Sample records for strong alkaline microcavities

  1. Strong Exciton-photon Coupling in Semiconductor Microcavities

    DEFF Research Database (Denmark)

    Jensen, Jacob Riis; Borri, Paola; Hvam, Jørn Märcher


    The basic building block of vertical cavity surface emitting lasers (VCSELs) and high efficiency diodes, is a quantum well embedded in a semiconductor microcavity. The high finesse that may be achieved in such a cavity is utilised to get a low threshold current in the VCSELs and a high directiona......The basic building block of vertical cavity surface emitting lasers (VCSELs) and high efficiency diodes, is a quantum well embedded in a semiconductor microcavity. The high finesse that may be achieved in such a cavity is utilised to get a low threshold current in the VCSELs and a high......-optical switches based on semiconductor microcavities....

  2. Strong exciton-photon coupling in organic single crystal microcavity with high molecular orientation

    Energy Technology Data Exchange (ETDEWEB)

    Goto, Kaname [Department of Electronics, Graduate School of Science and Technology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585 (Japan); Yamashita, Kenichi, E-mail: [Faculty of Electrical Engineering and Electronics, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585 (Japan); Yanagi, Hisao [Graduate School of Materials Science, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama, Ikoma, Nara 630-0192 (Japan); Yamao, Takeshi; Hotta, Shu [Faculty of Materials Science and Technology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585 (Japan)


    Strong exciton-photon coupling has been observed in a highly oriented organic single crystal microcavity. This microcavity consists of a thiophene/phenylene co-oligomer (TPCO) single crystal laminated on a high-reflection distributed Bragg reflector. In the TPCO crystal, molecular transition dipole was strongly polarized along a certain horizontal directions with respect to the main crystal plane. This dipole polarization causes significantly large anisotropies in the exciton transition and optical constants. Especially the anisotropic exciton transition was found to provide the strong enhancement in the coupling with the cavity mode, which was demonstrated by a Rabi splitting energy as large as ∼100 meV even in the “half-vertical cavity surface emitting lasing” microcavity structure.

  3. Strong coupling and polariton lasing in Te based microcavities embedding (Cd,Zn)Te quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Rousset, J.-G., E-mail:; Piętka, B.; Król, M.; Mirek, R.; Lekenta, K.; Szczytko, J.; Borysiuk, J.; Suffczyński, J.; Kazimierczuk, T.; Goryca, M.; Smoleński, T.; Kossacki, P.; Nawrocki, M.; Pacuski, W. [Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, PL-02-093 Warszawa (Poland)


    We report on properties of an optical microcavity based on (Cd,Zn,Mg)Te layers and embedding (Cd,Zn)Te quantum wells. The key point of the structure design is the lattice matching of the whole structure to MgTe, which eliminates the internal strain and allows one to embed an arbitrary number of unstrained quantum wells in the microcavity. We evidence the strong light-matter coupling regime already for the structure containing a single quantum well. Embedding four unstrained quantum wells results in further enhancement of the exciton-photon coupling and the polariton lasing in the strong coupling regime.

  4. Strong coupling and stimulated emission in single parabolic quantum well microcavity for terahertz cascade

    International Nuclear Information System (INIS)

    Tzimis, A.; Savvidis, P. G.; Trifonov, A. V.; Ignatiev, I. V.; Christmann, G.; Tsintzos, S. I.; Hatzopoulos, Z.; Kavokin, A. V.


    We report observation of strong light-matter coupling in an AlGaAs microcavity (MC) with an embedded single parabolic quantum well. The parabolic potential is achieved by varying aluminum concentration along the growth direction providing equally spaced energy levels, as confirmed by Brewster angle reflectivity from a reference sample without MC. It acts as an active region of the structure which potentially allows cascaded emission of terahertz (THz) light. Spectrally and time resolved pump-probe spectroscopy reveals characteristic quantum beats whose frequencies range from 0.9 to 4.5 THz, corresponding to energy separation between relevant excitonic levels. The structure exhibits strong stimulated nonlinear emission with simultaneous transition to weak coupling regime. The present study highlights the potential of such devices for creating cascaded relaxation of bosons, which could be utilized for THz emission

  5. Room temperature strong coupling effects from single ZnO nanowire microcavity

    KAUST Repository

    Das, Ayan


    Strong coupling effects in a dielectric microcavity with a single ZnO nanowire embedded in it have been investigated at room temperature. A large Rabi splitting of ?100 meV is obtained from the polariton dispersion and a non-linearity in the polariton emission characteristics is observed at room temperature with a low threshold of 1.63 ?J/cm2, which corresponds to a polariton density an order of magnitude smaller than that for the Mott transition. The momentum distribution of the lower polaritons shows evidence of dynamic condensation and the absence of a relaxation bottleneck. The polariton relaxation dynamics were investigated by timeresolved measurements, which showed a progressive decrease in the polariton relaxation time with increase in polariton density. © 2012 Optical Society of America.

  6. Strong coupling between 0D and 2D modes in optical open microcavities (United States)

    Trichet, A. A. P.; Dolan, P. R.; Smith, J. M.


    We present a study of the coupling between confined modes and continuum states in an open microcavity system. The confined states are the optical modes of a plano-concave Fabry–Pérot cavity while the continuum states are the propagating modes in a surrounding planar cavity. The length tunability of the open cavity system allows to study the evolution of localised modes as they are progressively deconfined and coupled to the propagating modes. We observe an anti-crossing between the confined and propagating modes proving that mode-mixing takes place in between these two families of modes, and identify 0D–2D mixed modes which exhibit reduced loss compared with their highly localised counterparts. For practical design, we investigate the details of the microcavity shape that can be used to engineer the degree of mode-mixing. This study discusses for the first time experimentally and theoretically how light confinement arises in planar micromirrors and is of interest for the realisation of chip-based extended microphotonics using open cavities.

  7. A study of the cavity polariton under strong excitation:dynamics and nonlinearities in II-VI micro-cavities

    International Nuclear Information System (INIS)

    Muller, Markus


    This work contains an experimental study of the photoluminescence dynamics of cavity polaritons in strong coupling micro-cavities based on II-VI semiconductor compounds. The small exciton size and the strong exciton binding energy in these materials allowed us to study the strong coupling regime between photon and exciton up to high excitation densities, exploring the linear and non-linear emission regimes. Our main experimental techniques are picosecond time-resolved and angular photoluminescence spectroscopy. In the linear regime and for a negative photon-exciton detuning, we observe a suppression of the polariton relaxation by the emission of acoustic phonons leading to a non-equilibrium polariton distribution on the lower branch. This 'bottleneck' effect, which has already been described for polaritons in bulk semiconductors, results from the pronounced photon like character of the polaritons near k(parallel) = 0 in this configuration. At high excitation densities, non-linear relaxation processes, namely final state stimulation of the relaxation and polariton-polariton scattering, bypass this bottleneck giving rise to a very rapid relaxation down to the bottom of the band. We show that this dramatic change in the relaxation dynamics is finally responsible of the super-linear increase of the polariton emission from these states. (author) [fr

  8. Exciton Hybridisation in Organic-Inorganic Semiconductor Microcavities

    National Research Council Canada - National Science Library

    Lidzey, David


    ... that could be either a laser or a very efficient LED. The report describes fabrication of new types of microcavity containing organic semiconductors, including strongly-coupled microcavities based on two metallic mirrors...

  9. Carbon nanotube biconvex microcavities

    Energy Technology Data Exchange (ETDEWEB)

    Butt, Haider, E-mail:; Ahmed, Rajib [Nanotechnology Laboratory, School of Mechanical Engineering, University of Birmingham, Birmingham B15 2TT (United Kingdom); Yetisen, Ali K.; Yun, Seok Hyun [Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, 50 Blossom Street, Boston, Massachusetts 02114 (United States); Dai, Qing [National Center for Nanoscience and Technology, Beijing 100190 (China)


    Developing highly efficient microcavities with predictive narrow-band resonance frequencies using the least amount of material will allow the applications in nonlinear photonic devices. We have developed a microcavity array that comprised multi-walled carbon nanotubes (MWCNT) organized in a biconvex pattern. The finite element model allowed designing microcavity arrays with predictive transmission properties and assessing the effects of the microarray geometry. The microcavity array demonstrated negative index and produced high Q factors. 2–3 μm tall MWCNTs were patterned as biconvex microcavities, which were separated by 10 μm in an array. The microcavity was iridescent and had optical control over the diffracted elliptical patterns with a far-field pattern, whose properties were predicted by the model. It is anticipated that the MWCNT biconvex microcavities will have implications for the development of highly efficient lenses, metamaterial antennas, and photonic circuits.

  10. Biexcitons in semiconductor microcavities

    DEFF Research Database (Denmark)

    Borri, P.; Langbein, W.; Woggon, U.


    In this paper, the present status of the experimental study of the optical properties of biexcitons in semiconductor microcavities is reviewed. In particular, a detailed investigation of a polariton-biexciton transition in a high-quality single quantum well GaAs/AlGaAs microcavity is reported...

  11. Electromagnetically induced transparency in optical microcavities

    Directory of Open Access Journals (Sweden)

    Liu Yong-Chun


    Full Text Available Electromagnetically induced transparency (EIT is a quantum interference effect arising from different transition pathways of optical fields. Within the transparency window, both absorption and dispersion properties strongly change, which results in extensive applications such as slow light and optical storage. Due to the ultrahigh quality factors, massive production on a chip and convenient all-optical control, optical microcavities provide an ideal platform for realizing EIT. Here we review the principle and recent development of EIT in optical microcavities. We focus on the following three situations. First, for a coupled-cavity system, all-optical EIT appears when the optical modes in different cavities couple to each other. Second, in a single microcavity, all-optical EIT is created when interference happens between two optical modes. Moreover, the mechanical oscillation of the microcavity leads to optomechanically induced transparency. Then the applications of EIT effect in microcavity systems are discussed, including light delay and storage, sensing, and field enhancement. A summary is then given in the final part of the paper.

  12. Single Nanoparticle Detection Using Optical Microcavities. (United States)

    Zhi, Yanyan; Yu, Xiao-Chong; Gong, Qihuang; Yang, Lan; Xiao, Yun-Feng


    Detection of nanoscale objects is highly desirable in various fields such as early-stage disease diagnosis, environmental monitoring and homeland security. Optical microcavity sensors are renowned for ultrahigh sensitivities due to strongly enhanced light-matter interaction. This review focuses on single nanoparticle detection using optical whispering gallery microcavities and photonic crystal microcavities, both of which have been developing rapidly over the past few years. The reactive and dissipative sensing methods, characterized by light-analyte interactions, are explained explicitly. The sensitivity and the detection limit are essentially determined by the cavity properties, and are limited by the various noise sources in the measurements. On the one hand, recent advances include significant sensitivity enhancement using techniques to construct novel microcavity structures with reduced mode volumes, to localize the mode field, or to introduce optical gain. On the other hand, researchers attempt to lower the detection limit by improving the spectral resolution, which can be implemented by suppressing the experimental noises. We also review the methods of achieving a better temporal resolution by employing mode locking techniques or cavity ring up spectroscopy. In conclusion, outlooks on the possible ways to implement microcavity-based sensing devices and potential applications are provided. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Micelle formation during extraction of alkali elements from strongly alkaline mediums

    International Nuclear Information System (INIS)

    Apanasenko, V.V.; Reznik, A.M.; Bukin, V.I.; Brodskaya, A.V.


    Extraction of potassium, rubidium and cesium by phenol reagents in hydrocarbon solvents from strongly alkakine solutions was considered. Tendency of prepared alkali metal phenolates to form micelles in aqueous and organic phases was revealed. Phenolates tendency to form micelles is dictated mainly by the size and position of hydrocarbon substituent in molecule. It is shown that when micelles form in organic phase, alkali elements can be extracted both according to cation-exchange mechanism and according to micellar one. It is noted that alkai element extraction from strongly alkaline media requires the correct choice of extractant: alkali metal phenolate shouldn't form micelles in aqueous solution. n-Alkyl- and arylphenoldisulfides and polysulfides are most preferable for solvent extraction among considered phenol derivatives

  14. Stimulated secondary emission from semiconductor microcavities

    DEFF Research Database (Denmark)

    Østergaard, John Erland; Mizeikis, V.; Langbein, Wolfgang Werner


    We find strong influence of final-state stimulation on the time-resolved light emission dynamics from semiconductor microcavities after pulsed excitation allowing angle-resonant polariton-polariton scattering on the lower-polariton branch. The polariton dynamics can be controlled by injection...

  15. Quantum Logic Using Excitonic Quantum Dots in External Optical Microcavities

    National Research Council Canada - National Science Library

    Raymer, Michael


    An experimental project was undertaken to develop means to achieve quantum optical strong coupling between a single GaAs quantum dot and the optical mode of a microcavity for the purpose of quantum...

  16. Biexcitons in semiconductor microcavities

    DEFF Research Database (Denmark)

    Borri, P.; Langbein, W.; Woggon, U.


    in the microcavity, even if the vacuum Rabi splitting exceeds the biexciton binding energy. However, the presence of a longitudinal built-in electric field that results in a Stark effect slightly reducing the binding energy compared to the value measured on a reference bare quantum well is experimentally pointed out...

  17. Strong optical-mechanical coupling in a vertical GaAs/AlAs microcavity for subterahertz phonons and near-infrared light. (United States)

    Fainstein, A; Lanzillotti-Kimura, N D; Jusserand, B; Perrin, B


    We show that distributed Bragg reflector GaAs/AlAs vertical cavities designed to confine photons are automatically optimal to confine phonons of the same wavelength, strongly enhancing their interaction. We study the impulsive generation of intense coherent and monochromatic acoustic phonons by following the time evolution of the elastic strain in picosecond-laser experiments. Efficient optical detection is assured by the strong phonon backaction on the high-Q optical cavity mode. Large optomechanical factors are reported (~THz/nm range). Pillar cavities based in these structures are predicted to display picogram effective masses, almost perfect sound extraction, and threshold powers for the stimulated emission of phonons in the range μW-mW, opening the way for the demonstration of phonon "lasing" by parametric instability in these devices.

  18. Wavelength tuning of porous silicon microcavities

    International Nuclear Information System (INIS)

    Mulders, J.; Reece, P.; Zheng, W.H.; Lerondel, G.; Sun, B.; Gal, M.


    Full text: In the last decade much attention has been given to porous silicon (PS) for optoelectronic applications, which include efficient room temperature light emission as well as microcavity formation. Due to the large specific surface area, the use of porous silicon microcavities (PSMs) has been proposed for chemical sensing. Large wavelength shifts have indicated that the optical properties of PSMs are indeed strongly dependent on the environment. In this paper, we report the shifting of the resonance frequency of high quality PSMs, with the aim of tuning a future PS device to a certain required wavelength. The PSM samples were prepared by anodically etching p + -doped (5mΩcm) bulk silicon wafer in a solution (25%) of aqueous HF and ethanol. The device structure consisted of a PS layer sandwiched between 2 stacks of thin PS layers with alternating high and low effective refractive indices (RI), i.e. distributed Bragg mirrors (DBM). The layer thickness depends on the etch time while the porosity and hence refractive index is determined by the current density as the Si is etched. The position and the width of the stop-band can be fully controlled by the design of the DBMs, with the microcavity resonance mode sitting within the stop-band. We achieved tuning of the microcavity resonance by a number of methods, including temperature dependent tuning. The temperature induced wavelength shift was found to be of the order of 10 -15 nm. Computer modeling of these changes in the reflectivity spectra allowed us to quantify the changes of the effective refractive index and the respective layer thicknesses

  19. Quantum correlations in semiconductor microcavities (United States)

    Kira, M.; Hoyer, W.; Koch, S. W.; Brick, P.; Ell, C.; Hübner, M.; Khitrova, G.; Gibbs, H. M.


    The quantum mechanical nature of the light field in semiconductor microcavities leads to non-classical coupling effects between photons and electron-hole excitations. It is shown that these quantum correlations give rise to characteristic corrections of the semiclassical light-matter coupling dynamics. Examples of quantum correlation signatures include entanglement effects in the probe reflection of a microcavity system and squeezing in the incoherent emission.

  20. Multiwall carbon nanotube microcavity arrays

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Rajib; Butt, Haider, E-mail: [Nanotechnology Laboratory, School of Mechanical Engineering, University of Birmingham, Birmingham B15 2TT (United Kingdom); Rifat, Ahmmed A. [Integrated Lightwave Research Group, Department of Electrical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603 (Malaysia); Yetisen, Ali K.; Yun, Seok Hyun [Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, 65 Landsdowne Street, Cambridge, Massachusetts 02139 (United States); Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Dai, Qing [National Center for Nanoscience and Technology, Beijing 100190 (China)


    Periodic highly dense multi-wall carbon nanotube (MWCNT) arrays can act as photonic materials exhibiting band gaps in the visible regime and beyond terahertz range. MWCNT arrays in square arrangement for nanoscale lattice constants can be configured as a microcavity with predictable resonance frequencies. Here, computational analyses of compact square microcavities (≈0.8 × 0.8 μm{sup 2}) in MWCNT arrays were demonstrated to obtain enhanced quality factors (≈170–180) and narrow-band resonance peaks. Cavity resonances were rationally designed and optimized (nanotube geometry and cavity size) with finite element method. Series (1 × 2 and 1 × 3) and parallel (2 × 1 and 3 × 1) combinations of microcavities were modeled and resonance modes were analyzed. Higher order MWCNT microcavities showed enhanced resonance modes, which were red shifted with increasing Q-factors. Parallel microcavity geometries were also optimized to obtain narrow-band tunable filtering in low-loss communication windows (810, 1336, and 1558 nm). Compact series and parallel MWCNT microcavity arrays may have applications in optical filters and miniaturized optical communication devices.

  1. Effect of Strongly Alkaline Electrolyzed Water on Silk Degumming and the Physical Properties of the Fibroin Fiber


    Cao, Ting-Ting; Wang, Yuan-Jing; Zhang, Yu-Qing


    Strongly alkaline electrolyzed water (SAEW) was prepared by electrolysis of tap water in a laboratory-made water electrolyzer. The pH of stored SAEW was stable for more than one month. The hardness of the electrolyzed water was 30% lower and the Na(+) concentration was 18% higher than those of the tap water. Silkworm cocoon shells were boiled in pH 11.50 SAEW at a ratio of 1∶40∼80 (W/V) for 20 min and the sericin layers around the silk fibroin fibers were removed completely. The tensile prope...

  2. Higher-order photon bunching in a semiconductor microcavity

    DEFF Research Database (Denmark)

    Assmann, M.; Veit, F.; Bayer, M.


    in the single-mode emission of a semiconductor microcavity in the weak and strong coupling regimes. The counting statistics of single photons were recorded with picosecond time resolution, allowing quantitative measurement of the few-photon bunching inside light pulses. Our results show bunching behavior...

  3. Pixel-level plasmonic microcavity infrared photodetector (United States)

    Jing, You Liang; Li, Zhi Feng; Li, Qian; Chen, Xiao Shuang; Chen, Ping Ping; Wang, Han; Li, Meng Yao; Li, Ning; Lu, Wei


    Recently, plasmonics has been central to the manipulation of photons on the subwavelength scale, and superior infrared imagers have opened novel applications in many fields. Here, we demonstrate the first pixel-level plasmonic microcavity infrared photodetector with a single quantum well integrated between metal patches and a reflection layer. Greater than one order of magnitude enhancement of the peak responsivity has been observed. The significant improvement originates from the highly confined optical mode in the cavity, leading to a strong coupling between photons and the quantum well, resulting in the enhanced photo-electric conversion process. Such strong coupling from the localized surface plasmon mode inside the cavity is independent of incident angles, offering a unique solution to high-performance focal plane array devices. This demonstration paves the way for important infrared optoelectronic devices for sensing and imaging.

  4. Effect of Strongly Alkaline Electrolyzed Water on Silk Degumming and the Physical Properties of the Fibroin Fiber.

    Directory of Open Access Journals (Sweden)

    Ting-Ting Cao

    Full Text Available Strongly alkaline electrolyzed water (SAEW was prepared by electrolysis of tap water in a laboratory-made water electrolyzer. The pH of stored SAEW was stable for more than one month. The hardness of the electrolyzed water was 30% lower and the Na(+ concentration was 18% higher than those of the tap water. Silkworm cocoon shells were boiled in pH 11.50 SAEW at a ratio of 1∶40∼80 (W/V for 20 min and the sericin layers around the silk fibroin fibers were removed completely. The tensile properties and thermal decomposition temperature of a single filament of silk fibroin obtained by the SAEW method were almost the same as those for the fiber obtained by the neutral soap, and much higher than those for the fiber obtained by Na2CO3 degumming. The results demonstrate that SAEW is an environmentally friendly and pollution-free silk degumming agent that allows highly efficient, low cost recovery of sericin.

  5. Effect of Strongly Alkaline Electrolyzed Water on Silk Degumming and the Physical Properties of the Fibroin Fiber. (United States)

    Cao, Ting-Ting; Wang, Yuan-Jing; Zhang, Yu-Qing


    Strongly alkaline electrolyzed water (SAEW) was prepared by electrolysis of tap water in a laboratory-made water electrolyzer. The pH of stored SAEW was stable for more than one month. The hardness of the electrolyzed water was 30% lower and the Na(+) concentration was 18% higher than those of the tap water. Silkworm cocoon shells were boiled in pH 11.50 SAEW at a ratio of 1∶40∼80 (W/V) for 20 min and the sericin layers around the silk fibroin fibers were removed completely. The tensile properties and thermal decomposition temperature of a single filament of silk fibroin obtained by the SAEW method were almost the same as those for the fiber obtained by the neutral soap, and much higher than those for the fiber obtained by Na2CO3 degumming. The results demonstrate that SAEW is an environmentally friendly and pollution-free silk degumming agent that allows highly efficient, low cost recovery of sericin.

  6. A Strongly Calc-alkaline Suite in the Midst of the Tholeiitic Columbia River Basalt Province: Implications for Generating the Calc-alkaline Trend Without Subduction Processes (United States)

    Steiner, A. R.; Streck, M. J.


    The mid-Miocene lavas of the Strawberry Volcanics (SV), distributed over 3,400 km2 in NE Oregon, comprise a diverse volcanic suite, which span the range of compositions from basalt to rhyolite. The volcanic suite is mainly composed of calc-alkaline (CA) basaltic andesite and andesite, yet tholeiitic (TH) lavas of basalt to andesite occur as well. The SV lies in the heart of nearly coeval flood basalts of the Columbia River province of the Pacific Northwest. The unique combination of strongly CA rocks of the SV in a non-subduction setting provide an excellent opportunity to study controls on inducing CA evolution in the midst of a TH province and independent of processes taking places at an active subduction zone. New 40Ar/39Ar ages indicate CA basaltic andesites to andesites of the SV erupted at least from 14.78±0.13 Ma to 12.44±0.12 Ma demonstrating that CA magmatism of the SV was ongoing during the eruptions of the tholeiitic Wanapum Basalt member of the Columbia River Basalt Group (CRBG). This range will likely be extended to even older ages in the future because existent age dates did not include samples from near the base of the SV. Thickness of intermediate lavas flows of the SV range from 15 m to as thin as 2 m and lavas are characterized by mostly phenocryst poor lithologies. When phenocrysts are abundant they are very small suggesting growth late during eruption. Single lava flow sections can include on the order of 30 conformable flows, testifying to a vigorous eruption history. The thickest andesitic sections are located in the glacially carved mountains of the Strawberry Mountain Wilderness (i.e. Strawberry Mountain, High Lake, and Slide Lake) where several vent complexes are exposed, which are delineated by dikes and plugs with finely interlocking plutonic textures, cross-cutting SV lava flows. Dikes generally strike NW-SE. Subtle variations in major and trace element compositions exist between TH and CA lavas of the SV. The CA lavas of the SV are

  7. Exciton Polaritons in Microcavities New Frontiers

    CERN Document Server

    Sanvitto, Daniele


    In the past decade, there has been a burst of new and fascinating physics associated to the unique properties of two-dimensional exciton polaritons, their recent demonstration of condensation under non-equilibrium conditions and all the related quantum phenomena, which have stimulated extensive research work. This monograph summarizes the current state of the art of research on exciton polaritons in microcavities: their interactions, fast dynamics, spin-dependent phenomena, temporal and spatial coherence, condensation under non-equilibrium conditions, related collective quantum phenomena and most advanced applications. The monograph is written by the most active authors who have strongly contributed to the advances in this area. It is of great interests to both physicists approaching this subject for the first time, as well as a wide audience of experts in other disciplines who want to be updated on this fast moving field.

  8. Tuning a microcavity-coupled terahertz laser

    Energy Technology Data Exchange (ETDEWEB)

    Castellano, Fabrizio; Bianchi, Vezio; Vitiello, Miriam S., E-mail: [NEST, CNR-Istituto Nanoscienze and Scuola Normale Superiore, Piazza San Silvestro 12, 56127 Pisa (Italy); Li, Lianhe; Zhu, Jingxuan; Linfield, Edmund H.; Giles Davies, A. [School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT (United Kingdom); Tredicucci, Alessandro [Dipartimento di Fisica, Università degli Studi di Pisa, Largo Pontecorvo 6, 56127 Pisa (Italy)


    Tunable oscillators are a key component of almost all electronic and photonic systems. Yet, a technology capable of operating in the terahertz (THz)-frequency range and fully suitable for widescale implementation is still lacking. This issue is significantly limiting potential THz applications in gas sensing, high-resolution spectroscopy, hyper-spectral imaging, and optical communications. The THz quantum cascade laser is arguably the most promising solution in terms of output power and spectral purity. In order to achieve reliable, repeatable, and broad tunability, here we exploit the strong coupling between two different cavity mode concepts: a distributed feedback one-dimensional photonic resonator (providing gain) and a mechanically actuated wavelength-size microcavity (providing tuning). The result is a continuously tunable, single-mode emitter covering a 162 GHz spectral range, centered on 3.2 THz. Our source has a few tens of MHz resolution, extremely high differential efficiency, and unprecedented compact and simple design architecture. By unveiling the large potential that lies in this technique, our results provide a robust platform for radically different THz systems exploiting broadly tunable semiconductor lasers.

  9. Biexcitons or bipolaritons in a semiconductor microcavity

    DEFF Research Database (Denmark)

    Borri, Paola; Langbein, Wolfgang Werner; Woggon, U


    A well-resolved nonlinear optical transition associated with biexcitons is observed in a high-quality microcavity with a Rabi splitting exceeding the binding energy of biexcitons in the embedded quantum well. This transition is identified as an induced absorption from the lower polariton to the b......A well-resolved nonlinear optical transition associated with biexcitons is observed in a high-quality microcavity with a Rabi splitting exceeding the binding energy of biexcitons in the embedded quantum well. This transition is identified as an induced absorption from the lower polariton...

  10. Growth of self-assembled (Ga)InAs/GaAs quantum dots and realization of high quality microcavities for experiments in the field of strong exciton photon coupling; Selbstorganisiertes Wachstum von (Ga)InAs/GaAs-Quantenpunkten und Entwicklung von Mikroresonatoren hoechster Guete fuer Experimente zur starken Exziton-Photon-Kopplung

    Energy Technology Data Exchange (ETDEWEB)

    Loeffler, Andreas


    At the beginning, we improved the three dimensional optical confinement of the micropillars. The quality factor of the pillars could be increased by the use of higher reflectivity mirrors and a matched V/III ratio for the different epitaxial layers. Hence, a record quality factor of about 90000 was achieved for an active micropillar with 26 (30) mirror pairs in the top (bottom) DBR and a diameter of 4 {mu}m. In parallel to this, we made studies on the growth of self-assembled GaInAs quantum dots on GaAs substrates. Here, the nucleation of three dimensional islands as well as their optical properties were object of the investigation. The morphological properties of the dots were analyzed by transmission and scanning electron microscopy, and the optical properties were investigated by photoluminescence and photoreflectance measurements. The optical and particularly the morphological properties of the self-assembled GaInAs quantum dots were essentially improved. Due to a low strain nucleation layer with an indium content of 30 %, the dot density could be reduced to 6-9 x 10{sup 9} cm{sup -2} and their geometric dimensions were increased to typical lengths between 50 and 100 nm and widths of about 30 nm. The lattice mismatch between the quantum dots and the surrounding matrix is decreased due to the reduced indium content. The minimized strain during the dot growth leads to an enhanced migration length of the deposited atoms on the surface. Finally, the obtained findings of the MBE growth of microcavities, their fabrication and the self-assembled island growth of GaInAs on GaAs were used for the realization of further samples. Low strain GaInAs quantum dots were embedded into the microresonators. These structures allowed for the first time the observation of strong coupling between light and matter in a semiconductor. In case of the low strain quantum dots with enlarged dimensions in the strong coupling regime, a vacuum Rabi-splitting of about 140 {mu}eV between the

  11. Directional Secondary Emission of a Semiconductor Microcavity

    DEFF Research Database (Denmark)

    Langbein, Wolfgang; Jensen, Jacob Riis; Hvam, Jørn Märcher


    We investigate the time-resolved secondary emission of a homogeneously broadened microcavity after resonant excitation. The sample consists of a 25nm GaAs single quantum well (QW) in the center of a wedged ¥ë cavity with AlAs/AlGaAs Bragg reflectors, grown by molecular beam epitaxy. At zero...

  12. Rayleigh scattering in coupled microcavities: theory. (United States)

    Vörös, Zoltán; Weihs, Gregor


    In this paper we theoretically study how structural disorder in coupled semiconductor heterostructures influences single-particle scattering events that would otherwise be forbidden by symmetry. We extend the model of Savona (2007 J. Phys.: Condens. Matter 19 295208) to describe Rayleigh scattering in coupled planar microcavity structures, and find that effective filter theories can be ruled out.

  13. Ultranarrow polaritons in a semiconductor microcavity

    DEFF Research Database (Denmark)

    Jensen, Jacob Riis; Borri, Paola; Langbein, Wolfgang


    We have achieved a record high ratio (19) of the Rabi splitting (3.6 meV) to the polariton linewidth (190 mu eV), in a semiconductor lambda microcavity with a single 25 nm GaAs quantum well at the antinode. The narrow polariton lines are obtained with a special cavity design which reduces...

  14. Enhancing Coherent Light-Matter Interactions through Microcavity-Engineered Plasmonic Resonances (United States)

    Peng, Pai; Liu, Yong-Chun; Xu, Da; Cao, Qi-Tao; Lu, Guowei; Gong, Qihuang; Xiao, Yun-Feng


    Quantum manipulation is challenging in localized-surface plasmon resonances (LSPRs) due to strong dissipations. To enhance quantum coherence, here we propose to engineer the electromagnetic environment of LSPRs by placing metallic nanoparticles (MNPs) in optical microcavities. An analytical quantum model is first built to describe the LSPR-microcavity interaction, revealing the significantly enhanced coherent radiation and the reduced incoherent dissipation. Furthermore, when a quantum emitter interacts with the LSPRs in the cavity-engineered environment, its quantum yield is enhanced over 40 times and the radiative power over one order of magnitude, compared to those in the vacuum environment. Importantly, the cavity-engineered MNP-emitter system can enter the strong coupling regime of cavity quantum electrodynamics, providing a promising platform for the study of quantum plasmonics, quantum information processing, precise sensing, and spectroscopy.

  15. Synthetic holography based on scanning microcavity

    Directory of Open Access Journals (Sweden)

    A. Di Donato


    Full Text Available Synthetic optical holography (SOH is an imaging technique, introduced in scanning microscopy to record amplitude and phase of a scattered field from a sample. In this paper, it is described a novel implementation of SOH through a lens-free low-coherence system, based on a scanning optical microcavity. This technique combines the low-coherence properties of the source with the mutual interference of scattered waves and the resonant behavior of a micro-cavity, in order to realize a high sensitive imaging system. Micro-cavity is compact and realized by approaching a cleaved optical fiber to the sample. The scanning system works in an open-loop configuration without the need for a reference wave, usually required in interferometric systems. Measurements were performed over calibration samples and a lateral resolution of about 1 μm is achieved by means of an optical fiber with a Numerical Aperture (NA equal to 0.1 and a Mode Field Diameter (MDF of 5.6 μm.

  16. Charged Polaron Polaritons in an Organic Semiconductor Microcavity (United States)

    Cheng, Chiao-Yu; Dhanker, Rijul; Gray, Christopher L.; Mukhopadhyay, Sukrit; Kennehan, Eric R.; Asbury, John B.; Sokolov, Anatoliy; Giebink, Noel C.


    We report strong coupling between light and polaron optical excitations in a doped organic semiconductor microcavity at room temperature. Codepositing MoO3 and the hole transport material 4, 4' -cyclohexylidenebis[N , N -bis(4-methylphenyl)benzenamine] introduces a large hole density with a narrow linewidth optical transition centered at 1.8 eV and an absorption coefficient exceeding 104 cm-1 . Coupling this transition to a Fabry-Pérot cavity mode yields upper and lower polaron polariton branches that are clearly resolved in angle-dependent reflectivity with a vacuum Rabi splitting ℏ ΩR>0.3 eV . This result establishes a path to electrically control polaritons in organic semiconductors and may lead to increased polariton-polariton Coulombic interactions that lower the threshold for nonlinear phenomena such as polariton condensation and lasing.

  17. Hybrid polaritons in a resonant inorganic/organic semiconductor microcavity

    Energy Technology Data Exchange (ETDEWEB)

    Höfner, M., E-mail:; Sadofev, S.; Henneberger, F. [Institut für Physik, Humboldt-Universität zu Berlin, Newtonstr.15, 12489 Berlin (Germany); Kobin, B.; Hecht, S. [Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin (Germany)


    We demonstrated the strong coupling regime in a hybrid inorganic-organic microcavity consisting of (Zn,Mg)O quantum wells and ladder-type oligo(p-phenylene) molecules embedded in a polymer matrix. A Fabry-Pérot cavity is formed by an epitaxially grown lower ZnMgO Bragg reflector and a dielectric mirror deposited atop of the organic layer. A clear anticrossing behavior of the polariton branches related to the Wannier-Mott and Frenkel excitons, and the cavity photon mode with a Rabi-splitting reaching 50 meV, is clearly identified by angular-dependent reflectivity measurements at low temperature. By tailoring the structural design, an equal mixing with weights of about 0.3 for all three resonances is achieved for the middle polariton branch at an incidence angle of about 35°.

  18. Tunable polaritonic molecules in an open microcavity system

    Energy Technology Data Exchange (ETDEWEB)

    Dufferwiel, S.; Li, Feng, E-mail:; Giriunas, L.; Walker, P. M.; Skolnick, M. S.; Krizhanovskii, D. N., E-mail: [Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH (United Kingdom); Trichet, A. A. P.; Smith, J. M. [Department of Materials, University of Oxford, Oxford OX1 3PH (United Kingdom); Farrer, I.; Ritchie, D. A. [Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE (United Kingdom)


    We experimentally demonstrate tunable coupled cavities based upon open access zero-dimensional hemispherical microcavities. The modes of the photonic molecules are strongly coupled with quantum well excitons forming a system of tunable polaritonic molecules. The cavity-cavity coupling strength, which is determined by the degree of modal overlap, is controlled through the fabricated centre-to-centre distance and tuned in-situ through manipulation of both the exciton-photon and cavity-cavity detunings by using nanopositioners to vary the mirror separation and angle between them. We demonstrate micron sized confinement combined with high photonic Q-factors of 31 000 and lower polariton linewidths of 150 μeV at resonance along with cavity-cavity coupling strengths between 2.5 meV and 60 μeV for the ground cavity state.

  19. Bistability and self-oscillations effects in a polariton-laser semiconductor microcavity

    International Nuclear Information System (INIS)

    Cotta, E A; Matinaga, F M


    We report an experimental observation of polaritonic optical bistability of the laser emission in a planar semiconductor microcavity with a 100 0 A GaAs single quantum well in the strong-coupling regime. The bistability curves show crossings that indicate a competition between a Kerr-like effect induced by the polariton population and thermal effects. Associated with the bistability, laser-like emission occurs at the bare cavity mode

  20. Polariton condensation in a strain-compensated planar microcavity with InGaAs quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Cilibrizzi, Pasquale; Askitopoulos, Alexis, E-mail:; Silva, Matteo; Lagoudakis, Pavlos G. [Department of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ (United Kingdom); Bastiman, Faebian; Clarke, Edmund [EPSRC National Centre for III-V Technologies, University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom); Zajac, Joanna M.; Langbein, Wolfgang [School of Physics and Astronomy, Cardiff University, The Parade, Cardiff CF24 3AA (United Kingdom)


    The investigation of intrinsic interactions in polariton condensates is currently limited by the photonic disorder of semiconductor microcavity structures. Here, we use a strain compensated planar GaAs/AlAs{sub 0.98}P{sub 0.02} microcavity with embedded InGaAs quantum wells having a reduced cross-hatch disorder to overcome this issue. Using real and reciprocal space spectroscopic imaging under non-resonant optical excitation, we observe polariton condensation and a second threshold marking the onset of photon lasing, i.e., the transition from the strong to the weak-coupling regime. Condensation in a structure with suppressed photonic disorder is a necessary step towards the implementation of periodic lattices of interacting condensates, providing a platform for on chip quantum simulations.

  1. Scalable photonic quantum computing assisted by quantum-dot spin in double-sided optical microcavity. (United States)

    Wei, Hai-Rui; Deng, Fu-Guo


    We investigate the possibility of achieving scalable photonic quantum computing by the giant optical circular birefringence induced by a quantum-dot spin in a double-sided optical microcavity as a result of cavity quantum electrodynamics. We construct a deterministic controlled-not gate on two photonic qubits by two single-photon input-output processes and the readout on an electron-medium spin confined in an optical resonant microcavity. This idea could be applied to multi-qubit gates on photonic qubits and we give the quantum circuit for a three-photon Toffoli gate. High fidelities and high efficiencies could be achieved when the side leakage to the cavity loss rate is low. It is worth pointing out that our devices work in both the strong and the weak coupling regimes.

  2. Micro-Cavity Fluidic Dye Laser

    DEFF Research Database (Denmark)

    Helbo, Bjarne; Kristensen, Anders; Menon, Aric Kumaran


    We have successfully designed, fabricated and characterized a micro-cavity fluidic dye laser with metallic mirrors, which can be integrated with polymer based lab-on-a-chip microsystems without further processing steps. A simple rate-equation model is used to predict the average pumping power...... threshold for lasing as function of cavity-mirror reflectance, laser dye concentration and cavity length. The laser device is characterized using the laser dye Rhodamine 6G dissolved in ethanol. Lasing is observed, and the influence of dye concentration is investigated....

  3. Optical micro-cavities on silicon (United States)

    Dai, Daoxin; Liu, Erhu; Tan, Ying


    Silicon-based optical microcavities are very popular for many applications because of the ultra-compact footprint, easy scalability, and functional versatility. In this paper we give a discussion about the challenges of the optical microcavities on silicon and also give a review of our recent work, including the following parts. First, a near-"perfect" high-order MRR optical filter with a box-like filtering response is realized by introducing bent directional couplers to have sufficient coupling between the access waveguide and the microrings. Second, an efficient thermally-tunable MRR-based optical filter with graphene transparent nano-heater is realized by introducing transparent graphene nanoheaters. Thirdly, a polarization-selective microring-based optical filter is realized to work with resonances for only one of TE and TM polarizations for the first time. Finally, a on-chip reconfigurable optical add-drop multiplexer for hybrid mode- /wavelength-division-multiplexing systems is realized for the first time by monolithically integrating a mode demultiplexer, four MRR optical switches, and a mode multiplexer.

  4. Non-Markovian decay and lasing condition in an optical microcavity coupled to a structured reservoir

    International Nuclear Information System (INIS)

    Longhi, Stefano


    The decay dynamics of the classical electromagnetic field in a leaky optical resonator supporting a single mode coupled to a structured continuum of modes (reservoir) is theoretically investigated, and the issue of threshold condition for lasing in presence of an inverted medium is comprehensively addressed. Specific analytical results are given for a single-mode microcavity resonantly coupled to a coupled resonator optical waveguide, which supports a band of continuous modes acting as decay channels. For weak coupling, the usual exponential Weisskopf-Wigner (Markovian) decay of the field in the bare resonator is found, and the threshold for lasing increases linearly with the coupling strength. As the coupling between the microcavity and the structured reservoir increases, the field decay in the passive cavity shows nonexponential features, and correspondingly the threshold for lasing ceases to increase, reaching a maximum and then starting to decrease as the coupling strength is further increased. A singular behavior for the 'laser phase transition', which is a clear signature of strong non-Markovian dynamics, is found at critical values of the coupling between the microcavity and the reservoir

  5. Phase sensitive properties and coherent manipulation of a photonic crystal microcavity. (United States)

    Quiring, Wadim; Jonas, Björn; Förstner, Jens; Rai, Ashish K; Reuter, Dirk; Wieck, Andreas D; Zrenner, Artur


    We present phase sensitive cavity field measurements on photonic crystal microcavities. The experiments have been performed as autocorrelation measurements with ps double pulse laser excitation for resonant and detuned conditions. Measured E-field autocorrelation functions reveal a very strong detuning dependence of the phase shift between laser and cavity field and of the autocorrelation amplitude of the cavity field. The fully resolved phase information allows for a precise frequency discrimination and hence for a precise measurement of the detuning between laser and cavity. The behavior of the autocorrelation amplitude and phase and their detuning dependence can be fully described by an analytic model. Furthermore, coherent control of the cavity field is demonstrated by tailored laser excitation with phase and amplitude controlled pulses. The experimental proof and verification of the above described phenomena became possible by an electric detection scheme, which employs planar photonic crystal microcavity photo diodes with metallic Schottky contacts in the defect region of the resonator. The applied photo current detection was shown to work also efficiently at room temperature, which make electrically contacted microcavities attractive for real world applications.

  6. Rabi-like splitting from large area plasmonic microcavity

    Directory of Open Access Journals (Sweden)

    Fatemeh Hosseini Alast


    Full Text Available Rabi-like splitting was observed from a hybrid plasmonic microcavity. The splitting comes from the coupling of cavity mode with the surface plasmon polariton mode; anti-crossing was observed alongside the modal conversional channel on the reflection light measurement. The hybrid device consists of a 10x10 mm2 ruled metal grating integrated onto the Fabry-Perot microcavity. The 10x10 mm2 ruled metal grating fabricated from laser interference and the area is sufficiently large to be used in the practical optical device. The larger area hybrid plasmonic microcavity can be employed in polariton lasers and biosensors.

  7. Enhancement of UV Excited Photoluminescence by Fabry-Perot Microcavity

    Directory of Open Access Journals (Sweden)

    Chunxian Tao


    Full Text Available A light-emitting microcavity with the structure of dielectric mirror/phosphor coating/dielectric mirror for the enhancement of PL efficiency excited under UV light was designed and fabricated. The fluorescence emission of Lumogen S0795 coating within microcavity structure is significantly enhanced compared with the coating on bare substrate. The measurement results indicate the possibility of developing front illuminated CCD based on optical resonant cavity for UV-visible imaging with higher sensitivity.

  8. Parity-Time-Symmetric Whispering-Gallery Microcavities (United States)


    Nature Photon. 4, 46–49 (2010). 48. Dantham, V. R. et al. Label-free detection of single protein using a nanoplasmonic-photonic hybrid microcavity. Nano ...microcavities. μR1: active microtoroid; μR2: passive microtoroid; PD: photodetector; WDM: wavelength division multiplexer; FC: fiber connector; TEC ...resonators and fiber tapers as well as between the directly-coupled active and passive resonators. 5) Thermoelectric cooler ( TEC ) used to tune

  9. Influence of Experimental Parameters Using the Dip-Coating Method on the Barrier Performance of Hybrid Sol-Gel Coatings in Strong Alkaline Environments

    Directory of Open Access Journals (Sweden)

    Rita B. Figueira


    Full Text Available Previous studies have shown that the barrier effect and the performance of organic-inorganic hybrid (OIH sol-gel coatings are highly dependent on the coating deposition method as well as on the processing conditions. However, studies on how the coating deposition method influences the barrier properties in alkaline environments are scarce. The aim of this experimental research was to study the influence of experimental parameters using the dip-coating method on the barrier performance of an OIH sol-gel coating in contact with simulated concrete pore solutions (SCPS. The influence of residence time (Rt, a curing step between each dip step and the number of layers of sol-gel OIH films deposited on hot-dip galvanized steel to prevent corrosion in highly alkaline environments was studied. The barrier performance of these OIH sol-gel coatings, named U(400, was assessed in the first instants of contact with SCPS, using electrochemical impedance spectroscopy and potentiodynamic methods. The durability and stability of the OIH coatings in SCPS was monitored during eight days by macrocell current density. The morphological characterization of the surface was performed by Scanning Electronic Microscopy before and after exposure to SCPS. Glow Discharge Optical Emission Spectroscopy was used to investigate the thickness of the U(400 sol-gel coatings as a function of the number of layers deposited with and without Rt in the coatings thickness.

  10. Microcavity single virus detection and sizing with molecular sensitivity (United States)

    Dantham, V. R.; Holler, S.; Kolchenko, V.; Wan, Z.; Arnold, S.


    We report the label-free detection and sizing of the smallest individual RNA virus, MS2 by a spherical microcavity. Mass of this virus is ~6 ag and produces a theoretical resonance shift ~0.25 fm upon adsorbing an individual virus at the equator of the bare microcavity, which is well below the r.m.s background noise of 2 fm. However, detection was accomplished with ease (S/N = 8, Q = 4x105) using a single dipole stimulated plasmonic-nanoshell as a microcavity wavelength shift enhancer. Analytical expressions based on the "reactive sensing principle" are developed to extract the radius of the virus from the measured signals. Estimated limit of detection for these experiments was ~0.4 ag or 240 kDa below the size of all known viruses, largest globular and elongated proteins [Phosphofructokinase (345 kDa) and Fibrinogen (390 kDa), respectively].

  11. Mixed-potential Behavior of Nanostructured RuO2 Sensing Electrode of Water Quality Sensors in Strong Alkaline Solutions at a Temperature Range of 9-30° C (United States)

    Zhuiykov, Serge


    Mixed-potential behavior of the water quality monitoring sensors using nanostructured RuO2 sensing electrode (SE) has been observed in strong alkaline solutions at dissolved oxygen (DO) measurements in the temperature range of 9-30° C. This behavior indicated that a Faradaic oxygen reduction reaction becomes not only a one-electron process, which is typical for DO measurements at a neutral pH, but rather multi-step process with superoxide oxygen ions (O2-), OH- and RuO42- ions involvement. The DO sensing characteristics were examined in the pH range of 2.0-13.0. The measured emf at strong alkaline solutions is a mixed potential from the reactions involved RuO42- and OH- ions and DO. Impedance spectroscopy was employed for confirmation the mixed-potential behavior of the sensor. It was also found during experiments that OH- ions influence the response/recovery rate of the SE reactions as the pH of water increases.

  12. Coherent dynamics of biexcitons in a semiconductor microcavity

    DEFF Research Database (Denmark)

    Borri, P.; Langbein, W.; Woggon, U.


    The dephasing time of biexcitons in a semiconductor quantum well microcavity is measured at low temperature using transient four-wave mixing spectroscopy. The homogeneous linewidth corresponding to the dephasing of the transition from the crystal ground state to the biexciton is found to be appro......The dephasing time of biexcitons in a semiconductor quantum well microcavity is measured at low temperature using transient four-wave mixing spectroscopy. The homogeneous linewidth corresponding to the dephasing of the transition from the crystal ground state to the biexciton is found...

  13. High-Q submicron-diameter quantum-dot microcavity pillars for cavity QED experiments

    DEFF Research Database (Denmark)

    Gregersen, Niels; Lermer, Matthias; Dunzer, Florian

    As/AlAs micropillar design where Bloch-wave engineering is employed to significally enhance the cavity mode confinement in the submicron diameter regime. We demonstrate a record-high vacuum Rabi splitting of 85 µeV of the strong coupling for pillars incorporating quantum dots with modest oscillator strength f ≈ 10....... It is well-known that light-matter interaction depends on the photonic environment, and thus proper engineering of the optical mode in microcavity systems is central to obtaining the desired functionality. In the strong coupling regime, the visibility of the Rabi splitting is described by the light...... coupling in micropillars relied on quantum dots with high oscillator strengths f > 50, our advanced design allows for the observation of strong coupling for submicron diameter quantum dot-pillars with standard f ≈ 10 oscillator strength. A quality factor of 13600 and a vacuum Rabi splitting of 85 µe...

  14. A new microcavity design for single molecule detection

    International Nuclear Information System (INIS)

    Steiner, M.; Schleifenbaum, F.; Stupperich, C.; Failla, A.V.; Hartschuh, A.; Meixner, A.J.


    We present a new microcavity design which allows for efficient detection of single molecules by measuring the molecular fluorescence emission coupled into a resonant cavity mode. The Fabry-Perot-type microresonator consists of two silver mirrors separated by a thin polymer film doped with dye molecules in ultralow concenctration. By slightly tilting one of the mirrors different cavity lengths can be selected within the same sample. Locally, on a μm scale, the microcavity still acts as a planar Fabry-Perot resonator. Using scanning confocal fluorescence microscopy, single emitters on resonance with a single mode of the microresonator can be spatially addressed. Our microcavity is demonstrated to be well-suited for investigating the coupling mechanism between single quantum emitters and single modes of the electromagnetic field. The microcavity layout could be integrated in a lab-on-a-microchip design for ultrasensitive microfluidic analytics and can be considered as an important improvement for single photon sources based on single molecules operating at room temperature

  15. Computational Modeling of Photonic Crystal Microcavity Single-Photon Emitters (United States)

    Saulnier, Nicole A.

    Conventional cryptography is based on algorithms that are mathematically complex and difficult to solve, such as factoring large numbers. The advent of a quantum computer would render these schemes useless. As scientists work to develop a quantum computer, cryptographers are developing new schemes for unconditionally secure cryptography. Quantum key distribution has emerged as one of the potential replacements of classical cryptography. It relics on the fact that measurement of a quantum bit changes the state of the bit and undetected eavesdropping is impossible. Single polarized photons can be used as the quantum bits, such that a quantum system would in some ways mirror the classical communication scheme. The quantum key distribution system would include components that create, transmit and detect single polarized photons. The focus of this work is on the development of an efficient single-photon source. This source is comprised of a single quantum dot inside of a photonic crystal microcavity. To better understand the physics behind the device, a computational model is developed. The model uses Finite-Difference Time-Domain methods to analyze the electromagnetic field distribution in photonic crystal microcavities. It uses an 8-band k · p perturbation theory to compute the energy band structure of the epitaxially grown quantum dots. We discuss a method that combines the results of these two calculations for determining the spontaneous emission lifetime of a quantum dot in bulk material or in a microcavity. The computational models developed in this thesis are used to identify and characterize microcavities for potential use in a single-photon source. The computational tools developed are also used to investigate novel photonic crystal microcavities that incorporate 1D distributed Bragg reflectors for vertical confinement. It is found that the spontaneous emission enhancement in the quasi-3D cavities can be significantly greater than in traditional suspended slab

  16. Optical properties of semiconductors quantum microcavity structures

    International Nuclear Information System (INIS)

    Afshar, A.M.


    The principal phenomenon investigated in this thesis is vacuum Rabi coupling in semiconductor microcavity structures. In these structures quantum well excitons are embedded in a Fabry - Perot like cavity, defined by two semiconductor dielectric mirrors. In such a system the coupled exciton and cavity photon mode form a mixed - mode polariton, where on - resonance there are two branches, each having 50% exciton and 50% photon character. The separation between the upper and lower branches is a measure of the coupling strength where the strength is dependent on the exciton oscillator strength. This interaction is known as vacuum Rabi coupling, and clear anticrossing is seen when the exciton is tuned through the cavity. In our reflectivity experiments we demonstrate control of the coupling between the cavity mode and the exciton by varying temperature, applied electric or magnetic field. Modelling of the reflectivity spectra and the tuning was done using a Transfer Matrix Reflectivity (TMR) model or a linear dispersion model, where in both cases the excitons are treated as Lorentz oscillators. Temperature tuning is achieved because exciton energy decreases with temperature at a much faster rate than the cavity mode. We have demonstrated vacuum Rabi coupling of the cavity mode with both the heavy - hole and light - hole excitons. Electric field tuning is achieved via the quantum confined Stark effect which decreases the exciton energy with increasing field, whilst at the same time the cavity mode energy remains constant. A study of how the electric field reduction of exciton oscillator strength reduces the vacuum Rabi coupling strength is performed. We report the first observation in a semiconductor structure of motional narrowing, seen in both electric field and in temperature tuning experiments at high magnetic field. In magnetic field studies we show how magnetic field induced increase in exciton oscillator strength affects the vacuum Rabi coupling. We also show by

  17. High-Q hybrid 3D-2D slab-3D photonic crystal microcavity. (United States)

    Tang, Lingling; Yoshie, Tomoyuki


    The radiation loss in the escaping light cone with a two-dimensional (2D) photonic crystal slab microcavity can be suppressed by means of cladding the low-Q slab microcavity by three-dimensional woodpile photonic crystals with the complete bandgap when the resonance frequency is located inside the complete bandgap. It is confirmed that the hybrid microcavity based on a low-Q, single-defect photonic crystal slab microcavity shows improvement of the Q factor without affecting the mode volume and modal frequency. Whereas 2D slab microcavities exhibit Q saturation with an increase in the number of layers, for the analyzed hybrid microcavities with a small gap between the slab and woodpiles, the Q factor does not saturate.

  18. Photoacoustic microscopy achieved by microcavity synchronous parallel acquisition technique. (United States)

    Tan, Zhiliang; Liao, Yanfei; Wu, Yongbo; Tang, Zhilie; Wang, Ruikang K


    We report on a sub-cellular resolution photoacoustic microscopy (PAM) system that employs microcavity synchronous parallel acquisition technique for detecting the weak photoacoustic (PA) signal excited by a modulated continuous wave (CW) laser source. The gas microcavity transducer is developed based on the fact that the bulk modulus of the gas is far less than the solid and the change of the air-gas pressure is inversely proportional to the gas volume, making it extremely sensitive to the tiny PA pressure wave. Besides, considering PA wave expends in various directions, detecting PA signals from different position and adding them together can increase the detecting sensitivity and the signal to noise ratio(SNR), then we employs two microphone to acquire PA wave synchronously and parallelly. We show that the developed PAM system is capable of label-free imaging and differentiating of the hemoglobin distribution within single red blood cells under normal and anemia conditions.

  19. Exceptional points enhance sensing in an optical microcavity (United States)

    Chen, Weijian; Kaya Özdemir, Şahin; Zhao, Guangming; Wiersig, Jan; Yang, Lan


    Sensors play an important part in many aspects of daily life such as infrared sensors in home security systems, particle sensors for environmental monitoring and motion sensors in mobile phones. High-quality optical microcavities are prime candidates for sensing applications because of their ability to enhance light-matter interactions in a very confined volume. Examples of such devices include mechanical transducers, magnetometers, single-particle absorption spectrometers, and microcavity sensors for sizing single particles and detecting nanometre-scale objects such as single nanoparticles and atomic ions. Traditionally, a very small perturbation near an optical microcavity introduces either a change in the linewidth or a frequency shift or splitting of a resonance that is proportional to the strength of the perturbation. Here we demonstrate an alternative sensing scheme, by which the sensitivity of microcavities can be enhanced when operated at non-Hermitian spectral degeneracies known as exceptional points. In our experiments, we use two nanoscale scatterers to tune a whispering-gallery-mode micro-toroid cavity, in which light propagates along a concave surface by continuous total internal reflection, in a precise and controlled manner to exceptional points. A target nanoscale object that subsequently enters the evanescent field of the cavity perturbs the system from its exceptional point, leading to frequency splitting. Owing to the complex-square-root topology near an exceptional point, this frequency splitting scales as the square root of the perturbation strength and is therefore larger (for sufficiently small perturbations) than the splitting observed in traditional non-exceptional-point sensing schemes. Our demonstration of exceptional-point-enhanced sensitivity paves the way for sensors with unprecedented sensitivity.

  20. Seeding Dynamics of Nonlinear Polariton Emission from a Microcavity

    DEFF Research Database (Denmark)

    Østergaard, John Erland; Langbein, Wolfgang Werner; Jensen, Jacob Riis


    Summary form only given. The dynamics of polaritons in microcavity samples is presently under intense debate, in particular whether or not the so-called Boser action is possible. In this work, we investigate a λ cavity with a homogeneously broadened 25 nm GaAs quantum well at the antinode...... at a temperature of 10 K. We can thus inject well-defined polariton populations in k-space revealing how different initial and final state populations may influence the dynamics....

  1. Distinguishing autocrine and paracrine signals in hematopoietic stem cell culture using a biofunctional microcavity platform (United States)

    Müller, Eike; Wang, Weijia; Qiao, Wenlian; Bornhäuser, Martin; Zandstra, Peter W.; Werner, Carsten; Pompe, Tilo


    Homeostasis of hematopoietic stem cells (HSC) in the mammalian bone marrow stem cell niche is regulated by signals of the local microenvironment. Besides juxtacrine, endocrine and metabolic cues, paracrine and autocrine signals are involved in controlling quiescence, proliferation and differentiation of HSC with strong implications on expansion and differentiation ex vivo as well as in vivo transplantation. Towards this aim, a cell culture analysis on a polymer microcavity carrier platform was combined with a partial least square analysis of a mechanistic model of cell proliferation. We could demonstrate the discrimination of specific autocrine and paracrine signals from soluble factors as stimulating and inhibitory effectors in hematopoietic stem and progenitor cell culture. From that we hypothesize autocrine signals to be predominantly involved in maintaining the quiescent state of HSC in single-cell niches and advocate our analysis platform as an unprecedented option for untangling convoluted signaling mechanisms in complex cell systems being it of juxtacrine, paracrine or autocrine origin.

  2. Purcell effect in an organic-inorganic halide perovskite semiconductor microcavity system

    International Nuclear Information System (INIS)

    Wang, Jun; Wang, Yafeng; Hu, Tao; Wu, Lin; Shen, Xuechu; Chen, Zhanghai; Cao, Runan; Xu, Fei; Da, Peimei; Zheng, Gengfeng; Lu, Jian


    Organic-inorganic halide perovskite semiconductors with the attractive physics properties, including strong photoluminescence (PL), huge oscillator strengths, and low nonradiative recombination losses, are ideal candidates for studying the light-matter interaction in nanostructures. Here, we demonstrate the coupling of the exciton state and the cavity mode in the lead halide perovskite microcavity system at room temperature. The Purcell effect in the coupling system is clearly observed by using angle-resolved photoluminescence spectra. Kinetic analysis based on time-resolved PL reveals that the spontaneous emission rate of the halide perovskite semiconductor is significantly enhanced at resonance of the exciton energy and the cavity mode. Our results provide the way for developing electrically driven organic polariton lasers, optical devices, and on-chip coherent quantum light sources

  3. Schottky MSM junctions for carrier depletion in silicon photonic crystal microcavities. (United States)

    Haret, Laurent-Daniel; Checoury, Xavier; Bayle, Fabien; Cazier, Nicolas; Boucaud, Philippe; Combrié, Sylvain; de Rossi, Alfredo


    Collection of free carriers is a key issue in silicon photonics devices. We show that a lateral metal-semiconductor-metal Schottky junction is an efficient and simple way of dealing with that issue in a photonic crystal microcavity. Using a simple electrode design, and taking into account the optical mode profile, the resulting carrier distribution in the structure is calculated. We show that the corresponding effective free carrier lifetime can be reduced by 50 times when the bias is tuned. This allows one to maintain a high cavity quality factor under strong optical injection. In the fabricated structures, carrier depletion is correlated with transmission spectra and directly visualized by Electron Beam Induced Current pictures. These measurements demonstrate the validity of this carrier extraction principle. The design can still be optimized in order to obtain full carrier depletion at a smaller energy cost.

