Upconversion luminescence tracking of gene delivery via multifunctional nanocapsules.

    PubMed

    Bai, Xilin; Xu, Suying; Liu, Jiali; Wang, Leyu

    2016-04-01

    The real-time fluorescence tracking of gene delivery is very important as it helps to figure out how a vector enters a cell and also to follow its fate within the cell interior. Lanthanide-doped upconversion nanoparticles (UCNPs) have shown great potential in biomedical applications in virtue of their unique optical and biological properties. Herein, we report a simple and versatile strategy to fabricate a multifunctional nanocapsule for effective gene delivery and real-time luminescence tracking. The hydrophobic UCNPs were modified by positively charged amphiphilic polymer together with polyethylene glycol-poly(lactic-co-glycolic acid) (PEG-PLGA) polymer, affording biocompatible nanocapsules with high gene loading capacity and good stability. Red UC luminescence of UCNPs are able to track the delivery of nanocapsules in cells without background fluorescence interference, in the meantime, the green fluorescence of green fluorescence protein (GFP) expressed by the pDNA could subtly monitor the gene transfection efficacy. The results demonstrated that our nanocapsule has ideal biocompatibility, satisfactory gene loading capacity and great bioimaging ability, which is promising for imaging guided cell therapy and gene engineering. PMID:26838389

  4. Polarization-dependent extraordinary optical transmission from upconversion nanoparticles.

    PubMed

    Wang, Peng Hui; Salcedo, Walter J; Pichaandi, Jothirmayanantham; van Veggel, Frank C J M; Brolo, Alexandre G

    2015-11-21

    Enhanced upconversion (UC) emission was experimentally demonstrated using gold double antenna nanoparticles coupled to nanoslits in gold films. The transmitted red emission from UC ytterbium and erbium co-doped sodium yttrium fluoride (NaYF4:Yb(3+)/Er(3+)) nanoparticles (UC NPs) at ∼665 nm (excited with a 980 nm diode laser) was enhanced relative to the green emission at ∼550 nm. The relatively enhanced UC NP emission could be tuned by the different polarization-dependent extraordinary optical transmission modes coupled to the gold nanostructures. Finite-difference time-domain calculations suggest that the preferential enhanced UC emission is related to a combination of different surface plasmon mode excitation coupling to cavity Fabry-Perot interactions. A maximum UC enhancement of 6-fold was measured for nanoslit arrays in the absence of the double antennas. In the presence of the double nanoantennas inside the nanoslits, the UC enhancement was between 2- and 4-fold, depending on the experimental conditions. PMID:26487270

  5. Sensing using rare-earth-doped upconversion nanoparticles.

    PubMed

    Hao, Shuwei; Chen, Guanying; Yang, Chunhui

    2013-01-01

    Optical sensing plays an important role in theranostics due to its capability to detect hint biochemical entities or molecular targets as well as to precisely monitor specific fundamental psychological processes. Rare-earth (RE) doped upconversion nanoparticles (UCNPs) are promising for these endeavors due to their unique frequency converting capability; they emit efficient and sharp visible or ultraviolet (UV) luminescence via use of ladder-like energy levels of RE ions when excited at near infrared (NIR) light that are silent to tissues. These features allow not only a high penetration depth in biological tissues but also a high detection sensitivity. Indeed, the energy transfer between UCNPs and biomolecular or chemical indicators provide opportunities for high-sensitive bio- and chemical-sensing. A temperature-sensitive change of the intensity ratio between two close UC bands promises them for use in temperature mapping of a single living cell. In this work, we review recent investigations on using UCNPs for the detection of biomolecules (avidin, ATP, etc.), ions (cyanide, mecury, etc.), small gas molecules (oxygen, carbon dioxide, ammonia, etc.), as well as for in vitro temperature sensing. We also briefly summarize chemical methods in synthesizing UCNPs of high efficiency that are important for the detection limit. PMID:23650480

  6. Integrated optical modulator for signal up-conversion over radio-on-fiber link.

    PubMed

    Kim, Woo-Kyung; Kwon, Soon-Woo; Jeong, Woo-Jin; Son, Geun-Sik; Lee, Kwang-Hyun; Choi, Woo-Young; Yang, Woo-Seok; Lee, Hyung-Man; Lee, Han-Young

    2009-02-16

    An integrated optical modulator, which consists of a dual-sideband suppressed carrier (DSB-SC) modulator cascaded with a single-sideband (SSB) modulator, is proposed for signal up-conversion over Radio-on-Fiber. Utilizing a single-drive domain inverted structure in both modulators, balanced modulations were obtained without complicated radio frequency (RF) driving circuits and delicate RF phase adjustments. Intermediate frequency (IF) band signal was up-conversed to 60GHz band by using the fabricated device and was transmitted over optical fiber. Experiment results show that the proposed device enables millimeter wave generation and signal transmission without any power penalty caused by chromatic dispersion.

  7. Upconversion-based receivers for quantum hacking-resistant quantum key distribution

    NASA Astrophysics Data System (ADS)

    Jain, Nitin; Kanter, Gregory S.

    2016-07-01

    We propose a novel upconversion (sum frequency generation)-based quantum-optical system design that can be employed as a receiver (Bob) in practical quantum key distribution systems. The pump governing the upconversion process is produced and utilized inside the physical receiver, making its access or control unrealistic for an external adversary (Eve). This pump facilitates several properties which permit Bob to define and control the modes that can participate in the quantum measurement. Furthermore, by manipulating and monitoring the characteristics of the pump pulses, Bob can detect a wide range of quantum hacking attacks launched by Eve.

  8. Endoplasmic Reticulum Glycoprotein Quality Control Regulates CD1d Assembly and CD1d-mediated Antigen Presentation*

    PubMed Central

    Kunte, Amit; Zhang, Wei; Paduraru, Crina; Veerapen, Natacha; Cox, Liam R.; Besra, Gurdyal S.; Cresswell, Peter

    2013-01-01

    The non-classical major histocompatibility complex (MHC) homologue CD1d presents lipid antigens to innate-like lymphocytes called natural-killer T (NKT) cells. These cells, by virtue of their broad cytokine repertoire, shape innate and adaptive immune responses. Here, we have assessed the role of endoplasmic reticulum glycoprotein quality control in CD1d assembly and function, specifically the role of a key component of the quality control machinery, the enzyme UDP glucose glycoprotein glucosyltransferase (UGT1). We observe that in UGT1-deficient cells, CD1d associates prematurely with β2-microglobulin (β2m) and is able to rapidly exit the endoplasmic reticulum. At least some of these CD1d-β2m heterodimers are shorter-lived and can be rescued by provision of a defined exogenous antigen, α-galactosylceramide. Importantly, we show that in UGT1-deficient cells the CD1d-β2m heterodimers have altered antigenicity despite the fact that their cell surface levels are unchanged. We propose that UGT1 serves as a quality control checkpoint during CD1d assembly and further suggest that UGT1-mediated quality control can shape the lipid repertoire of newly synthesized CD1d. The quality control process may play a role in ensuring stability of exported CD1d-β2m complexes, in facilitating presentation of low abundance high affinity antigens, or in preventing deleterious responses to self lipids. PMID:23615906

  9. Interaction of environmental contaminants with zebrafish organic anion transporting polypeptide, Oatp1d1 (Slco1d1)

    SciTech Connect

    Popovic, Marta; Zaja, Roko; Fent, Karl; Smital, Tvrtko

    2014-10-01

    Polyspecific transporters from the organic anion transporting polypeptide (OATP/Oatp) superfamily mediate the uptake of a wide range of compounds. In zebrafish, Oatp1d1 transports conjugated steroid hormones and cortisol. It is predominantly expressed in the liver, brain and testes. In this study we have characterized the transport of xenobiotics by the zebrafish Oatp1d1 transporter. We developed a novel assay for assessing Oatp1d1 interactors using the fluorescent probe Lucifer yellow and transient transfection in HEK293 cells. Our data showed that numerous environmental contaminants interact with zebrafish Oatp1d1. Oatp1d1 mediated the transport of diclofenac with very high affinity, followed by high affinity towards perfluorooctanesulfonic acid (PFOS), nonylphenol, gemfibrozil and 17α-ethinylestradiol; moderate affinity towards carbaryl, diazinon and caffeine; and low affinity towards metolachlor. Importantly, many environmental chemicals acted as strong inhibitors of Oatp1d1. A strong inhibition of Oatp1d1 transport activity was found by perfluorooctanoic acid (PFOA), chlorpyrifos-methyl, estrone (E1) and 17β-estradiol (E2), followed by moderate to low inhibition by diethyl phthalate, bisphenol A, 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4 tetrahydronapthalene and clofibrate. In this study we identified Oatp1d1 as a first Solute Carrier (SLC) transporter involved in the transport of a wide range of xenobiotics in fish. Considering that Oatps in zebrafish have not been characterized before, our work on zebrafish Oatp1d1 offers important new insights on the understanding of uptake processes of environmental contaminants, and contributes to the better characterization of zebrafish as a model species. - Highlights: • We optimized a novel assay for determination of Oatp1d1 interactors • Oatp1d1 is the first SLC characterized fish xenobiotic transporter • PFOS, nonylphenol, diclofenac, EE2, caffeine are high affinity Oatp1d1substrates • PFOA, chlorpyrifos

  10. D1/D5 dopamine receptors modulate spatial memory formation.

    PubMed

    da Silva, Weber C N; Köhler, Cristiano C; Radiske, Andressa; Cammarota, Martín

    2012-02-01

    We investigated the effect of the intra-CA1 administration of the D1/D5 receptor antagonist SCH23390 and the D1/D5 receptor agonist SKF38393 on spatial memory in the water maze. When given immediately, but not 3h after training, SCH23390 hindered long-term spatial memory formation without affecting non-spatial memory or the normal functionality of the hippocampus. On the contrary, post-training infusion of SKF38393 enhanced retention and facilitated the spontaneous recovery of the original spatial preference after reversal learning. Our findings demonstrate that hippocampal D1/D5 receptors play an essential role in spatial memory processing.

  11. A human serotonin 1D receptor variant (5HT1D beta) encoded by an intronless gene on chromosome 6.

    PubMed Central

    Demchyshyn, L; Sunahara, R K; Miller, K; Teitler, M; Hoffman, B J; Kennedy, J L; Seeman, P; Van Tol, H H; Niznik, H B

    1992-01-01

    An intronless gene encoding a serotonin receptor (5HT1D beta) has been cloned and functionally expressed in mammalian fibroblast cultures. Based on the deduced amino acid sequence, the gene encodes a 390-amino acid protein displaying considerable homology, within putative transmembrane domains (approximately 75% identity) to the canine and human 5HT1D receptors. Membranes prepared from CHO cells stably expressing the receptor bound [3H]serotonin with high affinity (Kd 4 nM) and displayed a pharmacological profile consistent, but not identical, with that of the characterized serotonin 5HT1D receptor. Most notably, metergoline and serotonergic piperazine derivatives, as a group, display 3- to 8-fold lower affinity for the 5HT1D beta receptor than for the 5HT1D receptor, whereas both receptors display similar affinities for tryptamine derivatives, including the antimigraine drug sumatriptan. Northern blot analysis revealed an mRNA of approximately 5.5 kilobases expressed in human and monkey frontal cortex, medulla, striatum, hippocampus and amygdala but not in cerebellum, olfactory tubercle, and pituitary. The 5HT1D beta gene maps to human chromosome 6. The existence of multiple neuronal 5HT1D-like receptors may help account for some of the complexities associated with [3H]serotonin binding patterns in native membranes. Images PMID:1351684

  12. 60. BOILER CHAMBER No. 1, D LOOP STEAM GENERATOR AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    60. BOILER CHAMBER No. 1, D LOOP STEAM GENERATOR AND MAIN COOLANT PUMP LOOKING NORTHEAST (LOCATION OOO) - Shippingport Atomic Power Station, On Ohio River, 25 miles Northwest of Pittsburgh, Shippingport, Beaver County, PA

  13. Severe Hypertriglyceridemia in Glut1D on Ketogenic Diet.

    PubMed

    Klepper, Joerg; Leiendecker, Baerbel; Heussinger, Nicole; Lausch, Ekkehart; Bosch, Friedrich

    2016-04-01

    High-fat ketogenic diets are the only treatment available for Glut1 deficiency (Glut1D). Here, we describe an 8-year-old girl with classical Glut1D responsive to a 3:1 ketogenic diet and ethosuximide. After 3 years on the diet a gradual increase of blood lipids was followed by rapid, severe asymptomatic hypertriglyceridemia (1,910 mg/dL). Serum lipid apheresis was required to determine liver, renal, and pancreatic function. A combination of medium chain triglyceride-oil and a reduction of the ketogenic diet to 1:1 ratio normalized triglyceride levels within days but triggered severe myoclonic seizures requiring comedication with sultiam. Severe hypertriglyceridemia in children with Glut1D on ketogenic diets may be underdiagnosed and harmful. In contrast to congenital hypertriglyceridemias, children with Glut1D may be treated effectively by dietary adjustments alone. PMID:26902182

  14. 1D Nanostructures: Controlled Fabrication and Energy Applications

    SciTech Connect

    Hu, Michael Z.

    2013-01-01

    Jian Wei, Xuchun Song, Chunli Yang, and Michael Z. Hu, 1D Nanostructures: Controlled Fabrication and Energy Applications, Journal of Nanomaterials, published special issue (http://www.hindawi.com/journals/jnm/si/197254/) (2013).

  15. Upconversion luminescence in BaMoO{sub 4}:Pr{sup 3+} phosphor for display devices

    SciTech Connect

    Soni, Abhishek Kumar; Rai, Vineet Kumar

    2015-08-28

    The frequency upconversion is an important nonlinear optical property by which near infrared light is converted into the visible light. The BaMoO{sub 4}:Pr{sup 3+} powder phosphor has been synthesized by solid state reaction method. The upconversion emission bands are recorded under the excitation of 808 nm diode laser. The phase formation of the prepared phosphor has been identified by powder X-ray diffraction (XRD) technique. The upconversion emission mechanism and colour coordinate have been explained by using energy level and CIE (International Commission on Illumination) chromaticity diagram study, respectively.

  16. UPCONVERSION LUMINESCENCE ENHANCEMENT OF NaYF4:Yb3+, Er3+ NANOPARTICLES ON INVERSE OPAL SURFACE

    NASA Astrophysics Data System (ADS)

    Liao, Jiayan; Yang, Zhengwen; Wu, Hangjun; Lai, Shenfeng; Qiu, Jianbei; Song, Zhiguo; Yang, Yong; Zhou, Dacheng; Yin, Zhaoyi

    2014-01-01

    LaPO4 inverse opal photonic crystals with different photonic band gaps were fabricated by template-assisted method. The Yb3+/Er3+ co-doped NaYF4 nanoparticles were deposited on the surfaces of the inverse opals, and their up-conversion emission properties were investigated. The upconversion emissions of Yb3+/Er3+ co-doped NaYF4 nanoparticles on the inverse opal surfaces have been enhanced when the upconversion emission bands of the nanoparticles are in the range of photonic band gaps of the inverse opals, which is attributed to an efficient and selective reflection of photonic band gaps.

  17. TBC1D24 genotype–phenotype correlation

    PubMed Central

    Balestrini, Simona; Milh, Mathieu; Castiglioni, Claudia; Lüthy, Kevin; Finelli, Mattea J.; Verstreken, Patrik; Cardon, Aaron; Stražišar, Barbara Gnidovec; Holder, J. Lloyd; Lesca, Gaetan; Mancardi, Maria M.; Poulat, Anne L.; Repetto, Gabriela M.; Banka, Siddharth; Bilo, Leonilda; Birkeland, Laura E.; Bosch, Friedrich; Brockmann, Knut; Cross, J. Helen; Doummar, Diane; Félix, Temis M.; Giuliano, Fabienne; Hori, Mutsuki; Hüning, Irina; Kayserili, Hulia; Kini, Usha; Lees, Melissa M.; Meenakshi, Girish; Mewasingh, Leena; Pagnamenta, Alistair T.; Peluso, Silvio; Mey, Antje; Rice, Gregory M.; Rosenfeld, Jill A.; Taylor, Jenny C.; Troester, Matthew M.; Stanley, Christine M.; Ville, Dorothee; Walkiewicz, Magdalena; Falace, Antonio; Fassio, Anna; Lemke, Johannes R.; Biskup, Saskia; Tardif, Jessica; Ajeawung, Norbert F.; Tolun, Aslihan; Corbett, Mark; Gecz, Jozef; Afawi, Zaid; Howell, Katherine B.; Oliver, Karen L.; Berkovic, Samuel F.; Scheffer, Ingrid E.; de Falco, Fabrizio A.; Oliver, Peter L.; Striano, Pasquale; Zara, Federico

    2016-01-01

    Objective: To evaluate the phenotypic spectrum associated with mutations in TBC1D24. Methods: We acquired new clinical, EEG, and neuroimaging data of 11 previously unreported and 37 published patients. TBC1D24 mutations, identified through various sequencing methods, can be found online (http://lovd.nl/TBC1D24). Results: Forty-eight patients were included (28 men, 20 women, average age 21 years) from 30 independent families. Eighteen patients (38%) had myoclonic epilepsies. The other patients carried diagnoses of focal (25%), multifocal (2%), generalized (4%), and unclassified epilepsy (6%), and early-onset epileptic encephalopathy (25%). Most patients had drug-resistant epilepsy. We detail EEG, neuroimaging, developmental, and cognitive features, treatment responsiveness, and physical examination. In silico evaluation revealed 7 different highly conserved motifs, with the most common pathogenic mutation located in the first. Neuronal outgrowth assays showed that some TBC1D24 mutations, associated with the most severe TBC1D24-associated disorders, are not necessarily the most disruptive to this gene function. Conclusions: TBC1D24-related epilepsy syndromes show marked phenotypic pleiotropy, with multisystem involvement and severity spectrum ranging from isolated deafness (not studied here), benign myoclonic epilepsy restricted to childhood with complete seizure control and normal intellect, to early-onset epileptic encephalopathy with severe developmental delay and early death. There is no distinct correlation with mutation type or location yet, but patterns are emerging. Given the phenotypic breadth observed, TBC1D24 mutation screening is indicated in a wide variety of epilepsies. A TBC1D24 consortium was formed to develop further research on this gene and its associated phenotypes. PMID:27281533

  18. Near-infrared (NIR) optogenetics using up-conversion system

    NASA Astrophysics Data System (ADS)

    Hososhima, Shoko; Yuasa, Hideya; Ishizuka, Toru; Yawo, Hiromu

    2015-03-01

    Non-invasive remote control technologies designed to manipulate neural functions for a comprehensive and quantitative understanding of the neuronal network in the brain as well as for the therapy of neurological disorders have long been awaited. Recently, it has become possible to optically manipulate the neuronal activity using biological photo-reactive molecules such as channelrhodopsin-2 (ChR2). However, ChR2 and its relatives are mostly reactive to visible light which does not effectively penetrate through biological tissues. In contrast, near-infrared (NIR) light penetrates deep into the tissues because biological systems are almost transparent to light within this so-called `imaging window'. Here we used lanthanide nanoparticles (LNPs), which are composed of rare-earth elements, as luminous bodies to activate channelrhodopsins (ChRs) since they absorb low-energy NIR light to emit high-energy visible light (up-conversion). Neuron-glioma-hybrid ND-7/23 cells were cultured with LNP(NaYF4:Sc/Yb/Er) particles (peak emission, 543 nm) and transfected to express C1V1 (peak absorbance, 539 nm), a chimera of ChR1 and VChR1. The photocurrents were generated in response to NIR laser light (976 nm) to a level comparable to that evoked by a filtered Hg lamp (530-550 nm). NIR light pulses also evoked action potentials in the cultured neurons that expressed C1V1. It is suggested that the green luminescent light emitted from LNPs effectively activated C1V1 to generate the photocurrent. With the optimization of LNPs, acceptor photo-reactive biomolecules and optics, this system could be applied to non-invasively actuate neurons deep in the brain.

  19. In Vivo Near-Infrared Photodynamic Therapy Based on Targeted Upconversion Nanoparticles.

    PubMed

    Zhou, Aiguo; Wei, Yanchun; Chen, Qun; Xing, Da

    2015-11-01

    Upconversion nanoparticles have shown to be a promising prospect for biological detection and photodynamic therapy (PDT). The focus of this study was to develop an upconversion nanoparticle modified with a targeting peptide and photosensitizer for near-infrared photodynamic therapy. To produce a tumor-targeting nanophotosensitizer with near-infrared excitation, NaYF4:Yb/Er upconversion nanoparticles were first wrapped with O-carboxymethyl chitosan to develop an upconversion rianoplatform and then chemically conjugated with the photosensitizer pyropheophorbide-a (Ppa) and RGD peptide c(RGDyK). The nanoparticle exhibited low dark toxicity and high biocompatibility. When injected into the tail vein of tumor-bearing U87-MG mice, UCNP-Ppa-RGD revealed an enhanced tumor-specific biodistribution and successful therapeutic effect following near-infrared laser irradiation. It possessed a significantly deeper therapeutic depth compared with conventional visible light triggered PDT using Ppa. The results suggest that the nanoplatform has advantages in the spectral application, and the constructed tumor-specific nanoparticle shows high clinical potential to serve not only as a photodynamic imaging reagent but also as a therapeutic agent for the treatment of large or deeply seated tumors. PMID:26554158

  20. Rare-earth doped colour tuneable up-conversion ZBLAN phosphor for enhancing photocatalysis

    NASA Astrophysics Data System (ADS)

    Méndez-Ramos, J.; Acosta-Mora, P.; Ruiz-Morales, J. C.; Sierra, M.; Redondas, A.; Ruggiero, E.; Salassa, L.; Borges, M. E.; Esparza, P.

    2015-03-01

    Rare-earth doped ZrF4-BaF2-LaF3-AlF3-NaF (ZBLAN) fluoride glasses have been successfully synthesized showing outstanding UV-VIS up-conversion luminescence of Er3+ and Tm3+, sensitized by Yb3+ ions, under near-infrared excitation at 980 nm. The ratio between blue, green and red up-conversion emission bands can be adjusted by varying the pump power density of the incident infrared radiation, resulting in a controlled tuneability of the overall emitting colour from greenish to yellowish. Additionally, the observed high energy UV intense up-conversion emissions are suitable to enhance photocatalytic activity of main water-splitting semiconductor electrodes (such as TiO2) used in sustainable production of hydrogen. Photocatalysis and photolysis degradation of methylene blue in water under sun-like irradiation using benchmark photocatalyst (TiO2 Degussa P25) have been boosted by 20% and by a factor of 2.5 respectively, due to the enhancement of UV radiation that reaches the TiO2 particles by the addition of ZBLAN powder into a slurry-type photo-reactor. Hence, up-conversion ZBLAN phosphors contribute to demonstrate the possibility of transforming the incoming infrared radiation into the UV region needed to bridge the gap of photocatalytic semiconductors.

  1. Multifunctional upconversion nanoprobe for tumor fluorescence imaging and near-infrared thermal therapy

    NASA Astrophysics Data System (ADS)

    Wei, Yanchun; Chen, Qun; Wu, Baoyan; Xing, Da

    2014-09-01

    The combination of diagnostics and therapeutics is growing rapidly in cancer treatment. Here, using upconversion nanoparticles coated with chitosan conjugated with a targeting molecule and loaded with indocyanine green (ICG), an excitation-selectable nanoprobe with highly integrated functionalities, including the emission of visible and near-infrared (NIR) light, strong optical absorption in the NIR region and high photostability was developed. After injected in mice, the nanoprobes targeted to the tumor vascular system. NIR lasers (980 and 808 nm) were then selectively applied to the mice. The results show that, the emitted upconversion fluorescence and NIR fluorescence can be used in a complementary manner for high signal/noise ratio and sensitive tumor imaging for more precise tumor localization; Highly effective photothermal therapy can be realized using 808 nm laser irradiation. The upconversion fluorescence at 654 nm is useful for monitoring treatment effect during thermal therapy. In summary, using the nanoprobes, outstanding therapeutic efficacy could be realized and the nanofabrication strategy would highlight the promise of upconversion nanoparticles in cancer theranostics.

  2. Tuning Crystal Phase and Emission Properties of Upconversion Nanocrystals Through Lanthanide Doping.

    PubMed

    Luo, L; Liu, H B; Yao, L L; Dong, G S; Zhang, W; Wang, Y H; Qiu, Z R; Chen, J

    2016-01-01

    Infrared-to-visible upconversion fluorescent nanocrystals of Yb³⁺/Er³⁺-codoped NaYF₄ and Yb³⁺/Er³⁺/Gd³⁺-tridoped NaYF₄ were synthesized using a modified coprecipitation process. X-ray diffraction and transmission electron diffraction scans of the nanocrystals confirmed that Gd³⁺ doping caused a phase transition to occur in the nanocrystals, changing them from a cubic to a hexagonal phase. Hexagonal phase Yb³⁺/Er³⁺/Gd³⁺-tridoped NaYF₄ nanocrystals displayed much stronger and sharper upconversion luminescence, and larger intensity ratios of red over green emissions relative to their cubic phase counterparts. The influence of the crystal phase on the upconversion emission properties was explored by use of excitation power dependence curves, dynamic fluorescence and Raman spectra. The results suggest that the cubic-to-hexagonal phase transition decreases the crystal field symmetry, and then enhances upconversion luminescence intensity by relaxing forbidden selection rules. The conversion into the hexagonal phase also increases the number of phonon modes, and consequently improves the phonon-assisted energy transfer efficiency from Yb³⁺ to Er³⁺, thus facilitating the output of red emissions. PMID:27398498

  3. An estimate of spherical impactor energy transfer for mechanical frequency up-conversion energy harvester

    NASA Astrophysics Data System (ADS)

    Corr, L. R.; Ma, D. T.

    2016-08-01

    Vibration energy harvesters, which use the impact mechanical frequency up-conversion technique, utilize an impactor, which gains kinetic energy from low frequency ambient environmental vibrations, to excite high frequency systems that efficiently convert mechanical energy to electrical energy. To take full advantage of the impact mechanical frequency up-conversion technique, it is prudent to understand the energy transfer from the low frequency excitations, to the impactor, and finally to the high frequency systems. In this work, the energy transfer from a spherical impactor to a multi degree of freedom spring / mass system, due to Hertzian impact, is investigated to gain insight on how best to design impact mechanical frequency up-conversion energy harvesters. Through this academic work, it is shown that the properties of the contact (or impact) area, i.e., radius of curvature and material properties, only play a minor role in energy transfer and that the equivalent mass of the target system (i.e., the spring / mass system) dictates the total amount of energy transferred during the impact. The novel approach of utilizing the well-known Hertzian impact methodology to gain an understanding of impact mechanical frequency up-conversion energy harvesters has made it clear that the impactor and the high frequency energy generating systems must be designed together as one system to ensure maximum energy transfer, leading to efficient ambient vibration energy harvesters.

  4. The role of Nb in intensity increase of Er ion upconversion luminescence in zirconia

    SciTech Connect

    Smits, K. Sarakovskis, A.; Grigorjeva, L.; Millers, D.; Grabis, J.

    2014-06-07

    It is found that Nb co-doping increases the luminescence and upconversion luminescence intensity in rare earth doped zirconia. Er and Yb-doped nanocrystalline samples with or without Nb co-doping were prepared by sol-gel method and thermally annealed to check for the impact of phase transition on luminescence properties. Phase composition and grain sizes were examined by X-ray diffraction; the morphology was checked by scanning- and high-resolution transmission electron microscopes. Both steady-state and time-resolved luminescence were studied. Comparison of samples with different oxygen vacancy concentrations and different Nb concentrations confirmed the known assumption that oxygen vacancies are the main agents for tetragonal or cubic phase stabilization. The oxygen vacancies quench the upconversion luminescence; however, they also prevent agglomeration of rare-earth ions and/or displacement of rare-earth ions to grain surfaces. It is found that co-doping with Nb ions significantly (>20 times) increases upconversion luminescence intensity. Hence, ZrO{sub 2}:Er:Yb:Nb nanocrystals may show promise for upconversion applications.

  5. Photochemical Upconversion: A Physical or Inorganic Chemistry Experiment for Undergraduates Using a Conventional Fluorimeter

    ERIC Educational Resources Information Center

    Wilke, Bryn M.; Castellano, Felix N.

    2013-01-01

    Photochemical upconversion is a regenerative process that transforms lower-energy photons into higher-energy light through two sequential bimolecular reactions, triplet sensitization of an appropriate acceptor followed by singlet fluorescence producing triplet-triplet annihilation derived from two energized acceptors. This laboratory directly…

  6. Simultaneous excitation and emission enhancements in upconversion luminescence using plasmonic double-resonant gold nanorods

    PubMed Central

    Liu, Xin; Yuan Lei, Dang

    2015-01-01

    The geometry and dimension of a gold nanorod (GNR) are optimally designed to enhance the fluorescence intensity of a lanthanide-doped upconversion nanocrystal placed in close proximity to the GNR. A systematic study of the electromagnetic interaction between the upconversion emitter of three energy levels and the GNR shows that the enhancement effect arising from localized electric field-induced absorption can be balanced by the negative effect of electronic transition from an intermediate state to the ground state of the emitter. The dependence of fluorescence enhancement on the emitter-GNR separation is investigated, and the results demonstrate a maximum enhancement factor of 120 folds and 160 folds at emission wavelengths 650 and 540 nm, respectively. This is achieved at the emitter-GNR separation ranging from 5 to 15 nm, depending on the initial quantum efficiency of the emitter. The modified upconversion luminescence behavior by adjusting the aspect ratio of the GNR and the relative position of the emitter indicates the dominate role of excitation process in the total fluorescence enhancement. These findings are of great importance for rationally designing composite nanostructures of metal nanoparticles and upconversion nanocrystals with maximized plasmonic enhancement for bioimaging and sensing applications. PMID:26468686

  7. Pulsed periodic laser excitation of upconversion luminescence for deep biotissue visualization

    NASA Astrophysics Data System (ADS)

    Pominova, D. V.; Ryabova, A. V.; Linkov, K. G.; Romanishkin, I. D.; Kuznetsov, S. V.; Rozhnova, J. A.; Konov, V. I.; Loschenov, V. B.

    2016-08-01

    Emission spectral properties and quantum efficiency of upconversion particles NaYF4, SrF2, LaF3, BaF2 и CaF2, doped with rare earth ions pair Yb3+–Er3+ were studied using continuous wave (CW) and pulsed periodic excitation modes in the near infrared (NIR) spectral range. Analysis of the obtained results showed that the intensity ratio of upconversion luminescence in green and red spectral ranges depends on excitation pulse duration. Thus, by changing the pulse duration the spectral properties of upconversion luminescence can be controlled. Crystals with higher phonon energy are more sensitive to the change of pumping mode. Interpretation of results was performed on the rate equation model basis. Using numerical methods for all energy levels involved in the upconversion process the population and depopulation dynamics were obtained with respect to the duration of the excitation pulses. It was shown that about 30 ms was required for the complete population of 4F9/2 state, from which the luminescence in the red spectral range occurs. When the pulse duration was less than 30 ms, the 4F9/2 population did not reach a steady state and the intensity of the luminescence in the red part of the spectrum was reduced. The theoretical dependence of the upconversion luminescence intensity in the green and red ranges of the excitation pulse duration for NaYF4:Yb0.2–Er0.02 composition was obtained and demonstrates good agreement with the experimental results.

  8. 1.5-μm optical up-conversion: wafer fusion and related issues

    NASA Astrophysics Data System (ADS)

    Ban, Dayan; Luo, Hui; Liu, Hui-Chun; SpringThorpe, Anthony J.; Wasilewski, Zbigniew R.; Bezinger, Andrew; Bogdanov, Alexei; Buchanan, Margaret

    2004-11-01

    Imaging devices working in the near infrared (NIR), especially in the so-called eye-safe range, i.e., around 1.5 mm, have become increasingly important in many military and commercial applications; these include night vision, covert surveillance, range finding and semiconductor wafer inspection. We proposed a new approach in which a wafer-fused optical up-converter, combined with a commercially available charged coupled device (CCD), functions as an infrared camera. The optical up-converter converts incoming infrared light into shorter wavelength radiation that can be efficiently detected by the silicon CCD (cutoff wavelength about 1 mm). An optical up-converter with high efficiency at room-temperature is critical for low cost and large-area infrared imaging applications. A prototype 1.5 mm optical up-converter based on wafer fusion technology has been successfully fabricated. The device consists of an InGaAs/InP pin photodetector and a GaAs/AlGaAs light emitting diode. Experimental results show that the end-to-end up-conversion efficiency is 0.0177 W/W at room-temperature, corresponding to an internal quantum up-conversion efficiency of 76%. In this paper, the design, fabrications and characterization of the optical up-conversion devices is presented. Issues related to device optimization, such as improving internal and external up-conversion efficiency, are addressed. Preliminary results demonstrate the room-temperature up-conversion imaging operation of a pixelated wafer-fused device.

  9. Multifunctional upconversion mesoporous silica nanostructures for dual modal imaging and in vivo drug delivery.

    PubMed

    Li, Chunxia; Yang, Dongmei; Ma, Ping'an; Chen, Yinyin; Wu, Yuan; Hou, Zhiyou; Dai, Yunlu; Zhao, Jihong; Sui, Changping; Lin, Jun

    2013-12-20

    Incorporating the agents for magnetic resonance imaging (MRI), optical imaging, and therapy in one nanostructured matrix to construct multifunctional nanomedical platform has attracted great attention for simultaneous diagnostic and therapeutic applications. In this work, a facile methodology is developed to construct a multifunctional anticancer drug nanocarrier by combining the special advantages of upconversion nanoparticles and mesoporous silica. β-NaYF4 :Yb(3+) , Er(3+) @β-NaGdF4 :Yb(3+) is chosen as it can provide the dual modality of upconversion luminescence and MRI. Then mesoporous silica is directly coated onto the upconversion nanoparticles to form discrete, monodisperse, highly uniform, and core-shell structured nanospheres (labeled as UCNPs@mSiO2 ), which are subsequently functionalized with hydrophilic polymer poly(ethylene glycol) (PEG) to improve the colloidal stability and biocompatibility. The obtained multifunctional nanocomposites can be used as an anticancer drug delivery carrier and applied for imaging. The anticancer drug doxorubicin (DOX) is absorbed into UCNPs@mSiO2 -PEG nanospheres and released in a pH-sensitive pattern. In vitro cell cytotoxicity tests on cancer cells verify that the DOX-loaded UCNPs@mSiO2 -PEG has comparable cytotoxicity with free DOX at the same concentration of DOX. In addition, the T1 -weighted MRI that measures in aqueous solutions reveals that the contrast brightening increases with the concentration of Gd(3+) component. Upconversion luminescence images of UCNPs@mSiO2 -PEG uptaken by cells show green emission under 980 nm infrared laser excitation. Finally, the nanocomposites show low systematic toxicity and high in vivo antitumor therapy efficacy. These findings highlight the fascinating features of upconversion-mesoporous nanocomposites as multimodality imaging contrast agents and nanocarrier for drug molecules.

  10. Pulsed periodic laser excitation of upconversion luminescence for deep biotissue visualization

    NASA Astrophysics Data System (ADS)

    Pominova, D. V.; Ryabova, A. V.; Linkov, K. G.; Romanishkin, I. D.; Kuznetsov, S. V.; Rozhnova, J. A.; Konov, V. I.; Loschenov, V. B.

    2016-08-01

    Emission spectral properties and quantum efficiency of upconversion particles NaYF4, SrF2, LaF3, BaF2 i CaF2, doped with rare earth ions pair Yb3+-Er3+ were studied using continuous wave (CW) and pulsed periodic excitation modes in the near infrared (NIR) spectral range. Analysis of the obtained results showed that the intensity ratio of upconversion luminescence in green and red spectral ranges depends on excitation pulse duration. Thus, by changing the pulse duration the spectral properties of upconversion luminescence can be controlled. Crystals with higher phonon energy are more sensitive to the change of pumping mode. Interpretation of results was performed on the rate equation model basis. Using numerical methods for all energy levels involved in the upconversion process the population and depopulation dynamics were obtained with respect to the duration of the excitation pulses. It was shown that about 30 ms was required for the complete population of 4F9/2 state, from which the luminescence in the red spectral range occurs. When the pulse duration was less than 30 ms, the 4F9/2 population did not reach a steady state and the intensity of the luminescence in the red part of the spectrum was reduced. The theoretical dependence of the upconversion luminescence intensity in the green and red ranges of the excitation pulse duration for NaYF4:Yb0.2-Er0.02 composition was obtained and demonstrates good agreement with the experimental results.

  11. Size/morphology induced tunable luminescence in upconversion crystals: ultra-strong single-band emission and underlying mechanisms.

    PubMed

    Wang, Zhaofeng; Zeng, Songshan; Yu, Jingfang; Ji, Xiaoming; Zeng, Huidan; Xin, Shuangyu; Wang, Yuhua; Sun, Luyi

    2015-06-01

    In this work, we present a two-step method to controllably synthesize novel and highly efficient upconversion materials, Lu5O4F7:Er(3+),Yb(3+) nano/micro-crystals, and investigate their size/morphology induced tunable upconversion properties. In addition to the common phenomenon aroused by a surface quenching effect, direct experimental evidence for the regulation of phonon modes is obtained in nanoparticles. The findings in this work advance the existing mechanisms for the general explanation of size/morphology induced upconversion features. Because of the adjustment of phonon energy and density as well as the surface quenching effect, the biocompatible Lu5O4F7:Er(3+),Yb(3+) nanoparticles exhibit an ultra-strong single-band red upconversion, rendering them promising for biomedical applications.

  12. Observation of size dependence in multicolor upconversion in single Yb3+, Er3+ Codoped NaYF4 nanocrystals.

    PubMed

    Schietinger, Stefan; Menezes, Leonardo de S; Lauritzen, Björn; Benson, Oliver

    2009-06-01

    In this Letter we report on the investigation of the upconversion emission of single NaYF(4) nanocrystals codoped with Yb(3+) and Er(3+). Single nanocrystals on a coverslip are excited with continuous wave laser light at 973 nm in a confocal setup and the upconversion fluorescence is analyzed with a spectrometer. With the help of an atomic force microscope the size of the nanocrystals is simultaneously determined. A strong size-dependence of the spectral properties of the upconversion signal of individual nanocrystals is observed. We attribute this to a differing number of available phonons in the individual crystals for multiphonon relaxation processes, depending on their size. We believe that this result provides a new strategy in the synthesis of upconversion nanoparticles with different spectral properties by changing only their size as it is well-known from the case of semiconductor quantum dots.

  13. Temperature and impurity concentration effects on upconversion luminescence in LaInO3 doped with Er3+

    NASA Astrophysics Data System (ADS)

    Sarakovskis, A.; Grube, J.; Strals, K.; Krieke, G.; Springis, M.; Mironova-Ulmane, N.; Skvortsova, V.; Yukhno, E. K.; Bashkirov, L. A.

    2016-07-01

    In this paper a novel method for synthesis of LaInO3:Er3+ is reported and upconversion luminescence properties of the synthesized material at different temperatures (9-300 K) are studied. The samples were prepared by co-precipitation and subsequent heat treatment of lanthanum, indium and erbium hydroxides. It is shown that the excitation at 980 nm leads to a strong green upconversion luminescence in the material. At the concentrations above 0.1 mol. % of Er3+ the energy transfer upconversion mechanism of the luminescence becomes evident. Further increase of Er3+ content in the material leads to higher red-to-green upconversion luminescence intensity ratio. The mechanisms responsible for the observed variation are discussed.

  14. Propeller-Like Nanorod-Upconversion Nanoparticle Assemblies with Intense Chiroptical Activity and Luminescence Enhancement in Aqueous Phase.

    PubMed

    Wu, Xiaoling; Xu, Liguang; Ma, Wei; Liu, Liqiang; Kuang, Hua; Kotov, Nicholas A; Xu, Chuanlai

    2016-07-01

    Propeller-like nanoscale assemblies with exceptionally intense chiroptical activity and strong luminescence are prepared using gold nanorods and upconversion nanoparticles. The circular dichroism intensity of the tetramer reached 80.9 mdeg, with g-factor value of 2.1 × 10(-2) . The enhancement factor of upconversion luminescence is as high as 21.3 in aqueous phase. Attomolar bioanalysis of a cancer biomarker with two model is also achieved, showing potential for early disease diagnosis and environmental monitoring.

  15. Energy Migration Engineering of Bright Rare-Earth Upconversion Nanoparticles for Excitation by Light-Emitting Diodes.

    PubMed

    Zhong, Yeteng; Rostami, Iman; Wang, Zihua; Dai, Hongjie; Hu, Zhiyuan

    2015-11-01

    A novel Nd(3+) -sensitized upconversion nanoparticle (UCNP) that can be excited by near-infrared 740 nm light-emitting diode (LED) lamps with bright upconversion luminescence is designed. Yb(3+) ion distribution is engineered to increase the energy migration efficiency. The benefit of the novel LED-excited UCNPs is demonstrated by imaging of breast cancer cells and enabling an economic handheld semiquantitative visual measurement device. PMID:26393770

  16. The GIRAFFE Archive: 1D and 3D Spectra

    NASA Astrophysics Data System (ADS)

    Royer, F.; Jégouzo, I.; Tajahmady, F.; Normand, J.; Chilingarian, I.

    2013-10-01

    The GIRAFFE Archive (http://giraffe-archive.obspm.fr) contains the reduced spectra observed with the intermediate and high resolution multi-fiber spectrograph installed at VLT/UT2 (ESO). In its multi-object configuration and the different integral field unit configurations, GIRAFFE produces 1D spectra and 3D spectra. We present here the status of the archive and the different functionalities to select and download both 1D and 3D data products, as well as the present content. The two collections are available in the VO: the 1D spectra (summed in the case of integral field observations) and the 3D field observations. These latter products can be explored using the VO Paris Euro3D Client (http://voplus.obspm.fr/ chil/Euro3D).

  17. PC-1D installation manual and user's guide

    SciTech Connect

    Basore, P.A.

    1991-05-01

    PC-1D is a software package for personal computers that uses finite-element analysis to solve the fully-coupled two-carrier semiconductor transport equations in one dimension. This program is particularly useful for analyzing the performance of optoelectronic devices such as solar cells, but can be applied to any bipolar device whose carrier flows are primarily one-dimensional. This User's Guide provides the information necessary to install PC-1D, define a problem for solution, solve the problem, and examine the results. Example problems are presented which illustrate these steps. The physical models and numerical methods utilized are presented in detail. This document supports version 3.1 of PC-1D, which incorporates faster numerical algorithms with better convergence properties than previous versions of the program. 51 refs., 17 figs., 5 tabs.

  18. Pitch-based pattern splitting for 1D layout

    NASA Astrophysics Data System (ADS)

    Nakayama, Ryo; Ishii, Hiroyuki; Mikami, Koji; Tsujita, Koichiro; Yaegashi, Hidetami; Oyama, Kenichi; Smayling, Michael C.; Axelrad, Valery

    2015-07-01

    The pattern splitting algorithm for 1D Gridded-Design-Rules layout (1D layout) for sub-10 nm node logic devices is shown. It is performed with integer linear programming (ILP) based on the conflict graph created from a grid map for each designated pitch. The relation between the number of times for patterning and the minimum pitch is shown systematically with a sample pattern of contact layer for each node. From the result, the number of times for patterning for 1D layout is fewer than that for conventional 2D layout. Moreover, an experimental result including SMO and total integrated process with hole repair technique is presented with the sample pattern of contact layer whose pattern density is relatively high among critical layers (fin, gate, local interconnect, contact, and metal).

  19. Flexible Photodetectors Based on 1D Inorganic Nanostructures

    PubMed Central

    Lou, Zheng

    2015-01-01

    Flexible photodetectors with excellent flexibility, high mechanical stability and good detectivity, have attracted great research interest in recent years. 1D inorganic nanostructures provide a number of opportunities and capabilities for use in flexible photodetectors as they have unique geometry, good transparency, outstanding mechanical flexibility, and excellent electronic/optoelectronic properties. This article offers a comprehensive review of several types of flexible photodetectors based on 1D nanostructures from the past ten years, including flexible ultraviolet, visible, and infrared photodetectors. High‐performance organic‐inorganic hybrid photodetectors, as well as devices with 1D nanowire (NW) arrays, are also reviewed. Finally, new concepts of flexible photodetectors including piezophototronic, stretchable and self‐powered photodetectors are examined to showcase the future research in this exciting field. PMID:27774404

  20. Upconversion luminescence of lanthanide-doped mixed CaMoO4-CaWO4 micro-/nano-materials.

    PubMed

    Liu, Jing; Kaczmarek, Anna M; Billet, Jonas; Van Driessche, Isabel; Van Deun, Rik

    2016-08-14

    Uniform mixed CaMoO4-CaWO4 micro-/nano-materials have been successfully synthesised by a facile hydrothermal method. The morphology of these upconversion materials could be changed to different shapes and the size could also be decreased from the micro- to nano-scale by varying the type of surfactant used. It was observed that before heat treatment, the materials show relatively weak green light emission under excitation at 975 nm, whereas after heat treatment, the intensity of the upconversion luminescence increases dramatically while the intensity of the red component decreases relatively. By adjusting the molybdate/tungstate ratio, it was found that the samples with a higher molybdate content have stronger luminescence properties. XRD measurements have been done to investigate the structure of the mixed CaMoO4-CaWO4 upconversion materials. The effect of heat treatment at different temperatures on the emission spectra and XRD patterns has also been studied. TG-DTA was used to further confirm the most suitable temperature for heat treatment. The luminescence lifetimes and CIE coordinates for these samples were also determined. Additionally it was found that Gd(3+) co-doping could further increase the upconversion luminescence from these mixed CaMoO4-CaWO4 materials. Finally, monitoring the upconversion luminescence intensity as a function of laser pump power confirmed the upconversion process to be a two-photon absorption mechanism.

  1. Upconversion luminescence of lanthanide-doped mixed CaMoO4-CaWO4 micro-/nano-materials.

    PubMed

    Liu, Jing; Kaczmarek, Anna M; Billet, Jonas; Van Driessche, Isabel; Van Deun, Rik

    2016-08-14

    Uniform mixed CaMoO4-CaWO4 micro-/nano-materials have been successfully synthesised by a facile hydrothermal method. The morphology of these upconversion materials could be changed to different shapes and the size could also be decreased from the micro- to nano-scale by varying the type of surfactant used. It was observed that before heat treatment, the materials show relatively weak green light emission under excitation at 975 nm, whereas after heat treatment, the intensity of the upconversion luminescence increases dramatically while the intensity of the red component decreases relatively. By adjusting the molybdate/tungstate ratio, it was found that the samples with a higher molybdate content have stronger luminescence properties. XRD measurements have been done to investigate the structure of the mixed CaMoO4-CaWO4 upconversion materials. The effect of heat treatment at different temperatures on the emission spectra and XRD patterns has also been studied. TG-DTA was used to further confirm the most suitable temperature for heat treatment. The luminescence lifetimes and CIE coordinates for these samples were also determined. Additionally it was found that Gd(3+) co-doping could further increase the upconversion luminescence from these mixed CaMoO4-CaWO4 materials. Finally, monitoring the upconversion luminescence intensity as a function of laser pump power confirmed the upconversion process to be a two-photon absorption mechanism. PMID:27396395

  2. GIS-BASED 1-D DIFFUSIVE WAVE OVERLAND FLOW MODEL

    SciTech Connect

    KALYANAPU, ALFRED; MCPHERSON, TIMOTHY N.; BURIAN, STEVEN J.

    2007-01-17

    This paper presents a GIS-based 1-d distributed overland flow model and summarizes an application to simulate a flood event. The model estimates infiltration using the Green-Ampt approach and routes excess rainfall using the 1-d diffusive wave approximation. The model was designed to use readily available topographic, soils, and land use/land cover data and rainfall predictions from a meteorological model. An assessment of model performance was performed for a small catchment and a large watershed, both in urban environments. Simulated runoff hydrographs were compared to observations for a selected set of validation events. Results confirmed the model provides reasonable predictions in a short period of time.

  3. Observation of Dynamical Fermionization in 1D Bose Gases

    NASA Astrophysics Data System (ADS)

    Malvania, Neel; Xia, Lin; Xu, Wei; Wilson, Joshua M.; Zundel, Laura A.; Rigol, Marcos; Weiss, David S.

    2016-05-01

    The momentum distribution of a harmonically trapped 1D Bose gases in the Tonks-Girardeau limit is expected to undergo dynamical fermionization. That is, after the harmonic trap is suddenly turned off, the momentum distribution steadily transforms into that of an ideal Fermi gas in the same initial trap. We measure 1D momentum distributions at variable times after such a quench, and observe the predicted dynamical fermionization. In addition to working in the strong coupling limit, we also perform the experiment with intermediate coupling, where theoretical calculations are more challenging.

  4. A high performance fluorescence switching system triggered electrochemically by Prussian blue with upconversion nanoparticles

    NASA Astrophysics Data System (ADS)

    Zhai, Yiwen; Zhang, Hui; Zhang, Lingling; Dong, Shaojun

    2016-05-01

    A high performance fluorescence switching system triggered electrochemically by Prussian blue with upconversion nanoparticles was proposed. We synthesized a kind of hexagonal monodisperse β-NaYF4:Yb3+,Er3+,Tm3+ upconversion nanoparticle and manipulated the intensity ratio of red emission (at 653 nm) and green emission at (523 and 541 nm) around 2 : 1, in order to match well with the absorption spectrum of Prussian blue. Based on the efficient fluorescence resonance energy transfer and inner-filter effect of the as-synthesized upconversion nanoparticles and Prussian blue, the present fluorescence switching system shows obvious behavior with high fluorescence contrast and good stability. To further extend the application of this system in analysis, sulfite, a kind of important anion in environmental and physiological systems, which could also reduce Prussian blue to Prussian white nanoparticles leading to a decrease of the absorption spectrum, was chosen as the target. And we were able to determine the concentration of sulfite in aqueous solution with a low detection limit and a broad linear relationship.A high performance fluorescence switching system triggered electrochemically by Prussian blue with upconversion nanoparticles was proposed. We synthesized a kind of hexagonal monodisperse β-NaYF4:Yb3+,Er3+,Tm3+ upconversion nanoparticle and manipulated the intensity ratio of red emission (at 653 nm) and green emission at (523 and 541 nm) around 2 : 1, in order to match well with the absorption spectrum of Prussian blue. Based on the efficient fluorescence resonance energy transfer and inner-filter effect of the as-synthesized upconversion nanoparticles and Prussian blue, the present fluorescence switching system shows obvious behavior with high fluorescence contrast and good stability. To further extend the application of this system in analysis, sulfite, a kind of important anion in environmental and physiological systems, which could also reduce Prussian blue to

  5. Non-cooperative Brownian donkeys: A solvable 1D model

    NASA Astrophysics Data System (ADS)

    Jiménez de Cisneros, B.; Reimann, P.; Parrondo, J. M. R.

    2003-12-01

    A paradigmatic 1D model for Brownian motion in a spatially symmetric, periodic system is tackled analytically. Upon application of an external static force F the system's response is an average current which is positive for F < 0 and negative for F > 0 (absolute negative mobility). Under suitable conditions, the system approaches 100% efficiency when working against the external force F.

  6. 1D design style implications for mask making and CEBL

    NASA Astrophysics Data System (ADS)

    Smayling, Michael C.

    2013-09-01

    At advanced nodes, CMOS logic is being designed in a highly regular design style because of the resolution limitations of optical lithography equipment. Logic and memory layouts using 1D Gridded Design Rules (GDR) have been demonstrated to nodes beyond 12nm.[1-4] Smaller nodes will require the same regular layout style but with multiple patterning for critical layers. One of the significant advantages of 1D GDR is the ease of splitting layouts into lines and cuts. A lines and cuts approach has been used to achieve good pattern fidelity and process margin to below 12nm.[4] Line scaling with excellent line-edge roughness (LER) has been demonstrated with self-aligned spacer processing.[5] This change in design style has important implications for mask making: • The complexity of the masks will be greatly reduced from what would be required for 2D designs with very complex OPC or inverse lithography corrections. • The number of masks will initially increase, as for conventional multiple patterning. But in the case of 1D design, there are future options for mask count reduction. • The line masks will remain simple, with little or no OPC, at pitches (1x) above 80nm. This provides an excellent opportunity for continual improvement of line CD and LER. The line pattern will be processed through a self-aligned pitch division sequence to divide pitch by 2 or by 4. • The cut masks can be done with "simple OPC" as demonstrated to beyond 12nm.[6] Multiple simple cut masks may be required at advanced nodes. "Coloring" has been demonstrated to below 12nm for two colors and to 8nm for three colors. • Cut/hole masks will eventually be replaced by e-beam direct write using complementary e-beam lithography (CEBL).[7-11] This transition is gated by the availability of multiple column e-beam systems with throughput adequate for high- volume manufacturing. A brief description of 1D and 2D design styles will be presented, followed by examples of 1D layouts. Mask complexity for 1

  7. Numerical simulations of heavily polluted fine-grained sediment remobilization using 1D, 1D+, and 2D channel schematization.

    PubMed

    Kaiglová, Jana; Langhammer, Jakub; Jiřinec, Petr; Janský, Bohumír; Chalupová, Dagmar

    2015-03-01

    This article used various hydrodynamic and sediment transport models to analyze the potential and the limits of different channel schematizations. The main aim was to select and evaluate the most suitable simulation method for fine-grained sediment remobilization assessment. Three types of channel schematization were selected to study the flow potential for remobilizing fine-grained sediment in artificially modified channels. Schematization with a 1D cross-sectional horizontal plan, a 1D+ approach, splitting the riverbed into different functional zones, and full 2D mesh, adopted in MIKE by the DHI modeling suite, was applied to the study. For the case study, a 55-km stretch of the Bílina River, in the Czech Republic, Central Europe, which has been heavily polluted by the chemical and coal mining industry since the mid-twentieth century, was selected. Long-term exposure to direct emissions of toxic pollutants including heavy metals and persistent organic pollutants (POPs) resulted in deposits of pollutants in fine-grained sediments in the riverbed. Simulations, based on three hydrodynamic model schematizations, proved that for events not exceeding the extent of the riverbed profile, the 1D schematization can provide comparable results to a 2D model. The 1D+ schematization can improve accuracy while keeping the benefits of high-speed simulation and low requirements of input DEM data, but the method's suitability is limited by the channel properties. PMID:25687259

  8. Silane modified upconversion nanoparticles with multifunctions: imaging, therapy and hypoxia detection

    PubMed Central

    Xu, Shihan; Zhang, Xinran; Xu, Hongwei; Dong, Biao; Qu, Xuesong; Chen, Boting; Zhang, Shuang; Zhang, Tianxiang; Cheng, Yu; Xu, Sai; Song, Hongwei

    2016-01-01

    Herein, we report a facile route to synthesize silane coated upconversion nanoparticles (UCNPs@silane) with an ultrathin layer (the thickness: 1–2 nm), which not only provides good biocompatibility, but also affords hydrophobic interspace to load organic molecules to realize multifunctions. Besides the function of upconversion imaging of UCNPs, cancer therapy and oxygen level detection can also be realized by the addition of chemotherapy drug, PTX, and oxygen sensitive molecules, Platinum (II) octaethylporphine (PtOEP). In bio-experiments, besides the MTT assays, therapy efficacy of UCNPs@PTX@silane can also be detected with the confocal laser scanning microscopy (CLSM) by staining methods. UCNPs@PtOEP@silane can afford minimally invasive analysis of dissolved oxygen and then respond sensitively to the variance of intracellular oxygen concentration affected by therapeutic UCNPs@PTX@silane. PMID:26924009

  9. Up-conversion detectors at 1550 nm for quantum communication: review and recent advances

    NASA Astrophysics Data System (ADS)

    Tournier, M.; Alibart, O.; Doutre, F.; Tascu, S.; de Micheli, M. P.; Ostrowsky, D. B.; Thyagarajan, K.; Tanzilli, S.

