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Sample records for prussian blue analogue

  1. Hierarchically Superstructured Prussian Blue Analogues: Spontaneous Assembly Synthesis and Applications as Pseudocapacitive Materials

    SciTech Connect

    Yue, Yanfeng; Zhang, Zhiyong; Binder, Andrew J.; Chen, Jihua; Jin, Xianbo; Overbury, Steven; Dai, Sheng

    2014-11-10

    Hierarchically superstructured Prussian blue analogues (hexa- conventional hybrid graphene/MnO2 nanostructured textiles. cyanoferrate, M = NiII, CoII and CuII) are synthesized through Because sodium or potassium ions are involved in energy stor- a spontaneous assembly technique. In sharp contrast to mac- age processes, more environmentally neutral electrolytes can roporous-only Prussian blue analogues, the hierarchically su- be utilized, making the superstructured porous Prussian blue perstructured porous Prussian blue materials are demonstrated analogues a great contender for applications as high-per- to possess a high capacitance, which is similar to those of the formance pseudocapacitors.

  2. Hierarchically Superstructured Prussian Blue Analogues: Spontaneous Assembly Synthesis and Applications as Pseudocapacitive Materials

    DOE PAGES

    Yue, Yanfeng; Zhang, Zhiyong; Binder, Andrew J.; ...

    2014-11-10

    Hierarchically superstructured Prussian blue analogues (hexa- conventional hybrid graphene/MnO2 nanostructured textiles. cyanoferrate, M = NiII, CoII and CuII) are synthesized through Because sodium or potassium ions are involved in energy stor- a spontaneous assembly technique. In sharp contrast to mac- age processes, more environmentally neutral electrolytes can roporous-only Prussian blue analogues, the hierarchically su- be utilized, making the superstructured porous Prussian blue perstructured porous Prussian blue materials are demonstrated analogues a great contender for applications as high-per- to possess a high capacitance, which is similar to those of the formance pseudocapacitors.

  3. Dynamics of water in prussian blue analogues: Neutron scattering study

    SciTech Connect

    Sharma, V. K.; Mitra, S.; Thakur, N.; Yusuf, S. M.; Mukhopadhyay, R.; Juranyi, Fanni

    2014-07-21

    Dynamics of crystal water in Prussian blue (PB), Fe(III){sub 4}[Fe(II)(CN){sub 6}]{sub 3}.14H{sub 2}O and its analogue Prussian green (PG), ferriferricynaide, Fe(III){sub 4}[Fe(III)(CN){sub 6}]{sub 4}.16H{sub 2}O have been investigated using Quasielastic Neutron Scattering (QENS) technique. PB and its analogue compounds are important materials for their various interesting multifunctional properties. It is known that crystal water plays a crucial role towards the multifunctional properties of Prussian blue analogue compounds. Three structurally distinguishable water molecules: (i) coordinated water molecules at empty nitrogen sites, (ii) non-coordinated water molecules in the spherical cavities, and (iii) at interstitial sites exist in PB. Here spherical cavities are created due to the vacant sites of Fe(CN){sub 6} units. However, PG does not have any such vacant N or Fe(CN){sub 6} units, and only one kind of water molecules, exists only at interstitial sites. QENS experiments have been carried out on both the compounds in the temperature range of 260–360 K to elucidate the dynamical behavior of different kinds of water molecules. Dynamics is found to be much more pronounced in case of PB, compared to PG. A detailed data analysis showed that localized translational diffusion model could describe the observed data for both PB and PG systems. The average diffusion coefficient is found to be much larger in the PB than PG. The obtained domain of dynamics is found to be consistent with the geometry of the structure of the two systems. Combining the data of the two systems, a quantitative estimate of the dynamics, corresponding to the water molecules at different locations is made.

  4. Hydrogen adsorption in thin films of Prussian blue analogue

    SciTech Connect

    Yang, Dali; Ding, Vivian; Luo, Junhua; Currier, Robert P; Obrey, Steve; Zhao, Yusheng

    2008-01-01

    Quartz crystal microbalance with dissipation (QCM-D) measurement was used to investigate the kinetics of the molecular hydrogen adsorption into thin films of prussian blue analogues - Cu{sub 3}[Co(CN){sub 6}]{sub 2} at ambient conditions. Although the equilibrium adsorption seems to be independent of the thickness, the adsorption rate substantially decreases with the thickness of the films. In addition, the reversibility of H{sub 2} adsorption into the Cu{sub 3}[Co(CN){sub 6}]{sub 2} films was investigated. The results indicate that the Cu{sub 3}[Co(CN){sub 6}]{sub 2} maily interacts with H{sub 2} molecules physically. The highest H{sub 2} uptake by the Cu{sub 3}[Co(CN){sub 6}]{sub 2} films is obtained when the gas phase is stagnant inside the testing cell. However, the unusual high H{sub 2} uptake obtained from the QCM-D measurement makes us question how reliable this analytic methodology is.

  5. Synthesis of Bidimensional Prussian Blue Analogue Using an Inverted Langmuir-Schaefer Method.

    PubMed

    Rossos, Andreas K; Gengler, Régis Y N; Badali, Daniel S; Miller, R J Dwayne

    2016-09-27

    One of the aspects of modern materials science that has been captivating scientific interest for the past decade is low-dimensional systems. This stems from the fact that the physical, chemical, and biological properties of such systems are often vastly different from their bulk counterparts. Additionally, low-dimensionality structures frequently serve as a convenient platform for device applications. However, such materials are typically constructed from building blocks that are inherently three-dimensional, and so, from a morphological point of view, these can still be categorized as bulk powders or crystals. To push the boundaries of reduced dimensionality, we synthesized truly two-dimensional films of Prussian blue analogues (mixed valence tetracyanides) by combining an air-water interface reaction and a novel inverted Langmuir-Schaefer technique. The methodology introduced in this study offers control and tailoring over the Prussian blue analogues' film characteristics, which is an important step toward their incorporation into tangible applications. Standard isotherms were collected as a function of the initial reactant volume, and a number of characterization techniques such as X-ray photoelectron spectroscopy (XPS), UV-visible spectroscopy (UV-vis), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and atomic force microscopy (AFM) were performed on films transferred on various substrates. The results indicated a collection of single-crystalline and polycrystalline flakes possessing different thicknesses and having a structural coherence length of 11 ± 3 nm.

  6. Gd-Si oxide mesoporous nanoparticles with pre-formed morphology prepared from a Prussian blue analogue template.

    PubMed

    Cabrera-García, Alejandro; Vidal-Moya, Alejandro; Bernabeu, Ángela; Sánchez-González, Javier; Fernández, Eduardo; Botella, Pablo

    2015-08-21

    A novel approach to the synthesis of Gd-Si oxide mesoporous nanoparticles with a high Gd(3+) atom density and pre-formed morphology is presented. Prussian blue analogue Gd(H2O)4[Fe(CN)6], a metal organic framework that crystallizes in the orthorhombic system, is used for the first time as a sacrificial template by a reaction with soluble silicate. Simultaneous and stoichiometric condensation of gadolinium hydroxide and silica takes place, leading to dense and monodispersed nanoparticles that preserve the original shape and size of the Prussian blue analogue crystals. Then, porosity is developed by incorporation of cetyltrimethylammonium bromide under hydrothermal conditions. The obtained Gd-Si mesoporous oxide particles present a dual morphology of nanocrosses and nanorods and large surface areas.

  7. Switching magnetic interactions in the NiFe Prussian Blue Analogue: an ab initio inspection.

    PubMed

    Krah, Tim; Amor, Nadia Ben; Robert, Vincent

    2014-05-28

    The magnetic interaction in the Ni(ii)-Fe(iii) Prussian Blue Analogue is investigated by means of Difference Dedicated Configuration Interaction (DDCI) calculations. Embedded cluster calculations are performed to extract the exchange coupling constant J with respect to an opening of the Ni-NC-Fe bridge while maintaining a rigid Fe(CN)6 unit. It is shown that such active distortion significantly modifies the magnetic interaction scheme in the material. Not only a ferromagnetic to antiferromagnetic transition is observed, but the J value is varied from +11.4 cm(-1) to -12.5 cm(-1) when the Ni-Fe cyanide bridge is opened by 20°. The enhancement of the intersite hopping electron transfer integral by a factor of 1.5 can be correlated with the observed Na(+)-ion mobility in a unified "cation-coupled electron transfer" (CCET) process. These results stress the complexity and originality of this class of compounds evidenced by the versatility of their magnetic network.