  4. Optical fiber temperature sensor based on a microcavity with polymer overlay. (United States)

    Hernández-Romano, Iván; Cruz-Garcia, Miguel A; Moreno-Hernández, Carlos; Monzón-Hernández, David; López-Figueroa, Efraín O; Paredes-Gallardo, Omar E; Torres-Cisneros, Miguel; Villatoro, Joel


    An ultracompact, cost-effective, and highly accurate fiber optic temperature sensor is proposed and demonstrated. The sensing head consists of Fabry-Perot microcavity formed by an internal mirror made of a thin titanium dioxide (TiO 2 ) film and a microscopic segment of single-mode fiber covered with Poly(dimethylsiloxane) (PDMS). Due to the high thermo-optic coefficient of PDMS the reflectance of the fiber-PDMS interface varies strongly with temperature which in turn modifies the amplitude of the interference pattern. To quantify the changes of the latter we monitored the visibility of the interference pattern and analyzed it by means of the fast Fourier transform. Our sensor exhibits linear response, high sensitivity, and response time of 14 seconds. We believe that the microscopic dimensions along with the performance of the sensor here presented makes it appealing for sensing temperature in PDMS microfluidic circuits or in biological applications.

  5. Modeling of optical fields in laser microcavities using a modal method

    DEFF Research Database (Denmark)

    Gregersen, Niels


    , the cavity should allow for efficient out-coupling of light, which in low-V systems represents an additional design challenge. Engineering a microcavity meeting these demands requires a in-depth physical under-standing of the governing physical mechanisms of the system. In the low-V cavity, a central...... mechanism limiting the Q factor is the poor modal overlap between the cavity Bloch mode and the mirror Bloch mode. Also, the strong connement will generally lead to highly divergent far field patterns and thus low collection efficiency. In this scenario, Bloch-wave engineering [1] and the introduction...... of adiabatic transitions emerge as powerful design tools to control the optical mode. In the modal method, the eld is expanded on the eigenmodes of z-invariant layers and on the Bloch modes of periodic sections. Using mode matching at the interfaces, the method gives direct access to re ection and transmission...

  6. The Coupling of Zero-Dimensional Exciton and Photon States: A Quantum Dot in a Spherical Microcavity (United States)


    the electric 179 180 Microcavity and Photonic Cristal (a) (b) _..•rQ Fig. 1. (a) A schematic diagram of a spherical microcavity with a quantum dot at...core is 2.7 while the refractive indices 182 Microcavity and Photonic Cristal of the layers forming the Bragg reflector are 1.45 and 2.7 and correspond

  7. 1.5 MU M Fabry-Perot Microcavities Based on Hydrogenated Silicon and Related Materials (United States)


    limited by sensitivity of InGaAs photodiode. A sharp 1.54 jtm peak corresponds to a resonant mode of the MC. 167 168 Microcavity and Photonic Cristal A C B...transmission spectra are found to be close to each other in agreement with our theoretical analysis. 170 Microcavity and Photonic Cristal 2. Conclusions In

  8. Bragg polaritons in a ZnSe-based unfolded microcavity at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Sebald, K.; Rahman, SK. S.; Cornelius, M.; Kaya, T.; Gutowski, J. [Semiconductor Optics, Institute of Solid State Physics, University of Bremen, 28334 Bremen (Germany); Klein, T.; Gust, A.; Hommel, D. [Semiconductor Epitaxy, Institute of Solid State Physics, University of Bremen, 28334 Bremen (Germany); Klembt, S. [Institut Néel, Université Grenoble Alpes and CNRS, B.P. 166, 38042 Grenoble (France)


    In this contribution, we present strong coupling of ZnSe quantum well excitons to Bragg modes resulting in the formation of Bragg polariton eigenstates, characterized by a small effective mass in comparison to a conventional microcavity. We observe an anticrossing of the excitonic and the photonic component in our sample being a clear signature for the strong-coupling regime. The anticrossing is investigated by changing the detuning between the excitonic components and the Bragg mode. We find anticrossings between the first Bragg mode and the heavy- as well as light-hole exciton, respectively, resulting in three polariton branches. The observed Bragg-polariton branches are in good agreement with theoretical calculations. The strong indication for the existence of strong coupling is traceable up to a temperature of 200 K, with a Rabi-splitting energy of 24 meV and 13 meV for the Bragg mode with the heavy- and light-hole exciton, respectively. These findings demonstrate the advantages of this sample configuration for ZnSe-based devices for the strong coupling regime.

  9. Pump-Power-Driven Mode Switching in a Microcavity Device and Its Relation to Bose-Einstein Condensation

    Directory of Open Access Journals (Sweden)

    H. A. M. Leymann


    Full Text Available We investigate the switching of the coherent emission mode of a bimodal microcavity device, occurring when the pump power is varied. We compare experimental data to theoretical results and identify the underlying mechanism based on the competition between the effective gain, on the one hand, and the intermode kinetics, on the other. When the pumping is ramped up, above a threshold, the mode with the largest effective gain starts to emit coherent light, corresponding to lasing. In contrast, in the limit of strong pumping, it is the intermode kinetics that determines which mode acquires a large occupation and shows coherent emission. We point out that this latter mechanism is akin to the equilibrium Bose-Einstein condensation of massive bosons. Thus, the mode switching in our microcavity device can be viewed as a minimal instance of Bose-Einstein condensation of photons. Moreover, we show that the switching from one cavity mode to the other always occurs via an intermediate phase where both modes are emitting coherent light and that it is associated with both superthermal intensity fluctuations and strong anticorrelations between both modes.

  10. Electrically-detected ESR in silicon nanostructures inserted in microcavities

    Energy Technology Data Exchange (ETDEWEB)

    Bagraev, Nikolay; Danilovskii, Eduard; Gets, Dmitrii; Klyachkin, Leonid; Kudryavtsev, Andrey; Kuzmin, Roman; Malyarenko, Anna [Ioffe Physical Technical Institute, Polytekhnicheskaya 26, 194021 St. Petersburg (Russian Federation); Gehlhoff, Wolfgang [Technische Universitaet Berlin, D-10623, Berlin (Germany); Mashkov, Vladimir; Romanov, Vladimir [Petersburg State Polytechnical University, Polytekhnicheskaya 29, 195251 St. Petersburg (Russian Federation)


    We present the first findings of the new electrically-detected electron spin resonance technique (EDESR), which reveal the point defects in the ultra-narrow silicon quantum wells (Si-QW) confined by the superconductor δ- barriers. This technique allows the ESR identification without application of an external cavity, as well as a high frequency source and recorder, and with measuring the only response of the magnetoresistance, with internal GHz Josephson emission within frameworks of the normal-mode coupling (NMC) caused by the microcavities embedded in the Si-QW plane.

  11. Coherent generation of acoustic phonons in an optical microcavity

    International Nuclear Information System (INIS)

    Lanzillotti-Kimura, N D; Fainstein, A; Huynh, A; Perrin, B; Jusserand, B; Miard, A; LemaItre, A


    Coherent acoustic phonons confined in a nanocavity are generated in an optical microcavity. The confinement of the femtosecond light pulse in the optical resonator amplifies both processes, generation and detection of the acoustic phonons. In addition, due to the standing wave character of the photon field, phonons of wavevector q = 0 and q = 2k (k is the light wavenumber) contribute to both the generation and detection in time resolved reflectivity measurements, further optimizing the pump and probe experiments. Time resolved differential reflectivity experiments are reported as a function of laser energy. The optical cavity resonance is apparent in the amplitude and spectral features of the Fourier transformed signals

  12. Multi-Valued Spin Switch in a Semiconductor Microcavity (United States)

    Paraïso, T. K.; Wouters, M.; Léger, Y.; Morier-Genoud, F.; Deveaudhyphen; Plédran, B.


    In this work, we report on the first realization of multi-valued spin switching in the solid-state. We investigate the physics of spinor bistability with microcavity polaritons in a trap. Spinor interactions lead to special bistability regimes with decoupled thresholds for spin-up and spin-down polaritons. This allows us to establish state-of-the-art spin switching operations. We evidence polarization hysteresis and determine appropriate conditions to achieve spin multistability. For a given excitation condition, three stable spin states coexist for the system. These results open new pathways for the development of innovative spin-based logic gates and memory devices.

  13. Dispersion engineering for vertical microcavities using subwavelength gratings. (United States)

    Wang, Zhaorong; Zhang, Bo; Deng, Hui


    We show that the energy-momentum dispersion of a vertical semiconductor microcavity can be modified by design using a high-index-contrast subwavelength grating (SWG) as a cavity mirror. We analyze the angular dependence of the reflection phase of the SWG to illustrate the principles of dispersion engineering. We show examples of engineered dispersions such as ones with much reduced or increased energy density of states and one with a double-well-shaped dispersion. This method of dispersion engineering is compatible with maintaining a high cavity quality factor and incorporating fully protected active media inside the cavity, thus enabling the creation of new types of cavity quantum electrodynamics systems.

  14. Composite modulation of Fano resonance in plasmonic microstructures by electric-field and microcavity

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Fan; Wu, Chenyun; Yang, Hong [State Key Laboratory for Mesoscopic Physics and Department of Physics, Peking University, Beijing 100871 (China); Hu, Xiaoyong, E-mail:; Gong, Qihuang [State Key Laboratory for Mesoscopic Physics and Department of Physics, Peking University, Beijing 100871 (China); Collaborative Innovation Center of Quantum Matter, Beijing 100871 (China)


    Composite modulation of Fano resonance by using electric-field and microcavity simultaneously is realized in a plasmonic microstructure, which consists of a gold nanowire grating inserted into a Fabry-Perot microcavity composited of a liquid crystal layer sandwiched between two indium tin oxide layers. The Fano resonance wavelength varies with the applied voltage and the microcavity resonance. A large shift of 48 nm in the Fano resonance wavelength is achieved when the applied voltage is 20 V. This may provide a new way for the study of multi-functional integrated photonic circuits and chips based on plasmonic microstructures.

  15. Composite modulation of Fano resonance in plasmonic microstructures by electric-field and microcavity

    International Nuclear Information System (INIS)

    Zhang, Fan; Wu, Chenyun; Yang, Hong; Hu, Xiaoyong; Gong, Qihuang


    Composite modulation of Fano resonance by using electric-field and microcavity simultaneously is realized in a plasmonic microstructure, which consists of a gold nanowire grating inserted into a Fabry-Perot microcavity composited of a liquid crystal layer sandwiched between two indium tin oxide layers. The Fano resonance wavelength varies with the applied voltage and the microcavity resonance. A large shift of 48 nm in the Fano resonance wavelength is achieved when the applied voltage is 20 V. This may provide a new way for the study of multi-functional integrated photonic circuits and chips based on plasmonic microstructures

  16. Sharply directed emission in microcavity organic light-emitting diodes with a cholesteric liquid crystal film (United States)

    Jeong, Soon Moon; Takanishi, Yoichi; Ishikawa, Ken; Nishimura, Suzushi; Suzaki, Goroh; Takezoe, Hideo


    A flexible microcavity organic light-emitting diode (OLED) was fabricated and the emitting characteristics were examined. A pair of right- and left-handed cholesteric liquid crystal (CLC) films were attached to the microcavity OLED between aluminum (Al) and silver (Ag). Sharply directed spontaneous emission was observed from microcavity OLEDs, in which a typical luminescent material, 8-hydroxyquinoline aluminum (Alq 3), with a broad emission spectrum was used for emitting layer. The introduction of the CLC film improved both the emission bandwidth and directionality, preserving the turn-on voltage and maximum brightness.

  17. Optical properties of microcavities and patterned waveguides

    CERN Document Server

    Culshaw, I S


    electromagnetic fields. The theoretical and measured spectra are shown to be in excellent agreement. The fitting process enabled the full set of structural parameters to be determined. The photonic dispersions of the modes of the PWGs are shown to be closely related to the calculated band structure of an idealised photonic crystal waveguide (PCW) model, namely a PC of finite thickness clad on either side by perfectly reflecting walls. The photonic bands of the ideal 2-D PCW are of mixed polarisation character owing to TE-TM/TM-TE scattering processes. Strong evidence is found to support this in the reflectivity of the 2-D PWG. Polarisation mixing leads to an anti-crossing of photonic bands of the ideal 2-D PCW, and hence the appearance of heavy photon states, away from the boundaries of the 2-D Brillouin zone. Theoretically, the coupling of external radiation to such heavy photon states is shown to occur for the 2-D PWG. A series of new PWG structures employing thin metallic films are proposed in order to all...

  18. Anomalous dispersion of microcavity trion-polaritons (United States)

    Dhara, S.; Chakraborty, C.; Goodfellow, K. M.; Qiu, L.; O'Loughlin, T. A.; Wicks, G. W.; Bhattacharjee, Subhro; Vamivakas, A. N.


    The strong coupling of excitons to optical cavities has provided new insights into cavity quantum electrodynamics as well as opportunities to engineer nanoscale light-matter interactions. Here we study the interaction between out-of-equilibrium cavity photons and both neutral and negatively charged excitons, by embedding a single layer of the atomically thin semiconductor molybdenum diselenide in a monolithic optical cavity based on distributed Bragg reflectors. The interactions lead to multiple cavity polariton resonances and anomalous band inversion for the lower, trion-derived, polariton branch--the central result of the present work. Our theoretical analysis reveals that many-body effects in an out-of-equilibrium setting result in an effective level attraction between the exciton-polariton and trion-polariton accounting for the experimentally observed inverted trion-polariton dispersion. Our results suggest a pathway for studying interesting regimes in quantum many-body physics yielding possible new phases of quantum matter as well as fresh possibilities for polaritonic device architectures.

  19. Sensitive Detection of Individual Neutral Atoms in a Strong Coupling Cavity QED System

    International Nuclear Information System (INIS)

    Zhang Peng-Fei; Zhang Yu-Chi; Li Gang; Du Jin-Jin; Zhang Yan-Feng; Guo Yan-Qiang; Wang Jun-Min; Zhang Tian-Cai; Li Wei-Dong


    We experimentally demonstrate real-time detection of individual cesium atoms by using a high-finesse optical micro-cavity in a strong coupling regime. A cloud of cesium atoms is trapped in a magneto-optical trap positioned at 5 mm above the micro-cavity center. The atoms fall down freely in gravitation after shutting off the magneto-optical trap and pass through the cavity. The cavity transmission is strongly affected by the atoms in the cavity, which enables the micro-cavity to sense the atoms individually. We detect the single atom transits either in the resonance or various detunings. The single atom vacuum-Rabi splitting is directly measured to be Ω = 2π × 23.9 MHz. The average duration of atom-cavity coupling of about 110 μs is obtained according to the probability distribution of the atom transits. (fundamental areas of phenomenology(including applications))

  20. Electrically Injected Polariton Lasing from a GaAs-Based Microcavity under Magnetic Field

    KAUST Repository

    Bhattacharya, Pallab


    Suppression of relaxation bottleneck and subsequent polariton lasing is observed in a GaAs-based microcavity under the application of a magnetic field. The threshold injection current density is 0.32 A/cm2 at 7 Tesla.

  1. Dynamics of polaritons in semiconductor microcavities near instability thresholds

    International Nuclear Information System (INIS)

    He, Peng-Bin


    A theoretical study is presented on the dynamics of polaritons in semiconductor microcavities near parametric instability thresholds. With upward or downward ramp of optical pump, different instability modes emerge in parameter space defined by damping and detuning. According to these modes, stationary short-wave, stationary periodic, oscillatory periodic, and oscillatory uniform parametric instabilities are distinguished. By multiple scale expansion, the dynamics near threshold can be described by a critical mode with a slowly varying amplitude for the last three instabilities. Furthermore, it is found that the evolutions of their amplitudes are governed by real or complex Ginzburg–Landau equations. -- Highlights: ► Phase diagrams for different instability in extended parameter space. ► Different instability modes near thresholds. ► Different envelop equations near thresholds obtained by multi-scale expansion.

  2. Solid state microcavity dye lasers fabricated by nanoimprint lithography

    DEFF Research Database (Denmark)

    Nilsson, Daniel; Nielsen, Theodor; Kristensen, Anders


    We present a solid state polymer microcavity dye laser, fabricated by thermal nanoimprint lithography (NIL) in a dye-doped thermoplast. The thermoplast poly-methylmethacrylate (PMMA) is used due to its high transparency in the visible range and its robustness to laser radiation. The laser dye...... is Rhodamine 6G ClO4. This dye is shown to withstand temperatures up to 240 °C without bleaching, which makes it compatible with the thermal nanoimprint lithography process. The 1.55 µm thick dye-doped PMMA devices are fabricated on a SiO2 substrate, yielding planar waveguiding in the dye-doped PMMA with two...... propagating TE–TM modes. The laser cavity has the lateral shape of a trapezoid, supporting lasing modes by reflection on the vertical cavity walls. The solid polymer dye lasers emit laterally through one of the vertical cavity walls, when pumped optically through the top surface by means of a frequency...

  3. A porous silicon optical microcavity for sensitive bacteria detection

    International Nuclear Information System (INIS)

    Li Sha; Huang Jianfeng; Cai Lintao


    A porous silicon microcavity (PSM) is highly sensitive to subtle interface changes due to its high surface area, capillary condensation ability and a narrow resonance peak (∼10 nm). Based on the well-defined optical properties of a PSM, we successfully fabricated a bacteria detection chip for molecular or subcellular analysis by surface modification using undecylenic acid (UA), and the specific recognition binding of vancomycin to the D-alanyl-D-alanine of bacteria. The red shift of the PSM resonance peak showed a good linear relationship with bacteria concentration ranging from 100 to 1000 bacteria ml -1 at the level of relative standard deviation of 0.994 and detection limit of 20 bacteria ml -1 . The resulting PSM sensors demonstrated high sensitivity, good reproducibility, fast response and low cost for biosensing.

  4. A porous silicon optical microcavity for sensitive bacteria detection (United States)

    Li, Sha; Huang, Jianfeng; Cai, Lintao


    A porous silicon microcavity (PSM) is highly sensitive to subtle interface changes due to its high surface area, capillary condensation ability and a narrow resonance peak (~10 nm). Based on the well-defined optical properties of a PSM, we successfully fabricated a bacteria detection chip for molecular or subcellular analysis by surface modification using undecylenic acid (UA), and the specific recognition binding of vancomycin to the D-alanyl-D-alanine of bacteria. The red shift of the PSM resonance peak showed a good linear relationship with bacteria concentration ranging from 100 to 1000 bacteria ml - 1 at the level of relative standard deviation of 0.994 and detection limit of 20 bacteria ml - 1. The resulting PSM sensors demonstrated high sensitivity, good reproducibility, fast response and low cost for biosensing.

  5. A porous silicon optical microcavity for sensitive bacteria detection

    Energy Technology Data Exchange (ETDEWEB)

    Li Sha; Huang Jianfeng; Cai Lintao, E-mail: [CAS Key Lab of Health Informatics, Shenzhen Key Laboratory of Cancer Nanotechnology, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055 (China)


    A porous silicon microcavity (PSM) is highly sensitive to subtle interface changes due to its high surface area, capillary condensation ability and a narrow resonance peak ({approx}10 nm). Based on the well-defined optical properties of a PSM, we successfully fabricated a bacteria detection chip for molecular or subcellular analysis by surface modification using undecylenic acid (UA), and the specific recognition binding of vancomycin to the D-alanyl-D-alanine of bacteria. The red shift of the PSM resonance peak showed a good linear relationship with bacteria concentration ranging from 100 to 1000 bacteria ml{sup -1} at the level of relative standard deviation of 0.994 and detection limit of 20 bacteria ml{sup -1}. The resulting PSM sensors demonstrated high sensitivity, good reproducibility, fast response and low cost for biosensing.

  6. Advances of Optofluidic Microcavities for Microlasers and Biosensors

    Directory of Open Access Journals (Sweden)

    Zhiqing Feng


    Full Text Available Optofluidic microcavities with high Q factor have made rapid progress in recent years by using various micro-structures. On one hand, they are applied to microfluidic lasers with low excitation thresholds. On the other hand, they inspire the innovation of new biosensing devices with excellent performance. In this article, the recent advances in the microlaser research and the biochemical sensing field will be reviewed. The former will be categorized based on the structures of optical resonant cavities such as the Fabry–Pérot cavity and whispering gallery mode, and the latter will be classified based on the working principles into active sensors and passive sensors. Moreover, the difficulty of single-chip integration and recent endeavors will be briefly discussed.

  7. Alkaline Electrochemical Capacitor and Electrode Fabrication

    National Research Council Canada - National Science Library

    Finello, D


    Highly capacitive (high surface area) electrodes that are electrochemically stable in strong alkaline electrolyte will form the basis for a new generation of electrical and electrochemical energy storage and conversion devices...

  8. Numerical modeling of exciton-polariton Bose-Einstein condensate in a microcavity (United States)

    Voronych, Oksana; Buraczewski, Adam; Matuszewski, Michał; Stobińska, Magdalena


    A novel, optimized numerical method of modeling of an exciton-polariton superfluid in a semiconductor microcavity was proposed. Exciton-polaritons are spin-carrying quasiparticles formed from photons strongly coupled to excitons. They possess unique properties, interesting from the point of view of fundamental research as well as numerous potential applications. However, their numerical modeling is challenging due to the structure of nonlinear differential equations describing their evolution. In this paper, we propose to solve the equations with a modified Runge-Kutta method of 4th order, further optimized for efficient computations. The algorithms were implemented in form of C++ programs fitted for parallel environments and utilizing vector instructions. The programs form the EPCGP suite which has been used for theoretical investigation of exciton-polaritons. Catalogue identifier: AFBQ_v1_0 Program summary URL: Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: BSD-3 No. of lines in distributed program, including test data, etc.: 2157 No. of bytes in distributed program, including test data, etc.: 498994 Distribution format: tar.gz Programming language: C++ with OpenMP extensions (main numerical program), Python (helper scripts). Computer: Modern PC (tested on AMD and Intel processors), HP BL2x220. Operating system: Unix/Linux and Windows. Has the code been vectorized or parallelized?: Yes (OpenMP) RAM: 200 MB for single run Classification: 7, 7.7. Nature of problem: An exciton-polariton superfluid is a novel, interesting physical system allowing investigation of high temperature Bose-Einstein condensation of exciton-polaritons-quasiparticles carrying spin. They have brought a lot of attention due to their unique properties and potential applications in polariton-based optoelectronic integrated circuits. This is an out-of-equilibrium quantum system confined

  9. Tailoring the optical properties of wide-bandgap based microcavities via metal films

    Energy Technology Data Exchange (ETDEWEB)

    Sebald, K., E-mail:; Rahman, SK. S.; Cornelius, M.; Gutowski, J. [Semiconductor Optics, Institute of Solid State Physics, University of Bremen, 28334 Bremen (Germany); Klein, T.; Klembt, S.; Kruse, C.; Hommel, D. [Semiconductor Epitaxy, Institute of Solid State Physics, University of Bremen, 28334 Bremen (Germany)


    We report on the tuning of the optical properties of II-VI-material-based microcavity samples, which is achieved by depositing Ag films on top of the structures. The micro-reflectivity spectra show a spectral shift of the sample resonance dependent on the metal layer thickness. By comparison of the experimental findings with the theoretical calculations applying the transfer matrix method on a metal-dielectric mirror structure, the influence of the metal layer particularly with regard to its partial oxidation was explored. Tamm plasmon modes are created at the interface between an open cavity with three ZnSe quantum wells and a metal layer on top. When tuning the excitonic emission relative to the mode by changing the sample temperature, an anticrossing of the resonances was observed. This is a clear indication that the strong coupling regime has been achieved in that sample configuration yielding a Rabi splitting of 18.5 meV. These results are promising for the realization of polariton-based optical devices with a rather simple sample configuration.

  10. Electrical pumping and tuning of exciton-polaritons in carbon nanotube microcavities (United States)

    Graf, Arko; Held, Martin; Zakharko, Yuriy; Tropf, Laura; Gather, Malte C.; Zaumseil, Jana


    Exciton-polaritons are hybrid light-matter particles that form upon strong coupling of an excitonic transition to a cavity mode. As bosons, polaritons can form condensates with coherent laser-like emission. For organic materials, optically pumped condensation was achieved at room temperature but electrically pumped condensation remains elusive due to insufficient polariton densities. Here we combine the outstanding optical and electronic properties of purified, solution-processed semiconducting (6,5) single-walled carbon nanotubes (SWCNTs) in a microcavity-integrated light-emitting field-effect transistor to realize efficient electrical pumping of exciton-polaritons at room temperature with high current densities (>10 kA cm-2) and tunability in the near-infrared (1,060 nm to 1,530 nm). We demonstrate thermalization of SWCNT polaritons, exciton-polariton pumping rates ~104 times higher than in current organic polariton devices, direct control over the coupling strength (Rabi splitting) via the applied gate voltage, and a tenfold enhancement of polaritonic over excitonic emission. This powerful material-device combination paves the way to carbon-based polariton emitters and possibly lasers.

  11. EDESR of impurity centers in nanostructures inserted in silicon microcavities

    Energy Technology Data Exchange (ETDEWEB)

    Bagraev, Nikolay; Danilovsky, Eduard; Gets, Dmitry; Klyachkin, Leonid; Kudryavtsev, Andrey; Kuzmin, Roman; Malyarenko, Anna [Ioffe Physical-Technical Institute, Polytekhnicheskaya st. 26, 194021 St. Petersburg (Russian Federation); Gehlhoff, Wolfgang [Institut fuer Festkoerperphysik, TU Berlin, 10623 Berlin (Germany); Mashkov, Vladimir; Romanov, Vladimir [State Polytechnical University, 195251 St. Petersburg (Russian Federation)


    We present the first findings of the new electrically detected electron spin resonance technique (EDESR) which reveal single point defects in the ultra-narrow silicon quantum wells (Si-QW) confined by the superconductor {delta}-barriers. This technique allows the ESR identification without the application of the external cavity as well as the high frequency (hf) source and recorder, with measuring the only magnetoresistance caused by the hf emission from the {delta}-barriers in the presence of the microcavity embedded in the Si-QW plane. The new resonant positive magnetoresistance data are interpreted here in terms of the interference transition in the diffusive transport of free holes respectively between the weak antilocalization regime in the range of magnetic fields far from the ESR of a paramagnetic point defect located inside or near the conductive channel and the weak localization regime in the range of magnetic fields corresponding to the ESR of that defect. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  12. Vapor and liquid optical monitoring with sculptured Bragg microcavities (United States)

    Oliva-Ramirez, Manuel; Gil-Rostra, Jorge; López-Santos, Maria Carmen; González-Elipe, Agustín R.; Yubero, Francisco


    Sculptured porous Bragg microcavities (BMs) formed by the successive stacking of columnar SiO2 and TiO2 thin films with a zig-zag columnar microstructure are prepared by glancing angle deposition. These BMs act as wavelength-dependent optical retarders. This optical behavior is attributed to a self-structuration of the stacked layers involving the lateral association of nanocolumns in the direction perpendicular to the main flux of particles during the multilayer film growth, as observed by focused ion beam scanning electron microscopy. The retardance of these optically active BMs can be modulated by dynamic infiltration of their open porosity with vapors, liquids, or solutions with different refractive indices. The tunable birefringence of these nanostructured photonic systems has been successfully simulated with a simple model that assumes that each layer within the BMs stack has uniaxial birefringence. The sculptured BMs have been incorporated as microfluidic chips for optical transduction for label-free vapor and liquid sensing. Several examples of the detection performance of these chips, working either in reflection or transmission configuration, for the optical monitoring of vapor and liquids of different refractive indices and aqueous solutions of glucose flowing through the microfluidic chips are described.

  13. Research on the Band Gap Characteristics of Two-Dimensional Phononic Crystals Microcavity with Local Resonant Structure

    Directory of Open Access Journals (Sweden)

    Mao Liu


    Full Text Available A new two-dimensional locally resonant phononic crystal with microcavity structure is proposed. The acoustic wave band gap characteristics of this new structure are studied using finite element method. At the same time, the corresponding displacement eigenmodes of the band edges of the lowest band gap and the transmission spectrum are calculated. The results proved that phononic crystals with microcavity structure exhibited complete band gaps in low-frequency range. The eigenfrequency of the lower edge of the first gap is lower than no microcavity structure. However, for no microcavity structure type of quadrilateral phononic crystal plate, the second band gap disappeared and the frequency range of the first band gap is relatively narrow. The main reason for appearing low-frequency band gaps is that the proposed phononic crystal introduced the local resonant microcavity structure. This study provides a good support for engineering application such as low-frequency vibration attenuation and noise control.

  14. Silicon on-chip bandpass filters for the multiplexing of high sensitivity photonic crystal microcavity biosensors

    International Nuclear Information System (INIS)

    Yan, Hai; Zou, Yi; Yang, Chun-Ju; Chakravarty, Swapnajit; Wang, Zheng; Tang, Naimei; Chen, Ray T.; Fan, Donglei


    A method for the dense integration of high sensitivity photonic crystal (PC) waveguide based biosensors is proposed and experimentally demonstrated on a silicon platform. By connecting an additional PC waveguide filter to a PC microcavity sensor in series, a transmission passband is created, containing the resonances of the PC microcavity for sensing purpose. With proper engineering of the passband, multiple high sensitivity PC microcavity sensors can be integrated into microarrays and be interrogated simultaneously between a single input and a single output port. The concept was demonstrated with a 2-channel L55 PC biosensor array containing PC waveguide filters. The experiment showed that the sensors on both channels can be monitored simultaneously from a single output spectrum. Less than 3 dB extra loss for the additional PC waveguide filter is observed

  15. Theory and measurement of the soliton self-frequency shift and efficiency in optical microcavities. (United States)

    Yi, Xu; Yang, Qi-Fan; Yang, Ki Youl; Vahala, Kerry


    Dissipative Kerr cavity solitons experience a so-called self-frequency shift (SFS) as a result of Raman interactions. The frequency shift has been observed in several microcavity systems. The Raman process has also been shown numerically to influence the soliton pumping efficiency. Here, a perturbed Lagrangian approach is used to derive simple analytical expressions for the SFS and the soliton efficiency. The predicted dependences of these quantities on soliton pulse width are compared with measurements in a high-Q silica microcavity. The Raman time constant in silica is also inferred. Analytical expressions for the Raman SFS and soliton efficiency greatly simplify the prediction of soliton behavior over a wide range of microcavity platforms.

  16. Optimisation of spontaneous four-wave mixing in a ring microcavity (United States)

    Chuprina, I. N.; An, P. P.; Zubkova, E. G.; Kovalyuk, V. V.; Kalachev, A. A.; Gol'tsman, G. N.


    A theory of spontaneous four-wave mixing in a ring microcavity is developed. The rate of emission of biphotons for pulsed and monochromatic pumping with allowance for the dispersion of group velocities is analytically calculated. In the first case, pulses in the form of an increasing exponential are considered, which are optimal for excitation of an individual resonator mode. The behaviour of the group velocity dispersion as a function of the width and height of the waveguide is studied for a specific case of a ring microcavity made of silicon nitride. The results of the numerical calculation are in good agreement with the experimental data. The ring microcavity is made of two types of waveguides: completely etched and half etched. It is found that the latter allow for better control over the parameters in the manufacturing process, making them more predictable. Presented at the Russian - British Symposium on Quantum Technologies (Moscow, 20 - 23 March 2017)

  17. Silicon on-chip bandpass filters for the multiplexing of high sensitivity photonic crystal microcavity biosensors

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Hai, E-mail:; Zou, Yi; Yang, Chun-Ju [Department of Electrical and Computer Engineering, Microelectronics Research Center, The University of Texas at Austin, 10100 Burnet Rd., Austin, Texas 78758 (United States); Chakravarty, Swapnajit, E-mail: [Omega Optics, Inc., 8500 Shoal Creek Blvd., Austin, Texas 78757 (United States); Wang, Zheng [Department of Electrical and Computer Engineering, Microelectronics Research Center, The University of Texas at Austin, 10100 Burnet Rd., Austin, Texas 78758 (United States); Materials Science and Engineering Program, Texas Materials Institute, The University of Texas at Austin, Austin, Texas 78712 (United States); Tang, Naimei; Chen, Ray T., E-mail: [Department of Electrical and Computer Engineering, Microelectronics Research Center, The University of Texas at Austin, 10100 Burnet Rd., Austin, Texas 78758 (United States); Omega Optics, Inc., 8500 Shoal Creek Blvd., Austin, Texas 78757 (United States); Fan, Donglei [Materials Science and Engineering Program, Texas Materials Institute, The University of Texas at Austin, Austin, Texas 78712 (United States); Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712 (United States)


    A method for the dense integration of high sensitivity photonic crystal (PC) waveguide based biosensors is proposed and experimentally demonstrated on a silicon platform. By connecting an additional PC waveguide filter to a PC microcavity sensor in series, a transmission passband is created, containing the resonances of the PC microcavity for sensing purpose. With proper engineering of the passband, multiple high sensitivity PC microcavity sensors can be integrated into microarrays and be interrogated simultaneously between a single input and a single output port. The concept was demonstrated with a 2-channel L55 PC biosensor array containing PC waveguide filters. The experiment showed that the sensors on both channels can be monitored simultaneously from a single output spectrum. Less than 3 dB extra loss for the additional PC waveguide filter is observed.

  18. Hydrostatic pressure sensor based on micro-cavities developed by the catastrophic fuse effect (United States)

    Domingues, M. F.; Paixão, T.; Mesquita, E.; Alberto, N.; Antunes, P.; Varum, H.; André, P. S.


    In this work, an optical fiber hydrostatic pressure sensor based in Fabry-Perot micro-cavities is presented. These micro structures were generated by the recycling of optical fiber previously damaged by the fiber fuse effect, resulting in a cost effective solution when compared with the traditional methods used to produce similar micro-cavities. The developed sensor was tested for pressures ranging from 20.0 to 190.0 cmH2O and a sensitivity of 53.7 +/- 2.6 pm/cmH2O for hydrostatic pressures below to 100 cmH2O was achieved.

  19. Black phosphorus-based one-dimensional photonic crystals and microcavities. (United States)

    Kriegel, Ilka; Toffanin, Stefano; Scotognella, Francesco


    The latest achievements in the fabrication of thin layers of black phosphorus (BP), toward the technological breakthrough of a phosphorene atomically thin layer, are paving the way for their use in electronics, optics, and optoelectronics. In this work, we have simulated the optical properties of one-dimensional photonic structures, i.e., photonic crystals and microcavities, in which few-layer BP is one of the components. The insertion of the 5-nm black phosphorous layers leads to a photonic band gap in the photonic crystals and a cavity mode in the microcavity that is interesting for light manipulation and emission enhancement.

  20. Quantum correlation control for two semiconductor microcavities connected by an optical fiber (United States)

    Mohamed, A.-B. A.; Eleuch, H.


    We explore the quantum correlations for two coupled quantum wells. Each quantum well is inside a semiconductor microcavity. The two cavities are connected by an optical fiber. The study of quantum correlations, namely the geometric quantum discord, measurement-induced non-locality and negativity, reveals sudden death and sudden birth phenomena. These effects depend not only on the initial states, coupling strengths of the cavity-fiber and cavity-exciton constants, but also on the dissipation rates of the semiconductor microcavities. We show that the coupling constants control the quantum correlations.

  1. An All Fiber Intrinsic Fabry-Perot Interferometer Based on an Air-Microcavity

    Directory of Open Access Journals (Sweden)

    Ruth I. Mata-Chávez


    Full Text Available In this work an Intrinsic Fabry-Perot Interferometer (IFPI based on an air-microcavity is presented. Here the air microcavity, with silica walls, is formed at a segment of a hollow core photonic crystal fiber (HCPCF, which is fusion spliced with a single mode fiber (SMF. Moreover, the spectral response of the IFPI is experimentally characterized and some results are provided. Finally, the viability to use the IFPI to implement a simple, compact size, and low cost refractive index sensor is briefly analyzed.

  2. Detecting single DNA molecule interactions with optical microcavities (Presentation Recording) (United States)

    Vollmer, Frank


    as the detection of less than 1 kDa intercalating small molecules[1]. [1] M. D. Baaske, M. R. Foreman, and F. Vollmer, "Single molecule nucleic acid interactions monitored on a label-free microcavity biosensing platform," Nature Nanotechnology, vol. 9, pp. 933-939, 2014. [2] Y. Wu, D. Y. Zhang, P. Yin, and F. Vollmer, "Ultraspecific and Highly Sensitive Nucleic Acid Detection by Integrating a DNA Catalytic Network with a Label-Free Microcavity," Small, vol. 10, pp. 2067-2076, 2014. [3] M. R. Foreman, W.-L. Jin, and F. Vollmer, "Optimizing Detection Limits in Whispering Gallery Mode Biosensing," Optics Express, vol. 22, pp. 5491-5511, 2014. [4] M. A. Santiago-Cordoba, S. V. Boriskina, F. Vollmer, and M. C. Demirel, "Nanoparticle-based protein detection by optical shift of a resonant microcavity," Applied Physics Letters, vol. 99, Aug 2011. [5] M. R. Foreman and F. Vollmer, "Theory of resonance shifts of whispering gallery modes by arbitrary plasmonic nanoparticles," New Journal of Physics, vol. 15, p. 083006, Aug 2013. [6] M. R. Foreman and F. Vollmer "Level repulsion in hybrid photonic-plasmonic microresonators for enhanced biodetection" Phys. Rev. A 88, 023831 (2013).

  3. Photoluminescence eigenmodes in the ZnO semiconductor microcavity on the Ag/Si substrate

    Czech Academy of Sciences Publication Activity Database

    Luo, X.; Wang, J.; Mao, H.; Remeš, Zdeněk; Král, Karel


    Roč. 112, č. 4 (2013), s. 821-825 ISSN 0947-8396 R&D Projects: GA MŠk LH12186 Institutional support: RVO:68378271 Keywords : ZnO * photoluminescence * microcavity Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.694, year: 2013

  4. Cavity-polariton interaction mediated by coherent acoustic phonons in semiconductor microcavities

    DEFF Research Database (Denmark)

    de Lima, Mauricio; Hey, Rudolf; Santos, Paul

    (SAWs) in a GaAs QW embedded in a (Al,Ga)As/AlAs microcavity. The periodic modulation introduced by the phonons folds the cavity-polariton dispersion within a mini-Brillouin zone (MBZ) defined by the phonon wave vector ($k_\\mathrm{SAW}$). The appearance of well-defined mini-gaps at the edge of the MBZ...

  5. Optical theorem helps understand thresholds of lasing in microcavities with active regions

    Czech Academy of Sciences Publication Activity Database

    Smotrova, E. I.; Byelobrov, V.; Benson, T. M.; Čtyroký, Jiří; Sauleau, R.; Nosich, A. I.


    Roč. 47, č. 1 (2011), s. 20-30 ISSN 0018-9197 Institutional research plan: CEZ:AV0Z20670512 Keywords : Eigenvalue problem * lasing threshold * microcavity laser Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.879, year: 2011

  6. All-optical tunable buffering with coupled ultra-high Q whispering gallery mode microcavities. (United States)

    Yoshiki, Wataru; Honda, Yoshihiro; Tetsumoto, Tomohiro; Furusawa, Kentaro; Sekine, Norihiko; Tanabe, Takasumi


    All-optical tunable buffering was recently achieved on a chip by using dynamically tuned coupled mode induced transparency, which is an optical analogue of electromagnetically induced transparency. However, the small Q s of about 10 5 used in those systems were limiting the maximum buffering time to a few hundred ps. Although employing an ultra-high Q whispering gallery mode (WGM) microcavity can significantly improve the maximum buffering time, the dynamic tuning of the WGM has remained challenging because thermo-optic and pressure tunings, which are widely used for WGM microcavities, have a very slow response. Here we demonstrate all-optical tunable buffering utilizing coupled ultra-high Q WGM cavities and the Kerr effect. The Kerr effect can change the refractive index instantaneously, and this allowed us to tune the WGM cavity very quickly. In addition, from among the various WGM cavities we employed a silica toroid microcavity for our experiments because it has an ultra-high Q factor (>2 × 10 7 ) and a small mode volume, and can be fabricated on a chip. Use of the Kerr effect and the silica toroid microcavity enabled us to observe an on-chip all-optical tunable buffering operation and achieve a maximum buffering time of 20 ns.

  7. Multiple kinds of emission modes in semiconductor microcavity coupled with plasmon

    Czech Academy of Sciences Publication Activity Database

    Du, L.; Mao, H.; Luo, X.; Wang, J.; Remeš, Zdeněk


    Roč. 434, č. 1 (2014), s. 74-77 ISSN 0921-4526 R&D Projects: GA MŠk LH12186 Institutional support: RVO:68378271 Keywords : plasmon * exciton * polariton * microcavity * ZnO * effective refractive index Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.319, year: 2014

  8. Anodes for alkaline electrolysis (United States)

    Soloveichik, Grigorii Lev [Latham, NY


    A method of making an anode for alkaline electrolysis cells includes adsorption of precursor material on a carbonaceous material, conversion of the precursor material to hydroxide form and conversion of precursor material from hydroxide form to oxy-hydroxide form within the alkaline electrolysis cell.

  9. Alkaline "Permanent" Paper. (United States)

    Pacey, Antony


    Discussion of paper manufacturing processes and their effects on library materials focuses on the promotion of alkaline "permanent" paper, with less acid, by Canadian library preservation specialists. Standards for paper acidity are explained; advantages of alkaline paper are described, including decreased manufacturing costs; and…

  10. Progress Toward Single-Photon-Level Nonlinear Optics in Crystalline Microcavities (United States)

    Kowligy, Abijith S.

    Over the last two decades, the emergence of quantum information science has uncovered many practical applications in areas such as communications, imaging, and sensing where harnessing quantum features of Nature provides tremendous benefits over existing methods exploiting classical physical phenomena. In this effort, one of the frontiers of research has been to identify and utilize quantum phenomena that are not susceptible to environmental and parasitic noise processes. Quantum photonics has been at the forefront of these studies because it allows room-temperature access to its inherently quantum-mechanical features, and allows leveraging the mature telecommunication industry. Accompanying the weak environmental influence, however, are also weak optical nonlinearities. Efficient nonlinear optical interactions are indispensible for many of the existing protocols for quantum optical computation and communication, e.g. high-fidelity entangling quantum logic gates rely on large nonlinear responses at the one- or few-photon-level. While this has been addressed to a great extent by interfacing photons with single quantum emitters and cold atomic gases, scalability has remained elusive. In this work, we identify the macroscopic second-order nonlinear polarization as a robust platform to address this challenge, and utilize the recent advances in the burgeoning field of optical microcavities to enhance this nonlinear response. In particular, we show theoretically that by using the quantum Zeno effect, low-noise, single-photon-level optical nonlinearities can be realized in lithium niobate whispering-gallery-mode microcavities, and present experimental progress toward this goal. Using the measured strength of the second-order nonlinear response in lithium niobate, we modeled the nonlinear system in the strong coupling regime using the Schrodinger picture framework and theoretically demonstrated that the single-photon-level operation can be observed for cavity lifetimes in

  11. The role of group index engineering in series-connected photonic crystal microcavities for high density sensor microarrays

    International Nuclear Information System (INIS)

    Zou, Yi; Zhu, Liang; Chen, Ray T.; Chakravarty, Swapnajit


    We experimentally demonstrate an efficient and robust method for series connection of photonic crystal microcavities that are coupled to photonic crystal waveguides in the slow light transmission regime. We demonstrate that group index taper engineering provides excellent optical impedance matching between the input and output strip waveguides and the photonic crystal waveguide, a nearly flat transmission over the entire guided mode spectrum and clear multi-resonance peaks corresponding to individual microcavities that are connected in series. Series connected photonic crystal microcavities are further multiplexed in parallel using cascaded multimode interference power splitters to generate a high density silicon nanophotonic microarray comprising 64 photonic crystal microcavity sensors, all of which are interrogated simultaneously at the same instant of time

  12. Tubular oxide microcavity with high-index-contrast walls: Mie scattering theory and 3D confinement of resonant modes. (United States)

    Wang, Jiao; Zhan, Tianrong; Huang, Gaoshan; Cui, Xugao; Hu, Xinhua; Mei, Yongfeng


    Tubular oxide optical microcavities with thin walls (Mie scattering theory. Novel material design and superior optical resonant properties in such self-rolled micro-tubular cavities promise many potential applications e.g. in optofluidic sensing and lasing.

  13. Graphene-supported plasmonic whispering-gallery mode in a metal-coated microcavity for sensing application with ultrahigh sensitivity (United States)

    Fan, Huibo; Xia, Changquan; Fan, Li; Wang, Lichun; Shen, Mingya


    We propose and numerically investigate the plasmonic whispering-gallery mode (WGM) with high-quality (Q) factor (as high as 285) and ultra-small mode volume (as low as 0 . 04 μm3) in the hybrid plasmonic microcavity with a sandwiched and electrically controlled graphene. The theoretical results present that the resonant wavelength of hybrid plasmonic microcavity dramatically changes and the corresponding intrinsic loss exhibits a distinct peak by electrically adjusting the permittivity of graphene around the epsilon-near-zero (ENZ) point. The influence of graphene with different layers on the characteristic of hybrid plasmonic microcavity is also analyzed. As a potential application, the plasmonic WGM microcavity with the sandwiched graphene could be applied for a refractometer with the sensitivity of higher than 1000 nm per refraction index unit (nm/RIU), and large figure of merit. The sensitivity can also be tuned by the electrically controlled graphene.

  14. Alkaline battery operational methodology (United States)

    Sholklapper, Tal; Gallaway, Joshua; Steingart, Daniel; Ingale, Nilesh; Nyce, Michael


    Methods of using specific operational charge and discharge parameters to extend the life of alkaline batteries are disclosed. The methods can be used with any commercial primary or secondary alkaline battery, as well as with newer alkaline battery designs, including batteries with flowing electrolyte. The methods include cycling batteries within a narrow operating voltage window, with minimum and maximum cut-off voltages that are set based on battery characteristics and environmental conditions. The narrow voltage window decreases available capacity but allows the batteries to be cycled for hundreds or thousands of times.

  15. Photonic transistor and router using a single quantum-dot-confined spin in a single-sided optical microcavity. (United States)

    Hu, C Y


    The future Internet is very likely the mixture of all-optical Internet with low power consumption and quantum Internet with absolute security guaranteed by the laws of quantum mechanics. Photons would be used for processing, routing and com-munication of data, and photonic transistor using a weak light to control a strong light is the core component as an optical analogue to the electronic transistor that forms the basis of modern electronics. In sharp contrast to previous all-optical tran-sistors which are all based on optical nonlinearities, here I introduce a novel design for a high-gain and high-speed (up to terahertz) photonic transistor and its counterpart in the quantum limit, i.e., single-photon transistor based on a linear optical effect: giant Faraday rotation induced by a single electronic spin in a single-sided optical microcavity. A single-photon or classical optical pulse as the gate sets the spin state via projective measurement and controls the polarization of a strong light to open/block the photonic channel. Due to the duality as quantum gate for quantum information processing and transistor for optical information processing, this versatile spin-cavity quantum transistor provides a solid-state platform ideal for all-optical networks and quantum networks.

  16. Optical microcavities based on surface modes in two-dimensional photonic crystals and silicon-on-insulator photonic crystals

    DEFF Research Database (Denmark)

    Xiao, Sanshui; Qiu, M.


    Surface-mode optical microcavities based on two-dimensional photonic crystals and silicon-on-insulator photonic crystals are studied. We demonstrate that a high-quality-factor microcavity can be easily realized in these structures. With an increasing of the cavity length, the quality factor...... is gradually enhanced and the resonant frequency converges to that of the corresponding surface mode in the photonic crystals. These structures have potential applications such as sensing....

  17. Uranium in alkaline rocks

    International Nuclear Information System (INIS)

    Murphy, M.; Wollenberg, H.; Strisower, B.; Bowman, H.; Flexser, S.; Carmichael, I.


    Geologic and geochemical criteria were developed for the occurrence of economic uranium deposits in alkaline igneous rocks. A literature search, a limited chemical analytical program, and visits to three prominent alkaline-rock localities (Ilimaussaq, Greenland; Pocos de Caldas, Brazil; and Powderhorn, Colorado) were made to establish criteria to determine if a site had some uranium resource potential. From the literature, four alkaline-intrusive occurrences of differing character were identified as type-localities for uranium mineralization, and the important aspects of these localities were described. These characteristics were used to categorize and evaluate U.S. occurrences. The literature search disclosed 69 U.S. sites, encompassing nepheline syenite, alkaline granite, and carbonatite. It was possible to compare two-thirds of these sites to the type localities. A ranking system identified ten of the sites as most likely to have uranium resource potential

  18. Uranium in alkaline rocks

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, M.; Wollenberg, H.; Strisower, B.; Bowman, H.; Flexser, S.; Carmichael, I.


    Geologic and geochemical criteria were developed for the occurrence of economic uranium deposits in alkaline igneous rocks. A literature search, a limited chemical analytical program, and visits to three prominent alkaline-rock localities (Ilimaussaq, Greenland; Pocos de Caldas, Brazil; and Powderhorn, Colorado) were made to establish criteria to determine if a site had some uranium resource potential. From the literature, four alkaline-intrusive occurrences of differing character were identified as type-localities for uranium mineralization, and the important aspects of these localities were described. These characteristics were used to categorize and evaluate U.S. occurrences. The literature search disclosed 69 U.S. sites, encompassing nepheline syenite, alkaline granite, and carbonatite. It was possible to compare two-thirds of these sites to the type localities. A ranking system identified ten of the sites as most likely to have uranium resource potential.

  19. Characterization and quantification of biochar alkalinity. (United States)

    Fidel, Rivka B; Laird, David A; Thompson, Michael L; Lawrinenko, Michael


    Lack of knowledge regarding the nature of biochar alkalis has hindered understanding of pH-sensitive biochar-soil interactions. Here we investigate the nature of biochar alkalinity and present a cohesive suite of methods for its quantification. Biochars produced from cellulose, corn stover and wood feedstocks had significant low-pK a organic structural (0.03-0.34 meq g -1 ), other organic (0-0.92 meq g -1 ), carbonate (0.02-1.5 meq g -1 ), and other inorganic (0-0.26 meq g -1 ) alkalinities. All four categories of biochar alkalinity contributed to total biochar alkalinity and are therefore relevant to pH-sensitive soil processes. Total biochar alkalinity was strongly correlated with base cation concentration, but biochar alkalinity was not a simple function of elemental composition, soluble ash, fixed carbon, or volatile matter content. More research is needed to characterize soluble biochar alkalis other than carbonates and to establish predictive relationships among biochar production parameters and the composition of biochar alkalis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Numerical Investigation on Micro-Cavity Effect of Top-Emitting Organic Light Emitting Diode. (United States)

    Lee, Hyeongi; Hwang, Youngwook; Won, Taeyoung


    In this paper, we report our numerical investigation on the top-emitting OLED (Organic Light Emitting Diodes) with micro-cavity. Our numerical model includes an ensemble of radiating dipole antennas for light emission as well as Poisson Equation for carrier injection and transportation. We formulated a set of differential equations by the Finite Element Method. Our simulation revealed that the recombination rate is affected by the thickness of each layer comprising the OLED structure and the amount of emission is determined by the total thickness of the OLED structure due to micro-cavity effect which is observed in between the total reflection layer and the half reflection layer. Our numerical solver enables us to optimize the OLED structure and thereby improve the external quantum efficiency.

  1. Investigation on the extended range of absorbing film for a microcavity enhanced graphene photodetector (United States)

    Liu, Hai-Xia; Liu, Kai-Ming; Niu, Yan-Xiong


    Microcavity is the preferred graphene-based photodetector structure for its perfect feature of narrow spectral width and absorption enhancement, thus its application sheds light on ultra-fast detection in optic telecommunication and sensing fields. Due to an extremely thin film of graphene, the present study naturally deems it essential to locate the graphene in the exact position of resonant peak intensity. Here an extended graphene position margin in asymmetric planar microcavity with absorption higher than 97.35% was demonstrated. The shift of the centre wavelength caused by graphene was revealed to be non-negligible for telecommunication applications and graphene applied devices. The maximum shift beyond the designed wavelength of 1550 nm has reached 1.07 nm in the λ/2 cavity, which may have severe impact on the DWDM system. Our theoretical investigation amplifies the absorption features and the parasitical spectrum alterations of a designed photodetector with graphene.

  2. Voltage-controlled colour-tunable microcavity OLEDs with enhanced colour purity

    International Nuclear Information System (INIS)

    Choy, Wallace C H; Niu, J H; Li, W L; Chui, P C


    The emission spectrum of single-unit voltage-controlled colour-tunable organic light emitting devices (OLEDs) has been theoretically and experimentally studied. Our results show that by introducing the microcavity structure, the colour purity of not only the destination colour but also the colour-tunable route can be enhanced, while colour purity is still an issue in typical single-unit voltage-controlled colour-tunable OLEDs. With the consideration of the periodical cycling of resonant wavelength and absorption loss of the metal electrodes, the appropriate change in the thickness of the microcavity structure has been utilized to achieve voltage-controlled red-to-green and red-to-blue colour-tunable OLEDs without adding dyes or other organic materials to the OLEDs

  3. Microcavity-coupled fiber Bragg grating with tunable reflection spectra and speed of light. (United States)

    Chen, Lei; Han, Ya; Liu, Qian; Liu, Yan-Ge; Zhang, Weigang; Chou, Keng C


    After a fiber Bragg grating (FBG) is fabricated, the reflection spectrum of the FBG is generally not tunable without mechanical deformation or temperature adjustment. Here we present a microcavity-coupled FBG with both a tunable reflection lineshape and dispersion using electromagnetically induced transparency. The Fano interference of light in the FBG and the microcavity allows for dramatic modification of the reflection spectrum. The phase of the reflected spectrum is continuously tunable between 0 and 2π to produce various Fano lineshapes. The dispersion of the output light is adjustable from normal dispersion to abnormal dispersion, consequently providing an adjustable speed of light. Additionally, it allows the FBG to switch from a notch filter to a bandpass filter at the resonant wavelength, which is not possible in a conventional uniform FBG.

  4. Transition between Kerr comb and stimulated Raman comb in a silica whispering gallery mode microcavity (United States)

    Fujii, Shun; Kato, Takumi; Suzuki, Ryo; Hori, Atsuhiro; Tanabe, Takasumi


    We theoretically and experimentally investigated the transition between modulation instability and Raman gain in a small silica microcavity with a large free-spectral range (FSR), which reveals that we can selectively switch from a four-wave mixing dominant state to a stimulated Raman scattering dominant state. Both the theoretical analysis and the experiment show that a Raman-dominant region is present between transitions of Kerr combs with different free-spectral range spacings. We can obtain a stable Kerr comb and a stable Raman state selectively by changing the driving power, coupling between the cavity and the waveguide, and laser detuning. Such a controllable transition is achieved thanks to the presence of gain competition between modulation instability and Raman gain in silica whispering gallery mode microcavities.

  5. Influence of Carrier Cooling on the Emission Dynamics of Semiconductor Microcavity Lasers (United States)

    Hilpert, M.; Hofmann, M.; Ellmers, C.; Oestreich, M.; Schneider, H. C.; Jahnke, F.; Koch, S. W.; Rühle, W. W.; Wolf, H. D.; Bernklau, D.; Riechert, H.


    We investigate the influence of carrier relaxation on the emission dynamics of a semiconductor microcavity laser. The structure is optically excited with energies of 1.477 down to 1.346 eV (resonant excitation). The stimulated emission dynamics clearly becomes faster for decreasing excitation energy and the influence of the light hole on the emission dynamics is demonstrated. Theoretical calculations reproduce the results only if the nonequilibrium carrier dynamics is treated on the basis of a microscopic model.

  6. Electrically-detected magnetic resonance in semiconductor nanostructures inserted in microcavities

    Energy Technology Data Exchange (ETDEWEB)

    Bagraev, Nikolay; Danilovskii, Eduard; Gets, Dmitrii; Klyachkin, Leonid; Kudryavtsev, Andrey; Kuzmin, Roman; Malyarenko, Anna [Ioffe Physical Technical Institute, Polytekhnicheskaya 26, 194021 St. Petersburg (Russian Federation); Gehlhoff, Wolfgang [Technische Universitaet Berlin, D-10623, Berlin (Germany); Mashkov, Vladimir; Romanov, Vladimir [Petersburg State Polytechnical University, Polytekhnicheskaya 29, 195251 St. Petersburg (Russian Federation)


    We present the first findings of the new electrically-detected electron spin resonance technique (EDESR), which reveal the point defects in the ultra-narrow silicon quantum wells (Si-QW) confined by the superconductor δ-barriers. This technique allows the ESR identification without application of an external cavity, as well as a high frequency source and recorder, and with measuring the only response of the magnetoresistance caused by the microcavities embedded in the Si-QW plane.

  7. Polariton solitons and nonlinear localized states in a one-dimensional semiconductor microcavity (United States)

    Chen, Ting-Wei; Cheng, Szu-Cheng


    This paper presents numerical studies of cavity polariton solitons (CPSs) in a resonantly pumped semiconductor microcavity with an imbedded spatial defect. In the bistable regime of the well-known homogeneous polariton condensate, with proper incident wave vector and pump strength, bright and/or dark cavity solitons can be found in the presence of a spatially confined potential. The minimum pump strength required to observe the CPSs or nonlinear localized states in this parametric pump scheme is therefore reported.

  8. Alkaline phosphatase: an overview. (United States)

    Sharma, Ujjawal; Pal, Deeksha; Prasad, Rajendra


    Alkaline phosphatase (ALP; E.C.3.I.3.1.) is an ubiquitous membrane-bound glycoprotein that catalyzes the hydrolysis of phosphate monoesters at basic pH values. Alkaline phosphatase is divided into four isozymes depending upon the site of tissue expression that are Intestinal ALP, Placental ALP, Germ cell ALP and tissue nonspecific alkaline phosphatase or liver/bone/kidney (L/B/K) ALP. The intestinal and placental ALP loci are located near the end of long arm of chromosome 2 and L/B/K ALP is located near the end of the short arm of chromosome 1. Although ALPs are present in many mammalian tissues and have been studied for the last several years still little is known about them. The bone isoenzyme may be involved in mammalian bone calcification and the intestinal isoenzyme is thought to play a role in the transport of phosphate into epithelial cells of the intestine. In this review, we tried to provide an overview about the various forms, structure and functions of alkaline phosphatase with special focus on liver/bone/kidney alkaline phosphatase.