    Up-conversion, or hybrid, detectors have been investigated in quantum communication experiments to replace Indium-Gallium-Arsenide avalanche photodiodes (InGaAs-APD) for the detection of infrared and telecom single photons. Those detectors are based on the supposedly noise-free process of frequency up-conversion, also called sum-frequency generation (SFG), using a second order (χ^2) non-linear crystal. Powered by an intense pump laser, this process permits transposing with a certain probability the single photons at telecom wavelengths to the visible range where silicon APDs (Si-APD) operate with a much better performance than InGaAs detectors. To date, the literature reports up-conversion detectors having efficiency and noise figures comparable to that of the best commercially available IngaAs-APDs. However, in all of these previous realizations, a pump-induced noise is always observed which was initially expected to be as low as the dark count level of the Si-APDs. Although this additional noise represents a problem for the detection, up-conversion detectors have advantageously replaced InGaAs-APDs in various long-distance quantum cryptography schemes since they offer a continuous regime operation mode instead of a gated mode necessary for InGaAs-APDs, and the possibility of much higher counting rates. Despite attempted explanations, no detailed nor conclusive study of this noise has been reported. The aim of this paper is to offer a definitive explanation for this noise. We first give a review of the state of the art by describing already demonstrated up-conversion detectors. We discuss these realizations especially regarding the choices made for the material, in bulk or guided configurations, the single photon wavelengths, and the pump scheme. Then we describe an original device made of waveguides integrated on periodically poled lithium niobate (PPLN)or on single-domain lithium niobate aimed at investigating the origin of the additional pump-induced noise

  10. Tip enhancement of upconversion photoluminescence from rare earth ion doped nanocrystals.

    PubMed

    Mauser, Nina; Piatkowski, Dawid; Mancabelli, Tobia; Nyk, Marcin; Mackowski, Sebastian; Hartschuh, Achim

    2015-04-28

    We present tip-enhanced upconversion photoluminescence (PL) images of Er(3+)- and Yb(3+)-doped NaYF4 nanocrystals on glass substrates with subdiffraction spatial resolution. Tip-sample distance dependent measurements clearly demonstrate the near-field origin of the image contrast. Time-resolved PL measurements show that the tip increases the spontaneous emission rate of the two emission channels of Er(3+) in the visible region. Very efficient enhancement of upconversion PL is discussed in the context of the two-photon nature of the excitation process and homoenergy transfer between the ions within the nanocrystals. Comparison between different nanocrystals and tips shows a strong influence of the tip shape on the image contrast that becomes particularly relevant for the larger dimensions of the investigated nanocrystals.

  11. Simultaneous quasi-one-dimensional propagation and tuning of upconversion luminescence through waveguide effect.

    PubMed

    Gao, Dangli; Tian, Dongping; Zhang, Xiangyu; Gao, Wei

    2016-02-29

    Luminescence-based waveguide is widely investigated as a promising alternative to conquer the difficulties of efficiently coupling light into a waveguide. But applications have been still limited due to employing blue or ultraviolet light as excitation source with the lower penetration depth leading to a weak guided light. Here, we show a quasi-one-dimensional propagation of luminescence and then resulting in a strong luminescence output from the top end of a single NaYF4:Yb(3+)/Er(3+) microtube under near infrared light excitation. The mechanism of upconversion propagation, based on the optical waveguide effect accompanied with energy migration, is proposed. The efficiency of luminescence output is highly dependent on the concentration of dopant ions, excitation power, morphology, and crystallinity of tube as an indirect evidence of the existence of the optical actived waveguide effect. These findings provide the possibility for the construction of upconversion fiber laser.

  12. Harmonic signal generation and frequency upconversion using selective sideband Brillouin amplification in single-mode fiber.

    PubMed

    Lee, Kwang-Hyun; Choi, Woo-Young

    2007-06-15

    Harmonic signal generation and frequency upconversion at millimeter-wave bands are experimentally demonstrated by using selective sideband Brillouin amplification induced by stimulated Brillouin scattering in a single-mode fiber. The harmonic signals and frequency upconverted signals are simultaneously generated by the beating of optical sidebands, one of which is Brillouin amplified. By using this method, we successfully demonstrate generation of third-harmonic millimeter waves at 32.55 GHz with f(LO) of 10.85 GHz and upconversion of 10 Mbps quadrature-shift keyed data at f(IF) of 1.55 GHz into a 30 GHz band with more than 17 dB RF power gain.

  13. Silane modified upconversion nanoparticles with multifunctions: imaging, therapy and hypoxia detection

    NASA Astrophysics Data System (ADS)

    Xu, Shihan; Zhang, Xinran; Xu, Hongwei; Dong, Biao; Qu, Xuesong; Chen, Boting; Zhang, Shuang; Zhang, Tianxiang; Cheng, Yu; Xu, Sai; Song, Hongwei

    2016-02-01

    Herein, we report a facile route to synthesize silane coated upconversion nanoparticles (UCNPs@silane) with an ultrathin layer (the thickness: 1-2 nm), which not only provides good biocompatibility, but also affords hydrophobic interspace to load organic molecules to realize multifunctions. Besides the function of upconversion imaging of UCNPs, cancer therapy and oxygen level detection can also be realized by the addition of chemotherapy drug, PTX, and oxygen sensitive molecules, Platinum (II) octaethylporphine (PtOEP). In bio-experiments, besides the MTT assays, therapy efficacy of UCNPs@PTX@silane can also be detected with the confocal laser scanning microscopy (CLSM) by staining methods. UCNPs@PtOEP@silane can afford minimally invasive analysis of dissolved oxygen and then respond sensitively to the variance of intracellular oxygen concentration affected by therapeutic UCNPs@PTX@silane.

  14. Simultaneous quasi-one-dimensional propagation and tuning of upconversion luminescence through waveguide effect

    NASA Astrophysics Data System (ADS)

    Gao, Dangli; Tian, Dongping; Zhang, Xiangyu; Gao, Wei

    2016-02-01

    Luminescence-based waveguide is widely investigated as a promising alternative to conquer the difficulties of efficiently coupling light into a waveguide. But applications have been still limited due to employing blue or ultraviolet light as excitation source with the lower penetration depth leading to a weak guided light. Here, we show a quasi-one-dimensional propagation of luminescence and then resulting in a strong luminescence output from the top end of a single NaYF4:Yb3+/Er3+ microtube under near infrared light excitation. The mechanism of upconversion propagation, based on the optical waveguide effect accompanied with energy migration, is proposed. The efficiency of luminescence output is highly dependent on the concentration of dopant ions, excitation power, morphology, and crystallinity of tube as an indirect evidence of the existence of the optical actived waveguide effect. These findings provide the possibility for the construction of upconversion fiber laser.

  15. Polyaniline-coated upconversion nanoparticles with upconverting luminescent and photothermal conversion properties for photothermal cancer therapy

    PubMed Central

    Xing, Yadong; Li, Luoyuan; Ai, Xicheng; Fu, Limin

    2016-01-01

    In this study, we developed a nanosystem based on upconversion nanoparticles (UCNPs) coated with a layer of polyaniline nanoparticles (PANPs). The UCNP induces upconversion luminescence for imaging and photothermal conversion properties are due to PANPs. In vitro experiments showed that the UCNPs-PANPs were nontoxic to cells even at a high concentration (800 µg mL−1). Blood analysis and histological experiments demonstrated that the UCNPs-PANPs exhibited no apparent toxicity in mice in vivo. Besides their efficacy in photothermal cancer cell ablation, the UCNP-PANP nanosystem was found to achieve an effective in vivo tumor ablation effect after irradiation using an 808 nm laser. These results demonstrate the potential of the hybrid nanocomposites for use in imaging-guided photothermal therapy.

  16. Ultrafast mid-infrared spectroscopy by chirped pulse upconversion in 1800-1000cm(-1) region.

    PubMed

    Zhu, Jingyi; Mathes, Tilo; Stahl, Andreas D; Kennis, John T M; Groot, Marie Louise

    2012-05-01

    Broadband femtosecond mid-infrared pulses can be converted into the visible spectral region by chirped pulse upconversion. We report here the upconversion of pump probe transient signals in the frequency region below 1800cm(-1), using the nonlinear optical crystal AgGaGeS4, realizing an important expansion of the application range of this method. Experiments were demonstrated with a slab of GaAs, in which the upconverted signals cover a window of 120cm(-1), with 1.5cm(-1) resolution. In experiments on the BLUF photoreceptor Slr1694, signals below 1 milliOD were well resolved after baseline correction. Possibilities for further optimization of the method are discussed. We conclude that this method is an attractive alternative for the traditional MCT arrays used in most mid-infrared pump probe experiments.

  17. Plasmon-enhanced energy transfer for improved upconversion of infrared radiation in doped-lanthanide nanocrystals.

    PubMed

    Sun, Qi-C; Mundoor, Haridas; Ribot, Josep C; Singh, Vivek; Smalyukh, Ivan I; Nagpal, Prashant

    2014-01-01

    Upconversion of infrared radiation into visible light has been investigated for applications in photovoltaics and biological imaging. However, low conversion efficiency due to small absorption cross-section for infrared light (Yb(3+)), and slow rate of energy transfer (to Er(3+) states) has prevented application of upconversion photoluminescence (UPL) for diffuse sunlight or imaging tissue samples. Here, we utilize resonant surface plasmon polaritons (SPP) waves to enhance UPL in doped-lanthanide nanocrystals. Our analysis indicates that SPP waves not only enhance the electromagnetic field, and hence weak Purcell effect, but also increase the rate of resonant energy transfer from Yb(3+) to Er(3+) ions by 6 fold. While we do observe strong metal mediated quenching (14-fold) of green fluorescence on flat metal surfaces, the nanostructured metal is resonant in the infrared and hence enhances the nanocrystal UPL. This strong Coulombic effect on energy transfer can have important implications for other fluorescent and excitonic systems too.

  18. Multifunctional Nd3+-sensitized upconversion nanomaterials for synchronous tumor diagnosis and treatment

    NASA Astrophysics Data System (ADS)

    Chen, Yinyin; Liu, Bei; Deng, Xiaoran; Huang, Shanshan; Hou, Zhiyao; Li, Chunxia; Lin, Jun

    2015-04-01

    Core-shell structured Nd3+-sensitized NaYF4:Yb/Nd/Er@NaYF4:Nd@mSiO2 nanoparticles (NPs) were designed and synthesized. The NaYF4:Yb/Nd/Er@NaYF4:Nd core imparts the nanomaterials with luminescence properties for upconversion optical imaging under 808 nm laser irradiation, whereas the mesoporous SiO2 shell allows the nanomaterials to be loaded with anticancer drug doxorubicin (DOX). In vivo toxicity assessment has confirmed that the NPs have low systematic toxicity in healthy mice. In vivo antitumor activity shows that the nanocomposites exhibit greater antitumor efficacy than pure DOX. As a result, the composite nanomaterials can serve as nanotheranostic materials for synchronous upconversion luminescence imaging under 808 nm laser irradiation, and as anticancer drug delivery vehicles, so as to integrate the diagnosis and treatment of cancers in vivo.

  19. Morphologically controlled synthesis of colloidal upconversion nanophosphors and their shape-directed self-assembly

    PubMed Central

    Ye, Xingchen; Collins, Joshua E.; Kang, Yijin; Chen, Jun; Chen, Daniel T. N.; Yodh, Arjun G.; Murray, Christopher B.

    2010-01-01

    We report a one-pot chemical approach for the synthesis of highly monodisperse colloidal nanophosphors displaying bright upconversion luminescence under 980 nm excitation. This general method optimizes the synthesis with initial heating rates up to 100 °C/minute generating a rich family of nanoscale building blocks with distinct morphologies (spheres, rods, hexagonal prisms, and plates) and upconversion emission tunable through the choice of rare earth dopants. Furthermore, we employ an interfacial assembly strategy to organize these nanocrystals (NCs) into superlattices over multiple length scales facilitating the NC characterization and enabling systematic studies of shape-directed assembly. The global and local ordering of these superstructures is programmed by the precise engineering of individual NC’s size and shape. This dramatically improved nanophosphor synthesis together with insights from shape-directed assembly will advance the investigation of an array of emerging biological and energy-related nanophosphor applications. PMID:21148771

  20. Polyaniline-coated upconversion nanoparticles with upconverting luminescent and photothermal conversion properties for photothermal cancer therapy.

    PubMed

    Xing, Yadong; Li, Luoyuan; Ai, Xicheng; Fu, Limin

    2016-01-01

    In this study, we developed a nanosystem based on upconversion nanoparticles (UCNPs) coated with a layer of polyaniline nanoparticles (PANPs). The UCNP induces upconversion luminescence for imaging and photothermal conversion properties are due to PANPs. In vitro experiments showed that the UCNPs-PANPs were nontoxic to cells even at a high concentration (800 µg mL(-1)). Blood analysis and histological experiments demonstrated that the UCNPs-PANPs exhibited no apparent toxicity in mice in vivo. Besides their efficacy in photothermal cancer cell ablation, the UCNP-PANP nanosystem was found to achieve an effective in vivo tumor ablation effect after irradiation using an 808 nm laser. These results demonstrate the potential of the hybrid nanocomposites for use in imaging-guided photothermal therapy. PMID:27621625

  1. Synthesis of NaYF4:Yb3+, Er3+ upconversion nanoparticles in normal microemulsions.

    PubMed

    Shan, Shu-Nan; Wang, Xiu-Ying; Jia, Neng-Qin

    2011-01-01

    An interface-controlled reaction in normal microemulsions (water/ethanol/sodium oleate/oleic acid/n-hexane) was designed to prepare NaYF4:Yb3+, Er3+ upconversion nanoparticles. The phase diagram of the system was first studied to obtain the appropriate oil-in-water microemulsions. Transmission electron microscopy and X-ray powder diffractometer measurements revealed that the as-prepared nanoparticles were spherical, monodisperse with a uniform size of 20 nm, and of cubic phase with good crystallinity. Furthermore, these nanoparticles have good dispersibility in nonpolar organic solvents and exhibit visible upconversion luminescence of orange color under continuous excitation at 980 nm. Then, a thermal treatment for the products was found to enhance the luminescence intensity. In addition, because of its inherent merit in high yielding and being economical, this synthetic method could be utilized for preparation of the UCNPs on a large scale. PMID:21968102

  2. A facile one-pot method to synthesize ultrasmall core-shell superparamagnetic and upconversion nanoparticles.

    PubMed

    Cheng, Qian; Guo, Hongxuan; Li, Yu; Liu, Shouxin; Sui, Jiehe; Cai, Wei

    2016-08-01

    Ultrasmall core-shell Fe3O4@NaYF4:Yb(3+)/Er(3+) nanoparticles with bifunctional properties have been successfully synthesized via one pot thermolysis method using oleylamine as both solvent and stabilizer. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), upconversion (UC) luminescence spectra and the physical properties measurement system (PPMS) were used to characterize the resulting samples. The synthesized samples have uniform morphology with a mean size of 14.5nm and excellent dispersibility. Moreover, these nanoparticles exhibit superparamagnetic behaviour with saturation magnetization of 8.45emμ/g and efficient up-conversion emission with a two-photon induced process when excited by a 980nm laser. These results suggest that the synthesized ultrasmall bifunctional nanoparticles may find many biomedical applications, such as clinical diagnosis and treatment of cancers.

  3. Simultaneous quasi-one-dimensional propagation and tuning of upconversion luminescence through waveguide effect

    PubMed Central

    Gao, Dangli; Tian, Dongping; Zhang, Xiangyu; Gao, Wei

    2016-01-01

    Luminescence-based waveguide is widely investigated as a promising alternative to conquer the difficulties of efficiently coupling light into a waveguide. But applications have been still limited due to employing blue or ultraviolet light as excitation source with the lower penetration depth leading to a weak guided light. Here, we show a quasi-one-dimensional propagation of luminescence and then resulting in a strong luminescence output from the top end of a single NaYF4:Yb3+/Er3+ microtube under near infrared light excitation. The mechanism of upconversion propagation, based on the optical waveguide effect accompanied with energy migration, is proposed. The efficiency of luminescence output is highly dependent on the concentration of dopant ions, excitation power, morphology, and crystallinity of tube as an indirect evidence of the existence of the optical actived waveguide effect. These findings provide the possibility for the construction of upconversion fiber laser. PMID:26926491

  4. Up-conversion dynamics for temporally entangled two-photon pulses

    SciTech Connect

    Nakatani, Masatoshi; Shimizu, Ryosuke; Koshino, Kazuki

    2011-01-15

    We analyze the up conversion of a two-photon pulse having temporal entanglement on the basis of a full quantum formalism that treats both photons and optical media quantum mechanically. We derive a formula of the up-converted photon wave function, which is applicable to arbitrary input two-photon states for a three-level system, as the simplest second-order nonlinear optical system. As the input, we employ three kinds of temporally entangled two-photon pulses: correlated, uncorrelated, and anticorrelated. We observe the up-conversion efficiency and the temporal profile of the up-converted photon. Our results reveal the crossover behavior of the up conversion from anticorrelation to correlation and show how the temporal correlation in the input is reflected in the up-conversion process.

  5. Recent advances in lanthanide-doped upconversion nanomaterials: synthesis, nanostructures and surface modification

    NASA Astrophysics Data System (ADS)

    Qiu, Peiyu; Zhou, Na; Chen, Hengyu; Zhang, Chunlei; Gao, Guo; Cui, Daxiang

    2013-11-01

    Owing to their unique photo-physical properties, rare-earth ions-doped upconversion nanoparticles (UCNPs) have attracted extensive attention in recent years. UCNPs have many special merits, such as a long luminescence lifetime, narrow emission band widths, high quantum yields and low toxicity, which allows their potential applications in bio-medical field, biological luminescent labels and drug delivery carriers. Compared with traditional fluorescence labels exited by UV (ultraviolet), such as organic dyes and quantum dots, UCNPs can transfer near-infrared (NIR) light into visible light, which is commonly called upconversion luminescence (UCL). This paper reviews the recent advances of several typical synthesis methods of UCNPs in detail as well as the fabrication and optimization of the particle morphology, and the latest advances of UCNPs for multimode imaging, surface passivation and functionalization are also described.

  6. Temporal full-colour tuning through non-steady-state upconversion

    NASA Astrophysics Data System (ADS)

    Deng, Renren; Qin, Fei; Chen, Runfeng; Huang, Wei; Hong, Minghui; Liu, Xiaogang

    2015-03-01

    Developing light-harvesting materials with tunable emission colours has always been at the forefront of colour display technologies. The variation in materials composition, phase and structure can provide a useful tool for producing a wide range of emission colours, but controlling the colour gamut in a material with a fixed composition remains a daunting challenge. Here, we demonstrate a convenient, versatile approach to dynamically fine-tuning emission in the full colour range from a new class of core-shell upconversion nanocrystals by adjusting the pulse width of infrared laser beams. Our mechanistic investigations suggest that the unprecedented colour tunability from these nanocrystals is governed by a non-steady-state upconversion process. These findings provide keen insights into controlling energy transfer in out-of-equilibrium optical processes, while offering the possibility for the construction of true three-dimensional, full-colour display systems with high spatial resolution and locally addressable colour gamut.

  7. Enhanced up-conversion of entangled photons and quantum interference under a localized field in nanostructures.

    PubMed

    Osaka, Yoshiki; Yokoshi, Nobuhiko; Nakatani, Masatoshi; Ishihara, Hajime

    2014-04-01

    We theoretically investigate the up-conversion process of two entangled photons on a molecule, which is coupled by a cavity or nanoscale metallic structure. Within one-dimensional input-output theory, the propagators of the photons are derived analytically and the up-conversion probability is calculated numerically. It is shown that the coupling with the nanostructure clearly enhances the process. We also find that the enhancement becomes further pronounced for some balanced system parameters, such as the quantum correlation between photons, radiation decay, and coupling between the nanostructure and molecule. The nonmonotonic dependencies are reasonably explained in view of quantum interference between the coupled modes of the whole system. This result indicates that controlling quantum interference and correlation is crucial for few-photon nonlinearity, and provides a new guidance to wide variety of fields, e.g., quantum electronics and photochemistry.

  8. Silane modified upconversion nanoparticles with multifunctions: imaging, therapy and hypoxia detection.

    PubMed

    Xu, Shihan; Zhang, Xinran; Xu, Hongwei; Dong, Biao; Qu, Xuesong; Chen, Boting; Zhang, Shuang; Zhang, Tianxiang; Cheng, Yu; Xu, Sai; Song, Hongwei

    2016-01-01

    Herein, we report a facile route to synthesize silane coated upconversion nanoparticles (UCNPs@silane) with an ultrathin layer (the thickness: 1-2 nm), which not only provides good biocompatibility, but also affords hydrophobic interspace to load organic molecules to realize multifunctions. Besides the function of upconversion imaging of UCNPs, cancer therapy and oxygen level detection can also be realized by the addition of chemotherapy drug, PTX, and oxygen sensitive molecules, Platinum (II) octaethylporphine (PtOEP). In bio-experiments, besides the MTT assays, therapy efficacy of UCNPs@PTX@silane can also be detected with the confocal laser scanning microscopy (CLSM) by staining methods. UCNPs@PtOEP@silane can afford minimally invasive analysis of dissolved oxygen and then respond sensitively to the variance of intracellular oxygen concentration affected by therapeutic UCNPs@PTX@silane.

  9. Polyaniline-coated upconversion nanoparticles with upconverting luminescent and photothermal conversion properties for photothermal cancer therapy

    PubMed Central

    Xing, Yadong; Li, Luoyuan; Ai, Xicheng; Fu, Limin

    2016-01-01

    In this study, we developed a nanosystem based on upconversion nanoparticles (UCNPs) coated with a layer of polyaniline nanoparticles (PANPs). The UCNP induces upconversion luminescence for imaging and photothermal conversion properties are due to PANPs. In vitro experiments showed that the UCNPs-PANPs were nontoxic to cells even at a high concentration (800 µg mL−1). Blood analysis and histological experiments demonstrated that the UCNPs-PANPs exhibited no apparent toxicity in mice in vivo. Besides their efficacy in photothermal cancer cell ablation, the UCNP-PANP nanosystem was found to achieve an effective in vivo tumor ablation effect after irradiation using an 808 nm laser. These results demonstrate the potential of the hybrid nanocomposites for use in imaging-guided photothermal therapy. PMID:27621625

  10. Synthesis of NaYF4:Yb3+, Er3+ upconversion nanoparticles in normal microemulsions

    NASA Astrophysics Data System (ADS)

    Shan, Shu-Nan; Wang, Xiu-Ying; Jia, Neng-Qin

    2011-10-01

    An interface-controlled reaction in normal microemulsions (water/ethanol/sodium oleate/oleic acid/ n-hexane) was designed to prepare NaYF4:Yb3+, Er3+ upconversion nanoparticles. The phase diagram of the system was first studied to obtain the appropriate oil-in-water microemulsions. Transmission electron microscopy and X-ray powder diffractometer measurements revealed that the as-prepared nanoparticles were spherical, monodisperse with a uniform size of 20 nm, and of cubic phase with good crystallinity. Furthermore, these nanoparticles have good dispersibility in nonpolar organic solvents and exhibit visible upconversion luminescence of orange color under continuous excitation at 980 nm. Then, a thermal treatment for the products was found to enhance the luminescence intensity. In addition, because of its inherent merit in high yielding and being economical, this synthetic method could be utilized for preparation of the UCNPs on a large scale.

  11. Upconversion emission properties of CeO2: Tm3+, Yb3+ inverse opal photonic crystals

    NASA Astrophysics Data System (ADS)

    Cheng, Gong; Wu, Hangjun; Yang, Zhengwen; Liao, Jiayan; Lai, Shenfeng; Qiu, Jianbei; Song, Zhiguo

    2014-10-01

    The ordered and disordered templates were assembled by vertical deposition of polystyrene microspheres. The CeO2: Tm3+, Yb3+ precursor solution was used to infiltrate into the voids of the ordered and disordered templates, respectively. Then the ordered and disordered templates were calcined at 950°C in an air furnace, and the CeO2: Tm3+, Yb3+ inverse opals were obtained. The upconversion emissions from CeO2: Tm3+, Yb3+ inverse opals were suppressed due to the photon trapping caused by Bragg reflection of lattice planes when the upconversion emission band was in the range of the photonic band gaps in the inverse opals.

  12. Ultraviolet upconversion luminescence of Gd{sup 3+} and Eu{sup 3+} in nano-structured glass ceramics

    SciTech Connect

    Lin, Hang; Chen, Daqin; Yu, Yunlong; Yang, Anping; Zhang, Rui; Wang, Yuansheng

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer Ultraviolet upconversion emissions of Eu{sup 3+} and Gd{sup 3+} are rarely studied. Black-Right-Pointing-Pointer Nanostructured glass ceramic is developed as a host for ultraviolet upconversion. Black-Right-Pointing-Pointer Ultraviolet upconversion signal are found greatly enhanced after crystallization. Black-Right-Pointing-Pointer It is promising for fabricating novel ultraviolet upconversion lasers. -- Abstract: Ultraviolet multiphoton upconversion emissions of Eu{sup 3+} ({sup 5}H{sub 3-7}, {sup 5}G{sub 2-6}, {sup 5}L{sub 6} {yields} {sup 7}F{sub 0}) and Gd{sup 3+} ({sup 6}I{sub J}, {sup 6}P{sub J} {yields} {sup 8}S{sub 7/2}) are studied in the Eu{sup 3+} (or Gd{sup 3+}) doped SiO{sub 2}-Al{sub 2}O{sub 3}-NaF-YF{sub 3} precursor glasses and glass ceramics containing {beta}-YF{sub 3} nanocrystals, under continuous-wavelength 976 nm laser pumping. It is experimentally demonstrated that energy transfer from Yb{sup 3+} to Tm{sup 3+}, then further to Eu{sup 3+} or Gd{sup 3+} is responsible for the upconversion process. Compared to those in the precursor glasses, the upconversion emission intensities in the glass ceramics are greatly enhanced, owing to the participation of rare earth ions into the low-phonon-energy environment of {beta}-YF{sub 3} nanocrystals. Hopefully, the studied glass ceramics may find potential applications in the field of ultraviolet solid-state lasers.

  13. IRRS, UV-Vis-NIR absorption and photoluminescence upconversion in Ho 3+-doped oxyfluorophosphate glasses

    NASA Astrophysics Data System (ADS)

    Karmakar, Basudeb

    2005-09-01

    Infrared reflection spectroscopic (IRRS), ultraviolet-visible-near infrared (UV-Vis-NIR) absorption and photoluminescence upconversion properties with special emphasis on the spectrochemistry of the oxyfluorophosphate (oxide incorporated fluorophosphates) glasses of the Ba(PO 3) 2-AlF 3-CaF 2-SrF 2-MgF 2-Ho 2O 3 system have been studied with different concentrations (0.1, 0.3 and 1.0 mol%) of Ho 2O 3. IRRS spectral band position and intensity of Ho 3+ ion doped oxyfluorophosphate glasses have been discussed in terms of reduced mass and force constant. UV-Vis-NIR absorption band position has been justified with quantitative calculation of nephelauxetic parameter and covalent bonding characteristics of the host. NIR to visible upconversion has been investigated by exciting at 892 nm at room temperature. Three upconverted bands originated from the 5F 3→ 5I 8, ( 5S 2, 5F 4)→ 5I 8 and 5F 5→ 5I 8 transitions have found to be centered at 491 nm (blue, medium), 543 nm (green, very strong) and 658 nm (red, weak), respectively. These bands have been justified from the evaluation of the absorption, normal (down conversion) fluorescence and excitation spectra. The upconversion processes have been explained by the excited state absorption (ESA), energy transfer (ET) and cross relaxation (CR) mechanisms involving population of the metastable (storage) energy levels by multiphonon deexcitation effect. It is evident from the IRRS study that the upconversion phenomena are expedited by the low multiphonon relaxation rate in oxyfluorophosphate glasses owing to their high intense low phonon energy (˜600 cm -1) which is very close to that of fluoride glasses (500-600 cm -1).

  14. Upconversion ratiometric fluorescence and colorimetric dual-readout assay for uric acid.

    PubMed

    Fang, Aijin; Wu, Qiongqiong; Lu, Qiujun; Chen, Hongyu; Li, Haitao; Liu, Meiling; Zhang, Youyu; Yao, Shouzhuo

    2016-12-15

    A new upconversion colorimetric and ratiometric fluorescence detection method for uric acid (UA) has been designed. Yb(3+), Er(3+) and Tm(3+) co-doped NaYF4 nanoparticles (UCNPs) was synthesized. The co-doped NaYF4 nanoparticles, emit upconversion fluorescence with four typical emission peaks centered at 490nm, 557nm, 670nm and 705nm under the 980nm near-infrared (NIR) irradiation. The ZnFe2O4 magnetic nanoparticles (MNPs) possessing excellent peroxidase-like activity was prepared and used to catalyze oxidation the coupling of N-ethyl-N-(3-sulfopropyl)-3-methylaniline sodium salt (TOPS) and 4-amino-antipyrine (4-AAP) in the presence of H2O2 to form purple products (compound 1) which has a characteristic absorption peak located at 550nm. The upconversion fluorescence at 557nm was quenched by the compound 1 while the upconversion emission at 705nm was essentially unchanged, the fluorescence ratio ((I557/I705)0/(I557/I705)) is positively proportional to UA concentration in existence of uricase. More importantly, colorimetric signal can be easily observed and applied to directly distinguish the concentration of UA by the naked eye. Under the optimized conditions, the linear range of colorimetric and ratiometric fluorescence sensing towards UA was 0.01-1mM, the detection limits were as low as 5.79μM and 2.86μM (S/N=3), respectively. The proposed method has been successfully applied to the analysis of UA in human serum. These results indicate that the colorimetric and ratiometric fluorescence dual-readout assay method has great potential for applications in physiological and pathological diagnosis. PMID:27471157

  15. 1-D Numerical Analysis of ABCC Engine Performance

    NASA Technical Reports Server (NTRS)

    Holden, Richard

    1999-01-01

    ABCC engine combines air breathing and rocket engine into a single engine to increase the specific impulse over an entire flight trajectory. Except for the heat source, the basic operation of the ABCC is similar to the basic operation of the RBCC engine. The ABCC is intended to have a higher specific impulse than the RBCC for single stage Earth to orbit vehicle. Computational fluid dynamics (CFD) is a useful tool for the analysis of complex transport processes in various components in ABCC propulsion system. The objective of the present research was to develop a transient 1-D numerical model using conservation of mass, linear momentum, and energy equations that could be used to predict flow behavior throughout a generic ABCC engine following a flight path. At specific points during the development of the 1-D numerical model a myriad of tests were performed to prove the program produced consistent, realistic numbers that follow compressible flow theory for various inlet conditions.

  16. Phase diagram of a bulk 1d lattice Coulomb gas

    NASA Astrophysics Data System (ADS)

    Démery, V.; Monsarrat, R.; Dean, D. S.; Podgornik, R.

    2016-01-01

    The exact solution, via transfer matrix, of the simple one-dimensional lattice Coulomb gas (1d LCG) model can reproduce peculiar features of ionic liquid capacitors, such as overscreening, layering, and camel- and bell-shaped capacitance curves. Using the same transfer matrix method, we now compute the bulk properties of the 1d LCG in the constant voltage ensemble. We unveil a phase diagram with rich structure exhibiting low-density disordered and high-density ordered phases, separated by a first-order phase transition at low temperature; the solid state at full packing can be ordered or not, depending on the temperature. This phase diagram, which is strikingly similar to its three-dimensional counterpart, also sheds light on the behaviour of the confined system.

  17. 1D Josephson quantum interference grids: diffraction patterns and dynamics

    NASA Astrophysics Data System (ADS)

    Lucci, M.; Badoni, D.; Corato, V.; Merlo, V.; Ottaviani, I.; Salina, G.; Cirillo, M.; Ustinov, A. V.; Winkler, D.

    2016-02-01

    We investigate the magnetic response of transmission lines with embedded Josephson junctions and thus generating a 1D underdamped array. The measured multi-junction interference patterns are compared with the theoretical predictions for Josephson supercurrent modulations when an external magnetic field couples both to the inter-junction loops and to the junctions themselves. The results provide a striking example of the analogy between Josephson phase modulation and 1D optical diffraction grid. The Fiske resonances in the current-voltage characteristics with voltage spacing {Φ0}≤ft(\\frac{{\\bar{c}}}{2L}\\right) , where L is the total physical length of the array, {Φ0} the magnetic flux quantum and \\bar{c} the speed of light in the transmission line, demonstrate that the discrete line supports stable dynamic patterns generated by the ac Josephson effect interacting with the cavity modes of the line.

  18. Morphodynamics and sediment tracers in 1-D (MAST-1D): 1-D sediment transport that includes exchange with an off-channel sediment reservoir

    NASA Astrophysics Data System (ADS)

    Lauer, J. Wesley; Viparelli, Enrica; Piégay, Hervé

    2016-07-01

    Bed material transported in geomorphically active gravel bed rivers often has a local source at nearby eroding banks and ends up sequestered in bars not far downstream. However, most 1-D numerical models for gravel transport assume that gravel originates from and deposits on the channel bed. In this paper, we present a 1-D framework for simulating morphodynamic evolution of bed elevation and size distribution in a gravel-bed river that actively exchanges sediment with its floodplain, which is represented as an off-channel sediment reservoir. The model is based on the idea that sediment enters the channel at eroding banks whose elevation depends on total floodplain sediment storage and on the average elevation of the floodplain relative to the channel bed. Lateral erosion of these banks occurs at a specified rate that can represent either net channel migration or channel widening. Transfer of material out of the channel depends on a typical bar thickness and a specified lateral exchange rate due either to net channel migration or narrowing. The model is implemented using an object oriented framework that allows users to explore relationships between bank supply, bed structure, and lateral change rates. It is applied to a ∼50-km reach of the Ain River, France, that experienced significant reduction in sediment supply due to dam construction during the 20th century. Results are strongly sensitive to lateral exchange rates, showing that in this reach, the supply of sand and gravel at eroding banks and the sequestration of gravel in point bars can have strong influence on overall reach-scale sediment budgets.

  19. Monitoring Delamination of Thermal Barrier Coatings by Near-Infrared and Upconversion Luminescence Imaging

    NASA Technical Reports Server (NTRS)

    Eldridge, J. I.; Martin, R. E.; Singh, Jogender; Wolfe, Doug E.

    2008-01-01

    Previous work has demonstrated that TBC delamination can be monitored by incorporating a thin luminescent sublayer that produces greatly increased luminescence intensity from delaminated regions of the TBC. Initial efforts utilized visible-wavelength luminescence from either europium or erbium doped sublayers. This approach exhibited good sensitivity to delamination of electron-beam physical-vapor-deposited (EB-PVD) TBCs, but limited sensitivity to delamination of the more highly scattering plasma-sprayed TBCs due to stronger optical scattering and to interference by luminescence from rare-earth impurities. These difficulties have now been overcome by new strategies employing near-infrared (NIR) and upconversion luminescence imaging. NIR luminescence at 1550 nm was produced in an erbium plus ytterbium co-doped yttria-stabilized zirconia (YSZ) luminescent sublayer using 980-nm excitation. Compared to visible-wavelength luminescence, these NIR emission and excitation wavelengths are much more weakly scattered by the TBC and therefore show much improved depth-probing capabilities. In addition, two-photon upconversion luminescence excitation at 980 nm wavelength produces luminescence emission at 562 nm with near-zero fluorescence background and exceptional contrast for delamination indication. The ability to detect TBC delamination produced by Rockwell indentation and by furnace cycling is demonstrated for both EB-PVD and plasma-sprayed TBCs. The relative strengths of the NIR and upconversion luminescence methods for monitoring TBC delamination are discussed.

  20. The Intersection of CMOS Microsystems and Upconversion Nanoparticles for Luminescence Bioimaging and Bioassays

    PubMed Central

    Wei, Liping.; Doughan, Samer.; Han, Yi.; DaCosta, Matthew V.; Krull, Ulrich J.; Ho, Derek.

    2014-01-01

    Organic fluorophores and quantum dots are ubiquitous as contrast agents for bio-imaging and as labels in bioassays to enable the detection of biological targets and processes. Upconversion nanoparticles (UCNPs) offer a different set of opportunities as labels in bioassays and for bioimaging. UCNPs are excited at near-infrared (NIR) wavelengths where biological molecules are optically transparent, and their luminesce in the visible and ultraviolet (UV) wavelength range is suitable for detection using complementary metal-oxide-semiconductor (CMOS) technology. These nanoparticles provide multiple sharp emission bands, long lifetimes, tunable emission, high photostability, and low cytotoxicity, which render them particularly useful for bio-imaging applications and multiplexed bioassays. This paper surveys several key concepts surrounding upconversion nanoparticles and the systems that detect and process the corresponding luminescence signals. The principle of photon upconversion, tuning of emission wavelengths, UCNP bioassays, and UCNP time-resolved techniques are described. Electronic readout systems for signal detection and processing suitable for UCNP luminescence using CMOS technology are discussed. This includes recent progress in miniaturized detectors, integrated spectral sensing, and high-precision time-domain circuits. Emphasis is placed on the physical attributes of UCNPs that map strongly to the technical features that CMOS devices excel in delivering, exploring the interoperability between the two technologies. PMID:25211198

  1. Radioisotope post-labeling upconversion nanophosphors for in vivo quantitative tracking.

    PubMed

    Sun, Yun; Liu, Qian; Peng, Juanjuan; Feng, Wei; Zhang, Yingjian; Yang, Pengyuan; Li, Fuyou

    2013-03-01

    Lanthanide based upconversion nanophosphors (UCNPs) attracted increasing attention for potential applications in bioimaging, while its in vivo behaviors are not clear until now due to no available quantification imaging tools. Herein, we developed a unique rare-earth cation-exchange-based postlabelling method to introduce (153)Sm into the lattice of UCNPs, providing this (153)Sm-postlabeling UCNP having bifunction of radioactive property and upconversion luminescence under excitation at 980 nm laser. This (153)Sm-postlabelling method shows rapid treatment time of <1 min, high labeling yield of >99%, and without usage of organic solvents. More importantly, this (153)Sm-postlabelling method is also suitable for most of rare earth nanoparticles to track their in vivo behaviors. The dynamic quantification studies of the in vivo fate of the rare-earth nanoparticles were further investigated by radioactive detection method such as single-photon emission computed tomography (SPECT) and gamma counter. The imaging results revealed that UCNPs were mainly captured by the mononuclear phagocyte system (liver and spleen). The amount of nanoparticles in liver arrived at its peak quicker and was about 15 fold of that in spleen. And the nanoparticles will be slowly excreted with the bile. Therefore, the concept of postlabeling (153)Sm onto lanthanide-based UCNPs may serve as a facile strategy of fabricating multifunctional nanoprobes for upconversion luminescence (UCL) and SPECT dual-modality imaging.

  2. Neurotoxin-conjugated upconversion nanoprobes for direct visualization of tumors under near-infrared irradiation.

    PubMed

    Yu, Xue-Feng; Sun, Zhengbo; Li, Min; Xiang, Yang; Wang, Qu-Quan; Tang, Fenfen; Wu, Yingliang; Cao, Zhijian; Li, Wenxin

    2010-11-01

    We report the development of neurotoxin-mediated upconversion nanoprobes for tumor targeting and visualization in living animals. The nanoprobes were synthesized by preparing polyethylenimine-coated hexagonal-phase NaYF(4):Yb,Er/Ce nanoparticles and conjugating them with recombinant chlorotoxin, a typical peptide neurotoxin that could bind with high specificity to many types of cancer cells. Nanoprobes that specifically targeted glioma cells were visualized by laser scanning upconversion fluorescence microscopy. Good probe biocompatibility was displayed with cellular and animal toxicity determinations. Animal studies were performed using Balb-c nude mice injected intravenously with the nanoprobes. The obtained high-contrast images demonstrated highly specific tumor binding and direct tumor visualization with bright red fluorescence under 980-nm near-infrared irradiation. The high sensitivity and high specificity of the neurotoxin-mediated upconversion nanoprobes and the simplification of the required optical device for tumor visualization suggest an approach that may help improve the effectiveness of the diagnostic and therapeutic modalities available for tumor patients.

  3. White light upconversion emissions in Er3+/Tm3+/Yb3+ tridoped oxyfluoride glass

    NASA Astrophysics Data System (ADS)

    Guan, Xiaoping; Xu, Wei; Zhu, Shuang; Song, Qiutong; Wu, Xijun; Liu, Hailong

    2015-10-01

    Rare earth ions doped glasses producing visible upconversion emissions are of great interest due to their potential applications in the photonics filed. In fact, practical application of upconversion emissions has been used to obtain color image displays and white light sources. However, there are few reports on the thermal effect on tuning the emission color of the RE doped materials. In this work, the Er3+/Tm3+/Yb3+ tridoped oxyfluoride glasses were prepared through high temperature solid-state method. Under a 980 nm diode laser excitation, the upconversion emissions from the samples were studied. At room-temperature, bright white luminescence, whose CIE chromaticity coordinate was about (0.28, 0.31), can be obtained when the excitation power was 120 mW. The emission color was changed by varying the intensity ratios between RGB bands, which are strongly dependent on the rare earth ions concentration. The temperature dependent color emissions were also investigated. As temperature increased, the intensities for the emission bands presented different decay rates, finally resulting in the changing of the CIE coordinate. When the temperature was 573 K, white light with color coordinate of (0.31, 0.33) was achieved, which matches well with the white reference (0.33, 0.33). The color tunability, high quality of white light and intense emission intensity make the transparent oxyfluoride glasses excellent candidates for applications in solid-state lighting.

  4. Demonstration of Passive W-Band Millimeter Wave Imaging Using Optical Upconversion Detection Methodology with Applications

    NASA Astrophysics Data System (ADS)

    Samluk, Jesse P.; Schuetz, Christopher A.; Dillon, Thomas; Martin, Richard D.; Stein, E. Lee; Mackrides, Daniel G.; Wilson, John; Robbins, Andrew; Shi, Shouyuan; Chen, Caihua; Yao, Peng; Shireen, Rownak; Macario, Julien; Prather, Dennis W.

    2012-11-01

    Millimeter wave (mmW) imaging has enjoyed a measure of success due to the unique properties of imaging in this spectral region, some of which are still being discovered. For example, a key advantage of mmW imaging is the ability to penetrate through various atmospheric obscurants, including fog, dust, sand, and smoke, due to its longer wavelengths as compared to visible or infrared imaging. Various methods of imaging with mmW energy exist, such as direct detection, downconversion, and upconversion, where this manuscript focuses on the latter. Until now, passive imaging using an optical upconversion method was limited to Q-band frequencies due to the lack of commercially available parts, namely a sufficiently high frequency optical modulator. To overcome this limitation, a custom-built modulator using in-house fabrication facilities was realized to allow imaging within the W-band frequency range (75-110 GHz). Therefore, in this manuscript we report new results of passive imaging in the W-band frequency range using a unique optical upconversion technique, where the higher frequency operation allows for greater detail in the imagery thus collected.

  5. The effect of surface coating on energy migration-mediated upconversion.

    PubMed

    Su, Qianqian; Han, Sanyang; Xie, Xiaoji; Zhu, Haomiao; Chen, Hongyu; Chen, Chih-Kai; Liu, Ru-Shi; Chen, Xueyuan; Wang, Feng; Liu, Xiaogang

    2012-12-26

    Lanthanide-doped upconversion nanoparticles have been the focus of a growing body of investigation because of their promising applications ranging from data storage to biological imaging and drug delivery. Here we present the rational design, synthesis, and characterization of a new class of core-shell upconversion nanoparticles displaying unprecedented optical properties. Specifically, we show that the epitaxial growth of an optically inert NaYF(4) layer around a lanthanide-doped NaGdF(4)@NaGdF(4) core-shell nanoparticle effectively prevents surface quenching of excitation energy. At room temperature, the energy migrates over Gd sublattices and is adequately trapped by the activator ions embedded in host lattices. Importantly, the NaYF(4) shell-coating strategy gives access to tunable upconversion emissions from a variety of activators (Dy(3+), Sm(3+), Tb(3+), and Eu(3+)) doped at very low concentrations (down to 1 mol %). Our mechanistic investigations make possible, for the first time, the realization of efficient emissions from Tb(3+) and Eu(3+) activators that are doped homogeneously with Yb(3+)/Tm(3+) ions. The advances on these luminescent nanomaterials offer exciting opportunities for important biological and energy applications.

  6. Simultaneous MMW generation and up-conversion for WDM-ROF systems based on FP laser

    NASA Astrophysics Data System (ADS)

    Zhang, Chan; Ning, TiGang; Li, Jing; Li, Chao; He, Xueqing; Pei, Li

    2016-10-01

    A new wavelength division multiplexing radio-over-fiber (WDM-ROF) scheme based on Fabry-Perot (FP) laser is proposed and demonstrated for simultaneous millimeter-wave (MMW) generation and up-conversion. The tunable optical comb generated by FP laser is served as a cost-effective WDM optical source in central station (CS) and it makes all-optical up-conversion process for all channels simple compared with using a DFB array. All modes from the FP laser are modulated simultaneously by a LiNbO3 Mach-Zehnder modulator (LN-MZM) then. We have systematically compared the performances of MMW generation and up-conversion using LN-MZM based on different modulation schemes. A reflective semiconductor optical amplifiers (RSOA) is used both for the downstream modulation of each channel and for the reduction of mode partition noise (MPN) induced from FP laser. In the scheme, the multiple optical carrier suppression (OCS) modulation shows the highest receiver sensitivity and smallest power penalty over long-distance delivery. In the numerical simulation, 7 WDM channels each carrying 2.5 Gb/s baseband signal have been up-converted to 60 GHz simultaneously with good performance over 25 km single mode fiber (SMF) transmission.

  7. The intersection of CMOS microsystems and upconversion nanoparticles for luminescence bioimaging and bioassays.

    PubMed

    Wei, Liping; Doughan, Samer; Han, Yi; DaCosta, Matthew V; Krull, Ulrich J; Ho, Derek

    2014-09-10

    Organic fluorophores and quantum dots are ubiquitous as contrast agents for bio-imaging and as labels in bioassays to enable the detection of biological targets and processes. Upconversion nanoparticles (UCNPs) offer a different set of opportunities as labels in bioassays and for bioimaging. UCNPs are excited at near-infrared (NIR) wavelengths where biological molecules are optically transparent, and their luminesce in the visible and ultraviolet (UV) wavelength range is suitable for detection using complementary metal-oxide-semiconductor (CMOS) technology. These nanoparticles provide multiple sharp emission bands, long lifetimes, tunable emission, high photostability, and low cytotoxicity, which render them particularly useful for bio-imaging applications and multiplexed bioassays. This paper surveys several key concepts surrounding upconversion nanoparticles and the systems that detect and process the corresponding luminescence signals. The principle of photon upconversion, tuning of emission wavelengths, UCNP bioassays, and UCNP time-resolved techniques are described. Electronic readout systems for signal detection and processing suitable for UCNP luminescence using CMOS technology are discussed. This includes recent progress in miniaturized detectors, integrated spectral sensing, and high-precision time-domain circuits. Emphasis is placed on the physical attributes of UCNPs that map strongly to the technical features that CMOS devices excel in delivering, exploring the interoperability between the two technologies.

  8. Composition tuning the upconversion emission in NaYF4:Yb/Tm hexaplate nanocrystals.

    PubMed

    Zhang, Hua; Li, Yujing; Lin, Yungchen; Huang, Yu; Duan, Xiangfeng

    2011-03-01

    Single crystal hexagonal NaYF4:Yb/Tm nanocrystals have been synthesized with uniform size, morphology and controlled chemical composition. Spectroscopic studies show that these nanocrystals exhibit strong energy upconversion emission when excited with a 980 nm diode laser, with two primary emission peaks centered around 452 nm and 476 nm. Importantly, the overall and relative emission intensity at these wavelengths can be readily tuned by controlling the concentration of the trivalent rare earth element dopants at the beginning of the synthesis which has been confirmed by EDX for the first time. Through systematic studies, the optimum rare earth ion doping concentration can be determined for the strongest emission intensity at the selected peak(s). Confocal microscopy studies show that the upconversion emission from individual NCs can be readily visualized. These studies demonstrate a rational approach for fine tuning the upconversion properties in rare-earth doped nanostructures and can broadly impact areas ranging from energy harvesting, energy conversion to biomedical imaging and therapeutics. PMID:21264435

  9. Multicolor upconversion emissions in Tm 3+/Er3+ codoped tellurite photonic microwire between silica fiber tapers.

    PubMed

    Chen, Nan-Kuang; Kuan, Pei-Wen; Zhang, Junjie; Zhang, Liyan; Hu, Lili; Lin, Chinlon; Tong, Limin

    2010-12-01

    We report multicolor upconversion emissions including the blue-violet, green, and red lights in a Tm 3+/Er3+codoped tellurite glass photonic microwire between two silica fiber tapers. A silica fiber is tapered until its evanescent field is exposed and then angled-cleaved at the tapered center to divide the tapered fibers into two parts. A tellurite glass is melted by a gas flame to cluster into a sphere at the tip of one tapered fiber. The other angled-cleaved tapered fiber is blended into the melted tellurite glass. When the tellurite glass is melted, the two silica fiber tapers are simultaneously moving outwards to draw the tellurite glass into a microwire in between. The advantage of angled-cleaving on fiber tapers is to avoid cavity resonances in high index photonic microwire. Thus, the broadband white light can be transmitted between silica fibers and a special optical property like high intensity upconversion emission can be achieved. A cw 1064 nm Nd:YAG laser light is launched into the Tm 3+/Er3+ codoped tellurite microwire through a silica fiber taper to generate the multicolor upconversion emissions, including the blue-violet, green, and red lights, simultaneously. PMID:21164907

  10. Origin of the infrared to visible upconversion mechanisms in Nd 3+-doped potassium lead chloride crystal

    NASA Astrophysics Data System (ADS)

    Mendioroz, A.; Balda, R.; Al-Saleh, M.; Fernández, J.

    2005-10-01

    The infrared to visible upconversion mechanisms of Nd3+ ions in potassium lead chloride crystal have been investigated at liquid nitrogen temperature (LNT). We have observed upconversion luminescence when pumping into both 4F3/2 and 4F5/2 bands and off-resonance, at 851 and 856 nm. The main bands appearing in the emission spectra are two blue bands located at 420 and 435 nm, corresponding to transitions 4D3/2 → 4I13/2 and 2P1/2 → 4I9/2 respectively, and green, orange and red emissions, located at 535, 595 and 668 nm, corresponding to 4G7/2-4G9/2 → 4I9/2, 4I11/2, 4I13/2 transitions, respectively. The results show that, upon excitation of either the 4F3/2 or 4F5/2 band at LNT, two- and three-body energy transfer upconversion process are responsible for the emissions coming from levels 4G7/2-4G9/2 (535, 595, and 668 nm) and 4D3/2 (420 nm), respectively. However, the experimental data indicate that the mechanisms leading to the luminescence coming from level 2P1/2 depend on the pumping wavelength and sample temperature.

  11. Enhancing Solar Cell Efficiencies through 1-D Nanostructures

    PubMed Central

    2009-01-01

    The current global energy problem can be attributed to insufficient fossil fuel supplies and excessive greenhouse gas emissions resulting from increasing fossil fuel consumption. The huge demand for clean energy potentially can be met by solar-to-electricity conversions. The large-scale use of solar energy is not occurring due to the high cost and inadequate efficiencies of existing solar cells. Nanostructured materials have offered new opportunities to design more efficient solar cells, particularly one-dimensional (1-D) nanomaterials for enhancing solar cell efficiencies. These 1-D nanostructures, including nanotubes, nanowires, and nanorods, offer significant opportunities to improve efficiencies of solar cells by facilitating photon absorption, electron transport, and electron collection; however, tremendous challenges must be conquered before the large-scale commercialization of such cells. This review specifically focuses on the use of 1-D nanostructures for enhancing solar cell efficiencies. Other nanostructured solar cells or solar cells based on bulk materials are not covered in this review. Major topics addressed include dye-sensitized solar cells, quantum-dot-sensitized solar cells, and p-n junction solar cells.

  12. Constructing 3D interaction maps from 1D epigenomes

    PubMed Central

    Zhu, Yun; Chen, Zhao; Zhang, Kai; Wang, Mengchi; Medovoy, David; Whitaker, John W.; Ding, Bo; Li, Nan; Zheng, Lina; Wang, Wei

    2016-01-01

    The human genome is tightly packaged into chromatin whose functional output depends on both one-dimensional (1D) local chromatin states and three-dimensional (3D) genome organization. Currently, chromatin modifications and 3D genome organization are measured by distinct assays. An emerging question is whether it is possible to deduce 3D interactions by integrative analysis of 1D epigenomic data and associate 3D contacts to functionality of the interacting loci. Here we present EpiTensor, an algorithm to identify 3D spatial associations within topologically associating domains (TADs) from 1D maps of histone modifications, chromatin accessibility and RNA-seq. We demonstrate that active promoter–promoter, promoter–enhancer and enhancer–enhancer associations identified by EpiTensor are highly concordant with those detected by Hi-C, ChIA-PET and eQTL analyses at 200 bp resolution. Moreover, EpiTensor has identified a set of interaction hotspots, characterized by higher chromatin and transcriptional activity as well as enriched TF and ncRNA binding across diverse cell types, which may be critical for stabilizing the local 3D interactions. PMID:26960733

  13. Constructing 3D interaction maps from 1D epigenomes.

    PubMed

    Zhu, Yun; Chen, Zhao; Zhang, Kai; Wang, Mengchi; Medovoy, David; Whitaker, John W; Ding, Bo; Li, Nan; Zheng, Lina; Wang, Wei

    2016-01-01

    The human genome is tightly packaged into chromatin whose functional output depends on both one-dimensional (1D) local chromatin states and three-dimensional (3D) genome organization. Currently, chromatin modifications and 3D genome organization are measured by distinct assays. An emerging question is whether it is possible to deduce 3D interactions by integrative analysis of 1D epigenomic data and associate 3D contacts to functionality of the interacting loci. Here we present EpiTensor, an algorithm to identify 3D spatial associations within topologically associating domains (TADs) from 1D maps of histone modifications, chromatin accessibility and RNA-seq. We demonstrate that active promoter-promoter, promoter-enhancer and enhancer-enhancer associations identified by EpiTensor are highly concordant with those detected by Hi-C, ChIA-PET and eQTL analyses at 200 bp resolution. Moreover, EpiTensor has identified a set of interaction hotspots, characterized by higher chromatin and transcriptional activity as well as enriched TF and ncRNA binding across diverse cell types, which may be critical for stabilizing the local 3D interactions. PMID:26960733

  14. Development of 1D Liner Compression Code for IDL

    NASA Astrophysics Data System (ADS)

    Shimazu, Akihisa; Slough, John; Pancotti, Anthony

    2015-11-01

    A 1D liner compression code is developed to model liner implosion dynamics in the Inductively Driven Liner Experiment (IDL) where FRC plasmoid is compressed via inductively-driven metal liners. The driver circuit, magnetic field, joule heating, and liner dynamics calculations are performed at each time step in sequence to couple these effects in the code. To obtain more realistic magnetic field results for a given drive coil geometry, 2D and 3D effects are incorporated into the 1D field calculation through use of correction factor table lookup approach. Commercial low-frequency electromagnetic fields solver, ANSYS Maxwell 3D, is used to solve the magnetic field profile for static liner condition at various liner radius in order to derive correction factors for the 1D field calculation in the code. The liner dynamics results from the code is verified to be in good agreement with the results from commercial explicit dynamics solver, ANSYS Explicit Dynamics, and previous liner experiment. The developed code is used to optimize the capacitor bank and driver coil design for better energy transfer and coupling. FRC gain calculations are also performed using the liner compression data from the code for the conceptual design of the reactor sized system for fusion energy gains.