  8. New Hybrid Nanomaterial Based on Self-Assembly of Cyclodextrins and Cobalt Prussian Blue Analogue Nanocubes

    PubMed Central

    Carvalho, Caio L. C.; Silva, Anna T. B.; Macedo, Lucyano J. A.; Luz, Roberto A. S.; Neto, José M. Moita; Filho, Ubirajara P. Rodrigues; Cantanhêde, Welter

    2015-01-01

    Supramolecular self-assembly has been demonstrated to be a useful approach to developing new functional nanomaterials. In this work, we used a cobalt Prussian blue analogue (PBA, Co3[Co(CN)6]2) compound and a β-cyclodextrin (CD) macrocycle to develop a novel host-guest PBA-CD nanomaterial. The preparation of the functional magnetic material involved the self-assembly of CD molecules onto a PBA surface by a co-precipitation method. According to transmission electronic microscopy results, PBA-CD exhibited a polydisperse structure composed of 3D nanocubes with a mean edge length of 85 nm, which became shorter after CD incorporation. The supramolecular arrangement and structural, crystalline and thermal properties of the hybrid material were studied in detail by vibrational and electronic spectroscopies and X-ray diffraction. The cyclic voltammogram of the hybrid material in a 0.1 mol·L−1 NaCl supporting electrolyte exhibited a quasi-reversible redox process, attributed to Co2+/Co3+ conversion, with an E1/2 value of 0.46 V (vs. SCE), with higher reversibility observed for the system in the presence of CD. The standard rate constants for PBA and PBA-CD were determined to be 0.07 and 0.13 s−1, respectively, which suggests that the interaction between the nanocubes and CD at the supramolecular level improves electron transfer. We expect that the properties observed for the hybrid material make it a potential candidate for (bio)sensing designs with a desirable capability for drug delivery. PMID:26132565

  9. Prussian blue analogue derived magnetic carbon/cobalt/iron nanocomposite as an efficient and recyclable catalyst for activation of peroxymonosulfate.

    PubMed

    Lin, Kun-Yi Andrew; Chen, Bo-Jau

    2017-01-01

    A Prussian blue analogue, cobalt hexacyanoferrate Co3[Fe(CN)6]2, was used for the first time to prepare a magnetic carbon/cobalt/iron (MCCI) nanocomposite via one-step carbonization of Co3[Fe(CN)6]2. The resulting MCCI consisted of evenly-distributed cobalt and cobalt ferrite in a porous carbonaceous matrix, making it an attractive magnetic heterogeneous catalyst for activating peroxymonosulfate (PMS). As Rhodamine B (RhB) degradation was adopted as a model test for evaluating activation capability of MCCI, factors influencing RhB degradation were thoroughly examined, including MCCI and PMS dosages, temperature, pH, salt and radical scavengers. A higher MCCI dosage noticeably facilitated the degradation kinetics, whereas insufficient PMS dosage led to ineffective degradation. RhB degradation by MCCI-activated PMS was much more favorable at high temperatures and under neutral conditions. The presence of high concentration of salt slightly interfered with RhB degradation by MCCI-activated PMS. Through examining effects of radical scavengers, RhB degradation by MCCI-activated PMS can be primarily attributed to sulfate radicals instead of a combination of sulfate and hydroxyl radicals. Compared to Co3O4, a typical catalyst for PMS activation, MCCI also exhibited a higher catalytic activity for activating PMS. In addition, MCCI was proven as a durable and recyclable catalyst for activating PMS over multiple cycles without efficiency loss and significant changes of chemical characteristics. These features demonstrate that MCCI, simply prepared from a one-step carbonization of Co3[Fe(CN)6]2 is a promising heterogeneous catalyst for activating PMS to degrade organic pollutants.

  10. Prussian blues as a cathode material for lithium ion batteries.

    PubMed

    Shen, Lian; Wang, Zhaoxiang; Chen, Liquan

    2014-09-22

    Prussian blues (or iron cyanides) and their analogues are attractive in both fundamental studies and industrial applications owing to their chemical and structural diversity. The large open space in their framework provides tunnels and space for the transport and storage of lithium ions. Two Prussian blues were synthesized by a co-precipitation method. The nanosized Fe4 [Fe(CN)6 ]3 and cubic FeFe(CN)6 deliver reversible capacities of 95 mAh g(-1) and 138 mAh g(-1) , respectively. In comparison, FeFe(CN)6 shows cycling and rate performances superior to Fe4 [Fe(CN)6 ]3 .

  11. Core-shell Prussian blue analogue molecular magnet Mn(1.5)[Cr(CN)6]·mH2O@Ni(1.5)[Cr(CN)6]·nH2O for hydrogen storage.

    PubMed

    Bhatt, Pramod; Banerjee, Seemita; Anwar, Sharmistha; Mukadam, Mayuresh D; Meena, Sher Singh; Yusuf, Seikh M

    2014-10-22

    Core-shell Prussian blue analogue molecular magnet Mn1.5[Cr(CN)6]·mH2O@Ni1.5[Cr(CN)6]·nH2O has been synthesized using a core of Mn1.5[Cr(CN)6]·7.5H2O, surrounded by a shell of Ni1.5[Cr(CN)6]·7.5H2O compound. A transmission electron microscopy (TEM) study confirms the core-shell nature of the nanoparticles with an average size of ∼25 nm. The core-shell nanoparticles are investigated by using x-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS) and elemental mapping, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and infrared (IR) spectroscopy. The Rietveld refinement of the XRD pattern reveals that the core-shell compound has a face-centered cubic crystal structure with space group Fm3m. The observation of characteristic absorption bands in the range of 2000-2300 cm(-1) in IR spectra corresponds to the CN stretching frequency of Mn(II)/Ni(II)-N≡C-Cr(III) sequence, confirming the formation of Prussian blue analogues. Hydrogen absorption isotherm measurements have been used to investigate the kinetics of molecular hydrogen adsorption into core-shell compounds of the Prussian blue analogue at low temperature conditions. Interestingly, the core-shell compound shows an enhancement in the hydrogen capacity (2.0 wt % at 123 K) as compared to bare-core and bare-shell compounds. The hydrogen adsorption capacity has been correlated with the specific surface area and TGA analysis of the core-shell compound. To the best of our knowledge, this is the first report on the hydrogen storage properties of core-shell Prussian blue analogue molecular magnet that could be useful for hydrogen storage applications.

  12. First principles calculation of a large variation in dielectric tensor through the spin crossover in the CsFe[Cr(CN){sub 6}] Prussian blue analogue

    SciTech Connect

    Middlemiss, Derek S. E-mail: R.J.Deeth@warwick.ac.uk; Deeth, Robert J. E-mail: R.J.Deeth@warwick.ac.uk

    2014-04-14

    The dielectric response of spin-crossover (SCO) materials is a key property facilitating their use in next-generation information processing technologies. Solid state hybrid density functional theory calculations show that the temperature-induced and strongly hysteretic SCO transition in the Cs{sup +}Fe{sup 2+}[Cr{sup 3+}(CN{sup −}){sub 6}] Prussian blue analogue (PBA) is associated with a large change (Δ) in both the static, Δε{sup 0}(HS − LS), and high frequency, Δε{sup ∞}(HS − LS) dielectric constants. The SCO-induced variation in CsFe[Cr(CN){sub 6}] is significantly greater than the experimental Δε values observed previously in other SCO materials. The phonon contribution, Δε{sup phon}(HS − LS), determined within a lattice dynamics approach, dominates over the clamped nuclei term, Δε{sup ∞}(HS − LS), and is in turn dominated by the low-frequency translational motions of Cs{sup +} cations within the cubic voids of the Fe[Cr(CN){sub 6}]{sup −} framework. The Cs{sup +} translational modes couple strongly to the large unit cell volume change occurring through the SCO transition. PBAs and associated metal-organic frameworks emerge as a potentially fruitful class of materials in which to search for SCO transitions associated with large changes in dielectric response and other macroscopic properties.