  9. High quality factor Er-doped Fabry-Perot microcavities by sol-gel processing

    Energy Technology Data Exchange (ETDEWEB)

    Li Yigang; Fortes, Luis M; Almeida, Rui M [Departamento de Engenharia de Materiais/ICEMS, Instituto Superior Tecnico/TULisbon, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Chiappini, Andrea; Ferrari, Maurizio, E-mail:, E-mail: rui.almeida@ist.utl.p [CNR-IFN, Istituto di Fotonica e Nanotecnologie, CSMFO Lab., Via alla Cascata 56/C, Povo, 38123 Trento (Italy)


    An optimized sol-gel process was developed to fabricate 1D photonic bandgap structures. Several erbium-doped Fabry-Perot microcavities were prepared and characterized. The thickest sample contained two Bragg mirrors, each having 12 distributed Bragg reflector periods of alternating silicate glass and titania layers. The total thickness of this sample reached {approx}12 {mu}m. The Er{sup 3+} photoluminescence spectra at 1.5 {mu}m were measured for the microcavities. A quality factor of 250 and an Er{sup 3+} photoluminescence enhancement of 96 times at 1.5 {mu}m have been reached. The sol-gel processing details, the crystallization of the titania films and the refractive index of the deposited materials are discussed in detail. The simulated optical spectra of the microcavities were found to agree well with the actually measured curves. These results demonstrate that the present sol-gel processing technique is of potential interest for low cost fabrication of 1D photonic bandgap devices.

  10. Whispering gallery mode coulometry of the nanoparticle-microcavity interaction in aqueous solution (United States)

    Lopez, Jehovani R.; Treasurer, Eshan; Snyder, Kaitlynn M.; Keng, David; Arnold, Stephen


    Charge influences the binding of virus and other nano-particles to microcavity bio-sensors, although surprisingly there have been no reports of the determination of either cavity charge density σw or nanoparticle charge qp using these sensors. In this letter, we experimentally demonstrate an approach for the determination of both. We use an opto-mechanical Whispering Gallery Mode (WGM) Carousel trap to extract the electrostatic interaction energy versus separation s between the cavity surface and a nanoparticle from WGM frequency fluctuations induced by the orbiting particle. Next, we fit this interaction energy to linearized wall-colloid theory (Debye-Hückel theory) for a particle whose charge is known and determine σw. With this microcavity charge density in hand, a larger particle having unknown charge and orbiting the same microcavity has its charge measured from its associated electrostatic interaction energy. This charge is found to be smaller by 10% when compared to results from independent zeta potential measurements and outside of one standard deviation. However, non-linear Gouy-Chapman theory when applied to our measured data arrives at a charge that overlaps zeta potential measurements. Our method is non-destructive, enabling the same particle to be passed on for further characterization.

  11. Advanced alkaline water electrolysis

    International Nuclear Information System (INIS)

    Marini, Stefania; Salvi, Paolo; Nelli, Paolo; Pesenti, Rachele; Villa, Marco; Berrettoni, Mario; Zangari, Giovanni; Kiros, Yohannes


    A short review on the fundamental and technological issues relevant to water electrolysis in alkaline and proton exchange membrane (PEM) devices is given. Due to price and limited availability of the platinum group metal (PGM) catalysts they currently employ, PEM electrolyzers have scant possibilities of being employed in large-scale hydrogen production. The importance and recent advancements in the development of catalysts without PGMs are poised to benefit more the field of alkaline electrolysis rather than that of PEM devices. This paper presents our original data which demonstrate that an advanced alkaline electrolyzer with performances rivaling those of PEM electrolyzers can be made without PGM and with catalysts of high stability and durability. Studies on the advantages/limitations of electrolyzers with different architectures do show how a judicious application of pressure differentials in a recirculating electrolyte scheme helps reduce mass transport limitations, increasing efficiency and power density.

  12. [Advances of alkaline amylase production and applications]. (United States)

    Yang, Haiquan; Liu, Long; Li, Jianghua; Du, Guocheng; Chen, Jian


    Alkaline amylase is one of alkaline enzymes with optimum pH in the alkaline range, and it could keep stability and efficiently hydrolyze starch under alkaline conditions. Alkaline amylase finds wide applications in textile, detergent, pharmaceutical, food and other fields. Alkaline amylases could be produced by alkaliphilic microorganisms. In this work, the advances of alkaline amylase production and applications were reviewed.

  13. Viscosity of Molten Alkaline-Earth Fluorides (United States)

    Takeda, Osamu; Hoshino, Yosuke; Anbo, Yusuke; Yanagase, Kei-ichi; Aono, Masahiro; Sato, Yuzuru


    The viscosities of molten alkaline-earth fluorides were measured using the oscillating crucible method, which is especially suitable for measuring molten salts with low viscosity. The results showed a good Arrhenius linearity over a wide temperature range. The measured viscosities and activation energies increased in the following order: . Judging by the charge density, the viscosity of alkaline-earth fluorides should increase from molten to . However, the results indicate a different tendency, which may be explained by a Coulomb force that is very strong. The low viscosity of can be attributed to a decreased cohesive force, due to a partial loss of the Coulomb force caused by a higher charge density of the material. The viscosities were also compared to those of molten alkali fluorides and alkaline-earth chlorides. The viscosities of molten alkaline-earth fluorides were higher than those of molten alkali fluorides and alkaline-earth chlorides. The viscosity determined in this study was compared to literature values and showed a reasonable value in the relatively low-viscosity region.

  14. Cost-effective optical fiber pressure sensor based on intrinsic Fabry-Perot interferometric micro-cavities (United States)

    Domingues, M. Fátima; Rodriguez, Camilo A.; Martins, Joana; Tavares, Cátia; Marques, Carlos; Alberto, Nélia; André, Paulo; Antunes, Paulo


    In this work, a cost-effective procedure to manufacture optical fiber pressure sensors is presented. This has a high relevance for integration in robotic exoskeletons or for gait plantar pressure monitoring within the physical rehabilitation scenarios, among other applications. The sensing elements are based on Fabry-Perot interferometric (FPI) micro-cavities, created from the recycling of optical fibers previously destroyed by the catastrophic fuse effect. To produce the pressure sensors, the fiber containing the FPI micro-cavities was embedded in an epoxy resin cylinder used as pressure transducer and responsible to transfer the pressure applied on its surface to the optical fiber containing the FPI micro-cavity. Before the embedding process, some FPI sensors were also characterized to strain variations. After that, the effect of the encapsulation of the FPI structure into the resin was assessed, from which a slight decrease on the FPI interferogram fringes visibility was verified, indicating a small increase in the micro-cavity length. Up on the sensors characterization, a linear dependence of the wavelength shift with the induced pressure was obtained, which leads to a maximum sensitivity of 59.39 ± 1.7 pm/kPa. Moreover, direct dependence of the pressure sensitivity with the micro-cavity volume and length was found.

  15. On the origin of nonclassical light generation upon resonant excitation of a GaAs semiconductor microcavity (United States)

    Demenev, A. A.; Domaretskii, D. R.; Parakhonskii, A. L.; Lebedev, M. V.


    It was shown in JETP Lett. 102, 508 (2015) that the intensity correlation function of the emission from a high-quality-factor semiconductor microcavity under resonant optical pumping exhibits an oscillatory behavior with an unexpectedly long oscillation period and a long decay time, which fall in the nanosecond range. A further investigation demonstrates that the origin of these oscillations is not related to the weak Rabi interaction between long-lived localized exciton states in the quantum well and the electromagnetic field of the microcavity mode. It proves that the semiconductor microcavity plays a secondary role in the observation of nonclassical light: it provides the spectral selection of the modes of the pump laser. We believe that intrinsic instabilities lead to the chaotic excitation of spiking in the laser modes under a constant operating current.

  16. Correlated-photon-pair emission from a cw-pumped Fabry-Perot microcavity (United States)

    Langerfeld, Thorsten F.; Meyer, Hendrik M.; Köhl, Michael


    We study a dispersion-compensated high-finesse optical Fabry-Perot microcavity under high-intensity cw pumping. The Kerr nonlinearity in the optical coatings causes a spontaneous four-wave mixing process, which leads to the emission of time-correlated photon pairs. The photon frequencies are shifted by ±1 free spectral range relative to the pump frequency. This setup allows for constructing a photon-pair source with precisely adjustable frequency difference between the emitted photons, which may have applications in quantum communication.

  17. Dye Giant Absorption and Light Confinement Effects in Porous Bragg Microcavities

    DEFF Research Database (Denmark)

    Oliva-Ramírez, Manuel; Gil-Rostra, Jorge; Simonsen, Adam C.


    This work presents a simple experimental procedure to probe light confinement effects in photonic structures. Two types of porous 1D Bragg microcavities with two resonant peaks in the reflection gap were prepared by physical vapor deposition at oblique angle configurations and then infiltrated...... with dye solutions of increasing concentrations. The unusual position shift and intensity drop of the transmitted resonant peak observed when it was scanned through the dye absorption band have been accounted for by the effect of the light trapped at their optical defect layer. An experimentally observed...... and simple methodology to experimentally assess light trapping effects in porous photonic structures....

  18. Observation of long-lived polariton states in semiconductor microcavities across the parametric threshold. (United States)

    Ballarini, D; Sanvitto, D; Amo, A; Viña, L; Wouters, M; Carusotto, I; Lemaitre, A; Bloch, J


    The excitation spectrum around the pump-only stationary state of a polariton optical parametric oscillator in semiconductor microcavities is investigated by time-resolved photoluminescence. The response to a weak pulsed perturbation in the vicinity of the idler mode is directly related to the lifetime of the elementary excitations. A dramatic increase of the lifetime is observed for a pump intensity approaching and exceeding the optical parametric oscillator threshold. The observations can be explained in terms of a critical slowing down of the dynamics upon approaching the threshold and the following appearance of a soft Goldstone mode in the spectrum.

  19. Oxide-apertured microcavity single-photon-emitting diodes-simultaneous confinement of current and light

    International Nuclear Information System (INIS)

    Ellis, David J P; Bennett, Anthony J; Dewhurst, Samuel J; Shields, Andrew J; Atkinson, Paola; Nicoll, Christine A; Ritchie, David A


    We report on the development of a generation of microcavity single-photon sources in which an aluminium oxide aperture provides simultaneous confinement of the injected current and the optical mode. The aperture is formed by the wet oxidation of an aluminium-rich AlGaAs layer. This approach allows a high quality cavity to be successfully integrated into an electrical device, from which enhanced photon emission is observed through the Purcell effect. The resulting source demonstrated an improved photon collection efficiency and was shown to operate at repetition rates in excess of 0.5 GHz.

  20. Enhanced photoluminescence by resonant absorption in Er-doped SiO2/Si microcavities (United States)

    Schubert, E. F.; Hunt, N. E. J.; Vredenberg, A. M.; Harris, T. D.; Poate, J. M.; Jacobson, D. C.; Wong, Y. H.; Zydzik, G. J.


    Si/SiO2 Fabry-Perot microcavities with an Er-implanted SiO2 active region resonant at the Er excitation wavelength of 980 nm have been realized. Room-temperature photoluminescence measurements reveal that the Er luminescence intensity increases by a factor of 28 as compared to a structure without cavity enhancement. We show that the experimental enhancement of the luminescence intensity agrees with theory if optical absorption of the 980 nm light in the Si layers of the cavity and reduced mirror reflectivities are taken into account.

  1. Stable gray soliton pinned by a defect in a microcavity-polariton condensate. (United States)

    Chen, Ting-Wei; Hsieh, Wen-Feng; Cheng, Szu-Cheng


    We study the spatially localized dark state, called dark soliton, in a one-dimensional system of the non-resonantly pumped microcavity-polariton condensate (MPC). From the recent work by Xue and Matuszewski [Phys. Rev. Lett. 112, 216401 (2014)], we know that the dark soliton in the pure MPC system is unstable. But we find that a dark soliton pinned by a defect in the impure MPC becomes a gray soliton and can be stabilized by the presence of a defect. Moreover, the stable regime of the gray soliton is given in terms of the defect strength and pump parameter.

  2. Topology optimization of multi-track ring resonators and 2D microcavities for nonlinear frequency conversion. (United States)

    Lin, Zin; Lončar, Marko; Rodriguez, Alejandro W


    We exploit recently developed topology-optimization techniques to design complex, wavelength-scale resonators for enhancing various nonlinear χ(2) and χ(3) frequency conversion processes. In particular, we demonstrate aperiodic, multi-track ring resonators and two-dimensional slab microcavities exhibiting long lifetimes Q≳104, small modal volumes V≳(λ/2n)3, and among the largest nonlinear overlaps (a generalization of phase matching in large-etalon waveguides) possible, paving the way for efficient, compact, and wide-bandwdith integrated nonlinear devices.

  3. Quantum-memory effects in the emission of quantum-dot microcavities. (United States)

    Berger, C; Huttner, U; Mootz, M; Kira, M; Koch, S W; Tempel, J-S; Aßmann, M; Bayer, M; Mintairov, A M; Merz, J L


    The experimentally measured input-output characteristics of optically pumped semiconductor microcavities exhibits unexpected oscillations modifying the fundamentally linear slope in the excitation power regime below lasing. A systematic microscopic analysis reproduces these oscillations, identifying them as a genuine quantum-memory effect, i.e., a photon-density correlation accumulated during the excitation. With the use of projected quantum measurements, it is shown that the input-output oscillations can be controlled and enhanced by an order of magnitude when the quantum fluctuations of the pump are adjusted.

  4. Matrix metalloproteinase sensing via porous silicon microcavity devices functionalized with human antibodies

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Marta; Gergely, Csilla [GES-UMR 5650, CNRS, Universite Montpellier 2, Pl. Eugene Bataillon 34095, Montpellier Cedex 5 (France); Taleb Bendiab, Chakib; Massif, Laurent; Cuisinier, Frederic [EA4203, Faculte d' Odontologie, Universite Montpellier 1, Montpellier Cedex 5 (France); Palestino, Gabriela [Facultad de Ciencias Quimicas, Universidad Autonoma de San Luis Potosi, Av. Salvador Nava 6, 78000 San Luis Potosi (Mexico); Agarwal, Vivechana [CIICAP, Universidad Autonoma del Estado de Morelos, Av. Universidad 1001, Col Chamilpa, Cuernavaca, Mor. (Mexico)


    Porous silicon microcavity (PSiMc) structures were used as support material for specific sensing of matrix metalloproteinases (MMPs). For lower concentrations of MMP-8, the structures were tested with two types of functionalization methods. Silanization of the oxidized porous silicon structures, followed by glutaraldehyde chemistry was found to give very inconsistent results. The use of biotinilated bovine serum albumin linked to the naked PSiMc was found to be an alternative method to attach the anti MMP-8 human antibody, previously modified with streptavidin, which was further used to sense MMP-8 (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  5. Direct evidence of reduced dynamic scattering in the lower polariton of a semiconductor microcavity

    DEFF Research Database (Denmark)

    Borri, Paola; Jensen, Jacob Riis; Langbein, Wolfgang


    The temperature dependent linewidths of homogeneously broadened GaAs/AlxGa1 - xAs microcavity polaritons are investigated. The linewidths of the lower, middle, and upper polariton resonances are measured directly from reflection spectra at normal incidence (k(parallel to) = 0). The Linewidth...... of the lower polariton is found to be smaller than the linewidths of the middle and upper polaritons at all investigated temperatures ranging from 11 to 100 K, The results clearly show the reduction of dynamic scattering processes in the lower polariton compared to the middle and upper polaritons, in agreement...

  6. Circularly polarized lasing in chiral modulated semiconductor microcavity with GaAs quantum wells


    Demenev, A. A.; Kulakovskii, V. D.; Schneider, C.; Brodbeck, S.; Kamp, M.; Höfling, S.; Lobanov, S. V.; Weiss, T.; Gippius, N. A.; Tikhodeev, S. G.


    This work has been funded by Russian Scientific Foundation (Grant No. 14-12-01372) and State of Bavaria. We report close to circularly polarized lasing at ћω = 1.473 and 1.522 eV from an AlAs/AlGaAs Bragg microcavity, with 12 GaAs quantum wells in the active region and chirally etched upper distributed Bragg refractor under optical pump at room temperature. The advantage of using the chiral photonic crystal with a large contrast of dielectric permittivities is its giant optical activity, a...

  7. Alkaline Activator Impact on the Geopolymer Binders (United States)

    Błaszczyński, Tomasz Z.; Król, Maciej R.


    Concrete structures are constantly moving in the direction of improving the durability. Durability depends on many factors, which are the composition of concrete mix, the usage of additives and admixtures and the place, where material will work and carry the load. The introduction of new geopolymer binders for geopolymer structures adds a new aspect that is type of used activator. This substance with strongly alkaline reaction is divided because of the physical state, the alkaline degree and above all the chemical composition. Taking into account, that at present the geopolymer binders are made essentially from waste materials or by-products from the combustion of coal or iron ore smelting, unambiguous determination of the effect of the activator on the properties of the geopolymer material requires a number of trials, researches and observation. This paper shows the influence of the most alkaline activators on the basic parameters of the durability of geopolymer binders. In this study there were used highly alkaline hydroxides, water glasses and granules, which are waste materials in a variety of processes taking place in chemical plants. As the substrate of geopolymer binders there were used fly ash which came from coal and high calcareous ash from the burning of lignite.

  8. Dynamical Fano-Like Interference between Rabi Oscillations and Coherent Phonons in a Semiconductor Microcavity System. (United States)

    Yoshino, S; Oohata, G; Mizoguchi, K


    We report on dynamical interference between short-lived Rabi oscillations and long-lived coherent phonons in CuCl semiconductor microcavities resulting from the coupling between the two oscillations. The Fourier-transformed spectra of the time-domain signals obtained from semiconductor microcavities by using a pump-probe technique show that the intensity of the coherent longitudinal optical phonon of CuCl is enhanced by increasing that of the Rabi oscillation, which indicates that the coherent phonon is driven by the Rabi oscillation through the Fröhlich interaction. Moreover, as the Rabi oscillation frequency decreases upon crossing the phonon frequency, the spectral profile of the coherent phonon changes from a peak to a dip with an asymmetric structure. The continuous wavelet transformation reveals that these peak and dip structures originate from constructive and destructive interference between Rabi oscillations and coherent phonons, respectively. We demonstrate that the asymmetric spectral structures in relation to the frequency detuning are well reproduced by using a classical coupled oscillator model on the basis of dynamical Fano-like interference.

  9. Exciton-polariton in graphene nano-ribbon embedded In semiconductor microcavity

    Energy Technology Data Exchange (ETDEWEB)

    Shojaei, S., E-mail:; Imannezhad, S.


    In this paper, we investigated coupling of confined photons in the semiconductor microcavity consists of Distributed Bragg Reflectors (DBR) (Si{sub 3}N{sub 4}/SiO{sub 2} and AlAs/Al{sub 0.1}Ga{sub 0.9}As) with excitons of gapped Armchair Graphene NanoRibbon (A-GNR) that placed at the maximum of electric field amplitude inside the semiconductor microcavity. Our calculations show that the coupling between GNR's exciton and confined photon modes and appearance of vacuum Rabi splitting (VRS), is possible. By the means of Transfer Matrix Method (TMM) we obtain angle dependent reflectance spectrum and Upper, Lower Polariton Branches (UPB&LPB) for the structure. Clear anticrossing between the neutral exciton and the cavity modes with a splitting of about 3 meV obtained that can be enhanced in double-GNR. While, our calculations certify the formation of graphene based exciton-polariton, propose the enhancement of VRS by optimization of relevant parameters to implement the graphene based cavity polaritons in optoelectronic devices.

  10. Light–matter interaction in a microcavity-controlled graphene transistor (United States)

    Engel, Michael; Steiner, Mathias; Lombardo, Antonio; Ferrari, Andrea C.; Löhneysen, Hilbert v.; Avouris, Phaedon; Krupke, Ralph


    Graphene has extraordinary electronic and optical properties and holds great promise for applications in photonics and optoelectronics. Demonstrations including high-speed photodetectors, optical modulators, plasmonic devices, and ultrafast lasers have now been reported. More advanced device concepts would involve photonic elements such as cavities to control light–matter interaction in graphene. Here we report the first monolithic integration of a graphene transistor and a planar, optical microcavity. We find that the microcavity-induced optical confinement controls the efficiency and spectral selection of photocurrent generation in the integrated graphene device. A twenty-fold enhancement of photocurrent is demonstrated. The optical cavity also determines the spectral properties of the electrically excited thermal radiation of graphene. Most interestingly, we find that the cavity confinement modifies the electrical transport characteristics of the integrated graphene transistor. Our experimental approach opens up a route towards cavity-quantum electrodynamics on the nanometre scale with graphene as a current-carrying intra-cavity medium of atomic thickness. PMID:22713748

  11. Laser-Machined Microcavities for Simultaneous Measurement of High-Temperature and High-Pressure

    Directory of Open Access Journals (Sweden)

    Zengling Ran


    Full Text Available Laser-machined microcavities for simultaneous measurement of high-temperature and high-pressure are demonstrated. These two cascaded microcavities are an air cavity and a composite cavity including a section of fiber and an air cavity. They are both placed into a pressure chamber inside a furnace to perform simultaneous pressure and high-temperature tests. The thermal and pressure coefficients of the short air cavity are ~0.0779 nm/°C and ~1.14 nm/MPa, respectively. The thermal and pressure coefficients of the composite cavity are ~32.3 nm/°C and ~24.4 nm/MPa, respectively. The sensor could be used to separate temperature and pressure due to their different thermal and pressure coefficients. The excellent feature of such a sensor head is that it can withstand high temperatures of up to 400 °C and achieve precise measurement of high-pressure under high temperature conditions.

  12. Magnetic-field induced bistability in a quasi-one-dimensional semiconductor microcavity

    International Nuclear Information System (INIS)

    Zhang, Chuanyi; Zhang, Weifeng


    We theoretically study the magnetic-field induced bistability in a quasi-one-dimensional semiconductor microcavity. A critical magnetic field is obtained, and the bistability appears if a magnetic field is greater than the critical value. For a positive energy detuning of the pump from the bare exciton polaritons, one bistability loop first emerges, then it divides into two loops, and finally one of them vanishes with the increasing magnetic field. This phenomenon originates from the magnetic-field modulated interactions for opposite spins. In the variational process, there are two important effects: one is a logic gate with a small variation of the excitation laser, and the other is a spin texture like skyrmion and this texture is periodic if the energy detuning varies periodically in real space, which is useful for designing the spin-dependent optoelectronic devices. - Highlights: • We study the bistability induced by a magnetic field in a microcavity. • One bistability loop can divide into two, and then the two loops return to one. • A spin texture like skyrmion and logic gate arise in the variation of bistability loop

  13. Tapered optical fiber tip probes based on focused ion beam-milled Fabry-Perot microcavities (United States)

    André, Ricardo M.; Warren-Smith, Stephen C.; Becker, Martin; Dellith, Jan; Rothhardt, Manfred; Zibaii, M. I.; Latifi, H.; Marques, Manuel B.; Bartelt, Hartmut; Frazão, Orlando


    Focused ion beam technology is combined with dynamic chemical etching to create microcavities in tapered optical fiber tips, resulting in fiber probes for temperature and refractive index sensing. Dynamic chemical etching uses hydrofluoric acid and a syringe pump to etch standard optical fibers into cone structures called tapered fiber tips where the length, shape, and cone angle can be precisely controlled. On these tips, focused ion beam is used to mill several different types of Fabry-Perot microcavities. Two main cavity types are initially compared and then combined to form a third, complex cavity structure. In the first case, a gap is milled on the tapered fiber tip which allows the external medium to penetrate the light guiding region and thus presents sensitivity to external refractive index changes. In the second, two slots that function as mirrors are milled on the tip creating a silica cavity that is only sensitive to temperature changes. Finally, both cavities are combined on a single tapered fiber tip, resulting in a multi-cavity structure capable of discriminating between temperature and refractive index variations. This dual characterization is performed with the aid of a fast Fourier transform method to separate the contributions of each cavity and thus of temperature and refractive index. Ultimately, a tapered optical fiber tip probe with sub-standard dimensions containing a multi-cavity structure is projected, fabricated, characterized and applied as a sensing element for simultaneous temperature and refractive index discrimination.

  14. Fabry-Perot Microcavity Modes in Single GaP/GaNP Core/Shell Nanowires. (United States)

    Dobrovolsky, Alexander; Stehr, Jan E; Sukrittanon, Supanee; Kuang, Yanjin; Tu, Charles W; Chen, Weimin M; Buyanova, Irina A


    Semiconductor nanowires (NWs) are attracting increasing interest as nanobuilding blocks for optoelectronics and photonics. A novel material system that is highly suitable for these applications are GaNP NWs. In this article, we show that individual GaP/GaNP core/shell nanowires (NWs) grown by molecular beam epitaxy on Si substrates can act as Fabry-Perot (FP) microcavities. This conclusion is based on results of microphotoluminescence (μ-PL) measurements performed on individual NWs, which reveal periodic undulations of the PL intensity that follow an expected pattern of FP cavity modes. The cavity is concluded to be formed along the NW axis with the end facets acting as reflecting mirrors. The formation of the FP modes is shown to be facilitated by an increasing index contrast with the surrounding media. Spectral dependence of the group refractive index is also determined for the studied NWs. The observation of the FP microcavity modes in the GaP/GaNP core/shell NWs can be considered as a first step toward achieving lasing in this quasidirect bandgap semiconductor in the NW geometry. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Supersonic exciton gratings: coherent inter-polariton scattering in semiconductor microcavities

    DEFF Research Database (Denmark)

    Birkedal, Dan; Vadim, Lyssenko; Hvam, Jørn Märcher


    We report on a coherent nonlinear phenomenon in a semiconductor microcavity (SMC), which has no parallel for QW excitons. When two different polariton modes of the SMC are impulsively excited they undergo normal mode oscillations (NMOs) with coherent energy exchange between the exciton and the ca......We report on a coherent nonlinear phenomenon in a semiconductor microcavity (SMC), which has no parallel for QW excitons. When two different polariton modes of the SMC are impulsively excited they undergo normal mode oscillations (NMOs) with coherent energy exchange between the exciton...... and the cavity mode. In our experiment the two polaritons are excited with slightly different angles resulting in a travelling wave exciton grating. When a test polariton mode is excited it will scatter in the travelling grating producing amplitude modulation sidebands. This phenomenon produces a transient four......-wave mixing (TFWM) signal, which is shifted in frequency from that of the test beam by the NMO frequency, in our case, in the THz range corresponding to a grating velocity = 1 /spl times/ 10/sup 7/ m/s, which is four orders of magnitude larger than the sound velocity. The sample under investigation is a Ga...

  16. Modelling Laser Milling of Microcavities for the Manufacturing of DES with Ensembles

    Directory of Open Access Journals (Sweden)

    Pedro Santos


    Full Text Available A set of designed experiments, involving the use of a pulsed Nd:YAG laser system milling 316L Stainless Steel, serve to study the laser-milling process of microcavities in the manufacture of drug-eluting stents (DES. Diameter, depth, and volume error are considered to be optimized as functions of the process parameters, which include laser intensity, pulse frequency, and scanning speed. Two different DES shapes are studied that combine semispheres and cylinders. Process inputs and outputs are defined by considering the process parameters that can be changed under industrial conditions and the industrial requirements of this manufacturing process. In total, 162 different conditions are tested in a process that is modeled with the following state-of-the-art data-mining regression techniques: Support Vector Regression, Ensembles, Artificial Neural Networks, Linear Regression, and Nearest Neighbor Regression. Ensemble regression emerged as the most suitable technique for studying this industrial problem. Specifically, Iterated Bagging ensembles with unpruned model trees outperformed the other methods in the tests. This method can predict the geometrical dimensions of the machined microcavities with relative errors related to the main average value in the range of 3 to 23%, which are considered very accurate predictions, in view of the characteristics of this innovative industrial task.

  17. Ultrafast control of strong light–matter coupling (United States)

    Lange, Christoph; Cancellieri, Emiliano; Panna, Dmitry; Whittaker, David M.; Steger, Mark; Snoke, David W.; Pfeiffer, Loren N.; West, Kenneth W.; Hayat, Alex


    We dynamically modulate strong light–matter coupling in a GaAs/AlGaAs microcavity using intense ultrashort laser pulses tuned below the interband exciton energy, which induce a transient Stark shift of the cavity polaritons. For 225-fs pulses, shorter than the cavity Rabi cycle period of 1000 fs, this shift decouples excitons and cavity photons for the duration of the pulse, interrupting the periodic energy exchange between photonic and electronic states. For 1500-fs pulses, longer than the Rabi cycle period, however, the Stark shift does not affect the strong coupling. The two regimes are marked by distinctly different line shapes in ultrafast reflectivity measurements—regardless of the Stark field intensity. The crossover marks the transition from adiabatic to diabatic switching of strong light–matter coupling.

  18. Microcavity arrays as an in vitro model system of the bone marrow niche for hematopoietic stem cells. (United States)

    Wuchter, Patrick; Saffrich, Rainer; Giselbrecht, Stefan; Nies, Cordula; Lorig, Hanna; Kolb, Stephanie; Ho, Anthony D; Gottwald, Eric


    In previous studies human mesenchymal stromal cells (MSCs) maintained the "stemness" of human hematopoietic progenitor cells (HPCs) through direct cell-cell contact in two-dimensional co-culture systems. We establish a three-dimensional (3D) co-culture system based on a custom-made chip, the 3(D)-KITChip, as an in vitro model system of the human hematopoietic stem cell niche. This array of up to 625 microcavities, with 300 μm size in each orientation, was inserted into a microfluidic bioreactor. The microcavities of the 3(D)-KITChip were inoculated with human bone marrow MSCs together with umbilical cord blood HPCs. MSCs used the microcavities as a scaffold to build a complex 3D mesh. HPCs were distributed three-dimensionally inside this MSC network and formed ß-catenin- and N-cadherin-based intercellular junctions to the surrounding MSCs. Using RT(2)-PCR and western blots, we demonstrate that a proportion of HPCs maintained the expression of CD34 throughout a culture period of 14 days. In colony-forming unit assays, the hematopoietic stem cell plasticity remained similar after 14 days of bioreactor co-culture, whereas monolayer co-cultures showed increasing signs of HPC differentiation and loss of stemness. These data support the notion that the 3D microenvironment created within the microcavity array preserves vital stem cell functions of HPCs more efficiently than conventional co-culture systems.

  19. Advances in optoplasmonic sensors - combining optical nano/microcavities and photonic crystals with plasmonic nanostructures and nanoparticles (United States)

    Xavier, Jolly; Vincent, Serge; Meder, Fabian; Vollmer, Frank


    Nanophotonic device building blocks, such as optical nano/microcavities and plasmonic nanostructures, lie at the forefront of sensing and spectrometry of trace biological and chemical substances. A new class of nanophotonic architecture has emerged by combining optically resonant dielectric nano/microcavities with plasmonically resonant metal nanostructures to enable detection at the nanoscale with extraordinary sensitivity. Initial demonstrations include single-molecule detection and even single-ion sensing. The coupled photonic-plasmonic resonator system promises a leap forward in the nanoscale analysis of physical, chemical, and biological entities. These optoplasmonic sensor structures could be the centrepiece of miniaturised analytical laboratories, on a chip, with detection capabilities that are beyond the current state of the art. In this paper, we review this burgeoning field of optoplasmonic biosensors. We first focus on the state of the art in nanoplasmonic sensor structures, high quality factor optical microcavities, and photonic crystals separately before proceeding to an outline of the most recent advances in hybrid sensor systems. We discuss the physics of this modality in brief and each of its underlying parts, then the prospects as well as challenges when integrating dielectric nano/microcavities with metal nanostructures. In Section 5, we hint to possible future applications of optoplasmonic sensing platforms which offer many degrees of freedom towards biomedical diagnostics at the level of single molecules.

  20. Alkaline fuel cells applications (United States)

    Kordesch, Karl; Hacker, Viktor; Gsellmann, Josef; Cifrain, Martin; Faleschini, Gottfried; Enzinger, Peter; Fankhauser, Robert; Ortner, Markus; Muhr, Michael; Aronson, Robert R.

    On the world-wide automobile market technical developments are increasingly determined by the dramatic restriction on emissions as well as the regimentation of fuel consumption by legislation. Therefore there is an increasing chance of a completely new technology breakthrough if it offers new opportunities, meeting the requirements of resource preservation and emission restrictions. Fuel cell technology offers the possibility to excel in today's motive power techniques in terms of environmental compatibility, consumer's profit, costs of maintenance and efficiency. The key question is economy. This will be decided by the costs of fuel cell systems if they are to be used as power generators for future electric vehicles. The alkaline hydrogen-air fuel cell system with circulating KOH electrolyte and low-cost catalysed carbon electrodes could be a promising alternative. Based on the experiences of Kordesch [K. Kordesch, Brennstoffbatterien, Springer, Wien, 1984, ISBN 3-387-81819-7; K. Kordesch, City car with H 2-air fuel cell and lead-battery, SAE Paper No. 719015, 6th IECEC, 1971], who operated a city car hybrid vehicle on public roads for 3 years in the early 1970s, improved air electrodes plus new variations of the bipolar stack assembly developed in Graz are investigated. Primary fuel choice will be a major issue until such time as cost-effective, on-board hydrogen storage is developed. Ammonia is an interesting option. The whole system, ammonia dissociator plus alkaline fuel cell (AFC), is characterised by a simple design and high efficiency.

  1. Method of cleaning alkaline metal

    International Nuclear Information System (INIS)

    Kawakami, Yukio; Naito, Kesahiro; Iizawa, Katsuyuki; Nakasuji, Takashi


    Purpose: To prevent scattering of used sodium and aqueous alkaline solution when cleaning used sodium and metallic sodium adhering to equipment with an aqueous alkaline solution. Method: A sodium treating container is filled with an aqueous alkaline solution, and stainless steel gauze is sunk in the container. Equipment to be cleaned such as equipment with sodium adhering to it are retained under the gauze and are thus cleaned. On the other hand, the surface of the aqueous alkaline solution is covered with a fluid paraffin liquid covering material. Thus, the hydrogen produced by the reaction of the sodium and the aqueous alkaline solution will float up, pass through the liquid covering material and be discharged. The sodium will pass through the gauze and float upwardly while reacting with the aqueous alkaline solution in a partic ulate state to the boundary between the aqueous alkaline solution and up to the covering material, and thus the theratment reaction will continue. Thus, the cover material prevents the sodium and the aqueous alkaline solution from scattering. (Kamimura, M.)

  2. Alkaline direct alcohol fuel cells (United States)

    Antolini, E.; Gonzalez, E. R.

    The faster kinetics of the alcohol oxidation and oxygen reduction reactions in alkaline direct alcohol fuel cells (ADAFCs), opening up the possibility of using less expensive metal catalysts, as silver, nickel and palladium, makes the alkaline direct alcohol fuel cell a potentially low cost technology compared to acid direct alcohol fuel cell technology, which employs platinum catalysts. A boost in the research regarding alkaline fuel cells, fuelled with hydrogen or alcohols, was due to the development of alkaline anion-exchange membranes, which allows the overcoming of the problem of the progressive carbonation of the alkaline electrolyte. This paper presents an overview of catalysts and membranes for ADAFCs, and of testing of ADAFCs, fuelled with methanol, ethanol and ethylene glycol, formed by these materials.

  3. Influence of carrier relaxation on the dynamics of stimulated emission in microcavity lasers (United States)

    Hilpert, M.; Klann, H.; Hofmann, M.; Ellmers, C.; Oestreich, M.; Schneider, H. C.; Jahnke, F.; Koch, S. W.; Rühle, W. W.; Wolf, H. D.; Bernklau, D.; Riechert, H.


    The influence of carrier relaxation on the emission dynamics of a semiconductor microcavity laser is investigated using femtosecond optical excitation. For moderate excitation intensities, the dynamics of the output laser pulse becomes significantly slower when the photon energy of the pump laser is tuned from the quantum well band-gap energy towards higher energies. Theoretical calculations reproduce this trend only if the interaction-induced dephasing of the polarization driven by the pump pulse, the formation, and relaxation of the nonequilibrium carrier distribution as well as the chirp of the excitation pulse are taken into account. Additionally, band-structure effects such as excitation of light holes influence the thermalization dynamics and lead to discontinuities in the general trend.

  4. Robust nano-fabrication of an integrated platform for spin control in a tunable microcavity (United States)

    Bogdanović, Stefan; Liddy, Madelaine S. Z.; van Dam, Suzanne B.; Coenen, Lisanne C.; Fink, Thomas; Lončar, Marko; Hanson, Ronald


    Coupling nitrogen-vacancy (NV) centers in diamonds to optical cavities is a promising way to enhance the efficiency of diamond-based quantum networks. An essential aspect of the full toolbox required for the operation of these networks is the ability to achieve the microwave control of the electron spin associated with this defect within the cavity framework. Here, we report on the fabrication of an integrated platform for the microwave control of an NV center electron spin in an open, tunable Fabry-Pérot microcavity. A critical aspect of the measurements of the cavity's finesse reveals that the presented fabrication process does not compromise its optical properties. We provide a method to incorporate a thin diamond slab into the cavity architecture and demonstrate the control of the NV center spin. These results show the promise of this design for future cavity-enhanced NV center spin-photon entanglement experiments.

  5. Self-sustained photothermal oscillations in high-finesse Fabry-Perot microcavities (United States)

    Konthasinghe, Kumarasiri; Velez, Juan Gomez; Hopkins, Adam J.; Peiris, Manoj; Profeta, Luisa T. M.; Nieves, Yamil; Muller, Andreas


    We report the experimental investigation of a regime of microscopic Fabry-Perot resonators in which competing light-induced forces—photothermal expansion and photothermal refraction—acting oppositely and on different timescales lead to self-sustained persistent oscillations. Previously concealed as ordinary thermo-optic bistability—a common feature in low-loss resonator physics—these dynamics are visible as fast pulsations in cavity transmission or reflection measurements at sufficiently high time resolution. Their underlying mathematical description is shared by many slow-fast phenomena in chemistry, biology, and neuroscience. Our observations are relevant in particular to microcavity applications in atom optics and cavity quantum electrodynamics, even in nominally rigid structures that have not undergone lithography.

  6. On-Chip High-Finesse Fabry-Perot Microcavities for Optical Sensing and Quantum Information

    Directory of Open Access Journals (Sweden)

    Mohammad H. Bitarafan


    Full Text Available For applications in sensing and cavity-based quantum computing and metrology, open-access Fabry-Perot cavities—with an air or vacuum gap between a pair of high reflectance mirrors—offer important advantages compared to other types of microcavities. For example, they are inherently tunable using MEMS-based actuation strategies, and they enable atomic emitters or target analytes to be located at high field regions of the optical mode. Integration of curved-mirror Fabry-Perot cavities on chips containing electronic, optoelectronic, and optomechanical elements is a topic of emerging importance. Micro-fabrication techniques can be used to create mirrors with small radius-of-curvature, which is a prerequisite for cavities to support stable, small-volume modes. We review recent progress towards chip-based implementation of such cavities, and highlight their potential to address applications in sensing and cavity quantum electrodynamics.

  7. Manipulation of exciton and photon lasing in a membrane-type ZnO microcavity (United States)

    Lai, Ying-Yu; Chen, Jee-Wei; Chang, Tsu-Chi; Chou, Yu-Hsun; Lu, Tien-Chang


    We report on the fabrication and characterization of a membrane-type ZnO microcavity (MC). The ZnO membrane was cut from a single crystalline ZnO substrate by using focused ion beam milling, and was then placed onto a SiO2 substrate by using glass microtweezers. Through changing the pumping regime, manipulation of P-band exciton lasing and whispering-gallery mode (WGM) photon lasing could be easily achieved. P-band exciton lasing was observed only when the pumping laser was focused at the center of the ZnO MC with a small pumping size because of the innate ring-shaped WGM distribution. Furthermore, the lasing threshold of the ZnO MC could be reduced to an order lower by using a larger pumping spot because of the more favorable spatial overlap between the optical gain and WGM.

  8. Mass and Momentum Transport in Microcavities for Diffusion-Dominant Cell Culture Applications (United States)

    Yew, Alvin G.; Pinero, Daniel; Hsieh, Adam H.; Atencia, Javier


    For the informed design of microfluidic devices, it is important to understand transport phenomena at the microscale. This letter outlines an analytically-driven approach to the design of rectangular microcavities extending perpendicular to a perfusion microchannel for microfluidic cell culture devices. We present equations to estimate the spatial transition from advection- to diffusion-dominant transport inside cavities as a function of the geometry and flow conditions. We also estimate the time required for molecules, such as nutrients or drugs to travel from the microchannel to a given depth into the cavity. These analytical predictions can facilitate the rational design of microfluidic devices to optimize and maintain long-term, physiologically-based culture conditions with low fluid shear stress.

  9. Toroidal hollow-core microcavities produced by self-rolling of strained polymer bilayer films (United States)

    Luchnikov, V.; Kumar, K.; Stamm, M.


    Hollow-core toroidal micro-cavities are obtained by self-rolling of double-layer (polyvinyl pyridine/polystyrole) polymer films. Rolling of the bilayer is due to preferential swelling of polyvinyl pyridine in water solution of dodecyl benzene sulfonic acid. The tube formation proceeds from a circular opening in the film made by photolithography or by mechanical scratching. Toroid equilibrium dimensions are determined by the balance of the elastic energy relaxation via the film scrolling and the work of the in-plane stretching that is due to increasing radius of the toroid. The principle features of the micro-toroid formation process are captured by a simple analytical model. The inner walls of the cavities can be made metal coated. For this aim, the polymer bilayer can be metallized by vacuum sputtering prior to lithographic patterning and rolling of the bilayer. The toroids with metallic inner surfaces are promising for the future research as IR-frequency range resonators.

  10. Mono- to few-layered graphene oxide embedded randomness assisted microcavity amplified spontaneous emission source (United States)

    Das, Pratyusha; Maiti, Rishi; Barman, Prahalad K.; Ray, Samit K.; Shivakiran, Bhaktha B. N.


    The realization of optoelectronic devices using two-dimensional materials such as graphene and its intermediate product graphene oxide (GO) is extremely challenging owing to the zero band gap of the former. Here, a novel amplified spontaneous emission (ASE) system based on a GO-embedded all-dielectric one-dimensional photonic crystal (1DPhC) micro-resonator is presented. The mono- to few-layered GO sheet is inserted within a microcavity formed by two 5-bilayered SiO2/SnO2 Bragg reflectors. Significantly enhanced photoluminescence (PL) emission of GO embedded in 1DPhC is explicated by studying the electric field confined within the micro-resonator using the transfer matrix method. The inherent randomness, due to fabrication limitations, in the on-average periodic 1DPhC is exploited to further enhance the PL of the optically active micro-resonator. The 1DPhC and randomness assisted field confinement reduces the ASE threshold of the mono- to few-layered weak emitter making the realization of an ASE source feasible. Consequently, ASE at the microcavity resonance and at the low-frequency band-edge of photonic stop-band is demonstrated. Variation of the detection angle from 5° to 30°, with respect to the sample surface normal allows reallocation of the defect mode ASE peak over a spectral range of 558-542 nm, making the GO-incorporated 1DPhC a novel and attractive system for integrated optic applications.

  11. Alkaline Material Effects on Roots of Teeth

    Directory of Open Access Journals (Sweden)

    Sowmya Shetty


    Full Text Available The aim of this review was to identify and analyse all studies related to the effects of alkaline materials used in dentistry on roots of teeth. The first part of the review focused on mechanical property alterations of root dentine due to sodium hypochlorite (SH used as an irrigant solution based on MeSH (Medical Subject Heading terms from a previous study by Pascon et al in 2009. The second part reviewed literature on calcium hydroxide (CH, mineral trioxide aggregate (MTA and other alkaline materials used as root canal dressings or filling materials. Additional MeSH terms used included “compressive strength”, “elastic modulus” “flexural strength”, “fracture strength” and “fracture resistance”. The language filter was English. Of the initial 205 articles identified, 49 were included in this review, of which 29 were on SH, 21 on CH/MTA, and 1 relating to both. Many in vitro studies indicated a strong link between reduced mechanical properties of roots of teeth or radicular dentine treated with SH, and when sealers or root fillings with CH- or MTA-based materials were placed in contact with roots or radicular dentine. Recent literature indicates that the association between reduced mechanical properties and alkaline sealers and/or root-filling materials is not as straightforward as previously assumed, and requires further investigation using more valid experimental models.

  12. Microcavity structures

    International Nuclear Information System (INIS)

    Kustom, R.L.; Grudzien, D.; Feinerman, A.D.


    The feasibility of building mm-wave cavities using deep x-ray lithography techniques is being investigated. These cavities could be considered for linac accelerating structures, undulators, free electron lasers, or mm-wave amplifiers. The construction process includes making precision x-ray masks, x-ray exposure of poly-methyl-methacrylate (PMMA), removal of PMMA, and electroplating a metal. Highly precise two-dimensional features can be machined onto wafers by this technique. The challenge is to fabricate the wafers onto three-dimensional rf structures. Rectangular cavity geometry is best suited to this fabrication technique. Status of wafer manufacture, fabrication and alignment techniques using capillaries bonded in precision grooves, 2π/3 120-GHz linac structures, heat extraction analysis, and beam dynamics in a 5-meter-long 50-MeV linac will be discussed. Measurements made on 10X larger scale models that were built with conventional techniques will also be discussed

  13. Broad-spectrum enhanced absorption of graphene-molybdenum disulfide photovoltaic cells in metal-mirror microcavity (United States)

    Jiang-Tao, Liu; Yun-Kai, Cao; Hong, Tong; Dai-Qiang, Wang; Zhen-Hua, Wu


    The optical absorption of graphene-molybdenum disulfide photovoltaic cells (GM-PVc) in wedge-shaped metal-mirror microcavities (w-MMCs) combined with a spectrum-splitting structure was studied. Results showed that the combination of spectrum-splitting structure and w-MMC can enable the light absorption of GM-PVcs to reach about 65% in the broad spectrum. The influence of processing errors on the absorption of GM-PVcs in w-MMCs was 3-14 times lower than that of GM-PVcs in wedge photonic crystal microcavities. The light absorption of GM-PVcs reached 60% in the broad spectrum, even with the processing errors. The proposed structure is easy to implement and may have potentially important applications in the development of ultra-thin and high-efficiency solar cells and optoelectronic devices.

  14. High-fidelity quantum gates on quantum-dot-confined electron spins in low-Q optical microcavities (United States)

    Li, Tao; Gao, Jian-Cun; Deng, Fu-Guo; Long, Gui-Lu


    We propose some high-fidelity quantum circuits for quantum computing on electron spins of quantum dots (QD) embedded in low-Q optical microcavities, including the two-qubit controlled-NOT gate and the multiple-target-qubit controlled-NOT gate. The fidelities of both quantum gates can, in principle, be robust to imperfections involved in a practical input-output process of a single photon by converting the infidelity into a heralded error. Furthermore, the influence of two different decay channels is detailed. By decreasing the quality factor of the present microcavity, we can largely increase the efficiencies of these quantum gates while their high fidelities remain unaffected. This proposal also has another advantage regarding its experimental feasibility, in that both quantum gates can work faithfully even when the QD-cavity systems are non-identical, which is of particular importance in current semiconductor QD technology.

  15. Sodic alkaline stress mitigation by exogenous melatonin in tomato needs nitric oxide as a downstream signal. (United States)

    Liu, Na; Gong, Biao; Jin, Zhiyong; Wang, Xiufeng; Wei, Min; Yang, Fengjuan; Li, Yan; Shi, Qinghua


    The present study was designed to determine the interactive effect of exogenous melatonin and nitric oxide (NO) on sodic alkaline stress mitigation in tomato seedlings. It was observed that exogenous melatonin treatment elevated NO levels in alkaline-stressed tomato roots. However, exogenous NO had little effects on melatonin levels. Importantly, melatonin-induced NO generation was accompanied by increased tolerance to alkaline stress. Chemical scavenging of NO reduced melatonin-induced alkaline stress tolerance and defense genes' expression. However, inhibition of melatonin biosynthesis had a little effect on NO-induced alkaline stress tolerance. These results strongly suggest that NO, acting as a downstream signal, is involved in the melatonin-induced tomato tolerance to alkaline stress. This process creates a new signaling pathway for improving stress tolerance in plant. Copyright © 2015 Elsevier GmbH. All rights reserved.

  16. Escape of quantum particles from an open nano-circular microcavity

    International Nuclear Information System (INIS)

    Liu, Sheng; Wang, De-hua


    When a laser is irradiated on a negative ion, it will provide a coherent, mono-energetic source of detached electrons propagating out from the location of the negative ion. The total escape probability density of the electrons when the negative ion is placed inside an open nano-circular microcavity has been studied on the basis of the semiclassical theory. It is shown that significant oscillations appear in the total escape probability density due to the quantum interference effects. Besides, our study suggests that the escape probability density depends on the laser polarization sensitively. In order to show the correspondence between the escaped probability density and the detached electron's escaped orbits clearly, we calculate the path length spectrum and find that each peak corresponds to the length of one detached electron's escaped orbit. This study provides an example where the quantum nature of the electron's wave function can be observed in the macroscopic world. Our study may guide the future experimental research on the escape and transport process of particles through semiconductor microjunctions.

  17. Microcavity Silicon Photodetectors at 1.55 μm

    Directory of Open Access Journals (Sweden)

    M. Casalino


    Full Text Available The design, the realization, and the characterization of silicon resonant cavity enhanced (RCE photodetectors, working at 1.55 μm, are reported. The photodetectors are constituted by a Fabry-Perot microcavity incorporating a Schottky diode. The working principle is based on the internal photoemission effect. We investigated two types of structures: top and back-illuminated. Concerning the top-illuminated photodetectors, a theoretical and numerical analysis has been provided and the device quantum efficiency has been calculated. Moreover, a comparison among three different photodetectors, having as Schottky metal: gold, silver, or copper, was proposed. Concerning the back-illuminated devices, two kinds of Cu/p-Si RCE photodetectors, having various bottom-mirror reflectivities, were realized and characterized. Device performances in terms of responsivity, free spectral range, and finesse were theoretically and experimentally calculated in order to prove an enhancement in efficiency due to the cavity effect. The back-illuminated device fabrication process is completely compatible with the standard silicon technology.

  18. Controllable structuring of exciton-polariton condensates in cylindrical pillar microcavities (United States)

    Kalevich, V. K.; Afanasiev, M. M.; Lukoshkin, V. A.; Solnyshkov, D. D.; Malpuech, G.; Kavokin, K. V.; Tsintzos, S. I.; Hatzopoulos, Z.; Savvidis, P. G.; Kavokin, A. V.


    We observe condensation of exciton polaritons in quantum states composed of concentric rings when exciting cylindrical pillar GaAs/AlGaAs microcavities nonresonantly by a focused laser beam normally incident at the center of the pillar. The number of rings depends on the pumping intensity and the pillar size, and may achieve 5 in the pillar of 40 μ m diameter. Breaking the axial symmetry when moving the excitation spot away from the pillar center leads to transformation of the rings into a number of bright lobes corresponding to quantum states with nonzero angular momenta. The number of lobes, their shape, and location are dependent on the spot position. We describe the out-of-equilibrium condensation of polaritons in the states with different principal quantum numbers and angular momenta with a formalism based on Boltzmann-Gross-Pitaevskii equations accounting for repulsion of polaritons from the exciton reservoir formed at the excitation spot and their spatial confinement by the pillar boundary.

  19. Electrically Pumped III-N Microcavity Light Emitters Incorporating an Oxide Confinement Aperture (United States)

    Lai, Ying-Yu; Chang, Tsu-Chi; Li, Ya-Chen; Lu, Tien-Chang; Wang, Shing-Chung


    In this work, we report on electrically pumped III-N microcavity (MC) light emitters incorporating oxide confinement apertures. The utilized SiO2 aperture can provide a planar ITO design with a higher index contrast ( 1) over other previously reported approaches. The fabricated MC light emitter with a 15-μm-aperture shows a turn-on voltage of 3.3 V, which is comparable to conventional light emitting diodes (LEDs), showing a good electrical property of the proposed structure. A uniform light output profile within the emission aperture suggesting the good capability of current spreading and current confinement of ITO and SiO2 aperture, respectively. Although the quality factor ( Q) of fabricated MC is not high enough to achieve lasing action ( 500), a superlinear emission can still be reached under a high current injection density (2.83 kA/cm2) at 77 K through the exciton-exciton scattering, indicating the high potential of this structure for realizing excitonic vertical-cavity surface-emitting laser (VCSEL) action or even polariton laser after fabrication optimization.

  20. Detection of MMP-8 via porous silicon microcavity devices functionalized with human antibodies (United States)

    Martin, Marta; Taleb Bendiab, Chakib; Massif, Laurent; Cuisinier, Frédéric J. G.; Gergely, Csilla


    In this work we report on the fabrication of functionalized PSiMc scaffolds that can be used to enhance the detection of MMP-8. Matrix metalloproteinases (MMPs) are the major enzymes that degrade extracellular matrix (ECM) proteins and play a key role in diverse physiological and pathological processes. We are interested in detecting the collagenase-type MMP-8 that is an inflammatory marker in gingival fluid for predicting tooth movement during orthodontic treatment. As presence of an increasing amount of MMP-8 in saliva is directly related with the tooth movement during orthodontic treatment, monitoring continuously the MMP-8 variation is primordial. Porous silicon microcavity (PSiMc) structures were prepared as multilayered stacks of low and high refractive indices and with layer thicknesses in the order of visible light wavelength. Then the PSi surface was functionalized with human antibodies. Both functionalization and MMP-8 infiltration were monitored by specular reflectometry. PSiMc is characterized by a narrow resonance peak in the optical spectrum that is very sensitive to a small change in the refractive index, such as that obtained when a molecule is attached to the large internal surface of porous silicon. The pore dimensions of the used PSiMc structures were evaluated by atomic force microscopy (AFM) and scanning electron microscope (SEM).

  1. Limulus amoebocyte lysate test via an open-microcavity optical biosensor (United States)

    Scudder, Jonathan; Ye, Jing Yong


    Almost since its discovery, Limulus amoebocyte lysate (LAL) testing has been an important part of the pharmaceutical quality control toolkit. It allows for in vitro endotoxin testing, which has replaced tests using animals, such as using rabbits' thermal response to judge pyrogenicity of test samples, thus leading to a less expensive and faster test of parenteral pharmaceuticals and medical devices that contact blood or cerebrospinal fluid. However, limited by the detection mechanisms of the LAL assays currently used in industry, further improvement in their performance is challenging. To address the growing demand on optimizing LAL assays for increased test sensitivity and reduced assay time, we have developed an LAL assay approach based on a detection mechanism that is different from those being used in industry, namely, gel-clot, turbidimetric, and chromogenic detection. Using a unique open-microcavity photonic-crystal biosensor to monitor the change in the refractive index due to the reaction between LAL regents and endotoxins, we have demonstrated that this approach has improved the LAL assay sensitivity by 200 times compared with the commercial standard methods, reduced the time needed for the assay by more than half, and eliminated the necessity to incubate the test samples. This study opens up the possibility of using the significantly improved LAL assays for a wide range of applications.

  2. Three-visible-light wave combiner based on photonic crystal microcavities. (United States)

    Zhou, Xiaoyi; Liu, Dingwen; Sun, Yiling; Ouyang, Zhengbiao


    We propose a three-visible-light wave combiner based on two-dimensional square-lattice photonic crystal (PhC) microcavities. A coupled-cavity waveguide is introduced to reduce the insertion losses for the three waves in the combiner. The transmission characteristic of light waves in PhCs with point defects is analyzed. As an example, a combiner for combining light waves of 488, 532, and 635 nm, which are commonly used as the three primary colors in laser display systems, is designed and demonstrated through the finite-difference time-domain method. The three visible light waves of 488, 532, and 635 nm are output at the same output port with transmittances of 97.6%, 98.1%, and 90.0%, respectively. The results show that the proposed device can perform efficient synthesis and the designing method can be applied in building other combiners based on PhCs made of dispersion materials.

  3. 2nd Generation Alkaline Electrolysis

    DEFF Research Database (Denmark)

    Yde, Lars; Kjartansdóttir, Cecilia Kristin; Allebrod, Frank

    This report provides the results of the 2nd Generation Alkaline Electrolysis project which was initiated in 2008. The project has been conducted from 2009-2012 by a consortium comprising Århus University Business and Social Science – Centre for Energy Technologies (CET (former HIRC)), Technical...

  4. Zinc electrode in alkaline electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    McBreen, J.


    The zinc electrode in alkaline electrolyte is unusual in that supersaturated zincate solutions can form during discharge and spongy or mossy zinc deposits can form on charge at low overvoltages. The effect of additives on regular pasted ZnO electrodes and calcium zincate electrodes is discussed. The paper also reports on in situ x-ray absorption (XAS) results on mossy zinc deposits.

  5. Detection of protein kinases P38 based on reflectance spectroscopy with n-type porous silicon microcavities for diagnosing hydatidosis hydatid disease (United States)

    Lv, Xiaoyi; Lv, Guodong; Jia, Zhenhong; Wang, Jiajia; Mo, Jiaqing


    Detection of protein kinases P38 of Echinococcus granulosus and its homologous antibody have great value for early diagnosis and treatment of hydatidosis hydatid disease. In this experiment, n-type mesoporous silicon microcavities have been successfully fabricated without KOH etching or oxidants treatment that reported in other literature. We observed the changes of the reflectivity spectrum before and after the antigen-antibody reaction by n-type mesoporous silicon microcavities. The binding of protein kinases P38 and its homologous antibody causes red shifts in the reflection spectrum of the sensor, and the red shift was proportional to the protein kinases P38 concentration with linear relationship.

  6. Electrochemical behaviour of alkaline copper complexes

    Indian Academy of Sciences (India)

    cyanide- plating bath for copper has been developed using alkaline trisodium citrate and triethanolamine solutions5. The present investigation presents cyclic voltammetric studies on the electrochemical behaviour of alkaline copper complexes, ...