  15. Molecular characterization of zebrafish Oatp1d1 (Slco1d1), a novel organic anion-transporting polypeptide.

    PubMed

    Popovic, Marta; Zaja, Roko; Fent, Karl; Smital, Tvrtko

    2013-11-22

    The organic anion-transporting polypeptide (OATP/Oatp) superfamily includes a group of polyspecific transporters that mediate transport of large amphipathic, mostly anionic molecules across cell membranes of eukaryotes. OATPs/Oatps are involved in the disposition and elimination of numerous physiological and foreign compounds. However, in non-mammalian species, the functional properties of Oatps remain unknown. We aimed to elucidate the role of Oatp1d1 in zebrafish to gain insights into the functional and structural evolution of the OATP1/Oatp1 superfamily. We show that diversification of the OATP1/Oatp1 family occurs after the emergence of jawed fish and that the OATP1A/Oatp1a and OATP1B/Oatp1b subfamilies appeared at the root of tetrapods. The Oatp1d subfamily emerged in teleosts and is absent in tetrapods. The zebrafish Oatp1d1 is similar to mammalian OATP1A/Oatp1a and OATP1B/Oatp1b members, with the main physiological role in transport and balance of steroid hormones. Oatp1d1 activity is dependent upon pH gradient, which could indicate bicarbonate exchange as a mode of transport. Our analysis of evolutionary conservation and structural properties revealed that (i) His-79 in intracellular loop 3 is conserved within OATP1/Oatp1 family and is crucial for the transport activity; (ii) N-glycosylation impacts membrane targeting and is conserved within the OATP1/Oatp1 family with Asn-122, Asn-133, Asn-499, and Asn-512 residues involved; (iii) the evolutionarily conserved cholesterol recognition interaction amino acid consensus motif is important for membrane localization; and (iv) Oatp1d1 is present in dimeric and possibly oligomeric form in the cell membrane. In conclusion, we describe the first detailed characterization of a new Oatp transporter in zebrafish, offering important insights into the functional evolution of the OATP1/Oatp1 family and the physiological role of Oatp1d1.

  16. Upconversion luminescent logic gates and turn-on sensing of glutathione based on two-photon excited quantum dots conjugated with dopamine.

    PubMed

    Gui, Rijun; Jin, Hui; Liu, Xifeng; Wang, Zonghua; Zhang, Feifei; Xia, Jianfei; Yang, Min; Bi, Sai

    2014-12-01

    Under the two-photon excitation, upconversion luminescent "INHIBIT" and "OR" logic gates of water-dispersed CdTe quantum dots (QDs) were constituted by conjugating the QDs with dopamine. This facilitated the development of a novel QDs-based upconversion luminescent probe for efficient turn-on sensing of glutathione. PMID:25325081

  17. Effect of Mn and Cr doping on the up-conversion luminescence from NaYF4:Yb3+,Er3+

    NASA Astrophysics Data System (ADS)

    Tuomisto, Minnea; Palo, Emilia; Laihinen, Tero; Hyppänen, Iko; Lastusaari, Mika; Swart, Hendrik C.; Hölsä, Jorma

    2016-09-01

    The up-conversion luminescence where the absorption of two or more low-energy photons results in emission of a higher-energy photon has been highly effective in certain applications such as bioanalytical assays. Currently one of the most efficient up-converting materials is the NaYF4:Yb3+,Er3+. However, some applications (e.g. solar cells) still require improvement of the up-conversion efficiency in order to have actual practical use. Therefore, it is important to enhance the performance of the materials. In this work, the effect of Mn and Cr doping on the up-conversion luminescence of NaYF4:Yb3+,Er3+ was studied. The materials were prepared using the co-precipitation method and the ratios of the doping ions were optimized for best up-conversion intensity. The as-prepared materials showed very similar sizes and morphologies. Cr co-doping was observed to increase the up-conversion luminescence whereas the addition of Mn resulted in quenching. Up-conversion luminescence was also measured with different excitation power densities and the results suggested that Cr co-doping enables the up-conversion in lower power densities than without Cr co-doping. Furthermore, the reasons for the changes in up-conversion luminescence intensity were discussed.

  18. Single-layer MoS2 nanosheet grafted upconversion nanoparticles for near-infrared fluorescence imaging-guided deep tissue cancer phototherapy.

    PubMed

    Han, Jianyu; Xia, Hongping; Wu, Yafeng; Kong, Shik Nie; Deivasigamani, Amudha; Xu, Rong; Hui, Kam M; Kang, Yuejun

    2016-04-21

    A multifunctional nanostructure is prepared by covalently grafting upconversion nanoparticles (UCNPs) with chitosan functionalized MoS2 (MoS2-CS) and folic acid (FA) and then loading phthalocyanine (ZnPc) on the surface of MoS2, which integrates photodynamic therapy (PDT) with photothermal therapy (PTT) and upconversion luminescence imaging into one system for enhanced antitumor efficiency. PMID:27035265

  19. Highly improved upconversion luminescence in NaGd(WO₄)₂:Yb³⁺/Tm³⁺ inverse opal photonic crystals.

    PubMed

    Wang, Yunfeng; Xu, Wen; Cui, Shaobo; Xu, Sai; Yin, Ze; Song, Hongwei; Zhou, Pingwei; Liu, Xiaoyan; Xu, Lin; Cui, Haining

    2015-01-28

    The upconversion luminescence (UCL) of rare earth (RE) ions doped nanomaterials has attracted extensive interest because of its wide and great potential applications. However, the lower UCL efficiency is still an obstacle for real applications. Photonic modulation is a novel way to improve the efficiency of UCL. In this work, NaGd(WO4)2:Yb(3+)/Tm(3+) inverse opal photonic crystals (IOPCs) were fabricated through the polymethylmethacrylate (PMMA) template and the modification of the IOPC structure on the emission spectra and dynamics of Tm(3+) ions was systemically studied. It is interesting to observe that in the IOPCs, the high-order UCL (1)D2-(3)H6/(3)F4 was relatively enhanced. At the same time, the local thermal effect induced by laser irradiation was suppressed. Furthermore, the overall intensity ratio of visible UCL to near-infrared (NIR) down-conversion luminescence (DCL) was 2.8-8 times improved than that of the grinded reference (REF) and independent of the photonic stop band (PSB). The studies on UCL dynamics indicated that the nonradiative transition rate of Tm(3+) was considerably suppressed. The facts above indicated that in the IOPCs the UCL efficiency of Tm(3+) was largely improved due to the periodic macroporous structure.

  20. Highly improved upconversion luminescence in NaGd(WO₄)₂:Yb³⁺/Tm³⁺ inverse opal photonic crystals.

    PubMed

    Wang, Yunfeng; Xu, Wen; Cui, Shaobo; Xu, Sai; Yin, Ze; Song, Hongwei; Zhou, Pingwei; Liu, Xiaoyan; Xu, Lin; Cui, Haining

    2015-01-28

    The upconversion luminescence (UCL) of rare earth (RE) ions doped nanomaterials has attracted extensive interest because of its wide and great potential applications. However, the lower UCL efficiency is still an obstacle for real applications. Photonic modulation is a novel way to improve the efficiency of UCL. In this work, NaGd(WO4)2:Yb(3+)/Tm(3+) inverse opal photonic crystals (IOPCs) were fabricated through the polymethylmethacrylate (PMMA) template and the modification of the IOPC structure on the emission spectra and dynamics of Tm(3+) ions was systemically studied. It is interesting to observe that in the IOPCs, the high-order UCL (1)D2-(3)H6/(3)F4 was relatively enhanced. At the same time, the local thermal effect induced by laser irradiation was suppressed. Furthermore, the overall intensity ratio of visible UCL to near-infrared (NIR) down-conversion luminescence (DCL) was 2.8-8 times improved than that of the grinded reference (REF) and independent of the photonic stop band (PSB). The studies on UCL dynamics indicated that the nonradiative transition rate of Tm(3+) was considerably suppressed. The facts above indicated that in the IOPCs the UCL efficiency of Tm(3+) was largely improved due to the periodic macroporous structure. PMID:25493336

  1. Multispectral upconversion luminescence intensity ratios for ascertaining the tissue imaging depth

    NASA Astrophysics Data System (ADS)

    Liu, Kai; Wang, Yu; Kong, Xianggui; Liu, Xiaomin; Zhang, Youlin; Tu, Langping; Ding, Yadan; Aalders, Maurice C. G.; Buma, Wybren Jan; Zhang, Hong

    2014-07-01

    Upconversion nanoparticles (UCNPs) have in recent years emerged as excellent contrast agents for in vivo luminescence imaging of deep tissues. But information abstracted from these images is in most cases restricted to 2-dimensions, without the depth information. In this work, a simple method has been developed to accurately ascertain the tissue imaging depth based on the relative luminescence intensity ratio of multispectral NaYF4:Yb3+,Er3+ UCNPs. A theoretical mode was set up, where the parameters in the quantitative relation between the relative intensities of the upconversion luminescence spectra and the depth of the UCNPs were determined using tissue mimicking liquid phantoms. The 540 nm and 650 nm luminescence intensity ratios (G/R ratio) of NaYF4:Yb3+,Er3+ UCNPs were monitored following excitation path (Ex mode) and emission path (Em mode) schemes, respectively. The model was validated by embedding NaYF4:Yb3+,Er3+ UCNPs in layered pork muscles, which demonstrated a very high accuracy of measurement in the thickness up to centimeter. This approach shall promote significantly the power of nanotechnology in medical optical imaging by expanding the imaging information from 2-dimensional to real 3-dimensional.Upconversion nanoparticles (UCNPs) have in recent years emerged as excellent contrast agents for in vivo luminescence imaging of deep tissues. But information abstracted from these images is in most cases restricted to 2-dimensions, without the depth information. In this work, a simple method has been developed to accurately ascertain the tissue imaging depth based on the relative luminescence intensity ratio of multispectral NaYF4:Yb3+,Er3+ UCNPs. A theoretical mode was set up, where the parameters in the quantitative relation between the relative intensities of the upconversion luminescence spectra and the depth of the UCNPs were determined using tissue mimicking liquid phantoms. The 540 nm and 650 nm luminescence intensity ratios (G/R ratio) of NaYF4:Yb3

  2. Dual modal in vivo imaging using upconversion luminescence and enhanced computed tomography properties

    NASA Astrophysics Data System (ADS)

    Zhang, Guo; Liu, Yanlan; Yuan, Qinghai; Zong, Chenghua; Liu, Jianhua; Lu, Lehui

    2011-10-01

    In vivo upconversion luminescence (UCL) imaging, exhibiting favorable characteristics such as high photostability, no blinking, sharp emission lines, and long lifetimes, is recognized as the excellent and significant photoluminescence imaging for the future. To develop the imaging system with high visual sensitivity and tissue penetration, the functional molecules with X-ray computed tomography (CT) contrast were grafted onto upconversion nanoparticles to obtain β-NaYF4:18% Yb3+,2%Er3+@SiO2-I/PEG (UCNPs@SiO2-I/PEG) nanoprobes. These nanoprobes are water-soluble, have low cytotoxicity, and possess excellent UCL and remarkable CT contrast. Of particular note is that, besides the element iodine, rare earth elements (Y, Yb, and Er) present in the nanoprobes also show CT contrast. Moreover, no background autofluorescence signal is found in in vivo UCL images. We believe that these nanoprobes with dual modal in vivo imaging of UCL and CT can serve as a promising platform for clinical diagnosis or biomedical studies.In vivo upconversion luminescence (UCL) imaging, exhibiting favorable characteristics such as high photostability, no blinking, sharp emission lines, and long lifetimes, is recognized as the excellent and significant photoluminescence imaging for the future. To develop the imaging system with high visual sensitivity and tissue penetration, the functional molecules with X-ray computed tomography (CT) contrast were grafted onto upconversion nanoparticles to obtain β-NaYF4:18% Yb3+,2%Er3+@SiO2-I/PEG (UCNPs@SiO2-I/PEG) nanoprobes. These nanoprobes are water-soluble, have low cytotoxicity, and possess excellent UCL and remarkable CT contrast. Of particular note is that, besides the element iodine, rare earth elements (Y, Yb, and Er) present in the nanoprobes also show CT contrast. Moreover, no background autofluorescence signal is found in in vivo UCL images. We believe that these nanoprobes with dual modal in vivo imaging of UCL and CT can serve as a promising

  3. Upconversion Luminescence Properties of Y2Mo4O15: Yb3+, Er3+ by Solid State Combustion Method.

    PubMed

    Jiang, Tao; Xing, Mingming; Fu, Yao; Tian, Ying; Luo, Xixian

    2016-04-01

    The Yb3+ and Er3+ co-doped yttrium molybdenum oxide upconversion phosphors were prepared by the solid state combustion method using urea as fuel at ignition temperature of 550 °C. The upconversion phosphors were characterized by X-ray diffraction (XRD), scanning electronic microscope (SEM), and photoluminescence spectra XRD results revealed the samples were pure monoclinic Y2Mo4O15 phases when the sintering temperature was 700 °C. SEM micrographs illustrated particle size distribution was almost uniform with an average particle diameter of about 0.5-1.0 µm. The obtained Y2MO4O15: Yb3+, Er3+ presents bright and pure green upconversion luminescence during daylight pumping under 980 nm LD. According to the analysis of upconversion luminescent mechanism, the cross relaxation processes of Er3+ ions restrained the electron population of red emission energy level, which not only increased the green light upconversion emissions fluorescent branching ratio (IGIR = 153:1) but also enhanced the efficiency and purity of green light emissions. PMID:27451756

  4. Broadband-sensitive cooperative upconversion emission of La(Ga0.5Sc0.5)O3:Er,Ni,Nb

    NASA Astrophysics Data System (ADS)

    Takeda, Yasuhiko; Mizuno, Shintaro; Nath Luitel, Hom; Yamanaka, Ken-ichi

    2016-11-01

    We systematically conducted time-resolved photoluminescence measurements on La(Ga0.5Sc0.5)O3:Er,Ni,Nb to elucidate the dominant mechanism of Ni2+-sensitized Er3+ upconversion emission at approximately 0.98 µm under 1.0–1.45-µm excitation, which could significantly improve the conversion efficiency of crystalline silicon solar cells. After detailed analysis using rate equations describing the energy transfer involved in the Ni2+ and Er3+ and upconversion, we concluded that the upconversion emission is dominated by the excitation of two Er3+ emitters due to the resonance energy transfer from two Ni2+ sensitizers, followed by further excitation to the initial state of the upconversion emission caused by another energy transfer between the two first-excited Er3+, i.e., cooperative upconversion.

  5. 3-Dimensional photonic crystal surface enhanced upconversion emission for improved near-infrared photoresponse

    NASA Astrophysics Data System (ADS)

    Niu, Wenbin; Su, Liap Tat; Chen, Rui; Chen, Hu; Wang, Yi; Palaniappan, Alagappan; Sun, Handong; Yoong Tok, Alfred Iing

    2013-12-01

    The enhancement of upconversion luminescence of lanthanide-ion doped fluoride upconversion nanoparticles (UCNPs) is particularly important and highly required for their myriad applications in sensing, photoelectronic devices and bio-imaging. In this work, the amplification of luminescence in NaYF4:Yb/Er and NaYF4:Yb/Tm UCNPs in close proximity to the three-dimensional photonic crystal (3D PC) surface for improved near-infrared photoresponse of a carbon nanotube-based phototransistor is reported. The self-assembled opal 3D PCs with polystyrene sphere sizes of 200, 290 and 360 nm that exhibit reflection peaks of 450, 650 and 800 nm respectively were used for upconversion enhancement, and around 30 times enhancement was obtained for NaYF4:Yb/Er and NaYF4:Yb/Tm UCNPs. Time-resolved upconversion emission and 3D PC transmittance-dependent upconversion enhancement reveal that the enhanced absorption and the extraction effects, resulting from the enhanced non-resonant pump excitation field and the strong coherent scattering provided by 3D PCs respectively, are responsible for the large enhancement. As a proof-of-concept experiment, the prepared 3D PC/NaYF4:Yb/Tm UCNP coupled material layer was introduced into the carbon nanotube-based phototransistor. It is shown that the photoresponsivity of the device to near-infrared light was improved by 10 times with respect to the control device with carbon nanotubes only, which reveals the promising applications of this coupled material in photoelectronic devices such as photovoltaics and other types of phototransistors.The enhancement of upconversion luminescence of lanthanide-ion doped fluoride upconversion nanoparticles (UCNPs) is particularly important and highly required for their myriad applications in sensing, photoelectronic devices and bio-imaging. In this work, the amplification of luminescence in NaYF4:Yb/Er and NaYF4:Yb/Tm UCNPs in close proximity to the three-dimensional photonic crystal (3D PC) surface for improved

  6. Multicolor tunability and upconversion enhancement of fluoride nanoparticles by oxygen dopant

    NASA Astrophysics Data System (ADS)

    Niu, Wenbin; Wu, Suli; Zhang, Shufen; Su, Liap Tat; Tok, Alfred Iing Yoong

    2013-08-01

    The ability to manipulate the upconversion luminescence of lanthanide-ion doped fluoride upconversion nanoparticles (UCNPs) is particularly important and highly desired due to their wide applications in color displays, multiplexing bioassays and multicolor imaging. Here, we developed a strategy for simultaneously tuning color output and enhancing upconversion emission of Yb/Er doped fluoride UCNPs, based on adjusting the oxygen doping level. The synthesis of multicolored multifunctional NaGdF4:Yb,Er UCNPs was used as the model host system to demonstrate this protocol. Ammonium nitrate (NH4NO3) was used as the oxygen source and added into the reaction system at the beginning stage of nucleation and growth process of fluoride UCNPs, which facilitates the formation of enough oxygen atoms and the diffusion of these into the fluoride host matrix. The results revealed that multicolour output and upconversion enhancement mainly resulted from the variation of phonon energy and crystal field symmetry of the host lattice, respectively. This strategy can be further expanded to other fluoride host matrices. As an example of an application, multicolored UCNPs were used as a color converter in light emitting diodes, which can effectively convert near-infrared light into visible light. It is expected that these multicolored UCNPs will be promising for applications in multiplexing biodetection, bioimaging (optical and magnetic resonance imaging) and other optical technologies, and the present method for the control of O2- doping may also be used in other functional nanomaterials.The ability to manipulate the upconversion luminescence of lanthanide-ion doped fluoride upconversion nanoparticles (UCNPs) is particularly important and highly desired due to their wide applications in color displays, multiplexing bioassays and multicolor imaging. Here, we developed a strategy for simultaneously tuning color output and enhancing upconversion emission of Yb/Er doped fluoride UCNPs, based

  7. Extended-Range Ultrarefractive 1D Photonic Crystal Prisms

    NASA Technical Reports Server (NTRS)

    Ting, David Z.

    2007-01-01

    A proposal has been made to exploit the special wavelength-dispersive characteristics of devices of the type described in One-Dimensional Photonic Crystal Superprisms (NPO-30232) NASA Tech Briefs, Vol. 29, No. 4 (April 2005), page 10a. A photonic crystal is an optical component that has a periodic structure comprising two dielectric materials with high dielectric contrast (e.g., a semiconductor and air), with geometrical feature sizes comparable to or smaller than light wavelengths of interest. Experimental superprisms have been realized as photonic crystals having three-dimensional (3D) structures comprising regions of amorphous Si alternating with regions of SiO2, fabricated in a complex process that included sputtering. A photonic crystal of the type to be exploited according to the present proposal is said to be one-dimensional (1D) because its contrasting dielectric materials would be stacked in parallel planar layers; in other words, there would be spatial periodicity in one dimension only. The processes of designing and fabricating 1D photonic crystal superprisms would be simpler and, hence, would cost less than do those for 3D photonic crystal superprisms. As in 3D structures, 1D photonic crystals may be used in applications such as wavelength-division multiplexing. In the extended-range configuration, it is also suitable for spectrometry applications. As an engineered structure or artificially engineered material, a photonic crystal can exhibit optical properties not commonly found in natural substances. Prior research had revealed several classes of photonic crystal structures for which the propagation of electromagnetic radiation is forbidden in certain frequency ranges, denoted photonic bandgaps. It had also been found that in narrow frequency bands just outside the photonic bandgaps, the angular wavelength dispersion of electromagnetic waves propagating in photonic crystal superprisms is much stronger than is the angular wavelength dispersion obtained

  8. Non-linearity in Bayesian 1-D magnetotelluric inversion

    NASA Astrophysics Data System (ADS)

    Guo, Rongwen; Dosso, Stan E.; Liu, Jianxin; Dettmer, Jan; Tong, Xiaozhong

    2011-05-01

    This paper applies a Bayesian approach to examine non-linearity for the 1-D magnetotelluric (MT) inverse problem. In a Bayesian formulation the posterior probability density (PPD), which combines data and prior information, is interpreted in terms of parameter estimates and uncertainties, which requires optimizing and integrating the PPD. Much work on 1-D MT inversion has been based on (approximate) linearized solutions, but more recently fully non-linear (numerical) approaches have been applied. This paper directly compares results of linearized and non-linear uncertainty estimation for 1-D MT inversion; to do so, advanced methods for both approaches are applied. In the non-linear formulation used here, numerical optimization is carried out using an adaptive-hybrid algorithm. Numerical integration applies Metropolis-Hastings sampling, rotated to a principal-component parameter space for efficient sampling of correlated parameters, and employing non-unity sampling temperatures to ensure global sampling. Since appropriate model parametrizations are generally not known a priori, both under- and overparametrized approaches are considered. For underparametrization, the Bayesian information criterion is applied to determine the number of layers consistent with the resolving power of the data. For overparametrization, prior information is included which favours simple structure in a manner similar to regularized inversion. The data variance and/or trade-off parameter regulating data and prior information are treated in several ways, including applying fixed optimal estimates (an empirical Bayesian approach) or including them as hyperparameters in the sampling (hierarchical Bayesian). The latter approach has the benefit of accounting for the uncertainty in the hyperparameters in estimating model parameter uncertainties. Non-linear and linearized inversion results are compared for synthetic test cases and for the measured COPROD1 MT data by considering marginal probability

  9. Viscous behavior in a quasi-1D fractal cluster glass.

    PubMed

    Etzkorn, S J; Hibbs, Wendy; Miller, Joel S; Epstein, A J

    2002-11-11

    The spin glass transition of a quasi-1D organic-based magnet ([MnTPP][TCNE]) is explored using both ac and dc measurements. A scaling analysis of the ac susceptibility shows a spin glass transition near 4 K, with a viscous decay of the thermoremanent magnetization recorded above 4 K. We propose an extension to a fractal cluster model of spin glasses that determines the dimension of the spin clusters (D) ranging from approximately 0.8 to over 1.5 as the glass transition is approached. Long-range dipolar interactions are suggested as the origin of this low value for the apparent lower critical dimension.

  10. Practical variational tomography for critical 1D systems

    NASA Astrophysics Data System (ADS)

    Lee, Jong Yeon; Landon-Cardinal, Olivier

    2015-03-01

    We further investigate a recently introduced efficient quantum state reconstruction procedure targeted to states well-approximated by the multi-scale entanglement renormalization ansatz (MERA). First, we introduce an improved optimization scheme that can be easily generalized for MERA states with larger bond dimension. Second, we provide a detailed analysis of the error propagation and quantify how it affects the distance between the experimental state and the reconstructed state. Third, we explain how to bound this distance using local data, providing an efficient scalable certification method. Fourth, we examine the performance of MERA tomography on the ground states of several 1D critical models.

  11. Structural stability of a 1D compressible viscoelastic fluid model

    NASA Astrophysics Data System (ADS)

    Huo, Xiaokai; Yong, Wen-An

    2016-07-01

    This paper is concerned with a compressible viscoelastic fluid model proposed by Öttinger. Although the model has a convex entropy, the Hessian matrix of the entropy does not symmetrize the system of first-order partial differential equations due to the non-conservative terms in the constitutive equation. We show that the corresponding 1D model is symmetrizable hyperbolic and dissipative and satisfies the Kawashima condition. Based on these, we prove the global existence of smooth solutions near equilibrium and justify the compatibility of the model with the Navier-Stokes equations.

  12. Nonlocal Order Parameters for the 1D Hubbard Model

    NASA Astrophysics Data System (ADS)

    Montorsi, Arianna; Roncaglia, Marco

    2012-12-01

    We characterize the Mott-insulator and Luther-Emery phases of the 1D Hubbard model through correlators that measure the parity of spin and charge strings along the chain. These nonlocal quantities order in the corresponding gapped phases and vanish at the critical point Uc=0, thus configuring as hidden order parameters. The Mott insulator consists of bound doublon-holon pairs, which in the Luther-Emery phase turn into electron pairs with opposite spins, both unbinding at Uc. The behavior of the parity correlators is captured by an effective free spinless fermion model.

  13. Deconvolution/identification techniques for 1-D transient signals

    SciTech Connect

    Goodman, D.M.

    1990-10-01

    This paper discusses a variety of nonparametric deconvolution and identification techniques that we have developed for application to 1-D transient signal problems. These methods are time-domain techniques that use direct methods for matrix inversion. Therefore, they are not appropriate for large data'' problems. These techniques involve various regularization methods and permit the use of certain kinds of a priori information in estimating the unknown. These techniques have been implemented in a package using standard FORTRAN that should make the package readily transportable to most computers. This paper is also meant to be an instruction manual for the package. 25 refs., 17 figs., 1 tab.

  14. Coherent thermal conductance of 1-D photonic crystals

    NASA Astrophysics Data System (ADS)

    Tschikin, Maria; Ben-Abdallah, Philippe; Biehs, Svend-Age

    2012-10-01

    We present an exact calculation of coherent thermal conductance in 1-D multilayer photonic crystals using the S-matrix method. In particular, we study the thermal conductance in a bilayer structure of Si/vacuum or Al2O3/vacuum slabs by means of the exact radiative heat flux expression. Based on the results obtained for the Al2O3/vacuum structure we show by comparison with previous works that the material losses and (localized) surface modes supported by the inner layers play a fundamental role and cannot be omitted in the definition of thermal conductance. Our results could have significant implications in the conception of efficient thermal barriers.

  15. A simple quasi-1D model of Fibonacci anyons

    NASA Astrophysics Data System (ADS)

    Aasen, David; Mong, Roger; Clarke, David; Alicea, Jason; Fendley, Paul

    2015-03-01

    There exists various ways of understanding the topological properties of Ising anyons--from simple free-fermion toy models to formal topological quantum field theory. For other types of anyons simple toy models rarely exist; their properties have to be obtained using formal self-consistency relations. We explore a family of gapped 1D local bosonic models that in a certain limit become trivial to solve and provide an intuitive picture for Fibonacci anyons. One can interpret this model as a quasi-1D wire that forms the building block of a 2D topological phase with Fibonacci anyons. With this interpretation all topological properties of the Fibonacci anyons become manifest including ground state degeneracy and braid relations. We conjecture that the structure of the model is protected by an emergent symmetry analogous to fermion parity. 1) NSF Grant DMR-1341822 2) Institute for Quantum Information and Matter, an NSF physics frontier center with support from the Moore Foundation. 3) NSERC-PGSD.

  16. A 1D analysis of two high order MOC methods

    SciTech Connect

    Everson, M. S.; Forget, B.

    2012-07-01

    The work presented here provides two different methods for evaluating angular fluxes along long characteristics. One is based off a projection of the 1D transport equation onto a complete set of Legendre polynomials, while the other uses the 1D integral transport equation to evaluate the angular flux values at specific points along each track passing through a cell. The Moment Long Characteristic (M-LC) method is shown to provide 2(P+1) spatial convergence and significant gains in accuracy with the addition of only a few spatial degrees of freedom. The M-LC method, though, is shown to be ill-conditioned at very high order and for optically thin geometries. The Point Long Characteristic (P-LC) method, while less accurate, significantly improves stability to problems with optically thin cells. The P-LC method is also more flexible, allowing for extra angular flux evaluations along a given track to give a more accurate representation of the shape along each track. This is at the expense of increasing the degrees of freedom of the system, though, and requires an increase in memory storage. This work concludes that both may be used simultaneously within the same geometry to provide the best mix of accuracy and stability possible. (authors)

  17. Engineered atom-light interactions in 1D photonic crystals

    NASA Astrophysics Data System (ADS)

    Martin, Michael J.; Hung, Chen-Lung; Yu, Su-Peng; Goban, Akihisa; Muniz, Juan A.; Hood, Jonathan D.; Norte, Richard; McClung, Andrew C.; Meenehan, Sean M.; Cohen, Justin D.; Lee, Jae Hoon; Peng, Lucas; Painter, Oskar; Kimble, H. Jeff

    2014-05-01

    Nano- and microscale optical systems offer efficient and scalable quantum interfaces through enhanced atom-field coupling in both resonators and continuous waveguides. Beyond these conventional topologies, new opportunities emerge from the integration of ultracold atomic systems with nanoscale photonic crystals. One-dimensional photonic crystal waveguides can be engineered for both stable trapping configurations and strong atom-photon interactions, enabling novel cavity QED and quantum many-body systems, as well as distributed quantum networks. We present the experimental realization of such a nanophotonic quantum interface based on a nanoscale photonic crystal waveguide, demonstrating a fractional waveguide coupling of Γ1 D /Γ' of 0 . 32 +/- 0 . 08 , where Γ1 D (Γ') is the atomic emission rate into the guided (all other) mode(s). We also discuss progress towards intra-waveguide trapping of ultracold Cs. This work was supported by the IQIM, an NSF Physics Frontiers Center with support from the Moore Foundation, the DARPA ORCHID program, the AFOSR QuMPASS MURI, the DoD NSSEFF program, NSF, and the Kavli Nanoscience Institute (KNI) at Caltech.

  18. Intense visible upconversion and energy transfer in Ho3+/Yb3+ codoped tellurite glasses for potential fiber laser

    NASA Astrophysics Data System (ADS)

    Peng, Shengxi; Wu, Libo; Wang, Bo; Yang, Fengjing; Qi, Yawei; Zhou, Yaxun

    2015-03-01

    New Ho3+/Yb3+ codoped tellurite glasses (TeO2-Bi2O3-ZnO-Na2O) prepared by melt-quenching technique were investigated to realize visible-band upconversion emissions applied for compact fiber lasers. The absorption spectra, upconversion emission spectra, differential scanning calorimetry (DSC) curves, X-ray diffraction (XRD) and Raman spectra were measured to characterize the spectroscopic properties of Ho3+, thermal stability and structural nature of glass hosts. Under the excitation of 980 nm laser diode (LD), the intense green (∼543 nm) and red (∼657 nm) upconversion emissions corresponding to 5F4(5S2) → 5I8 and 5F5 → 5I8 transitions of Ho3+ respectively are simultaneously observed. The power dependence study of upconversion intensities on excited pump power revealed that the Ho3+ population at 5F4(5S2) and 5F5 levels was originated from two-photon absorption process based on the energy transfer from Yb3+ to Ho3+. The energy transfer mechanism from Yb3+ to Ho3+ was investigated and relevant micro-parameters (energy transfer coefficient and critical radius) and phonon contribution ratio were presented. With the increase of Yb3+ doped concentration, both the green and red upconversion intensities enhanced greatly, meanwhile the thermal stability of glass hosts, characterized by the three characteristic temperatures, also got a slight improvement. Furthermore, the glass structure was briefly analyzed with the calculated Judd-Ofelt intensity parameters, the measured Raman spectra and XRD curves. The present results indicate that the new synthesized Ho3+/Yb3+ codoped tellurite glass with intense green and red upconversion emissions is a promising medium applied for the visible-band fiber lasers.

  19. Photon upconversion sensitized nanoprobes for sensing and imaging of pH

    NASA Astrophysics Data System (ADS)

    Arppe, Riikka; Näreoja, Tuomas; Nylund, Sami; Mattsson, Leena; Koho, Sami; Rosenholm, Jessica M.; Soukka, Tero; Schäferling, Michael

    2014-05-01

    Acidic pH inside cells indicates cellular dysfunctions such as cancer. Therefore, the development of optical pH sensors for measuring and imaging intracellular pH is a demanding challenge. The available pH-sensitive probes are vulnerable to e.g. photobleaching or autofluorescence background in biological materials. Our approach circumvents these problems due to near infrared excitation and upconversion photoluminescence. We introduce a nanosensor based on upconversion resonance energy transfer (UC-RET) between an upconverting nanoparticle (UCNP) and a fluorogenic pH-dependent dye pHrodo™ Red that was covalently bound to the aminosilane surface of the nanoparticles. The sensitized fluorescence of the pHrodo™ Red dye increases strongly with decreasing pH. By referencing the pH-dependent emission of pHrodo™ Red with the pH-insensitive upconversion photoluminescence of the UCNP, we developed a pH-sensor which exhibits a dynamic range from pH 7.2 to 2.5. The applicability of the introduced pH nanosensor for pH imaging was demonstrated by imaging the two emission wavelengths of the nanoprobe in living HeLa cells with a confocal fluorescence microscope upon 980 nm excitation. This demonstrates that the presented pH-nanoprobe can be used as an intracellular pH-sensor due to the unique features of UCNPs: excitation with deeply penetrating near-infrared light, high photostability, lack of autofluorescence and biocompatibility due to an aminosilane coating.Acidic pH inside cells indicates cellular dysfunctions such as cancer. Therefore, the development of optical pH sensors for measuring and imaging intracellular pH is a demanding challenge. The available pH-sensitive probes are vulnerable to e.g. photobleaching or autofluorescence background in biological materials. Our approach circumvents these problems due to near infrared excitation and upconversion photoluminescence. We introduce a nanosensor based on upconversion resonance energy transfer (UC-RET) between an

  20. Detection of early primary colorectal cancer with upconversion luminescent NP-based molecular probes

    NASA Astrophysics Data System (ADS)

    Liu, Chunyan; Qi, Yifei; Qiao, Ruirui; Hou, Yi; Chan, Kaying; Li, Ziqian; Huang, Jiayi; Jing, Lihong; Du, Jun; Gao, Mingyuan

    2016-06-01

    Early detection and diagnosis of cancers is extremely beneficial for improving the survival rate of cancer patients and molecular imaging techniques are believed to be relevant for offering clinical solutions. Towards early cancer detection, we developed a primary animal colorectal cancer model and constructed a tumor-specific imaging probe by using biocompatible NaGdF4:Yb,Er@NaGdF4 upconversion luminescent NPs for establishing a sensitive early tumor imaging method. The primary animal tumor model, which can better mimic the human colorectal cancer, was built upon continual administration of 1,2-dimethylhydrazine in Kunming mice and the tumor development was carefully monitored through histopathological and immunohistochemical analyses to reveal the pathophysiological processes and molecular features of the cancer microenvironment. The upconversion imaging probe was constructed through covalent coupling of PEGylated core-shell NPs with folic acid whose receptor is highly expressed in the primary tumors. Upon 980 nm laser excitation, the primary colorectal tumors in the complex abdominal environment were sensitively imaged owing to the ultralow background of the upconversion luminescence and the high tumor-targeting specificity of the nanoprobe. We believe that the current studies provide a highly effective and potential approach for early colorectal cancer diagnosis and tumor surgical navigation.Early detection and diagnosis of cancers is extremely beneficial for improving the survival rate of cancer patients and molecular imaging techniques are believed to be relevant for offering clinical solutions. Towards early cancer detection, we developed a primary animal colorectal cancer model and constructed a tumor-specific imaging probe by using biocompatible NaGdF4:Yb,Er@NaGdF4 upconversion luminescent NPs for establishing a sensitive early tumor imaging method. The primary animal tumor model, which can better mimic the human colorectal cancer, was built upon continual

  1. Axion string dynamics I: 2+1D

    NASA Astrophysics Data System (ADS)

    Fleury, Leesa M.; Moore, Guy D.

    2016-05-01

    If the axion exists and if the initial axion field value is uncorrelated at causally disconnected points, then it should be possible to predict the efficiency of cosmological axion production, relating the axionic dark matter density to the axion mass. The main obstacle to making this prediction is correctly treating the axion string cores. We develop a new algorithm for treating the axionic string cores correctly in 2+1 dimensions. When the axionic string cores are given their full physical string tension, axion production is about twice as efficient as in previous simulations. We argue that the string network in 2+1 dimensions should behave very differently than in 3+1 dimensions, so this result cannot be simply carried over to the physical case. We outline how to extend our method to 3+1D axion string dynamics.

  2. 1D-transport properties of single superconducting lead nanowires

    NASA Astrophysics Data System (ADS)

    Michotte, S.; Mátéfi-Tempfli, S.; Piraux, L.

    2003-09-01

    We report on the transport properties of single superconducting lead nanowires grown by an electrodeposition technique, embedded in a nanoporous track-etched polymer membrane. The nanowires are granular, have uniform diameter of ∼40 nm and a very large aspect ratio (∼500). The diameter of the nanowire is small enough to ensure a 1D superconducting regime in a wide temperature range below Tc. The non-zero resistance in the superconducting state and its variation caused by fluctuations of the superconducting order parameter were measured versus temperature, magnetic field, and applied DC current (or voltage). The current induced breakdowns in the V- I characteristics may be explained by the formation of phase slip centers. Moreover, DC voltage driven measurements reveal the existence of a new S-shape behavior near the formation of these phase slip centers.

  3. Microlens Masses from 1-D Parallaxes and Heliocentric Proper Motions

    NASA Astrophysics Data System (ADS)

    Gould, Andrew

    2014-12-01

    One-dimensional (1-D) microlens parallaxes can be combined with heliocentric lens-source relative proper motion measurements to derive the lens mass and distance, as suggested by Ghosh et al. (2004). Here I present the first mathematical anlysis of this procedure, which I show can be represented as a quadratic equation. Hence, it is formally subject to a two-fold degeneracy. I show that this degeneracy can be broken in many cases using the relatively crude 2-D parallax information that is often available for microlensing events. I also develop an explicit formula for the region of parameter space where it is more difficult to break this degeneracy. Although no mass/distance measurements have yet been made using this technique, it is likely to become quite common over the next decade.

  4. Quadratic Finite Element Method for 1D Deterministic Transport

    SciTech Connect

    Tolar, Jr., D R; Ferguson, J M

    2004-01-06

    In the discrete ordinates, or SN, numerical solution of the transport equation, both the spatial ({und r}) and angular ({und {Omega}}) dependences on the angular flux {psi}{und r},{und {Omega}}are modeled discretely. While significant effort has been devoted toward improving the spatial discretization of the angular flux, we focus on improving the angular discretization of {psi}{und r},{und {Omega}}. Specifically, we employ a Petrov-Galerkin quadratic finite element approximation for the differencing of the angular variable ({mu}) in developing the one-dimensional (1D) spherical geometry S{sub N} equations. We develop an algorithm that shows faster convergence with angular resolution than conventional S{sub N} algorithms.

  5. Effective theory of black holes in the 1/D expansion

    NASA Astrophysics Data System (ADS)

    Emparan, Roberto; Shiromizu, Tetsuya; Suzuki, Ryotaku; Tanabe, Kentaro; Tanaka, Takahiro

    2015-06-01

    The gravitational field of a black hole is strongly localized near its horizon when the number of dimensions D is very large. In this limit, we can effectively replace the black hole with a surface in a background geometry (e.g. Minkowski or Anti-deSitter space). The Einstein equations determine the effective equations that this `black hole surface' (or membrane) must satisfy. We obtain them up to next-to-leading order in 1/ D for static black holes of the Einstein-(A)dS theory. To leading order, and also to next order in Minkowski backgrounds, the equations of the effective theory are the same as soap-film equations, possibly up to a redshift factor. In particular, the Schwarzschild black hole is recovered as a spherical soap bubble. Less trivially, we find solutions for `black droplets', i.e. black holes localized at the boundary of AdS, and for non-uniform black strings.

  6. Connected components of irreducible maps and 1D quantum phases

    NASA Astrophysics Data System (ADS)

    Szehr, Oleg; Wolf, Michael M.

    2016-08-01

    We investigate elementary topological properties of sets of completely positive (CP) maps that arise in quantum Perron-Frobenius theory. We prove that the set of primitive CP maps of fixed Kraus rank is path-connected and we provide a complete classification of the connected components of irreducible CP maps at given Kraus rank and fixed peripheral spectrum in terms of a multiplicity index. These findings are then applied to analyse 1D quantum phases by studying equivalence classes of translational invariant matrix product states that correspond to the connected components of the respective CP maps. Our results extend the previously obtained picture in that they do not require blocking of physical sites, they lead to analytic paths, and they allow us to decompose into ergodic components and to study the breaking of translational symmetry.

  7. Glycolipid antigen processing for presentation by CD1d molecules.

    PubMed

    Prigozy, T I; Naidenko, O; Qasba, P; Elewaut, D; Brossay, L; Khurana, A; Natori, T; Koezuka, Y; Kulkarni, A; Kronenberg, M

    2001-01-26

    The requirement for processing glycolipid antigens in T cell recognition was examined with mouse CD1d-mediated responses to glycosphingolipids (GSLs). Although some disaccharide GSL antigens can be recognized without processing, the responses to three other antigens, including the disaccharide GSL Gal(alpha1-->2)GalCer (Gal, galactose; GalCer, galactosylceramide), required removal of the terminal sugars to permit interaction with the T cell receptor. A lysosomal enzyme, alpha-galactosidase A, was responsible for the processing of Gal(alpha1-->2)GalCer to generate the antigenic monosaccharide epitope. These data demonstrate a carbohydrate antigen processing system analogous to that used for peptides and an ability of T cells to recognize processed fragments of complex glycolipids.

  8. Investigation of upconversion and near infrared emission properties in CeO₂: Er³⁺, Yb³⁺ inverse opals.

    PubMed

    Wu, Hangjun; Yang, Zhengwen; Liao, Jiayan; Lai, Shenfeng; Qiu, Jianbei; Song, Zhiguo; Yang, Yong; Zhou, Dacheng; Yin, Zhaoyi

    2013-09-23

    The upconversion emission of rare earth ions can be modified in photonic crystals, however, the influence of upconversion emission modification of rare earths on near infrared emission has not been investigated yet in the photonic crystals. In the paper, CeO₂: Er³⁺, Yb³⁺ inverse opals with the photonic band gaps at 545, 680 and 450 nm were prepared by polystyrene colloidal crystal templates. The upconversion and the near infrared emission properties of Er³⁺ ions were systematically investigated in the CeO₂: Er³⁺, Yb³⁺ inverse opals. Comparing with the reference sample, significant suppression of both the green and red upconversion luminescence of Er³⁺ ions were observed in the inverse opals. It is interesting that the infrared emission located at 1,560 nm was enhanced due to inhibition of upconversion emission in the inverse opals. Additionally, mechanism of upconversion emission of the inverse opal was discussed. The photon avalanche upconversion process is observed. PMID:24104110

  9. Investigation of upconversion and near infrared emission properties in CeO₂: Er³⁺, Yb³⁺ inverse opals.

    PubMed

    Wu, Hangjun; Yang, Zhengwen; Liao, Jiayan; Lai, Shenfeng; Qiu, Jianbei; Song, Zhiguo; Yang, Yong; Zhou, Dacheng; Yin, Zhaoyi

    2013-09-23

    The upconversion emission of rare earth ions can be modified in photonic crystals, however, the influence of upconversion emission modification of rare earths on near infrared emission has not been investigated yet in the photonic crystals. In the paper, CeO₂: Er³⁺, Yb³⁺ inverse opals with the photonic band gaps at 545, 680 and 450 nm were prepared by polystyrene colloidal crystal templates. The upconversion and the near infrared emission properties of Er³⁺ ions were systematically investigated in the CeO₂: Er³⁺, Yb³⁺ inverse opals. Comparing with the reference sample, significant suppression of both the green and red upconversion luminescence of Er³⁺ ions were observed in the inverse opals. It is interesting that the infrared emission located at 1,560 nm was enhanced due to inhibition of upconversion emission in the inverse opals. Additionally, mechanism of upconversion emission of the inverse opal was discussed. The photon avalanche upconversion process is observed.

  10. Thiazole derivative-modified upconversion nanoparticles for Hg2+ detection in living cells

    NASA Astrophysics Data System (ADS)

    Gu, Bin; Zhou, Yi; Zhang, Xiao; Liu, Xiaowang; Zhang, Yuhai; Marks, Robert; Zhang, Hua; Liu, Xiaogang; Zhang, Qichun

    2015-12-01

    Mercury ion (Hg2+) is an extremely toxic ion, which will accumulate in human bodies and cause severe nervous system damage. Therefore, the sensitive and efficient monitoring of Hg2+ in human bodies is of great importance. Upconversion nanoparticle (UCNPs) based nano probes exhibit no autofluorescence, deep penetration depth and chemical stability in biological samples, as well as a large anti-stokes shift. In this study, we have developed thiazole-derivative-functionalized UCNPs, and employed an upconversion emission intensity ratio of 540 nm to 803 nm (I540/I803) as a ratiometric signal to detect Hg2+ in living cells showing excellent photo stability and high selectivity. Our nano probe was characterized using transmission electron microscopy (TEM) and powder X-ray diffraction (PXRD). The low cytotoxicity of our probe was confirmed by an MTT assay and the UCL test in HeLa cells was carried out by confocal microscopy. Our results demonstrated that organic-dye-functionalized UCNPs should be a good strategy for detecting toxic metal ions when studying cellular biosystems.Mercury ion (Hg2+) is an extremely toxic ion, which will accumulate in human bodies and cause severe nervous system damage. Therefore, the sensitive and efficient monitoring of Hg2+ in human bodies is of great importance. Upconversion nanoparticle (UCNPs) based nano probes exhibit no autofluorescence, deep penetration depth and chemical stability in biological samples, as well as a large anti-stokes shift. In this study, we have developed thiazole-derivative-functionalized UCNPs, and employed an upconversion emission intensity ratio of 540 nm to 803 nm (I540/I803) as a ratiometric signal to detect Hg2+ in living cells showing excellent photo stability and high selectivity. Our nano probe was characterized using transmission electron microscopy (TEM) and powder X-ray diffraction (PXRD). The low cytotoxicity of our probe was confirmed by an MTT assay and the UCL test in HeLa cells was carried out by

  11. Tailoring dye-sensitized upconversion nanoparticle excitation bands towards excitation wavelength selective imaging

    SciTech Connect

    Wu, Xiang; Lee, Hyungseok; Bilsel, Osman; Zhang, Yuanwei; Li, Zhanjun; Chen, Teresa; Liu, Yi; Duan, Chunying; Shen, Jie; Punjabi, Amol; Han, Gang

    2015-01-01

    One of the key roadblocks in UCNP development is its extremely limited choices of excitation wavelengths. We report a generic design to program UCNPs to possess highly tunable dye characteristic excitation bands. Using such distinctive properties, we were able to develop a new excitation wavelength selective security imaging. Finally, this work unleashed the greater freedom of the excitation wavelengths of the upconversion nanoparticles and we believe it is a game-changer in the field and this method will enable numerous applications that are currently limited by existing UCNPs.

  12. High pressure polymorphs and amorphization of upconversion host material NaY(WO4)2

    NASA Astrophysics Data System (ADS)

    Hong, Fang; Yue, Binbin; Cheng, Zhenxiang; Kunz, Martin; Chen, Bin; Mao, Ho-Kwang

    2016-07-01

    The pressure effect on the structural change of upconversion host material NaY(WO4)2 was studied by using in-situ synchrotron X-ray diffraction. A transition from the initial scheelite phase to the M-fergusonite phase occurs near 10 GPa, and another phase transition is found near 27.5 GPa, which could be an isostructural transition without symmetry change. The sample becomes amorphous when the pressure is fully released from high pressure. This work demonstrates the possibility of synthesizing various polymorph structures for non-linear optical applications with a high pressure, chemical doping, or strained thin-film nanostructure process.

  13. Enhanced Red Upconversion Luminescence in Yb-Er Codoped NaYF4 Nanocrystals.

    PubMed

    Song, Weiye; Bi, Xueqing; Guo, Xingyuan; Liu, Shushen; Qin, Weiping

    2016-04-01

    In this work the effects of NaYF4:Yb,Er (NYE) structure on the enhanced red upconversion luminescence (UC) was investigated. α-NYE nanocrystals (NCs) and β-NYE NCs were fabricated by a high temperature decomposition reaction method. The prepared NCs were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and photoluminescence (PL) spectroscopy. The results show that the red UC luminescence of α-NYE NCs is significantly enhanced compared with that of β-NYE. Furthermore, a possible energy transfer mechanism was proposed on the basis of our experimental results. PMID:27451746

  14. Tailoring Dye-sensitized Upconversion Nanoparticles Excitation Bands towards Excitation Wavelength Selective Imaging

    PubMed Central

    Wu, Xiang; Lee, Hyungseok; Bilsel, Osman; Zhang, Yuanwei; Li, Zhanjun; Chen, Teresa; Liu, Yi; Duan, Chunying; Shen, Jie; Punjabi, Amol; Han, Gang

    2015-01-01

    One of key roadblocks in UCNP development is its extremely limited choices of excitation wavelengths. We report a generic design to program UCNPs to possess highly tunable dye characteristic excitation bands. Using such distinctive properties, we were able to develop a new excitation wavelength selective security imaging. This work unleashed the greater freedom of the excitation wavelengths of the upconversion nanoparticles and we believe it is a game-changer in the field and this method will enable numerous applications that are currently limited by existing UCNPs. PMID:26499208

  15. Dye-Sensitized Solar Cell with Integrated Triplet-Triplet Annihilation Upconversion System.

    PubMed

    Nattestad, Andrew; Cheng, Yuen Yap; MacQueen, Rowan W; Schulze, Tim F; Thompson, Fletcher W; Mozer, Attila J; Fückel, Burkhard; Khoury, Tony; Crossley, Maxwell J; Lips, Klaus; Wallace, Gordon G; Schmidt, Timothy W

    2013-06-20

    Photon upconversion (UC) by triplet-triplet annihilation (TTA-UC) is employed in order to enhance the response of solar cells to sub-bandgap light. Here, we present the first report of an integrated photovoltaic device, combining a dye-sensitized solar cell (DSC) and TTA-UC system. The integrated device displays enhanced current under sub-bandgap illumination, resulting in a figure of merit (FoM) under low concentration (3 suns), which is competitive with the best values recorded to date for nonintegrated systems. Thus, we demonstrate both the compatibility of DSC and TTA-UC and a viable method for device integration.

  16. Roles of TBC1D1 and TBC1D4 in insulin- and exercise-stimulated glucose transport of skeletal muscle

    PubMed Central

    Cartee, Gregory D.

    2014-01-01

    This review focuses on two paralogue Rab GTPase activating proteins known as TBC1D1 Tre-2/BUB2/cdc 1 domain family (TBC1D) 1 and TBC1D4 (also called Akt Substrate of 160 kDa, AS160) and their roles in controlling skeletal muscle glucose transport in response to the independent and combined effects of insulin and exercise. Convincing evidence implicates Akt2-dependent TBC1D4 phosphorylation on T642 as a key part of the mechanism for insulin-stimulated glucose uptake by skeletal muscle. TBC1D1 phosphorylation on several insulin-responsive sites (including T596, a site corresponding to T642 in TBC1D4) does not appear to be essential for in vivo insulin-stimulated glucose uptake by skeletal muscle. In vivo exercise or ex vivo contraction of muscle result in greater TBC1D1 phosphorylation on S237 that is likely to be secondary to increased AMP-activated protein kinase activity and potentially important for contraction-stimulated glucose uptake. Several studies that evaluated both normal and insulin-resistant skeletal muscle stimulated with a physiological insulin concentration after a single exercise session found that greater post-exercise insulin-stimulated glucose uptake was accompanied by greater TBC1D4 phosphorylation on several sites. In contrast, enhanced post-exercise insulin sensitivity was not accompanied by greater insulin-stimulated TBC1D1 phosphorylation. The mechanism for greater TBC1D4 phosphorylation in insulin-stimulated muscles after acute exercise is uncertain, and a causal link between enhanced TBC1D4 phosphorylation and increased post-exercise insulin sensitivity has yet to be established. In summary, TBC1D1 and TBC1D4 have important, but distinct roles in regulating muscle glucose transport in response to insulin and exercise. PMID:25280670

  17. Upconversion, size analysis, and fiber filling of NaYF4: Ho3+, Yb3+ crystals and nanocolloids

    NASA Astrophysics Data System (ADS)

    Patel, Darayas; Lewis, Ashley; Wright, Donald; Velentine, Maucus; Lewis, Danielle; Valentine, Ruben; Sarkisov, Sergey

    2014-03-01

    Nano-colloids and nano-crystals doped with ions of rare-earth elements have recently attracted a lot of attention in the scientific community. This attention is due to unique physical, chemical and optical properties attributed to nanometer size of the particles. They have great potential of being used in applications spanning from new types of lasers, especially blue and UV ones, phosphorous display monitors, optical communications, and fluorescence imaging. In this paper we investigate the near-infrared upconversion luminescence in bulk crystals and nanocolloid filled photonic crystal fiber with ytterbium and holmium co-doped NaYF4 phosphor. The phosphor is prepared by using simple co-precipitation synthetic method. The initially prepared phosphor has very week upconversion fluorescence. The fluorescence significantly increased after the phosphor was annealed at a temperature of 600 °C. Nanocolloids of this phosphor were obtained using 1-propanol as solvent and they were utilized as laser filling medium in photonic crystal fibers. Under 980 nm diode laser excitation very strong upconversion signals were obtained for ytterbium and holmium co-doped phosphor at 541 nm, 646 nm and 751 nm. Pump power emissions, laser ablation and size analysis of the particles was conducted to understand the upconversion mechanisms. The particle sizes of the nanocolloids were analyzed using Atomic Force Microscope and Malvern Zetasizer instrument. The reported nanocolloids are good candidates for fluorescent biosensing applications and also as a new laser filling medium in fiber laser.

  18. Triplet-triplet annihilation upconversion based nanocapsules for bioimaging under excitation by red and deep-red light.