  13. Structural and magnetic properties of Prussian blue analogue molecular magnet Fe1.5[Cr(CN)6].mH2O

    NASA Astrophysics Data System (ADS)

    Bhatt, Pramod; Meena, S. S.; Mukadam, M. D.; Yusuf, S. M.

    2016-05-01

    Molecular magnets, based on Prussian blue analogues, Fe1.5[Cr(CN)6].mH2O have been synthesized in the bulk as well as nanoparticle forms using a co-precipitation method, and their structural and magnetic properties have been investigated using x-ray diffraction (XRD) Mössbauer spectroscopy and dc magnetization. The XRD study confirms the single phase crystalline and nanoparticle nature of the compounds with a face centered cubic (fcc) structure of space group Fm3m. The values of lattice constant are found to be ~10.18(5) Å and ~9.98(9)Å, for the bulk and nanoparticle samples, respectively. The dc magnetization shows a Curie temperature (TC) of ~17 K and ~5 K for the bulk and nanopartcile samples, respectively. The Mossouber spectroscopy reveal that the compound shows spin flipping from the high spin (HS) Fe (CrIII-C≡N-FeII) to low spin (LS) FeII ions (CrIII-N≡C-FeII). Moreover, the TC and the HS state of the Fe ions decreases (converts to its LS states) with time as well as in the nanoparticle form compared to bulk.

  14. First principles calculation of a large variation in dielectric tensor through the spin crossover in the CsFe[Cr(CN)6] Prussian blue analogue

    NASA Astrophysics Data System (ADS)

    Middlemiss, Derek S.; Deeth, Robert J.

    2014-04-01

    The dielectric response of spin-crossover (SCO) materials is a key property facilitating their use in next-generation information processing technologies. Solid state hybrid density functional theory calculations show that the temperature-induced and strongly hysteretic SCO transition in the Cs+Fe2+[Cr3+(CN-)6] Prussian blue analogue (PBA) is associated with a large change (Δ) in both the static, Δɛ0(HS - LS), and high frequency, Δɛ∞(HS - LS) dielectric constants. The SCO-induced variation in CsFe[Cr(CN)6] is significantly greater than the experimental Δɛ values observed previously in other SCO materials. The phonon contribution, Δɛphon(HS - LS), determined within a lattice dynamics approach, dominates over the clamped nuclei term, Δɛ∞(HS - LS), and is in turn dominated by the low-frequency translational motions of Cs+ cations within the cubic voids of the Fe[Cr(CN)6]- framework. The Cs+ translational modes couple strongly to the large unit cell volume change occurring through the SCO transition. PBAs and associated metal-organic frameworks emerge as a potentially fruitful class of materials in which to search for SCO transitions associated with large changes in dielectric response and other macroscopic properties.

  15. Self-assembly mechanism of nanoparticles of Ni-based Prussian Blue analogues at the air/liquid interface: a synchrotron X-ray reflectivity study.

    PubMed

    Giner-Casares, Juan J; Clemente-León, Miguel; Coronado, Eugenio; Brezesinski, Gerald

    2015-08-24

    Prussian Blue analogue (PBA) nanoparticles can be self-assembled at air/liquid interfaces to build novel materials with interesting magnetic features. Herein, we study the influence of the size of PBA Cs0.4 Ni[Cr(CN)6 ]0.9 and K0.25 Ni[Fe(CN)6 ]0.75 nanoparticles on the self-assembly behavior by synchrotron X-ray reflectivity. Both nanoparticles show similar Z-potential values. The phospholipid dipalmitoylphosphatidylcholine and the amino surfactant dimethyldioctadecylammonium have been used as Langmuir monolayers to anchor the PBA nanoparticles and study the interplay of forces directing the self-assembly of the nanoparticles at the surfactant/liquid interface. Whereas Cs0.4 Ni[Cr(CN)6 ]0.9 nanoparticles with a diameter of 8 nm form an incomplete layer at the surfactant/water interface, the larger K0.25 Ni[Fe(CN)6 ]0.75 nanoparticles with a diameter of 20 nm generate complete layers that can be stacked to one another. The size of the PBA nanoparticles is the main parameter determining the final arrangement at the air/liquid interface, due to the different extent of interparticle interaction. This study aims at the rationale design of PBA nanoparticles for an effective interfacial self-assembly, ultimately leading to functional materials.

  16. Prussian blue type nanoparticles for biomedical applications.

    PubMed

    Long, J; Guari, Y; Guérin, C; Larionova, J

    2016-11-28

    Prussian blue type nanoparticles are exciting nano-objects that combine the advantages of molecule-based materials and nanochemistry. Here we provide a short overview focalizing on the recent advances of these nano-objects designed for biomedical applications and give an outlook on the future research orientations in this domain.

  17. Prussian Blue Mg—Li Hybrid Batteries

    PubMed Central

    Sun, Xiaoqi; Duffort, Victor

    2016-01-01

    The major advantage of Mg batteries relies on their promise of employing an Mg metal negative electrode, which offers much higher energy density compared to graphitic carbon. However, the strong coulombic interaction of Mg2+ ions with anions leads to their sluggish diffusion in the solid state, which along with a high desolvation energy, hinders the development of positive electrode materials. To circumvent this limitation, Mg metal negative electrodes can be used in hybrid systems by coupling an Li+ insertion cathode through a dual salt electrolyte. Two “high voltage” Prussian blue analogues (average 2.3 V vs Mg/Mg2+; 3.0 V vs Li/Li+) are investigated as cathode materials and the influence of structural water is shown. Their electrochemical profiles, presenting two voltage plateaus, are explained based on the two unique Fe bonding environments. Structural water has a beneficial impact on the cell voltage. Capacities of 125 mAh g−1 are obtained at a current density of 10 mA g−1 (≈C/10), while stable performance up to 300 cycles is demonstrated at 200 mA g−1 (≈2C). The hybrid cell design is a step toward building a safe and high density energy storage system. PMID:27818909

  18. Prussian Blue Mg-Li Hybrid Batteries.

    PubMed

    Sun, Xiaoqi; Duffort, Victor; Nazar, Linda F

    2016-08-01

    The major advantage of Mg batteries relies on their promise of employing an Mg metal negative electrode, which offers much higher energy density compared to graphitic carbon. However, the strong coulombic interaction of Mg(2+) ions with anions leads to their sluggish diffusion in the solid state, which along with a high desolvation energy, hinders the development of positive electrode materials. To circumvent this limitation, Mg metal negative electrodes can be used in hybrid systems by coupling an Li(+) insertion cathode through a dual salt electrolyte. Two "high voltage" Prussian blue analogues (average 2.3 V vs Mg/Mg(2+); 3.0 V vs Li/Li(+)) are investigated as cathode materials and the influence of structural water is shown. Their electrochemical profiles, presenting two voltage plateaus, are explained based on the two unique Fe bonding environments. Structural water has a beneficial impact on the cell voltage. Capacities of 125 mAh g(-1) are obtained at a current density of 10 mA g(-1) (≈C/10), while stable performance up to 300 cycles is demonstrated at 200 mA g(-1) (≈2C). The hybrid cell design is a step toward building a safe and high density energy storage system.

  19. Magnetic carbon-supported cobalt derived from a Prussian blue analogue as a heterogeneous catalyst to activate peroxymonosulfate for efficient degradation of caffeine in water.