  7. Utilizing an open-microcavity optoacoustic sensor for spectroscopic determination of methemoglobin concentration (United States)

    Peterson, Ralph W.; Kadugodinandareddy, Kavya; Karunakaran, Vinitha; Whitney, Casey; Ling, Jian; Ye, Jing Yong


    We present a simple, non-destructive photoacoustic spectroscopy method utilizing a unique open-microcavity optoacoustic sensor to measure the concentration ratio of Methemoglobin (MetHb) in an optically scattering medium. Elevated levels of MetHb, present for example in the blood disorder Methemeglobinemia, cannot be detected by conventional pulse oximetry, and may result in inaccurate arterial oxygen saturation measurements. Samples with different ratios of Oxygenated Hemoglobin (HbO2), Deoxygenated Hemoglobin (HHb), and MetHb were obtained and mixed with nanoscale latex beads to present an optical scattering effect. Polymer encapsulated hemoglobin (PEH) samples were also studied. A sample chamber containing 20 μL of each sample was positioned directly underneath our patented optoacoustic sensor. Unlike a piezoelectric transducer, our optoacoustic sensor allows an excitation laser beam from an OPO laser to pass through and be absorbed by the sample to produce a photoacoustic signal. The cavity layer of the optoacoustic sensor is exposed directly to the resulting ultrasound signal, which causes an intensity modulation of a HeNe laser that is used to monitor the resonance condition of the sensor. A probe laser beam is total internally reflected off of the sensor and detected with a fiber-coupled APD detector. Three wavelengths are chosen for our excitation laser based on the absorption peaks and isobestic points of HHb, HbO2, and MetHb. Using established values of the molar extinction coefficients of HbO2, HHb, and MetHb a set of three simultaneous equations can be solved to accurately determine the concentration ratio of MetHb.

  8. All-optical control of weak-light transport and Fano-like resonance using control-probe technique in a quantum-dot-pillar microcavity system (United States)

    Yu, Rong; Ding, Chunling; Zhang, Duo; Zhang, Suzhen


    Control of light by light is a current research topic and is important for a variety of fundamental studies and practical applications. Here, we put forward a chip-scale scheme for all-optical control of small-signal photon transport and Fano-like lineshape in a coupled quantum-dot-pillar microcavity system based on a control-probe technique. Specifically, a bichromatic input light field, which consists of a weak probe field and a tunable control field, is applied to simultaneously drive the pillar cavity mode (called the control-probe technique) and both its reflectivity from and transmittivity through the pillar cavity constitute two output channels (i.e., a reflectivity signal channel and a transmittivity signal channel). We derive full analytical expressions for the reflectivity and transmittivity coefficients via a perturbation method. Using experimentally realistic parameters, theoretical analysis shows that the output probe light of the reflectivity and transmittivity channels can be switched on or off by simply turning on or off the control light field. Hence, the present system can be utilized to realize all-optical switching of the probe light by the control light with high switching contrast ˜ 1 by means of these two output channels. Interestingly, the reflectivity channel and the transmittivity channel are complementary and offer versatile applications in a two-channel switching. In addition, it is shown that the strong asymmetric Fano lineshape can be generated by properly tuning the frequency of the control light field in this control-probe scheme. The present investigation may be used for developing novel all-optical switching and tunable Fano devices on-chip.

  9. Near-Field Integration of a SiN Nanobeam and a SiO2 Microcavity for Heisenberg-Limited Displacement Sensing (United States)

    Schilling, R.; Schütz, H.; Ghadimi, A. H.; Sudhir, V.; Wilson, D. J.; Kippenberg, T. J.


    Placing a nanomechanical object in the evanescent near field of a high-Q optical microcavity gives access to strong gradient forces and quantum-limited displacement readout, offering an attractive platform for both precision sensing technology and basic quantum optics research. Robustly implementing this platform is challenging, however, as it requires integrating optically smooth surfaces separated by ≲λ /10 . Here we describe an exceptionally high-cooperativity, single-chip optonanomechanical transducer based on a high-stress Si3N4 nanobeam monolithically integrated into the evanescent near field of SiO2 microdisk cavity. Employing a vertical integration technique based on planarized sacrificial layers, we realize beam-disk gaps as little as 25 nm while maintaining mechanical Q f >1012 Hz and intrinsic optical Q ˜107. The combination of low loss, small gap, and parallel-plane geometry results in radio-frequency flexural modes with vacuum optomechanical coupling rates of 100 kHz, single-photon cooperativities in excess of unity, and large zero-point frequency (displacement) noise amplitudes of 10 kHz (fm )/√ Hz . In conjunction with the high power-handling capacity of SiO2 and low extraneous substrate noise, the transducer performs particularly well as a sensor, with recent deployment in a 4-K cryostat realizing a displacement imprecision 40 dB below that at the standard quantum limit (SQL) and an imprecision-backaction product product <60 ℏ is achieved. Our results extend the outlook for measurement-based quantum control of nanomechanical oscillators and suggest an alternative platform for functionally integrated "hybrid" quantum optomechanics.

  10. Development of alkaline fuel cells.

    Energy Technology Data Exchange (ETDEWEB)

    Hibbs, Michael R.; Jenkins, Janelle E.; Alam, Todd Michael; Janarthanan, Rajeswari; Horan, James L.; Caire, Benjamin R.; Ziegler, Zachary C.; Herring, Andrew M.; Yang, Yuan; Zuo, Xiaobing; Robson, Michael H.; Artyushkova, Kateryna; Patterson, Wendy; Atanassov, Plamen Borissov


    This project focuses on the development and demonstration of anion exchange membrane (AEM) fuel cells for portable power applications. Novel polymeric anion exchange membranes and ionomers with high chemical stabilities were prepared characterized by researchers at Sandia National Laboratories. Durable, non-precious metal catalysts were prepared by Dr. Plamen Atanassovs research group at the University of New Mexico by utilizing an aerosol-based process to prepare templated nano-structures. Dr. Andy Herrings group at the Colorado School of Mines combined all of these materials to fabricate and test membrane electrode assemblies for single cell testing in a methanol-fueled alkaline system. The highest power density achieved in this study was 54 mW/cm2 which was 90% of the project target and the highest reported power density for a direct methanol alkaline fuel cell.

  11. Laser diode side-pumped Nd:YVO4microchip laser with film-etched microcavity mirrors. (United States)

    Li, Jiyang; Niu, Yanxiong; Chen, Sanbin; Tan, Yidong


    Microchip lasers are applied as the light sources on various occasions with the end-pumping scheme. However, the vibration, the temperature drift, or the mechanical deformation of the pumping light in laser diodes in the end-pumping scheme will lead to instability in the microchip laser output, which causes errors and malfunctioning in the optic systems. In this paper, the side-pumping scheme is applied for improving the disturbance-resisting ability of the microchip laser. The transverse mode and the frequency purity of the laser output are tested. To ensure unicity in the frequency of the laser output, numerical simulations based on Fresnel-Kirchhoff diffraction theory are conducted on the parameters of the microchip laser cavity. Film-etching technique is applied to restrain the area of the film and form the microcavity mirrors. The laser output with microcavity mirrors is ensured to be in single frequency and with good beam quality, which is significant in the applications of microchip lasers as the light sources in optical systems.

  12. Enhanced green fluorescent protein in optofluidic Fabry-Perot microcavity to detect laser induced temperature changes in a bacterial culture (United States)

    Lahoz, F.; Martín, I. R.; Walo, D.; Freire, R.; Gil-Rostra, J.; Yubero, F.; Gonzalez-Elipe, A. R.


    Thermal therapy using laser sources can be used in combination with other cancer therapies to eliminate tumors. However, high precision temperature control is required to avoid damage in healthy surrounding tissues. Therefore, in order to detect laser induced temperature changes, we have used the fluorescence signal of the enhanced Green Fluorescent Protein (eGFP) over-expressed in an E. coli bacterial culture. For that purpose, the bacteria expressing eGFP are injected in a Fabry-Perot (FP) optofluidic planar microcavity. In order to locally heat the bacterial culture, external infrared or ultraviolet lasers were used. Shifts in the wavelengths of the resonant FP modes are used to determine the temperature increase as a function of the heating laser pump power. Laser induced local temperature increments up to 6-7 °C were measured. These results show a relatively easy way to measure laser induced local temperature changes using a FP microcavity and using eGFP as a molecular probe instead of external nanoparticles, which could damage/alter the cell. Therefore, we believe that this approach can be of interest for the study of thermal effects in laser induced thermal therapies.

  13. Cooling and Laser-Induced Fluorescence of Electronically-Excited He2 in a Supersonic Microcavity Plasma Jet (United States)

    Su, Rui; Mironov, Andrey; Houlahan, Thomas, Jr.; Eden, J. Gary; LaboratoryOptical Physics; Engineering Team


    Laser-induced fluorescence (LIF) resulting from transitions between different electronic states of helium dimers generated within a microcavity plasma jet was studied with rotational resolution. In particular, the d3Σu+ , e3Πg and f3Σu+ states, all having electronic energies above 24 eV, are populated by a microplasma in 4 bar of helium gas and rotationally cooled through supersonic expansion. Analysis of two dimensional maps (spectrograms) of dimer emission spectra as a function of distance from the nozzle orifice indicates collisional coupling during the expansion between the lowest rotational levels of the e3Πg , f3Σu+ states and high rotational levels (around N=11) of the d3Σu+ state (all of which are in the v = 0 vibrational state). In an attempt to verify the coupling, a scanning dye laser (centered near 596 nm) pumps the b3Πg -> f3Σu+ transition of the molecule several hundred micrometers downstream of the nozzle. As a result, the emission intensities of relevant rotational lines are observed to be enhanced. This research shows the potential of utilizing microcavity plasma jets as a tool to study and manipulate the collisional dynamics of highly-excited diatomic molecules.

  14. Analysis of longitudinal variations in North Pacific alkalinity (United States)

    Fry, C.; Tyrrell, T.; Achterberg, E. P.


    Carbon measurements in the ocean lack the coverage of physical measurements, so approximate alkalinity is predicted where data is unavailable. Surface alkalinity in the North Pacific is poorly characterised by predictive algorithms. Understanding the processes affecting alkalinity in this area can improve the equations. We investigated the causes of regional variations in alkalinity using GLODAPv2. We tested different hypotheses for the causes of three longitudinal phenomena in surface ocean values of Alk*, a tracer of calcium carbonate cycling. These phenomena are: (a) an increase in Alk* from east to west at 50°N, (b) an increase in Alk* from west to east at 30°N, and (c) a lack of a strong increase in Alk* from west to east in the equatorial upwelling area. We found that the most likely cause of higher Alk* on the western side of the subpolar North Pacific (at 50°N) is that denser isopycnals with higher Alk* lie at shallower depths on the western side than the eastern side. At 30°N, the main cause of higher Alk* on the eastern side of the basin is upwelling along the continental shelf of southwestern North America. Along the equator, our analyses suggest that the absence of a strong east-west trend is because the more intense upwelling on the eastern side of the basin does not, under normal conditions, lead to strong elevation of Alk*. However, surface Alk* is more strongly elevated in the eastern Equatorial Pacific during negative phases of the El-Nino-Southern Oscillation, probably because the upwelled water comes from greater depth at these times.

  15. Raman scattering with strongly coupled vibron-polaritons (United States)

    Strashko, Artem; Keeling, Jonathan


    Strong coupling between cavity photons and molecular vibrations can lead to the formation of vibron-polaritons. In a recent experiment with PVAc molecules in a metal-metal microcavity [Shalabney et al., Angew. Chem., Int. Ed. 54, 7971 (2015), 10.1002/anie.201502979], such a coupling was observed to enhance the Raman scattering probability by several orders of magnitude. Inspired by this, we theoretically analyze the effect of strong photon-vibron coupling on the Raman scattering amplitude of organic molecules. This problem has recently been addressed by del Pino, Feist, and Garcia-Vidal [J. Phys. Chem. C 119, 29132 (2015), 10.1021/acs.jpcc.5b11654] using exact numerics for a small number of molecules. In this paper we derive compact analytic results for any number of molecules, also including the ultrastrong-coupling regime. Our calculations predict a division of the Raman signal into upper and lower polariton modes, with some enhancement to the lower polariton Raman amplitude due to the mode softening under strong coupling.

  16. Ocean Acidification: Coccolithophore's Light Controlled Effect on Alkalinity (United States)

    Dobbins, W.


    Coccolithophorids, which play a significant role in the flux of calcite and organic carbon from the photic region to deeper pelagic and benthic zones, are potentially far more useful than siliceous phytoplankton for ocean fertilization projects designed to sequester CO2. However, the production of H+ ions during calcification (HCO3 + Ca+ —> CaCO3 + H+) has resulted in localized acidification around coccolithophore blooms. It has been hypothesized that under the correct light conditions photosynthesis could proceed at a rate such that CO2 is removed in amounts equimolar or greater than the H+ produced by calcification, allowing stable or increasing alkalinity despite ongoing calcification. Previously, this effect had not been demonstrated under laboratory conditions. Fifteen Emiliania huxleyi cultures were separated into equal groups with each receiving: 0, 6, 12, 18, or 24 hours of light each day for 24 days. Daily pH, cell density, and temperature measurements revealed a strong positive correlation between light exposure and pH, and no significant decline in pH in any of the cultures. Alkalinity increases were temperature independent and not strongly correlated with cell density, implying photosynthetic removal of carbon dioxide as the root cause. The average pH across living cultures increased from 7.9 to 8.3 over the first week and changed little for the reminder of the 24-day period. The results demonstrate coccolithophorids can increase alkalinity across a broad range of cell densities, despite the acidification inherent to the calcification process. If the light-alkalinity effect reported here proves scalable to larger cultures, Emiliania huxleyi are a strong candidate for carbon sequestration via targeted ocean fertilization.

  17. Histochemistry of placental alkaline phosphatase in preeclampsia


    Shevade, Sapna Prashant; Arole, Vasanti; Paranjape, Vaishali Mohan; Bharambe, Vaishaly Kishore


    Objectives: Placental alkaline phosphatase (PALP) is synthesized in placenta and increases with gestational age. Alkaline phosphatase supports pregnancy and could play an essential role in nutrient supply and growth of the fetus. Preeclampsia is a systemic disorder which affects 5 to 7 percent of women worldwide and is a major cause for maternal and neonatal morbidity and mortality. As it has a major role in fetal growth, nutrition and defense mechanism study of alkaline phosphatase enzymatic...

  18. Alkaline Electrochemical Capacitor and Electrode Fabrication

    National Research Council Canada - National Science Library

    Finello, D


    .... The subject low cost alkaline electrochemical capacitor designs are based upon titanium nitride electrodes which exhibit 125 mF/sq cm surface capacitance density and remarkable electrochemical...

  19. Corrosion of copper in alkaline chloride environments

    International Nuclear Information System (INIS)

    King, F.


    The available literature information on the corrosion and electrochemical behaviour of copper in alkaline environments has been reviewed. The purpose of the review was to assess the impact of an alkaline plume from cementitious material on the corrosion behaviour of a copper canister in an SKB-3 type repository. The effect of the evolution of the environmental conditions within the repository have been considered, including the effects of temperature, redox conditions, pore-water salinity and pH. If the pore-water pH increases prior to the establishment of anoxic conditions, the canister surface will passivate as the pore-water pH exceeds a value of ∼ pH 9. Passivation will result from the formation of a duplex Cu 2 O/Cu(OH) 2 film. The corrosion potential will be determined by the equilibrium potential for the Cu 2 O/Cu(OH) 2 couple under oxic conditions, or by the Cu/Cu 2 O redox couple under anoxic conditions (in the absence of sulphide). Pitting corrosion is only likely to occur early in the evolution of the repository environment, whilst the canister is still relatively cool ( 2 available to support localised corrosion, and prior to the increase in pore-water pH and salinity. The subsequent increase in canister surface temperature, pore-water pH and salinity, and decrease in O 2 will make pit initiation less likely, although the canister will remain passive provided the pore-water pH is maintained above pH 9. The higher the pore-water pH, the more strongly the canister is passivated and the less likely the surface is to undergo localised attack. If the pore-water salinity increases prior to the increase in pH, there could be a period of active canister corrosion before passivation occurs.Under these circumstances, the corrosion potential will be a true mixed potential, determine by the relative kinetics of Cu dissolution as CuCl 2 - and of the reduction of O 2 . The development of anoxic conditions and an increase in pore-water sulphide concentration will

  20. Progress of research on the influence of alkaline cation and alkaline solution on bentonite properties

    International Nuclear Information System (INIS)

    Ye Weimin; Zheng Zhenji; Chen Bao; Chen Yonggui


    Based on the previous laboratory studies and numerical simulation on bentonite in alkaline environments, the effects of alkaline cation and alkaline solution on mineral composition, microstructure, swelling capacity and hydraulic properties of bentonite are emphasized in this paper, temperature, pH values and concentration are discussed as main affecting factors. When bentonite is exposed to alkaline cation or alkaline solution, microstructure of bentonite will be changed due to the dissolution of montmorillonite and the formation of secondary minerals, which results in the decrease of swelling pressure. The amount of the reduction of swelling pressure depends on the concentration of alkaline solution. Temperature, polyvalent cation, salinity and concentration are the main factors affecting hydraulic properties of bentonite under alkaline conditions. Therefore, future research should focus on the mechanism of coupling effects of weak alkaline solutions on the mineral composition, microstructure, swelling capacity and hydraulic properties of bentonite under different temperatures and different pH values. (authors)

  1. Alkaline and alkaline earth metal phosphate halides and phosphors (United States)

    Lyons, Robert Joseph; Setlur, Anant Achyut; Cleaver, Robert John


    Compounds, phosphor materials and apparatus related to nacaphite family of materials are presented. Potassium and rubidium based nacaphite family compounds and phosphors designed by doping divalent rare earth elements in the sites of alkaline earth metals in the nacaphite material families are descried. An apparatus comprising the phosphors based on the nacaphite family materials are presented herein. The compounds presented is of formula A.sub.2B.sub.1-yR.sub.yPO.sub.4X where the elements A, B, R, X and suffix y are defined such that A is potassium, rubidium, or a combination of potassium and rubidium and B is calcium, strontium, barium, or a combination of any of calcium, strontium and barium. X is fluorine, chlorine, or a combination of fluorine and chlorine, R is europium, samarium, ytterbium, or a combination of any of europium, samarium, and ytterbium, and y ranges from 0 to about 0.1.

  2. Scalable quantum computing based on stationary spin qubits in coupled quantum dots inside double-sided optical microcavities. (United States)

    Wei, Hai-Rui; Deng, Fu-Guo


    Quantum logic gates are the key elements in quantum computing. Here we investigate the possibility of achieving a scalable and compact quantum computing based on stationary electron-spin qubits, by using the giant optical circular birefringence induced by quantum-dot spins in double-sided optical microcavities as a result of cavity quantum electrodynamics. We design the compact quantum circuits for implementing universal and deterministic quantum gates for electron-spin systems, including the two-qubit CNOT gate and the three-qubit Toffoli gate. They are compact and economic, and they do not require additional electron-spin qubits. Moreover, our devices have good scalability and are attractive as they both are based on solid-state quantum systems and the qubits are stationary. They are feasible with the current experimental technology, and both high fidelity and high efficiency can be achieved when the ratio of the side leakage to the cavity decay is low.

  3. Optical limiting performance of a GaAs/AlAs heterostructure microcavity in the near-infrared. (United States)

    Ryzhov, A A


    A multilayer GaAs/AlAs heterostructure forming a Fabry-Perot microcavity with a narrow resonance at 1.1 μm was produced by molecular-beam epitaxy. Under nanosecond pulsed laser radiation, a blueshift of the resonant line, associated with a photo-induced negative change in refractive index in GaAs, was experimentally registered by using an optical parametric oscillator. The spectral shift was accompanied by a reduction in peak transmittance, associated with nonlinear intracavity absorption. Such a cavity can be used as an optical limiter at the resonant wavelength when both the spectral shift and the transmittance reduction contribute to the limiting effect. An exceptionally low limiting threshold of about 1  mJ/cm 2 was observed in the experiment.

  4. Homoepitaxial nonpolar (10-10) ZnO/ZnMgO monolithic microcavities: Towards reduced photonic disorder

    Energy Technology Data Exchange (ETDEWEB)

    Zuniga-Perez, J., E-mail:; Kappei, L.; Deparis, C.; Chenot, S.; Leroux, M. [CRHEA-CNRS, Rue Bernard Gregory, 06560 Valbonne (France); Reveret, F.; Jamadi, O.; Leymarie, J. [Clermont Université, Institut Pascal (IP), BP 10448, F-63000 Clermont-Ferrand (France); CNRS, UMR 6602, IP, F-63171 Aubière (France); Grundmann, M. [CRHEA-CNRS, Rue Bernard Gregory, 06560 Valbonne (France); Institut für Experimentelle Physik II, Fakultät für Physik und Geowissenschaften, Universität Leipzig, Linnestr. 5, 04103 Leipzig (Germany); Prado, E. de [CRHEA-CNRS, Rue Bernard Gregory, 06560 Valbonne (France); Departamento de Física Aplicada y Electromagnetismo, Universitat de Valencia, c/Dr Moliner 50, Burjassot, Valencia 46100 (Spain)


    Nonpolar ZnO/ZnMgO-based optical microcavities have been grown on (10-10) m-plane ZnO substrates by plasma-assisted molecular beam epitaxy. Reflectivity measurements indicate an exponential increase of the cavity quality factor with the number of layers in the distributed Bragg reflectors. Most importantly, microreflectivity spectra recorded with a spot size in the order of 2 μm show a negligible photonic disorder (well below 1 meV), leading to local quality factors equivalent to those obtained by macroreflectivity. The anisotropic character of the nonpolar heterostructures manifests itself both in the surface features, elongated parallel to the in-plane c direction, and in the optical spectra, with two cavity modes being observed at different energies for orthogonal polarizations.

  5. Analysis of ultra-high sensitivity configuration in chip-integrated photonic crystal microcavity bio-sensors

    Energy Technology Data Exchange (ETDEWEB)

    Chakravarty, Swapnajit, E-mail:; Hosseini, Amir; Xu, Xiaochuan [Omega Optics, Inc., Austin, Texas 78757 (United States); Zhu, Liang; Zou, Yi [Department of Electrical and Computer Engineering, University of Texas at Austin, Austin, Texas 78758 (United States); Chen, Ray T., E-mail: [Omega Optics, Inc., Austin, Texas 78757 (United States); Department of Electrical and Computer Engineering, University of Texas at Austin, Austin, Texas 78758 (United States)


    We analyze the contributions of quality factor, fill fraction, and group index of chip-integrated resonance microcavity devices, to the detection limit for bulk chemical sensing and the minimum detectable biomolecule concentration in biosensing. We analyze the contributions from analyte absorbance, as well as from temperature and spectral noise. Slow light in two-dimensional photonic crystals provide opportunities for significant reduction of the detection limit below 1 × 10{sup −7} RIU (refractive index unit) which can enable highly sensitive sensors in diverse application areas. We demonstrate experimentally detected concentration of 1 fM (67 fg/ml) for the binding between biotin and avidin, the lowest reported till date.

  6. Alkaline azide mutagenicity in cowpea

    International Nuclear Information System (INIS)

    Mahna, S.K.; Bhargava, Anubha; Mohan, Lalit


    Sodium azide is known as a potent mutagen in cereals and legumes. It is very effective in acidic medium in barley. Here an attempt is made to measure the effectiveness of sodium azide in alkaline medium (pH 7.4) on cowpea (Vigna unguiculata (L.) Walp., variety FS-68). Seeds pre-soaked in distilled water for 5 hours were treated with different concentrations (10 -6 , 10 -5 , 10 -4 and 10 -3 M) of sodium azide (NaN 3 ) for 4 hours at 28± 2 deg. C. Bottles were intermittently shaken, then the seeds were thoroughly washed in running tap water and subsequently planted in pots. The treatment caused significant biological damage such as reduction in seed germination, length of root and shoot, number of nodules and pods per plant and morphological leaf variations. Morphological, as well as chlorophyll mutants, were detected in M 2

  7. catalysed oxidation of atenolol by alkaline permanganate

    Indian Academy of Sciences (India)


    Abstract. Kinetics of ruthenium (III) catalyzed oxidation of atenolol by permanganate in alkaline medium at constant ionic strength of 0⋅30 mol dm3 has been studied spectrophotometrically using a rapid kinetic accessory. Reaction between permanganate and atenolol in alkaline medium exhibits 1 : 8 stoichiometry.

  8. Increased liver alkaline phosphatase and aminotransferase ...

    African Journals Online (AJOL)

    The effect of daily, oral administration of ethanolic extract of Khaya senegalensis stem bark (2mg/kg body weight) for 18days on the alkaline phosphatase, aspartate and alanine aminotransferase activities of rat liver and serum were investigated. Compared with the control, the activities of liver alkaline phosphatase (ALP), ...

  9. Alkaline Phosphatases From Camel Small Intestine | Fahmy ...

    African Journals Online (AJOL)

    Camel intestinal alkaline phosphatase have been purified and characterized. The purification was carried out by chromatography on DEAE-cellulose. Five intestinal alkaline phosphatase isoenzymes (IAP1 to IAP5) were obtained. IAP2 and IAP5 with the highest activity levels were purified to homogeneity by Sephacryl ...

  10. Handbook of Indigenous Foods Involving Alkaline Fermentation

    NARCIS (Netherlands)

    Sarkar, P.K.; Nout, M.J.R.


    This book details the basic approaches of alkaline fermentation, provides a brief history, and offers an overview of the subject. The book discusses the diversity of indigenous fermented foods involving an alkaline reaction, as well as the taxonomy, ecology, physiology, and genetics of predominant

  11. Alkaline Phosphatase, Soluble Extracellular Adenine Nucleotides, and Adenosine Production after Infant Cardiopulmonary Bypass. (United States)

    Davidson, Jesse A; Urban, Tracy; Tong, Suhong; Twite, Mark; Woodruff, Alan; Wischmeyer, Paul E; Klawitter, Jelena


    Decreased alkaline phosphatase activity after infant cardiac surgery is associated with increased post-operative cardiovascular support requirements. In adults undergoing coronary artery bypass grafting, alkaline phosphatase infusion may reduce inflammation. Mechanisms underlying these effects have not been explored but may include decreased conversion of extracellular adenine nucleotides to adenosine. 1) Evaluate the association between alkaline phosphatase activity and serum conversion of adenosine monophosphate to adenosine after infant cardiac surgery; 2) assess if inhibition/supplementation of serum alkaline phosphatase modulates this conversion. Pre/post-bypass serum samples were obtained from 75 infants alkaline phosphatase and CD73. Low and high concentration 13C5-adenosine monophosphate (simulating normal/stress concentrations) were used. Effects of alkaline phosphatase supplementation on adenosine monophosphate clearance were also assessed. Changes in serum alkaline phosphatase activity were strongly correlated with changes in 13C5-adenosine production with or without CD73 inhibition (r = 0.83; palkaline phosphatase activity (≤80 U/L) generated significantly less 13C5-adenosine, particularly in the presence of high concentration 13C5-adenosine monophosphate (10.4μmol/L vs 12.9μmol/L; p = 0.0004). Inhibition of alkaline phosphatase led to a marked decrease in 13C5-adenosine production (11.9μmol/L vs 2.7μmol/L; palkaline phosphatase or high dose bovine intestinal alkaline phosphatase doubled 13C5-adenosine monophosphate conversion to 13C5-adenosine (pAlkaline phosphatase represents the primary serum ectonucleotidase after infant cardiac surgery and low post-operative alkaline phosphatase activity leads to impaired capacity to clear adenosine monophosphate. AP supplementation improves serum clearance of adenosine monophosphate to adenosine. These findings represent a potential therapeutic mechanism for alkaline phosphatase infusion during cardiac

  12. Rb-Sr age of the Sivamalai alkaline complex, Tamil Nadu

    International Nuclear Information System (INIS)

    Subba Rao, T.V.; Narayana, B.L.; Gopalan, K.


    The Sivamalai alkaline complex comprises ferro-, pyroxene- hornblende-and nepheline-syenites. Field relations show that the nepheline syenites followed the emplacement of non-feldspathoidal syenites. Mineralogical data on the syenite suite have been reviewed. The Sivamalai alkaline rocks are not strongly enriched in rare-earth elements like most miaskites. Rb-Sr isotopic analyses of a suite of six samples from the various members of the complex define an isochron corresponding to an age of 623 ± 21 Ma (2σ) and initial Sr ratio of 0.70376 ± 14 (2σ). This is consistent with a model of fractional crystallization of a parent magma derived from an upper mantle source with apparently no isotopic evidence for more than one magma source for the complex. The Sivamalai alkaline complex represents a Pan-African alkaline magmatic event in the southern granulite terrane of peninsular India. (author). 26 refs., 4 figs., 4 tabs

  13. Fabry-Pérot microcavity modes observed in the micro-photoluminescence spectra of the single nanowire with InGaAs/GaAs heterostructure. (United States)

    Yang, Lin; Motohisa, Junichi; Fukui, Takashi; Jia, Lian Xi; Zhang, Lei; Geng, Ming Min; Chen, Pin; Liu, Yu Liang


    We report on the fabrication of the nanowires with InGaAs/GaAs heterostructures on the GaAs(111)B substrate using selective-area metal organic vapor phase epitaxy. Fabry-Pérot microcavity modes were observed in the nanowires with perfect end facets dispersed onto the silicon substrate and not observed in the free-standing nanowires. We find that the calculated group refractive indices only considering the material dispersion do not agree with the experimentally determined values although this method was used by some researchers. The calculated group refractive indices considering both the material dispersion and the waveguide dispersion agree with the experimentally determined values well. We also find that Fabry-Pérot microcavity modes are not observable in the nanowires with the width less than about 180 nm, which is mainly caused by their poor reflectivity at the end facets due to their weak confinement to the optical field.

  14. Alkaline Phosphatase: MedlinePlus Lab Test Information (United States)

    ... this page: Alkaline Phosphatase To use the sharing features on this page, please enable JavaScript. What is an Alkaline Phosphatase Test? An alkaline phosphatase (ALP) test measures ...

  15. Testing strong interaction theories

    International Nuclear Information System (INIS)

    Ellis, J.


    The author discusses possible tests of the current theories of the strong interaction, in particular, quantum chromodynamics. High energy e + e - interactions should provide an excellent means of studying the strong force. (W.D.L.)

  16. Multisystemic functions of alkaline phosphatases. (United States)

    Buchet, René; Millán, José Luis; Magne, David


    Human and mouse alkaline phosphatases (AP) are encoded by a multigene family expressed ubiquitously in multiple tissues. Gene knockout (KO) findings have helped define some of the precise exocytic functions of individual isozymes in bone, teeth, the central nervous system, and in the gut. For instance, deficiency in tissue-nonspecific alkaline phosphatase (TNAP) in mice (Alpl (-/-) mice) and humans leads to hypophosphatasia (HPP), an inborn error of metabolism characterized by epileptic seizures in the most severe cases, caused by abnormal metabolism of pyridoxal-5'-phosphate (the predominant form of vitamin B6) and by hypomineralization of the skeleton and teeth featuring rickets and early loss of teeth in children or osteomalacia and dental problems in adults caused by accumulation of inorganic pyrophosphate (PPi). Enzyme replacement therapy with mineral-targeting TNAP prevented all the manifestations of HPP in mice, and clinical trials with this protein therapeutic are showing promising results in rescuing life-threatening HPP in infants. Conversely, TNAP induction in the vasculature during generalized arterial calcification of infancy (GACI), type II diabetes, obesity, and aging can cause medial vascular calcification. TNAP inhibitors, discussed extensively in this book, are in development to prevent pathological arterial calcification. The brush border enzyme intestinal alkaline phosphatase (IAP) plays an important role in fatty acid (FA) absorption, in protecting gut barrier function, and in determining the composition of the gut microbiota via its ability to dephosphorylate lipopolysaccharide (LPS). Knockout mice (Akp3 (-/-)) deficient in duodenal-specific IAP (dIAP) become obese, and develop hyperlipidemia and hepatic steatosis when fed a high-fat diet (HFD). These changes are accompanied by upregulation in the jejunal-ileal expression of the Akp6 IAP isozyme (global IAP, or gIAP) and concomitant upregulation of FAT/CD36, a phosphorylated fatty acid

  17. Alkaline pH homeostasis in bacteria: new insights. (United States)

    Padan, Etana; Bibi, Eitan; Ito, Masahiro; Krulwich, Terry A


    The capacity of bacteria to survive and grow at alkaline pH values is of widespread importance in the epidemiology of pathogenic bacteria, in remediation and industrial settings, as well as in marine, plant-associated and extremely alkaline ecological niches. Alkali-tolerance and alkaliphily, in turn, strongly depend upon mechanisms for alkaline pH homeostasis, as shown in pH shift experiments and growth experiments in chemostats at different external pH values. Transcriptome and proteome analyses have recently complemented physiological and genetic studies, revealing numerous adaptations that contribute to alkaline pH homeostasis. These include elevated levels of transporters and enzymes that promote proton capture and retention (e.g., the ATP synthase and monovalent cation/proton antiporters), metabolic changes that lead to increased acid production, and changes in the cell surface layers that contribute to cytoplasmic proton retention. Targeted studies over the past decade have followed up the long-recognized importance of monovalent cations in active pH homeostasis. These studies show the centrality of monovalent cation/proton antiporters in this process while microbial genomics provides information about the constellation of such antiporters in individual strains. A comprehensive phylogenetic analysis of both eukaryotic and prokaryotic genome databases has identified orthologs from bacteria to humans that allow better understanding of the specific functions and physiological roles of the antiporters. Detailed information about the properties of multiple antiporters in individual strains is starting to explain how specific monovalent cation/proton antiporters play dominant roles in alkaline pH homeostasis in cells that have several additional antiporters catalyzing ostensibly similar reactions. New insights into the pH-dependent Na(+)/H(+) antiporter NhaA that plays an important role in Escherichia coli have recently emerged from the determination of the

  18. Alkaline sorbent injection for mercury control (United States)

    Madden, Deborah A.; Holmes, Michael J.


    A mercury removal system for removing mercury from combustion flue gases is provided in which alkaline sorbents at generally extremely low stoichiometric molar ratios of alkaline earth or an alkali metal to sulfur of less than 1.0 are injected into a power plant system at one or more locations to remove at least between about 40% and 60% of the mercury content from combustion flue gases. Small amounts of alkaline sorbents are injected into the flue gas stream at a relatively low rate. A particulate filter is used to remove mercury-containing particles downstream of each injection point used in the power plant system.

  19. Alkaline rocks and the occurrence of uranium

    International Nuclear Information System (INIS)

    Hambleton-Jones, B.B.; Toens, P.D.


    Many alkaline complexes contain uranium and other minerals in low concentrations and are regarded as constituting valuable potential reserves. Certain complex metallurgical problems, however, remain to be solved. Alkaline rocks occur in a number of forms and environments and it is noted that they are generated during periods of geological quiescence emplaced mainly in stable aseismic areas. Many occur along the extensions of oceanic transform faults beneath the continental crust and the application of this concept to areas not currently known to host alkaline complexes may prove useful in identifying potential target areas for prospecting operations [af

  20. Geochemical features of the Cretaceous alkaline volcanics in the area of Morado hill, Jachal town, San Juan, Argentina

    International Nuclear Information System (INIS)

    Perez, L.


    This paper is about the alkaline volcanic rocks that crop out at the Morado hill located in the southern end of the Mogna ranges, which are part of the Eastern border of the pre mountain in the San Juan province, Argentina.The petrography and geochemistry study of the alkaline volcanics has allowed to classify them as tephrite basanite or basanite nephelinite, with strong alkaline chemical affinity, showing a characteristic composition of within plate geochemistry environment. The radimetric analysis, K-Ar data, has shown an average 90 ∓ 8 m.y. age for this rocks, (Cingolani et al. 1984) pointing out the Upper Cretaceous (lower section) stratigraphical position for the suite. The discussion of the results makes conspicuous the relationships of these alkaline rocks with others of the central and northwestern regions of the country that allowed to establish an alkaline petrographic province

  1. Alkalinity in oil field waters - what alkalinity is and how it is measured

    International Nuclear Information System (INIS)

    Kaasa, B.; Oestvold, T.


    The alkalinity is an important parameter in the description of pH-behaviour, buffer capacity and scaling potentials in oil field waters. Although the alkalinity is widely used, it seems to be considerable confusion in connection with the concept. It is often used incorrectly and different authors define the concept in different ways. Several different methods for the determination of alkalinity can be found in the literature. This paper discusses the definition of alkalinity and how to use alkalinity in oil field waters to obtain data of importance for scale and pH predictions. There is also shown how a simple titration of oil field waters can give both the alkalinity and the content of organic acids in these waters. It is obvious from these findings that most of the methods used to day may give considerable errors when applied to oil field waters with high contents of organic acids. 8 refs., 8 figs., 5 tabs

  2. Alkaline Electrochemical Capacitor and Electrode Fabrication

    National Research Council Canada - National Science Library

    Finello, D


    .... With energy density in excess of 300 mJ/cc and the potential to exceed a power density of 100 W/cc, the alkaline electrochemical capacitor represents a significant advancement in technology for high power energy storage.

  3. Qualitative Carbohydrate Analysis using Alkaline Potassium ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 21; Issue 3. Qualitative Carbohydrate Analysis using Alkaline Potassium Ferricyanide. Sangeeta Pandita Saral Baweja. Classroom Volume 21 Issue 3 March 2016 pp 285-288 ...

  4. Toxicity of alkalinity to Hyalella azteca (United States)

    Lasier, P.J.; Winger, P.V.; Reinert, R.E.


    Toxicity testing and chemical analyses of sediment pore water have been suggested for use in sediment quality assessments and sediment toxicity identification evaluations. However, caution should be exercised in interpreting pore-water chemistry and toxicity due to inherent chemical characteristics and confounding relationships. High concentrations of alkalinity, which are typical of sediment pore waters from many regions, have been shown to be toxic to test animals. A series of tests were conducted to assess the significance of elevated alkalinity concentrations to Hyalella azteca, an amphipod commonly used for sediment and pore-water toxicity testing. Toxicity tests with 14-d old and 7-d old animals were conducted in serial dilutions of sodium bicarbonate (NaHCO3) solutions producing alkalinities ranging between 250 to 2000 mg/L as CaCO3. A sodium chloride (NaCl) toxicity test was also conducted to verify that toxicity was due to bicarbonate and not sodium. Alkalinity was toxic at concentrations frequently encountered in sediment pore water. There was also a significant difference in the toxicity of alkalinity between 14-d old and 7-d old animals. The average 96-h LC50 for alkalinity was 1212 mg/L (as CaCO3) for 14-d old animals and 662 mg/L for the younger animals. Sodium was not toxic at levels present in the NaHCO3 toxicity tests. Alkalinity should be routinely measured in pore-water toxicity tests, and interpretation of toxicity should consider alkalinity concentration and test-organism tolerance.

  5. Hybrid Alkaline Cements: Bentonite-Opc Binders

    Directory of Open Access Journals (Sweden)

    Ines Garcia-Lodeiro


    Full Text Available Moderately alkaline activators can be used to formulate cementitious binders with a high Supplemetary Cementitious Materials (SCMs and a low portland cement content (hybrid alkaline cements. This study aimed to prepare hybrid alkaline cements containing large percentages of dehydroxylated bentonite (BT and small Portland cement (OPC fractions, with 5% Na2SO4 as a solid alkaline activator. The hydration kinetics of the pastes hydrated in water in the presence and absence of the solid activator were assessed by isothermal conduction calorimetry, whilst the reaction products were characterised with X-Ray Powder Diffraction (XRD and Fourier-transform Infrared Spectroscopy (FTIR. The presence of the alkaline activator hastened OPC and BT/OPC hydration: more heat of hydration was released, favouring greater initial bentonite reactivity. The portlandite forming during cement hydration reacted readily with the Na2SO4, raising medium alkalinity and enhancing bentonite dissolution and with it reaction product precipitation (primarily (N,C-A-S-H-like gels that co-exist with C-S-H- or C-A-S-H-like gels. The presence of sulfate ions favoured the formation of AFm-like phases. Preceding aspects accelerated the hydration reactions, with the formation of more reaction product and matrix densification. As a result, the 28 days Na2SO4 activated systems developed greater mechanical strength than the water-hydrated systems, with the 60% BT/40% OPC blends exhibiting higher compressive strength than the 100% OPC pastes.

  6. 2nd Generation alkaline electrolysis. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Yde, L. [Aarhus Univ. Business and Social Science - Centre for Energy Technologies (CET), Aarhus (Denmark); Kjartansdottir, C.K. [Technical Univ. of Denmark. DTU Mechanical Engineering, Kgs. Lyngby (Denmark); Allebrod, F. [Technical Univ. of Denmark. DTU Energy Conversion, DTU Risoe Campus, Roskilde (Denmark)] [and others


    conditions and the degradation mechanism was examined. One of the strong visions for the 2{sup nd} generation electrolyser concept has been to develop a modular system with several standardized components. The following modules have been designed: 1) Electrolyser module; 2) Deoxer Module; 3) Dryer Module; 4) Water Treatment Module; 5) Power supply and Control unit; 6) Rack mount. The developed 2{sup nd} generation rack-mounted alkaline electrolyser system has been installed and demonstrated for 18 month in a college (H2College) with 66 apartments. A number of measurements were performed on the system installed in H2College. No measurements on the overall system efficiency were conducted. However measurement on the stack showed a stack efficiency of 86.5% at a current density of 177mA/cm{sup 2} and a temperature of 74.4 deg. C at the hydrogen outlet. The system is estimated to have run roughly 2000h during the demonstration period. The demonstration of the 2{sup nd} generation alkaline electrolyser is considered a success for several reasons. While not all technical goals were reached, the research and development in the project have resulted in some very good solutions for most of the challenges in high pressure alkaline electrolysis. The concept of a rack mounted electrolyser was proven viable, and all critical aspects of the modularisation have been covered. (LN)

  7. 21 CFR 864.7660 - Leukocyte alkaline phosphatase test. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Leukocyte alkaline phosphatase test. 864.7660... Leukocyte alkaline phosphatase test. (a) Identification. A leukocyte alkaline phosphatase test is a device used to identify the enzyme leukocyte alkaline phosphatase in neutrophilic granulocytes (granular...

  8. Improved electrodes and gas impurity investigations on alkaline electrolysers

    DEFF Research Database (Denmark)

    Reissner, R.; Schiller, G.; Knoeri, T.

    Alkaline water electrolysis for hydrogenproduction is a well-established techniquebut some technological issues regarding thecoupling of alkaline water electrolysis andRenewable Energy Sources (RES) remain tobe improved.......Alkaline water electrolysis for hydrogenproduction is a well-established techniquebut some technological issues regarding thecoupling of alkaline water electrolysis andRenewable Energy Sources (RES) remain tobe improved....

  9. Pseudomonas syringae evades host immunity by degrading flagellin monomers with alkaline protease AprA

    NARCIS (Netherlands)

    Pel, Michiel J C; van Dijken, Anja J H; Bardoel, Bart W; Seidl, Michael F; van der Ent, Sjoerd; van Strijp, Jos A G; Pieterse, Corné M J

    Bacterial flagellin molecules are strong inducers of innate immune responses in both mammals and plants. The opportunistic pathogen Pseudomonas aeruginosa secretes an alkaline protease called AprA that degrades flagellin monomers. Here, we show that AprA is widespread among a wide variety of

  10. Pseudomonas syringae evades host Immunity by degrading flagellin monomers with alkaline protease AprA

    NARCIS (Netherlands)

    Pel, M.J.C.; Van Dijken, A.J.H.; Bardoel, B.W.; Seidl, M.F; Van der Ent, S.; Van Strijp, J.A.G.


    Bacterial flagellin molecules are strong inducers of innate immune responses in both mammals and plants. The opportunistic pathogen Pseudomonas aeruginosa secretes an alkaline protease called AprA that degrades flagellin monomers. Here, we show that AprA is widespread among a wide variety of

  11. Measurement of pH, alkalinity and acidity in ultra-soft waters

    African Journals Online (AJOL)



    Oct 4, 2001 ... A blend composed of the raw water, sodium chloride (to increase conductivity), and standard bicarbonate (to increase buffering capacity) was titrated with standard strong acid in two pH regions: 6.3 pH < 4.0. In both methods, total alkalinity was determined using the latter set of points, ...

  12. Silica-poor, mafic alkaline lavas from ocean islands and continents

    Indian Academy of Sciences (India)

    Strongly silica-poor (ne-normative), mafic alkaline lavas generally represented by olivine nephelinites, nephelinites, melilitites, and olivine melilitites have erupted at various locations during Earth's history. On the basis of bulk-rock Mg#, high concentrations of Na2O, TiO2, and K2O, and trace element geochemistry, it has ...


    Directory of Open Access Journals (Sweden)



    Full Text Available We demonstrate the feasibility of simultaneous multi-probe detection for an optical-resolution photoacoustic microscopy (OR-PAM system. OR-PAM has elicited the attention of biomedical imaging researchers because of its optical absorption contrast and high spatial resolution with great imaging depth. OR-PAM allows label-free and noninvasive imaging by maximizing the optical absorption of endogenous biomolecules. However, given the inadequate absorption of some biomolecules, detection sensitivity at the same incident intensity requires improvement. In this study, a modulated continuous wave with power density less than 3 mW/cm2 (1/4 of the ANSI safety limit excited the weak photoacoustic (PA signals of biological cells. A microcavity transducer is developed based on the bulk modulus of gas five orders of magnitude lower than that of solid; air pressure variation is inversely proportional to cavity volume at the same temperature increase. Considering that a PA wave expands in various directions, detecting PA signals from different positions and adding them together can increase detection sensitivity and signal-to-noise ratio. Therefore, we employ four detectors to acquire tiny PA signals simultaneously. Experimental results show that the developed OR-PAM system allows the label-free imaging of cells with weak optical absorption.

  14. Metal adsorbent for alkaline etching aqua solutions of Si wafer

    International Nuclear Information System (INIS)

    Tamada, Masao; Ueki, Yuji; Seko, Noriaki; Takeda, Toshihide; Kawano, Shin-ichi


    High performance adsorbent is expected to be synthesized for the removal of Ni and Cu ions from strong alkaline solution used in the surface etching process of Si wafer. Fibrous adsorbent was synthesized by radiation-induce emulsion graft polymerization onto polyethylene nonwoven fabric and subsequent amination. The reaction condition was optimized using 30 L reaction vessel and nonwoven fabric, 0.3 m width and 18 m long. The resulting fibrous adsorbent was evaluated by 48 wt% NaOH and KOH contaminated with Ni and Cu ions, respectively. The concentration levels of Ni and Cu ions was reduced to less than 1 μg/kg (ppb) at the flow rate of 10 h −1 in space velocity. The life of adsorbent was 30 times higher than that of the commercialized resin. This novel adsorbent was commercialized as METOLATE ® since the ability of adsorption is remarkably higher than that of commercial resin used practically in Si wafer processing. - Highlights: ► Adsorbent was synthesized by radiation-induced emulsion graft polymerization. ► Degree of grafting reached 120% at the pre-irradiation of 50 kGy. ► The resulting adsorbent removed Ni and Cu ion in strong alkaline solution. ► Adsorbent was commercialized for filter of Si wafer etchant.

  15. Strongly Correlated Topological Insulators (United States)


    Strongly Correlated Topological Insulators In the past year, the grant was used for work in the field of topological phases, with emphasis on finding...surface of topological insulators. In the past 3 years, we have started a new direction, that of fractional topological insulators. These are which a topologically nontrivial quasi-flat band is fractionally filled and then subject to strong interactions. The views, opinions and/or

  16. Strong Cosmic Censorship (United States)

    Isenberg, James


    The Hawking-Penrose theorems tell us that solutions of Einstein's equations are generally singular, in the sense of the incompleteness of causal geodesics (the paths of physical observers). These singularities might be marked by the blowup of curvature and therefore crushing tidal forces, or by the breakdown of physical determinism. Penrose has conjectured (in his `Strong Cosmic Censorship Conjecture`) that it is generically unbounded curvature that causes singularities, rather than causal breakdown. The verification that ``AVTD behavior'' (marked by the domination of time derivatives over space derivatives) is generically present in a family of solutions has proven to be a useful tool for studying model versions of Strong Cosmic Censorship in that family. I discuss some of the history of Strong Cosmic Censorship, and then discuss what is known about AVTD behavior and Strong Cosmic Censorship in families of solutions defined by varying degrees of isometry, and discuss recent results which we believe will extend this knowledge and provide new support for Strong Cosmic Censorship. I also comment on some of the recent work on ``Weak Null Singularities'', and how this relates to Strong Cosmic Censorship.

  17. Prophylactic treatment with alkaline phosphatase in cardiac surgery induces endogenous alkaline phosphatase release

    NARCIS (Netherlands)

    Kats, Suzanne; Brands, Ruud; Hamad, Mohamed A. Soliman; Seinen, Willem; Schamhorst, Volkher; Wulkan, Raymond W.; Schoenberger, Jacques P.; van Oeveren, Wim

    Introduction: Laboratory and clinical data have implicated endotoxin as an important factor in the inflammatory response to cardiopulmonary bypass. We assessed the effects of the administration of bovine intestinal alkaline phosphatase (bIAP), an endotoxin detoxifier, on alkaline phosphatase levels

  18. The stability of polyaniline in strongly alkaline and acidic aqueous media

    Czech Academy of Sciences Publication Activity Database

    Brožová, Libuše; Holler, Petr; Kovářová, Jana; Stejskal, Jaroslav; Trchová, Miroslava


    Roč. 93, č. 3 (2008), s. 592-600 ISSN 0141-3910 R&D Projects: GA MPO FT-TA2/098; GA ČR GA203/08/0686 Institutional research plan: CEZ:AV0Z40500505 Keywords : polyaniline * stability * conducting polymer Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.320, year: 2008

  19. Oxidation of arsenite by molecular oxygen in strong alkaline solution under γ-radiation

    International Nuclear Information System (INIS)

    Burkitbaev, M.M.


    The kinetics and mechanism of radiation-stimulated process in 1 mole/1 l of potassium hydroxide have been studied. Radiation chemical yield of (G(As)(Y)) oxygenation grows directly proportionally to oxygen concentration and inversely proportionally to dose rate in proportion 1/2. Mechanism of oxidation, including two chain cycles (long chain cycle - with participation of O - ; O 2 - ; O 3 - radicals and short chain one -with participation of arsenic contenting radicals: As(IV), As(IV)O, As(IV)O 2 ) is proposed. (author)

  20. Strong Arcwise Connectedness


    Espinoza, Benjamin; Gartside, Paul; Kovan-Bakan, Merve; Mamatelashvili, Ana


    A space is `n-strong arc connected' (n-sac) if for any n points in the space there is an arc in the space visiting them in order. A space is omega-strong arc connected (omega-sac) if it is n-sac for all n. We study these properties in finite graphs, regular continua, and rational continua. There are no 4-sac graphs, but there are 3-sac graphs and graphs which are 2-sac but not 3-sac. For every n there is an n-sac regular continuum, but no regular continuum is omega-sac. There is an omega-sac ...

  1. Abortion: Strong's counterexamples fail

    DEFF Research Database (Denmark)

    Di Nucci, Ezio


    This paper shows that the counterexamples proposed by Strong in 2008 in the Journal of Medical Ethics to Marquis's argument against abortion fail. Strong's basic idea is that there are cases--for example, terminally ill patients--where killing an adult human being is prima facie seriously morally......'s scenarios have some valuable future or admitted that killing them is not seriously morally wrong. Finally, if "valuable future" is interpreted as referring to objective standards, one ends up with implausible and unpalatable moral claims....

  2. Assessing ocean alkalinity for carbon sequestration (United States)

    Renforth, Phil; Henderson, Gideon


    Over the coming century humanity may need to find reservoirs to store several trillions of tons of carbon dioxide (CO2) emitted from fossil fuel combustion, which would otherwise cause dangerous climate change if it were left in the atmosphere. Carbon storage in the ocean as bicarbonate ions (by increasing ocean alkalinity) has received very little attention. Yet recent work suggests sufficient capacity to sequester copious quantities of CO2. It may be possible to sequester hundreds of billions to trillions of tons of C without surpassing postindustrial average carbonate saturation states in the surface ocean. When globally distributed, the impact of elevated alkalinity is potentially small and may help ameliorate the effects of ocean acidification. However, the local impact around addition sites may be more acute but is specific to the mineral and technology. The alkalinity of the ocean increases naturally because of rock weathering in which >1.5 mol of carbon are removed from the atmosphere for every mole of magnesium or calcium dissolved from silicate minerals (e.g., wollastonite, olivine, and anorthite) and 0.5 mol for carbonate minerals (e.g., calcite and dolomite). These processes are responsible for naturally sequestering 0.5 billion tons of CO2 per year. Alkalinity is reduced in the ocean through carbonate mineral precipitation, which is almost exclusively formed from biological activity. Most of the previous work on the biological response to changes in carbonate chemistry have focused on acidifying conditions. More research is required to understand carbonate precipitation at elevated alkalinity to constrain the longevity of carbon storage. A range of technologies have been proposed to increase ocean alkalinity (accelerated weathering of limestone, enhanced weathering, electrochemical promoted weathering, and ocean liming), the cost of which may be comparable to alternative carbon sequestration proposals (e.g., $20-100 tCO2-1). There are still many

  3. A unified ion chromatographic system for the determination of acidity and alkalinity. (United States)

    Hu, W; Hasebe, K; Iles, A; Tanaka, K


    A unified ion chromatographic (IC) system was developed for the determination of acidity or alkalinity. Separation column used was a reversed-phase ODS packed column, which had been modified by saturating it with lithium dodecylsulfate. A slightly acidified LiCl (50 mM LiCl and 0.05 mM H2SO4) aqueous solution was used as the eluent. By conditioning the separation column in this way, both H+ and Li+ ions became bound to the stationary phase. Dodecylsulfate groups with Li+ counterions acted as cation-exchange sites for the separation of hydrogen ions (free acidity determination). The remaining dodecylsulfate groups, with H+ counterions acted as a titrant, which reacted with basic species (total alkalinity determination). The acidity or alkalinity of each sample was measured according to the change in conductance from the eluent baseline level. A positive peak was observed from those samples with a free acidity greater than their total alkalinity, due to the separation/elution of free H+ ions. A negative peak was observed from those samples with a free acidity less than their total alkalinity. This was due to an equivalent amount of eluent H+ ions being re-supplied to the stationary phase while the "solid titrant" consumed by the acid-base reaction was regenerated. The retention time for the peak corresponding to the acidity or alkalinity was governed by the retention time for H+ ions in this IC system. Samples with a free acidity greater than 2.25 microM (tested by determination of H+ ions in pure water in equilibrium with atmospheric CO2) could be analyzed by this method. A very similar detection level was obtained for alkalinity (tested by analyzing standard aqueous NaHCO3 solutions). Aqueous solutions of some strong-acid/strong-base inorganic salts were found to be slightly alkaline. This was measured as a percentage, relative to an NaHCO3 solution at the same concentration. Solutions of NaClO4, Na2SO4, NaI, NaNO3, and NaCl, gave comparative alkalinity values of 8

  4. Catalytic oxidation of soot over alkaline niobates

    International Nuclear Information System (INIS)

    Pecchi, G.; Cabrera, B.; Buljan, A.; Delgado, E.J.; Gordon, A.L.; Jimenez, R.


    Highlights: ► No previous reported studies about alkaline niobates as catalysts for soot oxidation. ► NaNbO 3 and KNbO 3 perovskite-type oxides show lower activation energy than other lanthanoid perovskite-type oxides. ► The alkaline niobate does not show deactivation by metal loss. - Abstract: The lack of studies in the current literature about the assessment of alkaline niobates as catalysts for soot oxidation has motivated this research. In this study, the synthesis, characterization and assessment of alkaline metal niobates as catalysts for soot combustion are reported. The solids MNbO 3 (M = Li, Na, K, Rb) are synthesized by a citrate method, calcined at 450 °C, 550 °C, 650 °C, 750 °C, and characterized by AAS, N 2 adsorption, XRD, O 2 -TPD, FTIR and SEM. All the alkaline niobates show catalytic activity for soot combustion, and the activity depends basically on the nature of the alkaline metal and the calcination temperature. The highest catalytic activity, expressed as the temperature at which combustion of carbon black occurs at the maximum rate, is shown by KNbO 3 calcined at 650 °C. At this calcination temperature, the catalytic activity follows an order dependent on the atomic number, namely: KNbO 3 > NaNbO 3 > LiNbO 3 . The RbNbO 3 solid do not follow this trend presumably due to the perovskite structure was not reached. The highest catalytic activity shown by of KNbO 3 , despite the lower apparent activation energy of NaNbO 3 , stress the importance of the metal nature and suggests the hypothesis that K + ions are the active sites for soot combustion. It must be pointed out that alkaline niobate subjected to consecutive soot combustion cycles does not show deactivation by metal loss, due to the stabilization of the alkaline metal inside the perovskite structure.

  5. Separation of pig bone alkaline phosphatase activities. (United States)

    Leunis, J C; Vancraeynest, T; Brauman, J


    A simple method for the separation of alkaline phosphatase and pyrophosphatase activities of pig bone ribs is described. Using anionic exchange chromatography (DEAE-cellulose) and affinity chromatography on Concanavalin A sepharose (Con A) eluted by a step pH gradient and Na4P2O7, several activities were obtained. A pyrophosphatase containing very little alkaline phosphatase activity was isolated from Con A sepharose by elution with pyrophosphatase. Our data are consistent, with the hypothesis that cortical alcaline phosphatase and pyrophosphatase activities are not due to a single enzyme protein. The method was used on whole bone, on bone marrow and on cortical bone.

  6. Alkaline earth filled nickel skutterudite antimonide thermoelectrics (United States)

    Singh, David Joseph


    A thermoelectric material including a body centered cubic filled skutterudite having the formula A.sub.xFe.sub.yNi.sub.zSb.sub.12, where A is an alkaline earth element, x is no more than approximately 1.0, and the sum of y and z is approximately equal to 4.0. The alkaline earth element includes guest atoms selected from the group consisting of Be, Mb, Ca, Sr, Ba, Ra and combinations thereof. The filled skutterudite is shown to have properties suitable for a wide variety of thermoelectric applications.