    PubMed

    Wohnhaas, Christian; Mailänder, Volker; Dröge, Melanie; Filatov, Mikhail A; Busko, Dmitry; Avlasevich, Yuri; Baluschev, Stanislav; Miteva, Tzenka; Landfester, Katharina; Turshatov, Andrey

    2013-10-01

    Non-toxic and biocompatible triplet-triplet annihilation upconversion based nanocapsules (size less than 225 nm) were successfully fabricated by the combination of miniemulsion and solvent evaporation techniques. A first type of nanocapsules displays an upconversion spectrum characterized by the maximum of emission at λmax = 550 nm under illumination by red light, λexc = 633 nm. The second type of nanocapsules fluoresces at λmax = 555 nm when excited with deep-red light, λexc = 708 nm. Conventional confocal laser scanning microscopy (CLSM) and flow cytometry were applied to determine uptake and toxicity of the nanocapsules for various (mesenchymal stem and HeLa) cells. Red light (λexc = 633 nm) with extremely low optical power (less than 0.3 μW) or deep-red light (λexc = 708 nm) was used in CLSM experiments to generate green upconversion fluorescence. The cell images obtained with upconversion excitation demonstrate order of magnitude better signal to background ratio than the cell images obtained with direct excitation of the same fluorescence marker.

  19. Synthesis of NaYF4 and NaLuF4 Based Upconversion Nanocrystals and Comparison of Their Properties.

    PubMed

    Ouyang, Juan; Yin, Dongguang; Song, Kailin; Wang, Chengcheng; Liu, Bing; Wu, Minghong

    2015-04-01

    In this study, four kinds of upconversion nanocrystals (UCNs) have been successfully synthesized by a facile solvothermal method. The morphology, crystalline phase, composition, grain size, upconversion luminescence and cell image of the UCNs were investigated. The properties of the NaLuF4-based UCNs were compared with the counterparts of NaYF4-based UCNs. It is found that the NaLuF4-based UCNs are apt to form hexagonal phase structures, while NaYF4-based UCNs of NaYF4:Yb, Er and NaYF4:Gd, Yb, Er are cubic and hexagonal phases respectively. The upconversion emission intensities of the NaLuF4-based UCNs are higher than that of NaYF4-based UCNs, and Gd3+ presented UCNs are higher than that of Gd3+ absented UCNs. The bioimaging application of NaLuF4:Gd, Yb, Er shows that bright upconversion luminescence can be observed when UCNs-labeled HeLa cells are excited with 980 nm light. PMID:26353495

  20. Upconversion emission in antimony-germanate double-clad optical fiber co-doped with Yb3+/Tm3+ ions

    NASA Astrophysics Data System (ADS)

    Kochanowicz, M.; Dorosz, D.; Zmojda, J.; Miluski, P.; Dorosz, J.; Pisarska, J.; Pisarski, W. A.

    2015-03-01

    In the paper upconversion luminescence properties in Yb3+/Tm3+ co-doped antimony-germanate glass and double-clad optical fiber were studied. The concentration of lanthanides, which has shown the highest upconversion emission intensity at 478 nm (1G4 → 3H6) and 650 nm (1G4 → 3F4), is 1Yb2O3/0.1Tm2O3 (mol%) as a result of exciting with a laser diode (976 nm). The lifetime of 2F5/2 (Yb3+) level decreases from 781 μs to 71 μs in the presence of Tm3+ 0.1-0.75 mol% respectively. Luminescence decay curve of glass co-doped with 1Yb2O3/0.75Tm2O3 suggests donor-donor fast migration followed by Tm3+ → Yb3+ energy transfer. Glass characterized by highest intensity of upconversion luminescence (1Yb2O3/0.1Tm2O3 mol%) was used as core of double-clad optical fiber made by modified rod-in-tube method. Mechanisms influencing differences in upconversion amplified spontaneous emission of the fabricated optical fiber and bulk glass were discussed. Reabsorption of the amplified spontaneous emission signal along the fibre resulting from Tm3+:3H6 → 1G4, transition was observed.

  1. Fundamental aspects and design of FM upconversion receiver front-end with on-chip SAW filters

    NASA Astrophysics Data System (ADS)

    Vanzeijl, Paulus Thomas Maria

    The characteristics of FM (Frequency Modulation) receivers, including tuned radio frequency and single conversion receivers, are described. The modeling of SAW (Surface Acoustic Wave) delay lines, SAW transversal filters and the behavior of SAW resonators and SAW resonator filters are discussed. The design of the FM upconversion receiver front end is described and a new class of balanced dual loop amplifiers is discussed.

  2. Synthesis of NaYF4 and NaLuF4 Based Upconversion Nanocrystals and Comparison of Their Properties.

    PubMed

    Ouyang, Juan; Yin, Dongguang; Song, Kailin; Wang, Chengcheng; Liu, Bing; Wu, Minghong

    2015-04-01

    In this study, four kinds of upconversion nanocrystals (UCNs) have been successfully synthesized by a facile solvothermal method. The morphology, crystalline phase, composition, grain size, upconversion luminescence and cell image of the UCNs were investigated. The properties of the NaLuF4-based UCNs were compared with the counterparts of NaYF4-based UCNs. It is found that the NaLuF4-based UCNs are apt to form hexagonal phase structures, while NaYF4-based UCNs of NaYF4:Yb, Er and NaYF4:Gd, Yb, Er are cubic and hexagonal phases respectively. The upconversion emission intensities of the NaLuF4-based UCNs are higher than that of NaYF4-based UCNs, and Gd3+ presented UCNs are higher than that of Gd3+ absented UCNs. The bioimaging application of NaLuF4:Gd, Yb, Er shows that bright upconversion luminescence can be observed when UCNs-labeled HeLa cells are excited with 980 nm light.

  3. Intense ultraviolet upconversion emission from water-dispersed colloidal YF3:Yb3+/Tm3+ rhombic nanodisks.

    PubMed

    Qiu, Hailong; Chen, Guanying; Fan, Rongwei; Yang, Liming; Liu, Cheng; Hao, Shuwei; Sailor, Michael J; Ågren, Hans; Yang, Chunhui; Prasad, Paras N

    2014-01-21

    Intense ultraviolet upconversion emission has been observed in water-dispersed uniform rhombic nanodisks (side length of ~14 nm and thickness of ~2.5 nm) of YF3 co-doped with Yb(3+) sensitizer and Tm(3+) activator ions, when excited at ~980 nm.

  4. 1D X-ray Beam Compressing Monochromators

    SciTech Connect

    Korytar, D.; Dobrocka, E.; Konopka, P.; Zaprazny, Z.; Ferrari, C.; Mikulik, P.; Vagovic, P.; Ac, V.; Erko, A.; Abrosimov, N.

    2010-04-06

    A total beam compression of 5 and 10 corresponding to the asymmetry angles of 9 deg. and 12 deg. is achieved with V-5 and V-10 monochromators, respectively, in standard single crystal pure germanium (220) X-ray beam compressing (V-shaped) monochromators for CuKalpha{sub 1} radiation. A higher 1D compression of X-ray beam is possible using larger angles of asymmetry, however it is achieved at the expense of the total intensity, which is decreased due to the refraction effect. To increase the monochromator intensity, several ways are considered both theoretically and experimentally. Linearly graded germanium rich Ge{sub x}Si{sub (1-x)} single crystal was used to prepare a V-21 single crystal monochromator with 15 deg. asymmetry angles (compression factor of 21). Its temperature gradient version is discussed for CuKalpha{sub 1} radiation. X-ray diffraction measurements on the graded GeSi monochromator showed more than 3-times higher intensity at the output compared with that of a pure Ge monochromator.

  5. 1-D Numerical Analysis of RBCC Engine Performance

    NASA Technical Reports Server (NTRS)

    Han, Samuel S.

    1998-01-01

    An RBCC engine combines air breathing and rocket engines into a single engine to increase the specific impulse over an entire flight trajectory. Considerable research pertaining to RBCC propulsion was performed during the 1960's and these engines were revisited recently as a candidate propulsion system for either a single-stage-to-orbit (SSTO) or two-stage-to-orbit (TSTO) launch vehicle. There are a variety of RBCC configurations that had been evaluated and new designs are currently under development. However, the basic configuration of all RBCC systems is built around the ejector scramjet engine originally developed for the hypersonic airplane. In this configuration, a rocket engine plays as an ejector in the air-augmented initial acceleration mode, as a fuel injector in scramjet mode and the rocket in all rocket mode for orbital insertion. Computational fluid dynamics (CFD) is a useful tool for the analysis of complex transport processes in various components in RBCC propulsion systems. The objective of the present research was to develop a transient 1-D numerical model that could be used to predict flow behavior throughout a generic RBCC engine following a flight path.

  6. Dynamic decoupling in the presence of 1D random walk

    NASA Astrophysics Data System (ADS)

    Chakrabarti, Arnab; Chakraborty, Ipsita; Bhattacharyya, Rangeet

    2016-05-01

    In the recent past, many dynamic decoupling sequences have been proposed for the suppression of decoherence of spins connected to thermal baths of various natures. Dynamic decoupling schemes for suppressing decoherence due to Gaussian diffusion have also been developed. In this work, we study the relative performances of dynamic decoupling schemes in the presence of a non-stationary Gaussian noise such as a 1D random walk. Frequency domain analysis is not suitable to determine the performances of various dynamic decoupling schemes in suppressing decoherence due to such a process. Thus, in this work, we follow a time domain calculation to arrive at the following conclusions: in the presence of such a noise, we show that (i) the traditional Carr–Purcell–Meiboom–Gill (CPMG) sequence outperforms Uhrig’s dynamic decoupling scheme, (ii) CPMG remains the optimal sequence for suppression of decoherence due to random walk in the presence of an external field gradient. Later, the theoretical predictions are experimentally verified by using nuclear magnetic resonance spectroscopy on spin 1/2 particles diffusing in a liquid medium.

  7. Control and imaging of O(1D2) precession

    NASA Astrophysics Data System (ADS)

    Wu, Shiou-Min; Radenovic, Dragana Č.; van der Zande, Wim J.; Groenenboom, Gerrit C.; Parker, David H.; Vallance, Claire; Zare, Richard N.

    2011-01-01

    Larmor precession of a quantum mechanical angular momentum vector about an applied magnetic field forms the basis for a range of magnetic resonance techniques, including nuclear magnetic resonance spectroscopy and magnetic resonance imaging. We have used a polarized laser pump-probe scheme with velocity-map imaging detection to visualize, for the first time, the precessional motion of a quantum mechanical angular momentum vector. Photodissociation of O2 at 157 nm provides a clean source of fast-moving O(1D2) atoms, with their electronic angular momentum vector strongly aligned perpendicular to the recoil direction. In the presence of an external magnetic field, the distribution of atomic angular momenta precesses about the field direction, and polarization-sensitive images of the atomic scattering distribution recorded as a function of field strength yield ‘time-lapse-photography’ style movies of the precessional motion. We present movies recorded in various experimental geometries, and discuss potential consequences and applications in atmospheric chemistry and reaction dynamics.

  8. Quantifying Aflatoxin B1 in peanut oil using fabricating fluorescence probes based on upconversion nanoparticles.

    PubMed

    Sun, Cuicui; Li, Huanhuan; Koidis, Anastasios; Chen, Quansheng

    2016-08-01

    Rare earth doped upconversion nanoparticles convert near-infrared excitation light into visible emission light. Compared to organic fluorophores and semiconducting nanoparticles, upconversion nanoparticles (UCNPs) offer high photochemical stability, sharp emission bandwidths, and large anti-Stokes shifts. Along with the significant light penetration depth and the absence of autofluorescence in biological samples under infrared excitation, these UCNPs have attracted more and more attention on toxin detection and biological labelling. Herein, the fluorescence probe based on UCNPs was developed for quantifying Aflatoxin B1 (AFB1) in peanut oil. Based on a specific immunity format, the detection limit for AFB1 under optimal conditions was obtained as low as 0.2ng·ml(-1), and in the effective detection range 0.2 to 100ng·ml(-1), good relationship between fluorescence intensity and AFB1 concentration was achieved under the linear ratios up to 0.90. Moreover, to check the feasibility of these probes on AFB1 measurements in peanut oil, recovery tests have been carried out. A good accuracy rating (93.8%) was obtained in this study. Results showed that the nanoparticles can be successfully applied for sensing AFB1 in peanut oil. PMID:27124091

  9. Q-Band Millimeter Wave Imaging in the Far-Field Enabled by Optical Upconversion Methodology

    NASA Astrophysics Data System (ADS)

    Samluk, Jesse P.; Schuetz, Christopher A.; Dillon, Thomas; Stein, E. Lee; Robbins, Andrew; Mackrides, Daniel G.; Martin, Richard D.; Wilson, John; Chen, Caihua; Prather, Dennis W.

    2012-01-01

    Millimeter-wave (mmW) imaging has evolved to the point where it offers distinctive remote sensing capabilities in many application scenarios, such as port and harbor security, search and rescue, and navigational aids, due to its unique ability to penetrate atmospheric obscurants. Some of the applications being considered require passive imaging, imposing challenging sensitivity requirements to detect the low power levels in this spectral region. One metric used in this regard is the noise equivalent power (NEP), which quantifies the sensitivity of a detector. By utilizing a unique detector technology based on optical upconversion a low NEP value is achieved as compared to other RF methods, without the use of cryogenic cooling or low noise amplification. In addition, the overall size and weight may be reduced as compared to other imaging methodologies. As such, the construction and development of a passive mmW imaging system utilizing optical upconversion was undertaken, operating in the Q-Band to collect radiation between 33 and 50 GHz. Herein, we describe the passive mmW imager architecture and operation. Also presented are imaging results obtained using this approach as well as key imager metrics that have been experimentally validated.

  10. Investigation of Er3+, Yb3+, Nd3+ doped yttrium calcium oxyborate for photon upconversion applications

    NASA Astrophysics Data System (ADS)

    Kalidasan, M.; Baskar, K.; Dhanasekaran, R.

    2016-07-01

    In this work, investigation have been done on polycrystalline yttrium calcium oxyborate (YCa4O(BO3)3) for the realization of existence of second harmonic generation and other photon upconversion processes as concurrent effect with the aid of Er, Yb, Nd trivalent lanthanide ions. Pure, Er:Yb co-doped and Er:Yb:Nd triply-doped YCa4O(BO3)3 samples were prepared through solid state reaction and the phase identification has been done using powder X-ray diffraction spectral analysis. FTIR spectra show that the dopants increases the absorption of functional groups and modifies the lattice vibrational modes of YCa4O(BO3)3. The spectral overlap of optical absorption bands of Er3+, Yb3+, Nd3+ ions in 840 nm-1070 nm region indicates the prospect of energy transfer between these ions. The photoluminescence spectrum of Er:Yb:Nd triply doped sample show good enhancement compared to pure and Er:Yb co-doped YCa4O(BO3)3 samples. In the photon upconversion test carried out using 1064 nm Nd:YAG laser YCa4O(BO3)3:Er:Yb:Nd sample produced green light with efficiency higher than the other two samples. Surface morphology of the samples was recorded using field emission scanning electron microscope and analysed. The elemental composition of the samples has been confirmed by energy dispersive X-ray spectral analysis.

  11. Phytotoxicity, Translocation, and Biotransformation of NaYF₄ Upconversion Nanoparticles in a Soybean Plant.

    PubMed

    Yin, Wenyan; Zhou, Liangjun; Ma, Yuhui; Tian, Gan; Zhao, Jiating; Yan, Liang; Zheng, Xiaopeng; Zhang, Peng; Yu, Jie; Gu, Zhanjun; Zhao, Yuliang

    2015-09-01

    The increasing uses of rare-earth-doped upconversion nanoparticles (UCNPs) have obviously caused many concerns about their potential toxicology on live organisms. In addition, the UCNPs can be released into the environment, then transported into edible crop plants, and finally entered into food chain. Here, the soybean is chosen as a model plant to study the subchronic phytotoxicity, translocation, and biotransformation of NaYF4 UCNPs. The incubation with UCNPs at a relative low concentration of 10 μg mL(-1) leads to growth promotion for the roots and stems, while concentration exceeding 50 μg mL(-1) brings concentration-dependent inhibition. Upconversion luminescence imaging and scanning electron microscope characterization show that the UCNPs can be absorbed by roots and parts of the adsorbed UCNPs are then transported through vessels to stems and leaves. The near-edge X-ray absorption fine structure spectra reveal that the adsorbed NaYF4 nanoparticles are relatively stable during a 10 d incubation. Energy-dispersive X-ray spectrum further indicates that a small amount of NaYF4 is dissolved/digested and can transform into Y-phosphate clusters in roots.

  12. Enhancing the Imaging and Biosafety of Upconversion Nanoparticles through Phosphonate Coating

    PubMed Central

    Li, Ruibin; Ji, Zhaoxia; Dong, Juyao; Chang, Chong Hyun; Wang, Xiang; Sun, Bingbing; Wang, Meiying; Liao, Yu-Pei; Zink, Jeffrey I.; Nel, Andre E.; Xia, Tian

    2015-01-01

    Upconversion nanoparticles (UCNPs), which are generated by doping with rare earth (RE) metals, are increasingly used for bio-imaging because of the advantages they hold over conventional fluorophores. However, because pristine RE nanoparticles (NPs) are unstable in acidic physiological fluids (e.g., lysosomes), leading to intracellular phosphate complexation with the possibility of the lysosomal injury, it is important to ensure that UCNPs are safe designed. In this study, we used commercially available NaYF4: Er/Yb UCNPs to study their stability in lysosomes and simulated lysosomal fluid. We demonstrate that phosphate complexation leads to REPO4 deposition on the particle surfaces and morphological transformation. This leads to a decline in upconversion fluorescence efficiency as well as inducing pro-inflammatory effects at cellular level and in the intact lung. In order to preserve the imaging properties of the UCNPs as well as improve their safety, we experimented with a series of phosphonate chemical moieties to passivate particle surfaces through the strong coordination of the organophosphates with RE atoms. Particle screening and physicochemical characterization revealed that ethylenediaminetetra methylenephosphonic acid (EDTMP) surface coating provides the most stable UCNPs, which maintain their imaging intensity and do not induce pro-inflammatory effects in vitro and in vivo. In summary, phosphonate coating presents a safer design method that preserves and improves the bio-imaging properties of UCNPs, thereby enhancing their biological use. PMID:25727446

  13. Up-conversion luminescence polarization control in Er3+-doped NaYF4 nanocrystals

    NASA Astrophysics Data System (ADS)

    Hui, Zhang; Yun-Hua, Yao; Shi-An, Zhang; Chen-Hui, Lu; Zhen-Rong, Sun

    2016-02-01

    We propose a femtosecond laser polarization modulation scheme to control the up-conversion (UC) luminescence in Er3+-doped NaYF4 nanocrystals dispersed in the silicate glass. We show that the UC luminescence can be suppressed when the laser polarization is changed from linear through elliptical to circular, and the higher repetition rate will yield the lower control efficiency. We theoretically analyze the physical control mechanism of the UC luminescence polarization modulation by considering on- and near-resonant two-photon absorption, energy transfer up-conversion, and excited state absorption, and show that the polarization control mainly comes from the contribution of near-resonant two-photon absorption. Furthermore, we propose a method to improve the polarization control efficiency of UC luminescence in rare-earth ions by applying a two-color femtosecond laser field. Project supported by the Young Scientists Fund of the National Natural Science Foundation of China (Grant No. 11304396), the National Natural Science Foundation of China (Grant Nos. 11474096 and 51132004), and the Shanghai Municipal Science and Technology Commission, China (Grant No. 14JC1401500).

  14. Applications of optical upconversion to sparse aperture millimeter-wave imaging

    NASA Astrophysics Data System (ADS)

    Schuetz, C. A.; Mirotznik, M. S.; Shi, S.; Schneider, G. J.; Murakowski, J.; Prather, D. W.

    2005-11-01

    Passive millimeter-wave imagers have shown significant potential for use in applications that require penetration through atmospheric obscurations such a fog and smoke. However, the large apertures required to achieve sufficient diffraction-limited resolution in such systems often prohibit their use for many applications. One possible technique to circumvent this limitation is to use sparse-aperture imaging techniques. To date, such systems have not been realized because they require a high number of phase-sensitive, low-noise detectors spread over a large physical area. Collection and correlation processing of the data from this large array of sensors has not been practical using available technologies. Herein, we present the potential of optical upconversion detectors for sparse aperture imaging. The optical signals generated in such detectors preserve the phase information of the detected signal up until photodetection and may be easily routed to a central processor using low-loss optical fiber. Potential architectures for sparse aperture imagers using optical upconversion are discussed and compared to more traditional down-converted approaches. In addition, experimental results demonstrating the viability of such imagers are presented.

  15. Cascade-Avalanche Up-Conversion in Tm3+:YLF Crystals

    NASA Astrophysics Data System (ADS)

    Perlin, E. Yu.; Tkachuk, A. M.; Joubert, M.-F.; Moncorge, R.

    2001-05-01

    New efficient mechanisms of long-wavelength excitation of short-wavelength luminescence in a system of rare-earth impurity ions are proposed. The model studied involves a multilevel system of electronic states of a rare-earth ion interacting with the long-wavelength emission that is in resonance with one or several transitions between the excited levels. The concentration of impurity ions is assumed to be sufficiently high, so that the interionic cross-relaxation and the up-conversion play a significant role. Moreover, the model includes processes similar to photon avalanche, in which the photoinduced excitation of a single ion is converted into lower-level excitations of several ions, each of them reentering the process after photon absorption. Numerical solutions of the system of balance equations for a multilevel system are obtained with calculated and semiempirical parameters of self-quenching and up-conversion. It is shown that, in a system of Tm3+ impurity ions, short-wavelength luminescence at λ≥0.29 μm can be efficiently excited by radiation at λ≅1.11 or 0.649 μm with a moderate intensity.

  16. Blue and green upconversion emissions of Zr:Nd:LiNbO3 single crystals

    NASA Astrophysics Data System (ADS)

    Tang, Z. H.; Lin, S. P.; Ma, D. C.; Wang, B.

    2015-03-01

    Zr:Nd:LiNbO3 crystals codoped with 0.1 mol% of Nd2O3 and three concentrations of ZrO2 (0, 2 and 4 mol%) were grown by the Czochralski method from the congruent melt. The X-ray diffraction (XRD) patterns, UV-visible absorption and infrared (IR) spectra were measured to analyze the crystal composition and defect structure. The blue and green upconversion emissions of Nd3+ ions under 598 nm excitation were observed. The intensity of upconversion emissions was increased by the introduction of 2 mol% zirconium ion (Zr4+) and decreased by the introduction of 4 mol% Zr4+ ions. The luminescence decay measurement indicated that the 4G7/2 state of Nd3+ ion was mainly populated by excited state absorption process. It was proposed that Nd:LiNbO3 crystals doped with approximately 2 mol% Zr4+ ions could be applied as laser materials at 522/535 nm.

  17. New algorithm for nonlinear vector-based upconversion with center weighted medians

    NASA Astrophysics Data System (ADS)

    Blume, Holger

    1997-07-01

    One important task in the field of digital video signal processing is the conversion of one standard into another with different field and scan rates. Therefore a new vector-based nonlinear upconversion algorithm has been developed that applies nonlinear center weighted median filters (CWM). Assuming a two channel model of the human visual system with different spatio-temporal characteristics, there are contrary demands for the CWM filters. One can meet these demands by a vertical band separation and an application of so-called temporally and spatially dominated CWMs. By this means, interpolation errors of the separated channels can be compensated by an adequate splitting of the spectrum. Therefore a very robust vector error tolerant upconversion method can be achieved, which significantly improves the interpolation quality. By an appropriate choice of the CWM filter root structures, main picture elements are interpolated correctly even if faulty vector fields occur. To demonstrate the correctness of the deduced interpolation scheme, picture content is classified. These classes are distinguished by correct or incorrect vector assignment and correlated or noncorrelated picture content. The mode of operation of the new algorithm is portrayed for each class. Whereas the mode of operation for correlated picture content can be shown by object models, this is shown for noncorrelated picture content by the probability distribution function of the applied CWM filters. The new algorithm has been verified by objective evaluation methods [peak signal to noise ratio, and subjective mean square error measurements] and by a comprehensive subjective test series.

  18. Polyacrylic acid modified upconversion nanoparticles for simultaneous pH-triggered drug delivery and release imaging.

    PubMed

    Jia, Xuekun; Yin, Jinjin; He, Dinggeng; He, Xiaoxiao; Wang, Kemin; Chen, Mian; Li, Yuhong

    2013-12-01

    A poly(acrylicacid)-modified NaYF4:Yb, Er upconversion nanoparticles (PAA-UCNPs) with dual functions of drug delivery and release imaging have been successfully developed. The PAA polymer coated on the surface of UCNPs serve as a pH-sensitive nanovalve for loading drug molecules via electrostatic interaction. The drug-loading efficiency of the PAA-UCNPs was investigated by using doxorubicin hydrochloride (DOX) as a model anticancer drug to evaluate their potential as a delivery system. Results showed loading and releasing of DOX from PAA-UCNPs were controlled by varying pH, with high encapsulation rate at weak alkaline conditions and an increased drug dissociation rate in acidic environment, which is favorable for construct a pH-responsive controlled drug delivery system. The in vitro cytotoxicity test using HeLa cell line indicated that the DOX loaded PAA-UCNPs (DOX@PAA-UCNPs) were distinctly cytotoxic to HeLa cells, while the PAA-UCNPs were highly biocompatible and suitable to use as drug carriers. Furthermore, the upconversion fluorescence resonance energy transfer (UFRET) imaging through the two-photon laser scanning microscopy (TLSM) revealed the time course of intracellular delivery of DOX from DOX@PAA-UCNPs. Thus, PAA-UCNPs are effective for constructing pH-responsive controlled drug delivery systems for multi-functional cancer therapy and imaging. PMID:24266261

  19. Quantifying Aflatoxin B1 in peanut oil using fabricating fluorescence probes based on upconversion nanoparticles

    NASA Astrophysics Data System (ADS)

    Sun, Cuicui; Li, Huanhuan; Koidis, Anastasios; Chen, Quansheng

    2016-08-01

    Rare earth doped upconversion nanoparticles convert near-infrared excitation light into visible emission light. Compared to organic fluorophores and semiconducting nanoparticles, upconversion nanoparticles (UCNPs) offer high photochemical stability, sharp emission bandwidths, and large anti-Stokes shifts. Along with the significant light penetration depth and the absence of autofluorescence in biological samples under infrared excitation, these UCNPs have attracted more and more attention on toxin detection and biological labelling. Herein, the fluorescence probe based on UCNPs was developed for quantifying Aflatoxin B1 (AFB1) in peanut oil. Based on a specific immunity format, the detection limit for AFB1 under optimal conditions was obtained as low as 0.2 ng·ml- 1, and in the effective detection range 0.2 to 100 ng·ml- 1, good relationship between fluorescence intensity and AFB1 concentration was achieved under the linear ratios up to 0.90. Moreover, to check the feasibility of these probes on AFB1 measurements in peanut oil, recovery tests have been carried out. A good accuracy rating (93.8%) was obtained in this study. Results showed that the nanoparticles can be successfully applied for sensing AFB1 in peanut oil.

  20. Polymer encapsulated upconversion nanoparticle/iron oxide nanocomposites for multimodal imaging and magnetic targeted drug delivery.

    PubMed

    Xu, Huan; Cheng, Liang; Wang, Chao; Ma, Xinxing; Li, Yonggang; Liu, Zhuang

    2011-12-01

    Multimodal imaging and imaging-guided therapies have become a new trend in the current development of cancer theranostics. In this work, we encapsulate hydrophobic upconversion nanoparticles (UCNPs) together with iron oxide nanoparticles (IONPs) by using an amphiphilic block copolymer, poly (styrene-block-allyl alcohol) (PS(16)-b-PAA(10)), via a microemulsion method, obtaining an UC-IO@Polymer multi-functional nanocomposite system. Fluorescent dye and anti-cancer drug molecules can be further loaded inside the UC-IO@Polymer nanocomposite for additional functionalities. Utilizing the Squaraine (SQ) dye loaded nanocomposite (UC-IO@Polymer-SQ), triple-modal upconversion luminescence (UCL)/down-conversion fluorescence (FL)/magnetic resonance (MR) imaging is demonstrated in vitro and in vivo, and also applied for in vivo cancer cell tracking in mice. On the other hand, a chemotherapy drug, doxorubicin, is also loaded into the nanocomposite, forming an UC-IO@Polymer-DOX complex, which enables novel imaging-guided and magnetic targeted drug delivery. Our work provides a method to fabricate a nanocomposite system with highly integrated functionalities for multimodal biomedical imaging and cancer therapy.

  1. Protein modified upconversion nanoparticles for imaging-guided combined photothermal and photodynamic therapy.

    PubMed

    Chen, Qian; Wang, Chao; Cheng, Liang; He, Weiwei; Cheng, Zhengping; Liu, Zhuang

    2014-03-01

    In this work, we develop a multifunctional nano-platform by coating upconversion nanoparticles (UCNPs) with bovine serum albumin (BSA), obtaining UCNP@BSA nanoparticles with great solubility and stability in physiological environments. Two types of dye molecules, including a photosensitizer, Rose Bengal (RB), and an NIR-absorbing dye, IR825, can be simultaneously loaded into the BSA layer of the UCNP@BSA nanoparticles. In this carefully designed UCNP@BSA-RB&; IR825 system, RB absorbs green light emitted from UCNPs under 980-nm excitation to induce photodynamic cancer cell killing, while IR825 whose absorbance shows no overlap with upconversion excitation and emission wavelengths, offers nanoparticles a strong photothermal perform under 808-nm laser irradiation. Without showing noticeable dark toxicity, the obtained dual-dye loaded nanoparticles are able to kill cancer via combined photothermal and photodynamic therapies, both of which are induced by NIR light with high tissue penetration, by a synergetic manner both in vitro and in vivo. In addition, the intrinsic paramagnetic and optical properties of Gd(3+)-doped UCNPs can further be utilized for in vivo dual modal imaging. Our study suggests that UCNPs with well-designed surface engineering could serve as a multifunctional nano-platform promising in cancer theranostics. PMID:24412081

  2. Phytotoxicity, Translocation, and Biotransformation of NaYF₄ Upconversion Nanoparticles in a Soybean Plant.

    PubMed

    Yin, Wenyan; Zhou, Liangjun; Ma, Yuhui; Tian, Gan; Zhao, Jiating; Yan, Liang; Zheng, Xiaopeng; Zhang, Peng; Yu, Jie; Gu, Zhanjun; Zhao, Yuliang

    2015-09-01

    The increasing uses of rare-earth-doped upconversion nanoparticles (UCNPs) have obviously caused many concerns about their potential toxicology on live organisms. In addition, the UCNPs can be released into the environment, then transported into edible crop plants, and finally entered into food chain. Here, the soybean is chosen as a model plant to study the subchronic phytotoxicity, translocation, and biotransformation of NaYF4 UCNPs. The incubation with UCNPs at a relative low concentration of 10 μg mL(-1) leads to growth promotion for the roots and stems, while concentration exceeding 50 μg mL(-1) brings concentration-dependent inhibition. Upconversion luminescence imaging and scanning electron microscope characterization show that the UCNPs can be absorbed by roots and parts of the adsorbed UCNPs are then transported through vessels to stems and leaves. The near-edge X-ray absorption fine structure spectra reveal that the adsorbed NaYF4 nanoparticles are relatively stable during a 10 d incubation. Energy-dispersive X-ray spectrum further indicates that a small amount of NaYF4 is dissolved/digested and can transform into Y-phosphate clusters in roots. PMID:26099115

  3. Monodisperse Dual-Functional Upconversion Nanoparticles Enabled Near-Infrared Organolead Halide Perovskite Solar Cells.

    PubMed

    He, Ming; Pang, Xinchang; Liu, Xueqin; Jiang, Beibei; He, Yanjie; Snaith, Henry; Lin, Zhiqun

    2016-03-18

    Extending the spectral absorption of organolead halide perovskite solar cells from visible into near-infrared (NIR) range renders the minimization of non-absorption loss of solar photons with improved energy alignment. Herein, we report on, for the first time, a viable strategy of capitalizing on judiciously synthesized monodisperse NaYF4 :Yb/Er upconversion nanoparticles (UCNPs) as the mesoporous electrode for CH3 NH3 PbI3 perovskite solar cells and more importantly confer perovskite solar cells to be operative under NIR light. Uniform NaYF4 :Yb/Er UCNPs are first crafted by employing rationally designed double hydrophilic star-like poly(acrylic acid)-block-poly(ethylene oxide) (PAA-b-PEO) diblock copolymer as nanoreactor, imparting the solubility of UCNPs and the tunability of film porosity during the manufacturing process. The subsequent incorporation of NaYF4 :Yb/Er UCNPs as the mesoporous electrode led to a high efficiency of 17.8 %, which was further increased to 18.1 % upon NIR irradiation. The in situ integration of upconversion materials as functional components of perovskite solar cells offers the expanded flexibility for engineering the device architecture and broadening the solar spectral use.

  4. Monodisperse Dual-Functional Upconversion Nanoparticles Enabled Near-Infrared Organolead Halide Perovskite Solar Cells.

    PubMed

    He, Ming; Pang, Xinchang; Liu, Xueqin; Jiang, Beibei; He, Yanjie; Snaith, Henry; Lin, Zhiqun

    2016-03-18

    Extending the spectral absorption of organolead halide perovskite solar cells from visible into near-infrared (NIR) range renders the minimization of non-absorption loss of solar photons with improved energy alignment. Herein, we report on, for the first time, a viable strategy of capitalizing on judiciously synthesized monodisperse NaYF4 :Yb/Er upconversion nanoparticles (UCNPs) as the mesoporous electrode for CH3 NH3 PbI3 perovskite solar cells and more importantly confer perovskite solar cells to be operative under NIR light. Uniform NaYF4 :Yb/Er UCNPs are first crafted by employing rationally designed double hydrophilic star-like poly(acrylic acid)-block-poly(ethylene oxide) (PAA-b-PEO) diblock copolymer as nanoreactor, imparting the solubility of UCNPs and the tunability of film porosity during the manufacturing process. The subsequent incorporation of NaYF4 :Yb/Er UCNPs as the mesoporous electrode led to a high efficiency of 17.8 %, which was further increased to 18.1 % upon NIR irradiation. The in situ integration of upconversion materials as functional components of perovskite solar cells offers the expanded flexibility for engineering the device architecture and broadening the solar spectral use. PMID:26895302

  5. Absolute rate constant determinations for the deactivation of O/1D/ by time resolved decay of O/1D/ yields O/3P/ emission

    NASA Technical Reports Server (NTRS)

    Davidson, J. A.; Sadowski, C. M.; Schiff, H. I.; Howard, C. J.; Schmeltekopf, A. L.; Jennings, D. A.; Streit, G. E.

    1976-01-01

    Absolute rate constants for the deactivation of O(1D) atoms by some atmospheric gases have been determined by observing the time-resolved emission of O(1D) at 630 nm. O(1D) atoms were produced by the dissociation of ozone via repetitive laser pulses at 266 nm. Absolute rate constants for the relaxation of O(1D) at 298 K are reported for N2, O2, CO2, O3, H2, D2, CH4, HCl, NH3, H2O, N2O, and Ne. The results obtained are compared with previous relative and absolute measurements reported in the literature.

  6. Single-layer MoS2 nanosheet grafted upconversion nanoparticles for near-infrared fluorescence imaging-guided deep tissue cancer phototherapy

    NASA Astrophysics Data System (ADS)

    Han, Jianyu; Xia, Hongping; Wu, Yafeng; Kong, Shik Nie; Deivasigamani, Amudha; Xu, Rong; Hui, Kam M.; Kang, Yuejun

    2016-04-01

    A multifunctional nanostructure is prepared by covalently grafting upconversion nanoparticles (UCNPs) with chitosan functionalized MoS2 (MoS2-CS) and folic acid (FA) and then loading phthalocyanine (ZnPc) on the surface of MoS2, which integrates photodynamic therapy (PDT) with photothermal therapy (PTT) and upconversion luminescence imaging into one system for enhanced antitumor efficiency.A multifunctional nanostructure is prepared by covalently grafting upconversion nanoparticles (UCNPs) with chitosan functionalized MoS2 (MoS2-CS) and folic acid (FA) and then loading phthalocyanine (ZnPc) on the surface of MoS2, which integrates photodynamic therapy (PDT) with photothermal therapy (PTT) and upconversion luminescence imaging into one system for enhanced antitumor efficiency. Electronic supplementary information (ESI) available: Experimental details and figures. See DOI: 10.1039/c6nr00150e

  7. Enhancement of near-infrared to near-infrared upconversion emission in the CeO₂: Er³⁺, Tm³⁺, Yb³⁺ inverse opals.

    PubMed

    Wu, Hangjun; Yang, Zhengwen; Liao, Jiayan; Lai, Shenfeng; Qiu, Jianbei; Song, Zhiguo; Yang, Yong; Zhou, Dacheng

    2014-02-15

    In this Letter, CeO₂: Er³⁺, Tm³⁺, Yb³⁺ inverse opal with near-infrared to near-infrared upconversion emission was prepared by polystyrene colloidal crystal templates, and the influence of photonic bandgap on the upconversion emission was investigated. Comparing with the reference sample, suppression of the blue or red upconversion luminescence was observed in the inverse opals. It is interesting that the near-infrared upconversion emission located at about 803 nm was enhanced due to the inhibition of visible upconversion emission in the inverse opals. Additionally, the variety of upconversion emission mechanisms was observed and discussed in the CeO₂: Er³⁺, Tm³⁺, Yb³⁺ inverse opals. PMID:24562241

  8. Enhancement of near-infrared to near-infrared upconversion emission in the CeO₂: Er³⁺, Tm³⁺, Yb³⁺ inverse opals.

    PubMed

    Wu, Hangjun; Yang, Zhengwen; Liao, Jiayan; Lai, Shenfeng; Qiu, Jianbei; Song, Zhiguo; Yang, Yong; Zhou, Dacheng

    2014-02-15

    In this Letter, CeO₂: Er³⁺, Tm³⁺, Yb³⁺ inverse opal with near-infrared to near-infrared upconversion emission was prepared by polystyrene colloidal crystal templates, and the influence of photonic bandgap on the upconversion emission was investigated. Comparing with the reference sample, suppression of the blue or red upconversion luminescence was observed in the inverse opals. It is interesting that the near-infrared upconversion emission located at about 803 nm was enhanced due to the inhibition of visible upconversion emission in the inverse opals. Additionally, the variety of upconversion emission mechanisms was observed and discussed in the CeO₂: Er³⁺, Tm³⁺, Yb³⁺ inverse opals.

  9. Evidence against dopamine D1/D2 receptor heteromers

    PubMed Central

    Frederick, Aliya L.; Yano, Hideaki; Trifilieff, Pierre; Vishwasrao, Harshad D.; Biezonski, Dominik; Mészáros, József; Sibley, David R.; Kellendonk, Christoph; Sonntag, Kai C.; Graham, Devon L.; Colbran, Roger J.; Stanwood, Gregg D.; Javitch, Jonathan A.

    2014-01-01

    Hetero-oligomers of G-protein-coupled receptors have become the subject of intense investigation because their purported potential to manifest signaling and pharmacological properties that differ from the component receptors makes them highly attractive for the development of more selective pharmacological treatments. In particular, dopamine D1 and D2 receptors have been proposed to form hetero-oligomers that couple to Gαq proteins, and SKF83959 has been proposed to act as a biased agonist that selectively engages these receptor complexes to activate Gαq and thus phospholipase C. D1/D2 heteromers have been proposed as relevant to the pathophysiology and treatment of depression and schizophrenia. We used in vitro bioluminescence resonance energy transfer (BRET), ex vivo analyses of receptor localization and proximity in brain slices, and behavioral assays in mice to characterize signaling from these putative dimers/oligomers. We were unable to detect Gαq or Gα11 protein coupling to homomers or heteromers of D1 or D2 receptors using a variety of biosensors. SKF83959-induced locomotor and grooming behaviors were eliminated in D1 receptor knockout mice, verifying a key role for D1-like receptor activation. In contrast, SKF83959-induced motor responses were intact in D2 receptor and Gαq knockout mice, as well as in knock-in mice expressing a mutant Ala286-CaMKIIα, that cannot autophosphorylate to become active. Moreover, we found that in the shell of the nucleus accumbens, even in neurons in which D1 and D2 receptor promoters are both active, the receptor proteins are segregated and do not form complexes. These data are not compatible with SKF83959 signaling through Gαq or through a D1–D2 heteromer and challenge the existence of such a signaling complex in the adult animals that we used for our studies. PMID:25560761

  10. Dynamical functions of a 1D correlated quantum liquid

    NASA Astrophysics Data System (ADS)

    Carmelo, J. M. P.; Bozi, D.; Penc, K.

    2008-10-01

    The dynamical correlation functions in one-dimensional electronic systems show power-law behaviour at low energies and momenta close to integer multiples of the charge and spin Fermi momenta. These systems are usually referred to as Tomonaga-Luttinger liquids. However, near well defined lines of the (k,ω) plane the power-law behaviour extends beyond the low-energy cases mentioned above, and also appears at higher energies, leading to singular features in the photoemission spectra and other dynamical correlation functions. The general spectral-function expressions derived in this paper were used in recent theoretical studies of the finite-energy singular features in photoemission of the organic compound tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ) metallic phase. They are based on a so-called pseudofermion dynamical theory (PDT), which allows us to systematically enumerate and describe the excitations in the Hubbard model starting from the Bethe ansatz, as well as to calculate the charge and spin object phase shifts appearing as exponents of the power laws. In particular, we concentrate on the spin-density m\\rightarrow 0 limit and on effects in the vicinity of the singular border lines, as well as close to half filling. Our studies take into account spectral contributions from types of microscopic processes that do not occur for finite values of the spin density. In addition, the specific processes involved in the spectral features of TTF-TCNQ are studied. Our results are useful for the further understanding of the unusual spectral properties observed in low-dimensional organic metals and also provide expressions for the one- and two-atom spectral functions of a correlated quantum system of ultracold fermionic atoms in a 1D optical lattice with on-site two-atom repulsion.

  11. Synthesis, characterization, and physical properties of 1D nanostructures

    NASA Astrophysics Data System (ADS)

    Marley, Peter Mchael

    The roster of materials exhibiting metal---insulator transitions with sharply discontinuous switching of electrical conductivity close to room temperature remains rather sparse despite the fundamental interest in the electronic instabilities manifested in such materials and the plethora of potential technological applications, ranging from frequency-agile metamaterials to electrochromic coatings and Mott field-effect transistors. Vanadium oxide bronzes with the general formula MxV2O 5, provide a wealth of compositions and frameworks where strong electron correlation can be systematically (albeit thus far only empirically) tuned. Charge fluctuations along the quasi-1D frameworks of MxV 2O5 bronzes have evinced much recent interest owing to the manifestation of colossal metal---insulator transitions and superconductivity. We start with a general review on the phase transitions, both electronic and structural, of vanadium oxide bronzes in Chapter 1. In Chapter 2, we demonstrate an unprecedented reversible transformation between double-layered (delta) and tunnel (beta) quasi-1D geometries for nanowires of a divalent vanadium bronze CaxV2O5 (x ˜0.23) upon annealing-induced dehydration and hydrothermally-induced hydration. Such a facile hydration/dehydration-induced interconversion between two prominent quasi-1D structures (accompanied by a change in charge ordering motifs) has not been observed in the bulk and is posited to result from the ease of propagation of crystallographic slip processes across the confined nanowire widths for the delta→beta conversion and the facile diffusion of water molecules within the tunnel geometries for the beta→delta reversion. We demonstrate in Chapter 3 unprecedented pronounced metal-insulator transitions induced by application of a voltage for nanowires of a vanadium oxide bronze with intercalated divalent cations, beta-PbxV 2O5 (x ˜0.33). The induction of the phase transition through application of an electric field at room

  12. Synthesis, characterization, and physical properties of 1D nanostructures

    NASA Astrophysics Data System (ADS)

    Marley, Peter Mchael

    The roster of materials exhibiting metal---insulator transitions with sharply discontinuous switching of electrical conductivity close to room temperature remains rather sparse despite the fundamental interest in the electronic instabilities manifested in such materials and the plethora of potential technological applications, ranging from frequency-agile metamaterials to electrochromic coatings and Mott field-effect transistors. Vanadium oxide bronzes with the general formula MxV2O 5, provide a wealth of compositions and frameworks where strong electron correlation can be systematically (albeit thus far only empirically) tuned. Charge fluctuations along the quasi-1D frameworks of MxV 2O5 bronzes have evinced much recent interest owing to the manifestation of colossal metal---insulator transitions and superconductivity. We start with a general review on the phase transitions, both electronic and structural, of vanadium oxide bronzes in Chapter 1. In Chapter 2, we demonstrate an unprecedented reversible transformation between double-layered (delta) and tunnel (beta) quasi-1D geometries for nanowires of a divalent vanadium bronze CaxV2O5 (x ˜0.23) upon annealing-induced dehydration and hydrothermally-induced hydration. Such a facile hydration/dehydration-induced interconversion between two prominent quasi-1D structures (accompanied by a change in charge ordering motifs) has not been observed in the bulk and is posited to result from the ease of propagation of crystallographic slip processes across the confined nanowire widths for the delta→beta conversion and the facile diffusion of water molecules within the tunnel geometries for the beta→delta reversion. We demonstrate in Chapter 3 unprecedented pronounced metal-insulator transitions induced by application of a voltage for nanowires of a vanadium oxide bronze with intercalated divalent cations, beta-PbxV 2O5 (x ˜0.33). The induction of the phase transition through application of an electric field at room

  13. SCCRO3 (DCUN1D3) Antagonizes the Neddylation and Oncogenic Activity of SCCRO (DCUN1D1)*

    PubMed Central

    Huang, Guochang; Stock, Cameron; Bommeljé, Claire C.; Weeda, Víola B.; Shah, Kushyup; Bains, Sarina; Buss, Elizabeth; Shaha, Manish; Rechler, Willi; Ramanathan, Suresh Y.; Singh, Bhuvanesh

    2014-01-01

    The activity of cullin-RING type ubiquitination E3 ligases is regulated by neddylation, a process analogous to ubiquitination that culminates in covalent attachment of the ubiquitin-like protein Nedd8 to cullins. As a component of the E3 for neddylation, SCCRO/DCUN1D1 plays a key regulatory role in neddylation and, consequently, cullin-RING ligase activity. The essential contribution of SCCRO to neddylation is to promote nuclear translocation of the cullin-ROC1 complex. The presence of a myristoyl sequence in SCCRO3, one of four SCCRO paralogues present in humans that localizes to the membrane, raises questions about its function in neddylation. We found that although SCCRO3 binds to CAND1, cullins, and ROC1, it does not efficiently bind to Ubc12, promote cullin neddylation, or conform to the reaction processivity paradigms, suggesting that SCCRO3 does not have E3 activity. Expression of SCCRO3 inhibits SCCRO-promoted neddylation by sequestering cullins to the membrane, thereby blocking its nuclear translocation. Moreover, SCCRO3 inhibits SCCRO transforming activity. The inhibitory effects of SCCRO3 on SCCRO-promoted neddylation and transformation require both an intact myristoyl sequence and PONY domain, confirming that membrane localization and binding to cullins are required for in vivo functions. Taken together, our findings suggest that SCCRO3 functions as a tumor suppressor by antagonizing the neddylation activity of SCCRO. PMID:25349211

  14. Concentration of Yb3+ in Nanocrystalline Y2O3:Er3+, Yb3+ and Its Effect on the NIR-to-Green Upconversion Mechanism

    NASA Astrophysics Data System (ADS)

    Vetrone, Fiorenzo; Boyer, John-Christopher; Capobianco, John A.; Speghini, Adolfo; Bettinelli, Marco

    2004-03-01

    Nanocrystalline materials have been recognized to hold tremendous potential in the field of luminescence and thus are poised to revolutionize the display and imaging industries. Many of the commercially available technological devices employ inorganic polycrystalline materials doped with lanthanide ions as the main emissive component. Very recently, a great deal of research has focused on finding Ln3+-doped inorganic nanocrystalline materials that will undergo NIR-to-visible upconversion. Nanocrystalline Y2O3:Ln3+ is an ideal material to undergo upconversion as it possesses low vibrational energies, which renders the process more efficient. The tripositive erbium ion readily undergoes upconversion following excitation with NIR radiation. However, the absorption cross-section of the Er3+ ion in the NIR region is low. Thus, a codopant can be added to increase the absorption of the pump light and consequently, the upconversion efficiency. The ytterbium ion (Yb3+) is an ideal codopant as it possesses only one excited state with energy around 10 000 cm-1 but more importantly, the excited state of the Yb3+ ion has a much higher absorption cross-section than the 4I11/2 excited state of Er3+ thus rendering the upconversion much more efficient. However, the concentration of the Yb3+ ion is influential in the mechanism. In this paper we report the change in upconversion mechanisms, from a 2-photon to a 3-photon process, as the concentration of Yb3+ is increased in nanocrystalline Y2O3:Er3+.

  15. 1-D Tremor Streaks: Implications for a Streak Source Model

    NASA Astrophysics Data System (ADS)

    Houston, H.; Ghosh, A.; Vidale, J. E.

    2009-12-01

    Recent observations of non-volcanic tremor in Cascadia and Japan show “streaks” of tremor moving up and down dip in a convergence-parallel direction at “driving velocities” (i.e., 30 to 120 km/hr). Streak lengths of 30 to 40 km are occasionally observed. We explore the implications of these observations for a source model and spectrum of tremor. Key elements involve the extreme geometry and slow “rupture velocity” implied by the streaks. The source spectrum of tremor and other ETS seismic radiation exhibits a spectral falloff roughly as the inverse of frequency (1/f) in contrast to that of earthquakes, which follow a spectral falloff of 1/f squared above a corner frequency. Nevertheless, several observations suggest that the deformation that generates tremor is shear slip in the plate convergence direction. A fundamental question, then, has been what slip source could produce such an observed 1/f falloff over a wide frequency range. We propose a kinematic model, consistent with the 1-D geometry of the tremor streaks, in which fault displacement and width are strongly limited and rupture growth occurs only along fault length, which is oriented in a convergence-parallel direction (up or down dip). This is a version of the well-known Haskell model in which the durations of the two boxcars are very different. A 1/f spectral falloff holds between the corner frequencies associated with the two durations. Thus, the frequency range of the observed 1/f spectral falloff of tremor provides constraints on the durations of the boxcars. Further constraints involve the maximum likely displacement in an ETS event, the rupture velocities of the streaks, and the moment release rate. The narrow streak geometry implies fairly high strain and stress drops, in contrast to the low overall stress drops inferred from tidal modulation of tremor and the low strain across the entire ETS region. The observation of tremor streaks migrating at 10's of km/hour, in conjunction with the

  16. Human CD1d knock-in mouse model demonstrates potent antitumor potential of human CD1d-restricted invariant natural killer T cells

    PubMed Central

    Wen, Xiangshu; Rao, Ping; Carreño, Leandro J.; Kim, Seil; Lawrenczyk, Agnieszka; Porcelli, Steven A.; Cresswell, Peter; Yuan, Weiming

    2013-01-01

    Despite a high degree of conservation, subtle but important differences exist between the CD1d antigen presentation pathways of humans and mice. These differences may account for the minimal success of natural killer T (NKT) cell-based antitumor therapies in human clinical trials, which contrast strongly with the powerful antitumor effects in conventional mouse models. To develop an accurate model for in vivo human CD1d (hCD1d) antigen presentation, we have generated a hCD1d knock-in (hCD1d-KI) mouse. In these mice, hCD1d is expressed in a native tissue distribution pattern and supports NKT cell development. Reduced numbers of invariant NKT (iNKT) cells were observed, but at an abundance comparable to that in most normal humans. These iNKT cells predominantly expressed mouse Vβ8, the homolog of human Vβ11, and phenotypically resembled human iNKT cells in their reduced expression of CD4. Importantly, iNKT cells in hCD1d knock-in mice exert a potent antitumor function in a melanoma challenge model. Our results show that replacement of mCD1d by hCD1d can select a population of functional iNKT cells closely resembling human iNKT cells. These hCD1d knock-in mice will allow more accurate in vivo modeling of human iNKT cell responses and will facilitate the preclinical assessment of iNKT cell-targeted antitumor therapies. PMID:23382238

  17. Annihilation limit of a visible-to-UV photon upconversion composition ascertained from transient absorption kinetics.