    PubMed

    Lin, Kun-Yi Andrew; Chen, Bo-Jau

    2017-01-15

    Extensive usage of caffeine (CAF) as a medicine and additives in beverages has led to increasing presence of CAF in wastewater and even drinking water. To remove CAF, peroxymonosulfate (PMS), is adopted to generate sulfate radical to degrade CAF in water. To facilitate PMS activation, a magnetic carbon-supported cobalt (MC/Co) hybrid material is prepared via carbonization of a cobalt-containing Prussian blue analogue framework (Co3[Co(CN)6]2). The resultant MC/Co contains Co and Co3O4 nanoparticles supported on a carbon matrix, making it an attractive magnetic catalyst to activate PMS for degrading CAF. MC/Co-activated PMS was shown to degrade CAF much more effectively than PMS and Co3O4-activated PMS. Parameters affecting CAF degradation by MC/Co-activated PMS were also examined, including MC/Co and PMS concentrations, temperature, pH, and salt. Effects of radical quenchers were also examined to provide insights into the CAF degradation mechanism. MC/Co-activated PMS was much more favorable at higher temperatures than ambient temperature, and under neutral conditions. Nevertheless, the presence of concentrated NaCl noticeably hindered CAF degradation. Through examining effects of radical quenchers, the mechanism of CAF degradation by MC/Co-activated PMS was attributed primarily to sulfate radicals and hydroxyl radicals to a lesser extent. The degradation products of CAF by MC/Co-activated PMS were also identified and a possible degradation pathway is proposed. MC/Co can activate PMS over multiple cycles without loss of catalytic activity. These findings demonstrate that MC/Co, simply prepared from simple carbonization of Co3[Co(CN)6]2 can be a promising heterogeneous catalyst for activating PMS to degrade CAF.

  20. Prussian blue: a new framework of electrode materials for sodium batteries.

    PubMed

    Lu, Yuhao; Wang, Long; Cheng, Jinguang; Goodenough, John B

    2012-07-04

    Prussian blue and its analogues consisting of different transition-metal ions (Fe, Mn, Ni, Cu, Co and Zn) have been synthesized at room temperature. Insertion of Na into KFe(2)(CN)(6) in a carbonate electrolyte exhibited a reversible capacity near 100 mA h g(-1) with no capacity fade in 30 cycles. The data indicate that a Na-ion battery with a Prussian blue framework as a cathode will be feasible.

  1. Scale-Activity Relationship of MnOx-FeOy Nanocage Catalysts Derived from Prussian Blue Analogues for Low-Temperature NO Reduction: Experimental and DFT Studies.

    PubMed

    Yan, Lijun; Liu, Yangyang; Zha, Kaiwen; Li, Hongrui; Shi, Liyi; Zhang, Dengsong

    2017-01-25

    Size effects have been recognized to promote the catalytic activity and selectivity of metal oxide particles. So far, limited works and studies are conducted to investigate the size effect of metal oxide with the tailored shape in the selective catalytic reduction of NOx with NH3 (NH3-SCR). Herein, the MnOx-FeOy nanocage catalysts with varied scales (0.25, 0.5, 1, and 2 μm) were synthesized via a Prussian blue analogue (PBA)-derived method and used for NH3-SCR of NO. By preforming a series of the activity tests over the nanocages with different scales, the NH3-SCR activity of 0.5 μm MnOx-FeOy nanocage catalysts exhibits the highest deNOx activity in the temperature range of 80-200 °C owing to more preferable physical and chemical properties. It has been demonstrated that there is a strong interaction among Mn and Fe cations in the 0.5 μm MnOx-FeOy nanocages. Moreover, the H2-TPR and XPS analysis prove 0.5 μm nanocages exhibit excellent redox properties, which contribute to the higher conservation of NOx. Through the DFT studies, it is also demonstrated that the 0.5 μm MnOx-FeOy nanocage catalysts could provide more preferable electronic charge, which gives rise to the varied adsorption behavior of the NH3 species and NOx species compared to the nanocages with other scales. The in situ DRIFTs were also employed to evaluate the adsorption status of NH3 with NOx species over MnOx-FeOy nanocage catalysts with varied scales. Finally, the scale-activity relationship of the MnOx-FeOy nanocage catalysts and their corresponding activities are also established. The deep insight into the scale-activity relationship of the PBA-derived MnOx-FeOy nanocage catalyst paves the way for developing and designing highly efficient Mn-based catalyst at lower temperature.

  2. Morphological synthesis of Prussian blue analogue Zn3[Fe(CN)6]2⋅xH2O micro-/nanocrystals and their excellent adsorption performance toward methylene blue.

    PubMed

    Wu, Shikui; Shen, Xiaoping; Zhou, Hu; Zhu, Guoxing; Wang, Rongyan; Ji, Zhenyuan; Chen, Kangmin; Chen, Chaojun

    2016-02-15

    Prussian blue analogue Zn3[Fe(CN)6]2⋅xH2O (Zn-PBA) micro-/nanocrystals with well-defined spherical, cubic and polyhedral morphologies have been successfully synthesized by a simple room-temperature solution method. The morphologies and sizes of the micro-/nanocrystals can be easily tuned by HCl dosage and polymer additive. The as-prepared products are characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis and Brunauer Emmet Teller adsorption-desorption analysis. The possible formation mechanism for these Zn-PBA micro-/nanocrystals is then proposed. In addtion, adsorption performances of these micro-/nanocrystals toward organic dyes are systematically investigated. It is demonstrated that they exhibit strong adsorption selectivity to methylene blue (MB) with an extraordinary adsorption capacity as high as 1.016gg(-1) due to the proper pore size and large specific surface area (643.2m(2)g(-1)) of the product as well as the strong electrostatic interaction between MB molecules and Zn-PBA particles. It is found that the morphology and size of the micro-/nanocrystals have an important effect on their adsorption performance. Moreover, the adsorbed MB dye can be well released in some organic solvents such as ethanol and trichloromethane. The facile morphology-controlled synthesis and excellent adsorption property afford the materials promising application in adsorption related fields.

  3. Removal of Radioactive Cesium Using Prussian Blue Magnetic Nanoparticles

    PubMed Central

    Jang, Sung-Chan; Hong, Sang-Bum; Yang, Hee-Man; Lee, Kune-Woo; Moon, Jei-Kwon; Seo, Bum-Kyoung; Huh, Yun Suk; Roh, Changhyun

    2014-01-01

    Radioactive cesium (137Cs) has inevitably become a human concern due to exposure from nuclear power plants and nuclear accident releases. Many efforts have been focused on removing cesium and the remediation of the contaminated environment. In this study, we elucidated the ability of Prussian blue-coated magnetic nanoparticles to eliminate cesium from radioactive contaminated waste. Thus, the obtained Prussian blue-coated magnetic nanoparticles were then characterized and examined for their physical and radioactive cesium adsorption properties. This Prussian blue-coated magnetic nanoparticle-based cesium magnetic sorbent can offer great potential for use in in situ remediation. PMID:28344255

  4. ²⁰¹Tl⁺-labelled Prussian blue nanoparticles as contrast agents for SPECT scintigraphy.

    PubMed

    Perrier, M; Busson, M; Massasso, G; Long, J; Boudousq, V; Pouget, J-P; Peyrottes, S; Perigaud, Ch; Porredon-Guarch, C; de Lapuente, J; Borras, M; Larionova, J; Guari, Y

    2014-11-21

    Prussian blue (PB) and its analogues on the nanometric scale are exciting nano-objects that combine the advantages of molecular-based materials and nanochemistry. Herein, we demonstrate that ultra-small PB nanoparticles of 2-3 nm can be easily labelled with radioactive (201)Tl(+) to obtain new nanoprobes as radiotracers for 201-thallium-based imaging.

  5. 201Tl+-labelled Prussian blue nanoparticles as contrast agents for SPECT scintigraphy

    NASA Astrophysics Data System (ADS)

    Perrier, M.; Busson, M.; Massasso, G.; Long, J.; Boudousq, V.; Pouget, J.-P.; Peyrottes, S.; Perigaud, Ch.; Porredon-Guarch, C.; de Lapuente, J.; Borras, M.; Larionova, J.; Guari, Y.