  7. Alkaline ionic liquids applied in supported ionic liquid catalyst for selective hydrogenation of citral to citronellal (United States)

    Salminen, Eero; Virtanen, Pasi; Mikkola, Jyri-Pekka


    The challenge in preparation of ionic liquids containing a strong alkaline anion is to identify a suitable cation which can tolerate the harsh conditions induced by the anion. In this study, a commercial quaternary ammonium compound (quat) benzalkonium [ADBA] (alkyldimethylbenzylammonium) was used as a cation in the synthesis of different alkaline ionic liquids. In fact, the precursor, benzalkonium chloride, is a mixture of alkyldimethylbenzylammonium chlorides of various alkyl chain lengths and is commonly used in the formulation of various antiseptic products. The prepared ionic liquids were utilized as Supported Ionic Liquid Catalysts (SILCAs). Typically, a SILCA contains metal nanoparticles, enzymes, or metal complexes in an ionic liquid layer which is immobilized on a solid carrier material such as an active carbon cloth (ACC). The catalysts were applied in the selective hydrogenation of citral to citronellal which is an important perfumery chemical. Interestingly, 70% molar yield toward citronellal was achieved over a catalyst containing the alkaline ionic liquid benzalkonium methoxide. PMID:24790972

  8. Alkaline ionic liquids applied in supported ionic liquid catalyst for selective hydrogenation of citral to citronellal

    Directory of Open Access Journals (Sweden)

    Eero eSalminen


    Full Text Available The challenge in preparation of ionic liquids containing a strong alkaline anion is to identify a suitable cation which can tolerate the harsh conditions induced by the anion. In this study, a commercial quaternary ammonium compound (quat benzalkonium [ADBA] (alkyldimethylbenzylammonium was used as a cation in the synthesis of different alkaline ionic liquids. In fact, the precursor, benzalkonium chloride, is a mixture of alkyldimethylbenzylammonium chlorides of various alkyl chain lengths and is commonly used in the formulation of various antiseptic products. The prepared ionic liquids were utilized as Supported Ionic Liquid Catalysts (SILCAs. Typically, a SILCA contains metal nanoparticles, enzymes or metal complexes in an ionic liquid layer which is immobilized on a solid carrier material such as an active carbon cloth (ACC. The catalysts were applied in the selective hydrogenation of citral to citronellal which is an important perfumery chemical. Interestingly, 70 % molar yield towards citronellal was achieved over a catalyst containing the alkaline ionic liquid benzalkonium methoxide.

  9. Eichrom's ABEC trademark resins: Alkaline radioactive waste treatment, radiopharmaceutical, and potential hydrometallurgical applications

    International Nuclear Information System (INIS)

    Bond, A.H.; Gula, M.J.; Chang, F.; Rogers, R.D.


    Eichrom's ABEC trademark resins selectivity extract certain anions from high ionic strength acidic, neutral, or strongly alkaline media, and solute stripping can be accomplished by eluting with water. ABEC resins are stable to pH extreme and radiolysis and operate in high ionic strength and/or alkaline solutions where anion-exchange is often ineffective. Potential applications of the ABEC materials include heavy metal and ReO 4 - separations in hydrometallurgy and purification of perrhenate iodide, and iodate in radiopharmaceutical production. Separation of 99m TcO 4 - from its 99 MoO 4 2- parent and stripping with water or physiological saline solution have been demonstrated for radiopharmaceutical applications. Removal of 99 TcO 4 - and 129 I - from alkaline tank wastes has also been successfully demonstrated. The authors will discuss the scale-up studies, process-scale testing, and market development of this new extraction material

  10. A strong comeback

    International Nuclear Information System (INIS)

    Marier, D.


    This article presents the results of a financial rankings survey which show a strong economic activity in the independent energy industry. The topics of the article include advisor turnover, overseas banks, and the increase in public offerings. The article identifies the top project finance investors for new projects and restructurings and rankings for lenders

  11. Enhanced visible light generation in an active microcavity via third-harmonic conversion beyond the non-depletion approximation (United States)

    Yu, Rong; Ding, Chunling; Wang, Jiangpeng; Zhang, Duo


    We explore the possibility of using an active doubly resonant microtoroid resonator to produce high-efficiency third-harmonic generation (THG) by exploiting optical third-order nonlinearity. In a microresonator, the active fundamental mode is coherently driven with a continuous-wave input laser at the telecommunication wavelength (1550 nm), and then, the visible THG signal (517 nm) is monitored via an individual bus waveguide. We thoroughly compare our results with those obtained from the conventional passive (i.e., loss) microtoroid resonator by a systematic analysis and detailed numerical simulations based on the Heisenberg-Langevin equations of motion. It is shown that the achievable THG spectrum features an ultralow critical input power. The THG power transmission can be significantly enhanced by about three orders of magnitude at a low input power of 0.1 μ W as compared with the obtained results in the passive microtoroid resonator THG system. Moreover, the THG efficiency can reach up to 100% with optical critical input power as low as a few microwatts. In turn, the analytical expressions of the critical intracavity intensity of the light in the microcavity, the critical input pump power, and the maximum THG efficiency are obtained. The enhanced THG power transmission and high conversion efficiency are attributed to a gain-induced loss compensation in the microtoroid resonator, reducing the effective loss felt by the resonator photons. With state-of-the art technologies in the field of solid-state resonators, including but not limited to microtoroids, the proposed THG scheme is experimentally realizable.

  12. Determination of Acidity and Alkalinity of Food Materials


    三浦,芳助; 福永,祐子; 瀧川,裕里子; 津田,真美; 渡辺,陽子; 瀨山,一正


    The acidity and alkalinity of food materials in various menus was determined to clarify the influence of food on physiological functions. Menus mainly containing alkaline food materials (alkaline menu) and acid ones (acid menu) were compared. Determination of acidity and alkalinity was performed for each food material in the alkaline menu and acid menu, and acidity and alkalinity of one meal and a day's one were estimated. 1. Most of food materials in acid menu were assessed to be...

  13. Production optimization of a heat-tolerant alkaline pectinase from Bacillus subtilis ZGL14 and its purification and characterization. (United States)

    Yu, Ping; Zhang, Yishu; Gu, Donglu


    Alkaline pectinase has important applications in the pretreatment of waste water from food processing and in both the fabric and paper industries. In this study, a 2-level factorial design was used to screen significant factors that affect the activity of alkaline pectinase, and the response surface methodology (RSM) with a Box-Behnken design (BBD) was used to optimize their concentrations. Starch, peptone, KH 2 PO 4 and K 2 HPO 4 ·3H 2 O were found to significantly affect the activity of alkaline pectinase. Their optimal concentrations were as follows: 4.68% starch, 1.6% peptone, 0.26% KH 2 PO 4 and 0.68% K 2 HPO 4 ·3H 2 O. Under the above conditions, the activity of alkaline pectinase was significantly improved to 734.11 U/mL. Alkaline pectinase was purified to homogeneity with a recovery rate of 9.6% and a specific activity of 52372.52 U/mg. Its optimal temperature and pH were 50°C and 8.6, respectively. The purified enzyme showed strong thermo-stability and good alkali resistance. In addition, the activity of alkaline pectinase was improved in the presence of Mg 2+ . Cu 2+ , Mn 2+ , and Co 2+ significantly inhibited its activity. This study provides an important basis for the future development and use of a heat-tolerant alkaline pectinase from B. subtilis ZGL14.

  14. The Alkaline Diet: Is There Evidence That an Alkaline pH Diet Benefits Health?

    Directory of Open Access Journals (Sweden)

    Gerry K. Schwalfenberg


    Full Text Available This review looks at the role of an alkaline diet in health. Pubmed was searched looking for articles on pH, potential renal acid loads, bone health, muscle, growth hormone, back pain, vitamin D and chemotherapy. Many books written in the lay literature on the alkaline diet were also reviewed and evaluated in light of the published medical literature. There may be some value in considering an alkaline diet in reducing morbidity and mortality from chronic diseases and further studies are warranted in this area of medicine.

  15. Spectrally tunable mollow triplet emission from a coherently excited quantum dot in a microcavity

    DEFF Research Database (Denmark)

    Ulrich, Sven M.; Ates, Serkan; Reitzenstein, Stephan


    Resonance fluorescence of excitonic s-shell emission from a coherently pumped single InGaAs/GaAs quantum dot inside a micropillar cavity has been investigated in dependence on optical pump power and laser detuning, respectively. For strong purely resonant excitation, Mollow triplet spectra with l...... with large Rabi splittings of j~­j » 60¹eV have been observed. Laser detuning-dependent series revealed the pronounced asymmetry of the emission triplet as predicted by theory. From our data, an electrical dipole moment of ¹ » 17:8§0:5 Debye could be derived for the excitonic state....

  16. Intestinal alkaline phosphatase: novel functions and protective effects. (United States)

    Lallès, Jean-Paul


    Important protective roles of intestinal alkaline phosphatase (IAP)--including regulation of intestinal surface pH, absorption of lipids, detoxification of free nucleotides and bacterial lipopolysaccharide, attenuation of intestinal inflammation, and possible modulation of the gut microbiota--have been reviewed recently. IAP is modulated by numerous nutritional factors. The present review highlights new findings on the properties of IAP and extends the list of its protective functions. Critical assessment of data suggests that some IAP properties are a direct result of dephosphorylation of proinflammatory moieties, while others (e.g., gut barrier protection and microbiota shaping) may be secondary to IAP-mediated downregulation of inflammation. IAP and tissue-nonspecific alkaline phosphatase isoforms characterize the small intestine and the colon, respectively. Gastrointestinal administration of exogenous IAP ameliorates gut inflammation and favors gut tissue regeneration, whereas enteral and systemic IAP administration attenuates systemic inflammation only. Finally, the IAP gene family has a strong evolutionary link to food-driven changes in gastrointestinal tract anatomy and microbiota composition. Therefore, stimulation of IAP activity by dietary intervention is a goal for preserving gut homeostasis and health by minimizing low-grade inflammation. © 2013 International Life Sciences Institute.

  17. Effect of alkaline pretreatment on delignification of wheat straw. (United States)

    Asghar, Umar; Irfan, Muhammad; Iram, Mehvish; Huma, Zile; Nelofer, Rubina; Nadeem, Muhammad; Syed, Quratulain


    This study was conducted to analyse structural changes through scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) after alkaline pretreatment of wheat straw for optimum steaming period. During the study, 2 mm size of substrate was soaked in 2.5% NaOH for 1 h at room temperature and then autoclaved at 121°C for various steaming time (30, 60, 90 and 120 min). Results revealed that residence time of 90 min at 121°C has strong effect on substrate, achieving a maximum cellulose content of 83%, delignification of 81% and hemicellulose content of 10.5%. Further SEM and FTIR spectroscopy confirmed structural modification caused by alkaline pretreatment in substrate. Maximum saccharification yield of 52.93% was achieved with 0.5% enzyme concentration using 2.5% substrate concentration for 8 h of incubation at 50°C. This result indicates that the above-mentioned pretreatment conditions create accessible areas for enzymatic hydrolysis.

  18. Strong Electroweak Symmetry Breaking

    CERN Document Server

    Grinstein, Benjamin


    Models of spontaneous breaking of electroweak symmetry by a strong interaction do not have fine tuning/hierarchy problem. They are conceptually elegant and use the only mechanism of spontaneous breaking of a gauge symmetry that is known to occur in nature. The simplest model, minimal technicolor with extended technicolor interactions, is appealing because one can calculate by scaling up from QCD. But it is ruled out on many counts: inappropriately low quark and lepton masses (or excessive FCNC), bad electroweak data fits, light scalar and vector states, etc. However, nature may not choose the minimal model and then we are stuck: except possibly through lattice simulations, we are unable to compute and test the models. In the LHC era it therefore makes sense to abandon specific models (of strong EW breaking) and concentrate on generic features that may indicate discovery. The Technicolor Straw Man is not a model but a parametrized search strategy inspired by a remarkable generic feature of walking technicolor,...

  19. Potentiometric assay for acid and alkaline phosphatase

    International Nuclear Information System (INIS)

    Koncki, Robert; Ogonczyk, Dominika; Glab, Stanislaw


    Simple potentiometric kinetic assay for evaluation of acid and alkaline phosphatase activity has been developed. Enzymatically catalyzed hydrolysis of monofluorophosphate, the simplest inorganic compound containing P-F bond, has been investigated as the basis of the assays. Fluoride ions formed in the course of the hydrolysis of this specific substrate have been detected using conventional fluoride ion-selective electrode based on membrane made of lanthanum fluoride. The key analytical parameters necessary for sensitive and selective detection of both enzymes have been assessed. Maximal sensitivity of the assays was observed at monofluorophosphate concentration near 10 -3 M. Maximal sensitivity of acid phosphatase assay was found at pH 6.0, but pH of 4.8 is recommended to eliminate effects from alkaline phosphatase. Optimal pH for alkaline phosphatase assay is 9.0. The utility of the developed substrate-sensor system for determination of acid and alkaline phosphatase activity in human serum has been demonstrated

  20. Optical properties of alkaline earth borate glasses

    African Journals Online (AJOL)


    applications in the field of optical fibers, optoelectronic devices; radiation shields, surgical lasers and their glass ceramic counter parts have wide range of applications (Rajasree et al., 2011; Sharma et al., 2007, Limkitjaroenporn et al., 2010). Boric acid. (H3BO3) form stable glasses with alkaline earth oxides (R= MgO, CaO, ...

  1. Qualitative Carbohydrate Analysis using Alkaline Potassium ...

    Indian Academy of Sciences (India)

    IAS Admin

    and yellow colour appears. Initial colour remains but fades. Orange colour appears. Yellow colour appears. Carbohydrates. Monosaccharide. Disaccharide. + Alkaline ferricyanide (shake for 5 minutes). Colour disappears. Colour does not disappear. Put the test tube in boiling water for 10 seconds. Put the test tube in boiling.

  2. Optimization of alkaline protease production from Pseudomonas ...

    African Journals Online (AJOL)



    Dec 15, 2009 ... the metal ions tested. Key words: Alkaline protease, casein agar, meat waste contaminated soil, Pseudomonas fluorescens. INTRODUCTION. Proteases are the most important industrial enzymes that execute a wide variety of functions and have various important biotechnological applications (Mohen et al.,.

  3. Plasmons in strong superconductors

    International Nuclear Information System (INIS)

    Baldo, M.; Ducoin, C.


    We present a study of the possible plasmon excitations that can occur in systems where strong superconductivity is present. In these systems the plasmon energy is comparable to or smaller than the pairing gap. As a prototype of these systems we consider the proton component of Neutron Star matter just below the crust when electron screening is not taken into account. For the realistic case we consider in detail the different aspects of the elementary excitations when the proton, electron components are considered within the Random-Phase Approximation generalized to the superfluid case, while the influence of the neutron component is considered only at qualitative level. Electron screening plays a major role in modifying the proton spectrum and spectral function. At the same time the electron plasmon is strongly modified and damped by the indirect coupling with the superfluid proton component, even at moderately low values of the gap. The excitation spectrum shows the interplay of the different components and their relevance for each excitation modes. The results are relevant for neutrino physics and thermodynamical processes in neutron stars. If electron screening is neglected, the spectral properties of the proton component show some resemblance with the physical situation in high-T c superconductors, and we briefly discuss similarities and differences in this connection. In a general prospect, the results of the study emphasize the role of Coulomb interaction in strong superconductors.

  4. Alkaline earth metal catalysts for asymmetric reactions. (United States)

    Kobayashi, Shū; Yamashita, Yasuhiro


    The group 2 alkaline earth metals calcium (Ca), strontium (Sr), and barium (Ba) are among the most common elements on Earth, abundant in both the sea and the Earth's crust. Although they are familiar in our daily lives, their application to organic synthesis has, so far, been limited. Some particularly useful properties of these elements include (i) low electronegativity, (ii) a stable oxidation state of +2, meaning that they can potentially form two covalent bonds with anions, and (iii) the ability to occupy a variety of coordination sites due to their large ionic radius. Furthermore, the alkaline earth metals, found between the group 1 and group 3 elements, show mild but significant Lewis acidity, which can be harnessed to control coordinative molecules via a Lewis acid-base interaction. Taken together, these characteristics make the metals Ca, Sr, and Ba very promising components of highly functionalized acid-base catalysts. In this Account, we describe the development of chiral alkaline earth metal catalysts for asymmetric carbon-carbon bond-forming reactions. Recently prepared chiral alkaline earth metal complexes have shown high diastereo- and enantioselectivities in fundamental and important chemical transformations. We chose chiral bisoxazoline (Box) derivatives bearing a methylene tether as a ligand for chiral modification. These molecules are very useful because they can covalently coordinate to alkaline earth metals in a bidentate fashion through deprotonation of the tether portion. It was found that chiral calcium-Box complexes could successfully promote catalytic asymmetric 1,4-addition and [3 + 2] cycloaddition reactions with high diastereo- and enantioselectivities. Both the calcium-Box complexes and chiral strontium-bis-sulfonamide and chiral barium-BINOLate complexes could catalyze asymmetric 1,4-addition reactions with high enantioselectivities. Furthermore, we designed a calcium-neutral coordinative ligand complex as a new type of chiral alkaline

  5. Osteocalcin and bone-specific alkaline phosphatase in Sickle cell ...

    African Journals Online (AJOL)

    specific alkaline phosphatase (b-AP) total protein levels were evaluated as indicators of bone turnover in twenty patients with sickle cell haemoglobinopathies and in twenty normal healthy individuals. The serum bonespecific alkaline phosphatase ...

  6. Electrically tunable strong light-matter coupling in a transition metal dichalcogenide monolayer embedded in a plasmonic crystal cavity (United States)

    Scuri, Giovanni; Zhou, You; High, Alexander; Dibos, Alan; de Greve, Kristiaan; Polking, Mark; Juaregui, Luis; Wild, Dominik; Joe, Andrew; Pistunova, Kateryna; Lukin, Mikhail; Kim, Philip; Park, Hongkun

    Two-dimensional transition-metal dichalcogenide (TMDC) monolayers exhibit direct bandgap excitons with large binding energy. The optical response of TMDCs is electrically tunable over a broad wavelength range, making these 2D materials promising candidates for optoelectronic devices. In this work, we enhance exciton-plasmon coupling by embedding a single layer of tungsten diselenide (WSe2) into a plasmonic crystal cavity, which confines surface plasmon polaritons in an analogous manner to photonic crystal cavities. We observe strong light-matter interactions and the formation of microcavity polaritons when the cavity mode is on resonance with the exciton absorption in WSe2. Using the electrostatically controllable response of such excitons, we also demonstrate tunable vacuum Rabi splitting in such a system.

  7. Strong-coupling approximations

    International Nuclear Information System (INIS)

    Abbott, R.B.


    Standard path-integral techniques such as instanton calculations give good answers for weak-coupling problems, but become unreliable for strong-coupling. Here we consider a method of replacing the original potential by a suitably chosen harmonic oscillator potential. Physically this is motivated by the fact that potential barriers below the level of the ground-state energy of a quantum-mechanical system have little effect. Numerically, results are good, both for quantum-mechanical problems and for massive phi 4 field theory in 1 + 1 dimensions. 9 references, 6 figures

  8. Strong interaction and QFD

    International Nuclear Information System (INIS)

    Ebata, T.


    With an assumed weak multiplet structure for bosonic hadrons, which is consistent with the ΔI = 1/2 rule, it is shown that the strong interaction effective hamiltonian is compatible with the weak SU(2) x U(1) gauge transformation. Especially the rho-meson transforms as a triplet under SU(2)sub(w), and this is the origin of the rho-photon analogy. It is also shown that the existence of the non-vanishing Cabibbo angle is a necessary condition for the absence of the exotic hadrons. (orig.)

  9. Strong Coupling Holography

    CERN Document Server

    Dvali, Gia


    We show that whenever a 4-dimensional theory with N particle species emerges as a consistent low energy description of a 3-brane embedded in an asymptotically-flat (4+d)-dimensional space, the holographic scale of high-dimensional gravity sets the strong coupling scale of the 4D theory. This connection persists in the limit in which gravity can be consistently decoupled. We demonstrate this effect for orbifold planes, as well as for the solitonic branes and string theoretic D-branes. In all cases the emergence of a 4D strong coupling scale from bulk holography is a persistent phenomenon. The effect turns out to be insensitive even to such extreme deformations of the brane action that seemingly shield 4D theory from the bulk gravity effects. A well understood example of such deformation is given by large 4D Einstein term in the 3-brane action, which is known to suppress the strength of 5D gravity at short distances and change the 5D Newton's law into the four-dimensional one. Nevertheless, we observe that the ...

  10. On performance capabilities of alkaline anolyte in wastewater management

    International Nuclear Information System (INIS)

    Shimkevich, Alexander


    A concept for electric converting a saline wastewater into basic solution (pH > 7) with a positive RedOx potential (alkaline anolyte) is considered. Such the medium can be obtained in situ at flowing wastewater via a special electrochemical cell with strongly polarized cathode (generating hydroxide anions) and quasi-equilibrium anode which intensively discharges hydroxide ions to hydroxyl radicals into the wastewater. The radicals will oxidize anions of strong acid and convert them into weak-acid micro precipitates in the flowing basic solution. These renewable nano-sorbents will uninterruptedly co-precipitate radioactive contamination from wastewater and be agglomerated as corrosion by-products in the felt-like anode. The consideration of liquid water as a chemical compound with a wide band gap shows that the anolyte (as a hyper-stoichiometric water, H 2 O 1+|x| ) is a simple and effective tool for varying physical and chemical properties of the aqueous solution due to forced changing its RedOx potential as one needs. This potential as Fermi level in the band gap of liquid water is the most convenient parameter for monitoring and managing the electrochemical potential of the aqueous medium. Its hyper-stoichiometric state is realized when Fermi level is shifted to the top of a valence band. This electro-oxidized state as the alkaline anolyte is characterized by an acceptor level, OH/OH - , partially occupied by electrons. Then, the hydroxyl radical (OH • ) as the strongest oxidizer will oxidize intensively the metal anode and renew its surface for great removal of radio-nuclides from the wastewater due to their large specific area of renewable surface of hydroxide absorber on the felt-like anode. (author)

  11. LIGO: The strong belief

    CERN Multimedia

    Antonella Del Rosso


    Twenty years of designing, building and testing a number of innovative technologies, with the strong belief that the endeavour would lead to a historic breakthrough. The Bulletin publishes an abstract of the Courier’s interview with Barry Barish, one of the founding fathers of LIGO.   The plots show the signals of gravitational waves detected by the twin LIGO observatories at Livingston, Louisiana, and Hanford, Washington. (Image: Caltech/MIT/LIGO Lab) On 11 February, the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo collaborations published a historic paper in which they showed a gravitational signal emitted by the merger of two black holes. These results come after 20 years of hard work by a large collaboration of scientists operating the two LIGO observatories in the US. Barry Barish, Linde Professor of Physics, Emeritus at the California Institute of Technology and former Director of the Global Design Effort for the Internat...

  12. Novel hybrid laser modes in composite VCSEL-DFB microcavities (Conference Presentation) (United States)

    Mischok, Andreas; Wagner, Tim; Sudzius, Markas; Brückner, Robert; Fröb, Hartmut; Lyssenko, Vadim G.; Leo, Karl


    Two of the most successful microcresonator concepts are the vertical cavity surface emitting laser (VCSEL), where light is confined between distributed Bragg reflectors (DBRs), and the distributed feedback (DFB) laser, where a periodic grating provides positive optical feedback to selected modes in an active waveguide (WG) layer. Our work concerns the combination of both into a composite device, facilitating coherent interaction between both regimes and giving rise to novel laser modes in the system. In a first realization, a full VCSEL stack with an organic active layer is evaporated on top of a diffraction grating with a large period (approximately 1 micron), leading to diffraction of waveguided modes into the surface emission of the device. Here, the coherent interaction between VCSEL and WG modes, as observed in an anticrossing of the dispersion lines, facilitates novel hybrid lasing modes with macroscopic in-plane coherence [1]. In further studies, we decrease the grating period of such devices to realise DFB conditions in a second-order Bragg grating which strongly couples photons via first-order light diffraction to the VCSEL. This efficient coupling can be compared to more classical cascade-coupled cavities and is successfully described by a coupled oscillator model [2]. When both resonators are non-degenerate, they are able to function as independent structures without substantial diffraction losses. The realization of such novel devices provides a promising platform for photonic circuits based on organic microlasers. [1] A. Mischok et al., Adv. Opt. Mater., early online, DOI: 10.1002/adom.201600282, (2016) [2] T. Wagner et al., Appl. Phys. Lett., accepted, in production, (2016)

  13. Genesis of post-collisional calc-alkaline and alkaline granitoids in Qiman Tagh, East Kunlun, China (United States)

    Yu, Miao; Feng, Chengyou; Zhao, Yiming; Li, Daxin


    The post-collisional magmatism of Qiman Tagh is characterized by the intrusion of voluminous intermediate to felsic granitoids, including syenogranite, monzogranite, granodiorite, tonalite and diorite. The granitoids can be divided into two magmatic suites: Calc-alkaline (CA) and alkaline (Alk), which were emplaced from ~ 236 Ma to ~ 204 Ma. The CA suite contains metaluminous granodiorites and monzogranites. Typical Qiman Tagh CA granodiorites show moderately fractionated REE patterns ((La/Yb)N = 4.35-25.11) with significant negative Eu anomalies (Eu/Eu* = 0.54-1.34), and the primitive mantle-normalized spidergrams show strong depletion of Nb and Sr. The Qiman Tagh CA monzogranites show similar fractionated REE patterns ((La/Yb)N = 2.70-13.5) with less prominent negative Eu anomalies, and the chondrite-normalized spidergrams show strongly depleted Ba, Nb and Sr. The Alk suite, including syenogranite, is highly potassic (K2O/Na2O = 1.09-3.56) and peraluminous (A/CNK = 0.91-1.06). Compared to typical Qiman Tagh CA granodiorites, the Qiman Tagh Alk granitoids can be distinguished by their higher Rb, Nb, Ga/Al, FeO*/MgO, Y/Sr and Rb/Sr, as well as their lower Mg#, MgO, CaO, Al2O3, Sr, Co, V, Eu/Eu*, Ba/Nb, La/Nb, Ba/La and Ce/Nb. The Qiman Tagh CA rocks were most likely to be derived from the partial melting of garnet-amphibolite-facies rocks in the lower crust, leaving behind anhydrous granulite-facies rocks with plagioclase and garnet in the residue. The Alk rocks may have formed by the continued partial melting of granulite-facies rocks at elevated temperatures (> 830 °C).

  14. Study of niobium corrosion in alkaline medium

    International Nuclear Information System (INIS)

    Almeida, S.H. de.


    A comparative study of niobium electrochemical behaviour in NaOH and KOH solution, with concentrations between 0,5 and 6,1M is presented. The studies were done through electrochemicals assays, consisting in the corrosion potential and anodic and cathodic polarization curves, complemented by loss of mass experiments. The niobium anodic behaviour in alkaline medium is characterized by passivation occurrence, with a stable film formation. The Na oH solution in alkaline medium are more corrosible to niobium than the KOH solution. The loss of mass assays showed that the corrosion velocit is more dependente of hydroxide concentration in KOH medium than the NaOH medium. (C.G.C.) [pt

  15. Photolysis of alkaline-earth nitrates (United States)

    Kriger, L. D.; Miklin, M. B.; Dyagileva, E. P.; Anan'ev, V. A.


    Peroxynitrite and nitrite ions are the diamagnetic products of photolysis (with light at a wavelength of 253.7 nm) of alkaline-earth nitrates; the paramagnetic products and hydrogen peroxide were not found. The structural water in alkaline-earth nitrate crystals did not affect the qualitative composition of the photodecomposition products. The quantum yield of nitrite ions was 0.0012, 0.0038, 0.0078, and 0.0091 quanta-1 and that of peroxynitrite ions was 0.0070, 0.0107, 0.0286, and 0.0407 quanta-1 for Sr(NO3)2, Ba(NO3)2, Ca(NO3)2 · 4H2O, and Mg(NO3)2 · 6H2O, respectively.

  16. Hydrolysis of alkaline pretreated banana peel (United States)

    Fatmawati, A.; Gunawan, K. Y.; Hadiwijaya, F. A.


    Banana peel is one of food wastes that are rich in carbohydrate. This shows its potential as fermentation substrate including bio-ethanol. This paper presented banana peel alkaline pretreatment and enzymatic hydrolysis. The pretreatment was intended to prepare banana peel in order to increase hydrolysis performance. The alkaline pretreatment used 10, 20, and 30% w/v NaOH solution and was done at 60, 70 and 80°C for 1 hour. The hydrolysis reaction was conducted using two commercial cellulose enzymes. The reaction time was varied for 3, 5, and 7 days. The best condition for pretreatment process was one conducted using 30% NaOH solution and at 80°C. This condition resulted in cellulose content of 90.27% and acid insoluble lignin content of 2.88%. Seven-day hydrolysis time had exhibited the highest reducing sugar concentration, which was7.2869 g/L.

  17. Oxidation catalysts on alkaline earth supports (United States)

    Mohajeri, Nahid


    An oxidation catalyst includes a support including particles of an alkaline earth salt, and first particles including a palladium compound on the support. The oxidation catalyst can also include precious metal group (PMG) metal particles in addition to the first particles intermixed together on the support. A gas permeable polymer that provides a continuous phase can completely encapsulate the particles and the support. The oxidation catalyst may be used as a gas sensor, where the first particles are chemochromic particles.

  18. Purification and characterisation of alkaline phosphotase enzyme ...

    African Journals Online (AJOL)

    L'enzyme phosphatase alkaline était purifié de la bactérie Escherichia coli C90 cultivé dans un médium pauvre en phosphate comme phase stationnaire utilisant une colonne d'échange d'ion enveloppée avec une cellulose DEAE comme matrice et exclusion de taille chromographique utilisant le Sepharcryl S-300HR ...

  19. Degradation of polymers in an alkaline environment

    Energy Technology Data Exchange (ETDEWEB)

    Borges, P. G.; Thorpe, S. J.; Venter, R. D. [Toronto Univ., Toronto, ON (Canada)


    To introduce widespread use of hydrogen as a source of fuel, it is essential to significantly reduce the cost of electrolysers and fuel cells, preferably by substituting degradation-resistant low cost alternatives for traditional materials. An experimental apparatus for evaluating short-term degradation characteristics of polymers in 25 per cent potassium hydroxide aqueous solution at 70 and at 85 degrees C was constructed to determine changes in physical appearance, weight, volume and dimensions as a function of immersion time from 0 to 670 hours. Polymers that were part of this test included chlorinated polyvinyl chloride (CPVC), polypropylene (PP),and a polyurethane/polyester blend. Polypropylene demonstrated the greatest degradation resistance to the alkaline environment at both temperatures. CPVC discolored and the polyurethane/polyester blend deteriorated into smaller pieces when subjected to identical conditions. Resistance to degradation in an alkaline environment is a primary requirement for the selection of polymers for use as structural materials in alkaline water analyzers, which in turn is fundamental to the widespread adoption of a hydrogen economy. 6 refs., 13 figs.

  20. John Strong (1941 - 2006)

    CERN Multimedia

    Wickens, F

    Our friend and colleague John Strong was cruelly taken from us by a brain tumour on Monday 31st July, a few days before his 65th birthday John started his career working with a group from Westfield College, under the leadership of Ted Bellamy. He obtained his PhD and spent the early part of his career on experiments at Rutherford Appleton Laboratory (RAL), but after the early 1970s his research was focussed on experiments in CERN. Over the years he made a number of notable contributions to experiments in CERN: The Omega spectrometer adopted a system John had originally developed for experiments at RAL using vidicon cameras to record the sparks in the spark chambers; He contributed to the success of NA1 and NA7, where he became heavily involved in the electronic trigger systems; He was responsible for the second level trigger system for the ALEPH detector and spent five years leading a team that designed and built the system, which ran for twelve years with only minor interventions. Following ALEPH he tur...

  1. Stirring Strongly Coupled Plasma

    CERN Document Server

    Fadafan, Kazem Bitaghsir; Rajagopal, Krishna; Wiedemann, Urs Achim


    We determine the energy it takes to move a test quark along a circle of radius L with angular frequency w through the strongly coupled plasma of N=4 supersymmetric Yang-Mills (SYM) theory. We find that for most values of L and w the energy deposited by stirring the plasma in this way is governed either by the drag force acting on a test quark moving through the plasma in a straight line with speed v=Lw or by the energy radiated by a quark in circular motion in the absence of any plasma, whichever is larger. There is a continuous crossover from the drag-dominated regime to the radiation-dominated regime. In the crossover regime we find evidence for significant destructive interference between energy loss due to drag and that due to radiation as if in vacuum. The rotating quark thus serves as a model system in which the relative strength of, and interplay between, two different mechanisms of parton energy loss is accessible via a controlled classical gravity calculation. We close by speculating on the implicati...

  2. Strong-interaction nonuniversality

    International Nuclear Information System (INIS)

    Volkas, R.R.; Foot, R.; He, X.; Joshi, G.C.


    The universal QCD color theory is extended to an SU(3) 1 direct product SU(3) 2 direct product SU(3) 3 gauge theory, where quarks of the ith generation transform as triplets under SU(3)/sub i/ and singlets under the other two factors. The usual color group is then identified with the diagonal subgroup, which remains exact after symmetry breaking. The gauge bosons associated with the 16 broken generators then form two massive octets under ordinary color. The interactions between quarks and these heavy gluonlike particles are explicitly nonuniversal and thus an exploration of their physical implications allows us to shed light on the fundamental issue of strong-interaction universality. Nonuniversality and weak flavor mixing are shown to generate heavy-gluon-induced flavor-changing neutral currents. The phenomenology of these processes is studied, as they provide the major experimental constraint on the extended theory. Three symmetry-breaking scenarios are presented. The first has color breaking occurring at the weak scale, while the second and third divorce the two scales. The third model has the interesting feature of radiatively induced off-diagonal Kobayashi-Maskawa matrix elements

  3. Processing Methods of Alkaline Hydrolysate from Rice Husk

    Directory of Open Access Journals (Sweden)

    Olga D. Arefieva


    Full Text Available This paper devoted to finding processing methods of alkaline hydrolysate produced from rice husk pre-extraction, and discusses alkaline hydrolysate processing schemed and disengagement of some products: amorphous silica of various quality, alkaline lignin, and water and alkaline extraction polysaccharides. Silica samples were characterized: crude (air-dried, burnt (no preliminary water treatment, washed in distilled water, and washed in distilled water and burnt. Waste water parameters upon the extraction of solids from alkaline hydrolysate dropped a few dozens or thousand times depending on the applied processing method. Color decreased a few thousand times, turbidity was virtually eliminated, chemical oxygen demanded about 20–136 times; polyphenols content might decrease 50% or be virtually eliminated. The most prospective scheme obtained the two following solid products from rice husk alkaline hydrolysate: amorphous silica and alkaline extraction polysaccharide. Chemical oxygen demand of the remaining waste water decreased about 140 times compared to the silica-free solution.

  4. Alkaline and ultrasound assisted alkaline pretreatment for intensification of delignification process from sustainable raw-material. (United States)

    Subhedar, Preeti B; Gogate, Parag R


    Alkaline and ultrasound-assisted alkaline pretreatment under mild operating conditions have been investigated for intensification of delignification. The effect of NaOH concentration, biomass loading, temperature, ultrasonic power and duty cycle on the delignification has been studied. Most favorable conditions for only alkaline pretreatment were alkali concentration of 1.75 N, solid loading of 0.8% (w/v), temperature of 353 K and pretreatment time of 6 h and under these conditions, 40.2% delignification was obtained. In case of ultrasound-assisted alkaline approach, most favorable conditions obtained were alkali concentration of 1N, paper loading of 0.5% (w/v), sonication power of 100 W, duty cycle of 80% and pretreatment time of 70 min and the delignification obtained in ultrasound-assisted alkaline approach under these conditions was 80%. The material samples were characterized by FTIR, SEM, XRD and TGA technique. The lignin was recovered from solution by precipitation method and was characterized by FTIR, GPC and TGA technique. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Wild soybean roots depend on specific transcription factors and oxidation reduction related genesin response to alkaline stress. (United States)

    DuanMu, Huizi; Wang, Yang; Bai, Xi; Cheng, Shufei; Deyholos, Michael K; Wong, Gane Ka-Shu; Li, Dan; Zhu, Dan; Li, Ran; Yu, Yang; Cao, Lei; Chen, Chao; Zhu, Yanming


    Soil alkalinity is an important environmental problem limiting agricultural productivity. Wild soybean (Glycine soja) shows strong alkaline stress tolerance, so it is an ideal plant candidate for studying the molecular mechanisms of alkaline tolerance and identifying alkaline stress-responsive genes. However, limited information is available about G. soja responses to alkaline stress on a genomic scale. Therefore, in the present study, we used RNA sequencing to compare transcript profiles of G. soja root responses to sodium bicarbonate (NaHCO3) at six time points, and a total of 68,138,478 pairs of clean reads were obtained using the Illumina GAIIX. Expression patterns of 46,404 G. soja genes were profiled in all six samples based on RNA-seq data using Cufflinks software. Then, t12 transcription factors from MYB, WRKY, NAC, bZIP, C2H2, HB, and TIFY families and 12 oxidation reduction related genes were chosen and verified to be induced in response to alkaline stress by using quantitative real-time polymerase chain reaction (qRT-PCR). The GO functional annotation analysis showed that besides "transcriptional regulation" and "oxidation reduction," these genes were involved in a variety of processes, such as "binding" and "response to stress." This is the first comprehensive transcriptome profiling analysis of wild soybean root under alkaline stress by RNA sequencing. Our results highlight changes in the gene expression patterns and identify a set of genes induced by NaHCO3 stress. These findings provide a base for the global analyses of G. soja alkaline stress tolerance mechanisms.

  6. Heparin and alkalinized lidocaine versus alkalinized lidocaine for treatment of interstitial cystitis symptoms. (United States)

    Parsons, C Lowell; Koziol, James A; Proctor, Jeffrey G; Zupkas, Paul; Argade, Sulabha


    Interstitial cystitis (IC), sometimes referred to as IC/bladder pain syndrome, is a substantial health care problem. Once considered a rare, orphan disease, it is now believed to be relatively common. This pilot study was undertaken to determine if the combination of heparin and alkalinized lidocaine (heparin-lidocaine) was more efficacious than alkalinized lidocaine at relieving pain and urgency symptoms associated with IC and also capable of yielding higher lidocaine absorption. A single blind study was conducted on 14 IC patients with a heparin-lidocaine combination versus alkalinized lidocaine instilled intravesically. In a separate study serum lidocaine levels for heparin-alkalinized lidocaine combination versus USP lidocaine only were determined by high performance liquid chromatography. Alkalinized lidocaine and heparin have been reported to provide relief from pain and urgency symptoms associated with IC. The heparin-lidocaine combination significantly reduced the % of bladder pain (38% versus 13%, p = 0.029) and urgency (42% versus 8% p = 0.003) compared to lidocaine. In addition the GAR was significantly better for the heparin-lidocaine combination at both 1 hr % improved (77% versus 50%, p = 0.04) and 24 hrs (57% versus 23%, p = 0.002) after study drug treatment. Serum lidocaine levels for the heparin-lidocaine combination were significantly higher compared to USP lidocaine (unalkalinized). The mean +/- SEM was 0.45 +/- 0.09 µg/mL and 0.20 +/- 0.05 µg/mL, respectively (p = 0.019). In this pilot study the heparin-lidocaine combination results in significantly better relief of IC symptoms compared to alkalinized lidocaine and the combination yields higher lidocaine absorption than USP lidocaine.

  7. Temperature Dependence of Mineral Solubility in Water. Part 2. Alkaline and Alkaline Earth Bromides (United States)

    Krumgalz, B. S.


    Databases of alkaline and alkaline earth bromide solubilities in water at various temperatures were created using experimental data from publications over about the last two centuries. Statistical critical evaluation of the created databases was produced since there were enough independent data sources to justify such evaluation. The reliable experimental data were adequately described by polynomial expressions over various temperature ranges. Using the Pitzer approach for ionic activity and osmotic coefficients, the thermodynamic solubility products for the discussed bromide minerals have been calculated at various temperature intervals and also represented by polynomial expressions.

  8. Emission dynamics of In0.2Ga0.8As/GaAs λ and 2λ microcavity lasers (United States)

    Michler, P.; Hilpert, M.; Rühle, W. W.; Wolf, H. D.; Bernklau, D.; Riechert, H.


    We study the emission dynamics of two In0.2Ga0.8As/GaAs microcavity lasers after femtosecond optical excitation at 20 K. The pulse widths and the peak delays of λ and a 2λ cavity are compared. Pulses as short as 3.3 ps (9.5 ps) and peak delays as short as 8.2 ps (16.5 ps) are obtained with the 2λ cavity (λ cavity). The pulse widths and peak delays are well described by a model based on a rate equation analysis for carrier and photon densities; in particular, the better high speed characteristics of the 2λ cavity compared to the λ cavity are well reproduced.

  9. Deterministic photonic spatial-polarization hyper-controlled-not gate assisted by a quantum dot inside a one-side optical microcavity

    International Nuclear Information System (INIS)

    Ren, Bao-Cang; Wei, Hai-Rui; Deng, Fu-Guo


    To date, all work concerning the construction of quantum logic gates, an essential part of quantum computing, has focused on operating in one degree of freedom (DOF) for quantum systems. Here, we investigate the possibility of achieving scalable photonic quantum computing based on two DOFs for quantum systems. We construct a deterministic hyper-controlled-not (hyper-CNOT) gate operating in both the spatial mode and polarization DOFs for a photon pair simultaneously, using the giant optical Faraday rotation induced by a single-electron spin in a quantum dot inside a one-side optical microcavity as a result of cavity quantum electrodynamics. With this hyper-CNOT gate and linear optical elements, two-photon four-qubit cluster entangled states can be prepared and analyzed, which give an application to manipulate more information with less resources. We analyze the experimental feasibility of this hyper-CNOT gate and show that it can be implemented with current technology. (letter)

  10. Switching through symmetry breaking for transmission in a T-shaped photonic waveguide coupled with two identical nonlinear micro-cavities. (United States)

    Bulgakov, Evgeny; Sadreev, Almas


    Using coupled mode theory we consider transmission in a T-shaped waveguide coupled with two identical symmetrically positioned nonlinear micro-cavities with mirror symmetry. For input power injected into the central waveguide we show the existence of a symmetry breaking solution which is a result of mixing of the symmetrical input wave with an antisymmetric standing wave in the Fabry-Pérot interferometer. With growth of the input power, a feature in the form of loops arises in the solution which originates from bistability in the transmission in the output left/right waveguide coupled with the first/second nonlinear cavity. The domains of stability of the solution are found. The breaking of mirror symmetry gives rise to nonsymmetrical left and right outputs. We demonstrate that this phenomenon can be explored for all-optical switching of light transmission from the left output waveguide to the right one by application of input pulses.

  11. Net alkalinity and net acidity 2: Practical considerations (United States)

    Kirby, C.S.; Cravotta, C.A.


    The pH, alkalinity, and acidity of mine drainage and associated waters can be misinterpreted because of the chemical instability of samples and possible misunderstandings of standard analytical method results. Synthetic and field samples of mine drainage having various initial pH values and concentrations of dissolved metals and alkalinity were titrated by several methods, and the results were compared to alkalinity and acidity calculated based on dissolved solutes. The pH, alkalinity, and acidity were compared between fresh, unoxidized and aged, oxidized samples. Data for Pennsylvania coal mine drainage indicates that the pH of fresh samples was predominantly acidic (pH 2.5-4) or near neutral (pH 6-7); ??? 25% of the samples had pH values between 5 and 6. Following oxidation, no samples had pH values between 5 and 6. The Standard Method Alkalinity titration is constrained to yield values >0. Most calculated and measured alkalinities for samples with positive alkalinities were in close agreement. However, for low-pH samples, the calculated alkalinity can be negative due to negative contributions by dissolved metals that may oxidize and hydrolyze. The Standard Method hot peroxide treatment titration for acidity determination (Hot Acidity) accurately indicates the potential for pH to decrease to acidic values after complete degassing of CO2 and oxidation of Fe and Mn, and it indicates either the excess alkalinity or that required for neutralization of the sample. The Hot Acidity directly measures net acidity (= -net alkalinity). Samples that had near-neutral pH after oxidation had negative Hot Acidity; samples that had pH mine drainage treatment can lead to systems with insufficient Alkalinity to neutralize metal and H+ acidity and is not recommended. The use of net alkalinity = -Hot Acidity titration is recommended for the planning of mine drainage treatment. The use of net alkalinity = (Alkalinitymeasured - Aciditycalculated) is recommended with some cautions

  12. Persistently increased intestinal fraction of alkaline phosphatase

    DEFF Research Database (Denmark)

    Nathan, E; Baatrup, G; Berg, H


    Persistent elevation of the intestinal fraction of the alkaline phosphatase (API) as an isolated finding has to our knowledge not been reported previously. It was found in a boy followed during a period of 5.5 years. The only symptom was transient periodic fatigue observed at home, but not apparent...... during hospitalization. His blood type was O, RH+, Le (a-, b+) and he was a secretor of H-substance, which may be associated with rising API activity after fat-loading. In this case API was unchanged after fat-loading. Neither intestinal nor liver diseases were found, and no other cause for the elevated...

  13. Alkaline erosion of CR 39 polymer surfaces

    International Nuclear Information System (INIS)

    Faiman, Laurence


    We have investigated the mechanism of erosion of CR 39 polymer in alkaline environments. We observed the kinetics of absorption of water and methanol into both unirradiated and γ-irradiated samples. We use a capillary model to interpret our results. We etched our samples in both KOH solutions, and KOH solutions doped with methanol. Etch rate was desensitizing to γ-irradiation when KOH concentration approached saturation, but KOH solutions doped with methanol were not desensitizing, unlike with nuclear tracks. We account for this difference

  14. Alkaline carbonates in blast furnace process

    Directory of Open Access Journals (Sweden)

    P. Besta


    Full Text Available The production of iron in blast furnaces is a complex of physical, chemical and mechanical processes. The input raw materials contain not only metallic components, but also a number of negative elements. The most important negative elements include alkaline carbonates. They can significantly affect the course of the blast furnace process and thus the overall performance of the furnace. As a result of that, it is essential to accurately monitor the alkali content in the blast furnace raw materials. The article analyzes the alkali content in input and output raw materials and their impact on the blast furnace process.

  15. RES Hydrogen: efficient pressurised alkaline electrolysers

    DEFF Research Database (Denmark)

    Bowen, Jacob R.; Bentzen, Janet Jonna; Jørgensen, Peter Stanley

    The RESelyser project addresses issues associated with coupling alkaline electrolysis to renewable energy sources such as electrode stability and gas purity by implementing improved electrodes and a new separator membrane concept. The project aims to improve performance, operation pressure...... and reduce system cost. The project supports DTU Energy's activities on electrodes within the larger FCH-JU project. The overall project demonstrated: improved electrode efficiency also during cyclic operation, safe gas purity at a system pressure of 30 bar, 10 kW stack operation and estimated system costs...

  16. Net alkalinity and net acidity 2: Practical considerations (United States)

    Kirby, C.S.; Cravotta, C.A.


    The pH, alkalinity, and acidity of mine drainage and associated waters can be misinterpreted because of the chemical instability of samples and possible misunderstandings of standard analytical method results. Synthetic and field samples of mine drainage having various initial pH values and concentrations of dissolved metals and alkalinity were titrated by several methods, and the results were compared to alkalinity and acidity calculated based on dissolved solutes. The pH, alkalinity, and acidity were compared between fresh, unoxidized and aged, oxidized samples. Data for Pennsylvania coal mine drainage indicates that the pH of fresh samples was predominantly acidic (pH 2.5-4) or near neutral (pH 6-7); ??? 25% of the samples had pH values between 5 and 6. Following oxidation, no samples had pH values between 5 and 6. The Standard Method Alkalinity titration is constrained to yield values >0. Most calculated and measured alkalinities for samples with positive alkalinities were in close agreement. However, for low-pH samples, the calculated alkalinity can be negative due to negative contributions by dissolved metals that may oxidize and hydrolyze. The Standard Method hot peroxide treatment titration for acidity determination (Hot Acidity) accurately indicates the potential for pH to decrease to acidic values after complete degassing of CO2 and oxidation of Fe and Mn, and it indicates either the excess alkalinity or that required for neutralization of the sample. The Hot Acidity directly measures net acidity (= -net alkalinity). Samples that had near-neutral pH after oxidation had negative Hot Acidity; samples that had pH calculated based on initial pH and dissolved concentrations of Fe, Mn, and Al minus the initial alkalinity. Acidity calculated from the pH and dissolved metals concentrations, assuming equivalents of 2 per mole of Fe and Mn and 3 per mole of Al, was equivalent to that calculated based on complete aqueous speciation of FeII/FeIII. Despite changes in

  17. Neutral alkaline-metal and alkaline-earth-metal derivatives of imidazole and benzimidazole. (United States)

    Blanco, Fernando; Lloyd, David G; Alkorta, Ibon; Elguero, José


    A theoretical study of the minima and connecting transition states of the neutral complexes formed by alkaline-metal and alkaline-earth-metal derivatives of imidazolate and benzimidazolate anions has been carried out using B3LYP/6-31+G(d,p), B3LYP/6-311+G(3df,2p), and G3B3 methods. Two and three nondegenerated minima and two and four TS structures have been identified for imidazole and benzimidazole derivatives, respectively. The most stable minima of the alkaline-metal derivatives of both systems correspond to the metal interacting with the imidazole ring, whereas in the alkaline-earth-metal derivatives, the preferred minima depend on the substituent. A remarkable feature of some minima is the fact that some of the metal-aromatic interactions follow the classical π-cation pattern, even though the global structure corresponds to a neutral salt, constituting a class of noncovalent interaction of great interest in the chemistry of aromatic and heterocyclic complexes. A CSD search has confirmed that the two bonding modes, N-σ and π, are present in the solid phase. The π mode has been analyzed by comparison with other azoles.

  18. Alkaline chemistry of transuranium elements and technetium and the treatment of alkaline radioactive wastes

    Energy Technology Data Exchange (ETDEWEB)

    Delegard, C.H. [Westinghouse Hanford Co., Richland, WA (United States); Peretrukhin, V.F.; Shilov, V.P.; Pikaev, A.K. [Russian Academy of Sciences (Russian Federation). Inst. of Physical Chemistry


    Goal of this survey is to generalize the known data on fundamental physical-chemical properties of TRUs and Tc, methods for their isolation, and to provide recommendations that will be useful for partitioning them from alkaline high-level wastes.

  19. Alkaline chemistry of transuranium elements and technetium and the treatment of alkaline radioactive wastes

    International Nuclear Information System (INIS)

    Delegard, C.H.; Peretrukhin, V.F.; Shilov, V.P.; Pikaev, A.K.


    Goal of this survey is to generalize the known data on fundamental physical-chemical properties of TRUs and Tc, methods for their isolation, and to provide recommendations that will be useful for partitioning them from alkaline high-level wastes

  20. Handbook of optical microcavities

    CERN Document Server

    Choi, Anthony H W


    An optical cavity confines light within its structure and constitutes an integral part of a laser device. Unlike traditional gas lasers, semiconductor lasers are invariably much smaller in dimensions, making optical confinement more critical than ever. In this book, modern methods that control and manipulate light at the micrometer and nanometer scales by using a variety of cavity geometries and demonstrate optical resonance from ultra-violet (UV) to infra-red (IR) bands across multiple material platforms are explored. The book has a comprehensive collection of chapters that cover a wide range

  1. Activation of Alkaline Irrigation Fluids in Endodontics. (United States)

    Walsh, Laurence J; George, Roy


    In conventional endodontic treatment, alkaline solutions of sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA) are used in combination to disinfect the root canal system and to eliminate debris and smear layers. An important concept that has emerged over recent years is the use of active physical methods for agitating these fluids to improve their penetration within areas that are not reached by endodontic instruments and to accelerate the chemical actions of these alkaline fluids against planktonic microorganisms, biofilms, soft tissue remnants and smear layers. Ultrasonic agitation and more recently pulsed lasers have emerged as two promising methods for activating endodontic irrigation fluids. Ultrasonic agitation with piezoelectric devices employs a moving tip, while laser agitation uses a stationary tip. Both methods cause cavitation, followed by implosions and shear forces which assist with debridement. Fluid streaming further enhances the activity of the fluids. While agitation enhances performance of irrigants, extrusion of fluids from the root canal during activation is a hazard that must be controlled.

  2. High temperature and pressure alkaline electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Ganley, Jason C. [Department of Chemical Engineering, Howard University, 2013 Lewis K. Downing Hall, 2300 6th Street NW, Washington, DC 20059 (United States)


    This paper describes experimental work involving the direct-current electrolysis of highly concentrated potassium hydroxide solutions at high temperatures (up to 400 C) and under various pressures. A high-temperature alkaline electrolysis cell resistant to chemical attack from the highly corrosive electrolyte solution and capable of high-pressure operation was designed and tested. The cell was constructed with a Monel {sup registered} alloy housing and cathode, while various anode materials were compared. The anode materials tested included nickel, Monel alloy, lithiated nickel, and cobalt-plated nickel. The advantages of operating an alkaline electrolysis cell at high temperatures include increasing the ionic conductivity of the electrolyte and enhancing the rates of electrochemical reactions at the electrode surfaces. Cell operation with increasing steam partial pressure over the solution is also shown to enhance cell performance. The prudent selection of anode material also impacts the required terminal potential for a given current density, and consequently the cell's electric power efficiency. The best cell performance was achieved using a cobalt-plated nickel anode at a temperature of 400 C and a steam partial pressure of 8.7 MPa. (author)

  3. Activation of Alkaline Irrigation Fluids in Endodontics (United States)

    George, Roy


    In conventional endodontic treatment, alkaline solutions of sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA) are used in combination to disinfect the root canal system and to eliminate debris and smear layers. An important concept that has emerged over recent years is the use of active physical methods for agitating these fluids to improve their penetration within areas that are not reached by endodontic instruments and to accelerate the chemical actions of these alkaline fluids against planktonic microorganisms, biofilms, soft tissue remnants and smear layers. Ultrasonic agitation and more recently pulsed lasers have emerged as two promising methods for activating endodontic irrigation fluids. Ultrasonic agitation with piezoelectric devices employs a moving tip, while laser agitation uses a stationary tip. Both methods cause cavitation, followed by implosions and shear forces which assist with debridement. Fluid streaming further enhances the activity of the fluids. While agitation enhances performance of irrigants, extrusion of fluids from the root canal during activation is a hazard that must be controlled. PMID:29065540

  4. Activation of Alkaline Irrigation Fluids in Endodontics

    Directory of Open Access Journals (Sweden)

    Laurence J. Walsh


    Full Text Available In conventional endodontic treatment, alkaline solutions of sodium hypochlorite (NaOCl and ethylenediaminetetraacetic acid (EDTA are used in combination to disinfect the root canal system and to eliminate debris and smear layers. An important concept that has emerged over recent years is the use of active physical methods for agitating these fluids to improve their penetration within areas that are not reached by endodontic instruments and to accelerate the chemical actions of these alkaline fluids against planktonic microorganisms, biofilms, soft tissue remnants and smear layers. Ultrasonic agitation and more recently pulsed lasers have emerged as two promising methods for activating endodontic irrigation fluids. Ultrasonic agitation with piezoelectric devices employs a moving tip, while laser agitation uses a stationary tip. Both methods cause cavitation, followed by implosions and shear forces which assist with debridement. Fluid streaming further enhances the activity of the fluids. While agitation enhances performance of irrigants, extrusion of fluids from the root canal during activation is a hazard that must be controlled.

  5. Spectroscopic characterization of alkaline earth uranyl carbonates

    International Nuclear Information System (INIS)

    Amayri, Samer; Reich, Tobias; Arnold, Thuro; Geipel, Gerhard; Bernhard, Gert


    A series of alkaline uranyl carbonates, M[UO 2 (CO 3 ) 3 ].nH 2 O (M=Mg 2 , Ca 2 , Sr 2 , Ba 2 , Na 2 Ca, and CaMg) was synthesized and characterized by inductively coupled plasma mass spectrometry (ICP-MS) and atomic absorption spectrometry (AAS) after nitric acid digestion, X-ray powder diffraction (XRD), and thermal analysis (TGA/DTA). The molecular structure of these compounds was characterized by extended X-ray absorption fine-structure (EXAFS) spectroscopy and X-ray photoelectron spectroscopy (XPS). Crystalline Ba 2 [UO 2 (CO 3 ) 3 ].6H 2 O was obtained for the first time. The EXAFS analysis showed that this compound consists of (UO 2 )(CO 3 ) 3 clusters similar to the other alkaline earth uranyl carbonates. The average U-Ba distance is 3.90+/-0.02A.Fluorescence wavelengths and life times were measured using time-resolved laser-induced fluorescence spectroscopy (TRLFS). The U-O bond distances determined by EXAFS, TRLFS, XPS, and Raman spectroscopy agree within the experimental uncertainties. The spectroscopic signatures observed could be useful for identifying uranyl carbonate species adsorbed on mineral surfaces


    Energy Technology Data Exchange (ETDEWEB)



    Physical and chemical agents in the environment, those used in clinical applications, or encountered during recreational exposures to sunlight, induce damages in DNA. Understanding the biological impact of these agents requires quantitation of the levels of such damages in laboratory test systems as well as in field or clinical samples. Alkaline gel electrophoresis provides a sensitive (down to {approx} a few lesions/5Mb), rapid method of direct quantitation of a wide variety of DNA damages in nanogram quantities of non-radioactive DNAs from laboratory, field, or clinical specimens, including higher plants and animals. This method stems from velocity sedimentation studies of DNA populations, and from the simple methods of agarose gel electrophoresis. Our laboratories have developed quantitative agarose gel methods, analytical descriptions of DNA migration during electrophoresis on agarose gels (1-6), and electronic imaging for accurate determinations of DNA mass (7-9). Although all these components improve sensitivity and throughput of large numbers of samples (7,8,10), a simple version using only standard molecular biology equipment allows routine analysis of DNA damages at moderate frequencies. We present here a description of the methods, as well as a brief description of the underlying principles, required for a simplified approach to quantitation of DNA damages by alkaline gel electrophoresis.

  7. Stability and activity profile of alkaline protease produced from bacillus subtilis

    International Nuclear Information System (INIS)

    Anjum, S.; Mukhtar, H.; Nawaz, A.; Haq, I.U.


    The present study gives an insight into the effect of different activators and inhibitors on the activity and stability of alkaline proteases produced by Bacillus subtilis IH-72. The alkaline protease was strongly activated both by bivalent and monovalent cations such as Mg/sup 2+/, Mn/sup 2+/, Na/sup +/ and K/sup +/. The enzyme activity was considerably enhanced in the presence of fructose, galactose, glucose and mannitol. The enzyme was stabilized up to 10 days by immobilization on activated charcoal and was efficiently stabilized up to 2 months by lyophilization. The enzyme remained stable up to 19 days both at 4 degree C and 30 degree C in the presence of Mn/sup 2+/. However, it exhibited significant stability up to 22 days at 4 degree C and 30 degree C in the presence of fructose, galactose and polyethylene glycol. (author)

  8. Effects of aluminum on plasma membrane as revealed by analysis of alkaline band formation in internodal cells of Chara corallina. (United States)

    Takano, M; Shimmen, T


    To study the mechanism of aluminum toxicity in plant cells, the effects of aluminum on alkaline band formation were analyzed in the internodal cells of Chara. After cells were treated with AlCl3, they were examined for their capacity to develop alkaline bands. Treating cells with AlCl3 medium at pH 4.5 completely inhibited alkaline band formation. When either CaCl2 or malic acid was added to the AlCl3 medium (pH 4.5), it did not produce an ameliorative effect, whereas addition of both CaCl2 and malic acid induced a significant ameliorative effect. It was found that treatment at pH 4.5 in the absence of AlCl3 strongly inhibited alkaline band formation. This inhibition by the low pH (4.5) treatment was effectively ameliorated by CaCl2. At higher pH (5.0), malic acid alone produced a significant ameliorative effect on aluminum inhibition of alkaline band formation, but CaCl2 did not. Recovery from aluminum inhibition was also studied. When cells treated with AlCl3 at pH 4.5 were incubated in artificial pond water, they could not recover the capacity to develop alkaline band. When either malic acid or CaCl2 was added to artificial pond water, cells recovered their alkaline band formation. It was concluded that one of the primary targets of aluminum is the plasma membrane and that aluminum affects the plasma membrane from the cell exterior at the beginning of the treatment (within 24 h). It was also suggested that the aluminum treatment impairs the HCO3- influx mechanism but not the OH- efflux mechanism.