    PubMed

    Deng, Fan; Blumhoff, Jörg; Castellano, Felix N

    2013-05-30

    Noncoherent sensitized green-to-near-visible upconversion has been achieved utilizing palladium(II) octaethylporphyrin (PdOEP) as the triplet sensitizer and anthracene as the energy acceptor/annihilator in vacuum degassed toluene. Selective 547 nm excitation of PdOEP with incident irradiance as low as 600 μW/cm(2) results in the observation of anthryl fluorescence at higher energy. Stern-Volmer analysis of the dynamic phosphorescence quenching of PdOEP by anthracene possesses an extremely large K(SV) of 810,000 M(-1), yielding a triplet-triplet energy transfer quenching constant of 3.3 × 10(9) M(-1) s(-1). Clear evidence for the subsequent triplet-triplet annihilation (TTA) of anthracene was afforded by numerous experiments, one of the most compelling was an excitation scan illustrating that the Q-band absorption features of PdOEP are solely responsible for sensitizing the anti-Stokes fluorescence. The upconverted emission intensity with respect to the excitation power was shown to vary between quadratic and linear using either coherent or noncoherent light sources, illustrating the expected kinetic limits for the light producing photochemistry under continuous wave illumination. Time-resolved experiments directly comparing the total integrated anthracene intensity/time fluorescence data produced through upconversion (λ(ex) = 547 nm, delayed signal) and with direct excitation (λ(ex) = 355 nm, prompt signal) under conditions where the laser pulse is completely absorbed by the sample reveal annihilation efficiencies of approximately 40%. Similarly, the delayed fluorescence kinetic analysis reported by Schmidt and co-workers (J. Phys. Chem. Lett. 2010, 1, 1795-1799) was used to reveal the maximum possible efficiency from a model red-to-yellow upconverting composition and this treatment was applied to the anthryl triplet absorption decay transients of anthracene measured for the PdOEP/anthracene composition at 430 nm. From this analysis approximately 50% of the

  18. Proteasome-mediated degradation antagonizes critical levels of the apoptosis-inducing C1D protein

    PubMed Central

    Rothbarth, Karsten; Stammer, Hermann; Werner, Dieter

    2002-01-01

    The C1D gene is expressed in a broad spectrum of mammalian cells and tissues but its product induces apoptotic cell death when exceeding a critical level. Critical levels are achieved in a fraction of cells by transient transfection with EGFP-tagged C1D expression constructs. However, transfected cells expressing sub-critical levels of C1D(EGFP) escape apoptotic cell death by activation of a proteasome-mediated rescue mechanism. Inhibition of the proteasome-dependent degradation of the C1D(EGFP) protein results in a parallel increase of the intracellular C1D level and in the fraction of apoptotic cells. PMID:12379155

  19. A cobalt oxyhydroxide-modified upconversion nanosystem for sensitive fluorescence sensing of ascorbic acid in human plasma

    NASA Astrophysics Data System (ADS)

    Cen, Yao; Tang, Jun; Kong, Xiang-Juan; Wu, Shuang; Yuan, Jing; Yu, Ru-Qin; Chu, Xia

    2015-08-01

    Ascorbic acid (AA), a potent antioxidant readily scavenging reactive species, is a crucial micronutrient involved in many biochemical processes. Here, we have developed a cobalt oxyhydroxide (CoOOH)-modified upconversion nanosystem for fluorescence sensing of AA activity in human plasma. The nanosystem consists of upconversion nanoparticles (UCNPs) NaYF4:30% Yb,0.5% Tm@NaYF4, which serve as energy donors, and CoOOH nanoflakes formed on the surface of UCNPs, which act as efficient energy acceptors. The fluorescence resonance energy transfer (FRET) process from the UCNPs to the absorbance of the CoOOH nanoflakes occurs in the nanosystem. The AA-mediated specific redox reaction reduces CoOOH into Co2+, leading to the inhibition of FRET, and resulting in the recovery of upconversion emission spectra. On the basis of these features, the nanosystem can be used for sensing AA activity with sensitivity and selectivity. Moreover, due to the minimizing background interference provided by UCNPs, the nanosystem has been applied to monitoring AA levels in human plasma sample with satisfactory results. The proposed approach may potentially provide an analytical platform for research and clinical diagnosis of AA related diseases.Ascorbic acid (AA), a potent antioxidant readily scavenging reactive species, is a crucial micronutrient involved in many biochemical processes. Here, we have developed a cobalt oxyhydroxide (CoOOH)-modified upconversion nanosystem for fluorescence sensing of AA activity in human plasma. The nanosystem consists of upconversion nanoparticles (UCNPs) NaYF4:30% Yb,0.5% Tm@NaYF4, which serve as energy donors, and CoOOH nanoflakes formed on the surface of UCNPs, which act as efficient energy acceptors. The fluorescence resonance energy transfer (FRET) process from the UCNPs to the absorbance of the CoOOH nanoflakes occurs in the nanosystem. The AA-mediated specific redox reaction reduces CoOOH into Co2+, leading to the inhibition of FRET, and resulting in the

  20. Core-shell hybrid upconversion nanoparticles carrying stable nitroxide radicals as potential multifunctional nanoprobes for upconversion luminescence and magnetic resonance dual-modality imaging

    NASA Astrophysics Data System (ADS)

    Chen, Chuan; Kang, Ning; Xu, Ting; Wang, Dong; Ren, Lei; Guo, Xiangqun

    2015-03-01

    Nitroxide radicals, such as 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) and its derivatives, have recently been used as contrast agents for magnetic resonance imaging (MRI) and electron paramagnetic resonance imaging (EPRI). However, their rapid one-electron bioreduction to diamagnetic N-hydroxy species when administered intravenously has limited their use in in vivo applications. In this article, a new approach of silica coating for carrying stable radicals was proposed. A 4-carboxyl-TEMPO nitroxide radical was covalently linked with 3-aminopropyl-trimethoxysilane to produce a silanizing TEMPO radical. Utilizing a facile reaction based on the copolymerization of silanizing TEMPO radicals with tetraethyl orthosilicate in reverse microemulsion, a TEMPO radicals doped SiO2 nanostructure was synthesized and coated on the surface of NaYF4:Yb,Er/NaYF4 upconversion nanoparticles (UCNPs) to generate a novel multifunctional nanoprobe, PEGylated UCNP@TEMPO@SiO2 for upconversion luminescence (UCL) and magnetic resonance dual-modality imaging. The electron spin resonance (ESR) signals generated by the TEMPO@SiO2 show an enhanced reduction resistance property for a period of time of up to 1 h, even in the presence of 5 mM ascorbic acid. The longitudinal relaxivity of PEGylated UCNPs@TEMPO@SiO2 nanocomposites is about 10 times stronger than that for free TEMPO radicals. The core-shell NaYF4:Yb,Er/NaYF4 UCNPs synthesized by this modified user-friendly one-pot solvothermal strategy show a significant enhancement of UCL emission of up to 60 times more than the core NaYF4:Yb,Er. Furthermore, the PEGylated UCNP@TEMPO@SiO2 nanocomposites were further used as multifunctional nanoprobes to explore their performance in the UCL imaging of living cells and T1-weighted MRI in vitro and in vivo.Nitroxide radicals, such as 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) and its derivatives, have recently been used as contrast agents for magnetic resonance imaging (MRI) and electron

  1. Core-shell hybrid upconversion nanoparticles carrying stable nitroxide radicals as potential multifunctional nanoprobes for upconversion luminescence and magnetic resonance dual-modality imaging

    NASA Astrophysics Data System (ADS)

    Chen, Chuan; Kang, Ning; Xu, Ting; Wang, Dong; Ren, Lei; Guo, Xiangqun

    2015-03-01

    Nitroxide radicals, such as 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) and its derivatives, have recently been used as contrast agents for magnetic resonance imaging (MRI) and electron paramagnetic resonance imaging (EPRI). However, their rapid one-electron bioreduction to diamagnetic N-hydroxy species when administered intravenously has limited their use in in vivo applications. In this article, a new approach of silica coating for carrying stable radicals was proposed. A 4-carboxyl-TEMPO nitroxide radical was covalently linked with 3-aminopropyl-trimethoxysilane to produce a silanizing TEMPO radical. Utilizing a facile reaction based on the copolymerization of silanizing TEMPO radicals with tetraethyl orthosilicate in reverse microemulsion, a TEMPO radicals doped SiO2 nanostructure was synthesized and coated on the surface of NaYF4:Yb,Er/NaYF4 upconversion nanoparticles (UCNPs) to generate a novel multifunctional nanoprobe, PEGylated UCNP@TEMPO@SiO2 for upconversion luminescence (UCL) and magnetic resonance dual-modality imaging. The electron spin resonance (ESR) signals generated by the TEMPO@SiO2 show an enhanced reduction resistance property for a period of time of up to 1 h, even in the presence of 5 mM ascorbic acid. The longitudinal relaxivity of PEGylated UCNPs@TEMPO@SiO2 nanocomposites is about 10 times stronger than that for free TEMPO radicals. The core-shell NaYF4:Yb,Er/NaYF4 UCNPs synthesized by this modified user-friendly one-pot solvothermal strategy show a significant enhancement of UCL emission of up to 60 times more than the core NaYF4:Yb,Er. Furthermore, the PEGylated UCNP@TEMPO@SiO2 nanocomposites were further used as multifunctional nanoprobes to explore their performance in the UCL imaging of living cells and T1-weighted MRI in vitro and in vivo.Nitroxide radicals, such as 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) and its derivatives, have recently been used as contrast agents for magnetic resonance imaging (MRI) and electron

  2. Grid Cell Responses in 1D Environments Assessed as Slices through a 2D Lattice.

    PubMed

    Yoon, KiJung; Lewallen, Sam; Kinkhabwala, Amina A; Tank, David W; Fiete, Ila R

    2016-03-01

    Grid cells, defined by their striking periodic spatial responses in open 2D arenas, appear to respond differently on 1D tracks: the multiple response fields are not periodically arranged, peak amplitudes vary across fields, and the mean spacing between fields is larger than in 2D environments. We ask whether such 1D responses are consistent with the system's 2D dynamics. Combining analytical and numerical methods, we show that the 1D responses of grid cells with stable 1D fields are consistent with a linear slice through a 2D triangular lattice. Further, the 1D responses of comodular cells are well described by parallel slices, and the offsets in the starting points of the 1D slices can predict the measured 2D relative spatial phase between the cells. From these results, we conclude that the 2D dynamics of these cells is preserved in 1D, suggesting a common computation during both types of navigation behavior. PMID:26898777

  3. Temperature-feedback upconversion nanocomposite for accurate photothermal therapy at facile temperature

    NASA Astrophysics Data System (ADS)

    Zhu, Xingjun; Feng, Wei; Chang, Jian; Tan, Yan-Wen; Li, Jiachang; Chen, Min; Sun, Yun; Li, Fuyou

    2016-02-01

    Photothermal therapy (PTT) at present, following the temperature definition for conventional thermal therapy, usually keeps the temperature of lesions at 42-45 °C or even higher. Such high temperature kills cancer cells but also increases the damage of normal tissues near lesions through heat conduction and thus brings about more side effects and inhibits therapeutic accuracy. Here we use temperature-feedback upconversion nanoparticle combined with photothermal material for real-time monitoring of microscopic temperature in PTT. We observe that microscopic temperature of photothermal material upon illumination is high enough to kill cancer cells when the temperature of lesions is still low enough to prevent damage to normal tissue. On the basis of the above phenomenon, we further realize high spatial resolution photothermal ablation of labelled tumour with minimal damage to normal tissues in vivo. Our work points to a method for investigating photothermal properties at nanoscale, and for the development of new generation of PTT strategy.

  4. Temperature-feedback upconversion nanocomposite for accurate photothermal therapy at facile temperature.

    PubMed

    Zhu, Xingjun; Feng, Wei; Chang, Jian; Tan, Yan-Wen; Li, Jiachang; Chen, Min; Sun, Yun; Li, Fuyou

    2016-02-04

    Photothermal therapy (PTT) at present, following the temperature definition for conventional thermal therapy, usually keeps the temperature of lesions at 42-45 °C or even higher. Such high temperature kills cancer cells but also increases the damage of normal tissues near lesions through heat conduction and thus brings about more side effects and inhibits therapeutic accuracy. Here we use temperature-feedback upconversion nanoparticle combined with photothermal material for real-time monitoring of microscopic temperature in PTT. We observe that microscopic temperature of photothermal material upon illumination is high enough to kill cancer cells when the temperature of lesions is still low enough to prevent damage to normal tissue. On the basis of the above phenomenon, we further realize high spatial resolution photothermal ablation of labelled tumour with minimal damage to normal tissues in vivo. Our work points to a method for investigating photothermal properties at nanoscale, and for the development of new generation of PTT strategy.

  5. Efficient near-infrared up-conversion photoluminescence in carbon nanotubes

    PubMed Central

    Akizuki, Naoto; Aota, Shun; Mouri, Shinichiro; Matsuda, Kazunari; Miyauchi, Yuhei

    2015-01-01

    Photoluminescence phenomena normally obey Stokes' law of luminescence according to which the emitted photon energy is typically lower than its excitation counterparts. Here we show that carbon nanotubes break this rule under one-photon excitation conditions. We found that the carbon nanotubes exhibit efficient near-infrared photoluminescence upon photoexcitation even at an energy lying >100–200 meV below that of the emission at room temperature. This apparently anomalous phenomenon is attributed to efficient one-phonon-assisted up-conversion processes resulting from unique excited-state dynamics emerging in an individual carbon nanotube with accidentally or intentionally embedded localized states. These findings may open new doors for energy harvesting, optoelectronics and deep-tissue photoluminescence imaging in the near-infrared optical range. PMID:26568250

  6. A facile method for high-performance multicolor upconversion microrods for biological encoding.

    PubMed

    Su, Lin; Gong, Xiaoqun; Wang, Sheng; Li, Xue; Zhang, Ying; Dou, Yan; Yang, Wentao; Wang, Hanjie; Chang, Jin

    2015-11-13

    In this paper, we demonstrate a facile method for preparing high-performance multicolor upconversion (UC) microrods for biological encoding. Multicolor UC microrods were prepared through a one-step facile hydrothermal method. The as-prepared UC microrods were uniform in shape and size (about 2 μm in length). For bioconjugation, the UC microrods were functionalized by coating with an amino-terminated silica shell. In order to magnify the bioactive sites, poly (acrylic acid) was introduced to the surface of UC microrods. The optical micrographs displayed that the carboxylated UC microrods were bright enough for observation of single crystals by a conventional microscope. They also exhibited excellent fluorescence stability against time expansion and pH change. Furthermore, a conventional optical microscope can readout the results of a sandwich immunoassay that was conducted by the UC microrods. All the results indicated that the UC microrods exhibited great potential to be new encoding particles for biological molecules.

  7. Passive 77 GHz millimeter-wave sensor based on optical upconversion.

    PubMed

    Wilson, John P; Schuetz, Christopher A; Dillon, Thomas E; Yao, Peng; Harrity, Charles E; Prather, Dennis W

    2012-06-20

    A passive millimeter-wave (mmW) sensor operating at a frequency of 77 GHz is built and characterized. The sensor is a single pixel sensor that raster scans to create an image. Optical upconversion is used to convert the incident mmW signal into an optical signal for detection. Components were picked to be representative of a single element in a distributed aperture system. The performance of the system is analyzed, and the noise equivalent temperature difference is found to be 0.5 K (for a 1 s integration time) with a diffraction limited resolution of ~8 mrad. Representative images are shown that demonstrate the phenomenology associated with this spectrum.

  8. Nanopatterned PMMA-Yb:Er/Tm:Lu2O3 composites with visible upconversion emissions.

    PubMed

    Han, X; Maiz, J; Mijangos, C; Zaldo, C

    2014-05-23

    Nanopillars, nanotubes and nanofibers of transparent polymethyl methacrylate (PMMA) polymer with Yb:Ln:Lu2O3 (Ln = Er or Tm) nanoparticles (NPs) (≈30-35 nm average size) have been prepared by infiltration of anodized aluminum oxide hexagonally nanopatterned templates. The outer diameter of these nanostructures is in the 330-400 nm range, with lengths up to 50 μm and a period distance of 430 nm. These nanostructures show visible upconversion (UC) emissions under excitation with 978 nm light. The steady state temperature of the polymer nanostructures is optically evidenced by the Er(3+) UC emission and optically controlled around the PMMA glass transition temperature by the excitation light, introducing a new method for NP storage in a solid and potential optically induced particle release. Full color emission is shown in tridoped (Yb:Er:Tm) samples. PMID:24784527

  9. Upconversion nanoparticle-based fluorescence resonance energy transfer assay for organophosphorus pesticides.

    PubMed

    Long, Qian; Li, Haitao; Zhang, Youyu; Yao, Shouzhuo

    2015-06-15

    This paper reports a novel nanosensor for organophosphorus pesticides based on the fluorescence resonance energy transfer (FRET) between NaYF4:Yb,Er upconversion nanoparticles (UCNPs) and gold nanoparticles (AuNPs). The detection mechanism is based on the facts that AuNPs quench the fluorescence of UCNPs and organophosphorus pesticides (OPs) inhibit the activity of acetylcholinesterase (AChE) which catalyzes the hydrolysis of acetylthiocholine (ATC) into thiocholine. Under the optimized conditions, the logarithm of the pesticides concentration was proportional to the inhibition efficiency. The detection limits of parathion-methyl, monocrotophos and dimethoate reached 0.67, 23, and 67 ng/L, respectively. Meanwhile, the biosensor shows good sensitivity, stability, and could be successfully applied to detection of OPs in real food samples, suggesting the biosensor has potentially extensive application clinic diagnoses assays.

  10. Frame rate upconversion using pyramid structure and dense motion vector fields

    NASA Astrophysics Data System (ADS)

    Kim, Jun-Geon; Lee, Daeho

    2016-05-01

    We propose a frame rate upconversion (FRUC) method using pyramid structures (PS) and dense motion vector fields (MVFs). In FRUC processes, performance is dominantly dependent on motion compensation, thus motion vectors (MVs) must be precisely estimated. Variable sizes of blocks and large search ranges are needed to estimate the MVs of large objects and large movements; however, we use PS and dense MVFs to estimate MVs for various conditions. In the PS, we first estimate MVs on level 0, which is the most reduced image in the PS (L-1 times downsampling), and MVs on the high levels are estimated except for pixels having large corresponding MVs on the lower levels. Integration of MVFs for all levels is followed by a vector median filter to remove noises. Finally, a motion compensated frame is interpolated by weight-overlapped block motion compensation.

  11. Broadband Near-Infrared to Visible Upconversion in Quantum Dot-Quantum Well Heterostructures.

    PubMed

    Teitelboim, Ayelet; Oron, Dan

    2016-01-26

    Upconversion is a nonlinear process in which two, or more, long wavelength photons are converted to a shorter wavelength photon. It holds great promise for bioimaging, enabling spatially resolved imaging in a scattering specimen and for photovoltaic devices as a means to surpass the Shockley-Queisser efficiency limit. Here, we present dual near-infrared and visible emitting PbSe/CdSe/CdS nanocrystals able to upconvert a broad range of NIR wavelengths to visible emission at room temperature. The synthesis is a three-step process, which enables versatility and tunability of both the visible emission color and the NIR absorption edge. Using this method, one can achieve a range of desired upconverted emission peak positions with a suitable NIR band gap. PMID:26592258

  12. White-Light Emission from an Integrated Upconversion Nanostructure: Toward Multicolor Displays Modulated by Laser Power.

    PubMed

    Zhang, Cheng; Yang, Liang; Zhao, Jun; Liu, Bianhua; Han, Ming-Yong; Zhang, Zhongping

    2015-09-21

    The white backlight in displays is generated by optimizing the proportions of individual emitters with different wavelengths by variations in materials composition, phase, and structure. Color pixels usually result from the separation of white light or the excitation with multiwavelength or multipulse sources. However, it is a challenge to develop a material that comprises a single structure and emits over the full visible spectrum, but where the emission wavelengths can be controlled by a simple excitation source. Herein, we report an upconversion nanostructure that incorporates several lanthanide ions in the same core@shell@shell structure. The combination of multiple narrow spectral bands results in the emission of white light. The emission colors can be tuned by changing the excitation power density, which manipulates the photon transfer pathways. Applications such as flat-panel displays and imaging have been demonstrated. PMID:26213285

  13. In vivo 808 nm image-guided photodynamic therapy based on an upconversion theranostic nanoplatform

    NASA Astrophysics Data System (ADS)

    Liu, Xiaomin; Que, Ivo; Kong, Xianggui; Zhang, Youlin; Tu, Langping; Chang, Yulei; Wang, Tong Tong; Chan, Alan; Löwik, Clemens W. G. M.; Zhang, Hong

    2015-09-01

    A new strategy for efficient in vivo image-guided photodynamic therapy (PDT) has been demonstrated utilizing a ligand-exchange constructed upconversion-C60 nanophotosensitizer. This theranostic platform is superior to the currently reported nanophotosensitizers in (i) directly bonding photosensitizer C60 to the surface of upconversion nanoparticles (UCNPs) by a smart ligand-exchange strategy, which greatly shortened the energy transfer distance and enhanced the 1O2 production, resulting in the improvement of the therapeutic effect; (ii) realizing in vivo NIR 808 nm image-guided PDT with both excitation (980 nm) and emission (808 nm) light falling in the biological window of tissues, which minimized auto-fluorescence, reduced light scatting and improved the imaging contrast and depth, and thus guaranteed noninvasive diagnostic accuracy. In vivo and ex vivo tests demonstrated its favorable bio-distribution, tumor-selectivity and high therapeutic efficacy. Owing to the effective ligand exchange strategy and the excellent intrinsic photophysical properties of C60, 1O2 production yield was improved, suggesting that a low 980 nm irradiation dosage (351 J cm-2) and a short treatment time (15 min) were sufficient to perform NIR (980 nm) to NIR (808 nm) image-guided PDT. Our work enriches the understanding of UCNP-based PDT nanophotosensitizers and highlights their potential use in future NIR image-guided noninvasive deep cancer therapy.A new strategy for efficient in vivo image-guided photodynamic therapy (PDT) has been demonstrated utilizing a ligand-exchange constructed upconversion-C60 nanophotosensitizer. This theranostic platform is superior to the currently reported nanophotosensitizers in (i) directly bonding photosensitizer C60 to the surface of upconversion nanoparticles (UCNPs) by a smart ligand-exchange strategy, which greatly shortened the energy transfer distance and enhanced the 1O2 production, resulting in the improvement of the therapeutic effect; (ii

  14. Regiospecific Hetero-Assembly of DNA-Functionalized Plasmonic Upconversion Superstructures.

    PubMed

    Li, Le-Le; Lu, Yi

    2015-04-29

    We report a novel strategy for regiospecific hetero-assembly of DNA-modified gold nanoparticles (DNA-AuNPs) onto upconversion nanoparticles (UCNPs) into hybrid lab-on-a-particle systems. The DNA-AuNPs have been assembled onto the hexagonal plate-like UCNPs with well-regulated stoichiometry and controlled organization onto the different facets of UCNP, forming various addressable superstructures. The fine-tuning of stoichiometry and organization is realized by biorecognition specificity of DNA toward specific crystal facets of UCNPs. Such a hetero-assembled DNA-AuNP/UCNP system maintains both plasmonic resonance of AuNPs and fluorescent properties of UCNPs, allowing targeted dual-modality imaging of cancer cells using an aptamer.

  15. Depth-Resolved Multispectral Sub-Surface Imaging Using Multifunctional Upconversion Phosphors with Paramagnetic Properties

    PubMed Central

    Ovanesyan, Zaven; Mimun, L. Christopher; Kumar, Gangadharan Ajith; Yust, Brian G.; Dannangoda, Chamath; Martirosyan, Karen S.; Sardar, Dhiraj K.

    2015-01-01

    Molecular imaging is very promising technique used for surgical guidance, which requires advancements related to properties of imaging agents and subsequent data retrieval methods from measured multispectral images. In this article, an upconversion material is introduced for subsurface near-infrared imaging and for the depth recovery of the material embedded below the biological tissue. The results confirm significant correlation between the analytical depth estimate of the material under the tissue and the measured ratio of emitted light from the material at two different wavelengths. Experiments with biological tissue samples demonstrate depth resolved imaging using the rare earth doped multifunctional phosphors. In vitro tests reveal no significant toxicity, whereas the magnetic measurements of the phosphors show that the particles are suitable as magnetic resonance imaging agents. The confocal imaging of fibroblast cells with these phosphors reveals their potential for in vivo imaging. The depth-resolved imaging technique with such phosphors has broad implications for real-time intraoperative surgical guidance. PMID:26322519

  16. Regiospecific Hetero-Assembly of DNA-Functionalized Plasmonic Upconversion Superstructures

    PubMed Central

    2015-01-01

    We report a novel strategy for regiospecific hetero-assembly of DNA-modified gold nanoparticles (DNA-AuNPs) onto upconversion nanoparticles (UCNPs) into hybrid lab-on-a-particle systems. The DNA-AuNPs have been assembled onto the hexagonal plate-like UCNPs with well-regulated stoichiometry and controlled organization onto the different facets of UCNP, forming various addressable superstructures. The fine-tuning of stoichiometry and organization is realized by biorecognition specificity of DNA toward specific crystal facets of UCNPs. Such a hetero-assembled DNA-AuNP/UCNP system maintains both plasmonic resonance of AuNPs and fluorescent properties of UCNPs, allowing targeted dual-modality imaging of cancer cells using an aptamer. PMID:25853565

  17. Three-dimensional micro-printing of temperature sensors based on up-conversion luminescence

    SciTech Connect

    Wickberg, Andreas; Mueller, Jonathan B.; Mange, Yatin J.; Nann, Thomas; Fischer, Joachim; Wegener, Martin

    2015-03-30

    The pronounced temperature dependence of up-conversion luminescence from nanoparticles doped with rare-earth elements enables local temperature measurements. By mixing these nanoparticles into a commercially available photoresist containing the low-fluorescence photo-initiator Irgacure 369, and by using three-dimensional direct laser writing, we show that micrometer sized local temperature sensors can be positioned lithographically as desired. Positioning is possible in pre-structured environments, e.g., within buried microfluidic channels or on optical or electronic chips. We use the latter as an example and demonstrate the measurement for both free space and waveguide-coupled excitation and detection. For the free space setting, we achieve a temperature standard deviation of 0.5 K at a time resolution of 1 s.

  18. Efficient near-infrared up-conversion photoluminescence in carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Akizuki, Naoto; Aota, Shun; Mouri, Shinichiro; Matsuda, Kazunari; Miyauchi, Yuhei

    2015-11-01

    Photoluminescence phenomena normally obey Stokes' law of luminescence according to which the emitted photon energy is typically lower than its excitation counterparts. Here we show that carbon nanotubes break this rule under one-photon excitation conditions. We found that the carbon nanotubes exhibit efficient near-infrared photoluminescence upon photoexcitation even at an energy lying >100-200 meV below that of the emission at room temperature. This apparently anomalous phenomenon is attributed to efficient one-phonon-assisted up-conversion processes resulting from unique excited-state dynamics emerging in an individual carbon nanotube with accidentally or intentionally embedded localized states. These findings may open new doors for energy harvesting, optoelectronics and deep-tissue photoluminescence imaging in the near-infrared optical range.

  19. Portable Upconversion Nanoparticles-Based Paper Device for Field Testing of Drug Abuse.

    PubMed

    He, Mengyuan; Li, Zhen; Ge, Yiying; Liu, Zhihong

    2016-02-01

    We report the first portable upconversion nanoparticles (UCNPs)-based paper device for road-side field testing of cocaine. Upon the recognition of cocaine by two pieces of rationally designed aptamer fragments, the luminescence of UCNPs immobilized on the paper is quenched by Au nanoparticles (AuNPs), which indicates the cocaine concentration. This device can give quantitative results in a short time with high sensitivity using only a smartphone as the apparatus. Moreover, this device is applicable in human saliva samples, and it also can be used to monitor the cocaine content change in blood samples. The results of this work demonstrate the prospect of developing UCNPs-based paper devices for field testing of drug abuse.

  20. PHOTONIC CRYSTAL SURFACE ENHANCED UPCONVERSION EMISSION OF YF3:Yb3+, Er3+ NANOPARTICLES

    NASA Astrophysics Data System (ADS)

    Shao, Bo; Yang, Zhengwen; Li, Jun; Liao, Jiayan; Lai, Shenfeng; Qiu, Jianbei; Song, Zhiguo; Yang, Yong; Zhou, Dacheng

    2015-11-01

    The opal photonic crystals made of polystyrene microspheres with 155, 230, 270 or 410 nm in diameter were used to enhance upconversion (UC) emission of YF3:Yb3+, Er3+ nanoparticles, respectively. The red or green UC emission of YF3:Yb3+, Er3+ nanoparticles can be selectively enhanced when the red or green UC emission wavelength overlapped with the photonic bandgaps of opals, which is attributed to Bragg reflection of photonic bandgap. In addition, when the 980 nm excitation light wavelength was in the region of the photonic bandgap, red and green UC emissions of YF3:Yb3+, Er3+ nanoparticles were enhanced due to the enhancement of excitation field.

  1. Quantum detector tomography of a single-photon frequency upconversion detection system.

    PubMed

    Ma, Jianhui; Chen, Xiuliang; Hu, Huiqin; Pan, Haifeng; Wu, E; Zeng, Heping

    2016-09-01

    We experimentally presented a full quantum detector tomography of a synchronously pumped infrared single-photon frequency upconversion detector. A maximum detection efficiency of 37.6% was achieved at the telecom wavelength of 1558 nm with a background noise about 1.0 × 10-3 counts/pulse. The corresponding internal quantum conversion efficiency reached as high as 84.4%. The detector was then systematically characterized at different pump powers to investigate the quantum decoherence behavior. Here the reconstructed positive operator valued measure elements were equivalently illustrated with the Wigner function formalism, where the quantum feature of the detector is manifested by the presence of negative values of the Wigner function. In our experiment, pronounced negativities were attained due to the high detection efficiency and low background noise, explicitly showing the quantum feature of the detector. Such quantum detector could be useful in optical quantum state engineering, quantum information processing and communication. PMID:27607700

  2. Construction of an upconversion nanoprobe with few-atom silver nanoclusters as the energy acceptor.

    PubMed

    Xiao, Yan; Zeng, Lingyu; Xia, Tian; Wu, Zhengjun; Liu, Zhihong

    2015-04-27

    Herein we report that few-atom silver nanoclusters (Ag NCs) can be effective energy acceptors for upconversion phosphors (UCPs). A luminescence resonance energy transfer (LRET) probe for biothiols was constructed by decorating UCPs with dithiol-stabilized Ag NCs. Owing to the unique properties of ultrasmall NCs, properties which bridge the gap between those of small molecules and those of nanoparticles, the use of approximately 1.9 nm Ag NCs as energy acceptors endows the probe with high energy-transfer efficiency, good biocompatibility, and flexibility. The UCP-Ag NC nanoprobe enables rapid and robust target assay in solutions. It was also uploaded into living cells and used to detect intracellular biothiol levels with high discrimination. Moreover, the probe shows transportability in vivo and can be used for tissue imaging. The facile growth of few-atom metal NCs on diverse templates may enable the development of various nanoprobes combining UCPs and metal NCs.

  3. Ultraviolet and white photon avalanche upconversion in Ho{sup 3+}-doped nanophase glass ceramics

    SciTech Connect

    Lahoz, F.; Martin, I.R.; Calvilla-Quintero, J.M.

    2005-01-31

    Ho{sup 3+}-doped fluoride nanophase glass ceramics have been synthesized from silica-based oxyfluoride glass. An intense white emission light is observed by the naked eye under near infrared excitation at 750 nm. This visible upconversion is due to three strong emission bands in the primary color components, red, green, and blue. Besides, ultraviolet signals are also recorded upon the same excitation wavelength. The excitation mechanism of both the ultraviolet and the visible emissions is a photon avalanche process with a relatively low pump power threshold at about 20 mW. The total upconverted emission intensity has been estimated to increase by about a factor of 20 in the glass ceramic compared to the precursor glass, in which an avalanche type mechanism is not generated.

  4. Nanopatterned PMMA-Yb:Er/Tm:Lu2O3 composites with visible upconversion emissions

    NASA Astrophysics Data System (ADS)

    Han, X.; Maiz, J.; Mijangos, C.; Zaldo, C.

    2014-05-01

    Nanopillars, nanotubes and nanofibers of transparent polymethyl methacrylate (PMMA) polymer with Yb:Ln:Lu2O3 (Ln = Er or Tm) nanoparticles (NPs) (≈30-35 nm average size) have been prepared by infiltration of anodized aluminum oxide hexagonally nanopatterned templates. The outer diameter of these nanostructures is in the 330-400 nm range, with lengths up to 50 μm and a period distance of 430 nm. These nanostructures show visible upconversion (UC) emissions under excitation with 978 nm light. The steady state temperature of the polymer nanostructures is optically evidenced by the Er3+ UC emission and optically controlled around the PMMA glass transition temperature by the excitation light, introducing a new method for NP storage in a solid and potential optically induced particle release. Full color emission is shown in tridoped (Yb:Er:Tm) samples.

  5. Hybrid Molecule-Nanocrystal Photon Upconversion Across the Visible and Near-Infrared.

    PubMed

    Huang, Zhiyuan; Li, Xin; Mahboub, Melika; Hanson, Kerry M; Nichols, Valerie M; Le, Hoang; Tang, Ming L; Bardeen, Christopher J

    2015-08-12

    The ability to upconvert two low energy photons into one high energy photon has potential applications in solar energy, biological imaging, and data storage. In this Letter, CdSe and PbSe semiconductor nanocrystals are combined with molecular emitters (diphenylanthracene and rubrene) to upconvert photons in both the visible and the near-infrared spectral regions. Absorption of low energy photons by the nanocrystals is followed by energy transfer to the molecular triplet states, which then undergo triplet-triplet annihilation to create high energy singlet states that emit upconverted light. By using conjugated organic ligands on the CdSe nanocrystals to form an energy cascade, the upconversion process could be enhanced by up to 3 orders of magnitude. The use of different combinations of nanocrystals and emitters shows that this platform has great flexibility in the choice of both excitation and emission wavelengths.

  6. Quantum detector tomography of a single-photon frequency upconversion detection system.

    PubMed

    Ma, Jianhui; Chen, Xiuliang; Hu, Huiqin; Pan, Haifeng; Wu, E; Zeng, Heping

    2016-09-01

    We experimentally presented a full quantum detector tomography of a synchronously pumped infrared single-photon frequency upconversion detector. A maximum detection efficiency of 37.6% was achieved at the telecom wavelength of 1558 nm with a background noise about 1.0 × 10-3 counts/pulse. The corresponding internal quantum conversion efficiency reached as high as 84.4%. The detector was then systematically characterized at different pump powers to investigate the quantum decoherence behavior. Here the reconstructed positive operator valued measure elements were equivalently illustrated with the Wigner function formalism, where the quantum feature of the detector is manifested by the presence of negative values of the Wigner function. In our experiment, pronounced negativities were attained due to the high detection efficiency and low background noise, explicitly showing the quantum feature of the detector. Such quantum detector could be useful in optical quantum state engineering, quantum information processing and communication.

  7. Upconversion of lower-hybrid waves by gyrating ion beams in a plasma

    NASA Technical Reports Server (NTRS)

    Sharma, O. P.; Patel, V. L.

    1985-01-01

    A gyrating ion beam, with ring shape distribution in velocity space, supports negative energy modes near the harmonics of beam gyrofrequency. An investigation of the nonlinear interaction of high-frequency lower-hybrid waves with the negative energy beam cyclotron mode is made. A nonlinear dispersion relation is derived for the coupled modes. It is shown that a gyrating ion beam frequency upconverts the lower-hybrid waves separated by harmonics of the beam gyrofrequency. This process of upconversion may thus provide a tool for the diagnostics of the gyrating ion beams. The process may also be important in the saturation of lower-hybrid waves observed in the auroral zone S3-3 satellite data.

  8. Hybrid Molecule-Nanocrystal Photon Upconversion Across the Visible and Near-Infrared.

    PubMed

    Huang, Zhiyuan; Li, Xin; Mahboub, Melika; Hanson, Kerry M; Nichols, Valerie M; Le, Hoang; Tang, Ming L; Bardeen, Christopher J

    2015-08-12

    The ability to upconvert two low energy photons into one high energy photon has potential applications in solar energy, biological imaging, and data storage. In this Letter, CdSe and PbSe semiconductor nanocrystals are combined with molecular emitters (diphenylanthracene and rubrene) to upconvert photons in both the visible and the near-infrared spectral regions. Absorption of low energy photons by the nanocrystals is followed by energy transfer to the molecular triplet states, which then undergo triplet-triplet annihilation to create high energy singlet states that emit upconverted light. By using conjugated organic ligands on the CdSe nanocrystals to form an energy cascade, the upconversion process could be enhanced by up to 3 orders of magnitude. The use of different combinations of nanocrystals and emitters shows that this platform has great flexibility in the choice of both excitation and emission wavelengths. PMID:26161875

  9. Heterogeneous core/shell fluoride nanocrystals with enhanced upconversion photoluminescence for in vivo bioimaging.

    PubMed

    Hao, Shuwei; Yang, Liming; Qiu, Hailong; Fan, Rongwei; Yang, Chunhui; Chen, Guanying

    2015-06-28

    We report on heterogeneous core/shell CaF2:Yb(3+)/Ho(3+)@NaGdF4 nanocrystals of 17 nm with efficient upconversion (UC) photoluminescence (PL) for in vivo bioimaging. Monodisperse core/shell nanostructures were synthesized using a seed-mediated growth process involving two quite different approaches of liquid-solid-solution and thermal decomposition. They exhibit green emission with a sharp band around 540 nm when excited at ∼980 nm, which is about 39 times brighter than the core CaF2:Yb(3+)/Ho(3+) nanoparticles. PL decays at 540 nm revealed that such an enhancement arises from efficient suppression of surface-related deactivation from the core nanocrystals. In vivo bioimaging employing water-dispersed core/shell nanoparticles displayed high contrast against the background. PMID:26035440

  10. Multifunctional nanoparticles for upconversion luminescence/MR multimodal imaging and magnetically targeted photothermal therapy.

    PubMed

    Cheng, Liang; Yang, Kai; Li, Yonggang; Zeng, Xiao; Shao, Mingwang; Lee, Shuit-Tong; Liu, Zhuang

    2012-03-01

    Theranostics, the combination of diagnostics and therapies, has become a new concept in the battles with various major diseases such as cancer. Herein, we develop multifunctional nanoparticles (MFNPs) with highly integrated functionalities including upconversion luminescence, superparamagnetism, and strong optical absorption in the near-infrared (NIR) region with high photostability. In vivo dual modal optical/magnetic resonance imaging of mice uncovers that by placing a magnet nearby the tumor, MFNPs tend to migrate toward the tumor after intravenous injection and show high tumor accumulation, which is ~8 folds higher than that without magnetic targeting. NIR laser irradiation is then applied to the tumors grown on MFNP-injected mice under magnetic tumor-targeting, obtaining an outstanding photothermal therapeutic efficacy with 100% of tumor elimination in a murine breast cancer model. We present here a strategy for multimodal imaging-guided, magnetically targeted physical cancer therapy and highlight the promise of using multifunctional nanostructures for cancer theranostics.

  11. Frequency Up-Conversion to the Vacuum Ultra-Violet in Coherently Prepared Media

    NASA Astrophysics Data System (ADS)

    Marangos, J. P.; Kuçukkara, I.; Anscombe, M.

    In this contribution we discuss recent work that has demonstrated that electromagnetically induced transparency (EIT) can greatly increase the intensity of coherent vacuum ultra-violet (VUV) radiation (at wavelengths shorter than 130nm) generated in resonant four-wave mixing schemes. We will start by introducing the basic concept of EIT enhanced resonant four-wave mixing, comparing it briefly with other coherently enhanced non-linear frequency up-conversion schemes. Experiments proving this concept in atomic hydrogen in the mid-1990's will be summarised. Our own recent work on EIT enhanced four-wave mixing in Kr will be presented and recent results demonstrating high conversion efficiencies into the VUV, and the limits placed on this process at high density-length products, will be discussed.

  12. Tuning upconversion through a sensitizer/activator-isolated NaYF4 core/shell structure

    NASA Astrophysics Data System (ADS)

    Ye, Shuai; Chen, Guanying; Shao, Wei; Qu, Junle; Prasad, Paras N.

    2015-02-01

    The ability to tune the emission color of upconversion nanoparticles (UCNPs) will greatly enhance the scope of their applications, ranging from infrared solar cells to volumetric multiplexed bioimaging. Conventional methods to tune upconversion are to vary the type and/or the concentration of doped rare-earth ions in these nanoparticle formulations. Here, we introduce a different approach to vary the emission colors of the frequently used sensitizer/activator pairs of Yb3+/RE3+ (RE = Ho, Er, Tm) via utilization of a sensitizer/activator-isolated NaYF4 core-shell structure. We show that the typical green, yellow, and blue luminescent colors from Yb3+/Ho3+-, Yb3+/Er3+-, and Yb3+/Tm3+-co-doped NaYF4 UCNPs can be converted into the quasi-white, green, and pink blue, when corresponding core-shell structures of NaYF4:Yb3+ @NaYF4:Ho3+, NaYF4:Yb3+ @NaYF4:Er3+ and NaYF4:Yb3+ @NaYF4:Tm3+ are built. Time-resolved spectra indicate that decay lifetimes of the emission bands from the sensitizer/activator-isolated core-shell structure significantly vary from that of the sensitizer/activator-codoped NaYF4 UCNPs, verifying the strain-induced modulation of emission channels in the core-shell structure. These sensitizer-activator-isolated core-shell UCNPs have implications for a range of biophotonic or photonic applications.The ability to tune the emission color of upconversion nanoparticles (UCNPs) will greatly enhance the scope of their applications, ranging from infrared solar cells to volumetric multiplexed bioimaging. Conventional methods to tune upconversion are to vary the type and/or the concentration of doped rare-earth ions in these nanoparticle formulations. Here, we introduce a different approach to vary the emission colors of the frequently used sensitizer/activator pairs of Yb3+/RE3+ (RE = Ho, Er, Tm) via utilization of a sensitizer/activator-isolated NaYF4 core-shell structure. We show that the typical green, yellow, and blue luminescent colors from Yb3+/Ho3+-, Yb3+/Er

  13. Nd(3+)-sensitized upconversion nanophosphors: efficient in vivo bioimaging probes with minimized heating effect.

    PubMed

    Wang, Ye-Fu; Liu, Gao-Yuan; Sun, Ling-Dong; Xiao, Jia-Wen; Zhou, Jia-Cai; Yan, Chun-Hua

    2013-08-27

    Upconversion (UC) process in lanthanide-doped nanomaterials has attracted great research interest for its extensive biological applications in vitro and in vivo, benefiting from the high tissue penetration depth of near-infrared excitation light and low autofluorescence background. However, the 980 nm laser, typically used to trigger the Yb(3+)-sensitized UC process, is strongly absorbed by water in biological structures and could cause severe overheating effect. In this article, we report the extension of the UC excitation spectrum to shorter wavelengths, where water has lower absorption. This is realized by further introducing Nd(3+) as the sensitizer and by building a core/shell structure to ensure successive Nd(3+) → Yb(3+) → activator energy transfer. The efficacy of this Nd(3+)-sensitized UC process is demonstrated in in vivo imaging, and the results confirmed that the laser-induced local overheating effect is greatly minimized.

  14. Near-infrared photocatalysts of BiVO4/CaF2:Er3+, Tm3+, Yb3+ with enhanced upconversion properties

    NASA Astrophysics Data System (ADS)

    Huang, Shouqiang; Zhu, Nanwen; Lou, Ziyang; Gu, Lin; Miao, Chen; Yuan, Haiping; Shan, Aidang

    2014-01-01

    Upconversion photocatalysts have the potential to absorb the near-infrared (NIR) light in solar energy and improve the photocatalytic performance. A hierarchical upconversion photocatalyst of BiVO4 (BVO)/CaF2:Er3+, Tm3+, Yb3+ (CF) combined with the narrow-band semiconductor of BVO and the luminescence agent of CF to enhance upconversion properties was synthesized via the hydrothermal method. The CF particles were deposited homogeneously on the surface of the BVO/CF composite with regular dendritic structure, which led to efficient upconversion emissions. The upconversion emission intensity of the BVO/CF composite was 8 times higher than that of pure CF, through tailoring the crystal symmetry of lanthanide ions by Bi3+ ions. The upconverted ultraviolet (361 and 379 nm), violet (408 nm), and blue (485 nm) light was able to excite BVO for photocatalysis in BVO/CF under NIR irradiation, which improved the degradation rate of methyl orange (MO).Upconversion photocatalysts have the potential to absorb the near-infrared (NIR) light in solar energy and improve the photocatalytic performance. A hierarchical upconversion photocatalyst of BiVO4 (BVO)/CaF2:Er3+, Tm3+, Yb3+ (CF) combined with the narrow-band semiconductor of BVO and the luminescence agent of CF to enhance upconversion properties was synthesized via the hydrothermal method. The CF particles were deposited homogeneously on the surface of the BVO/CF composite with regular dendritic structure, which led to efficient upconversion emissions. The upconversion emission intensity of the BVO/CF composite was 8 times higher than that of pure CF, through tailoring the crystal symmetry of lanthanide ions by Bi3+ ions. The upconverted ultraviolet (361 and 379 nm), violet (408 nm), and blue (485 nm) light was able to excite BVO for photocatalysis in BVO/CF under NIR irradiation, which improved the degradation rate of methyl orange (MO). Electronic supplementary information (ESI) available: Additional tables and figures. See

  15. Lanthanide-doped upconversion nanoparticles electrostatically coupled with photosensitizers for near-infrared-triggered photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Wang, Meng; Chen, Zhuo; Zheng, Wei; Zhu, Haomiao; Lu, Shan; Ma, En; Tu, Datao; Zhou, Shanyong; Huang, Mingdong; Chen, Xueyuan

    2014-06-01

    Lanthanide-doped upconversion nanoparticles (UCNPs) have recently shown great promise in photodynamic therapy (PDT). Herein, we report a facile strategy to fabricate an efficient NIR-triggered PDT system based on LiYF4:Yb/Er UCNPs coupled with a photosensitizer of a β-carboxyphthalocyanine zinc (ZnPc-COOH) molecule via direct electrostatic interaction. Due to the close proximity between UCNPs and ZnPc-COOH, we achieved a high energy transfer efficiency of 96.3% from UCNPs to ZnPc-COOH, which facilitates a large production of cytotoxic singlet oxygen and thus an enhanced PDT efficacy. Furthermore, we demonstrate the high efficacy of such a NIR-triggered PDT agent for the inhibition of tumor growth both in vitro and in vivo, thereby revealing the great potential of the UCNP-based PDT systems as noninvasive NIR-triggered PDT agents for deep cancer therapy.Lanthanide-doped upconversion nanoparticles (UCNPs) have recently shown great promise in photodynamic therapy (PDT). Herein, we report a facile strategy to fabricate an efficient NIR-triggered PDT system based on LiYF4:Yb/Er UCNPs coupled with a photosensitizer of a β-carboxyphthalocyanine zinc (ZnPc-COOH) molecule via direct electrostatic interaction. Due to the close proximity between UCNPs and ZnPc-COOH, we achieved a high energy transfer efficiency of 96.3% from UCNPs to ZnPc-COOH, which facilitates a large production of cytotoxic singlet oxygen and thus an enhanced PDT efficacy. Furthermore, we demonstrate the high efficacy of such a NIR-triggered PDT agent for the inhibition of tumor growth both in vitro and in vivo, thereby revealing the great potential of the UCNP-based PDT systems as noninvasive NIR-triggered PDT agents for deep cancer therapy. Electronic supplementary information (ESI) available: Tables S1 and S2 and Fig. S1-S13. See DOI: 10.1039/c4nr01826e

  16. Architecture, development and implementation of a SWIR to visible integrated up-conversion imaging device

    NASA Astrophysics Data System (ADS)

    Sarusi, Gabby; Templeman, Tzvi; Hechster, Elad; Nissim, Nimrod; Vitenberg, Vladimir; Maman, Nitzan; Tal, Amir; Solodar, Assi; Makov, Guy; Abdulhalim, Ibrahim; Visoly-Fisher, Iris; Golan, Yuval

    2016-04-01

    A new concept of short wavelength infrared (SWIR) to visible upconversion integrated imaging device is proposed, modeled and some initial measured results are presented. The device is a hybrid inorganic-organic device that comprises six nano-metric scale sub-layers grown on n-type GaAs substrates. The first layer is a ~300nm thick PbSe nano-columnar absorber layer grown in (111) orientation to the substrate plan (100), with a diameter of 8- 10nm and therefore exhibit quantum confinement effects parallel to the substrate and bulk properties perpendicular to it. The advantage of this structure is the high oscillator strength and hence absorption to incoming SWIR photons while maintaining the high bulk mobility of photo-excited charges along the columns. The top of the PbSe absorber layer is coated with 20nm thick metal layer that serves as a dual sided mirror, as well as a potentially surface plasmon enhanced absorption in the PbSe nano-columns layer. The photo-excited charges (holes and electrons in opposite directions) are drifted under an external applied field to the OLED section (that is composed of a hole transport layer, an emission layer and an electron transport layer) where they recombine with injected electron from the transparent cathode and emit visible light through this cathode. Due to the high absorption and enhanced transport properties this architecture has the potential of high quantum efficiency, low cost and easy implementation in any optical system. As a bench-mark, alternative concept where InGaAs/InP heterojunction couple to liquid crystal optical spatial light modulator (OSLM) structure was built that shows a full upconversion to visible of 1550nm laser light.

  17. An instrument to measure mechanical up-conversion phenomena in metals in the elastic regime.

    PubMed

    Vajente, G; Quintero, E A; Ni, X; Arai, K; Gustafson, E K; Robertson, N A; Sanchez, E J; Greer, J R; Adhikari, R X

    2016-06-01

    Crystalline materials, such as metals, are known to exhibit deviation from a simple linear relation between strain and stress when the latter exceeds the yield stress. In addition, it has been shown that metals respond to varying external stress in a discontinuous way in this regime, exhibiting discrete releases of energy. This crackling noise has been extensively studied both experimentally and theoretically when the metals are operating in the plastic regime. In our study, we focus on the behavior of metals in the elastic regime, where the stresses are well below the yield stress. We describe an instrument that aims to characterize non-linear mechanical noise in metals when stressed in the elastic regime. In macroscopic systems, this phenomenon is expected to manifest as a non-stationary noise modulated by external disturbances applied to the material, a form of mechanical up-conversion of noise. The main motivation for this work is for the case of maraging steel components (cantilevers and wires) in the suspension systems of terrestrial gravitational wave detectors. Such instruments are planned to reach very ambitious displacement sensitivities, and therefore mechanical noise in the cantilevers could prove to be a limiting factor for the detectors' final sensitivities, mainly due to non-linear up-conversion of low frequency residual seismic motion to the frequencies of interest for the gravitational wave observations. We describe here the experimental setup, with a target sensitivity of 10(-15) m/Hz in the frequency range of 10-1000 Hz, a simple phenomenological model of the non-linear mechanical noise, and the analysis method that is inspired by this model. PMID:27370497

  18. An instrument to measure mechanical up-conversion phenomena in metals in the elastic regime

    NASA Astrophysics Data System (ADS)

    Vajente, G.; Quintero, E. A.; Ni, X.; Arai, K.; Gustafson, E. K.; Robertson, N. A.; Sanchez, E. J.; Greer, J. R.; Adhikari, R. X.

    2016-06-01

    Crystalline materials, such as metals, are known to exhibit deviation from a simple linear relation between strain and stress when the latter exceeds the yield stress. In addition, it has been shown that metals respond to varying external stress in a discontinuous way in this regime, exhibiting discrete releases of energy. This crackling noise has been extensively studied both experimentally and theoretically when the metals are operating in the plastic regime. In our study, we focus on the behavior of metals in the elastic regime, where the stresses are well below the yield stress. We describe an instrument that aims to characterize non-linear mechanical noise in metals when stressed in the elastic regime. In macroscopic systems, this phenomenon is expected to manifest as a non-stationary noise modulated by external disturbances applied to the material, a form of mechanical up-conversion of noise. The main motivation for this work is for the case of maraging steel components (cantilevers and wires) in the suspension systems of terrestrial gravitational wave detectors. Such instruments are planned to reach very ambitious displacement sensitivities, and therefore mechanical noise in the cantilevers could prove to be a limiting factor for the detectors' final sensitivities, mainly due to non-linear up-conversion of low frequency residual seismic motion to the frequencies of interest for the gravitational wave observations. We describe here the experimental setup, with a target sensitivity of 10-15 m/ √{ Hz } in the frequency range of 10-1000 Hz, a simple phenomenological model of the non-linear mechanical noise, and the analysis method that is inspired by this model.

  19. An instrument to measure mechanical up-conversion phenomena in metals in the elastic regime.

    PubMed

    Vajente, G; Quintero, E A; Ni, X; Arai, K; Gustafson, E K; Robertson, N A; Sanchez, E J; Greer, J R; Adhikari, R X

    2016-06-01

    Crystalline materials, such as metals, are known to exhibit deviation from a simple linear relation between strain and stress when the latter exceeds the yield stress. In addition, it has been shown that metals respond to varying external stress in a discontinuous way in this regime, exhibiting discrete releases of energy. This crackling noise has been extensively studied both experimentally and theoretically when the metals are operating in the plastic regime. In our study, we focus on the behavior of metals in the elastic regime, where the stresses are well below the yield stress. We describe an instrument that aims to characterize non-linear mechanical noise in metals when stressed in the elastic regime. In macroscopic systems, this phenomenon is expected to manifest as a non-stationary noise modulated by external disturbances applied to the material, a form of mechanical up-conversion of noise. The main motivation for this work is for the case of maraging steel components (cantilevers and wires) in the suspension systems of terrestrial gravitational wave detectors. Such instruments are planned to reach very ambitious displacement sensitivities, and therefore mechanical noise in the cantilevers could prove to be a limiting factor for the detectors' final sensitivities, mainly due to non-linear up-conversion of low frequency residual seismic motion to the frequencies of interest for the gravitational wave observations. We describe here the experimental setup, with a target sensitivity of 10(-15) m/Hz in the frequency range of 10-1000 Hz, a simple phenomenological model of the non-linear mechanical noise, and the analysis method that is inspired by this model.

  20. Cucurbit[n]uril-capped upconversion nanoparticles as highly emissive scaffolds for energy acceptors

    NASA Astrophysics Data System (ADS)

    Francés-Soriano, Laura; González-Béjar, María; Pérez-Prieto, Julia

    2015-03-01

    Spontaneous adsorption of cucurbit[n]uril CB[n] (n = 6, 7, and 8) on the surface of naked upconversion nanoparticles (UCNPs), in particular, NaYF4:Er3+(2%),Yb3+(18%) gave rise to UCNP@CB[n] exclusion complexes. These complexes proved to be highly stable as well as highly emissive under near-infrared excitation. By using two tricyclic basic dyes (specifically, methylene blue and pyronin Y) as a proof of concept, we demonstrate that the UCNP@CB[n] (n = 6, 7) nanohybrids can form exclusion complexes with this type of dyes via the CB carbonyl free portal, i.e., UCNP@CB@dye hybrids, thus making it possible to locate a high concentration of the dyes close to the UCNP and, consequently, leading to efficient energy transfer from the UCNP to the dye.Spontaneous adsorption of cucurbit[n]uril CB[n] (n = 6, 7, and 8) on the surface of naked upconversion nanoparticles (UCNPs), in particular, NaYF4:Er3+(2%),Yb3+(18%) gave rise to UCNP@CB[n] exclusion complexes. These complexes proved to be highly stable as well as highly emissive under near-infrared excitation. By using two tricyclic basic dyes (specifically, methylene blue and pyronin Y) as a proof of concept, we demonstrate that the UCNP@CB[n] (n = 6, 7) nanohybrids can form exclusion complexes with this type of dyes via the CB carbonyl free portal, i.e., UCNP@CB@dye hybrids, thus making it possible to locate a high concentration of the dyes close to the UCNP and, consequently, leading to efficient energy transfer from the UCNP to the dye. Electronic supplementary information (ESI) available: Experimental methods, TEM images, EDX, XRD, absorption and emission spectra, 1H-NMR. See DOI: 10.1039/c5nr00295h

  1. Room temperature terahertz wave imaging at 60 fps by frequency up-conversion in DAST crystal

    NASA Astrophysics Data System (ADS)

    Fan, Shuzhen; Qi, Feng; Notake, Takashi; Nawata, Kouji; Matsukawa, Takeshi; Takida, Yuma; Minamide, Hiroaki

    2014-02-01

    Terahertz imaging has attracted a lot of interests for more than 10 years. But real time, high sensitive, low cost THz imaging in room temperature, which is widely needed by fields such as biology, biomedicine and homeland security, has not been fully developed yet. A lot of approaches have been reported on electro-optic (E-O) imaging and THz focal plane arrays with photoconductive antenna or micro-bolometer integrated. In this paper, we report high sensitive realtime THz image at 60 frames per second (fps) employing a commercial infrared camera, using nonlinear optical frequency up-conversion technology. In this system, a flash-lamp pumped nanosecond pulse green laser is used to pump two optical parametric oscillator systems with potassium titanyl phosphate crystals (KTP-OPO). One system with dual KTP crystals is used to generate infrared laser for the pumping of THz difference frequency generation (DFG) in a 4- Dimethylamino-N-Methyl-4-Stilbazolium Tosylate (DAST) crystal. The other one is for generation of pumping laser for THz frequency up-conversion in a second DAST crystal. The THz frequency can be tuned continuously from a few THz to less than 30 THz by controlling the angle of KTP crystals. The frequency up-converted image in infrared region is recorded by a commercial infrared camera working at 60 Hz. Images and videos are presented to show the feasibility of this technique and the real-time ability. Comparison with a general micro-bolometer THz camera shows the high sensitivity of this technique.