    2014-10-01

    Prussian blue (PB) and its analogues on the nanometric scale are exciting nano-objects that combine the advantages of molecular-based materials and nanochemistry. Herein, we demonstrate that ultra-small PB nanoparticles of 2-3 nm can be easily labelled with radioactive 201Tl+ to obtain new nanoprobes as radiotracers for 201-thallium-based imaging.Prussian blue (PB) and its analogues on the nanometric scale are exciting nano-objects that combine the advantages of molecular-based materials and nanochemistry. Herein, we demonstrate that ultra-small PB nanoparticles of 2-3 nm can be easily labelled with radioactive 201Tl+ to obtain new nanoprobes as radiotracers for 201-thallium-based imaging. Electronic supplementary information (ESI) available: Experimental details and procedures, toxicological data, PXRD, TEM images, kinetics and adsorption isotherms, SPECT/CT images, Tl+ captation profiles. See DOI: 10.1039/c4nr03044c

  6. Dehydrated Prussian Blues for CO2 Storage and Separation Applications

    SciTech Connect

    Motkuri, Radha K.; Thallapally, Praveen K.; McGrail, B. Peter; Ghorishi, Behrooz S.

    2010-08-13

    Adsorption isotherms of pure gases present in flue and natural gas including CO2, N2, CH4 and water were studied using prussian blues of chemical formula M3[Co(CN)6]2 (M = Cu, Ni, Mn). These materials adsorbed 8-12 wt % of CO2 at room temperature and 1 bar of pressure with heats of adsorption ranging from 6 to 16 kcal/mol.

  7. Prussian blue caged in spongiform adsorbents using diatomite and carbon nanotubes for elimination of cesium.

    PubMed

    Hu, Baiyang; Fugetsu, Bunshi; Yu, Hongwen; Abe, Yoshiteru

    2012-05-30

    We developed a spongiform adsorbent that contains Prussian blue, which showed a high capacity for eliminating cesium. An in situ synthesizing approach was used to synthesize Prussian blue inside diatomite cavities. Highly dispersed carbon nanotubes (CNTs) were used to form CNT networks that coated the diatomite to seal in the Prussian blue particles. These ternary (CNT/diatomite/Prussian-blue) composites were mixed with polyurethane (PU) prepolymers to produce a quaternary (PU/CNT/diatomite/Prussian-blue), spongiform adsorbent with an in situ foaming procedure. Prussian blue was permanently immobilized in the cell walls of the spongiform matrix and preferentially adsorbed cesium with a theoretical capacity of 167 mg/g cesium. Cesium was absorbed primarily by an ion-exchange mechanism, and the absorption was accomplished by self-uptake of radioactive water by the quaternary spongiform adsorbent.

  8. Magnetic Neutron Scattering of Thermally Quenched K-Co-Fe Prussian Blue

    SciTech Connect

    Pajerowski, Daniel M.; Garlea, Vasile O; Knowles, E. S.; Andrus, Matthew; Dumont, Matthieu; Calm, Yitzi; Nagler, Stephen E; Tong, Xin Tony; Talham, Daniel R.; Meisel, Mark W.

    2012-01-01

    Magnetic order in the thermally quenched photomagnetic Prussian blue analogue coordination polymer K0.27Co[Fe(CN)6]0.73[D2O6]0.27-1.42D2O has been studied down to 4 K with unpolarized and polarized neutron powder diraction as a function of applied magnetic eld. Analysis of the data allows the onsite coherent magnetization of the Co and Fe spins to be established. Specically, magnetic elds of 1 T and 4 T induce moments parallel to the applied eld, and the sample behaves as a ferromagnet with a wandering axis.

  9. Prussian Blue: A Potential Material to Improve the Electrochemical Performance of Lithium-Sulfur Batteries.

    PubMed

    Peng, Yueying; Li, Bing; Wang, Yunhui; He, Xinyi; Huang, Jianxing; Zhao, Jinbao

    2017-02-08

    The Prussian blue, as a potential adsorbent of polysulfides to suppress the dissolution and shuttle of polysulfides for lithium-sulfur batteries, has been studied in this work. Our results show that Prussian blue improves the electrochemical reaction kinetics during discharge/charge processes. More importantly, the cathode with Prussian blue exhibits better cycling stability and higher discharge capacity retention (722 mAh g(-1) at 0.2 A g(-1) after 100 cycles) than the one without Prussian blue (151 mAh g(-1)). These improvements of electrochemical performances are ascribed to the fact that Prussian blue is very effective in suppressing the dissolution of polysulfides into liquid electrolyte by chemical adsorption.

  10. Time resolved XANES illustrates a substrate-mediated redox process in Prussian blue cultural heritage materials

    NASA Astrophysics Data System (ADS)

    Gervais, Claire; Lanquille, Marie-Angélique; Moretti, Giulia; Réguer, Solenn

    2016-05-01

    The pigment Prussian blue is studied in heritage science because of its capricious fading behavior under light exposure. We show here that XANES can be used to study the photosensitivity of Prussian blue heritage materials despite X-ray radiation damage. We used an original approach based on X-ray photochemistry to investigate in depth the redox process of Prussian blue when it is associated with a cellulosic substrate, as in cyanotypes and watercolors. By modifying cation and proton contents of the paper substrate, we could tune both rate and extent of Prussian blue reduction. These results demonstrate that the photoreduction and fading of Prussian blue is principally mediated by the substrate and its interaction with the oxygen of the environment.

  11. Photoinduced ferrimagnetic systems in Prussian blue analogues C(I)xCo4[Fe(CN)6]y (C(I) = alkali cation). 4. Characterization of the ferrimagnetism of the photoinduced metastable state in Rb1.8Co4[Fe(CN)6]3.3-13H2O by K edges X-ray magnetic circular dichroism.

    PubMed

    Champion, G; Escax, V; Cartier Dit Moulin, C; Bleuzen, A; Villain, F; Baudelet, F; Dartyge, E; Verdaguer, M

    2001-12-19

    In Part 2 of this work, the electronic and local structure of the photoinduced metastable magnetic state of the Prussian blue analogue Rb1.8Co4[Fe(CN)6]3.3-13H2O were characterized. To determine directly the relative orientation of the magnetic moments of Co(II) and Fe(III) ions in the metastable state, and the nature of the exchange interaction between them, we performed X-ray magnetic circular dichroism (XMCD) experiments at the cobalt and iron K edges. We present the first direct experimental evidence of the antiferromagnetic interaction between the cobalt and the iron ions, leading to the ferrimagnetism of the photoinduced metastable state.

  12. Prussian Blue decorporation of {sup 137}Cs in beagles of different ages

    SciTech Connect

    Melo, D.R.; Lundgren, D.L.; Muggenburg, B.A.; Guilmette, R.A.

    1996-08-01

    A 6-wk study was conducted using immature (4.7 mo), young adult (2.4 y), and aged (13.5 y) male beagles to determine the modifying effect of age on the effectiveness of Prussian Blue decorporation therapy for the removal of injected {sup 137}Cs. Whole-body clearance rates for injected {sup 137}Cs decreased with increasing age in the dogs. Treatment with Prussian Blue changed the ratio of fecal to urinary {sup 137}Cs excretion from 0.8 in untreated dogs to 2.2 in treated animals. The {sup 137}Cs concentrations in tissues of untreated and Prussian Blue-treated dogs at the end of the 6-wk study were similar, with the greatest concentrations in the skeletal muscle tissue, spleen, and kidneys. There was a lower concentration of {sup 137}Cs in the livers of the treated dogs. The reductions in the average total whole-body doses resulting from Prussian Blue treatment during the course of this study were 51% in the immature, 31% in the young adult, and 38% in the aged dogs. Because of the differences in the intake of Prussian Blue by the dogs in the different groups relative to their body weight, it is unclear as to the relative effectiveness of Prussian Blue in dogs of different ages. 33 refs., 1 fig., 5 tabs.