  9. Alkaline lixiviation of uranium in granitic pegmatite

    International Nuclear Information System (INIS)

    Jambor, S.


    The work described herein concerns the determination of the experimental optimum conditions for the alkaline lixiviation of uranium based on the following parameters: time, pH, temperature, density and grane size. The samples were obtained from the Supamo complex, near the Currupia river in the Piar District of the Bolivar State in Venezuela. They have a granitic composition and graphitic texture. The uranium was found in them as a secondary oxidized mineral of green-yellow colour localized in fractures fissures, intergranular spaces and also in the mica as. Secondary uranitite. The lixiviation process was carried out using Na 2 CO 3 /NaHCO 3 buffer solution and for 100 gr. samples the best values for an efficient process were found by using 170 mesh grane size and 500 ml of pH buffer at 70 0 C for a 24 hour time period. (author)

  10. Properties of cathode materials in alkaline cells

    International Nuclear Information System (INIS)

    Salkind, A.J.; McBreen, J.; Freeman, R.; Parkhurst, W.A.


    Conventional and new cathode materials in primary and secondary alkaline cells were investigated for stability, structure, electrochemical reversibility and efficiency. Included were various forms of AgO for reserve-type silver-zinc batteries, a new material - AgNiO/sub 2/ - and several nickel electrodes for nickel-cadmium and nickel-hydrogen cells for aerospace applications. A comparative study was made of the stability of electroformed and chemically prepared AgO. Stability was correlated with impurities detected by XPS and SAM. After the first discharge AgNiO/sub 2/ can be recharged to the monovalent level. The discharge product is predominantly silver. Plastic-bonded nickel electrodes display a second plateau on discharge. Additions of Co(OH)/sub 2/ largely eliminate this

  11. Alkaline pulping of some eucalypts from Sudan. (United States)

    Khristova, P; Kordsachia, O; Patt, R; Dafaalla, S


    Four eucalypts (Eucalyptus camaldulensis, Eucalyptus microtheca, Eucalyptus tereticornis and Eucalyptus citriodora) grown in Sudan were examined for their suitability for pulping and papermaking with different alkaline methods. Their physical, morphological and chemical characteristics are reported. The pulping trials with E. citriodora and E. tereticornis were carried out using the kraft-AQ, soda-AQ, modified AS/AQ (ASA), ASAM and kraft methods. For the other two species, only the ASAM and the kraft process were applied. ASAM pulping gave the best results in terms of yield, degree of delignification, mechanical and optical pulp properties. The best pulps, obtained in kraft and ASAM cooking of E. citriodora, were bleached to 88% ISO brightness in a totally chlorine free bleaching sequence (OQ1O/PQ2P). The bleached pulps, especially the ASAM pulp, showed good papermaking properties and would be suitable for manufacture of writing and printing grades of paper.

  12. Retention of alkaline earth elements in man

    International Nuclear Information System (INIS)

    Newton, D.


    The data on human metabolism and long-term retention of alkaline earth elements ( 133 Ba injected into six healthy male volunteers at age 25-81 y and 45 Ca and 85 Sr received by one healthy male volunteer) are presented. Excreta were collected for 2-3 weeks after injection of the tracer into an antecubital vein. Activity in urine, ashed faeces and early samples of blood plasma was determined by gamma-ray scintillation spectrometry. Whole body retention has been assessed through serial measurements of body radioactivity. The injected 133 Ba apparently became mainly skeletal within several days, much earlier than predicted by the ICRP model. The whole-body retention at 32 d ranged from 5 to 14%, the rate of loss correlating with the excretory plasma clearance rate. No age-related trends were identified in the metabolism of Ca and Sr. 2 refs, 2 figs

  13. Properties of cathode materials in alkaline cells (United States)

    Salkind, A. J.; McBreen, J.; Freeman, R.; Parkhurst, W. A.


    Conventional and new cathode materials in primary and secondary alkaline cells were investigated for stability, structure, electrochemical reversibility and efficiency. Included were various forms of AgO for reserve type silver zinc batteries, a new material - AgNiO2 and several nickel electrodes for nickel cadmium and nickel hydrogen cells for aerospace applications. A comparative study was made of the stability of electroformed and chemically prepared AgO. Stability was correlated with impurities. After the first discharge AgNiO2 can be recharged to the monovalent level. The discharge product is predominantly silver. Plastic bonded nickel electrodes display a second plateau on discharge. Additions of Co(OH)2 largely eliminate this.

  14. Aluminum corrosion mitigation in alkaline electrolytes containing hybrid inorganic/organic inhibitor system for power sources applications (United States)

    Gelman, Danny; Lasman, Itay; Elfimchev, Sergey; Starosvetsky, David; Ein-Eli, Yair


    The severe corrosion accompanied with hydrogen evolution process is the main obstacle preventing the implementation of Al as an anode in alkaline batteries. It impairs the functionality of alkaline battery, due to a drastic capacity loss and a short shelf life. The possibility to reduce Al corrosion rate in alkaline solution with the use of hybrid organic∖inorganic inhibitor based on poly (ethylene glycol) di-acid (PEG di-acid) and zinc oxide (ZnO) was examined in this work. A correlation between an Al corrosion rates and the concentrations of both PEG di-acid and ZnO in alkaline is shown. Selecting 5000 ppm PEG di-acid and 16 gr/l ZnO provides substantial corrosion protection of Al, reducing the corrosion rate in a strong alkaline solution by more than one order of magnitude. Moreover, utilizing the same formulation results in increase in Al-air battery discharge capacity, from 44.5 (for a battery utilizing only KOH in the electrolyte) to 70 mhA/cm2 (for a battery utilizing ZnO/PEG di-acid hybrid inhibitor in the electrolyte). The morphology and composition of the Al electrode surface (studied by SEM, EDS, and XRD) depend on PEG di-acid and ZnO concentrations.

  15. Engineering light emission of two-dimensional materials in both the weak and strong coupling regimes (United States)

    Brotons-Gisbert, Mauro; Martínez-Pastor, Juan P.; Ballesteros, Guillem C.; Gerardot, Brian D.; Sánchez-Royo, Juan F.


    Two-dimensional (2D) materials have promising applications in optoelectronics, photonics, and quantum technologies. However, their intrinsically low light absorption limits their performance, and potential devices must be accurately engineered for optimal operation. Here, we apply a transfer matrix-based source-term method to optimize light absorption and emission in 2D materials and related devices in weak and strong coupling regimes. The implemented analytical model accurately accounts for experimental results reported for representative 2D materials such as graphene and MoS2. The model has been extended to propose structures to optimize light emission by exciton recombination in MoS2 single layers, light extraction from arbitrarily oriented dipole monolayers, and single-photon emission in 2D materials. Also, it has been successfully applied to retrieve exciton-cavity interaction parameters from MoS2 microcavity experiments. The present model appears as a powerful and versatile tool for the design of new optoelectronic devices based on 2D semiconductors such as quantum light sources and polariton lasers.

  16. Enzymatic Hydrolysis of Alkaline Pretreated Coconut Coir

    Directory of Open Access Journals (Sweden)

    Akbarningrum Fatmawati


    Full Text Available The purpose of this research is to study the effect of concentration and temperature on the cellulose and lignin content, and the reducing sugars produced in the enzymatic hydrolysis of coconut coir. In this research, the coconut coir is pretreated using 3%, 7%, and 11% NaOH solution at 60oC, 80oC, and 100oC. The pretreated coir were assayed by measuring the amount of cellulose and lignin and then hydrolysed using Celluclast and Novozyme 188 under various temperature (30oC, 40oC, 50oC and pH (3, 4, 5. The hydrolysis results were assayed for the reducing sugar content. The results showed that the alkaline delignification was effective to reduce lignin and to increase the cellulose content of the coir. The best delignification condition was observed at 11% NaOH solution and 100oC which removed 14,53% of lignin and increased the cellulose content up to 50,23%. The best condition of the enzymatic hydrolysis was obtained at 50oC and pH 4 which produced 7,57 gr/L reducing sugar. © 2013 BCREC UNDIP. All rights reservedReceived: 2nd October 2012; Revised: 31st January 2013; Accepted: 6th February 2013[How to Cite: Fatmawati, A., Agustriyanto, R., Liasari, Y. (2013. Enzymatic Hydrolysis of Alkaline Pre-treated Coconut Coir. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (1: 34-39 (doi:10.9767/bcrec.8.1.4048.34-39[Permalink/DOI:] | View in  |

  17. Precision measurement of single atoms strongly coupled to the higher-order transverse modes of a high-finesse optical cavity

    Energy Technology Data Exchange (ETDEWEB)

    Du, Jinjin; Li, Wenfang; Wen, Ruijuan; Li, Gang; Zhang, Pengfei; Zhang, Tiancai [State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006 (China)


    We have experimentally demonstrated the strong coupling between single atoms and the higher-order Hermite-Gaussian transverse modes in a high-finesse optical microcavity. Compared to the usual low-order symmetric transverse modes, multiple lobes and the asymmetric spatial pattern of the titled modes provide more information about the motion of single atoms in the cavity. The motional information can be extracted from the measured transmission spectra, which includes the velocities and the positions of the atoms in vertical and off-axis directions. The scheme has great potential in time-resolved atom-cavity microscopy and in tracking the three-dimensional single atom trajectory in real time.

  18. Temperature measurement of cold atoms using single-atom transits and Monte Carlo simulation in a strongly coupled atom-cavity system

    Energy Technology Data Exchange (ETDEWEB)

    Li, Wenfang; Du, Jinjin; Wen, Ruijuan; Yang, Pengfei; Li, Gang; Zhang, Tiancai, E-mail: [State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006 (China); Liang, Junjun [Department of Physics, Shanxi University, Taiyuan 030006 (China)


    We investigate the transmission of single-atom transits based on a strongly coupled cavity quantum electrodynamics system. By superposing the transit transmissions of a considerable number of atoms, we obtain the absorption spectra of the cavity induced by single atoms and obtain the temperature of the cold atom. The number of atoms passing through the microcavity for each release is also counted, and this number changes exponentially along with the atom temperature. Monte Carlo simulations agree closely with the experimental results, and the initial temperature of the cold atom is determined. Compared with the conventional time-of-flight (TOF) method, this approach avoids some uncertainties in the standard TOF and sheds new light on determining temperature of cold atoms by counting atoms individually in a confined space.

  19. Enhanced oil recovery using local alkaline | Akpoturi | Nigerian ...

    African Journals Online (AJOL)

    The efficiency of the local alkaline (palm bunch ash) was compared with other conventional alkaline (NaOH, KOH, and Na2CO3). Eight cores (A1 – A$ and C1 – C4) were prepared, saturated with formation brine of 30, 000ppm salinity; crude (light and medium) were then flowed through sand samples. The samples were ...

  20. Waterbirds of alkaline lakes in Western Uganda | Pomeroy | Journal ...

    African Journals Online (AJOL)

    Uganda's only alkaline lakes are found in the Queen Elizabeth Conservation Area and the adjoining Kyambura Wildlife Reserve. Both are Important Bird Areas, a status to which the birds of the lakes contribute. A total of 179 waterbird counts were made between 1984 and 2000, covering eight of the nine alkaline lakes, ...

  1. based anion exchange membrane for alkaline polymer electrolyte

    Indian Academy of Sciences (India)


    Alkaline polymer electrolyte fuel cell; anion exchange membrane; PPO; homogeneous quaterni- zation. 1. Introduction. Presently, alkaline polymer electrolyte fuel cells (APEFCs) using anion exchange membranes have received an immense interest among researchers (Varcoe and Slade. 2005). The advantages of ...

  2. Dynamic Properties of the Alkaline Vesicle Population at Hippocampal Synapses (United States)

    Röther, Mareike; Brauner, Jan M.; Ebert, Katrin; Welzel, Oliver; Jung, Jasmin; Bauereiss, Anna; Kornhuber, Johannes; Groemer, Teja W.


    In compensatory endocytosis, scission of vesicles from the plasma membrane to the cytoplasm is a prerequisite for intravesicular reacidification and accumulation of neurotransmitter molecules. Here, we provide time-resolved measurements of the dynamics of the alkaline vesicle population which appears upon endocytic retrieval. Using fast perfusion pH-cycling in live-cell microscopy, synapto-pHluorin expressing rat hippocampal neurons were electrically stimulated. We found that the relative size of the alkaline vesicle population depended significantly on the electrical stimulus size: With increasing number of action potentials the relative size of the alkaline vesicle population expanded. In contrast to that, increasing the stimulus frequency reduced the relative size of the population of alkaline vesicles. Measurement of the time constant for reacification and calculation of the time constant for endocytosis revealed that both time constants were variable with regard to the stimulus condition. Furthermore, we show that the dynamics of the alkaline vesicle population can be predicted by a simple mathematical model. In conclusion, here a novel methodical approach to analyze dynamic properties of alkaline vesicles is presented and validated as a convenient method for the detection of intracellular events. Using this method we show that the population of alkaline vesicles is highly dynamic and depends both on stimulus strength and frequency. Our results implicate that determination of the alkaline vesicle population size may provide new insights into the kinetics of endocytic retrieval. PMID:25079223

  3. Alkaline protease production on date waste by an alkalophilic ...

    African Journals Online (AJOL)

    This research focused on isolation and characterization of a new strain of Bacillus sp. from alkaline soil, which was able to producing extracellular alkaline protease and amylase from date waste at pH ranging from 8 to 11 and temperatures of 20 to 50°C. Purification was conducted by fractionation, concentration, and cation ...

  4. A generally applicable sequential alkaline phosphatase immunohistochemical double staining

    NARCIS (Netherlands)

    van der Loos, Chris M.; Teeling, Peter


    A universal type of sequential double alkaline phosphatase immunohistochemical staining is described that can be used for formalin-fixed, paraffin-embedded and cryostat tissue sections from human and mouse origin. It consists of two alkaline phosphatase detection systems including enzymatic

  5. Partial purification and characterization of alkaline proteases from ...

    African Journals Online (AJOL)

    Alkaline proteases from the digestive tract of anchovy were partially purified by ammonium sulfate fractionation, dialysis and Sephadex G-75 gel filtration. The purification fold and yield were 6.23 and 4.49%, respectively. The optimum activities of partially purified alkaline proteases were observed at 60°C and at pH 11.0.

  6. Comparative Detection of Alkaline Protease Production in Exiguobacterium acetylicum

    International Nuclear Information System (INIS)

    Gomaa, O.M.; EI Shafey, H.M.


    Alkaline protease is one of the most important enzymes in industry, medicine, and research. In the present work, a comparative detection for alkaline protease activity was established for instant detection of enzyme activity. Eight different alkalophilic bacterial isolates were compared based on the clear zone they produced on skim milk agar. One strain gave an absolute clear zone in 16 hours and was used for alkaline protease detection. The result of Phenotypic identification using Biology Microlog 3 identified the isolate as Exiguobacterium acetylicum. The isolate under study showed slightly different characteristics from a known Exiguobacterium acetylicum strain. The isolate tolerated alkaline conditions up to ph 11, while good growth was evident at ph 7, the maximum alkaline protease activity was observed at ph 9 which reached up to 109.01 U/ml. The alkaline activity assay using alkaline protease enzyme assay were coordinating with those obtained by conductivity; there was a relevant decrease in conductivity at the maximum increase in enzyme activity, which proved the cell membrane conductivity has a close relation to alkaline protease production. This isolate has tolerated gamma radiation, the increase in dose (up to 4 Gy) gave wider clear zones in terms of diameter and this was relevant to the conductivity measurements

  7. Application of alkaline waterflooding to a high acidity crude oil

    Energy Technology Data Exchange (ETDEWEB)

    Sayyouh, M.H. (King Sand Univ., Riyadh (SA). Petroleum Engineering Dept.); Abdel-Waly, A.; Osman, A. (Cairo Univ. (EG). Petroleum Engineering Dept.); Awara, A.Z. (Geisum Oil Company, Cairo (EG))

    The enhanced recovery of a high acidity crude oil (South Geisum crude) by alkaline solutions is studied. Acidity, interfacial tension, and contact angle, were investigated. Displacement tests were carried out to study the effect of alkaline slug concentration, slug size, oil alkali type, temperature and viscosity on recovery. The interfacial tension between crude oil and formation water decreases with increasing alkaline concentration until a minimum, after which it increases again. Contact angle measurements indicated oil-wetting conditions that increase by the addition of alkaline solutions. At the early stages of displacement, oil recovery increases with increasing alkaline concentration until a maximum at 4% by weight NaOH concentration. Also, at such early stages, an excessive increase in alkaline concentration results in lower oil recovery. On the other hand, after the injection of many pore volumes of water, oil recovery is almost the same regardless of the alkaline concentration. Oil recovery increases with increasing alkaline slug size until a maximum at 15% PV. Sodium hydroxide slugs produce more oil recovery than sodium carbonate slugs. Oil recovery increases with increasing temperature (from 25 to 55{sup 0}C) and decreasing oil viscosity.

  8. Production of Thermostab Streptomyc ction of Thermostable Alkaline ...

    African Journals Online (AJOL)

    Correspondence: Introduction. Proteases are enzymes that catalyze the hydrolysis of protein into amino-acid. Proteases, especially alkaline type constitute about 60-65% of the global industrial enzyme market (Gupta et al., 2010). Among different proteases, alkaline proteases produced by.

  9. Production of alkaline protease by Teredinobacter turnirae cells ...

    African Journals Online (AJOL)

    The conditions for immobilizing the new alkaline protease-producing bacteria strain Teredinobacter turnirae by entrapment in calcium alginate gel were investigated. The influence of alginate concentration (20, 25 and 30 g/l) and initial cell loading (ICL) on enzyme production were studied. The production of alkaline ...

  10. Purification and characterization of an alkaline protease from Micrococcus sp. isolated from the South China Sea (United States)

    Hou, Enling; Xia, Tao; Zhang, Zhaohui; Mao, Xiangzhao


    Protease is wildly used in various fields, such as food, medicine, washing, leather, cosmetics and other industrial fields. In this study, an alkaline protease secreted by Micrococcus NH54PC02 isolated from the South China Sea was purified and characterized. The growth curve and enzyme activity curve indicated that the cell reached a maximum concentration at the 30th hour and the enzyme activity reached the maximum value at the 36th hour. The protease was purified with 3 steps involving ammonium sulfate precipitation, ion-exchange chromatography and hydrophobic chromatography with 8.22-fold increase in specific activity and 23.68% increase in the recovery. The molecular mass of the protease was estimated to be 25 kDa by SDS-PAGE analysis. The optimum temperature and pH for the protease activity were 50°C and pH 10.0, respectively. The protease showed a strong stability in a wide range of pH values ranging from 6.0-11.0, and maintained 90% enzyme activity in strong alkaline environment with pH 11.0. Inhibitor trials indicated that the protease might be serine protease. But it also possessed the characteristic of metalloprotease as it could be strongly inhibited by EDTA and strongly stimulated by Mn2+. Evaluation of matrix-assisted laser desorption ionization/time-of-flight MS (MALDI-TOF-TOF/MS) showed that the protease might belong to the peptidase S8 family.

  11. Reversible Hydrolysis Reaction with the Spore Photoproduct under Alkaline Conditions. (United States)

    Adhikari, Surya; Lin, Gengjie; Li, Lei


    DNA lesions may reduce the electron density at the nucleobases, making them prone to further modifications upon the alkaline treatment. The dominant DNA photolesion found in UV-irradiated bacterial endospores is a thymine dimer, 5-thyminyl-5,6-dihydrothymine, i.e., the spore photoproduct (SP). Here we report a stepwise addition/elimination reaction in the SP hydrolysis product under strong basic conditions where a ureido group is added to the carboxyl moiety to form a cyclic amide, regenerating SP after eliminating a hydroxide ion. Direct amidation of carboxylic acids by reaction with amines in the presence of a catalyst is well documented; however, it is very rare for an amidation reaction to occur without activation. This uncatalyzed SP reverse reaction in aqueous solution is even more surprising because the carboxyl moiety is not a good electrophile due to the negative charge it carries. Examination of the base-catalyzed hydrolyses of two other saturated pyrimidine lesions, 5,6-dihydro-2'-deoxyuridine and pyrimidine (6-4) pyrimidone photoproduct, reveals that neither reaction is reversible even though all three hydrolysis reactions may share the same gem-diol intermediate. Therefore, the SP structure where the two thymine residues maintain a stacked conformation likely provides the needed framework enabling this highly unusual carboxyl addition/elimination reaction.

  12. Ethanol production from bamboo using mild alkaline pre-extraction followed by alkaline hydrogen peroxide pretreatment. (United States)

    Yuan, Zhaoyang; Wen, Yangbing; Kapu, Nuwan Sella


    A sequential two-stage pretreatment process comprising alkaline pre-extraction and alkaline hydrogen peroxide pretreatment (AHP) was investigated to convert bamboo carbohydrates into bioethanol. The results showed that mild alkaline pre-extraction using 8% (w/w) sodium hydroxide (NaOH) at 100°C for 180min followed by AHP pretreatment with 4% (w/w) hydrogen peroxide (H 2 O 2 ) was sufficient to generate a substrate that could be efficiently digested with low enzyme loadings. Moreover, alkali pre-extraction enabled the use of lower H 2 O 2 charges in AHP treatment. Two-stage pretreatment followed by enzymatic hydrolysis with only 9FPU/g cellulose led to the recovery of 87% of the original sugars in the raw feedstock. The use of the pentose-hexose fermenting Saccharomyces cerevisiae SR8u strain enabled the utilization of 95.7% sugars in the hydrolysate to reach 4.6%w/v ethanol titer. The overall process also enabled the recovery of 62.9% lignin and 93.8% silica at high levels of purity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Geochemical modeling of the influence of silicate mineral alteration on alkalinity production and carbonate precipitation (United States)

    Herda, Gerhard; Kraemer, Stephan M.; Gier, Susanne; Meister, Patrick


    High CO2 partial pressure (pCO2) in deep rock reservoirs causes acidification of the porefluid. Such conditions occur during injection and subsurface storage of CO2 (to prevent the release of greenhouse gas) but also naturally in zones of strong methanogenic microbial activity in organic matter-rich ocean margin sediments. The acidic fluids are corrosive to carbonates and bear the risk of leakage of CO2 gas to the surface. Porefluid acidification may be moderated by processes that increase the alkalinity, i.e. that produce weak acid anions capable of buffering the acidification imposed by the CO2. Often, alkalinity increases as a result of anaerobic microbial activity, such as anaerobic oxidation of methane. However, on a long term the alteration of silicates, in particular, clay minerals, may be a more efficient mechanism of alkalinity production. Under altered temperature, pressure and porefluid composition at depth, clay minerals may change to thermodynamically more stable states, thereby increasing the alkalinity of the porefluid by partial leaching of Mg-(OH)2 and Ca-(OH)2 (e.g. Wallmann et al., 2008; Mavromatis et al., 2014). This alteration may even be enhanced by a high pCO2. Thus, silicate alteration can be essential for a long-term stabilization of volatile CO2 in the form of bicarbonate or may even induce precipitation of carbonate minerals, but these processes are not fully understood yet. The goal of this study is to simulate the alkalinity effect of silicate alteration under diagenetic conditions and high pCO2 by geochemical modeling. We are using the program PHREEQC (Parkhurst and Appelo, 2013) to generate high rock/fluid ratio characteristics for deep subsurface rock reservoirs. Since we are interested in the long-term evolution of diagenetic processes, over millions of years, we do not consider kinetics but calculate the theoretically possible equilibrium conditions. In a first step we are calculating the saturation state of different clay minerals

  14. Phosphatidylinositol anchor of HeLa cell alkaline phosphatase

    International Nuclear Information System (INIS)

    Jemmerson, R.; Low, M.G.


    Alkaline phosphatase from cancer cells, HeLa TCRC-1, was biosynthetically labeled with either 3 H-fatty acids or [ 3 H]ethanolamine as analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography of immunoprecipitated material. Phosphatidylinositol-specific phospholipase C (PI-PLC) released a substantial proportion of the 3 H-fatty acid label from immunoaffinity-purified alkaline phosphatase but had no effect on the radioactivity of [ 3 H]ethanolamine-labeled material. PI-PLC also liberated catalytically active alkaline phosphatase from viable cells, and this could be selectively blocked by monoclonal antibodies to alkaline phosphatase. However, the alkaline phosphatase released from 3 H-fatty acid labeled cells by PI-PLC was not radioactive. By contrast, treatment with bromelain removed both the 3 H-fatty acid and the [ 3 H]ethanolamine label from purified alkaline phosphatase. Subtilisin was also able to remove the [ 3 H]ethanolamine label from the purified alkaline phosphatase. The 3 H radioactivity in alkaline phosphatase purified from [ 3 H]ethanolamine-labeled cells comigrated with authentic [ 3 H]ethanolamine by anion-exchange chromatography after acid hydrolysis. The data suggest that the 3 H-fatty acid and [ 3 H]ethanolamine are covalently attached to the carboxyl-terminal segment since bromelain and subtilisin both release alkaline phosphatase from the membrane by cleavage at that end of the polypeptide chain. The data are consistent with findings for other proteins recently shown to be anchored in the membrane through a glycosylphosphatidylinositol structure and indicate that a similar structure contributes to the membrane anchoring of alkaline phosphatase

  15. The effect of irrigated rice cropping on the alkalinity of two alkaline rice soils in the Sahel

    NARCIS (Netherlands)

    Asten, van P.J.A.; Zelfde, van 't J.A.; Zee, van der S.E.A.T.M.; Hammecker, C.


    Irrigated rice cropping is practiced to reclaim alkaline-sodic soils in many parts of the world. This practice is in apparent contrast with earlier studies in the Sahel, which suggests that irrigated rice cropping may lead to the formation of alkaline-sodic soils. Soil column experiments were done

  16. Quantum electrodynamics of strong fields

    International Nuclear Information System (INIS)

    Greiner, W.


    Quantum Electrodynamics of Strong Fields provides a broad survey of the theoretical and experimental work accomplished, presenting papers by a group of international researchers who have made significant contributions to this developing area. Exploring the quantum theory of strong fields, the volume focuses on the phase transition to a charged vacuum in strong electric fields. The contributors also discuss such related topics as QED at short distances, precision tests of QED, nonperturbative QCD and confinement, pion condensation, and strong gravitational fields In addition, the volume features a historical paper on the roots of quantum field theory in the history of quantum physics by noted researcher Friedrich Hund

  17. Batteries: from alkaline to zinc-air. (United States)

    Dondelinger, Robert M


    There is no perfect disposable battery--one that will sit on the shelf for 20 years, then continually provide unlimited current, at a completely constant voltage until exhausted, without producing heat. There is no perfect rechargeable battery--one with all of the above characteristics and will also withstand an infinite overcharge while providing an equally infinite cycle life. There are only compromises. Every battery selection is a compromise between the ideally required characteristics, the advantages, and the limitations of each battery type. General selection of a battery type to power a medical device is largely outside the purview of the biomed. Initially, these are engineering decisions made at the time of medical equipment design and are intended to be followed in perpetuity. However, since newer cell types evolve and the manufacturer's literature is fixed at the time of printing, some intelligent substitutions may be made as long as the biomed understands the characteristics of both the recommended cell and the replacement cell. For example, when the manufacturer recommends alkaline, it is usually because of the almost constant voltage it produces under the devices' design load. Over time, other battery types may be developed that will meet the intent of the manufacturer, at a lower cost, providing longer operational life, at a lower environmental cost, or with a combination of these advantages. In the Obstetrical Doppler cited at the beginning of this article, the user had put in carbon-zinc cells, and the biomed had unknowingly replaced them with carbonzinc cells. If the alkaline cells recommended by the manufacturer had been used, there would have been the proper output voltage at the battery terminals when the [table: see text] cells were at their half-life. Instead, the device refused to operate since the battery voltage was below presumed design voltage. While battery-type substitutions may be easily and relatively successfully made in disposable

  18. Strong WW Interaction at LHC

    Energy Technology Data Exchange (ETDEWEB)

    Pelaez, Jose R


    We present a brief pedagogical introduction to the Effective Electroweak Chiral Lagrangians, which provide a model independent description of the WW interactions in the strong regime. When it is complemented with some unitarization or a dispersive approach, this formalism allows the study of the general strong scenario expected at the LHC, including resonances.

  19. Strong-back safety latch

    International Nuclear Information System (INIS)

    DeSantis, G.N.


    The calculation decides the integrity of the safety latch that will hold the strong-back to the pump during lifting. The safety latch will be welded to the strong-back and will latch to a 1.5-in. dia cantilever rod welded to the pump baseplate. The static and dynamic analysis shows that the safety latch will hold the strong-back to the pump if the friction clamps fail and the pump become free from the strong-back. Thus, the safety latch will meet the requirements of the Lifting and Rigging Manual for under the hook lifting for static loading; it can withstand shock loads from the strong-back falling 0.25 inch

  20. Strong-back safety latch

    Energy Technology Data Exchange (ETDEWEB)

    DeSantis, G.N.


    The calculation decides the integrity of the safety latch that will hold the strong-back to the pump during lifting. The safety latch will be welded to the strong-back and will latch to a 1.5-in. dia cantilever rod welded to the pump baseplate. The static and dynamic analysis shows that the safety latch will hold the strong-back to the pump if the friction clamps fail and the pump become free from the strong-back. Thus, the safety latch will meet the requirements of the Lifting and Rigging Manual for under the hook lifting for static loading; it can withstand shock loads from the strong-back falling 0.25 inch.

  1. Pt-decorated nanoporous gold for glucose electrooxidation in neutral and alkaline solutions

    Directory of Open Access Journals (Sweden)

    Yan Xiuling


    Full Text Available Abstract Exploiting electrocatalysts with high activity for glucose oxidation is of central importance for practical applications such as glucose fuel cell. Pt-decorated nanoporous gold (NPG-Pt, created by depositing a thin layer of Pt on NPG surface, was proposed as an active electrode for glucose electrooxidation in neutral and alkaline solutions. The structure and surface properties of NPG-Pt were characterized by scanning electron microscopy (SEM, transmission electron microscopy (TEM, X-ray powder diffraction (XRD, and cyclic voltammetry (CV. The electrocatalytic activity toward glucose oxidation in neutral and alkaline solutions was evaluated, which was found to depend strongly on the surface structure of NPG-Pt. A direct glucose fuel cell (DGFC was performed based on the novel membrane electrode materials. With a low precious metal load of less than 0.3 mg cm-2 Au and 60 μg cm-2 Pt in anode and commercial Pt/C in cathode, the performance of DGFC in alkaline is much better than that in neutral condition.

  2. Application of Resin in Pulp Technique for Ion Exchange Separation of Uranium from Alkaline Leachate

    International Nuclear Information System (INIS)

    Sreenivas, T.; Rajan, K.C.; Chakravartty, J.K.


    Conclusions: • Resin-in-pulp technique was applied for purification and enrichment of uranium values from a finely ground uranium ore leach slurry of alkaline nature using strong base anion exchange resin (size 500 - 675μm). • The chemical composition of the solution phase of the alkaline leach slurry (pH 9.5) was consisting of about 40 g/L of total dissolved solutes (TDS) predominantly with Na 2 CO 3 and NaHCO 3 and minor levels of Na 2 SO 4 . The uranium content was only 730 mg/L and d50 of solids was 34μm. • Amongst the various commercially available resins studied PFA 4740 and 4783 having quaternary ammonium ion on polystyrene crosslink with divibyl benzez (DVB) gave best performance. The maximum loading capacity achieved in the RIP studies was about 60-65 g of U 3 O 8 /L of wet settled resin amounting to 98% of loading. This has necessitated 4 stages of counter-current extraction with overall contact time of 100 minutes at a resin to leach slurry volume ratio of about 1:50. Practically the entire uranium values loaded on the resin were eluted using NaCl. • The RIP process was found quite efficient for uranium bearing alkaline leach slurries.

  3. Ultrastable α phase nickel hydroxide as energy storage materials for alkaline secondary batteries (United States)

    Huang, Haili; Guo, Yinjian; Cheng, Yuanhui


    α Phase nickel hydroxide (α-Ni(OH)2) has higher theoretical capacity than that of commercial β phase Ni(OH)2. But the low stability inhibits its wide application in alkaline rechargeable batteries. Here, we propose a totally new idea to stabilize α phase Ni(OH)2 by introducing large organic molecule into the interlayer spacing together with doping multivalent cobalt into the layered Ni(OH)2 host. Ethylene glycol is served as neutral stabilizer in the interlayer spacing. Nickel is substituted by cobalt to increase the electrostatic attraction between layered Ni(OH)2 host and anion ions in the interlayer spacing. Polyethylene glycol (PEG-200) is utilized to design a three-dimensional network structure. This prepared α-Ni(OH)2-20 exhibits specific capacity as high as 334 mAh g-1and good structural stability even after immersing into strong alkaline zincate solution for 20 days. Ni(OH)2 electrode with a specific capacity of 35 mAh cm-2 is fabricated and used as positive electrode in zinc-nickel single flow batteries, which also shows good cycling stability. This result can provide an important guideline for the rational design and preparation of highly active and stable α phase Ni(OH)2 for alkaline secondary battery.

  4. High-Strength / High Alkaline Resistant Fe-Phosphate Glass Fibers as Concrete Reinforcement

    Energy Technology Data Exchange (ETDEWEB)

    Mariano Velez


    Calcium-iron-phosphate glasses were developed whose chemical durabilities in alkaline solutions (pH 13) were comparable or superior to those of commercial alkaline-resistant (AR) silica-based glasses. However, the tensile strength of Ca-Fe-phosphate fibers, after being exposed to alkaline environments, including wet Portland cement pastes, is lower than that of current AR silicate fibers. Another series of Ca-Fe-phosphate glasses were developed with excellent chemical durability in strong acidic solutions (H2SO4, HF), indicating potential applications where silica-based fibers degrade very quickly, including E-glass. The new Ca-Fe-phosphate glasses can be melted and processed 300 to 500°C lower than silica-based glasses. This offers the possibility of manufacturing glass fibers with lower energy costs by 40-60% and the potential to reduce manufacturing waste and lower gas emissions. It was found that Ca-Fe-phosphate melts can be continuously pulled into fibers depending on the slope of the viscosity-temperature curve and with viscosity ~100 poise, using multi-hole Pt/Rh bushings.

  5. Urbanization accelerates long-term salinization and alkalinization of fresh water (United States)

    Kaushal, S.; Duan, S.; Doody, T.; Haq, S.; Smith, R. M.; Newcomer Johnson, T. A.; Delaney Newcomb, K.; Gorman, J. K.; Bowman, N.; Mayer, P. M.; Wood, K. L.; Belt, K.; Stack, W.


    Human dominated land-use increases transport a major ions in streams due to anthropogenic salts and accelerated weathering. We show long-term trends in calcium, magnesium, sodium, alkalinity, and hardness over 50 years in the Baltimore metropolitan region and elsewhere. We also examine how major ion concentrations have increased significantly with impervious surface cover in watersheds across land use. Base cations show strong relationships with acid anions, which illustrates the coupling of major biogeochemical cycles in urban watersheds over time. Longitudinal patterns in major ions can also show increasing trends from headwaters to coastal waters, which suggests coupled biogeochemical cycles over space. We present new results from manipulative experiments and long-term monitoring across different urban regions regarding patterns and processes of salinization and alkalinization. Overall, our work demonstrates that urbanization dramatically increases major ions, ionic strength, and pH over decades from headwaters to coastal waters, which impacts the integrity of aquatic life, infrastructure, drinking water, and coastal ocean alkalinization.

  6. Extraction of uranium from alkaline medium by organic extractants

    International Nuclear Information System (INIS)

    El - nadi, Y.A.M.


    A recent possible route for treatment of small amounts of neutron irradiated uranium from alkaline medium was addressed. This have some advantages related to the isolation of many troublesome fission products which forms insoluble carbonates or hydroxides upon alkaline carbonate dissolution of uranium oxide. In alkaline solution containing sodium carbonate and hydroxide, hexavalent uranium is expected to be dissolved in solution whereby most of the fission products transition elements exemplified by zirconium and niobium as well as trivalent lanthanides and actinides will be precipitated. Therefore, in this medium the solution will contain mainly alkali and alkaline earth metal such as Cs + and Sr 2+ and anionic fission products such as pertechnetates and antimonates, Which can be easily separted from uranium. Therefore, The present thesis is directed to investigate the following; 1 - solubility of uranium oxide in alkaline medium consists of sodium carbonate and sodium hydroxide in presence of oxidizing agent. 2 - Extraction of uranium from the aforementioned alkaline medium by immiscible organic diluent containing different amine extractants. 3 - Extraction behaviour of uranium by the macroporous anion exchanger, amberlite IRA - 410, from alkaline solution

  7. Efficient utilization of licorice root by alkaline extraction. (United States)

    Ohno, Hirokazu; Miyoshi, Shozo; Araho, Daisuke; Kanamoto, Taisei; Terakubo, Shigemi; Nakashima, Hideki; Tsuda, Tadashi; Sunaga, Katsuyoshi; Amano, Shigeru; Ohkoshi, Emika; Sakagami, Hiroshi; Satoh, Kazue; Yamamoto, Masaji


    Compared to studies of water extracts of plants, those utilising alkaline extracts are limited. Both water and alkaline extracts from licorice root were compared regarding their biological activities. Licorice root was successively extracted first with water or alkaline solution (pH 9 or 12), and the alkaline (pH 12.0) extract was further separated into 50% ethanol-soluble and -insoluble fractions. Viable cell number was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. Antibacterial activity against Porphyromonas gingivalis 381 was determined by turbidity assay. Cytochrome P-450 (CYP)3A4 activity was measured by β-hydroxylation of testosterone using human recombinant CYP3A4. Radical intensity of superoxide and hydroxyl radicals was determined by electron spin resonance spectroscopy. Alkaline extraction yielded slightly higher amounts of dried materials compared to water extraction. Alkaline extract showed higher anti-HIV and antibacterial activities, and similar magnitudes of CYP3A4 inhibitory and superoxide and hydroxyl radical-scavenging activities, compared to water extract. When alkaline extract was fractionated by 50% ethanol, anti-HIV activity was recovered from the insoluble fraction representing approximately 3% of the alkaline extract, whereas antibacterial activity was concentrated in the soluble fraction rich in glycyrrhizid acid, flavanones and chalcones. All extracts and sub-fractions led to bimodal hormetic dose-response (maximum hormetic response=238%) on the bacterial growth. The present study demonstrated the superiority of alkaline extraction over water extraction for preparing anti-HIV and antibacterial agents at higher yield from licorice root. Copyright © 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  8. Characterization of alkaline xylanases from Bacillus pumilus

    Directory of Open Access Journals (Sweden)

    Duarte Marta Cristina Teixeira


    Full Text Available Alkaline xylanases produced by four different strains of Bacillus pumilus were characterized. The optimal pH and temperature were pH 9.0 and 60ºC for strain 13a, and pH 8.0 and 55ºC for strains 5(2, 5(14, and 4a. Under these conditions the following activities were found after 10 min in the presence of 1% xylan (birchwood: 328, 131, 90, and 167, respectively, for the four strains. The enzymes were stable at 40ºC, with 40% of the xylanase activity remaining after 2 hours for the enzymes of strain 5(2 and 60% for the other three strains. Stability at 50ºC was improved by addition of glycerol. Taking into account the conditions under which kraft pulps are bleached during the manufacture of paper, xylanases from B. pumilus exhibit favorable potential for application to bleaching in the paper making process.

  9. Response of Desulfovibrio vulgaris to Alkaline Stress

    Energy Technology Data Exchange (ETDEWEB)

    Stolyar, S.; He, Q.; He, Z.; Yang, Z.; Borglin, S.E.; Joyner, D.; Huang, K.; Alm, E.; Hazen, T.C.; Zhou, J.; Wall, J.D.; Arkin, A.P.; Stahl, D.A.


    The response of exponentially growing Desulfovibrio vulgarisHildenborough to pH 10 stress was studied using oligonucleotidemicroarrays and a study set of mutants with genes suggested by microarraydata to be involved in the alkaline stress response deleted. The datashowed that the response of D. vulgaris to increased pH is generallysimilar to that of Escherichia coli but is apparently controlled byunique regulatory circuits since the alternative sigma factors (sigma Sand sigma E) contributing to this stress response in E. coli appear to beabsent in D. vulgaris. Genes previously reported to be up-regulated in E.coli were up-regulated in D. vulgaris; these genes included three ATPasegenes and a tryptophan synthase gene. Transcription of chaperone andprotease genes (encoding ATP-dependent Clp and La proteases and DnaK) wasalso elevated in D. vulgaris. As in E. coli, genes involved in flagellumsynthesis were down-regulated. The transcriptional data also identifiedregulators, distinct from sigma S and sigma E, that are likely part of aD. vulgaris Hildenborough-specific stress response system.Characterization of a study set of mutants with genes implicated inalkaline stress response deleted confirmed that there was protectiveinvolvement of the sodium/proton antiporter NhaC-2, tryptophanase A, andtwo putative regulators/histidine kinases (DVU0331 andDVU2580).

  10. Solubility of pllutonium in alkaline salt solutions

    International Nuclear Information System (INIS)

    Hobbs, D.T.; Edwards, T.B.


    Plutonium solubility data from several studies have been evaluated. For each data set, a predictive model has been developed where appropriate. In addition, a statistical model and corresponding prediction intervals for plutonium solubility as a quadratic function of the hydroxide concentration have been developed. Because of the wide range of solution compositions, the solubility of plutonium can vary by as much as three orders of magnitude for any given hydroxide concentration and still remain within the prediction interval. Any nuclear safety assessments that depend on the maximum amount of plutonium dissolved in alkaline salt solutions should use concentrations at least as great as the upper prediction limits developed in this study. To increase the confidence in the prediction model, it is recommended that additional solubility tests be conducted at low hydroxide concentrations and with all of the other solution components involved. To validate the model for application to actual waste solutions, it is recommended that the plutonium solubilities in actual waste solutions be determined and compared to the values predicted by the quadratic model

  11. Alkaline Phosphatase, an Unconventional Immune Protein

    Directory of Open Access Journals (Sweden)

    Bethany A. Rader


    Full Text Available Recent years have seen an increase in the number of studies focusing on alkaline phosphatases (APs, revealing an expanding complexity of function of these enzymes. Of the four human AP (hAP proteins, most is known about tissue non-specific AP (TNAP and intestinal AP (IAP. This review highlights current understanding of TNAP and IAP in relation to human health and disease. TNAP plays a role in multiple processes, including bone mineralization, vitamin B6 metabolism, and neurogenesis, is the genetic cause of hypophosphatasia, influences inflammation through regulation of purinergic signaling, and has been implicated in Alzheimer’s disease. IAP regulates fatty acid absorption and has been implicated in the regulation of diet-induced obesity and metabolic syndrome. IAP and TNAP can dephosphorylate bacterial-derived lipopolysaccharide, and IAP has been identified as a potential regulator of the composition of the intestinal microbiome, an evolutionarily conserved function. Endogenous and recombinant bovine APs and recombinant hAPs are currently being explored for their potential as pharmacological agents to treat AP-associated diseases and mitigate multiple sources of inflammation. Continued research on these versatile proteins will undoubtedly provide insight into human pathophysiology, biochemistry, and the human holobiont.

  12. Alkaline Materials and Regenerative Endodontics: A Review

    Directory of Open Access Journals (Sweden)

    Bill Kahler


    Full Text Available Periapical health is the primary goal of endodontic treatment in mature and immature teeth. In addition, the goals of treatment of immature teeth with arrested root development include root growth to length and maturation of the apex, as well as thickening of the canal wall. These goals are valid for immature teeth that have been subjected to trauma and dental caries or that are the result of developmental anomalies that expose the tooth to the risk of pulp necrosis and consequently result in the cessation of root maturation. Regenerative endodontic procedures (REPs have been described as a “paradigm shift” in the treatment of immature teeth with pulp necrosis and underdeveloped roots, as there is the potential for further root maturation and return of vitality. Treatment with REPs is advocated as the treatment of choice for immature teeth with pulp necrosis. REP protocols involve the use of alkaline biomaterials, primarily sodium hypochlorite, calcium hydroxide, mineral trioxide aggregates and Biodentine, and are the essential components of a successful treatment regimen.

  13. Pseudomonas syringae evades host Immunity by degrading flagellin monomers with alkaline protease AprA


    Pel, M.J.C.; Van Dijken, A.J.H.; Bardoel, B.W.; Seidl, M.F; Van der Ent, S.; Van Strijp, J.A.G.


    Bacterial flagellin molecules are strong inducers of innate immune responses in both mammals and plants. The opportunistic pathogen Pseudomonas aeruginosa secretes an alkaline protease called AprA that degrades flagellin monomers. Here, we show that AprA is widespread among a wide variety of bacterial species. In addition, we investigated the role of AprA in virulence of the bacterial plant athogen P. syringae pv. tomato DC3000. The AprA-deficient DC3000 ΔaprA knockout mutant was significantl...

  14. Titanium: light, strong, and white (United States)

    Woodruff, Laurel; Bedinger, George


    Titanium (Ti) is a strong silver-gray metal that is highly resistant to corrosion and is chemically inert. It is as strong as steel but 45 percent lighter, and it is twice as strong as aluminum but only 60 percent heavier. Titanium dioxide (TiO2) has a very high refractive index, which means that it has high light-scattering ability. As a result, TiO2 imparts whiteness, opacity, and brightness to many products. ...Because of the unique physical properties of titanium metal and the whiteness provided by TiO2, titanium is now used widely in modern industrial societies.

  15. The Estimation Formation Alkaline In The Proses Desalination MSF

    International Nuclear Information System (INIS)

    Latiffah, Siti Nurul


    Already to go on estimation phenomena formation alkaline scale of a seawater. In desalination system seawater on MSF to go on scale by a thermal decomposition HCO sub.3- ion and hydrolysis carbonate ion with water on the temperature operation. The varieties alkaline scale in attached on tube surface, while reduced efficiency heat transfer and to raise corrosion attack to structure material is caused all this high cost. Estimation to take please which a sum step by step decomposition ion bicarbonate from then information scale which carbonate and hydroxyl ion. The various scale maximal is alkaline form is a calcium carbonate = 116,5 gram per meter cubic the various sedimentation is alkaline and magnesium hydroxide = 67,57 gram per meter cubic

  16. Microbial alkaline pectinases and their industrial applications: a review. (United States)

    Hoondal, G S; Tiwari, R P; Tewari, R; Dahiya, N; Beg, Q K


    The biotechnological potential of pectinolytic enzymes from microorganisms has drawn a great deal of attention from various researchers worldwide as likely biological catalysts in a variety of industrial processes. Alkaline pectinases are among the most important industrial enzymes and are of great significance in the current biotechnological arena with wide-ranging applications in textile processing, degumming of plant bast fibers, treatment of pectic wastewaters, paper making, and coffee and tea fermentations. The present review features the potential applications and uses of microbial alkaline pectinases, the nature of pectin, and the vast range of pectinolytic enzymes that function to mineralize pectic substances present in the environment. It also emphasizes the environmentally friendly applications of microbial alkaline pectinases thereby revealing their underestimated potential. The review intends to explore the potential of these enzymes and to encourage new alkaline pectinase-based industrial technology.

  17. Microbial alkaline proteases: Optimization of production parameters and their properties

    Directory of Open Access Journals (Sweden)

    Kanupriya Miglani Sharma


    Full Text Available Proteases are hydrolytic enzymes capable of degrading proteins into small peptides and amino acids. They account for nearly 60% of the total industrial enzyme market. Proteases are extensively exploited commercially, in food, pharmaceutical, leather and detergent industry. Given their potential use, there has been renewed interest in the discovery of proteases with novel properties and a constant thrust to optimize the enzyme production. This review summarizes a fraction of the enormous reports available on various aspects of alkaline proteases. Diverse sources for isolation of alkaline protease producing microorganisms are reported. The various nutritional and environmental parameters affecting the production of alkaline proteases in submerged and solid state fermentation are described. The enzymatic and physicochemical properties of alkaline proteases from several microorganisms are discussed which can help to identify enzymes with high activity and stability over extreme pH and temperature, so that they can be developed for industrial applications.

  18. Palladium-based nanocatalysts for alcohol electrooxidation in alkaline media

    CSIR Research Space (South Africa)

    Modibedi, RM


    Full Text Available Direct alcohol alkaline fuel cells (DAAFCs) are potential power sources for a variety of portable applications as they provide unique advantages over hydrogen-based fuel cell devices. Alcohols (such as methanol, ethanol, ethylene glycol...

  19. Effects of alkaline treatment for fibroblastic adhesion on titanium

    Directory of Open Access Journals (Sweden)

    Miryam Cuellar-Flores


    Conclusion: The treatment of Ti plates with NaOH enhances cell adhesion and the proliferation of HPLF cells. Clinically, the alkaline treatment of Ti-based implants could be an option to improve and accelerate osseointegration.

  20. Kinetics of the Fading of Phenolphthalein in Alkaline Solution. (United States)

    Nicholson, Lois


    Described is an experiment which illustrates pseudo-first-order kinetics in the fading of a common indicator in an alkaline solution. Included are background information, details of materials used, laboratory procedures, and sample results. (CW)

  1. Net alkalinity and net acidity 1: Theoretical considerations

    International Nuclear Information System (INIS)

    Kirby, Carl S.; Cravotta, Charles A.


    Net acidity and net alkalinity are widely used, poorly defined, and commonly misunderstood parameters for the characterization of mine drainage. The authors explain theoretical expressions of 3 types of alkalinity (caustic, phenolphthalein, and total) and acidity (mineral, CO 2 , and total). Except for rarely-invoked negative alkalinity, theoretically defined total alkalinity is closely analogous to measured alkalinity and presents few practical interpretation problems. Theoretically defined 'CO 2 -acidity' is closely related to most standard titration methods with an endpoint pH of 8.3 used for determining acidity in mine drainage, but it is unfortunately named because CO 2 is intentionally driven off during titration of mine-drainage samples. Using the proton condition/mass-action approach and employing graphs to illustrate speciation with changes in pH, the authors explore the concept of principal components and how to assign acidity contributions to aqueous species commonly present in mine drainage. Acidity is defined in mine drainage based on aqueous speciation at the sample pH and on the capacity of these species to undergo hydrolysis to pH 8.3. Application of this definition shows that the computed acidity in mgL -1 as CaCO 3 (based on pH and analytical concentrations of dissolved Fe II , Fe III , Mn, and Al in mgL -1 ):acidity calculated =50{1000(10 -pH )+[2(Fe II )+3(Fe III )]/56+2(Mn) /55+3(Al)/27}underestimates contributions from HSO 4 - and H + , but overestimates the acidity due to Fe 3+ and Al 3+ . However, these errors tend to approximately cancel each other. It is demonstrated that 'net alkalinity' is a valid mathematical construction based on theoretical definitions of alkalinity and acidity. Further, it is shown that, for most mine-drainage solutions, a useful net alkalinity value can be derived from: (1) alkalinity and acidity values based on aqueous speciation (2) measured alkalinity minus calculated acidity, or (3) taking the negative of the

  2. Fluorescence quenching based alkaline phosphatase activity detection. (United States)

    Mei, Yaqi; Hu, Qiong; Zhou, Baojing; Zhang, Yonghui; He, Minhui; Xu, Ting; Li, Feng; Kong, Jinming


    Simple and fast detection of alkaline phosphatase (ALP) activity is of great importance for diagnostic and analytical applications. In this work, we report a turn-off approach for the real-time detection of ALP activity on the basis of the charge transfer induced fluorescence quenching of the Cu(BCDS) 2 2- (BCDS = bathocuproine disulfonate) probe. Initially, ALP can enzymatically hydrolyze the substrate ascorbic acid 2-phosphate to release ascorbic acid (AA). Subsequently, the AA-mediated reduction of the Cu(BCDS) 2 2- probe, which displays an intense photoluminescence band at the wavelength of 402nm, leads to the static quenching of fluorescence of the probe as a result of charge transfer. The underlying mechanism of the fluorescence quenching was demonstrated by quantum mechanical calculations. The Cu(BCDS) 2 2- probe features a large Stokes shift (86nm) and is highly immune to photo bleaching. In addition, this approach is free of elaborately designed fluorescent probes and allows the detection of ALP activity in a real-time manner. Under optimal conditions, it provides a fast and sensitive detection of ALP activity within the dynamic range of 0-220mUmL -1 , with a detection limit down to 0.27mUmL -1 . Results demonstrate that it is highly selective, and applicable to the screening of ALP inhibitors in drug discovery. More importantly, it shows a good analytical performance for the direct detection of the endogenous ALP levels of undiluted human serum and even whole blood samples. Therefore, the proposed charge transfer based approach has great potential in diagnostic and analytical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Photovoltaic hydrogen production with commercial alkaline electrolysers

    Energy Technology Data Exchange (ETDEWEB)

    Ursua, A.; Lopez, J.; Gubia, E.; Marroyo, L.; Sanchis, P. [Public Univ. of Navarra, Pamplona (Spain). Dept. of Electric and Electronic Engineering


    Renewable energy sources and Electrolysis generate the so-called green Hydrogen, a zero-emission and potentially fossil fuel independent energy source. However, the inherent variability of the renewable energy sources implies a mode of operation for which most current electrolysers have not been designed. This paper analyses the operation of a water electrolyser fed with photovoltaic (PV) generator electric profile. The system, Integrated by a 1 Nm{sup 3}/h Hydrogenics alkaline electrolyser and a 5100 W PV generator with 60 BP585 modules, is installed at the Public University of Navarra (Spain). The PV generator profile fed to the electrolyser is emulated by a custom-made apparatus designed and built by the authors of this paper. The profile is designed according to real irradiance data measured by a calibration cell. The irradiance data are converted to the electric power profile that the PV generator would have delivered in case of having been connected to the electrolyser by means of a DC/DC converter with maximum power point tracking (MPPT). Finally, from previously measured power-current electrolyser characteristic curves, the current profile to be delivered to the electrolyser is obtained and programmed to the electronic device. The electrolyser was tested for two types of days. During the first day, the irradiance was very stable, whereas during the second day, the irradiance was very variable. The experimental results show an average power consumption rate and an efficiency of 4908 Wh/Nm{sup 3} and 72.1%, on the first day, and 4842 Wh/Nm{sup 3} and 73.3% on the second day. The electrolyser performance was particularly good in spite of the high variability of the electric supply of the second day. (orig.)

  4. Chlorine solubility in evolved alkaline magmas

    Directory of Open Access Journals (Sweden)

    M. R. Carroll


    Full Text Available Experimental studies of Cl solubility in trachytic to phonolitic melts provide insights into the capacity of alkaline magmas to transport Cl from depth to the earth?s surface and atmosphere, and information on Cl solubility variations with pressure, temperature and melt or fluid composition is crucial for understanding the reasons for variations in Cl emissions at active volcanoes. This paper provides a brief review of Cl solubility experiments conducted on a range of trachytic to phonolitic melt compositions. Depending on the experimental conditions the melts studied were in equilibrium with either a Cl-bearing aqueous fluid or a subcritical assemblage of low- Cl aqueous fluid + Cl-rich brine. The nature of the fluid phase(s was identified by examination of fluid inclusions present in run product glasses and the fluid bulk composition was calculated by mass balance. Chlorine concentrations in the glass increase with increasing Cl molality in the fluid phase until a plateau in Cl concentration is reached when melt coexists with aqueous fluid + brine. With fluids of similar Cl molality, higher Cl concentrations are observed in peralkaline phonolitic melts compared with peraluminous phonolitic melts; overall the Cl concentrations observed in phonolitic and trachytic melts are approximately twice those found in calcalkaline rhyolitic melts under similar conditions. The observed negative pressure dependence of Cl solubility implies that Cl contents of melts may actually increase during magma decompression if the magma coexists with aqueous fluid and Cl-rich brine (assuming melt-vapor equilibrium is maintained. The high Cl contents (approaching 1 wt% Cl observed in some melts/glasses from the Vesuvius and Campi Flegrei areas suggest saturation with a Cl-rich brine prior to eruption.

  5. Alkaline Peroxide Delignification of Corn Stover

    Energy Technology Data Exchange (ETDEWEB)

    Mittal, Ashutosh [Biosciences; Katahira, Rui [National; Donohoe, Bryon S. [Biosciences; Black, Brenna A. [National; Pattathil, Sivakumar [Complex; Stringer, Jack M. [National; Beckham, Gregg T. [National


    Selective biomass fractionation into carbohydrates and lignin is a key challenge in the conversion of lignocellulosic biomass to fuels and chemicals. In the present study, alkaline hydrogen peroxide (AHP) pretreatment was investigated to fractionate lignin from polysaccharides in corn stover (CS), with a particular emphasis on the fate of the lignin for subsequent valorization. The influence of peroxide loading on delignification during AHP pretreatment was examined over the range of 30-500 mg H2O2/g dry CS at 50 degrees C for 3 h. Mass balances were conducted on the solid and liquid fractions generated after pretreatment for each of the three primary components, lignin, hemicellulose, and cellulose. AHP pretreatment at 250 mg H2O2/g dry CS resulted in the pretreated solids with more than 80% delignification consequently enriching the carbohydrate fraction to >90%. Two-dimensional nuclear magnetic resonance (2D-NMR) spectroscopy of the AHP pretreated residue shows that, under high peroxide loadings (>250 mg H2O2/g dry CS), most of the side chain structures were oxidized and the aryl-ether bonds in lignin were partially cleaved, resulting in significant delignification of the pretreated residues. Gel permeation chromatography (GPC) analysis shows that AHP pretreatment effectively depolymerizes CS lignin into low molecular weight (LMW) lignin fragments in the aqueous fraction. Imaging of AHP pretreated residues shows a more granular texture and a clear lamellar pattern in secondary walls, indicative of layers of varying lignin removal or relocalization. Enzymatic hydrolysis of this pretreated residue at 20 mg/g of glucan resulted in 90% and 80% yields of glucose and xylose, respectively, after 120 h. Overall, AHP pretreatment is able to selectively remove more than 80% of the lignin from biomass in a form that has potential for downstream valorization processes and enriches the solid pulp into a highly digestible material.