  2. Submicron polyacrolein particles in situ embedded with upconversion nanoparticles for bioassay

    NASA Astrophysics Data System (ADS)

    Generalova, A. N.; Kochneva, I. K.; Khaydukov, E. V.; Semchishen, V. A.; Guller, A. E.; Nechaev, A. V.; Shekhter, A. B.; Zubov, V. P.; Zvyagin, A. V.; Deyev, S. M.

    2015-01-01

    We report a new surface modification approach of upconversion nanoparticles (UCNPs) structured as inorganic hosts NaYF4 codoped with Yb3+ and Er3+ based on their encapsulation in a two-stage process of precipitation polymerization of acrolein under alkaline conditions in the presence of UCNPs. The use of tetramethylammonium hydroxide both as an initiator of acrolein polymerization and as an agent for UCNP hydrophilization made it possible to increase the polyacrolein yield up to 90%. This approach enabled the facile, lossless embedment of UCNPs into the polymer particles suitable for bioassay. These particles are readily dispersible in aqueous and physiological buffers, exhibiting excellent photoluminescence properties, chemical stability, and also allow the control of particle diameters. The feasibility of the as-produced photoluminescent polymer particles mean-sized 260 nm for in vivo optical whole-animal imaging was also demonstrated using a home-built epi-luminescence imaging system.We report a new surface modification approach of upconversion nanoparticles (UCNPs) structured as inorganic hosts NaYF4 codoped with Yb3+ and Er3+ based on their encapsulation in a two-stage process of precipitation polymerization of acrolein under alkaline conditions in the presence of UCNPs. The use of tetramethylammonium hydroxide both as an initiator of acrolein polymerization and as an agent for UCNP hydrophilization made it possible to increase the polyacrolein yield up to 90%. This approach enabled the facile, lossless embedment of UCNPs into the polymer particles suitable for bioassay. These particles are readily dispersible in aqueous and physiological buffers, exhibiting excellent photoluminescence properties, chemical stability, and also allow the control of particle diameters. The feasibility of the as-produced photoluminescent polymer particles mean-sized 260 nm for in vivo optical whole-animal imaging was also demonstrated using a home-built epi-luminescence imaging

  3. Light-activated endosomal escape using upconversion nanoparticles for enhanced delivery of drugs

    NASA Astrophysics Data System (ADS)

    Gnanasammandhan, Muthu Kumara; Bansal, Akshaya; Zhang, Yong

    2013-02-01

    Nanoparticle-based delivery of drugs has gained a lot of prominence recently but the main problem hampering efficient delivery of payload is the clearing or degradation of nanoparticles by endosomes. Various strategies have been used to overcome this issue and one such effective solution is Photochemical Internalization (PCI). This technique involves the activation of certain photosensitizing compounds by light, which accumulate specifically in the membranes of endocytic vesicles. The activated photosensitizers induce the formation of reactive oxygen species which in turn induces localized disruption of endosomal membranes. But the drawback of this technique is that it needs blue light for activation and hence confined to be used only in in-vitro systems due to the poor tissue penetration of blue light. Here, we report the use of Upconversion nanoparticles (UCNs) as a transducer for activation of the photosensitizer, TPPS 2a. NIR light has good tissue penetrating ability and thus enables PCI in greater depths. Highly monodisperse, uniformly-sized, sub-100 nm, biocompatible upconversion nanoparticles were synthesized with a mesoporous silica coating. These UCNs activated TPPS 2a efficiently in solution and in cells. Paclitaxel, an anti-cancer drug was used as a model drug and was loaded into the mesoporous silica coating. B16F0 cells transfected with drug-loaded UCNs and irradiated with NIR showed significantly higher nanoparticle uptake and in turn higher cell death caused by the delivered drug. This technique can be used to enhance the delivery of any therapeutic molecule and thus increase the therapeutic efficiency considerably.

  4. Tuning upconversion through a sensitizer/activator-isolated NaYF₄ core/shell structure.

    PubMed

    Ye, Shuai; Chen, Guanying; Shao, Wei; Qu, Junle; Prasad, Paras N

    2015-03-01

    The ability to tune the emission color of upconversion nanoparticles (UCNPs) will greatly enhance the scope of their applications, ranging from infrared solar cells to volumetric multiplexed bioimaging. Conventional methods to tune upconversion are to vary the type and/or the concentration of doped rare-earth ions in these nanoparticle formulations. Here, we introduce a different approach to vary the emission colors of the frequently used sensitizer/activator pairs of Yb(3+)/RE(3+) (RE = Ho, Er, Tm) via utilization of a sensitizer/activator-isolated NaYF4 core-shell structure. We show that the typical green, yellow, and blue luminescent colors from Yb(3+)/Ho(3+)-, Yb(3+)/Er(3+)-, and Yb(3+)/Tm(3+)-co-doped NaYF4 UCNPs can be converted into the quasi-white, green, and pink blue, when corresponding core-shell structures of NaYF4:Yb(3+) @NaYF4:Ho(3+), NaYF4:Yb(3+) @NaYF4:Er(3+) and NaYF4:Yb(3+) @NaYF4:Tm(3+) are built. Time-resolved spectra indicate that decay lifetimes of the emission bands from the sensitizer/activator-isolated core-shell structure significantly vary from that of the sensitizer/activator-codoped NaYF4 UCNPs, verifying the strain-induced modulation of emission channels in the core-shell structure. These sensitizer-activator-isolated core-shell UCNPs have implications for a range of biophotonic or photonic applications.

  5. Tuning Upconversion Emission of β-NaGdF4:Yb+/Ho3+ Nanorods Through Yb3+.

    PubMed

    Gao, Fangqi; Gao, Wei; Wang, Ruibo; Yan, Longxiang; Li, Jinping; Zheng, Hairong

    2016-04-01

    Yb3+/Ho3+ doped hexagonal NaGdF4 nanocrystals are synthesized through solvothermal method, for which pure hexagonal phased nanorods are presented. The concentration influence of Yb3+ ions on the sample morphology and fluorescence emission of Ho3+ is investigated. It is found that the sample size is changed from 25 nm to 125 nm and the upconversion emission is tuned from green to yellow when the concentration of Yb3+ ions is increased from 5.0 mol% to 50.0 mol%. The possible upconversion mechanism and the improvement of crystallinity are carefully investigated. It is suggested that the cross-relaxation process between Ho3+ ions promotes the red emission and quenches the green emission. PMID:27451703

  6. Measurement of quantum yield of up-conversion Luminescence in Er(3+)-doped nano-glass-ceramics.

    PubMed

    Rodríguez, V D; Tikhomirov, V K; Méndez-Ramos, J; del-Castillo, J; Görller-Walrand, C

    2009-03-01

    A measurement of quantum yield of up-conversion luminescence has been done for the Er(3+)-doped transparent oxyfluoride glass-ceramics 32(SiO,)9(AlO1.5)31.5(CdF2)18.5(PbF2)5.5(ZnF2): 3.5(ErF3) mol%, where most of Er3+ dopants partition in 8 nm diameter nano-crystals Er10Pb25F65. The yield was found by newly proposed method using the pump power dependence of the resonant luminescence. The result of the measurement points out that a theoretical maximum of 50% may be reached for the up-conversion luminescence yield in this material. This high yield is shown to be due to low phonon energy and short inter-dopant distances in the nano-crystals.

  7. Localization induced intense red upconversion luminescence in monodispersed K3ZrF7:Yb3+/Er3+ nanocrystals

    NASA Astrophysics Data System (ADS)

    Luo, Wenqin; Wu, Haiyan; Li, Bin

    2016-08-01

    There are increasing demands for upconversion (UC) nanocrystals since they are found to have important applications in the field of bio-imaging. Herein, novel monodispersed Yb3+/Er3+ co-doped K3ZrF7 nanocrystals with tunable sizes of 6-30 nm were prepared by high temperature co-precipitation method. Intense UC emission of Er3+ with large red to green ratio was obtained under the excitation of 980 nm-laser due to the cation localization effects. The UC luminescent lifetimes of 4S3/2 and 4F9/2 were determined to be 0.137 and 0.217 ms, respectively. At last, the possible upconversion mechanism was proposed basing on the pump power dependent UC luminescence experiments.

  8. A novel contrast agent with rare earth-doped up-conversion luminescence and Gd-DTPA magnetic resonance properties

    NASA Astrophysics Data System (ADS)

    Lu, Qing; Wei, Daixu; Cheng, Jiejun; Xu, Jianrong; Zhu, Jun

    2012-08-01

    The magnetic-luminescent multifunctional nanoparticles based on Gd-DTPA and NaYF4:Yb, Er were successfully synthesized by the conjugation of activated DTPA and silica-coated/surface-aminolated NaYF4:Yb, Er nanoparticles through EDC/NHS coupling chemistry. The as-prepared products were characterized by powder X-ray diffraction, transmission electron microscopy, dynamic light scattering, energy dispersive X-ray analysis, and fourier transform infrared spectrometry. The room-temperature upconversion luminescent spectra and T1-weighted maps of the obtained nanoparticles were carried out by 980 nm NIR light excitation and a 3T MR imaging scanner, respectively. The results indicated that the as-synthesized multifunctional nanoparticles with small size, highly solubility in water, and both high MR relaxivities and upconversion luminescence may have potential usage for MR imaging in future.

  9. Additives and solvents-induced phase and morphology modification of NaYF4 for improving up-conversion emission

    NASA Astrophysics Data System (ADS)

    Zhuang, Jianle; Yang, Xianfeng; Wang, Jing; Lei, Bingfu; Liu, Yingliang; Wu, Mingmei

    2016-01-01

    Both cubic and hexagonal NaYF4 were synthesized in different reaction systems via hydro/solvo-thermal route. The effects of reaction temperature, solvents, and additives on the synthesis of NaYF4 have been studied in detail. It has been shown that phase transformation from cubic NaYF4 to hexagonal NaYF4 always occurred. The sequence of the ability for inducing the phase transformation was ethanol>H2O>acetic acid. It is found that ethanol can not only facilitate the formation of hexagonal NaYF4 but also control the growth of the crystal. This is quite unusual for the growth of H-NaYF4. The up-conversion emission properties of Yb/Er co-doped NaYF4 have also been investigated and the results demonstrated some general principles for improving up-conversion emission.

  10. Targeted labeling of an early-stage tumor spheroid in a chorioallantoic membrane model with upconversion nanoparticles

    NASA Astrophysics Data System (ADS)

    Liu, Kai; Holz, Jasmin A.; Ding, Yadan; Liu, Xiaomin; Zhang, Youlin; Tu, Langping; Kong, Xianggui; Priem, Bram; Nadort, Annemarie; Lambrechts, Saskia A. G.; Aalders, Maurice C. G.; Buma, Wybren Jan; Liu, Yichun; Zhang, Hong

    2015-01-01

    In vivo detection of cancer at an early-stage, i.e. smaller than 2 mm, is a challenge in biomedicine. In this work target labeling of an early-stage tumor spheroid (~500 μm) is realized for the first time in a chick embryo chorioallantoic membrane (CAM) model with monoclonal antibody functionalized upconversion nanoparticles (UCNPs-mAb).In vivo detection of cancer at an early-stage, i.e. smaller than 2 mm, is a challenge in biomedicine. In this work target labeling of an early-stage tumor spheroid (~500 μm) is realized for the first time in a chick embryo chorioallantoic membrane (CAM) model with monoclonal antibody functionalized upconversion nanoparticles (UCNPs-mAb). Electronic supplementary information (ESI) available: Details of experimental procedures for the sample preparation and characterization, Chick CAM model, 3-D multicellular tumor spheroids, UCNPs circulating in CAM. See DOI: 10.1039/c4nr05638h

  11. MOLTEN SALT SYNTHESIS OF YF3:Yb3+/Ln3+(Ln = Er3+, Tm3+) MICROSHEETS WITH MULTICOLOR UPCONVERSION LUMINESCENCE

    NASA Astrophysics Data System (ADS)

    Ding, Mingye; Lu, Chunhua; Cao, Linhai; Ni, Yaru; Xu, Zhongzi

    2013-12-01

    In this paper, highly crystalline YF3:Yb3+/Ln3+(Ln = Er3+, Tm3+) microsheets were successfully synthesized by a surfactant-free molten salt method for the first time. The results indicated that the as-obtained samples belonged to orthorhombic system and exhibited microsheets morphology with side lengths of 30 to 80 μm and wall thickness from 1 to 1.5 μm. By changing the dopant's species (Ln3+), multicolor (yellow and blue) upconversion emission can be observed in YF3:Yb3+/Ln3+ microsheets under 980 nm laser diode (LD) excitation. The upconversion mechanisms in co-doping YF3 samples were analyzed in detail based on the emission spectra. Importantly, this approach not only proposes a new alternative in synthesizing such materials, but also opens the possibility to meet the increasing commercial demand.

  12. The Upconversion Luminescence Properties of Er3+/Tm3+, Yb3+-Codoped Cubic BaLiF3.

    PubMed

    Qiang, Qinping; Guo, Linna; Han, Lili; Wang, Yuhua

    2016-04-01

    Cubic BaLiF3 samples were prepared using a facile surfactant-assisted hydrothermal-microemulsion method. The samples were characterized by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The upconversion luminescence (UCL) properties of the Er3+/Tm3+, Yb3+- codoped BaLiF3 samples were measured under a 980 nm excitation wavelength. Moreover, the effects of varying the concentration of Li+ ions on the luminescence properties of Er3+, Yb3+ codoped BaLiF3 were also investigated. The Tm3+, Yb3+ codoped BaLiF3 samples displayed multi-color emissions. This behavior can be explained by the pump power dependence of the upconversion emissions and the energy levels diagram. PMID:27451695

  13. Enhanced green upconversion luminescence in Yb3+/Tb3+-codoped silica fiber based on glass phase-separated method

    NASA Astrophysics Data System (ADS)

    Chu, Yingbo; Yang, Yu; Liao, Lei; Wang, Yibo; Zhao, Nan; Wang, Zhao; Liu, Changbo; Peng, Jinggang; Li, Haiqin; Dai, Nengli; Li, Jinyan; Yang, Luyun

    2015-09-01

    We reported on an Yb3+/Tb3+-codoped silica fiber with a large fiber core prepared from nanoporous silica glass based on glass phase-separated method. The measured refractive index profile indicated an excellent homogeneity of the doped active fiber core. Intense green upconversion emission from Tb3+ centered at 543 nm was obtained in the Yb3+/Tb3+-codoped silica fiber under 976-nm excitation. It is suggested that the green upconversion emission is dominated by a two-photon absorption process. It is found that the Al3+ ions as a modifier can facilitate the energy transfer from Yb3+ to Tb3+ in the porous glass fiber. The energy transfer efficiency from Yb3+ to Tb3+ was calculated.

  14. Bi-stable frequency up-conversion piezoelectric energy harvester driven by non-contact magnetic repulsion

    NASA Astrophysics Data System (ADS)

    Tang, Q. C.; Yang, Y. L.; Li, Xinxin

    2011-12-01

    This paper presents miniaturized energy harvesters, where the frequency up-conversion technique is used to improve the bandwidth of vibration energy harvesters. The proposed and developed miniature piezoelectric energy harvester utilizes magnetic repulsion forces to achieve non-contact frequency up-conversion, thereby avoiding mechanical collision and wear for long-term working durability. A pair of piezoelectric resonant cantilevers is micro-fabricated to generate electric power. A simplified model involving linear oscillators and magnetic interaction is deployed to demonstrate the feasibility of the device design. A bench-top harvester has been fabricated and characterized, resulting in average power generation of over 10 µW within a broad frequency range of 10-22 Hz under 1g acceleration.

  15. Impact of high ytterbium(III) concentration in the shell on upconversion luminescence of core-shell nanocrystals.

    PubMed

    Lei, Lei; Chen, Daqin; Zhu, Wenjuan; Xu, Ju; Wang, Yuansheng

    2014-10-01

    After coating 20 Yb/2 Er:NaGdF4 core nanocrystals with a NaYbF4 shell, upconversion emission of the rare earth ions weakens. So far, the exact reason for this phenomenon is still unclear due to lack of the direct evidence. In this report, a core@shell@shell sandwich-like structure is designed and fabricated to investigate this phenomenon. We find that high Yb(3+) concentration in the shell has mainly two adverse impacts: it promotes not only the deleterious back energy transfer from Er(3+) in the core to Yb(3+) in the shell but also the energy transfer from Yb(3+) in the core to Yb(3+) in the shell. To obtain nanocrystals with high upconversion efficency, appropriate Yb(3+) concentration should be introduced into the shell or the transition layer.

  16. Fabrication and upconversion luminescence properties of YF3:Er3+ hollow nanofibers via monoaxial electrospinning combined with fluorination method.

    PubMed

    Li, Dan; Dong, Xiangting; Yu, Wensheng; Wang, Jinxian; Liu, Guixia

    2014-06-01

    YF3:Er3+ hollow nanofibers were successfully fabricated via fluorination of the relevant Y2O3:Er3+ hollow nanofibers which were obtained by calcining the electrospun PVP/[Y(NO3)3 + Er(NO3)3] composite nanofibers. The morphology and properties of the products were investigated in detail by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and fluorescence spectrometer. YF3:Er3+ hollow nanofibers were pure orthorhombic phase with space group Pnma and were hollow-centered structure with the mean diameter of 172 +/- 23 nm, and YF3:Er3+ hollow nanofibers were composed of nanoparticles with the diameter ranging from 30 nm to 50 nm. Upconversion emission spectrum analysis manifested that YF3:Er3+ hollow nanofibers emitted strong green and weak red upconversion emission centering at 524 nm, 543 nm and 653 nm, respectively. The green emissions and the red emission were respectively originated from 2H11/2/4S3/2 --> 4I15/2 and 4F9/2 --> 4I15/2 energy levels transitions of the Er3+ ions. Moreover, the emitting colors of YF3:Er3+ hollow nanofibers were located in the green region in CIE chromaticity coordinates diagram. The luminescent intensity of YF3:Er3+ hollow nanofibers was increased remarkably with the increasing doping concentration of Er3+ ions. The possible formation mechanism of YF3:Er3+ upconversion luminescence hollow nanofibers was also discussed. This preparation technique could be applied to prepare other rare earth fluoride upconversion luminescence hollow nanofibers.

  17. Direct imaging the upconversion nanocrystal core/shell structure at the subnanometer level: shell thickness dependence in upconverting optical properties.

    PubMed

    Zhang, Fan; Che, Renchao; Li, Xiaomin; Yao, Chi; Yang, Jianping; Shen, Dengke; Hu, Pan; Li, Wei; Zhao, Dongyuan

    2012-06-13

    Lanthanide-doped upconversion nanoparticles have shown considerable promise in solid-state lasers, three-dimensional flat-panel displays, and solar cells and especially biological labeling and imaging. It has been demonstrated extensively that the epitaxial coating of upconversion (UC) core crystals with a lattice-matched shell can passivate the core and enhance the overall upconversion emission intensity of the materials. However, there are few papers that report a precise link between the shell thickness of core/shell nanoparticles and their optical properties. This is mainly because rare earth fluoride upconversion core/shell structures have only been inferred from indirect measurements to date. Herein, a reproducible method to grow a hexagonal NaGdF(4) shell on NaYF(4):Yb,Er nanocrystals with monolayer control thickness is demonstrated for the first time. On the basis of the cryo-transmission electron microscopy, rigorous electron energy loss spectroscopy, and high-angle annular dark-field investigations on the core/shell structure under a low operation temperature (96 K), direct imaging the NaYF(4):Yb,Er@NaGdF(4) nanocrystal core/shell structure at the subnanometer level was realized for the first time. Furthermore, a strong linear link between the NaGdF(4) shell thickness and the optical response of the hexagonal NaYF(4):Yb,Er@NaGdF(4) core/shell nanocrystals has been established. During the epitaxial growth of the NaGdF(4) shell layer by layer, surface defects of the nanocrystals can be gradually passivated by the homogeneous shell deposition process, which results in the obvious enhancement in overall UC emission intensity and lifetime and is more resistant to quenching by water molecules. PMID:22545710

  18. Local Field Modulation Induced Three-Order Upconversion Enhancement: Combining Surface Plasmon Effect and Photonic Crystal Effect.

    PubMed

    Yin, Ze; Li, Hang; Xu, Wen; Cui, Shaobo; Zhou, Donglei; Chen, Xu; Zhu, Yongsheng; Qin, Guanshi; Song, Hongwei

    2016-04-01

    A 2D surface plasmon photonic crystal (SPPC) is achieved by implanting gold nanorods onto the periodic surface apertures of the poly(methyl methacrylate) (PMMA) opal photonic crystals. On the surface of the SPPC, the overall upconversion luminescence intensity of NaYF4 :Yb(3+) , Er(3+) under 980 nm excitation is improved more than 10(3) fold. The device is easily shifted to a transparent flexible substrate, applied to flexible displays. PMID:26833556

  19. Integrated four-channel all-fiber up-conversion single-photon-detector with adjustable efficiency and dark count

    NASA Astrophysics Data System (ADS)

    Zheng, Ming-Yang; Shentu, Guo-Liang; Ma, Fei; Zhou, Fei; Zhang, Hai-Ting; Dai, Yun-Qi; Xie, Xiuping; Zhang, Qiang; Pan, Jian-Wei

    2016-09-01

    Up-conversion single photon detector (UCSPD) has been widely used in many research fields including quantum key distribution, lidar, optical time domain reflectrometry, and deep space communication. For the first time in laboratory, we have developed an integrated four-channel all-fiber UCSPD which can work in both free-running and gate modes. This compact module can satisfy different experimental demands with adjustable detection efficiency and dark count. We have characterized the key parameters of the UCSPD system.

  20. Phase-Dependent Enhancement of the Green-Emitting Upconversion Fluorescence in LaVO4:Yb(3+), Er(3+).

    PubMed

    Zhang, Feng; Li, Guoqiang; Zhang, Weifeng; Yan, Yu Li

    2015-08-01

    The phase-dependent upconversion luminescence properties of LaVO4:Er(3+) were studied to provide new insights into the design of new upconversion materials with high efficiency. Er(3+)-, Yb(3+)/Er(3+)-doped t-LaVO4 microcrystals were successfully synthesized by the disodium ethylenediaminetetraacetic acid (Na2EDTA)-assisted hydrothermal method. X-ray diffraction (XRD), inductively coupled plasma optical emission spectrometer (ICP-OES), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, luminescence spectroscopy, and thermogravimetric analysis (TGA) were used to characterize the samples. The results indicated that t-LaVO4 presents sheaf-like morphology, and the possible formation mechanism for these sheaves was proposed on the basis of time-dependent experiments. Furthermore, the phase-dependence (i.e., monoclinic- and tetragonal-type) upconversion luminescence properties were systematically studied, and the upconversion mechanisms were proposed according to spectral, pump power, and the concentration of Yb(3+) dependence analyses. It is worthwhile pointing out that the Er(3+)-doped t-LaVO4 exhibits a brighter green emission, which is approximately 10 times that of m-LaVO4:Er(3+) using a continuous 980 nm laser diode as the excitation source. This remarkable improvement was rationally analyzed on the basis of the composition, crystal structures, Raman spectra, morphology, and size. The comparative experiments suggest that the local structure of Er(3+) was considered as an important reason for the higher fluorescence intensity of t-LaVO4:Er(3+), which was also confirmed by the results of density functional theory (DFT) calculations. PMID:26203901

  1. Direct imaging the upconversion nanocrystal core/shell structure at the subnanometer level: shell thickness dependence in upconverting optical properties.

    PubMed

    Zhang, Fan; Che, Renchao; Li, Xiaomin; Yao, Chi; Yang, Jianping; Shen, Dengke; Hu, Pan; Li, Wei; Zhao, Dongyuan

    2012-06-13

    Lanthanide-doped upconversion nanoparticles have shown considerable promise in solid-state lasers, three-dimensional flat-panel displays, and solar cells and especially biological labeling and imaging. It has been demonstrated extensively that the epitaxial coating of upconversion (UC) core crystals with a lattice-matched shell can passivate the core and enhance the overall upconversion emission intensity of the materials. However, there are few papers that report a precise link between the shell thickness of core/shell nanoparticles and their optical properties. This is mainly because rare earth fluoride upconversion core/shell structures have only been inferred from indirect measurements to date. Herein, a reproducible method to grow a hexagonal NaGdF(4) shell on NaYF(4):Yb,Er nanocrystals with monolayer control thickness is demonstrated for the first time. On the basis of the cryo-transmission electron microscopy, rigorous electron energy loss spectroscopy, and high-angle annular dark-field investigations on the core/shell structure under a low operation temperature (96 K), direct imaging the NaYF(4):Yb,Er@NaGdF(4) nanocrystal core/shell structure at the subnanometer level was realized for the first time. Furthermore, a strong linear link between the NaGdF(4) shell thickness and the optical response of the hexagonal NaYF(4):Yb,Er@NaGdF(4) core/shell nanocrystals has been established. During the epitaxial growth of the NaGdF(4) shell layer by layer, surface defects of the nanocrystals can be gradually passivated by the homogeneous shell deposition process, which results in the obvious enhancement in overall UC emission intensity and lifetime and is more resistant to quenching by water molecules.

  2. Enhanced upconversion luminescence through core/shell structures and its application for detecting organic dyes in opaque fishes.

    PubMed

    Hu, Pan; Wu, Xiaofeng; Hu, Shigang; Chen, Zenghui; Yan, Huanyuan; Xi, Zaifang; Yu, Yi; Dai, Gangtao; Liu, Yunxin

    2016-02-01

    Here, we report the enhanced upconversion luminescence of NaLuF4:18%Yb(3+),2%Er(3+) through core/shell structures. Among NaYF4, NaGdF4, and NaLuF4 shells, the first one presents the highest efficiency. These upconversion fluorescent nanoprobes with an oleic acid/PEG hybrid ligand can efficiently capture Rhodamine B (RB) and sodium fluorescein (SF) in opaque fishes to present their residues in vivo through luminescence resonant energy transfer (LRET) processes. It can be confirmed based on LRET technology that no RB is absorbed by opaque fishes after incubating in the aqueous solution of 1 μg ml(-1) RB for one day, while SF residue can be obviously detected after incubating in the aqueous solution of 1 μg ml(-1) SF for one day. The merit of this LRET technology with the upconversion nanoparticle (UCNP) donor is ascribed to the deep penetration depth of the infrared pumping laser and high signal to noise ratio.

  3. NIR to blue light upconversion in Tm3+/Yb3+ codoped BaTiO3 tellurite glass

    NASA Astrophysics Data System (ADS)

    Kumari, Astha; Rai, Vineet Kumar

    2015-05-01

    Upconversion is an interesting optical property, generally shown by rare-earth doped materials. This unusual optical behavior shown by these rare-earths doped materials are due to their peculiar atomic configuration and electronic transitions. Here, the Tm3+-Yb3+ codoped BaTiO3 glass with TeO2 as former has been prepared by conventional melt and quench technique and the upconversion property has been investigated with the help of near infrared (NIR) to Visible UC study. The generation of the visible UC bands around ˜ 476 nm, ˜ 653 nm, ˜ 702 nm and one NIR UC band at ˜795 nm are assigned due to the 1G4→ 3H6, 1G4→ 3F4, 3F2→ 3H6 and 3H4→ 3H6 transitions respectively. The generations of these upconversion bands have been discussed in detail with the help of energy level diagram. The colour coordinates corresponding to the prepared material have been shown with the help of CIE chromaticity diagram. These glasses can be very appropriately used in the fabrication of solid state laser and as NIR to blue light upconverter.

  4. Investigation on upconversion luminescence properties of Gd2O3: Ho3+/Yb3+/Tm3+ nanotubes

    NASA Astrophysics Data System (ADS)

    Ye, Fei; Fang, Yu; Liu, Xiao-bo; Xu, Fang; Song, Ying-lin

    2013-09-01

    Lanthanide doped oxides nano materials have novel optical, physical and structural properties. Cubic Ho3+-Yb3+-Tm3+ co-doped Gd2O3 nanotubes are synthetize by a simple wet-chemical route at low temperature and ambient pressure followed by subsequent annealing heat treatment in muffle furnace. Nanotubes are formed by adjusting the pH value of reacting solution. The introduction of Yb3+ leads to strong visible upconversion luminescence and change the intensity ratio of the green, blue and red luminescence. In trichromatic laser display, research of how to enhance blue light is in the bottleneck period. In the experiment, the blue emission has been successfully improved. In certain doping ratio, distinct enhancement of blue emission and obvious degradation of green light have been observed, which is discussed in detail. X-Ray powder diffraction (XRD), scanning electron microscope (SEM) and upconversion (UC) emission spectra are used to characterize the sample. Strong and adjusted upconversion luminescence determine that the nano material is a potential candidate for applications of biological probe, color displays, lighting and photonics.

  5. Novel rare earth ions-doped oxyfluoride nano-composite with efficient upconversion white-light emission

    SciTech Connect

    Chen Daqin; Wang Yuansheng Yu Yunlong; Huang Ping; Weng Fangyi

    2008-10-15

    Transparent SiO{sub 2}-Al{sub 2}O{sub 3}-NaF-YF{sub 3} bulk nano-composites triply doped with Ho{sup 3+}, Tm{sup 3+} and Yb{sup 3+} were fabricated by melt-quenching and subsequent heating. X-ray diffraction and transmission electron microscopy measurements demonstrated the homogeneous precipitation of the {beta}-YF{sub 3} crystals with mean size of 20 nm among the glass matrix, and rare earth ions were found to partition into these nano-crystals. Under single 976 nm laser excitation, intense red, green and blue upconversion emissions were simultaneously observed owing to the successive energy transfer from Yb{sup 3+} to Ho{sup 3+} or Tm{sup 3+}. Various colors of luminescence, including bright perfect white light, can be easily tuned by adjusting the concentrations of the rare earth ions in the material. The overall energy efficiency of the white-light upconversion was estimated to be about 0.2%. - Graphical abstract: Under single 976 nm laser excitation, intense red, green and blue upconversion emissions were simultaneously observed owing to the successive energy transfer from Yb{sup 3+} to Ho{sup 3+} or Tm{sup 3+}. Various colors of luminescence, including bright perfect white light with CIE-X=0.351 and CIE-Y=0.306, can be easily tuned by adjusting the concentrations of the rare earth ions in the transparent oxyfluoride glass ceramics.

  6. Three-dimensional quick response code based on inkjet printing of upconversion fluorescent nanoparticles for drug anti-counterfeiting.

    PubMed

    You, Minli; Lin, Min; Wang, Shurui; Wang, Xuemin; Zhang, Ge; Hong, Yuan; Dong, Yuqing; Jin, Guorui; Xu, Feng

    2016-05-21

    Medicine counterfeiting is a serious issue worldwide, involving potentially devastating health repercussions. Advanced anti-counterfeit technology for drugs has therefore aroused intensive interest. However, existing anti-counterfeit technologies are associated with drawbacks such as the high cost, complex fabrication process, sophisticated operation and incapability in authenticating drug ingredients. In this contribution, we developed a smart phone recognition based upconversion fluorescent three-dimensional (3D) quick response (QR) code for tracking and anti-counterfeiting of drugs. We firstly formulated three colored inks incorporating upconversion nanoparticles with RGB (i.e., red, green and blue) emission colors. Using a modified inkjet printer, we printed a series of colors by precisely regulating the overlap of these three inks. Meanwhile, we developed a multilayer printing and splitting technology, which significantly increases the information storage capacity per unit area. As an example, we directly printed the upconversion fluorescent 3D QR code on the surface of drug capsules. The 3D QR code consisted of three different color layers with each layer encoded by information of different aspects of the drug. A smart phone APP was designed to decode the multicolor 3D QR code, providing the authenticity and related information of drugs. The developed technology possesses merits in terms of low cost, ease of operation, high throughput and high information capacity, thus holds great potential for drug anti-counterfeiting.

  7. A cobalt oxyhydroxide-modified upconversion nanosystem for sensitive fluorescence sensing of ascorbic acid in human plasma.

    PubMed

    Cen, Yao; Tang, Jun; Kong, Xiang-Juan; Wu, Shuang; Yuan, Jing; Yu, Ru-Qin; Chu, Xia

    2015-09-01

    Ascorbic acid (AA), a potent antioxidant readily scavenging reactive species, is a crucial micronutrient involved in many biochemical processes. Here, we have developed a cobalt oxyhydroxide (CoOOH)-modified upconversion nanosystem for fluorescence sensing of AA activity in human plasma. The nanosystem consists of upconversion nanoparticles (UCNPs) NaYF4:30% Yb,0.5% Tm@NaYF4, which serve as energy donors, and CoOOH nanoflakes formed on the surface of UCNPs, which act as efficient energy acceptors. The fluorescence resonance energy transfer (FRET) process from the UCNPs to the absorbance of the CoOOH nanoflakes occurs in the nanosystem. The AA-mediated specific redox reaction reduces CoOOH into Co(2+), leading to the inhibition of FRET, and resulting in the recovery of upconversion emission spectra. On the basis of these features, the nanosystem can be used for sensing AA activity with sensitivity and selectivity. Moreover, due to the minimizing background interference provided by UCNPs, the nanosystem has been applied to monitoring AA levels in human plasma sample with satisfactory results. The proposed approach may potentially provide an analytical platform for research and clinical diagnosis of AA related diseases. PMID:26222243

  8. The effect of SiO2 on TiO2 up-conversion photoluminescence film

    NASA Astrophysics Data System (ADS)

    Meng, Xiaoqi; Li, Lianqiang; Zou, Kaishun; Liu, Juncheng

    2014-11-01

    In order to increase the photoelectric conversion efficiency of silicon solar cell, the up-conversion film has been tried to enhance the response of the solar cells to the infrared band. Yb3+, Er3+ co-doped SiO2/TiO2 composite films with different Ti/Si molar ratio were deposited on the glass substrate with sol-gel method and spin-coating technique. The effect of different molar ratio of Ti/Si on the film's morphology and optical properties was investigated. The morphology, the absorption spectra and photoluminescence (PL) spectra of the film were tested and analyzed. After the film was annealed at 900 °C, the XRD diffraction pattern indicated that rare earths ions have evenly dispersed into the matrix lattice. The FT-IR showed that Si ions entered into the lattice of titanium dioxide, and the Ti-O-Si bonds came into being. When the film pumped with a laser of 980 nm, there were a dominant red emission and several weak green peaks. In addition, with the increase of the mole ratio of Si/Ti, the intensity of the film's up-conversion luminescence increases at first and then decreases. When the molar ratio of Si/Ti is 1/8, the sample had the highest intensity of up-conversion luminescence.

  9. Three-dimensional quick response code based on inkjet printing of upconversion fluorescent nanoparticles for drug anti-counterfeiting.

    PubMed

    You, Minli; Lin, Min; Wang, Shurui; Wang, Xuemin; Zhang, Ge; Hong, Yuan; Dong, Yuqing; Jin, Guorui; Xu, Feng

    2016-05-21

    Medicine counterfeiting is a serious issue worldwide, involving potentially devastating health repercussions. Advanced anti-counterfeit technology for drugs has therefore aroused intensive interest. However, existing anti-counterfeit technologies are associated with drawbacks such as the high cost, complex fabrication process, sophisticated operation and incapability in authenticating drug ingredients. In this contribution, we developed a smart phone recognition based upconversion fluorescent three-dimensional (3D) quick response (QR) code for tracking and anti-counterfeiting of drugs. We firstly formulated three colored inks incorporating upconversion nanoparticles with RGB (i.e., red, green and blue) emission colors. Using a modified inkjet printer, we printed a series of colors by precisely regulating the overlap of these three inks. Meanwhile, we developed a multilayer printing and splitting technology, which significantly increases the information storage capacity per unit area. As an example, we directly printed the upconversion fluorescent 3D QR code on the surface of drug capsules. The 3D QR code consisted of three different color layers with each layer encoded by information of different aspects of the drug. A smart phone APP was designed to decode the multicolor 3D QR code, providing the authenticity and related information of drugs. The developed technology possesses merits in terms of low cost, ease of operation, high throughput and high information capacity, thus holds great potential for drug anti-counterfeiting. PMID:27119377

  10. Short-wavelength upconversion emissions in Ho3+/Yb3+ codoped glass ceramic and the optical thermometry behavior.

    PubMed

    Xu, Wei; Gao, Xiaoyang; Zheng, Longjiang; Zhang, Zhiguo; Cao, Wenwu

    2012-07-30

    Ho(3+)/Yb(3+) codoped glass ceramic was prepared by melt-quenching and subsequent thermal treatment. Under a 980 nm diode laser excitation, upconversion emissions from Ho(3+) ions centered at 540, 650, and 750 nm were greatly enhanced compared with those in the precursor glass. Especially, the short-wavelength upconversion emissions centered at 360, 385, 418, 445, and 485 nm were successfully obtained in the glass ceramic. An explanation for this phenomenon is given based on the fluorescence decay curve measurements. In addition, an optical temperature sensor based on the blue upconversion emissions from (5)F(2,3)/(3)K(8)→(5)I(8) and (5)F(1)/(5)G(6)→(5)I(8) transitions in Ho(3+)/Yb(3+) codoped glass ceramic has been developed. It was found that by using fluorescence intensity ratio technique, appreciable sensitivity for temperature measurement can be achieved by using the Ho(3+)/Yb(3+) codoped glass ceramic. This result makes the Ho(3+)/Yb(3+) codoped glass ceramic be a promising candidate for sensitive optical temperature sensor with high resolution and good accuracy.

  11. Uniform NaYF{sub 4}:Yb, Tm hexagonal submicroplates: Controlled synthesis and enhanced UV and blue upconversion luminescence

    SciTech Connect

    Huang, Wenjuan; Ding, Mingye; Huang, Hengming; Jiang, Chenfei; Song, Yan; Ni, Yaru; Lu, Chunhua; Xu, Zhongzi

    2013-02-15

    Graphical abstract: Display Omitted Highlights: ► β-NaYF{sub 4} phosphors as an excellent upconversion materials. ► Oleic acid can promote the transformation of α → β phase NaYF{sub 4}. ► The shape and size of β-NaYF{sub 4} submicroplate can be tuned by reactant concentration. ► Enhanced UV and blue peaks can be obtained by varying Yb{sup 3+} and Tm{sup 3+} concentration. -- Abstract: We reported the preparation of cubic (α-) and hexagonal (β-) NaYF{sub 4} particles in high boiling organic solvents 1-octadecene (ODE) and oleic acid (OA), through a thermal decomposition synthesis route. The as-prepared products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), photoluminescence (PL) spectra. By tuning the OA/ODE volume ratio and reactant concentration, we could manipulate the morphology, size, and crystal structure of the products. Highly uniform β-NaYF{sub 4} submicroplates were obtained from α-NaYF{sub 4} nanoparticles by increasing the OA/ODE volume ratio, while the phase kept unchanged with the increasing of reactant concentration. Upconversion emissions from UV to NIR emissions were observed in β-NaYF{sub 4} hexagonal submicroplates under 980 nm laser diode excitation. In addition, the enhanced UV and blue upconversion emissions were obtained by varying Tm{sup 3+} and Yb{sup 3+} ion concentration.

  12. Expression of CD1d protein in human testis showing normal and abnormal spermatogenesis.

    PubMed

    Adly, Mohamed A; Abdelwahed Hussein, Mahmoud-Rezk

    2011-05-01

    CD1d is a member of CD1 family of transmembrane glycoproteins, which represent antigen-presenting molecules. Immunofluorescent staining methods were utilized to examine expression pattern of CD1d in human testicular specimens. In testis showing normal spermatogenesis, a strong CD1d cytoplasmic expression was seen the Sertoli cells, spermatogonia, and Leydig cells. A moderate expression was observed in the spermatocytes. In testes showing maturation arrest, CD1d expression was strong in the Sertoli cells and weak in spermatogonia and spermatocytes compared to testis with normal spermatogenesis. In Sertoli cell only syndrome, CD1d expression was strong in the Sertoli and Leydig cells. This preliminary study displayed testicular infertility-related changes in CD1d expression. The ultrastructural changes associated with with normal and abnormal spermatogenesis are open for further investigations.

  13. Examination of 1D Solar Cell Model Limitations Using 3D SPICE Modeling: Preprint

    SciTech Connect

    McMahon, W. E.; Olson, J. M.; Geisz, J. F.; Friedman, D. J.

    2012-06-01

    To examine the limitations of one-dimensional (1D) solar cell modeling, 3D SPICE-based modeling is used to examine in detail the validity of the 1D assumptions as a function of sheet resistance for a model cell. The internal voltages and current densities produced by this modeling give additional insight into the differences between the 1D and 3D models.

  14. Tunable Design of Structural Colors Produced by Pseudo-1D Photonic Crystals of Graphene Oxide.

    PubMed

    Tong, Liping; Qi, Wei; Wang, Mengfan; Huang, Renliang; Su, Rongxin; He, Zhimin

    2016-07-01

    It is broadly observed that graphene oxide (GO) films appear transparent with a thickness of about several nanometers, whereas they appear dark brown or almost black with thickness of more than 1 μm. The basic color mechanism of GO film on a sub-micrometer scale, however, is not well understood. This study reports on GO pseudo-1D photonic crystals (p1D-PhCs) exhibiting tunable structural colors in the visible wavelength range owing to its 1D Bragg nanostructures. Striking structural colors of GO p1D-PhCs could be tuned by simply changing either the volume or concentration of the aqueous GO dispersion during vacuum filtration. Moreover, the quantitative relationship between thickness and reflection wavelength of GO p1D-PhCs has been revealed, thereby providing a theoretical basis to rationally design structural colors of GO p1D-PhCs. The spectral response of GO p1D-PhCs to humidity is also obtained clearly showing the wavelength shift of GO p1D-PhCs at differently relative humidity values and thus encouraging the integration of structural color printing and the humidity-responsive property of GO p1D-PhCs to develop a visible and fast-responsive anti-counterfeiting label. The results pave the way for a variety of potential applications of GO in optics, structural color printing, sensing, and anti-counterfeiting.

  15. Exercise increases TBC1D1 phosphorylation in human skeletal muscle

    PubMed Central

    Jessen, Niels; An, Ding; Lihn, Aina S.; Nygren, Jonas; Hirshman, Michael F.; Thorell, Anders

    2011-01-01

    Exercise and weight loss are cornerstones in the treatment and prevention of type 2 diabetes, and both interventions function to increase insulin sensitivity and glucose uptake into skeletal muscle. Studies in rodents demonstrate that the underlying mechanism for glucose uptake in muscle involves site-specific phosphorylation of the Rab-GTPase-activating proteins AS160 (TBC1D4) and TBC1D1. Multiple kinases, including Akt and AMPK, phosphorylate TBC1D1 and AS160 on distinct residues, regulating their activity and allowing for GLUT4 translocation. In contrast to extensive rodent-based studies, the regulation of AS160 and TBC1D1 in human skeletal muscle is not well understood. In this study, we determined the effects of dietary intervention and a single bout of exercise on TBC1D1 and AS160 site-specific phosphorylation in human skeletal muscle. Ten obese (BMI 33.4 ± 2.4, M-value 4.3 ± 0.5) subjects were studied at baseline and after a 2-wk dietary intervention. Muscle biopsies were obtained from the subjects in the resting (basal) state and immediately following a 30-min exercise bout (70% V̇o2 max). Muscle lysates were analyzed for AMPK activity and Akt phosphorylation and for TBC1D1 and AS160 phosphorylation on known or putative AMPK and Akt sites as follows: AS160 Ser711 (AMPK), TBC1D1 Ser231 (AMPK), TBC1D1 Ser660 (AMPK), TBC1D1 Ser700 (AMPK), and TBC1D1 Thr590 (Akt). The diet intervention that consisted of a major shift in the macronutrient composition resulted in a 4.2 ± 0.4 kg weight loss (P < 0.001) and a significant increase in insulin sensitivity (M value 5.6 ± 0.6), but surprisingly, there was no effect on expression or phosphorylation of any of the muscle-signaling proteins. Exercise increased muscle AMPKα2 activity but did not increase Akt phosphorylation. Exercise increased phosphorylation on AS160 Ser711, TBC1D1 Ser231, and TBC1D1 Ser660 but had no effect on TBC1D1 Ser700. Exercise did not increase TBC1D1 Thr590 phosphorylation or TBC1D1/AS160 PAS

  16. Understanding the infrared to visible upconversion luminescence properties of Er{sup 3+}/Yb{sup 3+} co-doped BaMoO{sub 4} nanocrystals

    SciTech Connect

    Adhikari, Rajesh; Choi, Jinhyuk; Narro-García, R.; De la Rosa, E.; Sekino, Tohru; Lee, Soo Wohn

    2014-08-15

    In this paper we report the infrared to visible upconversion luminescence properties of Er{sup 3+}/Yb{sup 3+} co-doped BaMoO{sub 4} nanocrystals synthesized via microwave assisted sol–gel processing route. Structural, morphological and upconversion luminescence properties were investigated by X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), UV–vis diffuse reflectance spectroscopy (UV–vis DRS) and Upconversion Photoluminescence spectra analysis. Results revealed that the oval shaped BaMoO{sub 4} nanocrystals ranging in size from 40 to 60 nm having tetragonal scheelite crystal structure were obtained by sol–gel route. The infrared to visible upconversion luminescence has been investigated in Er{sup 3+}/Yb{sup 3+} co-doped in BaMoO{sub 4}with different Yb{sup 3+} concentrations. Intense green upconversion emissions around 528, 550 nm, and red emission at 657 nm corresponding to the {sup 2}H{sub 11/2}, {sup 4}S{sub 3/2}, and {sup 4}F{sub 9/2} transitions, respectively to the {sup 4}I{sub 15/2} ground state were observed when excited by CW laser radiation at 980 nm. The green emissions were greatly enhanced after the addition of sensitizer (Yb{sup 3+} ions). The effect of Yb{sup 3+} on the upconversion luminescence intensity was analyzed and explained in terms of the energy transfer process based. The reported work establishes the understanding of molybdates as an alternative host material for upconversion luminescence. - Graphical abstract: Infrared to visible upconversion luminescence of Er{sup 3+}/Yb{sup 3+} co-doped BaMoO{sub 4} nanocrystals. - Highlights: • Nanocrystals were synthesized by microwave assisted sol–gel processing route. • Strong green emissions were observed in Er{sup 3+}/Yb{sup 3+} co-doped BaMoO{sub 4} nanocrystals. • Provides an insight on Upconversion luminescence properties of oxides host materials.

  17. Folic acid-functionalized up-conversion nanoparticles: toxicity studies in vivo and in vitro and targeted imaging applications

    NASA Astrophysics Data System (ADS)

    Sun, Lining; Wei, Zuwu; Chen, Haige; Liu, Jinliang; Guo, Jianjian; Cao, Ming; Wen, Tieqiao; Shi, Liyi

    2014-07-01

    Folate receptors (FRs) are overexpressed on a variety of human cancer cells and tissues, including cancers of the breast, ovaries, endometrium, and brain. This over-expression of FRs can be used to target folate-linked imaging specifically to FR-expressing tumors. Fluorescence is emerging as a powerful new modality for molecular imaging in both the diagnosis and treatment of disease. Combining innovative molecular biology and chemistry, we prepared three kinds of folate-targeted up-conversion nanoparticles as imaging agents (UCNC-FA: UCNC-Er-FA, UCNC-Tm-FA, and UCNC-Er,Tm-FA). In vivo and in vitro toxicity studies showed that these nanoparticles have both good biocompatibility and low toxicity. Moreover, the up-conversion luminescence imaging indicated that they have good targeting to HeLa cells and can therefore serve as potential fluorescent contrast agents.Folate receptors (FRs) are overexpressed on a variety of human cancer cells and tissues, including cancers of the breast, ovaries, endometrium, and brain. This over-expression of FRs can be used to target folate-linked imaging specifically to FR-expressing tumors. Fluorescence is emerging as a powerful new modality for molecular imaging in both the diagnosis and treatment of disease. Combining innovative molecular biology and chemistry, we prepared three kinds of folate-targeted up-conversion nanoparticles as imaging agents (UCNC-FA: UCNC-Er-FA, UCNC-Tm-FA, and UCNC-Er,Tm-FA). In vivo and in vitro toxicity studies showed that these nanoparticles have both good biocompatibility and low toxicity. Moreover, the up-conversion luminescence imaging indicated that they have good targeting to HeLa cells and can therefore serve as potential fluorescent contrast agents. Electronic supplementary information (ESI) available: Up-conversion luminescence spectra of UCNC-Er and UCNC-Er-FA, UCNC-Tm and UCNC-Tm-FA. Confocal luminescence imaging data collected as a series along the Z optical axis. See DOI: 10.1039/c4nr02312a

  18. Potent neutralizing anti-CD1d antibody reduces lung cytokine release in primate asthma model.

    PubMed

    Nambiar, Jonathan; Clarke, Adam W; Shim, Doris; Mabon, David; Tian, Chen; Windloch, Karolina; Buhmann, Chris; Corazon, Beau; Lindgren, Matilda; Pollard, Matthew; Domagala, Teresa; Poulton, Lynn; Doyle, Anthony G

    2015-01-01

    CD1d is a receptor on antigen-presenting cells involved in triggering cell populations, particularly natural killer T (NKT) cells, to release high levels of cytokines. NKT cells are implicated in asthma pathology and blockade of the CD1d/NKT cell pathway may have therapeutic potential. We developed a potent anti-human CD1d antibody (NIB.2) that possesses high affinity for human and cynomolgus macaque CD1d (KD ∼100 pM) and strong neutralizing activity in human primary cell-based assays (IC50 typically <100 pM). By epitope mapping experiments, we showed that NIB.2 binds to CD1d in close proximity to the interface of CD1d and the Type 1 NKT cell receptor β-chain. Together with data showing that NIB.2 inhibited stimulation via CD1d loaded with different glycolipids, this supports a mechanism whereby NIB.2 inhibits NKT cell activation by inhibiting Type 1 NKT cell receptor β-chain interactions with CD1d, independent of the lipid antigen in the CD1d antigen-binding cleft. The strong in vitro potency of NIB.2 was reflected in vivo in an Ascaris suum cynomolgus macaque asthma model. Compared with vehicle control, NIB.2 treatment significantly reduced bronchoalveolar lavage (BAL) levels of Ascaris-induced cytokines IL-5, IL-8 and IL-1 receptor antagonist, and significantly reduced baseline levels of GM-CSF, IL-6, IL-15, IL-12/23p40, MIP-1α, MIP-1β, and VEGF. At a cellular population level NIB.2 also reduced numbers of BAL lymphocytes and macrophages, and blood eosinophils and basophils. We demonstrate that anti-CD1d antibody blockade of the CD1d/NKT pathway modulates inflammatory parameters in vivo in a primate inflammation model, with therapeutic potential for diseases where the local cytokine milieu is critical.

  19. Potent neutralizing anti-CD1d antibody reduces lung cytokine release in primate asthma model

    PubMed Central

    Nambiar, Jonathan; Clarke, Adam W; Shim, Doris; Mabon, David; Tian, Chen; Windloch, Karolina; Buhmann, Chris; Corazon, Beau; Lindgren, Matilda; Pollard, Matthew; Domagala, Teresa; Poulton, Lynn; Doyle, Anthony G

    2015-01-01

    CD1d is a receptor on antigen-presenting cells involved in triggering cell populations, particularly natural killer T (NKT) cells, to release high levels of cytokines. NKT cells are implicated in asthma pathology and blockade of the CD1d/NKT cell pathway may have therapeutic potential. We developed a potent anti-human CD1d antibody (NIB.2) that possesses high affinity for human and cynomolgus macaque CD1d (KD ∼100 pM) and strong neutralizing activity in human primary cell-based assays (IC50 typically <100 pM). By epitope mapping experiments, we showed that NIB.2 binds to CD1d in close proximity to the interface of CD1d and the Type 1 NKT cell receptor β-chain. Together with data showing that NIB.2 inhibited stimulation via CD1d loaded with different glycolipids, this supports a mechanism whereby NIB.2 inhibits NKT cell activation by inhibiting Type 1 NKT cell receptor β-chain interactions with CD1d, independent of the lipid antigen in the CD1d antigen-binding cleft. The strong in vitro potency of NIB.2 was reflected in vivo in an Ascaris suum cynomolgus macaque asthma model. Compared with vehicle control, NIB.2 treatment significantly reduced bronchoalveolar lavage (BAL) levels of Ascaris-induced cytokines IL-5, IL-8 and IL-1 receptor antagonist, and significantly reduced baseline levels of GM-CSF, IL-6, IL-15, IL-12/23p40, MIP-1α, MIP-1β, and VEGF. At a cellular population level NIB.2 also reduced numbers of BAL lymphocytes and macrophages, and blood eosinophils and basophils. We demonstrate that anti-CD1d antibody blockade of the CD1d/NKT pathway modulates inflammatory parameters in vivo in a primate inflammation model, with therapeutic potential for diseases where the local cytokine milieu is critical. PMID:25751125

  20. Electronic-to-vibrational energy transfer efficiency in the O/1 D/-N2 and O/1 D/-CO systems

    NASA Technical Reports Server (NTRS)

    Slanger, T. G.; Black, G.

    1974-01-01

    With the aid of a molecular resonance fluorescence technique, which utilizes optical pumping from the v = 1 level of the ground state of CO by A 1 Pi-X 1 Sigma radiation, a study is made of the efficiency of E-V transfer from O(1 D) to CO. O(1 D) is generated at a known rate by O2 photodissociation at 1470 A in an intermittent mode, and the small modulation of the fluorescent signal associated with CO (v = 1) above the normal thermal background is interpreted in terms of E-V transfer efficiency. The CO (v = 1) lifetime in this system is determined mainly by resonance trapping of the IR fundamental band, and is found to be up to ten times longer than the natural radiative lifetime. For CO, (40 plus or minus 8)% of the O(1 D) energy is converted into vibrational energy. By observing the effect of N2 on the CO (v = 1) fluorescent intensity and lifetime, it is possible to obtain the E-V transfer efficiency for the system O(1 D)-N2 relative to that for O(1 D)-CO. The results indicate that the efficiency for N2 is (83 plus or minus 10)% of that for CO.

  1. Mapping of the serotonin 5-HT{sub 1D{alpha}} autoreceptor gene (HTR1D) on chromosome 1 using a silent polymorphism in the coding region

    SciTech Connect

    Ozaki, N.; Lappalainen, J.; Linnoila, M.

    1995-04-24

    Serotonin (5-HT){sub ID} receptors are 5-HT release-regulating autoreceptors in the human brain. Abnormalities in brain 5-HT function have been hypothesized in the pathophysiology of various psychiatric disorders, including obsessive-compulsive disorder, autism, mood disorders, eating disorders, impulsive violent behavior, and alcoholism. Thus, mutations occurring in 5-HT autoreceptors may cause or increase the vulnerability to any of these conditions. 5-HT{sub 1D{alpha}} and 5-HT{sub 1D{Beta}} subtypes have been previously localized to chromosomes 1p36.3-p34.3 and 6q13, respectively, using rodent-human hybrids and in situ localization. In this communication, we report the detection of a 5-HT{sub 1D{alpha}} receptor gene polymorphism by single strand conformation polymorphism (SSCP) analysis of the coding sequence. The polymorphism was used for fine scale linkage mapping of 5-HT{sub 1D{alpha}} on chromosome 1. This polymorphism should also be useful for linkage studies in populations and in families. Our analysis also demonstrates that functionally significant coding sequence variants of the 5-HT{sub 1D{alpha}} are probably not abundant either among alcoholics or in the general population. 14 refs., 1 fig., 1 tab.