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

  14. Self-powered biosensor for ascorbic acid with a Prussian blue electrochromic display.

    PubMed

    Zloczewska, Adrianna; Celebanska, Anna; Szot, Katarzyna; Tomaszewska, Dorota; Opallo, Marcin; Jönsson-Niedziolka, Martin

    2014-04-15

    We report on the development of a nanocarbon based anode for sensing of ascorbic acid (AA). The oxidation of AA on this anode occurs at a quite low overpotential which enables the anode to be connected to a biocathode to form an ascorbic acid/O2 biofuel cell that functions as a self-powered biosensor. In conjunction with a Prussian blue electrochromic display the anode can also work as a truly self-powered sensor. The oxidation of ascorbic acid at the anode leads to a reduction of the Prussian blue in the display. The reduced form of Prussian blue, called Prussian white, is transparent. The rate of change from blue to colourless is dependent on the concentration of ascorbic acid. The display can easily be regenerated by connecting it to the biocathode which returns the Prussian blue to its oxidized form. In this way we have created the first self-powered electrochromic sensor that gives quantitative information about the analyte concentration. This is demonstrated by measuring the concentration of ascorbic acid in orange juice. The reported quantitative read-out electrochromic display can serve as a template for the creation of cheap, miniturizable sensors for other relevant analytes.

  15. Quantitative determination of cesium binding to ferric hexacyanoferrate: Prussian blue.

    PubMed

    Faustino, Patrick J; Yang, Yongsheng; Progar, Joseph J; Brownell, Charles R; Sadrieh, Nakissa; May, Joan C; Leutzinger, Eldon; Place, David A; Duffy, Eric P; Houn, Florence; Loewke, Sally A; Mecozzi, Vincent J; Ellison, Christopher D; Khan, Mansoor A; Hussain, Ajaz S; Lyon, Robbe C

    2008-05-12

    Ferric hexacyanoferrate (Fe4III[FeII(CN)6]3), also known as insoluble Prussian blue (PB) is the active pharmaceutical ingredient (API) of the drug product, Radiogardase. Radiogardase is the first FDA approved medical countermeasure for the treatment of internal contamination with radioactive cesium (Cs) or thallium in the event of a major radiological incident such as a "dirty bomb". A number of pre-clinical and clinical studies have evaluated the use of PB as an investigational decorporation agent to enhance the excretion of metal cations. There are few sources of published in vitro data that detail the binding capacity of cesium to insoluble PB under various chemical and physical conditions. The study objective was to determine the in vitro binding capacity of PB APIs and drug products by evaluating certain chemical and physical factors such as medium pH, particle size, and storage conditions (temperature). In vitro experimental conditions ranged from pH 1 to 9, to cover the range of pH levels that PB may encounter in the gastrointestinal (GI) tract in humans. Measurements of cesium binding were made between 1 and 24h, to cover gastric and intestinal tract residence time using a validated atomic emission spectroscopy (AES) method. The results indicated that pH, exposure time, storage temperature (affecting moisture content) and particle size play significant roles in the cesium binding to both the PB API and the drug product. The lowest cesium binding was observed at gastric pH of 1 and 2, whereas the highest cesium binding was observed at physiological pH of 7.5. It was observed that dry storage conditions resulted in a loss of moisture from PB, which had a significant negative effect on the PB cesium binding capacity at time intervals consistent with gastric residence. Differences were also observed in the binding capacity of PB with different particle sizes. Significant batch to batch differences were also observed in the binding capacity of some PB API and

  16. Interlocked graphene-Prussian blue hybrid composites enable multifunctional electrochemical applications.

    PubMed

    Zhang, Minwei; Hou, Chengyi; Halder, Arnab; Ulstrup, Jens; Chi, Qijin

    2017-03-15

    There has been increasing interest recently in mixed-valence inorganic nanostructure functionalized graphene composites, represented by Prussian blue, because they can cost-effectively apply to biosensors and energy devices. In this work, we present a one-pot green method to synthesize interlocked graphene-Prussian Blue hybrid composites as high-performance materials for biosensors and supercapacitor electrodes. Given the fact that graphene oxide (GO) can act as an electron acceptor, we used iron(II) and glucose as co-reducing agents to reduce GO under mild reaction conditions without introducing toxic agents. High quality Prussian blue nanocubes with no or little coordinated water were generated simultaneously. Reduced graphene oxide (rGO) was thus functionalized by Prussian blue nanocubes via chemical bonding to form a kind of interlocked microstructure with high stability and good conductivity. The as-synthesized composites were tested for biosensing of hydrogen peroxide (H2O2) and as supercapacitor electrode materials. The specific capacitance of the microcomposite based electrodes can reach 428Fg(-1), with good cycling stability. The microcomposite also displays high performance catalysis towards electroreduction of H2O2 with a high sensitivity of 1.5Acm(-2)M(-1).

  17. Prussian Blue Coated Electrode as a Sensor for Electroinactive Cations in Aqueous Solutions

    ERIC Educational Resources Information Center

    Byrd, Houston; Chapman, Blake E.; Talley, Christopher L.

    2013-01-01

    Prussian Blue (PB) is an excellent material as a sensor for electroinactive cations because of its electrochemical behavior and its zeolytic character. A simple 3-h laboratory designed for a quantitative analysis or an instrumental methods course is reported. This laboratory studies the transport of various cations into a PB-modified electrode…

  18. Application of Prussian blue nanoparticles for the radioactive Cs decontamination in Fukushima region.

    PubMed

    Parajuli, Durga; Kitajima, Akiko; Takahashi, Akira; Tanaka, Hisashi; Ogawa, Hiroshi; Hakuta, Yukiya; Yoshino, Kazunori; Funahashi, Takayuki; Yamaguchi, Masaki; Osada, Mitsuo; Kawamoto, Tohru

    2016-01-01

    Cs decontamination efficiencies of the composites of iron hexacyanoferrate nanoparticles were investigated in comparison with commercial Prussian blue and natural zeolite. In pure water solution, the adsorption rate varied with sizes. In ash extract, where Cs adsorbing ability of zeolite was sharply dropped due to its poor selectivity, the impact of coexisting ions was negligible for FeHCF. FeHCF-n11, having the finest primary and secondary particle size, resulted the highest distribution coefficient, which was comparable to the high efficiency analogues, CoHCF or NiHCF. This observation suggested the possibility of preparing the high performance FeHCF by particle size and composition adjustment. FeHCF nanoparticle in bead form was tested for the removal of radioactive Cs in pilot scale. Due to larger secondary particle size, pronounced effect of solution temperature on the Cs adsorption kinetics on FeHCF bead was observed. Adjusting the mass of the adsorbent for the given solution temperature is recommended for achieving high decontamination rate.

  19. Reduction of cesium concentration in ovine tissues following treatment with Prussian Blue labeled with {sup 59}Fe

    SciTech Connect

    Ioannides, K.G.; Karamanis, D.T.; Stamoulis, K.C.

    1996-11-01

    The effectiveness of Prussian Blue in reducing the radiocesium contamination in ovine tissues was investigate. Five ewes were fed {sup 137}Cs-contaminated wheat for 30 d. When the {sup 137}Cs concentration in milk had reached equilibrium, one animal, serving as the control, was slaughtered and the activity in its tissues was measured. Two ewes were offered daily 1 g of Prussian Blue labeled with {sup 59}Fe in the Fe(III) position, outside the complex anion. One week after the administration of Prussian Blue, these animals were slaughtered, 1 wk apart, and the level of {sup 137}Cs in their tissues was measured. Comparing the concentration of {sup 137}Cs in the blood and tissues of the Prussian Blue treated animals to the corresponding concentrations measured in the control, a considerable reduction in the measured in the control, a considerable reduction in the radiocesium activity concentration is observed. However, {sup 137}Cs concentrations are maintained at non-zero (about 20%) values in the first 22 wk after the administration of Prussian Blue. This observation can be attributed to the fact that most of {sup 137}Cs binds to Prussian Blue in the animals` digestive tracts and the measured activity concentrations follow the elimination of cesium from tissues. Using a two-compartment mathematical model, we can predict the level of {sup 137}Cs in tissue, following the administration of Prussian Blue. Labeling Prussian Blue in the Fe(III)-position resulted in the measurement of a (2.4 {plus_minus} 0.02) % retention of Fe(III) in sheep. 23 refs., 2 figs., 5 tabs.