  6. Economic Analysis of Improved Alkaline Water Electrolysis

    International Nuclear Information System (INIS)

    Kuckshinrichs, Wilhelm; Ketelaer, Thomas; Koj, Jan Christian


    Alkaline water electrolysis (AWE) is a mature hydrogen production technology and there exists a range of economic assessments for available technologies. For advanced AWEs, which may be based on novel polymer-based membrane concepts, it is of prime importance that development comes along with new configurations and technical and economic key process parameters for AWE that might be of interest for further economic assessments. This paper presents an advanced AWE technology referring to three different sites in Europe (Germany, Austria, and Spain). The focus is on financial metrics, the projection of key performance parameters of advanced AWEs, and further financial and tax parameters. For financial analysis from an investor’s (business) perspective, a comprehensive assessment of a technology not only comprises cost analysis but also further financial analysis quantifying attractiveness and supply/market flexibility. Therefore, based on cash flow (CF) analysis, a comprehensible set of metrics may comprise levelised cost of energy or, respectively, levelized cost of hydrogen (LCH) for cost assessment, net present value (NPV) for attractiveness analysis, and variable cost (VC) for analysis of market flexibility. The German AWE site turns out to perform best in all three financial metrics (LCH, NPV, and VC). Though there are slight differences in investment cost and operation and maintenance cost projections for the three sites, the major cost impact is due to the electricity cost. Although investment cost is slightly lower and labor cost is significantly lower in Spain, the difference can not outweigh the higher electricity cost compared to Germany. Given the assumption that the electrolysis operators are customers directly and actively participating in power markets, and based on the regulatory framework in the three countries, in this special case electricity cost in Germany is lowest. However, as electricity cost is profoundly influenced by political decisions as

  7. Emplacement of Amba Dongar Carbonatite-alkaline Complex at ...

    Indian Academy of Sciences (India)

    40Ar-39Ar analyses of three fresh alkaline rock samples and a phlogopite separate from a carbonatite from Amba Dongar carbonatite-alkaline complex of the Deccan Flood Basalt Province, India, yield indistinguishable precise plateau ages of 64.8 ± 0.6, 64.7 ± 0.5, 65.5 ± 0.8 and 65.3 ± 0.6 Ma, giving a mean plateau age ...

  8. Processes determining the marine alkalinity and carbonate saturation distributions


    B. R. Carter; J. R. Toggweiler; R. M. Key; J. L. Sarmiento


    We introduce a composite tracer, Alk*, that has a global distribution primarily determined by CaCO3 precipitation and dissolution. Alk* also highlights riverine alkalinity plumes that are due to dissolved calcium carbonate from land. We estimate the Arctic receives approximately twice the riverine alkalinity per unit area as the Atlantic, and 8 times that of the other oceans. Riverine inputs broadly elevate Alk* in the Arctic surface and particularly near ri...

  9. Sulfur-containing compounds heated under alkaline condition: antibrowning, antioxidative activities, and their effect on quality of shrimp during iced storage. (United States)

    Phonpala, Yoottana; Benjakul, Soottawat; Visessanguan, Wonnop; Eun, Jong-Bang


    Sulfur-containing compounds heated under alkaline condition (pH 10) were determined for inhibitory activity toward polyphenol oxidase (PPO) from Pacific white shrimp (Litopenaeus vannamei) and for antioxidative activity. Cysteine and glutathione (GSH) (20 mM) heated at 100 degrees C at pH 10 strongly inhibited PPO activity. Heated alkaline cysteine showed the greater 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picryl hydrazyl (DPPH) radical scavenging activity, copper-chelating activity and reducing power than cysteine and glucose-cysteine Maillard reaction products (P alkaline cysteine at different concentrations (0, 20, and 100 mM) on the quality changes of Pacific white shrimp during iced storage was investigated. Shrimp treated with 100 mM heated alkaline cysteine had the lowest melanosis score, thiobarbituric acid-reactive substances (TBARS) value and total viable count (TVC), compared with those without treatment and treated with 20 mM heated alkaline cysteine, throughout the storage of 12 d (P alkaline cysteine can be used as a novel additive to retard melanosis and extend the quality of postmortem shrimp.

  10. Acid transformation of bauxite residue: Conversion of its alkaline characteristics. (United States)

    Kong, Xiangfeng; Li, Meng; Xue, Shengguo; Hartley, William; Chen, Chengrong; Wu, Chuan; Li, Xiaofei; Li, Yiwei


    Bauxite residue (BR) is a highly alkaline solid hazardous waste produced from bauxite processing for alumina production. Alkaline transformation appears to reduce the environmental risk of bauxite residue disposal areas (BRDAs) whilst potentially providing opportunities for the sustainable reuse and on-going management of BR. Mineral acids, a novel citric acid and a hybrid combination of acid-gypsum treatments were investigated for their potential to reduce residue pH and total alkalinity and transform the alkaline mineral phase. XRD results revealed that with the exception of andradite, the primary alkaline solid phases of cancrinite, grossular and calcite were transformed into discriminative products based on the transformation used. Supernatants separated from BR and transformed bauxite residue (TBR) displayed distinct changes in soluble Na, Ca and Al, and a reduction in pH and total alkalinity. SEM images suggest that mineral acid transformations promote macro-aggregate formation, and the positive promotion of citric acid, confirming the removal or reduction in soluble and exchangeable Na. NEXAFS analysis of Na K-edge revealed that the chemical speciation of Na in TBRs was consistent with BR. Three acid treatments and gypsum combination had no effect on Na speciation, which affects the distribution of Na revealed by sodium STXM imaging. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Overexpression of Human Bone Alkaline Phosphatase in Pichia Pastoris (United States)

    Karr, Laurel; Malone, Christine, C.; Rose, M. Franklin (Technical Monitor)


    The Pichiapastoris expression system was utilized to produce functionally active human bone alkaline phosphatase in gram quantities. Bone alkaline phosphatase is a key enzyme in bone formation and biomineralization, yet important questions about its structural chemistry and interactions with other cellular enzymes in mineralizing tissues remain unanswered. A soluble form of human bone alkaline phosphatase was constructed by deletion of the 25 amino acid hydrophobic C-terminal region of the encoding cDNA and inserted into the X-33 Pichiapastoris strain. An overexpression system was developed in shake flasks and converted to large-scale fermentation. Alkaline phosphatase was secreted into the medium to a level of 32mgAL when cultured in shake flasks. Enzyme activity was 12U/mg measured by a spectrophotometric assay. Fermentation yielded 880mgAL with enzymatic activity of 968U/mg. Gel electrophoresis analysis indicates that greater than 50% of the total protein in the fermentation is alkaline phosphatase. A purification scheme has been developed using ammonium sulfate precipitation followed by hydrophobic interaction chromatography. We are currently screening crystallization conditions of the purified recombinant protein for subsequent X-ray diffraction analyses. Structural data should provide additional information on the role of alkaline phosphatase in normal bone mineralization and in certain bone mineralization anomalies.

  12. The SNAP Strong Lens Survey

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, P.


    Basic considerations of lens detection and identification indicate that a wide field survey of the types planned for weak lensing and Type Ia SNe with SNAP are close to optimal for the optical detection of strong lenses. Such a ''piggy-back'' survey might be expected even pessimistically to provide a catalogue of a few thousand new strong lenses, with the numbers dominated by systems of faint blue galaxies lensed by foreground ellipticals. After sketching out our strategy for detecting and measuring these galaxy lenses using the SNAP images, we discuss some of the scientific applications of such a large sample of gravitational lenses: in particular we comment on the partition of information between lens structure, the source population properties and cosmology. Understanding this partitioning is key to assessing strong lens cosmography's value as a cosmological probe.

  13. Strong coupling phase in QED

    International Nuclear Information System (INIS)

    Aoki, Ken-ichi


    Existence of a strong coupling phase in QED has been suggested in solutions of the Schwinger-Dyson equation and in Monte Carlo simulation of lattice QED. In this article we recapitulate the previous arguments, and formulate the problem in the modern framework of the renormalization theory, Wilsonian renormalization. This scheme of renormalization gives the best understanding of the basic structure of a field theory especially when it has a multi-phase structure. We resolve some misleading arguments in the previous literature. Then we set up a strategy to attack the strong phase, if any. We describe a trial; a coupled Schwinger-Dyson equation. Possible picture of the strong coupling phase QED is presented. (author)

  14. Involvement of membrane potential in alkaline band formation by internodal cells of Chara corallina. (United States)

    Shimmen, Teruo; Wakabayashi, Akiko


    Internodal cells of Chara corallina form alkaline bands on their surface upon illumination via photosynthesis. In the present study, the effect of KCl on alkaline band formation was analyzed. When the extracellular KCl concentration was increased, alkaline band formation was extensively inhibited. Electrophysiological analysis unequivocally showed the need for inner negative membrane potential for alkaline band formation.

  15. 40 CFR 420.110 - Applicability; description of the alkaline cleaning subcategory. (United States)


    ... alkaline cleaning subcategory. 420.110 Section 420.110 Protection of Environment ENVIRONMENTAL PROTECTION... Alkaline Cleaning Subcategory § 420.110 Applicability; description of the alkaline cleaning subcategory... alkaline cleaning baths to remove mineral and animal fats or oils from the steel, and those rinsing...

  16. 21 CFR 862.1050 - Alkaline phosphatase or isoenzymes test system. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Alkaline phosphatase or isoenzymes test system... Test Systems § 862.1050 Alkaline phosphatase or isoenzymes test system. (a) Identification. An alkaline phosphatase or isoenzymes test system is a device intended to measure alkaline phosphatase or its isoenzymes...

  17. A critical re-evaluation of the prediction of alkalinity and base cation chemistry from BGS sediment composition data. (United States)

    Begum, S; McClean, C J; Cresser, M S; Adnan, M; Breward, N


    The model of Begum et al. (2010) that predicts alkalinity and Ca and Mg concentrations in river water from available sediment composition data has been critically re-evaluated using an independent validation data set. The results support the hypothesis that readily available stream water sediment elemental composition data are useful for prediction of mean and minimum concentrations of alkalinity and Ca and Mg in river water throughout the River Derwent catchment in North Yorkshire without requiring land-use data inputs as stream water sediment composition reflects all aspects of the riparian zone soil system, including land-use. However, it was shown for alkalinity prediction that rainfall exerts a significant dilution effect and should be incorporated into the model in addition to flow path-weighted sediments Ca% and Mg%. The results also strongly suggest that in catchments with substantial rough moorland land-use neutralization of organic acids consumes alkalinity and this fact should be considered in any future development of the model. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. A single pH fluorescent probe for biosensing and imaging of extreme acidity and extreme alkalinity. (United States)

    Chao, Jian-Bin; Wang, Hui-Juan; Zhang, Yong-Bin; Li, Zhi-Qing; Liu, Yu-Hong; Huo, Fang-Jun; Yin, Cai-Xia; Shi, Ya-Wei; Wang, Juan-Juan


    A simple tailor-made pH fluorescent probe 2-benzothiazole (N-ethylcarbazole-3-yl) hydrazone (Probe) is facilely synthesized by the condensation reaction of 2-hydrazinobenzothiazole with N-ethylcarbazole-3-formaldehyde, which is a useful fluorescent probe for monitoring extremely acidic and alkaline pH, quantitatively. The pH titrations indicate that Probe displays a remarkable emission enhancement with a pK a of 2.73 and responds linearly to minor pH fluctuations within the extremely acidic range of 2.21-3.30. Interestingly, Probe also exhibits strong pH-dependent characteristics with pK a 11.28 and linear response to extreme-alkalinity range of 10.41-12.43. In addition, Probe shows a large Stokes shift of 84 nm under extremely acidic and alkaline conditions, high selectivity, excellent sensitivity, good water-solubility and fine stability, all of which are favorable for intracellular pH imaging. The probe is further successfully applied to image extremely acidic and alkaline pH values fluctuations in E. coli cells. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Fundamental Mechanistic Understanding of Electrocatalysis of Oxygen Reduction on Pt and Non-Pt Surfaces: Acid versus Alkaline Media

    Directory of Open Access Journals (Sweden)

    Nagappan Ramaswamy


    Full Text Available Complex electrochemical reactions such as Oxygen Reduction Reaction (ORR involving multi-electron transfer is an electrocatalytic inner-sphere electron transfer process that exhibit strong dependence on the nature of the electrode surface. This criterion (along with required stability in acidic electrolytes has largely limited ORR catalysts to the platinum-based surfaces. New evidence in alkaline media, discussed here, throws light on the involvement of surface-independent outer-sphere electron transfer component in the overall electrocatalytic process. This surface non-specificity gives rise to the possibility of using a wide-range of non-noble metal surfaces as electrode materials for ORR in alkaline media. However, this outer-sphere process predominantly leads only to peroxide intermediate as the final product. The importance of promoting the electrocatalytic inner-sphere electron transfer by facilitation of direct adsorption of molecular oxygen on the active site is emphasized by using pyrolyzed metal porphyrins as electrocatalysts. A comparison of ORR reaction mechanisms between acidic and alkaline conditions is elucidated here. The primary advantage of performing ORR in alkaline media is found to be the enhanced activation of the peroxide intermediate on the active site that enables the complete four-electron transfer. ORR reaction schemes involving both outer- and inner-sphere electron transfer mechanisms are proposed.

  20. Effect of alkaline addition on anaerobic sludge digestion with combined pretreatment of alkaline and high pressure homogenization. (United States)

    Fang, Wei; Zhang, Panyue; Zhang, Guangming; Jin, Shuguang; Li, Dongyi; Zhang, Meixia; Xu, Xiangzhe


    To improve anaerobic digestion efficiency, combination pretreatment of alkaline and high pressure homogenization was applied to pretreat sewage sludge. Effect of alkaline dosage on anaerobic sludge digestion was investigated in detail. SCOD of sludge supernatant significantly increased with the alkaline dosage increase after the combined pretreatment because of sludge disintegration. Organics were significantly degraded after the anaerobic digestion, and the maximal SCOD, TCOD and VS removal was 73.5%, 61.3% and 43.5%, respectively. Cumulative biogas production, methane content in biogas and biogas production rate obviously increased with the alkaline dosage increase. Considering both the biogas production and alkaline dosage, the optimal alkaline dosage was selected as 0.04 mol/L. Relationships between biogas production and sludge disintegration showed that the accumulative biogas was mainly enhanced by the sludge disintegration. The methane yield linearly increased with the DDCOD increase as Methane yield (ml/gVS)=4.66 DDCOD-9.69. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Acidic minespoil reclamation with alkaline biosolids

    International Nuclear Information System (INIS)

    Drill, C.; Lindsay, B.J.; Logan, T.L.


    The effectiveness of an alkaline stabilized biosolids product, N-Viro Soil (NVS), was studied at a wild animal preserve in Cumberland, OH. The preserve occupies land that was strip mined for high-sulfur coal. While most of the land has been conventionally reclaimed, several highly acidic hot spots remain. Two of these hot spots were studied through concurrent field, greenhouse, and laboratory projects. In April 1995, NVS was applied at rates ranging from 0--960 mt/ha (wet wt.) to plots at the two sites. The plots were seeded using a standard reclamation mix and soil samples were analyzed for chemical characteristics before and after application and also in 1996 and 1997. Soil pH increased from 3.5 to about 11 in the amended plots and soil EC values increased from 21.0 mmho/cm to a maximum of 6.0 mmho/cm in the amended plots immediately after application. Soil Cu and Zn concentrations also increased in the NVS amended plots, but this did not affect plant germination or growth. By the summer of 1996, soil pH values had decreased to 7.3--8.7 and EC values decreased to 0.34--1.36 mmho/cm to the amended plots. Soil samples were collected in September 1995 for physical analyses. N-Viro Soil improved the moisture retention and water conductivity properties of the spoil. The plots were monitored for growth during the summer of 1995 and plant biomass and soil samples were taken in 1996 and 1997 for trace element and nutrient analysis. NVS did not significantly increase trace element concentrations in the biomass. The addition of NVS to acid mine spoil improves the chemical and physical properties of the spoil material thus aiding vegetative establishment and growth. NVS improves the chemical nature of the spoil by increasing pH and providing micro and macronutrients and improves the physical properties of the spoil with the addition of organic matter

  2. Alkaline phosphatase in boar sperm function. (United States)

    Bucci, D; Isani, G; Giaretta, E; Spinaci, M; Tamanini, C; Ferlizza, E; Galeati, G


    Alkaline phosphatase (AP) catalyses the detachment of phosphate residues from different substrates. Its activity has been demonstrated in seminal plasma and spermatozoa from porcine and other mammalian species; anyway, the role of AP in male reproduction has not been clarified yet and the aim of this study was to determine AP function in boar sperm capacitation and in vitro fertilization (IVF). AP activity was assayed in seminal plasma and in uncapacitated and in vitro capacitated (IVC) spermatozoa; in addition, capacitation was studied in presence of different doses of AP (1.2 and 2.5 IU/mL). The effect of different doses of AP (1.2 and 2.5 IU/mL) on several sperm parameters after IVC (viability, acrosome integrity with FITC-PSA, capacitation status with CTC staining, tyrosine phosphorylation) and on fertilizing ability during IVF were also evaluated. High AP activity was detected in seminal plasma, in particular in sperm-rich fraction; a lower activity was detected in uncapacitated spermatozoa while a significant decrease was evidenced after IVC. Viability was not changed by AP supplementation of the capacitating medium, whereas acrosome integrity and capacitation status were significantly affected by 1.2 and 2.5 doses, with a dose-dependent decrease in acrosome-reacted cells as well as in CTC B pattern displaying cells. As for sperm head protein phosphorylation, a decrease in relative fluorescence was detected in AP 2.5 group, if compared with capacitated one. After IVF, a dose-dependent decrease in penetrated oocytes was recorded, with an increase in monospermic zygote rate. In conclusion, we demonstrated that AP activity decreases under capacitating condition and that addition of AP to spermatozoa during capacitation results in a depression of the capacitating process and IVF. We can infer that AP plays a role in keeping spermatozoa quiescent until they are ejaculated and in modulating the acquisition of the fertilizing ability. © 2013 American Society of

  3. Room temperature strong light-matter coupling in 3D THz meta-atoms (Conference Presentation) (United States)

    Paulillo, Bruno; Manceau, Jean-Michel; Li, Lianhe; Linfield, Edmund; Colombelli, Raffaele


    We demonstrate strong light-matter coupling at room temperature in the terahertz (THz) spectral region using 3D meta-atoms with extremely sub-wavelength volumes. Using an air-bridge fabrication scheme, we have implemented sub-wavelength 3D THz micro-resonators that rely on suspended loop antennas connected to semiconductor-filled patch cavities. We have experimentally shown that they possess the functionalities of lumped LC resonators: their frequency response can be adjusted by independently tuning the inductance associated the antenna element or the capacitance provided by the metal-semiconductor-metal cavity. Moreover, the radiation coupling and efficiency can be engineered acting on the design of the loop antenna, similarly to conventional RF antennas. Here we take advantage of this rich playground in the context of cavity electrodynamics/intersubband polaritonics. In the strong light-matter coupling regime, a cavity and a two-level system exchange energy coherently at a characteristic rate called the vacuum Rabi frequency ΩR which is dominant with respect to all other loss mechanisms involved. The signature, in the frequency domain, is the appearance of a splitting between the bare cavity and material system resonances: the new states are called upper and a lower polariton branches. So far, most experimental demonstrations of strong light-matter interaction between an intersubband transition and a deeply sub-wavelength mode in the THz or mid-infrared ranges rely on wavelength-scale or larger resonators such as photonic crystals, diffractive gratings, dielectric micro-cavities or patch cavities. Lately, planar metamaterials have been used to enhance the light-matter interaction and strongly reduce the interaction volume by engineering the electric and magnetic resonances of the individual subwavelength constituents. In this contribution we provide evidence of strong coupling between a THz intersubband transition and an extremely sub-wavelength mode (≈λ/10

  4. Strong Decomposition of Random Variables

    DEFF Research Database (Denmark)

    Hoffmann-Jørgensen, Jørgen; Kagan, Abram M.; Pitt, Loren D.


    A random variable X is stongly decomposable if X=Y+Z where Y=Φ(X) and Z=X-Φ(X) are independent non-degenerated random variables (called the components). It is shown that at least one of the components is singular, and we derive a necessary and sufficient condition for strong decomposability...

  5. Strong interaction at finite temperature

    Indian Academy of Sciences (India)

    Abstract. We review two methods discussed in the literature to determine the effective parameters of strongly interacting particles as they move through a heat bath. The first one is the general method of chiral perturbation theory, which may be readily applied to this problem. The other is the method of thermal QCD sum rules ...

  6. Strong-strong beam-beam simulation on parallel computer

    Energy Technology Data Exchange (ETDEWEB)

    Qiang, Ji


    The beam-beam interaction puts a strong limit on the luminosity of the high energy storage ring colliders. At the interaction points, the electromagnetic fields generated by one beam focus or defocus the opposite beam. This can cause beam blowup and a reduction of luminosity. An accurate simulation of the beam-beam interaction is needed to help optimize the luminosity in high energy colliders.

  7. Strong-strong beam-beam simulation on parallel computer

    International Nuclear Information System (INIS)

    Qiang, Ji


    The beam-beam interaction puts a strong limit on the luminosity of the high energy storage ring colliders. At the interaction points, the electromagnetic fields generated by one beam focus or defocus the opposite beam. This can cause beam blowup and a reduction of luminosity. An accurate simulation of the beam-beam interaction is needed to help optimize the luminosity in high energy colliders

  8. Serum alkaline phosphatase screening for vitamin D deficiency states

    International Nuclear Information System (INIS)

    Shaheen, S.; Barrakzai, Q.


    Objective: To determine whether serum vitamin D levels are correlated with serum levels of alkaline phosphatase or not. Study Design: Cross-sectional, observational study. Place and Duration of Study: Multi-centre study, conducted at Liaquat National Hospital and Medical College, National Medical Centre and Medicare Hospital, Karachi, from January to October 2009. Methodology: Patients attending the Orthopaedic OPDs with complaints of pain in different body regions and serum vitamin D/sub 3/ levels of greater or equal to 30 ng/ml were included in the study. Patients with vitamin D deficiency were further categorized into mild deficiency or insufficiency (vit. D/sub 3/ = 20-29 ng/ml), moderate deficiency (vit. D/sub 3/ = 5 - 19 ng/ml) and severe deficiency forms (vit. D/sub 3/ < 5 ng/ml). Pearson correlation was applied to test the correlation of serum alkaline phosphatase levels with serum vitamin D/sub 3/ levels. P-value < 0.05 was considered to be significant. Results: Out of 110 samples, 26 had mild (23%), 61 had moderate (55%) and 21 had severe (19.1%) vitamin D deficiencies. All of the patients in the three groups had alkaline phosphatase with in normal limits and the total mean value of the enzyme was 135.97 +- 68.14I U/L. The inter group comparison showed highest values of alkaline phosphatase in the moderate vitamin D deficiency group. The correlation coefficient of alkaline phosphatase and serum vitamin D/sub 3/ levels was r =0.05 (p =0.593). Conclusion: Serum vitamin D/sub 3/ levels may not be correlated with increased serum alkaline phosphatase levels. Therefore, alkaline phosphatase may not be used as a screening test to rule out vitamin D deficiency. (author)

  9. Conditioning alkaline coolant radioactive waste from research reactor BR-10

    International Nuclear Information System (INIS)

    Vladimir, Smykov; Mikhail, Kononyuk; Kirill, Butov


    In the Institute for Physics and Power Engineering (Russia) has developed and was successfully demonstrated a technology of solid-phase oxidation of alkaline metal by slag from the copper-smelting industry. Neutralization of alkaline metal in the solid-phase oxidation process occurs in a single phase. The solid-phase oxidation process does not result in the generation of hydrogen. The product of alkaline metal radioactive waste processing is solid mineral-like sinter of reaction products, contained inside a steel reaction container, which is immediately shipped for dry storage in a solid radioactive waste storage facility. The presence of a mercury admixture in the research reactor BR-10 (BR-10) reactor alkaline metals radioactive waste makes conditioning of that waste considerably more complicated. Laboratory research demonstrated that mercury could be effectively removed from alkaline metal by pushing the Na-K alloy through chips of metallic magnesium in elevated temperatures. For neutralization of non-drainable sodium residues and admixtures in individual equipment (cold traps, pipe lines, tanks) of the research reactor BR-10 has developed a method for neutralization of non-drainable residues of alkaline liquid metal coolants with a gaseous sub oxide of nitrogen, which is characterized by absence of hydrogen generation, improving the safety of the technology. Currently, the reactor building is undergoing installation of the experimental-industrial plant 'Magma', the purpose of which is processing of accumulated alkaline metals radioactive waste. In according with concept of 'experimental polygon for testing the decommissioning technologies of the BN series of reactors' based on the BR-10 installation, it would appear sensible to start the development of the installation for conditioning by solid-phase oxidation of up to 1000 liters of radioactive waste per loading. (author)

  10. Reduction of nitrobenzene with alkaline ascorbic acid: Kinetics and pathways

    International Nuclear Information System (INIS)

    Liang, Chenju; Lin, Ya-Ting; Shiu, Jia-Wei


    Highlights: • Alkaline ascorbic acid (a.k.a. vitamin C) is capable of reductively degrading NB. • The pH above the pK a2 of ascorbic acid increases reductive electron transfer to NB. • The rate equation for the reactions between NB and AA is determined. • NSB, AZOXY, and AZO are identified as intermediates and aniline as a final product. • Alkaline pH is essential for AA remediation of NB contaminated soils. - Abstract: Alkaline ascorbic acid (AA) exhibits the potential to reductively degrade nitrobenzene (NB), which is the simplest of the nitroaromatic compounds. The nitro group (NO 2 − ) of NB has a +III oxidation state of the N atom and tends to gain electrons. The effect of alkaline pH ranging from 9 to 13 was initially assessed and the results demonstrated that the solution pH, when approaching or above the pK a2 of AA (11.79), would increase reductive electron transfer to NB. The rate equation for the reactions between NB and AA at pH 12 can be described as r = ((0.89 ± 0.11) × 10 −4 mM 1−(a + b) h −1 ) × [NB] a = 1.35 ± 0.10 [AA] b = 0.89 ± 0.01 . The GC/MS analytical method identified nitrosobenzene, azoxybenzene, and azobenzene as NB reduction intermediates, and aniline (AN) as a final product. These experimental results indicate that the alkaline AA reduction of NB to AN mainly proceeds via the direct route, consisting of a series of two-electron or four-electron transfers, and the condensation reaction plays a minor route. Preliminary evaluation of the remediation of spiked NB contaminated soils revealed that maintenance of alkaline pH and a higher water to soil ratio are essential for a successful alkaline AA application.

  11. Evaluation of some bean lines tolerance to alkaline soil

    Directory of Open Access Journals (Sweden)

    Abeer A. Radi


    Full Text Available Introduction: In less arid climates, salts are less concentrated and sodium dominates in carbonate and bicarbonate forms, which enhance the formation of alkaline soils. The development and identification of salt-tolerant crop cultivars or lines would complement salt management programs to improve the productivity and yields of salt stressed plants.Materials and methods: This work was to study the evaluation of alkalinity tolerance of some bean lines grown under different levels of sodium carbonate (Na2CO3 to select the most alkalinity tolerant lines versus the most-sensitive ones out of 6 lines of the test plants.Results: The symptoms induced by alkalinity included reduction in root, shoot growth, and leaf area which were more severe in some bean lines. Potassium leakage was severely affected by alkalinity in some lines at all tested levels, while in some others a moderate damage was manifested only at the higher levels. The increase in Na2CO3 level was associated with a gradual fall in chlorophyll a and b biosynthesis of all the test bean lines. However, alkalinity at low and moderate levels had a favorable effect on the biosynthesis of carotenoids in all the test bean lines. The increase in Na2CO3 supply had a considerable stimulatory effect on sodium accumulation, while potassium accumulation fluctuated in organs of bean lines.Conclusion: Assiut 1104 out of all the different lines investigated was found to display the lowest sensitivity to alkalinity stress, while Assiut 12/104 was the most sensitive one.

  12. Advanced alkaline water electrolysis. Task 2 summary report. Model for alkaline water electrolysis systems

    Energy Technology Data Exchange (ETDEWEB)

    Yaffe, M.R.; Murray, J.N.


    Task 2 involved the establishment of an engineering and economic model for the evaluation of various options in water electrolysis. The mode, verification of the specific coding and four case studies are described. The model was tested by evaluation of a nearly commercial technology, i.e., an 80-kW alkaline electrolyte system, operating at 60/sup 0/C, which delivers approximately 255 SLM, hydrogen for applications such as electrical generation cooling or semiconductor manufacturing. The calculated cost of hydrogen from this installed non-optimized case system with an initial cost to the customer of $87,000 was $6.99/Kg H/sub 2/ ($1.67/100 SCF) on a 20-yr levelized basis using 2.5 cents/kWh power costs. This compares favorably to a levelized average merchant hydrogen cost value of $9.11/Kg H/sub 2/ ($2.17/100 SCF) calculated using the same program.

  13. PREFACE: Strongly correlated electron systems Strongly correlated electron systems (United States)

    Saxena, Siddharth S.; Littlewood, P. B.


    This special section is dedicated to the Strongly Correlated Electron Systems Conference (SCES) 2011, which was held from 29 August-3 September 2011, in Cambridge, UK. SCES'2011 is dedicated to 100 years of superconductivity and covers a range of topics in the area of strongly correlated systems. The correlated electronic and magnetic materials featured include f-electron based heavy fermion intermetallics and d-electron based transition metal compounds. The selected papers derived from invited presentations seek to deepen our understanding of the rich physical phenomena that arise from correlation effects. The focus is on quantum phase transitions, non-Fermi liquid phenomena, quantum magnetism, unconventional superconductivity and metal-insulator transitions. Both experimental and theoretical work is presented. Based on fundamental advances in the understanding of electronic materials, much of 20th century materials physics was driven by miniaturisation and integration in the electronics industry to the current generation of nanometre scale devices. The achievements of this industry have brought unprecedented advances to society and well-being, and no doubt there is much further to go—note that this progress is founded on investments and studies in the fundamentals of condensed matter physics from more than 50 years ago. Nevertheless, the defining challenges for the 21st century will lie in the discovery in science, and deployment through engineering, of technologies that can deliver the scale needed to have an impact on the sustainability agenda. Thus the big developments in nanotechnology may lie not in the pursuit of yet smaller transistors, but in the design of new structures that can revolutionise the performance of solar cells, batteries, fuel cells, light-weight structural materials, refrigeration, water purification, etc. The science presented in the papers of this special section also highlights the underlying interest in energy-dense materials, which


    Directory of Open Access Journals (Sweden)

    Cuilan Li


    Full Text Available Humic substances are the major components of soil organic matter. Among the three humic substance components (humic acid, fulvic acid, and humin, humin is the most insoluble in aqueous solution at any pH value and, in turn, the least understood. Humin has poor solubility mainly because it is tightly bonded to inorganic soil colloids. By breaking the linkage between humin and inorganic soil colloids using inorganic or organic solvents, bulk humin can be partially soluble in alkali, enabling a better understanding of the structure and properties of humin. However, the structural relationship between bulk humin and its alkaline-soluble (AS and alkaline-insoluble (AIS fractions is still unknown. In this study, we isolated bulk humin from two soils of Northeast China by exhaustive extraction (25 to 28 times with 0.1 mol L-1 NaOH + 0.1 mol L-1 Na4P2O7, followed by the traditional treatment with 10 % HF-HCl. The isolated bulk humin was then fractionated into AS-humin and AIS-humin by exhaustive extraction (12 to 15 times with 0.1 mol L-1 NaOH. Elemental analysis and solid-state 13C cross-polarization magic angle spinning nuclear magnetic resonance (13C CPMAS NMR spectroscopy were used to characterize and compare the chemical structures of bulk humin and its corresponding fractions. The results showed that, regardless of soil types, bulk humin was the most aliphatic and most hydrophobic, AS-humin was the least aliphatic, and AIS-humin was the least alkylated among the three humic components. The results showed that bulk humin and its corresponding AS-humin and AIS-humin fractions are structurally differed from one another, implying that the functions of these humic components in the soil environment differed.

  15. Monitoring polariton dynamics in the LHCII photosynthetic antenna in a microcavity by two-photon coincidence counting (United States)

    Zhang, Zhedong; Saurabh, Prasoon; Dorfman, Konstantin E.; Debnath, Arunangshu; Mukamel, Shaul


    The relaxation dynamics of light-harvesting complex II in an optical cavity is explored theoretically by multidimensional photon coincidence counting spectroscopy. This technique reveals the dynamics in both single (e) and double (f) excitation bands. We study how the polariton dynamics are affected by coupling to photon modes and molecular vibrations described by a realistic spectral density at 77 K. Without the cavity, the e- and f-band energy transfer pathways are not clearly resolved due to the line broadening caused by fast exciton dephasing. The strong coupling to cavity photons results in well-resolved polariton modes. The hybrid nature of polaritons slows down their energy transfer rates.

  16. Strongly correlated systems experimental techniques

    CERN Document Server

    Mancini, Ferdinando


    The continuous evolution and development of experimental techniques is at the basis of any fundamental achievement in modern physics. Strongly correlated systems (SCS), more than any other, need to be investigated through the greatest variety of experimental techniques in order to unveil and crosscheck the numerous and puzzling anomalous behaviors characterizing them. The study of SCS fostered the improvement of many old experimental techniques, but also the advent of many new ones just invented in order to analyze the complex behaviors of these systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and materials science, belong to this class of systems. The volume presents a representative collection of the modern experimental techniques specifically tailored for the analysis of strongly correlated systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognize...

  17. Strongly Correlated Systems Theoretical Methods

    CERN Document Server

    Avella, Adolfo


    The volume presents, for the very first time, an exhaustive collection of those modern theoretical methods specifically tailored for the analysis of Strongly Correlated Systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and materials science, belong to this class of systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognized main contributors. The exposition has a clear pedagogical cut and fully reports on the most relevant case study where the specific technique showed to be very successful in describing and enlightening the puzzling physics of a particular strongly correlated system. The book is intended for advanced graduate students and post-docs in the field as textbook and/or main reference, but also for other researchers in the field who appreciates consulting a single, but comprehensive, source or wishes to get acquainted, in a as painless as po...

  18. Strongly correlated systems numerical methods

    CERN Document Server

    Mancini, Ferdinando


    This volume presents, for the very first time, an exhaustive collection of those modern numerical methods specifically tailored for the analysis of Strongly Correlated Systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and material science, belong to this class of systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognized main contributors. The exposition has a clear pedagogical cut and fully reports on the most relevant case study where the specific technique showed to be very successful in describing and enlightening the puzzling physics of a particular strongly correlated system. The book is intended for advanced graduate students and post-docs in the field as textbook and/or main reference, but also for other researchers in the field who appreciate consulting a single, but comprehensive, source or wishes to get acquainted, in a as painless as possi...

  19. Strongly nonlinear oscillators analytical solutions

    CERN Document Server

    Cveticanin, Livija


    This book provides the presentation of the motion of pure nonlinear oscillatory systems and various solution procedures which give the approximate solutions of the strong nonlinear oscillator equations. The book presents the original author’s method for the analytical solution procedure of the pure nonlinear oscillator system. After an introduction, the physical explanation of the pure nonlinearity and of the pure nonlinear oscillator is given. The analytical solution for free and forced vibrations of the one-degree-of-freedom strong nonlinear system with constant and time variable parameter is considered. Special attention is given to the one and two mass oscillatory systems with two-degrees-of-freedom. The criteria for the deterministic chaos in ideal and non-ideal pure nonlinear oscillators are derived analytically. The method for suppressing chaos is developed. Important problems are discussed in didactic exercises. The book is self-consistent and suitable as a textbook for students and also for profess...

  20. Flavour Democracy in Strong Unification

    CERN Document Server

    Abel, S A; Abel, Steven; King, Steven


    We show that the fermion mass spectrum may naturally be understood in terms of flavour democratic fixed points in supersymmetric theories which have a large domain of attraction in the presence of "strong unification". Our approach provides an alternative to the approximate Yukawa texture zeroes of the Froggatt-Nielsen mechanism. We discuss a particular model based on a broken gauged $SU(3)_L\\times SU(3)_R$ family symmetry which illustrates our approach.

  1. Investigating Mechanisms of Alkalinization for Reducing Primary Breast Tumor Invasion

    Directory of Open Access Journals (Sweden)

    Ian F. Robey


    Full Text Available The extracellular pH (pHe of many solid tumors is acidic as a result of glycolytic metabolism and poor perfusion. Acidity promotes invasion and enhances metastatic potential. Tumor acidity can be buffered by systemic administration of an alkaline agent such as sodium bicarbonate. Tumor-bearing mice maintained on sodium bicarbonate drinking water exhibit fewer metastases and survive longer than untreated controls. We predict this effect is due to inhibition of tumor invasion. Reducing tumor invasion should result in fewer circulating tumor cells (CTCs. We report that bicarbonate-treated MDA-MB-231 tumor-bearing mice exhibited significantly lower numbers of CTCs than untreated mice (. Tumor pHe buffering may reduce optimal conditions for enzymes involved in tumor invasion such as cathepsins and matrix metalloproteases (MMPs. To address this, we tested the effect of transient alkalinization on cathepsin and MMP activity using enzyme activatable fluorescence agents in mice bearing MDA-MB-231 mammary xenografts. Transient alkalinization significantly reduced the fluorescent signal of protease-specific activatable agents in vivo (. Alkalinization, however, did not affect expression of carbonic anhydrase IX (CAIX. The findings suggest a possible mechanism in a live model system for breast cancer where systemic alkalinization slows the rate of invasion.

  2. Elevated serum level of human alkaline phosphatase in obesity. (United States)

    Khan, Abdul Rehman; Awan, Fazli Rabbi; Najam, Syeda Sadia; Islam, Mehboob; Siddique, Tehmina; Zain, Maryam


    To investigate a correlation between serum alkaline phosphatase level and body mass index in human subjects. The comparative cross-sectional study was carried out at the National Institute for Biotechnology and Genetic Engineering, Faisalabad, Pakistan, from April 2012 to June 2013. Blood serum alkaline phosphatase levels were estimated and the subjects were divided into three sub-groups on the basis of their body mass. normal weight (27kg/m2) subjects. The serum samples were used for the estimation of clinically important biochemical parameters, using commercial kits on clinical chemistry analyser. Of the 197 subjects, 97(49%) were obese and 100(51%) were non-obese. The serum alkaline phosphatase level increased in obese (214±6.4 IU/L) compared to the non-obese subjects (184.5±5 IU/L). Furthermore, a significant linear relationship (r=0.3;p-0.0001) was found between serum alkaline phosphatase and body mass index. Other biochemical variables were not correlated to the body mass index. Over activity and higher amounts of alkaline phosphatase were linked to the development of obesity.

  3. Elevated Serum Level of Human Alkaline Phosphatase in Obesity

    International Nuclear Information System (INIS)

    Khan, A. R.; Awan, F. R.; Najam, S. S.; Islam, M.; Siddique, T.; Zain, M.


    Objective: To investigate a correlation between serum alkaline phosphatase level and body mass index in human subjects. Methods: The comparative cross-sectional study was carried out at the National Institute for Biotechnology and Genetic Engineering, Faisalabad, Pakistan, from April 2012 to June 2013. Blood serum alkaline phosphatase levels were estimated and the subjects were divided into three sub-groups on the basis of their body mass index: normal weight (<25kg/m2), overweight (25-27kg/m2) and obese (>27kg/m2) subjects. The serum samples were used for the estimation of clinically important biochemical parameters, using commercial kits on clinical chemistry analyser. Results: Of the 197 subjects, 97(49 percent) were obese and 100(51 percent) were non-obese. The serum alkaline phosphatase level increased in obese (214±6.4 IU/L) compared to the non-obese subjects (184.5±5 IU/L). Furthermore, a significant linear relationship (r=0.3;p-0.0001) was found between serum alkaline phosphatase and body mass index. Other biochemical variables were not correlated to the body mass index. Conclusion: Over activity and higher amounts of alkaline phosphatase were linked to the development of obesity. (author)

  4. Synergistic degradation of konjac glucomannan by alkaline and thermal method. (United States)

    Jin, Weiping; Mei, Ting; Wang, Yuntao; Xu, Wei; Li, Jing; Zhou, Bin; Li, Bin


    The application of konjac glucomannan (KGM) in the food industry is always limited by its high viscosity. Hereby, low-viscosity KGM was prepared by alkaline-thermal degradation method. This process was demonstrated by the changes of average molecular weight and a kinetic model was developed. The results revealed that high alkalinity and high temperature had a synergetic effect on degradation. The structure of hydrolysates was evaluated by periodate oxidation and their fluidly properties were researched by rheology measurements. The degradation was divided into two regimes. The rate of the first regime (within 1h) is higher than that of the second one (last 1h). It is found that alkaline hydrolysis and deacetylation have a synergistic effect on the degradation under high alkalinity (pH 9.2) and low temperature condition (25 °C). Finally, rheology parameters showed alkaline-thermal degradation is a promising way that can be applied in practice to degrade KGM. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Petrogenesis of Karamaili alkaline A-type granites from East Junggar, Xinjiang (NW China) and their relationship with tin mineralization

    International Nuclear Information System (INIS)

    Su Yuping; Tang Hongfeng; Liu Congqiang; Hou Guangshun; Cong Feng; Sylvester, Paul J.; Qu Wenjun


    Several types of granites including alkaline granites and alkali feldspar granites are distributed in the Karamaili tectonic belt of East Junggar, Xinjiang, China. Some medium-small tin deposits are located within or near the contact zones of the granitic intrusions. The alkaline granites share all the features commonly observed in peralkaline A-type granites. They contain alkalic mafic minerals such as riebeckite and aegirine; have high contents of SiO 2 , alkalis, Rb, Th, Zr, Hf, REE (except Eu), and high ratios of FeO/MgO and Ga/Al; and show strong depletions in Ba, Sr, Eu in the spidergrams. Laser ablation-ICPMS U-Pb zircon geochronology indicates a crystallization age of ca. 305 Ma for the granites; TIMS analyses of the granites found high ε Nd (T) values of +5.9 to +6.5. Considering their geochemical features, alkaline granites most likely formed by fractional crystallization of graodioritic magmas, which were probably produced by partial melting of lower crustal basaltic to andesitic rocks formed from oceanic crustal materials that were deeply buried during late Palezoic subduction and accretion. Six molybdenite samples from the Sareshike tin deposit in East Junggar yielded an isochron age of 307±11 Ma (2σ) and a weighted mean model age of 306.5±3.4 Ma, consistent with zircon U-Pb ages of the alkaline granites. Low Re contents (0.323-0.961 ppm) in the molybdenite suggest that they originated from crustal sources related to the alkaline granites. Considering their identical ages, close spatial distribution, and similar sources, we argue that the A-type granites have a genetic relationship with the tin mineralization, and that the same association may be important elsewhere. (author)

  6. Actinide-Aluminate Speciation in Alkaline Radioactive Waste

    Energy Technology Data Exchange (ETDEWEB)

    Dr. David L. Clark; Dr. Alexander M. Fedosseev


    Investigation of behavior of actinides in alkaline media containing AL(III) showed that no aluminate complexes of actinides in oxidation states (IIII-VIII) were formed in alkaline solutions. At alkaline precipitation IPH (10-14) of actinides in presence of AL(III) formation of aluminate compounds is not observed. However, in precipitates contained actinides (IIV)<(VI), and to a lesser degree actinides (III), some interference of components takes place that is reflected in change of solid phase properties in comparison with pure components or their mechanical mixture. The interference decreases with rise of precipitation PH and at PH 14 is exhibited very feebly. In the case of NP(VII) the individual compound with AL(III) is obtained, however it is not aluminate of neptunium(VII), but neptunate of aluminium(III) similar to neptunates of other metals obtained earlier.

  7. Decadal Variability of Total Alkalinity in the North Pacific Ocean (United States)

    Cross, J. N.; Carter, B. R.; Siedlecki, S. A.; Alin, S. R.; Dickson, A. G.; Feely, R. A.; Mathis, J. T.; Wanninkhof, R. H.; Macdonald, A. M.; Mecking, S.; Talley, L. D.


    Recent observations of acidification-driven shoaling of the calcium carbonate saturation horizon in the North Pacific have prompted new interest in carbonate cycling in this region, particularly related to impacts on biogenic calcification at the surface layer. Some estimates project that the impacts of OA on alkalinity cycling are beginning to emerge. Here, we present total alkalinity concentrations along a meridional transect of the North Pacific (WOCE, CLIVAR, and US GO-SHIP line P16N; 152 °W) over a period of three decades. The largest source of variability in alkalinity concentrations is related to North Pacific circulation, particularly in the surface mixed layer. Precise normalization of these data reveal some small spatial and temporal variability in the background. We explore these decadal trends in the context of decadal oscillations, ocean biogeochemical cycles, and global change processes such as ocean acidification.

  8. Americium extraction by alkylpyrocatechin from alkaline salt solutions

    International Nuclear Information System (INIS)

    Karalova, Z.K.; Rodionova, L.M.; Myasoedov, B.F.


    Effect of iron, aluminium, calcium, and sodium nitrates on americium extraction by 0.1 mol/l DOP solution [4-(α-α dioctylethyl) pyrocatechin] in toluene from a mixture of 2 mol/l NaOH with 0.1 mol/l EDTA has been investigated. It has been shown that americium extraction does not change essen-- tially in the presence of salts that permits to use DOP for Am extraction from alkaline solutions in the presence of outside salts. Verification of the above method of extraction of radioactive isotopes has been carried out. According to the data obtained double extraction provides a preparation of alkaline solutions practically free from radioactive isotopes. DOP application for Am extraction from alkaline salt solutions allows one to carry out repeated Am concentration and separation from accompanying elements. Conditions, under which Fe(3)-Am(3) pair separation coefficient achieves nx10 2 -10 4 , have been found out

  9. Neutral and alkaline cellulases: Production, engineering, and applications. (United States)

    Ben Hmad, Ines; Gargouri, Ali


    Neutral and alkaline cellulases from microorganisms constitute a major group of the industrial enzymes and find applications in various industries. Screening is the important ways to get novel cellulases. Most fungal cellulases have acidic pH optima, except some fungi like Humicola insolens species. However, new applications require the use of neutral and alkaline cellulases in food, brewery and wine, animal feed, textile and laundry, pulp and paper industries, agriculture as well in scientific research purposes. Indeed, the demand for these enzymes is growing more rapidly than ever before, and becomes the driving force for research on engineering the cellulolytic enzymes. Here, we present an overview of the biotechnological research for neutral and alkaline cellulases. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Mineral CO2 sequestration in alkaline solid residues

    International Nuclear Information System (INIS)

    Huijgen, W.J.J.; Comans, R.N.J.; Witkamp, G.J.


    Mineral carbonation is a promising sequestration route for the permanent and safe storage of carbon dioxide. In addition to calcium- or magnesium-containing primary minerals, suitable alkaline solid residues can be used as feedstock. The use of alkaline residues has several advantages, such as their availability close to CO2 sources and their higher reactivity for carbonation than primary minerals. In addition, the environmental quality of residues can potentially be improved by carbonation. In this study, key factors of the mineral CO2 sequestration process are identified, their influence on the carbonation process is examined, and environmental properties of the reaction products with regard to their possible beneficial utilization are investigated. The use of alkaline solid residues forms a potentially attractive alternative for the first mineral sequestration plants

  11. Mineral Element Concentrations in Vegetables Cultivated in Acidic Compared to Alkaline Areas of South Sweden

    Directory of Open Access Journals (Sweden)

    Ingegerd Rosborg


    Full Text Available A study in 1997, on mineral levels in acidic compared to alkaline well waters, and in women’s hair, revealed higher concentrations of a number of mineral elements like Ca, Mo and Se in alkaline waters and hair. Thus, median Ca levels were six times higher in well water and five times higher in hair from the alkaline area compared to the acidic area. This finding raised the probability of similar differences in vegetables from these areas. Thus, in the year 2006, 60 women who had participated in the study in 1997 were asked to cultivate parsley, lettuce, carrot and chive. During the spring of 2006, the women from the water and hair study of 1997, 30 of them from the acidic area and 30 women from the alkaline district cultivated vegetables: carrot (Daucus carota L, parsley (Petroselinum crispum, chive (Allium schoenoprasum and lettuce (Eruca sativa. The vegetables were harvested, and rinsed in tap water from the kitchens of the participating women in August. The concentrations of about 35 elements and ions were determined by ICP OES and ICP-MS predominantly. In addition, soil samples from the different cultivators were also analyzed for a number of elements. Lettuce and parsley showed the highest concentrations of mineral elements per gram dry weight. Only Mo concentrations were significantly higher in all the different vegetables from the alkaline district compared to vegetables from the acidic areas. On the other hand, the concentrations of Ba, Br, Mn, Rb and Zn were higher in all the different vegetables from the acidic area. In the soil, only pH and exchangeable Ca from the alkaline area were higher than from the acidic area, while exchangeable Fe, Mn and Na concentrations were higher in soils from the acidic area. Soil elements like Al, Fe, Li, Ni, Pb, Si, Ti, V, Zn and Zr were found in higher concentrations in lettuce and parsley, which were attributed to soil particles being splashed on the plants by the rain and absorbed by the leaves

  12. Efficient acquisition of iron confers greater tolerance to saline-alkaline stress in rice (Oryza sativa L.). (United States)

    Li, Qian; Yang, An; Zhang, Wen-Hao


    To elucidate the mechanisms underlying tolerance to saline-alkaline stress in two rice genotypes, Dongdao-4 and Jigeng-88, we exposed them to medium supplemented with 10 mM Na 2 CO 3 and 40 mM NaCl (pH 8.5). Dongdao-4 plants displayed higher biomass, chlorophyll content, and photosynthetic rates, and a larger root system than Jigeng-88 under saline-alkaline conditions. Dongdao-4 had a higher shoot Na + /K + ratio than Jigeng-88 under both control and saline-alkaline conditions. Dongdao-4 exhibited stronger rhizospheric acidification than Jigeng-88 under saline-alkaline conditions, resulting from greater up-regulation of H + -ATPases at the transcriptional level. Moreover, Fe concentrations in shoots and roots of Dongdao-4 were higher than those in Jigeng-88, and a higher rate of phytosiderophore exudation was detected in Dongdao-4 versus Jigeng-88 under saline-alkaline conditions. The Fe-deficiency-responsive genes OsIRO2, OsIRT1, OsNAS1, OsNAS2, OsYSL2, and OsYSL15 were more strongly up-regulated in Dongdao-4 than Jigeng-88 plants in saline-alkaline medium, implying greater tolerance of Dongdao-4 plants to Fe deficiency. To test this hypothesis, we compared the effects of Fe deficiency on the two genotypes, and found that Dongdao-4 was more tolerant to Fe deficiency. Exposure to Fe-deficient medium led to greater rhizospheric acidification and phytosiderophore exudation in Dongdao-4 than Jigeng-88 plants. Expression levels of OsIRO2, OsIRT1, OsNAS1, OsNAS2, OsYSL2, and OsYSL15 were higher in Dongdao-4 than Jigeng-88 plants under Fe-deficient conditions. These results demonstrate that a highly efficient Fe acquisition system together with a large root system may underpin the greater tolerance of Dongdao-4 plants to saline-alkaline stress. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  13. Driving force for the hydration of the swelling clays: Case of montmorillonites saturated with alkaline-earth cations

    International Nuclear Information System (INIS)

    Salles, Fabrice; Douillard, Jean-Marc; Gaudin, Cedric; Prelot, Benedicte; Zajac, Jerzy; Bildstein, Olivier; Van Damme, Henri


    Important structural modifications occur in swelling clays upon water adsorption. The multi-scale evolution of the swelling clay structure is usually evidenced by various experimental techniques. However, the driving force behind such phenomena is still not thoroughly understood. It appears strongly dependent on the nature of the interlayer cation. In the case of montmorillonites saturated with alkaline cations, it was inferred that the compensating cation or the layer surface could control the hydration process and thus the opening of the interlayer space, depending on the nature of the interlayer cation. In the present study, emphasis is put on the impact of divalent alkaline-earth cations compensating the layer charge in montmorillonites. Since no experimental technique offers the possibility of directly determining the hydration contributions related to interlayer cations and layer surfaces, an approach based on the combination of electrostatic calculations and immersion data is developed here, as already validated in the case of montmorillonites saturated by alkaline cations. This methodology allows to estimate the hydration energy for divalent interlayer cations and therefore to shed a new light on the driving force for hydration process occurring in montmorillonites saturated with alkaline-earth cations. Firstly, the surface energy values obtained from the electrostatic calculations based on the Electronegativity Equalization Method vary from 450 mJ m -2 for Mg-montmorillonite to 1100 mJ m -2 for Ba-montmorillonite. Secondly, considering both the hydration energy for cations and layer surfaces, the driving force for the hydration of alkaline-earth saturated montmorillonites can be attributed to the interlayer cation in the case of Mg-, Ca-, Sr-montmorillonites and to the interlayer surface in the case of Ba-montmorillonites. These results explain the differences in behaviour upon water adsorption as a function of the nature of the interlayer cation, thereby

  14. Atoms in strong laser fields

    International Nuclear Information System (INIS)

    L'Huillier, A.


    When a high-power laser focuses into a gas of atoms, the electromagnetic field becomes of the same magnitude as the Coulomb field which binds a 1s electron in a hydrogen atom. 3 highly non-linear phenomena can happen: 1) ATI (above threshold ionization): electrons initially in the ground state absorb a large number of photons, many more than the minimum number required for ionization; 2) multiple ionization: many electrons can be emitted one at a time, in a sequential process, or simultaneously in a mechanism called direct or non-sequential; and 3) high order harmonic generation (HHG): efficient photon emission in the extreme ultraviolet range, in the form of high-order harmonics of the fundamental laser field can occur. The theoretical problem consists in solving the time dependent Schroedinger equation (TDSE) that describes the interaction of a many-electron atom with a laser field. A number of methods have been proposed to solve this problem in the case of a hydrogen atom or a single-active electron atom in a strong laser field. A large effort is presently being devoted to go beyond the single-active approximation. The understanding of the physics of the interaction between atoms and strong laser fields has been provided by a very simple model called ''simple man's theory''. A unified view of HHG, ATI, and non-sequential ionization, originating from the simple man's model and the strong field approximation, expressed in terms of electrons trajectories or quantum paths is slowly emerging. (A.C.)

  15. Alkalinity production in intertidal sands intensified by lugworm bioirrigation. (United States)

    Rao, Alexandra M F; Malkin, Sairah Y; Montserrat, Francesc; Meysman, Filip J R


    Porewater profiles and sediment-water fluxes of oxygen, nutrients, pH, calcium, alkalinity, and sulfide were measured in intertidal sandflat sediments from the Oosterschelde mesotidal lagoon (The Netherlands). The influence of bioturbation and bioirrigation by the deep-burrowing polychaete Arenicola marina on the rates and sources of benthic alkalinity generation was examined by comparing measurements in intact and defaunated sediment cores before and after the addition of A. marina in summer and fall 2011. Higher organic matter remineralization rates, shallower O 2 penetration, and greater sediment-water solute fluxes were observed in summer, consistent with higher sediment community metabolic rates at a higher temperature. Lugworm activity stimulated porewater exchange (5.1 × in summer, 1.9 × in fall), organic matter remineralization (6.2 × in summer, 1.9 × in fall), aerobic respiration (2.4 × in summer, 2.1 × in fall), alkalinity release (4.7 × in summer, 4.0 × in fall), nutrient regeneration, and iron cycling. The effects of lugworm activity on net sediment-water fluxes were similar but more pronounced in summer than in fall. Alkalinity release in fall was entirely driven by metabolic carbonate dissolution, while this process explained between 22 and 69% of total alkalinity production in summer, indicating the importance of other processes in this season. By enhancing organic matter remineralization and the reoxidation of reduced metabolites by the sediment microbial community, lugworm activity stimulated the production of dissolved inorganic carbon and metabolic acidity, which in turn enhanced metabolic CaCO 3 dissolution efficiency. In summer, evidence of microbial long distance electron transport (LDET) was observed in defaunated sediment. Thus, alkalinity production by net carbonate dissolution was likely supplemented by anaerobic respiration and LDET in summer.

  16. Geology and petrology of Lages Alkaline District, Santa Catarina State

    International Nuclear Information System (INIS)

    Scheibe, L.F.


    A 1:100.000 geological map shows the main outcrops, covering about 50 Km 2 , of the leucocratic alkaline rocks, ultra basic alkaline rocks, carbonatites and volcanic breccias which intruded the Gondwanic sedimentary rocks within a short time interval and characterize the Alkaline District of Lages. Chemical analyses of 33 whole-rock samples confirm the petrographic classification, but the agpaitic indexes, mostly below 1.0, do not reflect the mineralogical variations of the leucocratic alkaline rocks adequately. Partial REE analyses indicate that the light as well as the heavy rare earth contents decrease from the basic to the more evolved rocks, the La/Y ratio remaining approximately constant. Eleven new K/Ar ages from porphyritic nepheline syenites porphyritic phonolites, ultra basic alkaline rocks and pipe-breccias, together with six already available ages, show a major concentration in the range 65 to 75 Ma, with a mode at ca. 70 Ma. But one Rb/Sr whole-rock reference isochron diagram gives an age of 82+-6 Ma for the agpaitic phonolites of the Serra Chapada, which are considered younger than the miaskitic porphyriric nepheline syenites. The 87 Sr/ 86 Sr ratios of 0.705-0.706 are compatible with a sub continental mantelic origin, devoid of crustal contamination. A petrogenetic model based on subtraction diagrams and taking into consideration the geologic, petrographic, mineralogic and petrochemical characteristics of the alkaline rocks of Lages consists of limited partial melting with CO 2 , contribution of the previously metasomatized upper mantle, in a region submitted to decompression. (author)

  17. Strongly Interacting Light Dark Matter

    Directory of Open Access Journals (Sweden)

    Sebastian Bruggisser, Francesco Riva, Alfredo Urbano


    Full Text Available In the presence of approximate global symmetries that forbid relevant interactions, strongly coupled light Dark Matter (DM can appear weakly coupled at small energy and generate a sizable relic abundance. Fundamental principles like unitarity restrict these symmetries to a small class, where the leading interactions are captured by effective operators up to dimension-8. Chiral symmetry, spontaneously broken global symmetries and non-linearly realized supersymmetry are examples of this. Their DM candidates (composite fermions, pseudo Nambu-Goldstone Bosons and Goldstini are interesting targets for LHC missing-energy searches.