  2. Neodymium 1D systems: targeting new sources for field-induced slow magnetization relaxation.

    PubMed

    Jassal, Amanpreet Kaur; Aliaga-Alcalde, Núria; Corbella, Montserrat; Aravena, Daniel; Ruiz, Eliseo; Hundal, Geeta

    2015-09-28

    Two non-isostructural homometallic 1D neodymium species displaying field-induced slow magnetization relaxations are presented together with theoretical studies. It is established that both systems are better described as organized 1D single molecule magnets (SMMs). Studies show great potential of Nd(III) ions to provide homometallic chains with slow magnetic relaxation.

  3. Characterization of the fraction components using 1D TOCSY and 1D ROESY experiments. Four new spirostane saponins from Agave brittoniana Trel. spp. Brachypus.

    PubMed

    Macías, Francisco A; Guerra, José O; Simonet, Ana M; Nogueiras, Clara M

    2007-07-01

    A careful NMR analysis, especially 1D TOCSY and 1D ROESY, of two refined saponin fractions allowed us to determine the structures of four new saponins from a polar extract of the Agave brittoniana Trel. spp. Brachypus leaves. A full assignment of the 1H and 13C spectral data for these new saponins, agabrittonosides A-D (1-4), and one previously known saponin, karatavioside A (5) is reported. Their structures were established using a combination of 1D and 2D (1H, 1H-COSY, TOCSY, ROESY, g-HSQC, g-HMBC and g-HSQC-TOCSY) NMR techniques and ESI-MS. Moreover, the work represents a new approach to structural elucidation of saponins in refined fractions by NMR investigations.

  4. Decays B(s)→a1(b1)D(s), a1(b1)D(s)* in the perturbative QCD approach

    NASA Astrophysics Data System (ADS)

    Zhang, Zhi-Qing

    2013-04-01

    Within the framework of the perturbative QCD approach, we study the branching ratios of the two-body charmed decays B(s)→a1(b1)D(s), a1(b1)D(s)*, which, including Cabibbo-Kobayashi-Maskawa, allowed and suppressed decays. Our calculations are consistent with the currently available data and the experimental upper limits. Certainly, many of these predicted channels have not been measured by experiments and can be confronted with the future experimental data. We also discuss the polarization factions of the decays B(s)→a1(b1)D(s)*, some of which are sensitive to the distinct Gegenbauer moments of the wave functions and the decay constants of mesons a1 and b1.

  5. Amphiphilic copolymer coated upconversion nanoparticles for near-infrared light-triggered dual anticancer treatment

    NASA Astrophysics Data System (ADS)

    Yang, Shun; Li, Najun; Liu, Zhuang; Sha, Wenwei; Chen, Dongyun; Xu, Qingfeng; Lu, Jianmei

    2014-11-01

    The light-triggered controlled release of anticancer drugs accompanied with NIR-responsive photodynamic therapy was prepared via a self-assembly process. Firstly, Mn2+-doped upconversion nanoparticles (UCNPs) were coated with a mesoporous silica shell and modified with photosensitizer (Chlorin e6) and long alkyl chains. And then the NIR light-responsive amphiphilic copolymer containing 9,10-dialkoxyanthracene groups was synthesized and then coated as the outermost layer. Upon irradiation with a 980 nm laser, the CCUCNPs@PM would absorb and then convert the NIR light to higher-energy visible red light (660 nm) via the UCNPs-based core, which could excite Chlorin e6 (Ce-6) to produce singlet oxygen (1O2). Then the 1O2-sensitive dialkoxyanthracene group in the amphiphilic copolymer would be degraded and detach from the surface of the CCUCNPs@PM, followed by the controlled release of the pre-loaded drugs and the photodynamic therapy for cancer cells caused by the excess 1O2. In vitro and in vivo experiments also demonstrated that the drug-loaded CCUCNPs@PM possessed better therapeutic efficacy compared with vacant ones. Therefore, the NIR light-controlled chemotherapy and photodynamic therapy could be realized simultaneously by CCUCNPs@PM.The light-triggered controlled release of anticancer drugs accompanied with NIR-responsive photodynamic therapy was prepared via a self-assembly process. Firstly, Mn2+-doped upconversion nanoparticles (UCNPs) were coated with a mesoporous silica shell and modified with photosensitizer (Chlorin e6) and long alkyl chains. And then the NIR light-responsive amphiphilic copolymer containing 9,10-dialkoxyanthracene groups was synthesized and then coated as the outermost layer. Upon irradiation with a 980 nm laser, the CCUCNPs@PM would absorb and then convert the NIR light to higher-energy visible red light (660 nm) via the UCNPs-based core, which could excite Chlorin e6 (Ce-6) to produce singlet oxygen (1O2). Then the 1O2-sensitive

  6. Upconversion luminescence enhancement in plasmonic architecture with random assembly of metal nanodomes

    NASA Astrophysics Data System (ADS)

    Lee, Gi Yong; Jung, Kinam; Jang, Ho Seong; Kyhm, Jihoon; Han, Il Ki; Park, Byoungnam; Ju, Honglyoul; Kwon, S. Joon; Ko, Hyungduk

    2016-01-01

    We report an experimental study on the highly enhanced upconversion luminescence (UCL) of β-NaYF4:Yb3+/Er3+ nanocrystals (NCs) in a plasmonic architecture. For the architecture, we designed a thin film device composed of a thin layer of NCs capped with an upper layer of a plasmonic nanodome array (pNDA) and lower substrate of a back reflector (BR). Compared to the UCL intensity observed in a glass reference substrate, the designed plasmonic architecture exhibits distinctively strong luminescence enhanced by up to 800-fold. The intensity considerably exceeds the previously reported luminescence intensity regardless of the excitation power. We elucidated a mechanism explaining the large UCL enhancement, which quantitatively analyzes the combination of plasmonic effects as well as multiple large scattering. More importantly, we provided a detailed analysis of the Ag NDA-derived and BR-assisted plasmonic effects that contribute to an increase in the radiative decay rate and an enhancement of the absorption of incident light. The present study is expected to be beneficial for designing a thin film-based plasmonic structure with a randomized metal nanostructure for high-efficiency photovoltaic devices and infrared detectors.We report an experimental study on the highly enhanced upconversion luminescence (UCL) of β-NaYF4:Yb3+/Er3+ nanocrystals (NCs) in a plasmonic architecture. For the architecture, we designed a thin film device composed of a thin layer of NCs capped with an upper layer of a plasmonic nanodome array (pNDA) and lower substrate of a back reflector (BR). Compared to the UCL intensity observed in a glass reference substrate, the designed plasmonic architecture exhibits distinctively strong luminescence enhanced by up to 800-fold. The intensity considerably exceeds the previously reported luminescence intensity regardless of the excitation power. We elucidated a mechanism explaining the large UCL enhancement, which quantitatively analyzes the combination of

  7. TBC1D1 reduces palmitate oxidation by inhibiting β-HAD activity in skeletal muscle.

    PubMed

    Maher, A C; McFarlan, J; Lally, J; Snook, L A; Bonen, A

    2014-11-01

    In skeletal muscle the Rab-GTPase-activating protein TBC1D1 has been implicated in the regulation of fatty acid oxidation by an unknown mechanism. We determined whether TBC1D1 altered fatty acid utilization via changes in protein-mediated fatty acid transport and/or selected enzymes regulating mitochondrial fatty acid oxidation. We also determined the effects of TBC1D1 on glucose transport and oxidation. Electrotransfection of mouse soleus muscles with TBC1D1 cDNA increased TBC1D1 protein after 2 wk (P<0.05), without altering its paralog AS160. TBC1D1 overexpression decreased basal palmitate oxidation (-22%) while blunting 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR)-stimulated palmitate oxidation (-18%). There was a tendency to increase fatty acid esterification (+10 nmol·g(-1)·60 min(-1), P=0.07), which reflected the reduction in fatty acid oxidation (-12 nmol·g(-1)·60 min(-1)). Concomitantly, basal (+21%) and AICAR-stimulated glucose oxidation (+8%) were increased in TBC1D1-transfected muscles relative to their respective controls (P<0.05), independent of changes in GLUT4 and glucose transport. The reductions in TBC1D1-mediated fatty acid oxidation could not be attributed to changes in the transporter FAT/CD36, muscle mitochondrial content, CPT1 expression or the expression and phosphorylation of AS160, acetyl-CoA carboxylase, or AMPK. However, TBC1D1 overexpression reduced β-HAD enzyme activity (-18%, P<0.05). In conclusion, TBC1D1-mediated reduction of muscle fatty acid oxidation appears to occur via inhibition of β-HAD activity.

  8. An optical sensing composite for cysteine detection using up-conversion nanoparticles and a rhodamine-derived chemosensor: Construction, characterization, photophysical feature and sensing performance.

    PubMed

    Kai, Song; Cheng-Wen, Lu; Yi-Nan, Ding; Tian, Luan; Guang-Ye, Wang; Jing-Mei, Lu; Li-Quan, Guo

    2016-02-15

    In this paper, we reported an optical sensing composite for cysteine detection. A chemosensor derived from rhodamine 6G was synthesized and characterized. To minimize its photobleaching, up-conversion nanocrystals β-NaYF4:Yb(3+)/Er(3+) were prepared and modified with α-cyclodextrin, serving as excitation host. Under 980nm laser excitation, emission of these up-conversion nanocrystals overlapped well with the absorption of our chemosensor. Energy transfer between them was analyzed and confirmed by emission decay analysis. Job's analysis suggested that the complexation equilibrium between our chemosensor and cysteine was a simple one with binding stoichiometry of 1:1. A sensing system was constructed with up-conversion nanocrystals (modified with α-cyclodextrin) and this chemosensor. Emission "turn-on" effect was observed only for cysteine but immune to other competing amino acids and thiols, showing a good selectivity.

  9. An optical sensing composite for cysteine detection using up-conversion nanoparticles and a rhodamine-derived chemosensor: Construction, characterization, photophysical feature and sensing performance

    NASA Astrophysics Data System (ADS)

    Kai, Song; Cheng-Wen, Lu; Yi-Nan, Ding; Tian, Luan; Guang-Ye, Wang; Jing-Mei, Lu; Li-Quan, Guo

    2016-02-01

    In this paper, we reported an optical sensing composite for cysteine detection. A chemosensor derived from rhodamine 6G was synthesized and characterized. To minimize its photobleaching, up-conversion nanocrystals β-NaYF4:Yb3 +/Er3 + were prepared and modified with α-cyclodextrin, serving as excitation host. Under 980 nm laser excitation, emission of these up-conversion nanocrystals overlapped well with the absorption of our chemosensor. Energy transfer between them was analyzed and confirmed by emission decay analysis. Job's analysis suggested that the complexation equilibrium between our chemosensor and cysteine was a simple one with binding stoichiometry of 1:1. A sensing system was constructed with up-conversion nanocrystals (modified with α-cyclodextrin) and this chemosensor. Emission "turn-on" effect was observed only for cysteine but immune to other competing amino acids and thiols, showing a good selectivity.

  10. Enhanced upconversion emission in crystallization-controllable glass-ceramic fiber containing Yb(3+)-Er(3+) codoped CaF2 nanocrystals.

    PubMed

    Peng, Wencai; Fang, Zaijin; Ma, Zhijun; Qiu, Jianrong

    2016-10-01

    Functional nanocrystal-containing materials have been a hot topic in recent years. However, few researches have focused on functional nanocrystals contained in optical glass fibers. In this research, transparent CaF2 glass-ceramic was prepared by a melt-quenching method. Greatly enhanced upconversion luminescence was observed after heat treatment. By applying a novel method called melt-in-tube, precursor fiber free of crystals was fabricated at the drawing temperature where the clad was softened while the core was melted. Glass-ceramic fiber with fiber core containing Yb(3+)-Er(3+) codoped CaF2 nanocrystals was obtained after heat treatment at a relatively low temperature. Electron probe micro-analyzer measurement shows no obvious element diffusion between the core and clad. Greatly enhanced upconversion emission was detected in the glass-ceramic fiber excited by a 980 nm laser, suggesting the developed glass-ceramic fiber is a promising material for upconversion laser. PMID:27576586

  11. Intense upconversion luminescence and effect of local environment for Tm 3+/Yb 3+ co-doped novel TeO 2-BiCl 3 glass system

    NASA Astrophysics Data System (ADS)

    Wang, Guonian; Dai, Shixun; Zhang, Junjie; Wen, Lei; Yang, Jianhu; Jiang, Zhonghong

    2006-05-01

    We present the results of a study that uses theoretical and experimental methods to investigate the characteristics of the upconversion luminescence of Tm 3+/Yb 3+ codoped TeO 2-BiCl 3 glass system as a function of the BiCl 3 fraction. These glasses are potentially important in the design of upconversion fiber lasers. Effect of local environment around Tm 3+ on upconversion fluorescence intensity was analyzed by theoretical calculations. The structure and spectroscopic properties were investigated in the experiments by measuring the Raman spectra, IR transmission spectra, and absorption and fluorescence intensities at room temperature. The results indicate that blue luminescence quantum efficiency increases with increasing BiCl 3 content from 10 to 60 mol%, which were interpreted by the increase of asymmetry of glass structure, decrease of phonon energy and removing of OH - groups.

  12. Enhanced upconversion emission in crystallization-controllable glass-ceramic fiber containing Yb3+-Er3+ codoped CaF2 nanocrystals

    NASA Astrophysics Data System (ADS)

    Peng, Wencai; Fang, Zaijin; Ma, Zhijun; Qiu, Jianrong

    2016-10-01

    Functional nanocrystal-containing materials have been a hot topic in recent years. However, few researches have focused on functional nanocrystals contained in optical glass fibers. In this research, transparent CaF2 glass-ceramic was prepared by a melt-quenching method. Greatly enhanced upconversion luminescence was observed after heat treatment. By applying a novel method called melt-in-tube, precursor fiber free of crystals was fabricated at the drawing temperature where the clad was softened while the core was melted. Glass-ceramic fiber with fiber core containing Yb3+-Er3+ codoped CaF2 nanocrystals was obtained after heat treatment at a relatively low temperature. Electron probe micro-analyzer measurement shows no obvious element diffusion between the core and clad. Greatly enhanced upconversion emission was detected in the glass-ceramic fiber excited by a 980 nm laser, suggesting the developed glass-ceramic fiber is a promising material for upconversion laser.

  13. Enhanced upconversion emission in crystallization-controllable glass-ceramic fiber containing Yb(3+)-Er(3+) codoped CaF2 nanocrystals.

    PubMed

    Peng, Wencai; Fang, Zaijin; Ma, Zhijun; Qiu, Jianrong

    2016-10-01

    Functional nanocrystal-containing materials have been a hot topic in recent years. However, few researches have focused on functional nanocrystals contained in optical glass fibers. In this research, transparent CaF2 glass-ceramic was prepared by a melt-quenching method. Greatly enhanced upconversion luminescence was observed after heat treatment. By applying a novel method called melt-in-tube, precursor fiber free of crystals was fabricated at the drawing temperature where the clad was softened while the core was melted. Glass-ceramic fiber with fiber core containing Yb(3+)-Er(3+) codoped CaF2 nanocrystals was obtained after heat treatment at a relatively low temperature. Electron probe micro-analyzer measurement shows no obvious element diffusion between the core and clad. Greatly enhanced upconversion emission was detected in the glass-ceramic fiber excited by a 980 nm laser, suggesting the developed glass-ceramic fiber is a promising material for upconversion laser.

  14. Influence of surface coating on structural, morphological and optical properties of upconversion-luminescent LaF3:Yb/Er nanoparticles

    NASA Astrophysics Data System (ADS)

    Ansari, Anees A.; Yadav, Ranvijay; Rai, S. B.

    2016-07-01

    LaF3:Yb/Er (core), LaF3:Yb/Er@LaF3 (core/shell) and LaF3:Yb/Er@LaF3@SiO2 (core/shell/SiO2) nanoparticles were synthesized using citric-acid-based complexation process. X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray analysis, optical absorption, band-gap energy ( E g), Fourier transform infrared and upconversion emission spectroscopy were employed to investigate the structural, morphological and optical properties of the synthesized core and core/shell/SiO2 nanoparticles. These core/shell/SiO2 nanoparticles can be well dispersed in aqueous solvents to form clear colloidal solution. The optical band-gap energy was decreased after shell formation due to increase in the crystalline size. The growth of an inactive and porous silica layers simultaneously on the surface of luminescent core-nanoparticles resulting an increase in average crystalline size of the nanoparticles. As-prepared inert shell-coated core/shell nanoparticles show intensive upconversion-luminescence as compared to the seed-core and silica-surface-modified core/shell/SiO2 nanoparticles because luminescent ions (Yb3+ and Er3+) ions located at the particle surface were protected from the non-radiative decay arising from surface dangling bonds and capping agent. However, our study revealed that there was only a slight reduction in upconversion efficiency for the silica-modified core/shell nanoparticles, indicating that upconversion properties of the upconversion nanoparticles are largely preserved in the core/shell/SiO2 nanoparticles. Absorption and upconversion-luminescence properties were examined for future application in the development of optical devices as well as optical bioprobes.

  15. Luminescence energy transfer detection of PSA in red region based on Mn2+-enhanced NaYF4:Yb, Er upconversion nanorods.

    PubMed

    Zhang, Jianguo; Wang, Shaozhen; Gao, Ni; Feng, Dexiang; Wang, Lun; Chen, Hongqi

    2015-10-15

    A new turn-on luminescence energy transfer (LET) system has been designed for the detection of prostate specific antigen (PSA, a cancer marker) that utilizes Mn(2+)-enhanced long wavelength luminescence NaYF4:Yb, Er upconversion nanorods as the donor and gold nanorods as the acceptor. The Mn(2+)-doped NaYF4:Yb,Er upconversion luminescence nanorods with an emission peak located in the red region were synthesized. The presence of Mn(2+) markedly increased the luminescence intensity over that of the NaYF4:Yb, Er upconversion nanomaterials (excited by a 980 nm continuous wavelength laser). The surfaces of Mn(2+)-doped NaYF4:Yb, Er upconversion nanorods were modified with poly(acrylic acid). Antibodies against prostate specific antigen were bound to the surface of the carboxyl-functionalized upconversion nanorods, which acted as the energy donor in this LET system. Gold nanorods with an absorption band at ~666 nm were synthesized by the seed growth method, acted as the energy acceptor. The emission band of the upconversion nanorods overlapped well with the absorption band of the gold nanorods. The luminescence was quenched because of the electrostatic interactions that shortened the distance between the donor (negatively charged) and the accepter (positively charged).When the PSA antigen was added into the system, the energy acceptor and the energy donors were separated because the binding affinity between PSA and anti-PSA was greater than the electrostatic interactions, and thereby the luminescence was recovered. The linear range of detecting PSA was from 0.1172 to 18.75 ng/mL (R=0.995), with a limit of detection for PSA as low as 0.1129 ng/mL. The method was successfully applied to the sensing of PSA in human serum samples. PMID:25996781

  16. Optical frequency upconversion technique for transmission of wireless MIMO-type signals over optical fiber.

    PubMed

    Shaddad, R Q; Mohammad, A B; Al-Gailani, S A; Al-Hetar, A M

    2014-01-01

    The optical fiber is well adapted to pass multiple wireless signals having different carrier frequencies by using radio-over-fiber (ROF) technique. However, multiple wireless signals which have the same carrier frequency cannot propagate over a single optical fiber, such as wireless multi-input multi-output (MIMO) signals feeding multiple antennas in the fiber wireless (FiWi) system. A novel optical frequency upconversion (OFU) technique is proposed to solve this problem. In this paper, the novel OFU approach is used to transmit three wireless MIMO signals over a 20 km standard single mode fiber (SMF). The OFU technique exploits one optical source to produce multiple wavelengths by delivering it to a LiNbO3 external optical modulator. The wireless MIMO signals are then modulated by LiNbO3 optical intensity modulators separately using the generated optical carriers from the OFU process. These modulators use the optical single-sideband with carrier (OSSB+C) modulation scheme to optimize the system performance against the fiber dispersion effect. Each wireless MIMO signal is with a 2.4 GHz or 5 GHz carrier frequency, 1 Gb/s data rate, and 16-quadrature amplitude modulation (QAM). The crosstalk between the wireless MIMO signals is highly suppressed, since each wireless MIMO signal is carried on a specific optical wavelength.

  17. Increasing electrical conductivity of upconversion materials by in situ binding with graphene

    NASA Astrophysics Data System (ADS)

    Wu, Suli; Sun, Xiaoqian; Zhu, Jiacheng; Chang, Jie; Zhang, Shufen

    2016-08-01

    Upconversion nanoparticles (UCNPs) hold promise as near-infrared light converters to enhance the efficiency of solar cells. However, the prevalent use of UCNPs in solar cells is restricted by their poor electrical conductivity and low emission efficiency. Here reduced graphene oxide (rGO)-NaYF4:Yb3+/Er3+ composites are proposed to achieve good electrical conductivity due to the high charge carrier mobility of rGO. Composites of rGO and UCNPs combined by a chemical bond are in situ synthesized by the hydrothermal method, followed by a reduction process. The contact of UCNPs with rGO is proved by SEM, and the binding between the rGO-UCNP composites is confirmed by Fourier transform infrared spectroscopy. The composites are doped into the photoanode of a solar cell. As anticipated, electrochemical impedance spectroscopy confirms the good electrical conductivity of the in situ synthesized rGO-UCNPs. Furthermore, the use of rGO-UCNPs in solar cells enables an enhancement in short-circuit current density and overall efficiency by about 10%. These findings reveal that the combination of UCNPs with rGO opens up new opportunities of extending the use of UCNPs in the area of solar energy harvesting.

  18. Synthesis of improved upconversion nanoparticles as ultrasensitive fluorescence probe for mycotoxins.

    PubMed

    Chen, Quansheng; Hu, Weiwei; Sun, Cuicui; Li, Huanhuan; Ouyang, Qin

    2016-09-28

    Rare earth-doped upconversion nanoparticles (UCNPs) have promising potentials in biodetection due to their unique frequency upconverting capability and high detection sensitivity. This paper reports an improved UCNPs-based fluorescence probe for dual-sensing of Aflatoxin B1 (AFB1) and Deoxynivalenol (DON) using a magnetism-induced separation and the specific formation of antibody-targets complex. Herein, the improved UCNPs, which were namely NaYF4:Yb/Ho/Gd and NaYF4:Yb/Tm/Gd, were systematically studied based on the optimization of reaction time, temperature and the concentration of dopant ions with simultaneous phase and size controlled NaYF4 nanoparticles; and the targets were detected using the pattern of competitive combination assay. Under an optimized condition, the advanced fluorescent probes revealed stronger fluorescent properties, broader biological applications and better storage stabilities compared to traditional UCNPs-based ones; and ultrasensitive determinations of AFB1 and DON were achieved under a wide sensing range of 0.001-0.1 ng ml(-1) with the limit of detection (LOD) of 0.001 ng ml(-1). Additionally, the applicability of the improved nanosensor for the detection of mycotoxins was also confirmed in adulterated oil samples. PMID:27619096

  19. Synthesis of magnetic and upconversion nanocapsules as multifunctional drug delivery system

    NASA Astrophysics Data System (ADS)

    Huang, Shanshan; Chen, Yinyin; Liu, Bei; He, Fei; Ma, Ping'an; Deng, Xiaoran; Cheng, Ziyong; Lin, Jun

    2015-09-01

    Multifunctional hollow nanocapsules with magnetic and upconversion luminescence properties were synthesized. Hollow Fe3O4@SiO2 was firstly prepared by using rodlike β-FeOOH as the template followed by silica coating, calcinations and reduction. Then Fe3O4@SiO2@α-NaYF4:Yb3+,Er3+ nanocapsules (FeSiUCNP) were synthesized by the hydrothermal transformation of the Y(Yb3+, Er3+)(OH)CO3 (YOC) deposited onto the surface of nanocapsules through a urea-assisted homogeneous precipitation method. The hollow nanocapsules with porous structure provide space and entrance for the drug molecules. Due to the outside shell of α-NaYF4:Yb3+, Er3+, the nanomaterial shows upconverting red emission upon 980 nm NIR-light excitation. Moreover, the nanocomposites with hollow magnetite core exhibit a high relaxivity with r2 value of 183 mM-1 s-1, which reveal the potential as T2-weighted contrast agents for magnetic resonance imaging (MRI). The as-prepared nanocapsules can be performed as anti-cancer drug carriers for investigation of drug loading/release properties, which demonstrated a sustained drug release pattern and a comparable cytotoxicity with free doxorubicin (DOX). The multifunctional nanocapsules incorporated upconverting luminescence, T2-weighted MRI imaging and drug targeting delivery modalities have great potential for theranostic applications in cancer treatment.

  20. Titania coated upconversion nanoparticles for near-infrared light triggered photodynamic therapy.

    PubMed

    Lucky, Sasidharan Swarnalatha; Muhammad Idris, Niagara; Li, Zhengquan; Huang, Kai; Soo, Khee Chee; Zhang, Yong

    2015-01-27

    Because of the limited penetration depth of visible light that generally excites most of the available photosensitizers (PSs), conventional photodynamic therapy (PDT) is limited to the treatment of superficial and flat lesions. Recently, the application of deep penetrating near-infrared (NIR) light excitable upconversion nanoparticles (UCNs) in conjunction with PDT has shown to have clear potential in the treatment of solid tumors due to its ability to penetrate thick tissue. However, various constructs developed so far have certain limitations such as poor or unstable PS loading, reducing their therapeutic efficacy and limiting their application to solution or cell-based studies. In this work, we present a method to fabricate uniform core-shell structured nanoconstruct with a thin layer of photocatalyst or PS-titanium dioxide (TiO2) stably coated on individual UCN core. Our design allows controllable and highly reproducible PS loading, preventing any leakage of PS compared to previously developed nanoconstructs, thus ensuring repeatable PDT results. Further surface modification of the developed nanoconstructs with polyethylene glycol (PEG) rendered them biocompatible, demonstrating good therapeutic efficacy both in vitro and in vivo.

  1. High-Contrast Visualization of Upconversion Luminescence in Mice Using Time-Gating Approach.

    PubMed

    Zheng, Xianlin; Zhu, Xingjun; Lu, Yiqing; Zhao, Jiangbo; Feng, Wei; Jia, Guohua; Wang, Fan; Li, Fuyou; Jin, Dayong

    2016-04-01

    Optical imaging through the near-infrared (NIR) window provides deep penetration of light up to several centimeters into biological tissues. Capable of emitting 800 nm luminescence under 980 nm illumination, the recently developed upconversion nanoparticles (UCNPs) suggest a promising optical contrast agent for in vivo bioimaging. However, presently they require high-power lasers to excite when applied to small animals, leading to significant scattering background that limits the detection sensitivity as well as a detrimental thermal effect. In this work, we show that the time-gating approach implementing pulsed illumination from a NIR diode laser and time-delayed imaging synchronized via an optical chopper offers detection sensitivity more than 1 order of magnitude higher than the conventional approach using optical band-pass filters (S/N, 47321/6353 vs 5339/58), when imaging UCNPs injected into Kunming mice. The pulsed laser illumination (70 μs ON in 200 μs period) also reduces the overall thermal accumulation to 35% of that under the continuous-wave mode. Technical details are given on setting up the time-gating unit comprising an optical chopper, a pinhole, and a microscopy eyepiece. Being generally compatible with any camera, this provides a convenient and low cost solution to NIR animal imaging using UCNPs as well as other luminescent probes.

  2. Optical Frequency Upconversion Technique for Transmission of Wireless MIMO-Type Signals over Optical Fiber

    PubMed Central

    Shaddad, R. Q.; Mohammad, A. B.; Al-Gailani, S. A.; Al-Hetar, A. M.

    2014-01-01

    The optical fiber is well adapted to pass multiple wireless signals having different carrier frequencies by using radio-over-fiber (ROF) technique. However, multiple wireless signals which have the same carrier frequency cannot propagate over a single optical fiber, such as wireless multi-input multi-output (MIMO) signals feeding multiple antennas in the fiber wireless (FiWi) system. A novel optical frequency upconversion (OFU) technique is proposed to solve this problem. In this paper, the novel OFU approach is used to transmit three wireless MIMO signals over a 20 km standard single mode fiber (SMF). The OFU technique exploits one optical source to produce multiple wavelengths by delivering it to a LiNbO3 external optical modulator. The wireless MIMO signals are then modulated by LiNbO3 optical intensity modulators separately using the generated optical carriers from the OFU process. These modulators use the optical single-sideband with carrier (OSSB+C) modulation scheme to optimize the system performance against the fiber dispersion effect. Each wireless MIMO signal is with a 2.4 GHz or 5 GHz carrier frequency, 1 Gb/s data rate, and 16-quadrature amplitude modulation (QAM). The crosstalk between the wireless MIMO signals is highly suppressed, since each wireless MIMO signal is carried on a specific optical wavelength. PMID:24772009

  3. Recombination dynamics in InAsSb quantum-well diode lasers measured using photoluminescence upconversion

    NASA Astrophysics Data System (ADS)

    Cooley, W. T.; Hengehold, R. L.; Yeo, Y. K.; Turner, G. W.; Loehr, J. P.

    1998-11-01

    We report Shockley-Read-Hall (SRH), radiative, and Auger recombination rates in midinfrared laser structures from time-resolved photoluminescence using frequency upconversion. The devices studied were actual InAsSb/InAlAsSb multiple-quantum-well (MQW) diode lasers emitting near 3.3 μm, which have been previously characterized for laser performance. We extend the initial studies and report on the carrier recombination dynamics. The importance of carrier density motivates a careful examination of carrier density and quantum-well effects. SRH, radiative, and Auger recombination rates (ASRH, Brad, and CAuger, respectively) were measured at 77 K and found to be ASRH-1≈10 ns, Brad≈2×10-10 cm3 s-1, and CAuger⩽1.0×10-29 cm6 s-1, respectively. At 150 K the nonradiative recombination coefficients increased to ASRH-1≈1.7 ns, Brad≈0.78×10-10 cm3 s-1 and CAuger≈7.0×10-28 cm6 s-1, respectively. This study suggests InAsSb/InAlAsSb MQW diode laser performance may be limited by SRH nonradiative recombination mechanisms rather than Auger recombination.

  4. Cytotoxic aspects of gadolinium oxide nanostructures for up-conversion and NIR bioimaging.

    PubMed

    Hemmer, Eva; Yamano, Tomoyoshi; Kishimoto, Hidehiro; Venkatachalam, Nallusamy; Hyodo, Hiroshi; Soga, Kohei

    2013-01-01

    Bioimaging is an important diagnostic tool in the investigation and visualization of biological phenomena in cells and in medicine. In this context, up-converting Gd(2)O(3):Er(3+),Yb(3+) nanostructures (nanoparticles, nanorods) have been synthesized by precipitation methods and hydrothermal synthesis. Independent of size and morphology, Gd(2)O(3):Er(3+),Yb(3+) powders show up-conversion (550 nm, 670 nm) and near-infrared emission (1.5 μm) upon 980 nm excitation, which makes these structures interesting for application as biomarkers. With regard to their potential application in bioimaging, cytotoxicity is an important aspect and is strongly affected by the physico-chemical properties of the investigated nanostructures. Therefore, the cytotoxic effect of bare and poly(ethylene glycol)-b-poly(acrylic acid) block co-polymer-modified nanostructures on non-phagocytic and phagocytic cells (B-cell hybridoma cells and macrophages) was investigated. The observed cytotoxic behavior in the case of macrophages incubated with bare nanostructures was assigned to the poor chemical durability of gadolinium oxide, but could be overcome by surface modification.

  5. Upconversion nanosensor for sensitive fluorescence detection of Sudan I-IV based on inner filter effect.

    PubMed

    Fang, Aijin; Long, Qian; Wu, Qiongqiong; Li, Haitao; Zhang, Youyu; Yao, Shouzhuo

    2016-01-01

    Sudan dyes are banned as food additives due to the carcinogenicity of their metabolites in the human body. Therefore, it is of great significance for sensitive detection of Sudan dyes. This paper reports a novel nanosensor for Sudan dyes detection based on fluorescence (FL) quenching of hexadecyl trimethyl ammonium bromide (CTAB) stabilized upconversion nanoparticles (UCNPs) through the inner filter effect (IFE). In the presence of Sudan I-IV, the fluorescence emission of UCNPs was effectively quenched due to the absorption bands of Sudan I-IV largely covered the emission bands of UCNPs. Under the optimized conditions, the FL was quenched with Sudan concentration over the range of 0.05-40, 0.01-20, 0.01-40 and 0.05-40 μg/mL for Sudan I-IV, respectively. The corresponding limit of detection is 15.1, 2.83, 3.52 and 16.7 ng/mL (at 3σ/slope) respectively. Meanwhile, the nanosensor shows good selectivity, sensitivity and can be successfully applied to detection of Sudan in chili powder samples. PMID:26653433

  6. Optimizing the Activation of Chlorin e6 Utilizing Upconversion Energy Transfer

    NASA Astrophysics Data System (ADS)

    Avalos, Julio C.; Pedraza, Francisco J.; Sardar, Dhiraj K.

    2015-03-01

    Current cancer therapy techniques, such as chemotherapy and radiation therapy, possess several drawbacks including lack of selectivity resulting in harmful side effects. Photodynamic therapy (PDT) is one of the fastest emerging techniques due to its many advantages, including the use of nonionizing radiation, targeted delivery, and controlled doses. In PDT, photosensitizers (PSs) are activated inside targeted cells to produce irreversible damage inducing cell death. Since most PSs operate in the visible range, it is difficult to activate them due to the high attenuation of soft tissue. Upconverting nanoparticles (UCNP) are able to absorb in the NIR region, where light is less attenuated, and emit in the visible range, resulting in deeper tissue penetration. UCNPs are able to assist with the activation of the PS by energy transfer when the PS is conjugated onto the UCNP. Chlorin e6 (Ce6) is a commonly used PSs due to its ability to release reactive oxygen species (ROS), which is one of the main processes utilized in PDT. The UCNP studied contain a combination of rare earth doped ions including Erbium, Thulium, and Holmium precisely doped into the host nanocrystal to improve upconversion emission and energy transfer. The work presented will focus on exploring the factors that affect the activation of Ce6. The results will include the enhancement of Ce6 activation and ROS release when conjugated onto a rare earth-doped UCNP. This research was funded by NSF-PREM Grant No. DMR -0934218 and RISE Grant No. GM 060655.

  7. Increasing electrical conductivity of upconversion materials by in situ binding with graphene

    NASA Astrophysics Data System (ADS)

    Wu, Suli; Sun, Xiaoqian; Zhu, Jiacheng; Chang, Jie; Zhang, Shufen

    2016-08-01

    Upconversion nanoparticles (UCNPs) hold promise as near-infrared light converters to enhance the efficiency of solar cells. However, the prevalent use of UCNPs in solar cells is restricted by their poor electrical conductivity and low emission efficiency. Here reduced graphene oxide (rGO)–NaYF4:Yb3+/Er3+ composites are proposed to achieve good electrical conductivity due to the high charge carrier mobility of rGO. Composites of rGO and UCNPs combined by a chemical bond are in situ synthesized by the hydrothermal method, followed by a reduction process. The contact of UCNPs with rGO is proved by SEM, and the binding between the rGO–UCNP composites is confirmed by Fourier transform infrared spectroscopy. The composites are doped into the photoanode of a solar cell. As anticipated, electrochemical impedance spectroscopy confirms the good electrical conductivity of the in situ synthesized rGO–UCNPs. Furthermore, the use of rGO–UCNPs in solar cells enables an enhancement in short-circuit current density and overall efficiency by about 10%. These findings reveal that the combination of UCNPs with rGO opens up new opportunities of extending the use of UCNPs in the area of solar energy harvesting.

  8. Dual enhancement of electroluminescence efficiency and operational stability by rapid upconversion of triplet excitons in OLEDs

    PubMed Central

    Furukawa, Taro; Nakanotani, Hajime; Inoue, Munetomo; Adachi, Chihaya

    2015-01-01

    Recently, triplet harvesting via a thermally activated delayed fluorescence (TADF) process has been established as a realistic route for obtaining ultimate internal electroluminescence (EL) quantum efficiency in organic light-emitting diodes (OLEDs). However, the possibility that the rather long transient lifetime of the triplet excited states would reduce operational stability due to an increased chance for unwarranted chemical reactions has been a concern. Herein, we demonstrate dual enhancement of EL efficiency and operational stability in OLEDs by employing a TADF molecule as an assistant dopant and a fluorescent molecule as an end emitter. The proper combination of assistant dopant and emitter molecules realized a “one-way” rapid Förster energy transfer of singlet excitons from TADF molecules to fluorescent emitters, reducing the number of cycles of intersystem crossing (ISC) and reverse ISC in the TADF molecules and resulting in a significant enhancement of operational stability compared to OLEDs with a TADF molecule as the end emitter. In addition, we found that the presence of this rapid energy transfer significantly suppresses singlet-triplet annihilation. Using this finely-tuned rapid triplet-exciton upconversion scheme, OLED performance and lifetime was greatly improved. PMID:25673259

  9. Upconversion Nanoparticle-Based Förster Resonance Energy Transfer for Detecting DNA Methylation.

    PubMed

    Kim, Seockjune; Hwang, Sang-Hyun; Im, Su-Gyeong; Lee, Min-Ki; Lee, Chang-Hun; Son, Sang Jun; Oh, Heung-Bum

    2016-01-01

    Aberrant methylation of a crucial CpG island is the main mechanism for the inactivation of CDKN2A in the early stages of carcinogenesis. Therefore, the detection of DNA methylation with high sensitivity and specificity is important, and various detection methods have been developed. Recently, upconversion nanoparticles (UCNPs) have been found to display a high signal-to-noise ratio and no photobleaching, making them useful for diagnostic applications. In this pilot study, we applied UCNPs to the detection of CDKN2A methylation and evaluated the feasibility of this system for use in molecular diagnostics. DNA PCR was performed using biotinylated primers, and the PCR amplicon was then intercalated with SYTOX Orange dye, followed by incubation with streptavidin-conjugated UCNPs. Fluorescence detection of the Förster resonance energy transfer (FRET) of the UCNPs (MS-UC-FRET) was then performed, and the results were compared to those from real-time PCR (RQ-PCR) and pyrosequencing. Detection by MS-UC-FRET was more sensitive than that by either RQ-PCR or pyrosequencing. Our results confirmed the success of our MS-UC-FRET system for detecting DNA methylation and demonstrated the potential application of this system in molecular diagnostics. PMID:27517925

  10. Controllable self-assembly of NaREF4 upconversion nanoparticles and their distinctive fluorescence properties

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoxia; Ni, Yaru; Zhu, Cheng; Fang, Liang; Kou, Jiahui; Lu, Chunhua; Xu, Zhongzi

    2016-07-01

    The paper presents the growth of hexagonal NaYF4:Yb3+, Tm3+ nanocrystals with tunable sizes induced by different contents of doped Yb3+ ions (10%–99.5%) using the thermal decomposition method. These nanoparticles, which have different sizes, are then self-assembled at the interface of cyclohexane and ethylene and transferred onto a normal glass slide. It is found that the size of nanoparticles directs their self-assembly. Due to the appropriate size of 40.5 nm, 15% Yb3+ ions doped nanoparticles are able to be self-assembled into an ordered inorganic monolayer membrane with a large area of about 10 × 10 μm2. More importantly, the obvious short-wave (300–500 nm) fluorescence improvement of the ordered 2D self-assembly structure is observed to be relative to disordered nanoparticles, which is because intrinsic absorption and scattering of upconversion nanoparticles leads to the self-loss of fluorescence, especially the short-wave fluorescence inside the disordered structure, and the relative emission of short-wave fluorescence is reduced. The construction of a 2D self-assembly structure can effectively avoid this and improve the radiated short-wave fluorescence, especially UV photons, and is able to direct the design of new types of solid-state optical materials in many fields.

  11. Instantaneous ballistic velocity of suspended Brownian nanocrystals measured by upconversion nanothermometry

    NASA Astrophysics Data System (ADS)

    Brites, Carlos D. S.; Xie, Xiaoji; Debasu, Mengistie L.; Qin, Xian; Chen, Runfeng; Huang, Wei; Rocha, João; Liu, Xiaogang; Carlos, Luís D.

    2016-10-01

    Brownian motion is one of the most fascinating phenomena in nature. Its conceptual implications have a profound impact in almost every field of science and even economics, from dissipative processes in thermodynamic systems, gene therapy in biomedical research, artificial motors and galaxy formation to the behaviour of stock prices. However, despite extensive experimental investigations, the basic microscopic knowledge of prototypical systems such as colloidal particles in a fluid is still far from being complete. This is particularly the case for the measurement of the particles' instantaneous velocities, elusive due to the rapid random movements on extremely short timescales. Here, we report the measurement of the instantaneous ballistic velocity of Brownian nanocrystals suspended in both aqueous and organic solvents. To achieve this, we develop a technique based on upconversion nanothermometry. We find that the population of excited electronic states in NaYF4:Yb/Er nanocrystals at thermal equilibrium can be used for temperature mapping of the nanofluid with great thermal sensitivity (1.15% K‑1 at 296 K) and a high spatial resolution (<1 μm). A distinct correlation between the heat flux in the nanofluid and the temporal evolution of Er3+ emission allows us to measure the instantaneous velocity of nanocrystals with different sizes and shapes.

  12. Upconversion luminescence resonance energy transfer-based aptasensor for the sensitive detection of oxytetracycline.

    PubMed

    Zhang, Hui; Fang, Congcong; Wu, Shijia; Duan, Nuo; Wang, Zhouping

    2015-11-15

    In this work, a biosensor based on luminescence resonance energy transfer (LRET) from NaYF4:Yb,Tm upconversion nanoparticles (UCNPs) to SYBR Green I has been developed. The aptamers are covalently linked to UCNPs and hybridized with their complementary strands. The subsequent addition of SYBR Green allows SYBR Green I to insert into the formed double-stranded DNA (dsDNA) duplex and brings the energy donor and acceptor into close proximity, leading to the fluorescence of UCNPs transferred to SYBR Green I. When excited at 980 nm, the UCNPs emit luminescence at 477 nm, and this energy is transferred to SYBR Green I, which emits luminescence at 530 nm. In the presence of oxytetracycline (OTC), the aptamers prefer to bind to its corresponding analyte and dehybridize with the complementary DNA. This dehybridization leads to the liberation of SYBR Green I, which distances SYBR Green I from the UCNPs and recovers the UCNPs' luminescence. Under optimal conditions, a linear calibration is obtained between the ratio of I530 to I477 nm (I530/I477) and the OTC concentration, which ranges from 0.1 to 10 ng/ml with a limit of detection (LOD) of 0.054 ng/ml. PMID:26302361

  13. Realization of a video-rate distributed aperture millimeter-wave imaging system using optical upconversion

    NASA Astrophysics Data System (ADS)

    Schuetz, Christopher; Martin, Richard; Dillon, Thomas; Yao, Peng; Mackrides, Daniel; Harrity, Charles; Zablocki, Alicia; Shreve, Kevin; Bonnett, James; Curt, Petersen; Prather, Dennis

    2013-05-01

    Passive imaging using millimeter waves (mmWs) has many advantages and applications in the defense and security markets. All terrestrial bodies emit mmW radiation and these wavelengths are able to penetrate smoke, fog/clouds/marine layers, and even clothing. One primary obstacle to imaging in this spectrum is that longer wavelengths require larger apertures to achieve the resolutions desired for many applications. Accordingly, lens-based focal plane systems and scanning systems tend to require large aperture optics, which increase the achievable size and weight of such systems to beyond what can be supported by many applications. To overcome this limitation, a distributed aperture detection scheme is used in which the effective aperture size can be increased without the associated volumetric increase in imager size. This distributed aperture system is realized through conversion of the received mmW energy into sidebands on an optical carrier. This conversion serves, in essence, to scale the mmW sparse aperture array signals onto a complementary optical array. The side bands are subsequently stripped from the optical carrier and recombined to provide a real time snapshot of the mmW signal. Using this technique, we have constructed a real-time, video-rate imager operating at 75 GHz. A distributed aperture consisting of 220 upconversion channels is used to realize 2.5k pixels with passive sensitivity. Details of the construction and operation of this imager as well as field testing results will be presented herein.

  14. Recent Advances in Upconversion Nanoparticles-Based Multifunctional Nanocomposites for Combined Cancer Therapy.

    PubMed

    Tian, Gan; Zhang, Xiao; Gu, Zhanjun; Zhao, Yuliang

    2015-12-16

    Lanthanide-doped upconversion nanoparticles (UCNPs) have the ability to generate ultraviolet or visible emissions under continuous-wave near-infrared (NIR) excitation. Utilizing this special luminescence property, UCNPs are approved as a new generation of contrast agents in optical imaging with deep tissue-penetration ability and high signal-to-noise ratio. The integration of UCNPs with other functional moieties can endow them with highly enriched functionalities for imaging-guided cancer therapy, which makes composites based on UCNPs emerge as a new class of theranostic agents in biomedicine. Here, recent progress in combined cancer therapy using functional nanocomposites based on UCNPs is reviewed. Combined therapy referring to the co-delivery of two or more therapeutic agents or a combination of different treatments is becoming more popular in clinical treatment of cancer because it generates synergistic anti-cancer effects, reduces individual drug-related toxicity and suppresses multi-drug resistance through different mechanisms of action. Here, the recent advances of combined therapy contributed by UCNPs-based nanocomposites on two main branches are reviewed: i) photodynamic therapy and ii) chemotherapy, which are the two most widely adopted therapies of UCNPs-based composites. The future prospects and challenges in this emerging field will be also discussed.

  15. An Anion-Induced Hydrothermal Oriented-Explosive Strategy for the Synthesis of Porous Upconversion Nanocrystals

    PubMed Central

    Qiu, Peiyu; Sun, Rongjin; Gao, Guo; Zhang, Chunlei; Chen, Bin; Yan, Naishun; Yin, Ting; Liu, Yanlei; Zhang, Jingjing; Yang, Yao; Cui, Daxiang

    2015-01-01

    Rare-earth (RE)-doped upconversion nanocrystals (UCNCs) are deemed as the promising candidates of luminescent nanoprobe for biological imaging and labeling. A number of methods have been used for the fabrication of UCNCs, but their assembly into porous architectures with desired size, shape and crystallographic phase remains a long-term challenging task. Here we report a facile, anion-induced hydrothermal oriented-explosive method to simultaneously control size, shape and phase of porous UCNCs. Our results confirmed the anion-induced hydrothermal oriented-explosion porous structure, size and phase transition for the cubic/hexagonal phase of NaLuF4 and NaGdF4 nanocrystals with various sizes and shapes. This general method is very important not only for successfully preparing lanthanide doped porous UCNCs, but also for clarifying the formation process of porous UCNCs in the hydrothermal system. The synthesized UCNCs were used for in vitro and in vivo CT imaging, and could be acted as the potential CT contrast agents. PMID:25767613

  16. High-Performance Upconversion Nanoprobes for Multimodal MR Imaging of Acute Ischemic Stroke.

    PubMed

    Wang, Jing; Zhang, Hua; Ni, Dalong; Fan, Wenpei; Qu, Jianxun; Liu, Yanyan; Jin, Yingying; Cui, Zhaowen; Xu, Tianyong; Wu, Yue; Bu, Wenbo; Yao, Zhenwei

    2016-07-01

    Multimodal magnetic resonance (MR) imaging, including MR angiography (MRA) and MR perfusion (MRP), plays a critical role in the diagnosis and surveillance of acute ischemic stroke. However, these techniques are hindered by the low T1 relaxivity, short circulation time, and high leakage rate from vessels of clinical Magnevist. To address these problems, nontoxic polyethylene glycol (PEG)ylated upconversion nanoprobes (PEG-UCNPs) are synthesized and first adopted for excellent MRA and MRP imaging, featuring high diagnostic sensitivity toward acute ischemic stroke in high-resolution imaging. The investigations show that the agent possesses superior advantages over clinical Magnevist, such as much higher relaxivity, longer circulation time, and lower leakage rate, which guarantee much better imaging efficiency. Remarkably, an extremely small dosage (5 mg Gd kg(-1) ) of PEG-UCNPs provides high-resolution MRA imaging with the vascular system delineated much clearer than the Magnevist with clinical dosage as high as 108 mg Gd kg(-1) . On the other hand, the long circulation time of PEG-UCNPs enables the surveillance of the progression of ischemic stroke using MRA or MRP. Once translated, these PEG-UCNPs are expected to be a promising candidate for substituting the clinical Magnevist in MRA and MRP, which will significantly lengthen the imaging time window and improve the overall diagnostic efficiency. PMID:27219071

  17. Upconversion fluorescent nanoparticles as a potential tool for in-depth imaging

    NASA Astrophysics Data System (ADS)

    Nagarajan, Sounderya; Zhang, Yong

    2011-09-01

    Upconversion nanoparticles (UCNs) are nanoparticles that are excited in the near infrared (NIR) region with emission in the visible or NIR regions. This makes these particles attractive for use in biological imaging as the NIR light can penetrate the tissue better with minimal absorption/scattering. This paper discusses the study of the depth to which cells can be imaged using these nanoparticles. UCNs with NaYF4 nanocrystals doped with Yb3 + , Er3 + (visible emission)/Yb3 + , Tm3 + (NIR emission) were synthesized and modified with silica enabling their dispersion in water and conjugation of biomolecules to their surface. The size of the sample was characterized using transmission electron microscopy and the fluorescence measured using a fluorescence spectrometer at an excitation of 980 nm. Tissue phantoms were prepared by reported methods to mimic skin/muscle tissue and it was observed that the cells could be imaged up to a depth of 3 mm using the NIR emitting UCNs. Further, the depth of detection was evaluated for UCNs targeted to gap junctions formed between cardiac cells.

  18. Temperature-feedback upconversion nanocomposite for accurate photothermal therapy at facile temperature.

    PubMed

    Zhu, Xingjun; Feng, Wei; Chang, Jian; Tan, Yan-Wen; Li, Jiachang; Chen, Min; Sun, Yun; Li, Fuyou

    2016-01-01

    Photothermal therapy (PTT) at present, following the temperature definition for conventional thermal therapy, usually keeps the temperature of lesions at 42-45 °C or even higher. Such high temperature kills cancer cells but also increases the damage of normal tissues near lesions through heat conduction and thus brings about more side effects and inhibits therapeutic accuracy. Here we use temperature-feedback upconversion nanoparticle combined with photothermal material for real-time monitoring of microscopic temperature in PTT. We observe that microscopic temperature of photothermal material upon illumination is high enough to kill cancer cells when the temperature of lesions is still low enough to prevent damage to normal tissue. On the basis of the above phenomenon, we further realize high spatial resolution photothermal ablation of labelled tumour with minimal damage to normal tissues in vivo. Our work points to a method for investigating photothermal properties at nanoscale, and for the development of new generation of PTT strategy. PMID:26842674

  19. Temperature-Sensing Behavior Based on Upconversion Luminescence at the Rhombohedral-Tetragonal Phase Boundary

    NASA Astrophysics Data System (ADS)

    Zou, Hua; Hu, Yifeng; Zhu, Xiaoqin; Zhang, Jianhao; Wang, Xusheng; Song, Zhitang

    2016-10-01

    In this work, (1- x)(K0.48Na0.52)(Nb0.95Sb0.05)O3- x - xEr0.5(Na0.82K0.18)0.5ZrO3 ( x = 0-0.05) ceramics were fabricated by solid-state reaction techniques. The rhombohedral-tetragonal (R-T) phase boundary of the ceramics was identified at 0.04 ≤ x, thus providing an opportunity to investigate the upconversion emission derived from the Er3+ ions at the R-T phase boundary. Under 980 nm laser excitation, the R-T phase ceramics exhibited a strong green emission. In addition, the fluorescence intensity ratios of green emissions at 530 nm and 550 nm were investigated in a temperature range of 180-510 K, and maximum sensing sensitivity was found to be 0.0037 K-1. The results indicate that Er3+-doped ceramics with R-T phase boundaries can be applied to new multifunctional electro-optical temperature sensors. Laser excitation heating effects were also observed in detail.

  20. Nonlinear modeling of low-to-high-frequency noise up-conversion in microwave electron devices

    NASA Astrophysics Data System (ADS)

    Filicori, Fabio; Traverso, Pier A.; Florian, Corrado

    2003-05-01

    Measurement-based, circuit-oriented non-linear noise modeling of microwave electron devices is still an open field of research, since existing approaches are not always suitable for the accurate prediction of low-frequency noise up-conversion to RF, which represents an essential information for the non-linear circuit analyses performed in the CAD of low phase-noise oscillators. In this paper a technology-independent, empirical approach to the modeling of noise contributions at the ports of electron devices, operating under strongly non-linear conditions, is proposed. Details concerning the analytical formulation of the model, which is derived by considering randomly time-varying perturbations in the basic equations of an otherwise conventional charge-controlled non-linear model, are presented, along with a discussion about the measurement techniques devoted to its experimental characterization. An example of application of the proposed Charge-Controlled Non-linear Noise (CCNN) model is considered in the case of a HBT transistor. Techniques devoted to the implementation of the obtained model in the framework of commercial CAD tools for circuit analysis and design are provided as well.

  1. Lanthanide‐Doped Upconversion Nanoparticles: Emerging Intelligent Light‐Activated Drug Delivery Systems

    PubMed Central

    Bagheri, Ali; Arandiyan, Hamidreza

    2016-01-01

    The development of drug delivery systems (DDSs) using near infrared (NIR) light and upconversion nanoparticles (UCNPs) has generated intensive interest over the past five years. These NIR‐initiated DDSs not only offer a high degree of spatial and temporal determination of therapeutic release but also provide precise control over the released dosage. Furthermore, these nanoplatforms confer several advantages over conventional light‐based DDSs—NIR offers better tissue penetration depth and a reduced risk of cellular photo‐damage caused by exposure to light at high‐energy wavelengths (e.g., ultraviolet light, <400 nm). The development of DDSs that can be activated by low intensity NIR illumination is highly desirable to avoid exposing living tissues to excessive heat that can limit the in vivo application of these DDSs. This encompasses research in three directions: (i) enhancing the quantum yield of the UCNPs; (ii) incorporation of photo‐responsive materials with red‐shifted absorptions into the UCNPs; and (iii) tuning the UCNPs excitation wavelength. This review focuses on recent advances in the development of NIR‐initiated DDS, with emphasis on the use of photo‐responsive compounds and polymeric materials conjugated onto UCNPs. The challenges that limit UCNPs clinical applications, alongside with the aforementioned techniques that have emerged to overcome these limitations, are highlighted.