  20. Hyaluronic Acid Modified Hollow Prussian Blue Nanoparticles Loading 10-hydroxycamptothecin for Targeting Thermochemotherapy of Cancer

    PubMed Central

    Jing, Lijia; shao, shangmin; Wang, Yang; Yang, Yongbo; Yue, Xiuli; Dai, Zhifei

    2016-01-01

    This paper reported the fabrication of a multifunctional nanoplatform by modifying hollow Prussian blue nanoparticles with hyaluronic acid grafting polyethylene glycol, followed by loading 10-hydroxycamptothecin for tumor-targeted thermochemotherapy. It was found that the surface modification of hollow Prussian blue nanoparticles with hyaluronic acid grafting polyethylene endowed a great colloidal stability, long blood circulation time and the capability for targeting Hela cells over-expressing the CD44 receptor. The obtained nanoagent exhibited efficient photothermal effect and a light triggered and stepwise release behavior of 10-hydroxycamptothecin due to the strong optical absorption in the near-infrared region. The investigations on the body weight change, histological injury and blood biochemical indexes showed that such nanoagent had excellent biocompatibility for medical application. Both in vitro and in vivo experiments proved that the combination of chemotherapy and photothermal therapy through the agent of hyaluronic acid modified Prussian blue nanoparticles loading 10-hydroxycamptothecin could significantly improve the therapeutic efficacy compared with either therapy alone because of a good synergetic effect. PMID:26722372

  1. Hyaluronic Acid Modified Hollow Prussian Blue Nanoparticles Loading 10-hydroxycamptothecin for Targeting Thermochemotherapy of Cancer.

    PubMed

    Jing, Lijia; Shao, Shangmin; Wang, Yang; Yang, Yongbo; Yue, Xiuli; Dai, Zhifei

    2016-01-01

    This paper reported the fabrication of a multifunctional nanoplatform by modifying hollow Prussian blue nanoparticles with hyaluronic acid grafting polyethylene glycol, followed by loading 10-hydroxycamptothecin for tumor-targeted thermochemotherapy. It was found that the surface modification of hollow Prussian blue nanoparticles with hyaluronic acid grafting polyethylene endowed a great colloidal stability, long blood circulation time and the capability for targeting Hela cells over-expressing the CD44 receptor. The obtained nanoagent exhibited efficient photothermal effect and a light triggered and stepwise release behavior of 10-hydroxycamptothecin due to the strong optical absorption in the near-infrared region. The investigations on the body weight change, histological injury and blood biochemical indexes showed that such nanoagent had excellent biocompatibility for medical application. Both in vitro and in vivo experiments proved that the combination of chemotherapy and photothermal therapy through the agent of hyaluronic acid modified Prussian blue nanoparticles loading 10-hydroxycamptothecin could significantly improve the therapeutic efficacy compared with either therapy alone because of a good synergetic effect.

  2. Effect of alkali cations on heterogeneous photo-Fenton process mediated by Prussian blue colloids.

    PubMed

    Liu, Shou-Qing; Cheng, Shi; Feng, Lian-Rong; Wang, Xiao-Mei; Chen, Zhi-Gang

    2010-10-15

    This article evaluates Prussian blue (iron hexacyanoferrate) colloids as a heterogeneous photo-Fenton catalyst for the degradation of Rhodamine B. The emphasis is laid on the effects of alkali metal cations on the photo-Fenton process. The facts show that alkali cations strongly affect the degradation rate of organic species. The degradation rates of Rhodamine B, Malachite Green, and Methyl Orange in the presence of KCl, KNO(3), and K(2)SO(4), respectively, are faster than their degradation rates in the presence of the corresponding sodium salts. The average degradation rates of Rhodamine B in 0.2 M KCl, NaCl, RbCl, and CsCl solution, decline in sequence, and the rate in KCl solution is greater than that without any salt added deliberately. Thus, potassium ions accelerate the degradation rate, but sodium, rubidium, and cesium ions slow the rate. The order of the rates is R(K)>R>R(Na)>R(Rb)>R(Cs), which is consistent with that of the voltammetric oxidation currents of Prussian blue in the corresponding cation solutions. This phenomenon is attributed to the molecular recognition of the microstructure in Prussian blue nanoparticles to the alkali cations. The reaction mechanism of the photo-Fenton process has also been explored.

  3. A simple chemical method for deposition of electrochromic Prussian blue thin films

    SciTech Connect

    Demiri, Sani; Najdoski, Metodija; Velevska, Julijana

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer Prussian blue thin films were prepared by a simple chemical deposition method. Black-Right-Pointing-Pointer The films can be easily prepared from aqueous solution of Fe{sub 2}(SO{sub 4}){sub 3} and K{sub 4}[Fe(CN){sub 6}]. Black-Right-Pointing-Pointer The films show good electrochromic properties. Black-Right-Pointing-Pointer They change from deep blue color into green, and then back to blue and colorless. Black-Right-Pointing-Pointer The PB thin films exhibit stability and excellent reversibility. -- Abstract: This paper is about a recently developed new chemical method for deposition of Prussian blue thin films. The films are easily prepared by successive immersion of the substrates into an acidic aqueous solution of Fe{sub 2}(SO{sub 4}){sub 3} and K{sub 4}[Fe(CN){sub 6}]. It is calculated of the results from AFM analysis that the growth in the film thickness by one immersion cycle corresponds to an average increase of 6 nm. The characterization of the films with X-ray diffraction, SEM-EDS analysis and FTIR spectroscopy shows that the deposited material is amorphous hydrated Fe{sub 4}[Fe(CN){sub 6}]{sub 3}. The electrochromic properties are characterized by cyclic voltammetry and VIS spectrophotometry. The PB thin films exhibit stability and excellent reversibility, which make these films favorable for electrochromic devices.

  4. A Database of the Structural and Electronic Properties of Prussian Blue, Prussian White, and Berlin Green Compounds through Density Functional Theory.

    PubMed

    Hegner, Franziska Simone; Galán-Mascarós, José Ramón; López, Núria

    2016-12-19

    Prussian blue and its related compounds are formed by cheap and abundant metals and have shown their importance in the generation of new fuels by renewable sources. To optimize these compounds it is important to understand their electronic structure and thus establish robust structure-activity relationships. To this end, we employed theoretical simulations based on density functional theory, employing functionals of different degree of complexity, including pure generalized gradient approximation (GGA) and GGA+U functionals, which introduce self-interaction correction terms through the Hubbard parameter, and compared those to the hybrid functionals HSE03 and HSE06. With this robust setup, we can identify an appropriate computational scheme that provides the best compromise between computational demand and accuracy. A complete database considering Berlin green and Prussian blue and white for all alkaline cations is presented.

  5. Lithium intercalation properties in manganese-iron Prussian blue analogues

    NASA Astrophysics Data System (ADS)

    Matsuda, T.; Kurihara, Y.; Moritomo, Y.

    2013-04-01

    We investigated the electronic states and structural properties of LixMn[Fe(CN)6]0.83·3.5H2O, and LixMn[Fe(CN)6]0.87·2.6H2O, which have different amount of [Fe(CN)6] vacancies. X-ray absorption spectra near the Fe and Mn K-edges revealed that the Li intercalation/deintercalation process is two-electron reaction, i.e. MnII—NC—FeII, MnII—NC—FeIII, and MnIII—NC—FeIII. The crystal structure of LixMn[Fe(CN)6]0.83·3.5H2O remains cubic and single phase throughout the Li intercalation/deintercalation process. The crystal structure of LixMn[Fe(CN)6]0.87·2.6H2O is also cubic, while phase separation of Li+-rich phase and Li+-poor phase was observed during the MnII/MnIII reduction/oxidation process.

  6. Monte Carlo simulation of Prussian blue analogs described by Heisenberg ternary alloy model

    NASA Astrophysics Data System (ADS)

    Yüksel, Yusuf

    2015-11-01

    Within the framework of Monte Carlo simulation technique, we simulate magnetic behavior of Prussian blue analogs based on Heisenberg ternary alloy model. We present phase diagrams in various parameter spaces, and we compare some of our results with those based on Ising counterparts. We clarify the variations of transition temperature and compensation phenomenon with mixing ratio of magnetic ions, exchange interactions, and exchange anisotropy in the present ferro-ferrimagnetic Heisenberg system. According to our results, thermal variation of the total magnetization curves may exhibit N, L, P, Q, R type behaviors based on the Néel classification scheme.