  18. Strongly interacting light dark matter

    International Nuclear Information System (INIS)

    Bruggisser, Sebastian; Riva, Francesco; Urbano, Alfredo


    In the presence of approximate global symmetries that forbid relevant interactions, strongly coupled light Dark Matter (DM) can appear weakly coupled at small-energy and generate a sizable relic abundance. Fundamental principles like unitarity restrict these symmetries to a small class, where the leading interactions are captured by effective operators up to dimension-8. Chiral symmetry, spontaneously broken global symmetries and non-linearly realized supersymmetry are examples of this. Their DM candidates (composite fermions, pseudo-Nambu-Goldstone Bosons and Goldstini) are interesting targets for LHC missing-energy searches.

  19. Rydberg atoms in strong fields

    International Nuclear Information System (INIS)

    Kleppner, D.; Tsimmerman, M.


    Experimental and theoretical achievements in studying Rydberg atoms in external fields are considered. Only static (or quasistatic) fields and ''one-electron'' atoms, i.e. atoms that are well described by one-electron states, are discussed. Mainly behaviour of alkali metal atoms in electric field is considered. The state of theoretical investigations for hydrogen atom in magnetic field is described, but experimental data for atoms of alkali metals are presented as an illustration. Results of the latest experimental and theoretical investigations into the structure of Rydberg atoms in strong fields are presented

  20. Scalar strong interaction hadron theory

    CERN Document Server

    Hoh, Fang Chao


    The scalar strong interaction hadron theory, SSI, is a first principles' and nonlocal theory at quantum mechanical level that provides an alternative to low energy QCD and Higgs related part of the standard model. The quark-quark interaction is scalar rather than color-vectorial. A set of equations of motion for mesons and another set for baryons have been constructed. This book provides an account of the present state of a theory supposedly still at its early stage of development. This work will facilitate researchers interested in entering into this field and serve as a basis for possible future development of this theory.

  1. Strong Plate, Weak Slab Dichotomy (United States)

    Petersen, R. I.; Stegman, D. R.; Tackley, P.


    Models of mantle convection on Earth produce styles of convection that are not observed on Earth.Moreover non-Earth-like modes, such as two-sided downwellings, are the de facto mode of convection in such models.To recreate Earth style subduction, i.e. one-sided asymmetric recycling of the lithosphere, proper treatment of the plates and plate interface are required. Previous work has identified several model features that promote subduction. A free surface or pseudo-free surface and a layer of material with a relatively low strength material (weak crust) allow downgoing plates to bend and slide past overriding without creating undue stress at the plate interface. (Crameri, et al. 2012, GRL)A low viscosity mantle wedge, possibly a result of slab dehydration, decouples the plates in the system. (Gerya et al. 2007, Geo)Plates must be composed of material which, in the case of the overriding plate, are is strong enough to resist bending stresses imposed by the subducting plate and yet, as in the case of the subducting plate, be weak enough to bend and subduct when pulled by the already subducted slab. (Petersen et al. 2015, PEPI) Though strong surface plates are required for subduction such plates may present a problem when they encounter the lower mantle.As the subducting slab approaches the higher viscosity, lower mantle stresses are imposed on the tip.Strong slabs transmit this stress to the surface.There the stress field at the plate interface is modified and potentially modifies the style of convection. In addition to modifying the stress at the plate interface, the strength of the slab affects the morphology of the slab at the base of the upper mantle. (Stegman, et al 2010, Tectonophysics)Slabs that maintain a sufficient portion of their strength after being bent require high stresses to unbend or otherwise change their shape.On the other hand slabs that are weakened though the bending process are more amenable to changes in morphology. We present the results of

  2. Application conditions for ester cured alkaline phenolic resin sand

    Directory of Open Access Journals (Sweden)

    Ren-he Huang


    Full Text Available Five organic esters with different curing speeds: propylene carbonate (i.e. high-speed ester A; 1, 4-butyrolactone; glycerol triacetate (i.e. medium-speed ester B; glycerol diacetate; dibasic ester (DBE (i.e. low-speed ester C, were chosen to react with alkaline phenolic resin to analyze the application conditions of ester cured alkaline phenolic resin. The relationships between the curing performances of the resin (including pH value, gel pH value, gel time of resin solution, heat release rate of the curing reaction and tensile strength of the resin sand and the amount of added organic ester and curing temperature were investigated. The results indicated the following: (1 The optimal added amount of organic ester should be 25wt.%-30wt.% of alkaline phenolic resin and it must be above 20wt.%-50 wt.% of the organic ester hydrolysis amount. (2 High-speed ester A (propylene carbonate has a higher curing speed than 1, 4-butyrolactone, and they were both used as high-speed esters. Glycerol diacetate is not a high-speed ester in alkaline phenolic resin although it was used as a high-speed ester in ester cured sodium silicate sand; glycerol diacetate and glycerol triacetate can be used as medium-speed esters in alkaline phenolic resin. (3 High-speed ester A, medium-speed ester B (glycerol triacetate and low-speed ester C (dibasic ester, i.e., DBE should be used below 15 ìC, 35 ìC and 50 ìC, respectively. High-speed ester A or low-speed ester C should not be used alone but mixed with medium-speed ester B to improve the strength of the resin sand. (4 There should be a suitable solid content (generally 45wt.%-65wt.% of resin, alkali content (generally 10wt.%-15wt.% of resin and viscosity of alkaline phenolic resin (generally 50-300 mPa≤s in the preparation of alkaline phenolic resin. Finally, the technique conditions of alkaline phenolic resin preparation and the application principles of organic ester were discussed.

  3. The mechanism of radiolysis of alkaline-earth nitrates (United States)

    Anan'ev, V.; Kriger, L.; Miklin, M.


    The formation of peroxynitrite and nitrite in crystalline alkaline-earth nitrates under γ-irradiation at 310 K by optical reflectance spectroscopy has been studied. The radiolysis of Sr(NO3)2 and Ba(NO3)2 results in nitrite and peroxynitrite, Mg(NO3)2·6H2O and Ca(NO3)2·4H2O - nitrite. The mechanism for nitrite and peroxynitrite formation under γ-irradiation of crystalline alkaline-earth nitrates has been discussed.

  4. Spectrum Estimation of Density Operators with Alkaline-Earth Atoms (United States)

    Beverland, Michael E.; Haah, Jeongwan; Alagic, Gorjan; Campbell, Gretchen K.; Rey, Ana Maria; Gorshkov, Alexey V.


    We show that Ramsey spectroscopy of fermionic alkaline-earth atoms in a square-well trap provides an efficient and accurate estimate for the eigenspectrum of a density matrix whose n copies are stored in the nuclear spins of n such atoms. This spectrum estimation is enabled by the high symmetry of the interaction Hamiltonian, dictated, in turn, by the decoupling of the nuclear spin from the electrons and by the shape of the square-well trap. Practical performance of this procedure and its potential applications to quantum computing and time keeping with alkaline-earth atoms are discussed.

  5. Exchange potentials of phosphorus between sediments and water coupled to alkaline phosphatase activity and environmental factors in an oligo-mesotrophic reservoir. (United States)

    Mhamdi, Badre Alaoui; Azzouzi, Assia; Elloumi, Jannet; Ayadi, Habib; Mhamdi, Mohammed Alaoui; Aleya, Lotfi


    We investigated the exchange potentials of phosphates at the water-sediment interface together with in situ benthic-chamber fractionated alkaline phosphatase activity and bacteria estimates during September and October 1998 at two stations: station 1, which received immediately the urban inputs from the Taounate city, and station 2, located in the centre of the Sahela reservoir (Morocco). The results showed that low oxygenation enhanced both the bacterial abundance and the alkaline phosphatase activity. Size-fractionated (0.65-100 microm) bacteria attached to dead organic matter together with algae and zooplankton contributed strongly (78%) to the total alkaline phosphatase synthesis in the two sampled stations, suggesting that attachment to organic particles stimulated phosphatase activities. The appearance of anoxic conditions and the decrease of pH supported the dissolution of particulate phosphorus and the release of soluble reactive phosphorus. This latter, together with persisting discharges of organic matter, sewage, and olive mill waste will exacerbate the eutrophication of the reservoir.

  6. EDITORIAL: Strongly correlated electron systems Strongly correlated electron systems (United States)

    Ronning, Filip; Batista, Cristian


    Strongly correlated electrons is an exciting and diverse field in condensed matter physics. This special issue aims to capture some of that excitement and recent developments in the field. Given that this issue was inspired by the 2010 International Conference on Strongly Correlated Electron Systems (SCES 2010), we briefly give some history in order to place this issue in context. The 2010 International Conference on Strongly Correlated Electron Systems was held in Santa Fe, New Mexico, a reunion of sorts from the 1989 International Conference on the Physics of Highly Correlated Electron Systems that also convened in Santa Fe. SCES 2010—co-chaired by John Sarrao and Joe Thompson—followed the tradition of earlier conferences, in this century, hosted by Buzios (2008), Houston (2007), Vienna (2005), Karlsruhe (2004), Krakow (2002) and Ann Arbor (2001). Every three years since 1997, SCES has joined the International Conference on Magnetism (ICM), held in Recife (2000), Rome (2003), Kyoto (2006) and Karlsruhe (2009). Like its predecessors, SCES 2010 topics included strongly correlated f- and d-electron systems, heavy-fermion behaviors, quantum-phase transitions, non-Fermi liquid phenomena, unconventional superconductivity, and emergent states that arise from electronic correlations. Recent developments from studies of quantum magnetism and cold atoms complemented the traditional subjects and were included in SCES 2010. 2010 celebrated the 400th anniversary of Santa Fe as well as the birth of astronomy. So what's the connection to SCES? The Dutch invention of the first practical telescope and its use by Galileo in 1610 and subsequent years overturned dogma that the sun revolved about the earth. This revolutionary, and at the time heretical, conclusion required innovative combinations of new instrumentation, observation and mathematics. These same combinations are just as important 400 years later and are the foundation of scientific discoveries that were discussed

  7. Physics of Strongly Coupled Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Kraeft, Wolf-Dietrich [Universitat Rostock (Germany)


    Strongly coupled plasmas (or non-ideal plasmas) are multi-component charged many-particle systems, in which the mean value of the potential energy of the system is of the same order as or even higher than the mean value of the kinetic energy. The constituents are electrons, ions, atoms and molecules. Dusty (or complex) plasmas contain still mesoscopic (multiply charged) particles. In such systems, the effects of strong coupling (non-ideality) lead to considerable deviations of physical properties from the corresponding properties of ideal plasmas, i.e., of plasmas in which the mean kinetic energy is essentially larger than the mean potential energy. For instance, bound state energies become density dependent and vanish at higher densities (Mott effect) due to the interaction of the pair with the surrounding particles. Non-ideal plasmas are of interest both for general scientific reasons (including, for example, astrophysical questions), and for technical applications such as inertially confined fusion. In spite of great efforts both experimentally and theoretically, satisfactory information on the physical properties of strongly coupled plasmas is not at hand for any temperature and density. For example, the theoretical description of non-ideal plasmas is possible only at low densities/high temperatures and at extremely high densities (high degeneracy). For intermediate degeneracy, however, numerical experiments have to fill the gap. Experiments are difficult in the region of 'warm dense matter'. The monograph tries to present the state of the art concerning both theoretical and experimental attempts. It mainly includes results of the work performed in famous Russian laboratories in recent decades. After outlining basic concepts (chapter 1), the generation of plasmas is considered (chapter 2, chapter 3). Questions of partial (chapter 4) and full ionization (chapter 5) are discussed including Mott transition and Wigner crystallization. Electrical and

  8. Strongly coupled dust coulomb clusters

    International Nuclear Information System (INIS)

    Juan Wentau; Lai Yingju; Chen Mingheng; I Lin


    The structures and motions of quasi-2-dimensional strongly coupled dust Coulomb clusters with particle number N from few to hundreds in a cylindrical rf plasma trap are studied and compared with the results from the molecular dynamic simulation using more ideal models. Shell structures with periodic packing in different shells and intershell rotational motion dominated excitations are observed at small N. As N increases, the boundary has less effect, the system recovers to the triangular lattice with isotropic vortex type cooperative excitations similar to an infinite N system except the outer shell region. The above generic behaviors are mainly determined by the system symmetry and agree with the simulation results. The detailed interaction form causes minor effect such as the fine structure of packing

  9. Probability densities in strong turbulence (United States)

    Yakhot, Victor


    In this work we, using Mellin’s transform combined with the Gaussian large-scale boundary condition, calculate probability densities (PDFs) of velocity increments P(δu,r), velocity derivatives P(u,r) and the PDF of the fluctuating dissipation scales Q(η,Re), where Re is the large-scale Reynolds number. The resulting expressions strongly deviate from the Log-normal PDF P(δu,r) often quoted in the literature. It is shown that the probability density of the small-scale velocity fluctuations includes information about the large (integral) scale dynamics which is responsible for the deviation of P(δu,r) from P(δu,r). An expression for the function D(h) of the multifractal theory, free from spurious logarithms recently discussed in [U. Frisch, M. Martins Afonso, A. Mazzino, V. Yakhot, J. Fluid Mech. 542 (2005) 97] is also obtained.

  10. The rheological evolution of alkaline Vesuvius magmas and comparison with alkaline series from the Phlegrean Fields, Etna, Stromboli and Teide (United States)

    Giordano, D.; Ardia, P.; Romano, C.; Dingwell, D. B.; Di Muro, A.; Schmidt, M. W.; Mangiacapra, A.; Hess, K.-U.


    Somma-Vesuvius is considered one of the highest-risk volcanic systems in the world due to its high population density and record of highly destructive explosive activity. Eruptive style at Vesuvius varies greatly, alternating between effusive and explosive activities, and is likely strongly controlled by the evolution of the physical and chemical properties of the magma. Nevertheless, with the exception of the 1631 eruption, the rheological properties of Vesuvius magmas remain largely unconstrained. Here, we investigate the Newtonian shear viscosity ( η) of dry and hydrous melts from the Mercato (plinian) and 1906 (violent strombolian) eruptions. These eruptions differ in size, eruptive style and magma chemistry (from phonolite to phono-tephrite). To evaluate the dry liquid viscosity variation covered by the eruptive products of the recent activity at Vesuvius, we measured the melt viscosities of bulk rock compositions and, for highly crystalline samples, of the separated groundmasses of tephras from the Pollena and 1906 eruptions. Hydrated samples with up to 4.24 wt% dissolved water were synthesised in a piston cylinder apparatus at confining pressure up to 10 kbar. The dry high temperature and the dry and hydrous low-temperature viscosities were obtained by combining the concentric cylinder and micropenetration techniques. The measured viscosities were parameterized by a modified Vogel-Fulcher-Tammann equation, accounting for the effect of water content, and were compared with previous measurements and models. At magmatic temperatures, the viscosities of Mercato samples are about four orders of magnitude higher than that of the least viscous investigated products from the 1906 eruption. Complex numerical models to forecast eruptive scenarios and their environmental impact are extremely sensitive to the accuracy of the input parameters and constitutive equations of magma properties. As a consequence, the numerical expressions obtained here are of particular

  11. Recovering lead from cathode ray tube funnel glass by mechano-chemical extraction in alkaline solution. (United States)

    Zhang, Chenglong; Wang, Jingwei; Bai, Jianfeng; Guan, Jie; Wu, Wenjie; Guo, Cuixiang


    This study evaluates the efficiency of lead (Pb) extraction from cathode ray tube (CRT) funnel glass in strongly alkaline solution using mechanical activation in a ball mill as the chemical breakage and defects formed in the inner structures will contribute to the easy dissolution of the activated Pb glass. The combination of mechanical activation and a chemical leaching process in a single operation (mechano-chemical leaching) is more effective than the mechanical activation and subsequent chemical leaching. More than 97% of Pb in the CRT funnel glass can be extracted with a stirring ball mill leaching process in 5 M sodium hydroxide at 70°C. The diameter of the stainless steel balls as the activation medium is 5 mm; the mass ratio of ball to raw materials is 25:1. Pb powder with a purity of 97% can be obtained by electrowinning from the leaching solution. The Pb-depleted solution can be recycled into the leaching step. After Pb is removed, the solid leaching residues can be used for preparation of foam glass. Thus, a novel hydrometallurgical process for recovering Pb from CRT funnel glass in alkaline solution is proposed.

  12. Screening Brazilian Macrophomina phaseolina isolates for alkaline lipases and other extracellular hydrolases. (United States)

    Schinke, Claudia; Germani, José C


    Macrophomina phaseolina, phylum Ascomycota, is a phytopathogenic fungus distributed worldwide in hot dry areas. There are few studies on its secreted lipases and none on its colony radial growth rate, an indicator of fungal ability to use nutrients for growth, on media other than potato-dextrose agar. In this study, 13 M. phaseolina isolates collected in different Brazilian regions were screened for fast-growth and the production of hydrolases of industrial interest, especially alkaline lipases. Hydrolase detection and growth rate determination were done on citric pectin, gelatin, casein, soluble starch, and olive oil as substrates. Ten isolates were found to be active on all substrates tested. The most commonly detected enzymes were pectinases, amylases, and lipases. The growth rate on pectin was significantly higher (P oil was followed for 4 days by measuring the activity in the cultivation broth. The specific lipolytic activity of isolate PEL was significantly higher at 96 h (130 mU mg protein(-1)). The broth was active at 37 °C, pH 8, indicating the potential utility of the lipases of this isolate in mild alkaline detergents. There was a strong and positive correlation (0.86) between radial growth rate and specific lipolytic activity.

  13. Actinides in Hanford Tank Waste Simulants: Chemistry of Selected Species in Oxidizing Alkaline Solutions

    International Nuclear Information System (INIS)

    Nash, Kenneth L.; Laszak, Ivan; Borkowski, Marian; Hancock, Melissa; Rao, Linfeng; Reed, Wendy


    To enhance removal of selected troublesome nonradioactive matrix elements (P, Cr, Al, S) from the sludges in radioactive waste tanks at the Hanford site, various chemical washing procedures have been evaluated. It is intended that leaching should leave the actinides in the residual sludge phase for direct vitrification. Oxidative treatment with strongly alkaline solutions has emerged as the best approach to accomplishing this feat. However, because the most important actinide ions in the sludge can exist in multiple oxidation states, it is conceivable that changes in actinide oxidation state speciation could interfere with hopes and plans for actinide insolubility. In this presentation, we discuss both the impact of oxidative alkaline leachants on actinide oxidation state speciation and the chemistry of oxidized actinide species in the solution phase. Actinide oxidation does occur during leaching, but the solubility behavior is complex. Mixed ligand complexes may dominate solution phase speciation of actinides under some circumstances. This work was supported by the U.S. Department of Energy, Offices of Science and Waste Management, Environmental Management Science Program under Contract DEAC03- 76SF0098 at Lawrence Berkeley National Laboratory and Contract W-31-109- ENG-38 at Argonne National Laboratory

  14. Alkalinity and hardness: Critical but elusive concepts in aquaculture (United States)

    Total alkalinity and total hardness are familiar variables to those involved in aquatic animal production. Aquaculturists – both scientists and practitioners alike – tend to have some understanding of the two variables and of methods for adjusting their concentrations. The chemistry and the biolog...

  15. Isolation of alkaline protease from Bacillus subtilis AKRS3

    African Journals Online (AJOL)



    Aug 28, 2012 ... This research study was mainly focused on phenotypic, biochemical characterization, 16s rRNA sequence based species level identification of isolate and determination of the higher production of alkaline protease through optimization study (carbon, nitrogen, incubation period, temperature, pH and.

  16. Development of nano indium tin oxide (ITO) grains by alkaline ...

    Indian Academy of Sciences (India)


    Bull. Mater. Sci., Vol. 25, No. 6, November 2002, pp. 505–507. © Indian Academy of Sciences. 505. Development of nano indium tin oxide (ITO) grains by alkaline hydrolysis of In(III) and Sn(IV) salts. NIMAI CHAND ... et al 1996; Yanagisawa and Udawatte 2000; Denoy and. Pradeep 1997) with low Sn content (In : Sn ≥ 90 ...

  17. Production of alkaline proteases by alkalophilic Bacillus subtilis ...

    African Journals Online (AJOL)

    Tuoyo Aghomotsegin


    Nov 23, 2016 ... detergent industries (Moon and Parulekar, 1991). Proteases of commercial importance are produced from microbial, animal and plant sources (Patel, 1985). Almost all living organisms can produce alkaline protease at 32 to 45°C and pH 8 to 9 (Akcan and Uyar, 2011). Microbial proteases are produced ...

  18. Secondary Structures Associated With Alkaline Transition of Horse ...

    African Journals Online (AJOL)


    ABSTRACT: The spectra of amide I region (1700-1600cm-1) of horse heart ferricytochrome c at. 20oC are reported at low ionic strength at of pH values between 7.0 and 11.5 encompassing the alkaline transition. The mid-infrared spectra can probe the protein secondary structures. The Fourier transform infrared ...

  19. Synthesis of monomeric and polymeric alkali and alkaline earth ...

    Indian Academy of Sciences (India)

    5, September 2014, pp. 1463–1475. c Indian Academy of Sciences. Synthesis of monomeric and polymeric alkali and alkaline earth metal complexes using a phosphinoselenoic amide ligand in metal coordination sphere. JAYEETA BHATTACHARJEE, RAVI K KOTTALANKA, HARINATH ADIMULAM and TARUN K PANDA.

  20. Activation of Rat Intestinal Alkaline Phosphatase by Taurine May be ...

    African Journals Online (AJOL)

    Dr. K.J. Umar

    targets for the gut mucosal defense factor intestinal alkaline phosphatase. American Journal of. Physiology-Gastrointestinal and Liver Physiology,. 299(2): G467–G475. Corrigan, J.J., Ray, W.L and May, N. (1968). Changes in the blood coagulation system associated with septicemia. The New England Journal of Medicine,.

  1. Spectroscopic characterization of manganese-doped alkaline earth

    Indian Academy of Sciences (India)

    The intensity and frequency variations for the characteristic phosphate group vibrations have been correlated with the changes of the structural units present in these glasses. Depolymerization of the phosphate chains in all the glasses is observed with replacement of alkaline earth content by spectroscopic studies.

  2. Dephosphorylation of endotoxin by alkaline phosphatase in vivo

    NARCIS (Netherlands)

    Poelstra, Klaas; Bakker, W.W; Klok, P.A; Kamps, J.AAM; Hardonk, M.J; Meijer, D.K F


    Natural substrates for alkaline phosphatase (AP) are at present not identified despite extensive investigations. Difficulties in imagining a possible physiological function involve its extremely high pH optimum for the usual exogenous substrates and its localization as an ecto-enzyme. As endotoxin

  3. Optical properties of alkaline earth borate glasses | Rao ...

    African Journals Online (AJOL)

    Borate glasses containing fixed concentrations of heavy metal oxides (MO= ZnO, PbO, TeO2, Bi2O3) and alkaline earth oxides (R= Mg, Ca, Sr, Ba) are prepared by melt quenching technique. The optical band gap values are estimated from the optical absorption spectra using absorption spectrum fitting (ASF) method.

  4. Lipid accumulation and alkaline phosphatase activity in human ...

    African Journals Online (AJOL)

    Background: Alkaline phosphatase (ALP) controls intracellular lipid accumulation in human preadipocytes, but it is not known whether ALP is expressed in all body fat depots, or whether it has a similar role at all sites. Design: Cross-sectional. Setting and subjects: Subjects undergoing breast reduction and abdominal fat ...

  5. Secondary Structures Associated With Alkaline Transition of Horse ...

    African Journals Online (AJOL)


    Wasagu et al.; Secondary Structures Associated With Alkaline Transition of Horse Heart Ferricytochrome C: An FTIR Study. 251 above mentioned enhancement techniques. In contrast with single band observed in the primary spectrum, second derivative in the amide I region (1700 and 1600 cm-1), was characterized by ...

  6. Spectroscopic characterization of manganese-doped alkaline earth ...

    Indian Academy of Sciences (India)

    Alkaline earth lead zinc phosphate glasses doped with Mn(II) are characterized by spectroscopic techniques like X-ray diffraction (XRD), UV–visible, differential scanning calorimetry (DSC), electron paramagnetic resonance (EPR), Fourier transform infrared (FTIR) and Raman. Optical absorption spectrum exhibits four ...

  7. Structural variations in layered alkaline earth metal cyclohexyl ...

    Indian Academy of Sciences (India)


    because of the entrance of the guest molecules between the layers, there will be a change in the interlayer distance (Alberti 1978). Although M(IV) organo-phos- phonates are well documented, the chemistry of M(II) organophosphonates especially the alkaline earth metal organophosphonates has been explored marginally ...

  8. Synthesis and infrared spectra of alkaline earth metal carbonates ...

    Indian Academy of Sciences (India)


    investigations deal with the synthesis and characteriza- tion of complexes of urea with transition metals (Penland et al 1957; Schafer and Curran 1966; Barbier and Hugel. 1974, 1977; Srivastava and Aravindakshan 1983). How- ever, studies on the nature of the reaction of urea with alkaline earth metals are very rare and ...

  9. Isolation and screening of alkaline protease producing bacteria and ...

    African Journals Online (AJOL)

    Soil samples from different habitats including tanneries, soap industries, garden soil and soil compost were screened for the presence of alkalophilic Bacillus isolates capable of producing alkaline protease in large quantities. One hundred and eighteen (118) isolates were found having proteolytic activity on skim milk agar ...

  10. Chromatographic separation of alkaline phosphatase from dental enamel

    DEFF Research Database (Denmark)

    Moe, D; Kirkeby, S; Salling, E


    Alkaline phosphatase (AP) was prepared from partly mineralized bovine enamel by extraction in phosphate buffer, centrifugation and various chromatographic techniques. Chromatofocusing showed that the enamel enzyme possessed five isoelectric points at the acid pH level ranging from pH 5.7 to pH 4...

  11. Isolation of alkaline protease from Bacillus subtilis AKRS3 ...

    African Journals Online (AJOL)

    This research study was mainly focused on phenotypic, biochemical characterization, 16s rRNA sequence based species level identification of isolate and determination of the higher production of alkaline protease through optimization study (carbon, nitrogen, incubation period, temperature, pH and sodium chloride ...

  12. Production of Thermostable Alkaline Protease from Streptomyces sp ...

    African Journals Online (AJOL)

    Bacterial extracellular alkaline proteases have been found to have broad spectrum industrial applications because of their stability characteristics among the bacteria. The Actinomyces are of enormous importance as they can be recovered easier than other bacteria after fermentation. Thus, the study was aimed at sourcing ...

  13. Kinetic Studies of Alkaline Phosphatase from the Liver of Agama ...

    African Journals Online (AJOL)

    Kinetic studies were carried out on alkaline phosphatase (ALP) extracted from the liver of Agama agama lizard. Incubation of ALP extract with para – nitrophenyl phosphate formed the basis for the determination of enzyme activity. Spectrophotometric method was used to assay the enzyme, and the kinetic constants: ...

  14. Alkaline pretreatment of Mexican pine residues for bioethanol ...

    African Journals Online (AJOL)

    Alkaline pretreatment of Mexican pine residues for bioethanol production. Claudia Elena Soto Alvarez, Javier López Miranda, Gustavo Pérez Verdín, Mario A. Rodríguez Pérez, Isaías Chairez Hernández ...

  15. Biochemical Investigation on the activities of Acid and Alkaline ...

    African Journals Online (AJOL)

    The activities of acid phosphatase and alkaline phosphatase were investigated in two varieties of ripening Carica papaya fruit; Oblong-shaped variety which is also known as 'Agric pawpaw' and Pear-shaped variety which is also known as 'Local pawpaw'. Acid phosphatase activity decreased significantly (p < 0.01) ...

  16. Optimization of alkaline α-amylase production by thermophilic ...

    African Journals Online (AJOL)

    Background: Starch‐degrading amylase enzyme is important in biotechnological applications as food, fermentation, textile, paper and pharmaceutical purposes. The aim of current study to isolate alkaline thermostable α-amylase bacteria and then study the composition of medium and culture conditions to optimize cells ...

  17. Secondary Structures Associated With Alkaline Transition of Horse ...

    African Journals Online (AJOL)

    The spectra of amide I region (1700-1600cm-1) of horse heart ferricytochrome c at 20oC are reported at low ionic strength at of pH values between 7.0 and 11.5 encompassing the alkaline transition. The mid-infrared spectra can probe the protein secondary structures. The Fourier transform infrared spectroscopic technique ...

  18. Regulatory effect of divalent cations on rat liver alkaline ...

    African Journals Online (AJOL)

    The concentration-dependent stimulation of rat liver alkaline phosphatase (ALP) catalyzed hydrolysis of para- nitrophenylphosphate (pNPP) was studied. ALP displayed some activity even in the absence of exogenous Mg2+. Kinetic analyses show that activation by Mg2+ is exerted at the Vmax level without necessarily ...

  19. Alkaline Protease from Bacillus firmus 7728 | Rao | African Journal ...

    African Journals Online (AJOL)

    Extracellular alkaline protease producing Bacillus firmus MTCC 7728 was isolated from the soil samples taken from the leather factories in Nacharam industrial area, Hyderabad. Maximum activity was found after 48 h of fermentation. Optimum pH and temperature for maximum enzyme activity were 9 and 40°C, respectively.

  20. Histochemical Study Of The Effect Of Ethanol On Alkaline ...

    African Journals Online (AJOL)

    An experimental investigation of the mechanisms of action of this toxic agent was conducted in the femoral bones of the foetal Wistar rat by the histochemical assessment of the activity of alkaline phosphatase, an enzyme present within the osteoblasts and actively involved in the mineral deposition in bones during ...

  1. Electrochemical oxidation and detection of sodium urate in alkaline ...

    African Journals Online (AJOL)

    Electrochemical behaviour of copper oxides electrode in the presence of sodium urate was investigated. The correlation between the anodic oxidation and the amperometric detection of sodium urate in the alkaline medium on copper oxides electrode was analysed by cyclic voltammetry (CV) and electrochemical ...

  2. Production of thermostable and organic solvent-tolerant alkaline ...

    African Journals Online (AJOL)

    An alkaliphilic bacterium producing organic solvent-tolerant and thermostable alkaline protease was isolated from poultry litter site and identified as Bacillus coagulans PSB-07. Protease production under different submerged fermentation conditions were investigated with the aim of optimizing yield of enzyme. B. coagulans ...

  3. Effect of alkaline treated soybean meal on the performance, protein ...

    African Journals Online (AJOL)

    An experiment was conducted to evaluate the effect of alkaline treated soybean seeds on the performance, protein and energy efficiency of starter broilers. Soybean seeds were divided into 4 batches. The first batch was autoclaved at 100°C and the other batches soaked in aqueous solution of 3% concentration of sodium ...

  4. Response to alkaline stress by root canal bacteria in biofilms. (United States)

    Chávez de Paz, L E; Bergenholtz, G; Dahlén, G; Svensäter, G


    To determine whether bacteria isolated from infected root canals survive alkaline shifts better in biofilms than in planktonic cultures. Clinical isolates of Enterococcus faecalis, Lactobacillus paracasei, Olsenella uli, Streptococcus anginosus, S. gordonii, S. oralis and Fusobacterium nucleatum in biofilm and planktonic cultures were stressed at pH 10.5 for 4 h, and cell viability determined using the fluorescent staining LIVE/DEAD BacLight bacterial viability kit. In addition, proteins released into extracellular culture fluids were identified by Western blotting. Enterococcus faecalis, L. paracasei, O. uli and S. gordonii survived in high numbers in both planktonic cultures and in biofilms after alkaline challenge. S. anginosus, S. oralis and F. nucleatum showed increased viability in biofilms compared with planktonic cultures. Alkaline exposure caused all planktonic cultures to aggregate into clusters and resulted in a greater extrusion of cellular proteins compared with cells in biofilms. Increased levels of DnaK, HPr and fructose-1,6-bisphosphate aldolase were observed in culture fluids, especially amongst streptococci. In general, bacteria isolated from infected roots canals resisted alkaline stress better in biofilms than in planktonic cultures, however, planktonic cells appeared to use aggregation and the extracellular transport of specific proteins as survival mechanisms.

  5. Alkalinity production in intertidal sands intensified by lugworm bioirrigation

    NARCIS (Netherlands)

    Rao, A.M.F.; Malkin, S.Y.; Montserrat, F; Meysman, F.J.R.


    Porewater profiles and sediment-water fluxes of oxygen, nutrients, pH, calcium, alkalinity, and sulfide were measured in intertidal sandflat sediments from the Oosterschelde mesotidal lagoon (The Netherlands). The influence of bioturbation and bioirrigation by the deep-burrowing polychaete

  6. Field screening of cowpea cultivars for alkaline soil tolerance (United States)

    Cowpea or Southernpea [Vigna unguiculata (L.) Walp.] is an important legume crop used as a feed for livestock, as a green vegetable and for consumption of its dry beans which provide 22-25% protein. The crop is very sensitive to alkaline soil conditions. When grown at soil pH of 7.5 or higher, cowp...

  7. Yield performance of cowpea genotypes grown in alkaline soils (United States)

    Cowpea or Southernpea [Vigna unguiculata (L.) Walp.] is an important legume crop used as a feed for livestock, as a green vegetable and for consumption of its dry beans which provide 22-25% protein. The crop is very sensitive to alkaline soil conditions. When grown at soil pH of 7.5 or higher, cowp...

  8. Normal serum alkaline phosphatase in the presence of extensive ...

    African Journals Online (AJOL)

    Normal serum alkaline phosphatase in this patient in the presence of extensive skeletal metastases may be due to the combination of the following factors: relative hypogonadism, osteoporosis, low serum zinc and magnesium. This case report may provide a possible explanation for the observation that about 10% of men ...

  9. Stability and selectivity of alkaline proteases in hydrophilic solvents

    DEFF Research Database (Denmark)

    Pedersen, Lars Haastrup; Ritthitham, Sinthuwat; Pleissner, Daniel


    Hydrophilic, organic solvents can be used as co-solvents with water to produce one phase systems sustaining optimal mass transfer of substrates and products of mixed polarity in biocatalysed processes. At concentrations below 50 % hydrophilic solvents can even have a stabilising effect on alkalin...


    NARCIS (Netherlands)

    Schippers, Marlies; Post, E.; Cetintas, A.; Reker-Smit, C.; Beljaars, L.; Poelstra, K.

    Background and Aim: Serum alkaline phosphatase (AP) levels serve as a marker for many liver diseases. Recent studies indicate that AP may act as a protective enzyme by dephosphorylation of LPS because dephosphorylation blocks toxicity of this product. Gut-derived LPS is known to aggravate liver

  11. based anion exchange membrane for alkaline polymer electrolyte

    Indian Academy of Sciences (India)


    Abstract. Hydroxyl ion (OH–) conducting anion exchange membranes based on modified poly (phenylene oxide) are fabricated for their application in alkaline polymer electrolyte fuel cells (APEFCs). In the present study, chloromethylation of poly(phenylene oxide) (PPO) is performed by aryl substitution rather than benzyl.

  12. Transcriptome analysis of Enterococcus faecalis in response to alkaline stress. (United States)

    Ran, Shujun; Liu, Bin; Jiang, Wei; Sun, Zhe; Liang, Jingping


    Enterococcus faecalis is the most commonly isolated species from endodontic failure root canals; its persistence in treated root canals has been attributed to its ability to resist high pH stress. The goal of this study was to characterize the E. faecalis transcriptome and to identify candidate genes for response and resistance to alkaline stress using Illumina HiSeq 2000 sequencing. We found that E. faecalis could survive and form biofilms in a pH 10 environment and that alkaline stress had a great impact on the transcription of many genes in the E. faecalis genome. The transcriptome sequencing results revealed that 613 genes were differentially expressed (DEGs) for E. faecalis grown in pH 10 medium; 211 genes were found to be differentially up-regulated and 402 genes differentially down-regulated. Many of the down-regulated genes found are involved in cell energy production and metabolism and carbohydrate and amino acid metabolism, and the up-regulated genes are mostly related to nucleotide transport and metabolism. The results presented here reveal that cultivation of E. faecalis in alkaline stress has a profound impact on its transcriptome. The observed regulation of genes and pathways revealed that E. faecalis reduced its carbohydrate and amino acid metabolism and increased nucleotide synthesis to adapt and grow in alkaline stress. A number of the regulated genes may be useful candidates for the development of new therapeutic approaches for the treatment of E. faecalis infections.

  13. Soil salinity and alkalinity in the Great Konya Basin, Turkey

    NARCIS (Netherlands)

    Driessen, P.M.


    In the summers of 1964 to 1968 a study was made of soil salinity and alkalinity in the Great Konya Basin, under the auspices of the Konya Project, a research and training programme of the Department of Tropical Soil Science of the Agricultural University, Wageningen.

    The Great

  14. Extracellular Alkalinization as a Defense Response in Potato Cells. (United States)

    Moroz, Natalia; Fritch, Karen R; Marcec, Matthew J; Tripathi, Diwaker; Smertenko, Andrei; Tanaka, Kiwamu


    A quantitative and robust bioassay to assess plant defense response is important for studies of disease resistance and also for the early identification of disease during pre- or non-symptomatic phases. An increase in extracellular pH is known to be an early defense response in plants. In this study, we demonstrate extracellular alkalinization as a defense response in potatoes. Using potato suspension cell cultures, we observed an alkalinization response against various pathogen- and plant-derived elicitors in a dose- and time-dependent manner. We also assessed the defense response against a variety of potato pathogens, such as protists ( Phytophthora infestans and Spongospora subterranea ) and fungi ( Verticillium dahliae and Colletotrichum coccodes ). Our results show that extracellular pH increases within 30 min in proportion to the number of pathogen spores added. Consistently with the alkalinization effect, the higher transcription level of several defense-related genes and production of reactive oxygen species was observed. Our results demonstrate that the alkalinization response is an effective marker to study early stages of defense response in potatoes.

  15. On the variation of alkalinity during phytoplankton photosynthesis

    Directory of Open Access Journals (Sweden)


    Full Text Available The alkalinity of the organic constituents of marine phytoplankton and their participation in the total alkalinity (TA change of seawater during photosynthesis are carefully assessed. Quantification of the contribution of phytoplankton chlorophyll, proteins and phosphorus compounds to the hydrogen ion balance of seawater in terms of total inorganic nitrogen (∆[NT] = ∆[NH4 +] + ∆[N2] + ∆[NO2 –] + ∆[NO3 –] and total inorganic phosphorus (∆[PT] changes during photosynthesis yielded that the organic components of marine phytoplankton are alkaline by –0.06 × ∆[NT] – 0.49 × ∆[PT], and that the potential total alkalinity (TAP during photosynthesis is TAP = TA – [NH4 –] + 0.93 × [NO2 –] + [NO3 –] + 0.08 × [NT] + 0.23 × [PT] for unfiltered seawater samples and TAP = TA – [NH4 –] + 0.93 × [NO2 –] + [NO3 –] + 0.02 × [NT] + 0.26 × [PT] for filtered seawater samples. These equations correct the traditionally used expression TAP = TA + [NO3 –]. The TAP anomalies are produced, in order of increasing importance, by N2 fixation, DMSP production and CaCO3 fixation.

  16. High Iridium concentration of alkaline rocks of Deccan and ...

    Indian Academy of Sciences (India)

    R. Narasimhan, Krishtel eMaging Solutions

    We report here an unusually high concentration of iridium in some alkali basalts and alkaline rocks of Deccan region having an age of about 65Ma, similar to the age of the Cretaceous-Tertiary boundary. The alkali basalts of Anjar, in the western periphery of Deccan province, have irid- ium concentration as high as 178pg/g ...

  17. Lipid accumulation and alkaline phosphatase activity in human ...

    African Journals Online (AJOL)


    Oct 3, 2012 ... Background: Alkaline phosphatase (ALP) controls intracellular lipid accumulation in human preadipocytes, but it is not known whether ALP .... glutamine, supplemented with 10% foetal bovine serum and 100 U/ml penicillin ..... by a cascade of transcription factor gene expression.34. Evidence that ALP acts ...

  18. Potentiodynamic characteristics of cadmium and silver in alkaline solutions

    International Nuclear Information System (INIS)

    Saidman, S.B.; Vilche, J.R.; Arvia, A.J.; Lopes Teijelo, M.


    The potentiodynamic and ellipsometric characteristics of cadmium and silver in alkaline solutions are studied. The phenomenology of both electrodes shows some common features which are interpreted in termo of a complex hydrated oxide anodic film structure resulting from simultaneous electrochemical and chemical reactions. The kinetics of film growth fits the predictions of nucleation and growth models. (C.L.B.) [pt

  19. Effect of alkaline hydrolysis on the quantity of extractable protein ...

    African Journals Online (AJOL)



    Nov 16, 2009 ... Key words: Prolamin, albumin, globulin, glutelin, alkaline hydrolysis. INTRODUCTION. Oil seeds are major source of vegetable proteins. The presence of toxins and antinutrients in some of them has limited their use as food and animal feed source. Such antinutrients include glucosinolate in rape seed, ...

  20. Preliminary note on the utitization of alkaline hydrogen peroxide ...

    African Journals Online (AJOL)

    The effect of alkaline hydrogen peroxide (AHp) treatment and urea supplementation on the feeding value of wheat straw was investigated in a 2x2 factorial experiment with sheep. Bales of wheat straw were dipped for a period of 24 h in an. AHP solution consisting of 1"/" hydrogen peroxide and 0,55% sodium hydroxide ...

  1. High-level expression of alkaline protease using recombinant ...

    African Journals Online (AJOL)

    The apr gene was cloned into plasmid pUB110, resulting in the recombinant plasmid pUB-apr, which was then transformed into Bacillus amyloliquefaciens CICIM B4803. The protease productivity was significantly improved in the transformants of B. amyloliquefaciens CICIM B4803. A transformant with high alkaline ...

  2. An oxidant, detergent and salt stable alkaline protease from Bacillus ...

    African Journals Online (AJOL)

    A novel soil bacterium, Bacillus cereus SIU1 was earlier isolated from non-saline, slightly alkaline soil of Eastern Uttar Pradesh, India. The isolate B. cereus SIU1 was grown in modified glucose yeast extract (modified GYE) medium at pH 9.0 and 45°C. It produced maximum protease at 20 h incubation. The enzyme was ...

  3. Kinetic studies of alkaline phosphatase extracted from rabbit ( Lepus ...

    African Journals Online (AJOL)

    Studies were carried out to ascertain some kinetic properties of alkaline phosphatase (ALP) extracted from Lepus townsendii liver. Incubation of ALP extract with 4-nitrophenylphosphate (4-NPP) formed the basis for determination of enzyme activity. Spectrophotometric method was used to assay the enzyme activity, and the ...

  4. Transcriptome Analysis of Enterococcus faecalis in Response to Alkaline Stress

    Directory of Open Access Journals (Sweden)

    Ran eshujun


    Full Text Available E. faecalis is the most commonly isolated species from endodontic failure root canals; its persistence in treated root canals has been attributed to its ability to resist high pH stress. The goal of this study was to characterize the E. faecalis transcriptome and to identify candidate genes for response and resistance to alkaline stress using Illumina HiSeq 2000 sequencing.We found that E. faecalis could survive and form biofilms in a pH 10 environment and that alkaline stress had a great impact on the transcription of many genes in the E. faecalis genome. The transcriptome sequencing results revealed that 613 genes were differentially expressed (DEGs for E. faecalis grown in pH 10 medium; 211 genes were found to be differentially up-regulated and 402 genes differentially down-regulated. Many of the down-regulated genes found are involved in cell energy production and metabolism and carbohydrate and amino acid metabolism, and the up-regulated genes are mostly related to nucleotide transport and metabolism. The results presented here reveal that cultivation of E. faecalis in alkaline stress has a profound impact on its transcriptome. The observed regulation of genes and pathways revealed that E. faecalis reduced its carbohydrate and amino acid metabolism and increased nucleotide synthesis to adapt and grow in alkaline stress. A number of the regulated genes may be useful candidates for the development of new therapeutic approaches for the treatment of E. faecalis infections.

  5. Alkalinity Analysis. Training Module (United States)

    Bonte, John L.; Davidson, Arnold C.

    This document is an instructional module package prepared in objective form for use by an instructor familiar with the acid-base titrimetric procedure for determining the hydroxide, carbonate and bicarbonate alkalinity of a water sample. Included are objectives, an instructor guide, student handouts and transparency masters. A video tape is also…

  6. Alkaline-earth metal phenylphosphonates and their intercalation chemistry

    Czech Academy of Sciences Publication Activity Database

    Melánová, Klára; Beneš, L.; Svoboda, J.; Zima, Vítězslav; Pospíšil, M.; Kovář, P.


    Roč. 47, č. 9 (2018), s. 2867-2880 ISSN 1477-9226 R&D Projects: GA ČR(CZ) GA17-10639S Institutional support: RVO:61389013 Keywords : intercalation * layered compounds * alkaline-earth metal phenylphosphonates Subject RIV: CA - Inorganic Chemistry OBOR OECD: Inorganic and nuclear chemistry Impact factor: 4.029, year: 2016

  7. Effects of Mixed Alkaline Earth Oxides in Potash Silicate Glass ...

    African Journals Online (AJOL)

    The aim of this work is to investigate the effects of mixed alkaline earth oxide in potash silicate glasses with regards to their physical properties. More recently; there has been an increase in the demand for light weight glasses which retains their physical and chemical properties for both domestic and industrial applications.

  8. High-level expression of alkaline protease using recombinant ...

    African Journals Online (AJOL)



    Feb 16, 2012 ... compared with that of wild-type B. licheniformis CICIM B5102. Key word: Alkaline protease, Bacillus amyloliquefaciens, Bacillus licheniformis. INTRODUCTION. Proteases are one of the most important industrial enzyme groups, accounting for approximately 60% of the total enzyme sales (Beg et al., 2003).

  9. Production of alkaline proteases by alkalophilic Bacillus subtilis ...

    African Journals Online (AJOL)

    Among various nitrogen sources, yeast extract was found to be the best inducer of alkaline protease. Among metal salts, KNO3 and NH4Cl were found to increase protease production. The maximum enzyme production (3600 U/ml) was observed with pomegranate peels of fermentation medium in the presence of yeast ...

  10. Kinetic characteristics of acidic and alkaline ceramidase in human epidermis

    NARCIS (Netherlands)

    Houben, E.; Uchida, Y.; Nieuwenhuizen, W.F.; Paepe, K. de; Vanhaecke, T.; Holleran, W.M.; Rogiers, V.


    It has recently become evident that at least five ceramidase (CDase) isoforms are present in human epidermis, and that specifically acidic CDase (aCDase) and alkaline CDase (alkCDase) activities increase during keratinocyte differentiation, and thus might play a pivotal role(s) in permeability


    International Nuclear Information System (INIS)

    Clark-Deaborg, David


    Highly alkaline radioactive waste tanks contain a number of transuranic species, in particular U, Np, Pu, and Am--the exact forms of which are currently unknown. Knowledge of actinide speciation under highly alkaline conditions is essential towards understanding and predicting their solubility and sorption behavior in tanks, determining whether chemical separations are needed for waste treatment, and designing separations processes. Baseline washing of tank sludges with NaOH solutions is being proposed to reduce the volume of HLW. Alkaline pretreatment of HLW will be needed to remove aluminum [as NaAl(OH) 4 ] because it significantly reduces the HLW volume; however, aluminate [Al(OH) 4 - ] enhances actinide solubility via an unknown mechanism. Thus, alkaline wash residues may require an additional treatment to remove actinides. The results of this research will determine the nature TRU (Np, Pu, Am) speciation with aluminate anions under alkaline, oxidizing tank-like conditions. Specific issues to be addressed include solubility of these actinides, speciation in aluminate-containing alkaline supernatants, the role of actinide redox states on solubility, and partitioning between supernatant and solid phases, including colloids. Studies will include thermodynamics, kinetics, spectroscopy, electrochemistry, etc. It is already known, for example, that certain high valent forms of NF and Pu are very soluble under alkaline conditions due to the formation of anionic hydroxo complexes, AnO 2 (OH) 4 2- and AnO 2 (OH) 5 3- . The presence of aluminate ions causes the actinide solubilities to increase, although the exact species have only been determined during this program. We are continuing to characterize high-valent TRU elements bound to oxo, water, OH - , under waste-like and sludge washing conditions. These conditions are in the range of 1-3 M excess hydroxide, ∼0.2 M carbonate, ∼0.5 M aluminate, for a total sodium of 2-4 mols/kg. Molecular structure-specific probes

  12. Reduction of nitrobenzene with alkaline ascorbic acid: Kinetics and pathways

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Chenju, E-mail: [Department of Environmental Engineering, National Chung Hsing University 250, Kuo-kuang Road, Taichung 402, Taiwan (China); Lin, Ya-Ting [Department of Environmental Engineering, Chung Yuan Christian University, 200 Chung Pei Road, Chung Li District, Taoyuan City 320, Taiwan (China); Shiu, Jia-Wei [Department of Environmental Engineering, National Chung Hsing University 250, Kuo-kuang Road, Taichung 402, Taiwan (China)


    Highlights: • Alkaline ascorbic acid (a.k.a. vitamin C) is capable of reductively degrading NB. • The pH above the pK{sub a2} of ascorbic acid increases reductive electron transfer to NB. • The rate equation for the reactions between NB and AA is determined. • NSB, AZOXY, and AZO are identified as intermediates and aniline as a final product. • Alkaline pH is essential for AA remediation of NB contaminated soils. - Abstract: Alkaline ascorbic acid (AA) exhibits the potential to reductively degrade nitrobenzene (NB), which is the simplest of the nitroaromatic compounds. The nitro group (NO{sub 2}{sup −}) of NB has a +III oxidation state of the N atom and tends to gain electrons. The effect of alkaline pH ranging from 9 to 13 was initially assessed and the results demonstrated that the solution pH, when approaching or above the pK{sub a2} of AA (11.79), would increase reductive electron transfer to NB. The rate equation for the reactions between NB and AA at pH 12 can be described as r = ((0.89 ± 0.11) × 10{sup −4} mM{sup 1−(a} {sup +} {sup b)} h{sup −1}) × [NB]{sup a} {sup =} {sup 1.35} {sup ±} {sup 0.10}[AA]{sup b} {sup =} {sup 0.89} {sup ±} {sup 0.01}. The GC/MS analytical method identified nitrosobenzene, azoxybenzene, and azobenzene as NB reduction intermediates, and aniline (AN) as a final product. These experimental results indicate that the alkaline AA reduction of NB to AN mainly proceeds via the direct route, consisting of a series of two-electron or four-electron transfers, and the condensation reaction plays a minor route. Preliminary evaluation of the remediation of spiked NB contaminated soils revealed that maintenance of alkaline pH and a higher water to soil ratio are essential for a successful alkaline AA application.

  13. Strong Ideal Convergence in Probabilistic Metric Spaces

    Indian Academy of Sciences (India)

    In the present paper we introduce the concepts of strongly ideal convergent sequence and strong ideal Cauchy sequence in a probabilistic metric (PM) space endowed with the strong topology, and establish some basic facts. Next, we define the strong ideal limit points and the strong ideal cluster points of a sequence in this ...

  14. Strong ideal convergence in probabilistic metric spaces

    Indian Academy of Sciences (India)

    In the present paper we introduce the concepts of strongly ideal convergent sequence and strong ideal Cauchy sequence in a probabilistic metric (PM) space endowed with the strong topology, and establish some basic facts. Next, we define the strong ideal limit points and the strong ideal cluster points of a sequence in this ...

  15. Remnants of strong tidal interactions

    International Nuclear Information System (INIS)

    Mcglynn, T.A.


    This paper examines the properties of stellar systems that have recently undergone a strong tidal shock, i.e., a shock which removes a significant fraction of the particles in the system, and where the shocked system has a much smaller mass than the producer of the tidal field. N-body calculations of King models shocked in a variety of ways are performed, and the consequences of the shocks are investigated. The results confirm the prediction of Jaffe for shocked systems. Several models are also run where the tidal forces on the system are constant, simulating a circular orbit around a primary, and the development of tidal radii under these static conditions appears to be a mild process which does not dramatically affect material that is not stripped. The tidal radii are about twice as large as classical formulas would predict. Remnant density profiles are compared with a sample of elliptical galaxies, and the implications of the results for the development of stellar populations and galaxies are considered. 38 refs

  16. John Strong - 1941-2006

    CERN Document Server


    Our friend and colleague John Strong was cruelly taken from us by a brain tumour on 31 July, a few days before his 65th birthday. John started his career and obtained his PhD in a group from Westfield College, initially working on experiments at Rutherford Appleton Laboratory (RAL). From the early 1970s onwards, however, his research was focused on experiments in CERN, with several particularly notable contributions. The Omega spectrometer adopted a system John had originally developed for experiments at RAL using vidicon cameras (a type of television camera) to record the sparks in the spark chambers. This highly automated system allowed Omega to be used in a similar way to bubble chambers. He contributed to the success of NA1 and NA7, where he became heavily involved in the electronic trigger systems. In these experiments the Westfield group joined forces with Italian colleagues to measure the form factors of the pion and the kaon, and the lifetime of some of the newly discovered charm particles. Such h...

  17. Strong seismic ground motion propagation

    International Nuclear Information System (INIS)

    Seale, S.; Archuleta, R.; Pecker, A.; Bouchon, M.; Mohammadioun, G.; Murphy, A.; Mohammadioun, B.


    At the McGee Creek, California, site, 3-component strong-motion accelerometers are located at depths of 166 m, 35 m and 0 m. The surface material is glacial moraine, to a depth of 30.5 m, overlying homfels. Accelerations were recorded from two California earthquakes: Round Valley, M L 5.8, November 23, 1984, 18:08 UTC and Chalfant Valley, M L 6.4, July 21, 1986, 14:42 UTC. By separating out the SH components of acceleration, we were able to determine the orientations of the downhole instruments. By separating out the SV component of acceleration, we were able to determine the approximate angle of incidence of the signal at 166 m. A constant phase velocity Haskell-Thomson model was applied to generate synthetic SH seismograms at the surface using the accelerations recorded at 166 m. In the frequency band 0.0 - 10.0 Hz, we compared the filtered synthetic records to the filtered surface data. The onset of the SH pulse is clearly seen, as are the reflections from the interface at 30.5 m. The synthetic record closely matches the data in amplitude and phase. The fit between the synthetic accelerogram and the data shows that the seismic amplification at the surface is a result of the contrast of the impedances (shear stiffnesses) of the near surface materials

  18. Isolation of radioactive strontium from natural samples. Separation of strontium from alkaline and alkaline earth elements by means of mixed solvent anion exchange

    International Nuclear Information System (INIS)

    Grahek, Z.; Kosutic, K.; Lulic, S.; Kvastek, K.; Eskinja, I.


    This paper presents the results of studies which led to the procedures for the chromatographic separation of radioactive strontium from alkaline, earth-alkaline and other elements in natural samples, on columns filled with strong base anion exchangers using alcoholic solutions of nitric acid as eluents. It has been shown that potassium, caesium, calcium, barium, yttrium and strontium can be adsorbed on strong base anion exchangers of the Dowex and Amberlite type, which contain the quaternary ammonium group with nitrate as counter-ion, from solutions of nitric acid in alcohol. Adsorption strength increases in the order methanol 3 in methanol, while they are adsorbed from ethanol and propanol. The adsorption strength is influenced by the polarity of alcohol, by the concentration of nitrate and by pH. The strength with which strontium adsorbs on the exchangers increases in the interval from 0 to 0.25M NH 4 NO 3 in methanol, after which it starts to decrease. Strontium adsorbs to the exchangers from the alcoholic solution of ammonium nitrate twice as strongly as from the alcoholic solution of nitric acid, while a fraction of water in pure alcohol exceeding 10% prevents adsorption. In the mixture of alcohol and nitric acid, the adsorption strength for calcium and strontium increases with the increase of the volume fraction of alcohol with a lower dielectric constant. The rate and strength of adsorption of ions on the exchanger also increase in the series 0.25M HNO 3 in methanol 3 in ethanol 3 in 1-propanol for each individual ion, as well as in the Ca 3 in methanol, 0.25M HNO 3 in ethanol and 0.25M HNO 3 in propanol. Separation is also possible from alcohol mixtures. Strontium separation is most difficult from calcium, while the efficiency of separation increases with a decrease of the polarity of the used alcohol or alcohol mixture. The first group elements of the periodic table are not separated from each other in this way, while the elements of the second group are

  19. Electromigration in molten salts and application to isotopic separation of alkaline and alkaline-earth elements

    International Nuclear Information System (INIS)

    Menes, F.


    The separation of the isotopes of the alkaline-earth elements has been studied using counter-current electromigration in molten bromides. The conditions under which the cathode operates as a bromine electrode for the highest possible currents have been examined. For the separation of calcium, it has been necessary to use a stable CaBr 2 - (CaBr 2 + KBr) 'chain'. In the case of barium and strontium, it was possible to employ the pure bromides. Enrichment factors of the order of 10 for 48 Ca and of the order of 1.5 for the rare isotopes of barium and strontium have been obtained. In the case of magnesium the method is slightly more difficult to apply because of material loss due to the relatively high vapour pressure of the salt requiring the use of electrolyte chains, MgBr 2 - CeBr 3 . A study has been made that has led to a larger-scale application of the method. These are essentially the inhibition of reversible operation of the cathode by traces of water, limiting the intensity which can be tolerated; evacuation of the heat produced by the Joule effect, in the absence of which the separation efficiency is reduced by thermal gradients; corrosion of the materials by molten salts at high temperature. Several cells capable of treating a few kilograms of substance have been put into operation; none of these has lasted long enough to produce a satisfactory enrichment. The method is thus limited actually to yields of the order of a few grams. (author) [fr

  20. Effects of alkaline concentration, temperature, and additives on the strength of alkaline-induced egg white gel. (United States)

    Zhao, Yan; Tu, Yonggang; Li, Jianke; Xu, Mingsheng; Yang, Youxian; Nie, Xuliang; Yao, Yao; Du, Huaying


    Egg whites can undergo gelation at extreme pH. In this paper, the effects of NaOH concentration (1.5, 2, 2.5, and 3%), temperature (10, 20, 30, and 40°C), and additives (metallic compounds, carbohydrates, stabilizers, and coagulants) on the strength of alkaline-induced egg white gel were investigated. Results showed that NaOH concentration and induced temperature significantly affected the rate of formation and peak strength of the egg white gel. Of the 6 metallic compounds used in this experiment, CuSO₄exhibited the optimal effect on the strength of alkaline-induced egg white gel, followed by MgCl₂, ZnSO4, PbO, and CaCl₂. When CuSO₄concentration was 0.2%, the gel strength increased by 31.92%. The effect of Fe₂(SO₄)₃was negligible. Of the 5 carbohydrate additives, xanthan gum (0.2%) caused the highest increase (54.31%) in the strength of alkaline-induced egg white gel, followed by sodium alginate, glucose, starch, and sucrose. Meanwhile, propylene glycol (0.25%) caused the highest improvement (15.78%) in the strength of alkaline-induced egg white gel among the 3 stabilizing agents and coagulants used, followed by Na₂HPO₄and glucono-δ-lactone. ©2014 Poultry Science Association Inc.