  2. Controllable self-assembly of NaREF4 upconversion nanoparticles and their distinctive fluorescence properties.

    PubMed

    Liu, Xiaoxia; Ni, Yaru; Zhu, Cheng; Fang, Liang; Kou, Jiahui; Lu, Chunhua; Xu, Zhongzi

    2016-07-22

    The paper presents the growth of hexagonal NaYF4:Yb(3+), Tm(3+) nanocrystals with tunable sizes induced by different contents of doped Yb(3+) ions (10%-99.5%) using the thermal decomposition method. These nanoparticles, which have different sizes, are then self-assembled at the interface of cyclohexane and ethylene and transferred onto a normal glass slide. It is found that the size of nanoparticles directs their self-assembly. Due to the appropriate size of 40.5 nm, 15% Yb(3+) ions doped nanoparticles are able to be self-assembled into an ordered inorganic monolayer membrane with a large area of about 10 × 10 μm(2). More importantly, the obvious short-wave (300-500 nm) fluorescence improvement of the ordered 2D self-assembly structure is observed to be relative to disordered nanoparticles, which is because intrinsic absorption and scattering of upconversion nanoparticles leads to the self-loss of fluorescence, especially the short-wave fluorescence inside the disordered structure, and the relative emission of short-wave fluorescence is reduced. The construction of a 2D self-assembly structure can effectively avoid this and improve the radiated short-wave fluorescence, especially UV photons, and is able to direct the design of new types of solid-state optical materials in many fields.

  3. All-fiber upconversion high spectral resolution wind lidar using a Fabry-Perot interferometer.

    PubMed

    Shangguan, Mingjia; Xia, Haiyun; Wang, Chong; Qiu, Jiawei; Shentu, Guoliang; Zhang, Qiang; Dou, Xiankang; Pan, Jian-Wei

    2016-08-22

    An all-fiber, micro-pulse and eye-safe high spectral resolution wind lidar (HSRWL) at 1.5 μm is proposed and demonstrated by using a pair of upconversion single-photon detectors and a fiber Fabry-Perot scanning interferometer (FFP-SI). In order to improve the optical detection efficiency, both the transmission spectrum and the reflection spectrum of the FFP-SI are used for spectral analyses of the aerosol backscatter and the reference laser pulse. Taking advantages of high signal-to-noise ratio of the detectors and high spectral resolution of the FFP-SI, the center frequencies and the bandwidths of spectra of the aerosol backscatter are obtained simultaneously. Continuous LOS wind observations are carried out on two days at Hefei (31.843 °N, 117.265 °E), China. The horizontal detection range of 4 km is realized with temporal resolution of 1 minute. The spatial resolution is switched from 30 m to 60 m at distance of 1.8 km. In a comparison experiment, LOS wind measurements from the HSRWL show good agreement with the results from an ultrasonic wind sensor (Vaisala windcap WMT52). An empirical method is adopted to evaluate the precision of the measurements. The standard deviation of the wind speed is 0.76 m/s at 1.8 km. The standard deviation of bandwidth variation is 2.07 MHz at 1.8 km.

  4. Upconversion luminescence resonance energy transfer-based aptasensor for the sensitive detection of oxytetracycline.

    PubMed

    Zhang, Hui; Fang, Congcong; Wu, Shijia; Duan, Nuo; Wang, Zhouping

    2015-11-15

    In this work, a biosensor based on luminescence resonance energy transfer (LRET) from NaYF4:Yb,Tm upconversion nanoparticles (UCNPs) to SYBR Green I has been developed. The aptamers are covalently linked to UCNPs and hybridized with their complementary strands. The subsequent addition of SYBR Green allows SYBR Green I to insert into the formed double-stranded DNA (dsDNA) duplex and brings the energy donor and acceptor into close proximity, leading to the fluorescence of UCNPs transferred to SYBR Green I. When excited at 980 nm, the UCNPs emit luminescence at 477 nm, and this energy is transferred to SYBR Green I, which emits luminescence at 530 nm. In the presence of oxytetracycline (OTC), the aptamers prefer to bind to its corresponding analyte and dehybridize with the complementary DNA. This dehybridization leads to the liberation of SYBR Green I, which distances SYBR Green I from the UCNPs and recovers the UCNPs' luminescence. Under optimal conditions, a linear calibration is obtained between the ratio of I530 to I477 nm (I530/I477) and the OTC concentration, which ranges from 0.1 to 10 ng/ml with a limit of detection (LOD) of 0.054 ng/ml.

  5. Systematic assessment of blood circulation time of functionalized upconversion nanoparticles in the chick embryo

    NASA Astrophysics Data System (ADS)

    Nadort, Annemarie; Liang, Liuen; Grebenik, Ekaterina; Guller, Anna; Lu, Yiqing; Qian, Yi; Goldys, Ewa; Zvyagin, Andrei

    2015-12-01

    Nanoparticle-based delivery of drugs and contrast agents holds great promise in cancer research, because of the increased delivery efficiency compared to `free' drugs and dyes. A versatile platform to investigate nanotechnology is the chick embryo chorioallantoic membrane tumour model, due to its availability (easy, cheap) and accessibility (interventions, imaging). In our group, we developed this model using several tumour cell lines (e.g. breast cancer, colon cancer). In addition, we have synthesized in-house silica coated photoluminescent upconversion nanoparticles with several functional groups (COOH, NH2, PEG). In this work we will present the systematic assessment of their in vivo blood circulation times. To this end, we injected chick embryos grown ex ovo with the functionalized UCNPs and obtained a small amount of blood at several time points after injection to create blood smears The UCNP signal from the blood smears was quantified using a modified inverted microscope imaging set-up. The results of this systematic study are valuable to optimize biochemistry protocols and guide nanomedicine advancement in the versatile chick embryo tumour model.

  6. Upconversion luminescence of CsScF4 crystals doped with erbium and ytterbium

    NASA Astrophysics Data System (ADS)

    Ikonnikov, D. A.; Voronov, V. N.; Molokeev, M. S.; Aleksandrovsky, A. S.

    2016-10-01

    Tetragonal CsScF4 crystals doped with (5 at.%) Er and Er/Yb (0.5 at.%/5 at.%) are grown and their crystal structure is determined to belong to Pmmn space group. Er and Yb ions are shown to occupy distorted octahedral Sc sites with the center of inversion. Bright visible upconversion luminescence was observed under 970-980 nm pumping with red (4F9/2), yellow (4S3/2) and green (2H11/2) bands of comparable intensity. UCL tuning curves maximize at 972 nm (CSF:Er) and at 969.7 nm (CSF:Er,Yb) pumping wavelengths. Different ratios between yellow-green and red luminescence intensities in CSF:Er and CSF:Er, Yb are explained by contribution of cross-relaxation in CSF:Er UCL. UC in CSF:Er is a three stage process while UC in CSF:Er, Yb is a two stage process. The peculiarities of power dependences are explained by the power-dependent repopulation between starting levels of UC.

  7. Simultaneous aptasensor for multiplex pathogenic bacteria detection based on multicolor upconversion nanoparticles labels.

    PubMed

    Wu, Shijia; Duan, Nuo; Shi, Zhao; Fang, Congcong; Wang, Zhouping

    2014-03-18

    A highly sensitive and specific multiplex method for the simultaneous detection of three pathogenic bacteria was fabricated using multicolor upconversion nanoparticles (UCNPs) as luminescence labels coupled with aptamers as the molecular recognition elements. Multicolor UCNPs were synthesized via doping with various rare-earth ions to obtain well-separated emission peaks. The aptamer sequences were selected using the systematic evolution of ligands by exponential enrichment (SELEX) strategy for Staphylococcus aureus, Vibrio parahemolyticus, and Salmonella typhimurium. When applied in this method, aptamers can be used for the specific recognition of the bacteria from complex mixtures, including those found in real food matrixes. Aptamers and multicolor UCNPs were employed to selectively capture and simultaneously quantify the three target bacteria on the basis of the independent peaks. Under optimal conditions, the correlation between the concentration of three bacteria and the luminescence signal was found to be linear from 50-10(6) cfu mL(-1). Improved by the magnetic separation and concentration effect of Fe3O4 magnetic nanoparticles, the limits of detection of the developed method were found to be 25, 10, and 15 cfu mL(-1) for S. aureus, V. parahemolyticus, and S. typhimurium, respectively. The capability of the bioassay in real food samples was also investigated, and the results were consistent with experimental results obtained from plate-counting methods. This proposed method for the detection of various pathogenic bacteria based on multicolor UCNPs has great potential in the application of food safety and multiplex nanosensors. PMID:24568625

  8. Temperature-feedback upconversion nanocomposite for accurate photothermal therapy at facile temperature

    PubMed Central

    Zhu, Xingjun; Feng, Wei; Chang, Jian; Tan, Yan-Wen; Li, Jiachang; Chen, Min; Sun, Yun; Li, Fuyou

    2016-01-01

    Photothermal therapy (PTT) at present, following the temperature definition for conventional thermal therapy, usually keeps the temperature of lesions at 42–45 °C or even higher. Such high temperature kills cancer cells but also increases the damage of normal tissues near lesions through heat conduction and thus brings about more side effects and inhibits therapeutic accuracy. Here we use temperature-feedback upconversion nanoparticle combined with photothermal material for real-time monitoring of microscopic temperature in PTT. We observe that microscopic temperature of photothermal material upon illumination is high enough to kill cancer cells when the temperature of lesions is still low enough to prevent damage to normal tissue. On the basis of the above phenomenon, we further realize high spatial resolution photothermal ablation of labelled tumour with minimal damage to normal tissues in vivo. Our work points to a method for investigating photothermal properties at nanoscale, and for the development of new generation of PTT strategy. PMID:26842674

  9. Observation of Considerable Upconversion Enhancement Induced by Cu2-xS Plasmon Nanoparticles.

    PubMed

    Zhou, Donglei; Liu, Dali; Xu, Wen; Yin, Ze; Chen, Xu; Zhou, Pingwei; Cui, Shaobo; Chen, Zhanguo; Song, Hongwei

    2016-05-24

    Localized surface plasmon resonances (LSPRs) are achieved in heavily doped semiconductor nanoparticles (NPs) with appreciable free carrier concentrations. In this paper, we present the photonic, electric, and photoelectric properties of plasmonic Cu2-xS NPs/films and the utilization of LSPRs generated from semiconductor NPs as near-infrared antennas to enhance the upconversion luminescence (UCL) of NaYF4:Yb(3+),Er(3+) NPs. Our results suggest that the LSPRs in Cu2-xS NPs originate from ligand-confined carriers and that a heat treatment resulted in the decomposition of ligands and oxidation of Cu2-xS NPs; these effects led to a decrease of the Cu(2+)/Cu(+) ratio, which in turn resulted in the broadening, decrease in intensity, and red-shift of the LSPRs. In the presence of a MoO3 spacer, the UCL intensity of NaYF4:Yb(3+),Er(3+) NPs was substantially improved and exhibited extraordinary power-dependent behavior because of the energy band structure of the Cu2-xS semiconductor. These findings provide insights into the nature of LSPR in semiconductors and their interaction with nearby emitters and highlight the possible application of LSPR in photonic and photoelectric devices.

  10. Simultaneous aptasensor for multiplex pathogenic bacteria detection based on multicolor upconversion nanoparticles labels.

    PubMed

    Wu, Shijia; Duan, Nuo; Shi, Zhao; Fang, Congcong; Wang, Zhouping

    2014-03-18

    A highly sensitive and specific multiplex method for the simultaneous detection of three pathogenic bacteria was fabricated using multicolor upconversion nanoparticles (UCNPs) as luminescence labels coupled with aptamers as the molecular recognition elements. Multicolor UCNPs were synthesized via doping with various rare-earth ions to obtain well-separated emission peaks. The aptamer sequences were selected using the systematic evolution of ligands by exponential enrichment (SELEX) strategy for Staphylococcus aureus, Vibrio parahemolyticus, and Salmonella typhimurium. When applied in this method, aptamers can be used for the specific recognition of the bacteria from complex mixtures, including those found in real food matrixes. Aptamers and multicolor UCNPs were employed to selectively capture and simultaneously quantify the three target bacteria on the basis of the independent peaks. Under optimal conditions, the correlation between the concentration of three bacteria and the luminescence signal was found to be linear from 50-10(6) cfu mL(-1). Improved by the magnetic separation and concentration effect of Fe3O4 magnetic nanoparticles, the limits of detection of the developed method were found to be 25, 10, and 15 cfu mL(-1) for S. aureus, V. parahemolyticus, and S. typhimurium, respectively. The capability of the bioassay in real food samples was also investigated, and the results were consistent with experimental results obtained from plate-counting methods. This proposed method for the detection of various pathogenic bacteria based on multicolor UCNPs has great potential in the application of food safety and multiplex nanosensors.

  11. Upconversion effective enhancement by producing various coordination surroundings of rare-Earth ions.

    PubMed

    Huang, Qingming; Yu, Han; Ma, En; Zhang, Xinqi; Cao, Wenbing; Yang, Chengang; Yu, Jianchang

    2015-03-16

    In this manuscript, we present a simple route to enhance upconversion (UC) emission by producing two different coordination sites of trivalent cations in a matrix material and adjusting crystal field asymmetry by Hf(4+) co-doping. A cubic phase, Y3.2Al0.32Yb0.4Er0.08F12, with these structural characteristics was synthesized successfully by introducing a small ion (Al(3+)) into YF3. X-ray diffraction (XRD), nuclear magnetic resonance (NMR), transmission electron microscopy (TEM), X-ray spectroscopy (XPS), and fluorescence spectrophotometry (FS) were employed for its crystalline structure and luminescent property analysis. As a result, the coordination environments of the rare-earth ions were varied more obviously than a hexagonal NaYF4 matrix with the same Hf(4+) co-doping concentration, with vertical comparison, UC luminescent intensities of cubic Y3.2Al0.32Yb0.4Er0.08F12 were largely enhanced (∼32-80 times greater than that of different band emissions), while the maximum enhancement of hexagonal NaYF4 was by a factor of ∼12. According to our experimental results, the mechanism has been demonstrated involving the crystalline structure, crystal field asymmetry, luminescence lifetime, hypersensitive transition, and so on. The study may be helpful for the design and fabrication of high-performance UC materials.

  12. Upconversion Nanoparticle-Based Förster Resonance Energy Transfer for Detecting DNA Methylation

    PubMed Central

    Kim, Seockjune; Hwang, Sang-Hyun; Im, Su-Gyeong; Lee, Min-Ki; Lee, Chang-Hun; Son, Sang Jun; Oh, Heung-Bum

    2016-01-01

    Aberrant methylation of a crucial CpG island is the main mechanism for the inactivation of CDKN2A in the early stages of carcinogenesis. Therefore, the detection of DNA methylation with high sensitivity and specificity is important, and various detection methods have been developed. Recently, upconversion nanoparticles (UCNPs) have been found to display a high signal-to-noise ratio and no photobleaching, making them useful for diagnostic applications. In this pilot study, we applied UCNPs to the detection of CDKN2A methylation and evaluated the feasibility of this system for use in molecular diagnostics. DNA PCR was performed using biotinylated primers, and the PCR amplicon was then intercalated with SYTOX Orange dye, followed by incubation with streptavidin-conjugated UCNPs. Fluorescence detection of the Förster resonance energy transfer (FRET) of the UCNPs (MS-UC-FRET) was then performed, and the results were compared to those from real-time PCR (RQ-PCR) and pyrosequencing. Detection by MS-UC-FRET was more sensitive than that by either RQ-PCR or pyrosequencing. Our results confirmed the success of our MS-UC-FRET system for detecting DNA methylation and demonstrated the potential application of this system in molecular diagnostics. PMID:27517925

  13. Observation of Considerable Upconversion Enhancement Induced by Cu2-xS Plasmon Nanoparticles.

    PubMed

    Zhou, Donglei; Liu, Dali; Xu, Wen; Yin, Ze; Chen, Xu; Zhou, Pingwei; Cui, Shaobo; Chen, Zhanguo; Song, Hongwei

    2016-05-24

    Localized surface plasmon resonances (LSPRs) are achieved in heavily doped semiconductor nanoparticles (NPs) with appreciable free carrier concentrations. In this paper, we present the photonic, electric, and photoelectric properties of plasmonic Cu2-xS NPs/films and the utilization of LSPRs generated from semiconductor NPs as near-infrared antennas to enhance the upconversion luminescence (UCL) of NaYF4:Yb(3+),Er(3+) NPs. Our results suggest that the LSPRs in Cu2-xS NPs originate from ligand-confined carriers and that a heat treatment resulted in the decomposition of ligands and oxidation of Cu2-xS NPs; these effects led to a decrease of the Cu(2+)/Cu(+) ratio, which in turn resulted in the broadening, decrease in intensity, and red-shift of the LSPRs. In the presence of a MoO3 spacer, the UCL intensity of NaYF4:Yb(3+),Er(3+) NPs was substantially improved and exhibited extraordinary power-dependent behavior because of the energy band structure of the Cu2-xS semiconductor. These findings provide insights into the nature of LSPR in semiconductors and their interaction with nearby emitters and highlight the possible application of LSPR in photonic and photoelectric devices. PMID:27149281

  14. Increasing electrical conductivity of upconversion materials by in situ binding with graphene.

    PubMed

    Wu, Suli; Sun, Xiaoqian; Zhu, Jiacheng; Chang, Jie; Zhang, Shufen

    2016-08-26

    Upconversion nanoparticles (UCNPs) hold promise as near-infrared light converters to enhance the efficiency of solar cells. However, the prevalent use of UCNPs in solar cells is restricted by their poor electrical conductivity and low emission efficiency. Here reduced graphene oxide (rGO)-NaYF4:Yb(3+)/Er(3+) composites are proposed to achieve good electrical conductivity due to the high charge carrier mobility of rGO. Composites of rGO and UCNPs combined by a chemical bond are in situ synthesized by the hydrothermal method, followed by a reduction process. The contact of UCNPs with rGO is proved by SEM, and the binding between the rGO-UCNP composites is confirmed by Fourier transform infrared spectroscopy. The composites are doped into the photoanode of a solar cell. As anticipated, electrochemical impedance spectroscopy confirms the good electrical conductivity of the in situ synthesized rGO-UCNPs. Furthermore, the use of rGO-UCNPs in solar cells enables an enhancement in short-circuit current density and overall efficiency by about 10%. These findings reveal that the combination of UCNPs with rGO opens up new opportunities of extending the use of UCNPs in the area of solar energy harvesting.

  15. Uniform Cerium-Based Coordination Polymer Microsnheres: Preoaration and Upconversion Emission.

    PubMed

    Nie, Zhi-Wen; Zeng, Cheng-Hui; Xie, Gang; Zhong, Sheng-Liang

    2016-04-01

    Homogeneously doped Yb3+ and Er3+ cerium-based coordination polymer (CP) microspheres have been successfully synthesized on a large scale through a simple solvothermal route with 2,5-pyridinedicarboxylic acid (2,5-H2PDC) as the organic linker. CeO2: Yb3+, Er3+ porous microspheres were obtained by annealing the corresponding CP microspheres at 600 °C for 4 h under atmospheric pressure. These as-prepared products were characterized by Powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), energy-dispersion X-ray (EDX) spectroscopy, Thermogravimetric (TG) and derivative thermogravimetric (DTG) analysis. The room temperature upconversion luminescent spectra of the as-prepared microspheres were carried out by 980 nm NIR light excitation. Interestingly, Yb3+ and Er3+ codoped CP microspheres give a single-band emission centered at 673 nm, while the CeO2: Yb3+, Er3+ microspheres give emission in green and red region, with red being the dominant emission. The emission intensity of the CeO2: Yb3+, Er3+ microspheres were much stronger than that of the Yb3+ and Er3+ codoped CP microspheres. PMID:27451693

  16. All-fiber upconversion high spectral resolution wind lidar using a Fabry-Perot interferometer.

    PubMed

    Shangguan, Mingjia; Xia, Haiyun; Wang, Chong; Qiu, Jiawei; Shentu, Guoliang; Zhang, Qiang; Dou, Xiankang; Pan, Jian-Wei

    2016-08-22

    An all-fiber, micro-pulse and eye-safe high spectral resolution wind lidar (HSRWL) at 1.5 μm is proposed and demonstrated by using a pair of upconversion single-photon detectors and a fiber Fabry-Perot scanning interferometer (FFP-SI). In order to improve the optical detection efficiency, both the transmission spectrum and the reflection spectrum of the FFP-SI are used for spectral analyses of the aerosol backscatter and the reference laser pulse. Taking advantages of high signal-to-noise ratio of the detectors and high spectral resolution of the FFP-SI, the center frequencies and the bandwidths of spectra of the aerosol backscatter are obtained simultaneously. Continuous LOS wind observations are carried out on two days at Hefei (31.843 °N, 117.265 °E), China. The horizontal detection range of 4 km is realized with temporal resolution of 1 minute. The spatial resolution is switched from 30 m to 60 m at distance of 1.8 km. In a comparison experiment, LOS wind measurements from the HSRWL show good agreement with the results from an ultrasonic wind sensor (Vaisala windcap WMT52). An empirical method is adopted to evaluate the precision of the measurements. The standard deviation of the wind speed is 0.76 m/s at 1.8 km. The standard deviation of bandwidth variation is 2.07 MHz at 1.8 km. PMID:27557211

  17. Upconversion-induced delayed fluorescence in multicomponent organic systems: Role of Dexter energy transfer

    NASA Astrophysics Data System (ADS)

    Monguzzi, A.; Tubino, R.; Meinardi, F.

    2008-04-01

    The efficiency of the upconversion-induced delayed fluorescence in a solution of multicomponent organic systems is limited by two steps of the overall process: (i) a triplet-triplet energy transfer between a phosphorescent donor and an emitting acceptor, and (ii) a bimolecular acceptor triplet-triplet annihilation generating acceptor singlet excited states from which the high-energy emission takes place. In this work, the energy transfer process has been investigated in a model system constituted by solutions of Pt(II)octaethylporphyrin, which acts as a donor, and 9,10 diphenylanthracene, which acts as an acceptor. At low temperature, the experimental data have been interpreted in the frame of a pure Dexter energy transfer by using the Perrin approximation. A Dexter radius as large as 26.5 Å has been found. At room temperature, the fast diffusion of the molecules in the solution is no longer negligible, which gives rise to a strong increase in the energy transfer rates.

  18. Highly Efficient Photon Upconversion in Self-Assembled Light-Harvesting Molecular Systems

    PubMed Central

    Ogawa, Taku; Yanai, Nobuhiro; Monguzzi, Angelo; Kimizuka, Nobuo

    2015-01-01

    To meet the world’s demands on the development of sunlight-powered renewable energy production, triplet–triplet annihilation-based photon upconversion (TTA–UC) has raised great expectations. However, an ideal highly efficient, low-power, and in-air TTA–UC has not been achieved. Here, we report a novel self-assembly approach to achieve this, which enabled highly efficient TTA–UC even in the presence of oxygen. A newly developed lipophilic 9,10-diphenylanthracene-based emitter molecule functionalized with multiple hydrogen-bonding moieties spontaneously coassembled with a triplet sensitizer in organic media, showing efficient triplet sensitization and subsequent triplet energy migration among the preorganized chromophores. This supramolecular light-harvesting system shows a high UC quantum yield of 30% optimized at low excitation power in deaerated conditions. Significantly, the UC emission largely remains even in an air-saturated solution, and this approach is facilely applicable to organogel and solid-film systems. PMID:26057321

  19. Upconversion nanosensor for sensitive fluorescence detection of Sudan I-IV based on inner filter effect.

    PubMed

    Fang, Aijin; Long, Qian; Wu, Qiongqiong; Li, Haitao; Zhang, Youyu; Yao, Shouzhuo

    2016-01-01

    Sudan dyes are banned as food additives due to the carcinogenicity of their metabolites in the human body. Therefore, it is of great significance for sensitive detection of Sudan dyes. This paper reports a novel nanosensor for Sudan dyes detection based on fluorescence (FL) quenching of hexadecyl trimethyl ammonium bromide (CTAB) stabilized upconversion nanoparticles (UCNPs) through the inner filter effect (IFE). In the presence of Sudan I-IV, the fluorescence emission of UCNPs was effectively quenched due to the absorption bands of Sudan I-IV largely covered the emission bands of UCNPs. Under the optimized conditions, the FL was quenched with Sudan concentration over the range of 0.05-40, 0.01-20, 0.01-40 and 0.05-40 μg/mL for Sudan I-IV, respectively. The corresponding limit of detection is 15.1, 2.83, 3.52 and 16.7 ng/mL (at 3σ/slope) respectively. Meanwhile, the nanosensor shows good selectivity, sensitivity and can be successfully applied to detection of Sudan in chili powder samples.

  20. Mycobacterial phosphatidylinositol mannoside is a natural antigen for CD1d-restricted T cells

    PubMed Central

    Fischer, Karsten; Scotet, Emmanuel; Niemeyer, Marcus; Koebernick, Heidrun; Zerrahn, Jens; Maillet, Sophie; Hurwitz, Robert; Kursar, Mischo; Bonneville, Marc; Kaufmann, Stefan H. E.; Schaible, Ulrich E.

    2004-01-01

    A group of T cells recognizes glycolipids presented by molecules of the CD1 family. The CD1d-restricted natural killer T cells (NKT cells) are primarily considered to be self-reactive. By employing CD1d-binding and T cell assays, the following structural parameters for presentation by CD1d were defined for a number of mycobacterial and mammalian lipids: two acyl chains facilitated binding, and a polar head group was essential for T cell recognition. Of the mycobacterial lipids tested, only a phosphatidylinositol mannoside (PIM) fulfilled the requirements for CD1d binding and NKT cell stimulation. This PIM activated human and murine NKT cells via CD1d, thereby triggering antigen-specific IFN-γ production and cell-mediated cytotoxicity, and PIM-loaded CD1d tetramers identified a subpopulation of murine and human NKT cells. This phospholipid, therefore, represents a mycobacterial antigen recognized by T cells in the context of CD1d. PMID:15243159

  1. Structure and Catalytic Mechanism of Human Steroid 5-Reductase (AKR1D1)

    SciTech Connect

    Costanzo, L.; Drury, J; Christianson, D; Penning, T

    2009-01-01

    Human steroid 5{beta}-reductase (aldo-keto reductase (AKR) 1D1) catalyzes reduction of {Delta}{sup 4}-ene double bonds in steroid hormones and bile acid precursors. We have reported the structures of an AKR1D1-NADP{sup +} binary complex, and AKR1D1-NADP{sup +}-cortisone, AKR1D1-NADP{sup +}-progesterone and AKR1D1-NADP{sup +}-testosterone ternary complexes at high resolutions. Recently, structures of AKR1D1-NADP{sup +}-5{beta}-dihydroprogesterone complexes showed that the product is bound unproductively. Two quite different mechanisms of steroid double bond reduction have since been proposed. However, site-directed mutagenesis supports only one mechanism. In this mechanism, the 4-pro-R hydride is transferred from the re-face of the nicotinamide ring to C5 of the steroid substrate. E120, a unique substitution in the AKR catalytic tetrad, permits a deeper penetration of the steroid substrate into the active site to promote optimal reactant positioning. It participates with Y58 to create a 'superacidic' oxyanion hole for polarization of the C3 ketone. A role for K87 in the proton relay proposed using the AKR1D1-NADP{sup +}-5{beta}-dihydroprogesterone structure is not supported.

  2. TBC1D14 regulates autophagy via the TRAPP complex and ATG9 traffic.

    PubMed

    Lamb, Christopher A; Nühlen, Stefanie; Judith, Delphine; Frith, David; Snijders, Ambrosius P; Behrends, Christian; Tooze, Sharon A

    2016-02-01

    Macroautophagy requires membrane trafficking and remodelling to form the autophagosome and deliver its contents to lysosomes for degradation. We have previously identified the TBC domain-containing protein, TBC1D14, as a negative regulator of autophagy that controls delivery of membranes from RAB11-positive recycling endosomes to forming autophagosomes. In this study, we identify the TRAPP complex, a multi-subunit tethering complex and GEF for RAB1, as an interactor of TBC1D14. TBC1D14 binds to the TRAPP complex via an N-terminal 103 amino acid region, and overexpression of this region inhibits both autophagy and secretory traffic. TRAPPC8, the mammalian orthologue of a yeast autophagy-specific TRAPP subunit, forms part of a mammalian TRAPPIII-like complex and both this complex and TBC1D14 are needed for RAB1 activation. TRAPPC8 modulates autophagy and secretory trafficking and is required for TBC1D14 to bind TRAPPIII. Importantly, TBC1D14 and TRAPPIII regulate ATG9 trafficking independently of ULK1. We propose a model whereby TBC1D14 and TRAPPIII regulate a constitutive trafficking step from peripheral recycling endosomes to the early Golgi, maintaining the cycling pool of ATG9 required for initiation of autophagy. PMID:26711178

  3. Role and regulation of CD1d in normal and pathological B cells

    PubMed Central

    Chaudhry, Mohammed S.; Karadimitris, Anastasios

    2015-01-01

    CD1d is a non-polymorphic, MHC class I-like molecule, which presents phosphoand glycosphingo-lipid antigens to a subset of CD1d-restricted T cells called invariant NKT (iNKT) cells. This CD1d-iNKT cell axis regulates nearly all aspects of both the innate and adaptive immune response. Expression of CD1d on B cells is suggestive of the ability of these cells to present antigen to and form cognate interactions with iNKT cells. Herein we summarise key evidence regarding the role and regulation of CD1d in normal B cells and in humoral immunity. We then extend the discussion to B cell disorders, with emphasis on autoimmune disease, viral infection and neoplastic transformation of B lineage cells, where CD1d expression can be altered as a mechanism of immune evasion, and can have both diagnostic and prognostic importance. Finally we highlight current and future therapeutic strategies that aim to target the CD1d-iNKT axis in B cells. PMID:25381357

  4. Calreticulin Controls the Rate of Assembly of CD1d Molecules in the Endoplasmic Reticulum*

    PubMed Central

    Zhu, Yajuan; Zhang, Wei; Veerapen, Natacha; Besra, Gurdyal; Cresswell, Peter

    2010-01-01

    CD1d is an MHC class I-like molecule comprised of a transmembrane glycoprotein (heavy chain) associated with β2-microglobulin (β2m) that presents lipid antigens to NKT cells. Initial folding of the heavy chain involves its glycan-dependent association with calreticulin (CRT), calnexin (CNX), and the thiol oxidoreductase ERp57, and is followed by assembly with β2m to form the heterodimer. Here we show that in CRT-deficient cells CD1d heavy chains convert to β2m-associated dimers at an accelerated rate, indicating faster folding of the heavy chain, while the rate of intracellular transport after assembly is unaffected. Unlike the situation with MHC class I molecules, antigen presentation by CD1d is not impaired in the absence of CRT. Instead, there are elevated levels of stable and functional CD1d on the surface of CRT-deficient cells. Association of the heavy chains with the ER chaperones Grp94 and Bip is observed in the absence of CRT, and these may replace CRT in mediating CD1d folding and assembly. ER retention of free CD1d heavy chains is impaired in CRT-deficient cells, allowing their escape and subsequent expression on the plasma membrane. However, these free heavy chains are rapidly internalized and degraded in lysosomes, indicating that β2m association is required for the exceptional resistance of CD1d to lysosomal degradation that is normally observed. PMID:20861015

  5. The FC-1D: The profitable alternative Flying Circus Commercial Aviation Group

    NASA Technical Reports Server (NTRS)

    Meza, Victor J.; Alvarez, Jaime; Harrington, Brook; Lujan, Michael A.; Mitlyng, David; Saroughian, Andy; Silva, Alex; Teale, Tim

    1994-01-01

    The FC-1D was designed as an advanced solution for a low cost commercial transport meeting or exceeding all of the 1993/1994 AIAA/Lockheed request for proposal requirements. The driving philosophy behind the design of the FC-1D was the reduction of airline direct operating costs. Every effort was made during the design process to have the customer in mind. The Flying Circus Commercial Aviation Group targeted reductions in drag, fuel consumption, manufacturing costs, and maintenance costs. Flying Circus emphasized cost reduction throughout the entire design program. Drag reduction was achieved by implementation of the aft nacelle wing configuration to reduce cruise drag and increase cruise speeds. To reduce induced drag, rather than increasing the wing span of the FC-1D, spiroids were included in the efficient wing design. Profile and friction drag are reduced by using riblets in place of paint around the fuselage and empennage of the FC-1D. Choosing a single aisle configuration enabled the Flying Circus to optimize the fuselage diameter. Thus, reducing fuselage drag while gaining high structural efficiency. To further reduce fuel consumption a weight reduction program was conducted through the use of composite materials. An additional quality of the FC-1D is its design for low cost manufacturing and assembly. As a result of this design attribute, the FC-1D will have fewer parts which reduces weight as well as maintenance and assembly costs. The FC-1D is affordable and effective, the apex of commercial transport design.

  6. Efficient holmium-doped fluoride fiber laser emitting 2.1 µm and blue upconversion fluorescence upon excitation at 2 µm.

    PubMed

    Guhur, A; Jackson, S D

    2010-09-13

    We demonstrate a highly efficient and high power Ho(3+)-doped fluoride glass fiber laser that is resonantly pumped with a Tm(3+)-doped silicate glass fiber laser operating at 2.051 µm. The laser operates at 2080 nm and generated 6.66 W at a slope efficiency of 72%. We observe strong visible upconversion fluorescence centered at a variety of wavelengths including 491 nm which results from three sequential energy transfer upconversion processes; the fluorescence to pump energy ratio for this emission is one the largest reported to date. PMID:20940907

  7. Efficient holmium-doped fluoride fiber laser emitting 2.1 µm and blue upconversion fluorescence upon excitation at 2 µm.

    PubMed

    Guhur, A; Jackson, S D

    2010-09-13

    We demonstrate a highly efficient and high power Ho(3+)-doped fluoride glass fiber laser that is resonantly pumped with a Tm(3+)-doped silicate glass fiber laser operating at 2.051 µm. The laser operates at 2080 nm and generated 6.66 W at a slope efficiency of 72%. We observe strong visible upconversion fluorescence centered at a variety of wavelengths including 491 nm which results from three sequential energy transfer upconversion processes; the fluorescence to pump energy ratio for this emission is one the largest reported to date.

  8. Up-conversion luminescence in Er{sup 3+}/Yb{sup 3+}-codoped PbTiO{sub 3} perovskite obtained via Pechini method

    SciTech Connect

    Lemos, F.C.D.; Melo, D.M.A.; Silva, J.E.C. da . E-mail: jecs@uft.edu.br

    2005-01-04

    Efficient infrared-to-visible conversion by Er{sup 3+}/Yb{sup 3+}-codoped PbTiO{sub 3} perovskite will be reported. The process is observed under 980 nm laser diode (GAs:Si) excitation and results in the generation of green ({approx}555 nm) and red ({approx}655 nm) emission. The main mechanism that allows for up-conversion is attributed the energy transfer among Yb and Er ions in excited states. The power up-conversion efficiency for red emission is predominant in this material. The results illustrate the large potential of this new class of material for photonic applications involving optoelectronics devices.

  9. On the current drive capability of low dimensional semiconductors: 1D versus 2D

    DOE PAGES

    Zhu, Y.; Appenzeller, J.

    2015-10-29

    Low-dimensional electronic systems are at the heart of many scaling approaches currently pursuit for electronic applications. Here, we present a comparative study between an array of one-dimensional (1D) channels and its two-dimensional (2D) counterpart in terms of current drive capability. Lastly, our findings from analytical expressions derived in this article reveal that under certain conditions an array of 1D channels can outperform a 2D field-effect transistor because of the added degree of freedom to adjust the threshold voltage in an array of 1D devices.

  10. TCTEX1D2 mutations underlie Jeune asphyxiating thoracic dystrophy with impaired retrograde intraflagellar transport.

    PubMed

    Schmidts, Miriam; Hou, Yuqing; Cortés, Claudio R; Mans, Dorus A; Huber, Celine; Boldt, Karsten; Patel, Mitali; van Reeuwijk, Jeroen; Plaza, Jean-Marc; van Beersum, Sylvia E C; Yap, Zhi Min; Letteboer, Stef J F; Taylor, S Paige; Herridge, Warren; Johnson, Colin A; Scambler, Peter J; Ueffing, Marius; Kayserili, Hulya; Krakow, Deborah; King, Stephen M; Beales, Philip L; Al-Gazali, Lihadh; Wicking, Carol; Cormier-Daire, Valerie; Roepman, Ronald; Mitchison, Hannah M; Witman, George B

    2015-01-01

    The analysis of individuals with ciliary chondrodysplasias can shed light on sensitive mechanisms controlling ciliogenesis and cell signalling that are essential to embryonic development and survival. Here we identify TCTEX1D2 mutations causing Jeune asphyxiating thoracic dystrophy with partially penetrant inheritance. Loss of TCTEX1D2 impairs retrograde intraflagellar transport (IFT) in humans and the protist Chlamydomonas, accompanied by destabilization of the retrograde IFT dynein motor. We thus define TCTEX1D2 as an integral component of the evolutionarily conserved retrograde IFT machinery. In complex with several IFT dynein light chains, it is required for correct vertebrate skeletal formation but may be functionally redundant under certain conditions. PMID:26044572

  11. TCTEX1D2 mutations underlie Jeune asphyxiating thoracic dystrophy with impaired retrograde intraflagellar transport

    PubMed Central

    Schmidts, Miriam; Hou, Yuqing; Cortés, Claudio R.; Mans, Dorus A.; Huber, Celine; Boldt, Karsten; Patel, Mitali; van Reeuwijk, Jeroen; Plaza, Jean-Marc; van Beersum, Sylvia E. C.; Yap, Zhi Min; Letteboer, Stef J. F.; Taylor, S. Paige; Herridge, Warren; Johnson, Colin A.; Scambler, Peter J.; Ueffing, Marius; Kayserili, Hulya; Krakow, Deborah; King, Stephen M.; Beales, Philip L.; Al-Gazali, Lihadh; Wicking, Carol; Cormier-Daire, Valerie; Roepman, Ronald; Mitchison, Hannah M.; Witman, George B.; Al-Turki, Saeed; Anderson, Carl; Anney, Richard; Antony, Dinu; Asimit, Jennifer; Ayub, Mohammad; Barrett, Jeff; Barroso, Inês; Bentham, Jamie; Bhattacharya, Shoumo; Blackwood, Douglas; Bobrow, Martin; Bochukova, Elena; Bolton, Patrick; Boustred, Chris; Breen, Gerome; Brion, Marie-Jo; Brown, Andrew; Calissano, Mattia; Carss, Keren; Chatterjee, Krishna; Chen, Lu; Cirak, Sebhattin; Clapham, Peter; Clement, Gail; Coates, Guy; Collier, David; Cosgrove, Catherine; Cox, Tony; Craddock, Nick; Crooks, Lucy; Curran, Sarah; Daly, Allan; Danecek, Petr; Smith, George Davey; Day-Williams, Aaron; Day, Ian; Durbin, Richard; Edkins, Sarah; Ellis, Peter; Evans, David; Farooqi, I. Sadaf; Fatemifar, Ghazaleh; Fitzpatrick, David; Flicek, Paul; Floyd, Jamie; Foley, A. Reghan; Franklin, Chris; Futema, Marta; Gallagher, Louise; Gaunt, Tom; Geschwind, Daniel; Greenwood, Celia; Grozeva, Detelina; Guo, Xiaosen; Gurling, Hugh; Hart, Deborah; Hendricks, Audrey; Holmans, Peter; Huang, Jie; Humphries, Steve E.; Hurles, Matt; Hysi, Pirro; Jackson, David; Jamshidi, Yalda; Jewell, David; Chris, Joyce; Kaye, Jane; Keane, Thomas; Kemp, John; Kennedy, Karen; Kent, Alastair; Kolb-Kokocinski, Anja; Lachance, Genevieve; Langford, Cordelia; Lee, Irene; Li, Rui; Li, Yingrui; Ryan, Liu; Lönnqvist, Jouko; Lopes, Margarida; MacArthur, Daniel G.; Massimo, Mangino; Marchini, Jonathan; Maslen, John; McCarthy, Shane; McGuffin, Peter; McIntosh, Andrew; McKechanie, Andrew; McQuillin, Andrew; Memari, Yasin; Metrustry, Sarah; Min, Josine; Moayyeri, Alireza; Morris, James; Muddyman, Dawn; Muntoni, Francesco; Northstone, Kate; O'Donovan, Michael; O'Rahilly, Stephen; Onoufriadis, Alexandros; Oualkacha, Karim; Owen, Michael; Palotie, Aarno; Panoutsopoulou, Kalliope; Parker, Victoria; Parr, Jeremy; Paternoster, Lavinia; Paunio, Tiina; Payne, Felicity; Perry, John; Pietilainen, Olli; Plagnol, Vincent; Quail, Michael A.; Quaye, Lydia; Raymond, Lucy; Rehnström, Karola; Brent Richards, J.; Ring, Sue; Ritchie, Graham R S; Savage, David B.; Schoenmakers, Nadia; Semple, Robert K.; Serra, Eva; Shihab, Hashem; Shin, So-Youn; Skuse, David; Small, Kerrin; Smee, Carol; Soler, Artigas María; Soranzo, Nicole; Southam, Lorraine; Spector, Tim; St Pourcain, Beate; St. Clair, David; Stalker, Jim; Surdulescu, Gabriela; Suvisaari, Jaana; Tachmazidou, Ioanna; Tian, Jing; Timpson, Nic; Tobin, Martin; Valdes, Ana; van Kogelenberg, Margriet; Vijayarangakannan, Parthiban; Wain, Louise; Walter, Klaudia; Wang, Jun; Ward, Kirsten; Wheeler, Ellie; Whittall, Ros; Williams, Hywel; Williamson, Kathy; Wilson, Scott G.; Wong, Kim; Whyte, Tamieka; ChangJiang, Xu; Zeggini, Eleftheria; Zhang, Feng; Zheng, Hou-Feng

    2015-01-01

    The analysis of individuals with ciliary chondrodysplasias can shed light on sensitive mechanisms controlling ciliogenesis and cell signalling that are essential to embryonic development and survival. Here we identify TCTEX1D2 mutations causing Jeune asphyxiating thoracic dystrophy with partially penetrant inheritance. Loss of TCTEX1D2 impairs retrograde intraflagellar transport (IFT) in humans and the protist Chlamydomonas, accompanied by destabilization of the retrograde IFT dynein motor. We thus define TCTEX1D2 as an integral component of the evolutionarily conserved retrograde IFT machinery. In complex with several IFT dynein light chains, it is required for correct vertebrate skeletal formation but may be functionally redundant under certain conditions. PMID:26044572

  12. Comet Halley O(1D) and H2O production rates

    NASA Technical Reports Server (NTRS)

    Magee-Sauer, K.; Scherb, F.; Roesler, F. L.; Harlander, J.

    1990-01-01

    Ground-based dual-etalon Fabry-Perot spectrometer observations have been made of Comet Halley's forbidden O I 6300 A emission. The 0.2 A resolution of the spectral scans was sufficient to resolve the O I forbidden line emissions from both nearby cometary NH2 and telluric emissions. On the basis of these measurements, the production rate Q of O(1D) was determined; it is then found, by taking into account the photodissociation of H2O and OH as sources of O(1D), that the ratio of H2O/O(1D) production rates is of the order of 6.

  13. On the Current Drive Capability of Low Dimensional Semiconductors: 1D versus 2D.

    PubMed

    Zhu, Y; Appenzeller, J

    2015-12-01

    Low-dimensional electronic systems are at the heart of many scaling approaches currently pursuit for electronic applications. Here, we present a comparative study between an array of one-dimensional (1D) channels and its two-dimensional (2D) counterpart in terms of current drive capability. Our findings from analytical expressions derived in this article reveal that under certain conditions an array of 1D channels can outperform a 2D field-effect transistor because of the added degree of freedom to adjust the threshold voltage in an array of 1D devices.

  14. Three-dimensional quick response code based on inkjet printing of upconversion fluorescent nanoparticles for drug anti-counterfeiting

    NASA Astrophysics Data System (ADS)

    You, Minli; Lin, Min; Wang, Shurui; Wang, Xuemin; Zhang, Ge; Hong, Yuan; Dong, Yuqing; Jin, Guorui; Xu, Feng

    2016-05-01

    Medicine counterfeiting is a serious issue worldwide, involving potentially devastating health repercussions. Advanced anti-counterfeit technology for drugs has therefore aroused intensive interest. However, existing anti-counterfeit technologies are associated with drawbacks such as the high cost, complex fabrication process, sophisticated operation and incapability in authenticating drug ingredients. In this contribution, we developed a smart phone recognition based upconversion fluorescent three-dimensional (3D) quick response (QR) code for tracking and anti-counterfeiting of drugs. We firstly formulated three colored inks incorporating upconversion nanoparticles with RGB (i.e., red, green and blue) emission colors. Using a modified inkjet printer, we printed a series of colors by precisely regulating the overlap of these three inks. Meanwhile, we developed a multilayer printing and splitting technology, which significantly increases the information storage capacity per unit area. As an example, we directly printed the upconversion fluorescent 3D QR code on the surface of drug capsules. The 3D QR code consisted of three different color layers with each layer encoded by information of different aspects of the drug. A smart phone APP was designed to decode the multicolor 3D QR code, providing the authenticity and related information of drugs. The developed technology possesses merits in terms of low cost, ease of operation, high throughput and high information capacity, thus holds great potential for drug anti-counterfeiting.Medicine counterfeiting is a serious issue worldwide, involving potentially devastating health repercussions. Advanced anti-counterfeit technology for drugs has therefore aroused intensive interest. However, existing anti-counterfeit technologies are associated with drawbacks such as the high cost, complex fabrication process, sophisticated operation and incapability in authenticating drug ingredients. In this contribution, we developed a

  15. Up-conversion luminescence of the NaYF4:Yb3+,Er3+ nanomaterials prepared with the solvothermal synthesis

    NASA Astrophysics Data System (ADS)

    Palo, Emilia; Pihlgren, Laura; Tuomisto, Minnea; Laihinen, Tero; Hyppänen, Iko; Kankare, Jouko; Lastusaari, Mika; Soukka, Tero; Swart, Hendrik C.; Hölsä, Jorma

    2016-09-01

    Up-converting NaYF4:Yb3+,Er3+ (xYb: 0.20, xEr: 0.02) nanomaterials were prepared with a microwave assisted solvothermal synthesis to study how the synthesis parameters affect the structure and up-conversion luminescence of the materials and thus their usability as labels in biomedical applications. The purity of the materials was studied with Fourier transform infra-red (FT-IR) spectroscopy and the particle size and morphology with transmission electron microscopy (TEM). The crystal structure was characterized with X-ray powder diffraction (XPD) and the crystallite sizes were calculated with the Scherrer formula. Up-conversion luminescence and luminescence decays were studied with near infra-red (NIR) laser excitation at 970 nm. The presence of the oleic acid was observed in the FT-IR spectra. The TEM images showed small quasi-spherical nanoparticles as well as long nanorods. The XPD measurements revealed that both cubic and hexagonal forms of NaYF4 were present in the materials. The crystallite sizes ranged from ca. 20 to over 150 nm for the cubic and hexagonal phases, respectively. The characteristic up-conversion luminescence of Er3+ in red (640-685 nm; 4F9/2 → 4I15/2) and green (515-560 nm; 2H11/2, 4S3/2 → 4I15/2 transitions) wavelengths was observed. The most intense luminescence and the longest luminescence emission lifetime were obtained with the material annealed for 12 h at 177 °C with 1.8 MPa pressure due to the predominance of the well-crystallized hexagonal form of NaRF4 (R: Y, Yb, Er).

  16. Facile synthesis of 5 nm NaYF₄:Yb/Er nanoparticles for targeted upconversion imaging of cancer cells.

    PubMed

    Hu, Yueli; Wu, Boyue; Jin, Qing; Wang, Xueyuan; Li, Yan; Sun, Yuxiu; Huo, Jianzhong; Zhao, Xiaojun

    2016-05-15

    5nm intense green emission NaYF4:Yb/Er upconversion nanoparticles (UCNPs) with pure β phase was synthesized with a simple "green" strategy for the first time. Traditional organic solvothermal method is often applied to prepare the high-quality and uniform UCNPs, but the preparation of lanthanide-oleate complexes is laborious as heating and multistep post-treatment for purification are often required. The water-alcohols solvothermal method is environmentally friendly, but the fabricated UCNPs have big size, poor biocompatibility and high cytotoxicity, which limited their application for cell imaging. Herein, NaYF4:Yb/Er UCNPs were prepared with rare-earth nitrates RE(NO3)3 (RE=Y0.80 Yb0.18 Er0.02) as precursors and diethylene glycol (DEG)/ethylene glycol (EG)/water as the solvent. A facile green solvothermal method with the temperature being controlled at 300°C was developed. The as-prepared NaYF4:Yb/Er UCNPs were characterized and were found to have enhanced UC emission and controllable particle size. The as-prepared UCNPs were further functionalized via folic acid coating for the targeted imaging and improved bio- compatibility. It was made the UCNPs potential for upconversion bioimaging of living cells by the strong upconversion luminescence, the excellent biocompatibility, and the super-small size. The good colloidal stability and low cell cytotoxicity of the as-prepared UCNPs and the developed synthesis protocol might advance both the fields of UCNPs and biomolecule-based nanotechnology for future studies. PMID:26992548

  17. Comprehensive study on different crystal field environments in highly efficient NaLaF4:Er3+ upconversion phosphor

    NASA Astrophysics Data System (ADS)

    Sarakovskis, Anatolijs; Krieke, Guna; Doke, Guna; Grube, Jurgis; Grinberga, Liga; Springis, Maris

    2015-01-01

    Complex fluorides, especially rare-earth doped NaREF4 (RE = Y3+, La3+ or Gd3+), are promising materials for the upconversion luminescence mostly due to low phonon energy of their matrices and multisite nature of the crystalline lattice. Although multisite formation in hexagonal NaREF4 structures has generally been proved, the actual number of the active sites in different structures varies from two (NaGdF4) to seven (NaYF4). The aim of this work has been to study multisite formation in NaLaF4:Er3+. For this purpose low-temperature site-selective spectroscopy measurements in hexagonal NaLaF4:Er3+ have been performed. Excitation at different wavelengths corresponding to the excitation of 4F7/2 level of Er3+ ions has revealed three distinct luminescence spectra in the green spectral region associated with 4S3/2 → 4I15/2 electronic transition. The number of the spectra has been sufficient to model experimentally measured luminescence spectra at any excitation wavelength as a linear combination of the distinct spectra. The analysis of the structure of the material and the results of site-selective spectroscopy signify the presence of at least three different crystalline field environments where Er3+ ions incorporate. Upon site-selective excitation of Er3+ located at a specific site energy transfer to erbium ions located at other sites has been observed in both the upconversion and downconversion luminescence processes. The enhanced energy transfer between the different sites in NaLaF4:Er3+ signifies the importance of the multisite nature of the structure, which is a key factor for an efficient upconversion luminescence.

  18. Ubiquitination and degradation of the hominoid-specific oncoprotein TBC1D3 is regulated by protein palmitoylation

    SciTech Connect

    Kong, Chen; Lange, Jeffrey J.; Samovski, Dmitri; Su, Xiong; Liu, Jialiu; Sundaresan, Sinju; Stahl, Philip D.

    2013-05-03

    Highlights: •Hominoid-specific oncogene TBC1D3 is targeted to plasma membrane by palmitoylation. •TBC1D3 is palmitoylated on two cysteine residues: 318 and 325. •TBC1D3 palmitoylation governs growth factors-induced TBC1D3 degradation. •Post-translational modifications may regulate oncogenic properties of TBC1D3. -- Abstract: Expression of the hominoid-specific oncoprotein TBC1D3 promotes enhanced cell growth and proliferation by increased activation of signal transduction through several growth factors. Recently we documented the role of CUL7 E3 ligase in growth factors-induced ubiquitination and degradation of TBC1D3. Here we expanded our study to discover additional molecular mechanisms that control TBC1D3 protein turnover. We report that TBC1D3 is palmitoylated on two cysteine residues: 318 and 325. The expression of double palmitoylation mutant TBC1D3:C318/325S resulted in protein mislocalization and enhanced growth factors-induced TBC1D3 degradation. Moreover, ubiquitination of TBC1D3 via CUL7 E3 ligase complex was increased by mutating the palmitoylation sites, suggesting that depalmitoylation of TBC1D3 makes the protein more available for ubiquitination and degradation. The results reported here provide novel insights into the molecular mechanisms that govern TBC1D3 protein degradation. Dysregulation of these mechanisms in vivo could potentially result in aberrant TBC1D3 expression and promote oncogenesis.

  19. Near-infrared light triggered photodynamic therapy in combination with gene therapy using upconversion nanoparticles for effective cancer cell killing

    NASA Astrophysics Data System (ADS)

    Wang, Xin; Liu, Kai; Yang, Guangbao; Cheng, Liang; He, Lu; Liu, Yumeng; Li, Yonggang; Guo, Liang; Liu, Zhuang

    2014-07-01

    Upconversion nanoparticles (UCNPs) have drawn much attention in cancer imaging and therapy in recent years. Herein, we for the first time report the use of UCNPs with carefully engineered surface chemistry for combined photodynamic therapy (PDT) and gene therapy of cancer. In our system, positively charged NaGdF4:Yb,Er UCNPs with multilayered polymer coatings are synthesized via a layer by layer strategy, and then loaded simultaneously with Chlorin e6 (Ce6), a photosensitizing molecule, and small interfering RNA (siRNA), which targets the Plk1 oncogene. On the one hand, under excitation by a near-infrared (NIR) light at 980 nm, which shows greatly improved tissue penetration compared with visible light, cytotoxic singlet oxygen can be generated via resonance energy transfer from UCNPs to photosensitizer Ce6, while the residual upconversion luminescence is utilized for imaging. On the other hand, the silencing of Plk1 induced by siRNA delivered with UCNPs could induce significant cancer cell apoptosis. As the result of such combined photodynamic and gene therapy, a remarkably enhanced cancer cell killing effect is realized. Our work thus highlights the promise of UCNPs for imaging guided combination therapy of cancer.Upconversion nanoparticles (UCNPs) have drawn much attention in cancer imaging and therapy in recent years. Herein, we for the first time report the use of UCNPs with carefully engineered surface chemistry for combined photodynamic therapy (PDT) and gene therapy of cancer. In our system, positively charged NaGdF4:Yb,Er UCNPs with multilayered polymer coatings are synthesized via a layer by layer strategy, and then loaded simultaneously with Chlorin e6 (Ce6), a photosensitizing molecule, and small interfering RNA (siRNA), which targets the Plk1 oncogene. On the one hand, under excitation by a near-infrared (NIR) light at 980 nm, which shows greatly improved tissue penetration compared with visible light, cytotoxic singlet oxygen can be generated via

  20. Polarimetric passive millimeter-wave imagery from a sensor based on an optical up-conversion architecture

    NASA Astrophysics Data System (ADS)

    Wilson, John P.; Schuetz, Christopher A.; Dillon, Thomas E.; Martin, Richard D.; Prather, Dennis W.

    2012-06-01

    A passive millimeter-wave sensor based on optical up-conversion that is sensitive to the polarization state of incident radiation is described. This system up-converts incident millimeter-wave radiation to an optical frequency and then recreates the polarization state of the millimeter-wave radiation in the optical signal. A division of time approach is then used to extract the Stokes information from the signal using optical techniques. Results are shown which verify the feasibility of this approach and demonstrate the ability to control the phase of the signal to enable the measurement of Stokes information.