  7. Prussian Blue Nanoparticles for the Enrichment of Radioactive Cesium in Solutions - 13275

    SciTech Connect

    Parajuli, Durga; Kitajima, Akiko; Tanaka, Hisashi; Kawamoto, Tohru

    2013-07-01

    Prussian blue (PB) nanoparticles in different form were studied for the adsorptive enrichment of Cs in solutions. Water dispersible nano-PB was found to be highly effective on removing trace level Cs in stagnant waters. The nano-PB loaded filters were effective on collecting Cs in flow systems like river water, thus provides a big relief on controlling the environmental mobility of Cs and its entry to the productive lands via water. Water insoluble nano-PB adsorbent possesses high Cs loading capacity and selectivity and it is found to be the ultimate option for the systems containing high concentration Cs. (authors)

  8. Synthesis of gold coated magnetic microparticles and their application for electrochemical glucose sensing by the enzymatically precipitated prussian blue.

    PubMed

    Jung, Hye Young; Park, Jun Hui; Hwang, Seongpil; Kwak, Juhyoun

    2013-05-01

    An enzyme stimulated deposition of prussian blue onto the gold-coated magnetic microparticles is described. We propose to synthesize the continuous outer gold layer on the magnetic particle for a gold working electrode and its superparamagnetic property. In-depth characterization of the gold shell formation was studied with scanning electron microscopy, energy-dispersive X-ray spectroscopy, cyclic voltammetry. The gold-coated magnetic microparticles offered adhesive layer for the immobilization of glucose oxidase catalyzing the generation of prussian blue in the presence of glucose. The assembled prussian blue on the gold shell surfaces was detected with electrochemical measurements depending on the glucose concentration. With accomplishing the linear response range from 0.2 mM to 10 mM of glucose, this approach successfully proposed the applicability of the magnetic core-gold shell structures to the electrochemical bioassay area.

  9. Spectrophotometric Determination of 6-Propyl-2-Thiouracil in Pharmaceutical Formulations Based on Prussian Blue Complex Formation: An Undergraduate Instrumental Analysis Laboratory Experiment

    ERIC Educational Resources Information Center

    Zakrzewski, Robert; Skowron, Monika; Ciesielski, Witold; Rembisz, Zaneta

    2016-01-01

    The laboratory experiment challenges students to determine 6-propyl-2-thiouracil (PTU) based on Prussian blue complex formation. Prussian blue is formed by ferricyanide and Fe(II) ions which are generated in situ from Fe(III) ions reduced by PTU. The absorbance of this product was measured at a wavelength of 840 nm, after a reaction time of 30…

  10. Prussian Blue

    MedlinePlus

    ... 192) Plutonium Radioisotope Brief Toxicological Profile Toxicology FAQs Polonium-210 Q & A: Information about Public Health Issues Related to Polonium-210 Contamination in the United Kingdom Guidance for Public ...

  11. Facile synthesis of pectin-stabilized magnetic graphene oxide Prussian blue nanocomposites for selective cesium removal from aqueous solution.

    PubMed

    Kadam, Avinash A; Jang, Jiseon; Lee, Dae Sung

    2016-09-01

    This work focused on the development of pectin-stabilized magnetic graphene oxide Prussian blue (PSMGPB) nanocomposites for removal of cesium from wastewater. The PSMGPB nanocomposite showed an improved adsorption capacity of 1.609mmol/g for cesium, compared with magnetic graphene oxide Prussian blue, magnetic pectin Prussian blue, and magnetic Prussian blue nanocomposites, which exhibited adsorption capacities of 1.230, 0.901, and 0.330mmol/g, respectively. Increased adsorption capacity of PSMGPB nanocomposites was attributed to the pectin-stabilized separation of graphene oxide sheets and enhanced distribution of magnetites on the graphene oxide surface. Scanning electron microscopy images showed the effective separation of graphene oxide sheets due to the incorporation of pectin. The optimum temperature and pH for adsorption were 30°C and 7.0, respectively. A thermodynamic study indicated the spontaneous and the exothermic nature of cesium adsorption. Based on non-linear regression, the Langmuir isotherm fitted the experimental data better than the Freundlich and Tempkin models.

  12. Prussian blue-modified nanoporous gold film electrode for amperometric determination of hydrogen peroxide.

    PubMed

    Ghaderi, Seyran; Mehrgardi, Masoud Ayatollahi

    2014-08-01

    In this manuscript, the electrocatalytic reduction of hydrogen peroxides on Prussian blue (PB) modified nanoporous gold film (NPGF) electrode is described. The PB/NPGF is prepared by simple anodizing of a smooth gold film followed by PB film electrodeposition method. The morphology of the PB/NPGF electrode is characterized using scanning electron microscopy (SEM). The effect of solution pH and the scan rates on the voltammetric responses of hydrogen peroxide have also been examined. The amperometric determination of H2O2 shows two linear dynamic responses over the concentration range of 1μM-10μM and 10μM-100μM with a detection limit of 3.6×10(-7)M. Furthermore, this electrode demonstrated good stability, repeatability and selectivity remarkably.

  13. Thallium(I) sorption using Prussian blue immobilized in alginate capsules.

    PubMed

    Vincent, Thierry; Taulemesse, Jean-Marie; Dauvergne, Agnès; Chanut, Thomas; Testa, Flaviano; Guibal, Eric

    2014-01-01

    Prussian blue (PB) was immobilized in alginate capsules. The composite sorbent was used for the recovery of Tl(I) ions from slightly acidic solutions: optimum pH being close to 4. The sorption isotherm can be described by the bi-site Langmuir sorption isotherm. This means that the metal ion can be bound through two different sorption sites: one having a strong affinity for Tl(I) (probably PB), the other having a lower affinity (probably the encapsulating material). The kinetics are described by either the pseudo-second order rate equation or the Crank's equation (resistance to intraparticle diffusion). The ionic strength (increased by addition of NaCl, KCl or CaCl₂) slightly decreased sorption capacity. The SEM-EDX analysis of PB-alginate capsules (before and after Tl(I) sorption) shows that the PB is homogeneously distributed in the capsules and that all reactive groups remain available for metal binding.

  14. High performance Prussian Blue cathode for nonaqueous Ca-ion intercalation battery

    NASA Astrophysics Data System (ADS)

    Kuperman, Neal; Padigi, Prasanna; Goncher, Gary; Evans, David; Thiebes, Joseph; Solanki, Raj

    2017-02-01

    Potassium iron hexacyanoferrate, or Prussian blue (PB), is investigated as a cathode material for nonaqueous divalent calcium ion batteries. PB is an attractive prospect due to its high specific capacity, nontoxicity, low cost, and simple synthesis. Charge/discharge performances are examined at current densities of 23 mAg-1, 45 mAg-1, 90 mAg-1, and 125 mAg-1 that produced reversible specific capacities ranging from 150 mAhg-1 (at 23 mAg-1 current density) to over 120 mAhg-1 (at 125 mAg-1 current density). These are the highest storage capacities to date for a divalent calcium ion cathode over extended period of charge/discharge cycling and are comparable in performance to monovalent intercalating ions.

  15. Changeover during in situ compositional modulation of hexacyanoferrate (Prussian Blue) material.

    PubMed

    Bueno, Paulo Roberto; Giménez-Romero, David; Gabrielli, Claude; García-Jareño, José Juan; Perrot, Hubert; Vicente, Francisco

    2006-12-27

    This paper describes the importance of (H2O)6 clusters in controlling the properties of hexacyanoferrate (Prussian Blue) materials. A careful in situ study of compositional changes by using electrogravimetric techniques (in ac and dc modes) in hexacyanoferrates containing K+ alkali metals reveals the existence of a changeover in the properties of these films in a narrow potential range. Control of the compositional variation of the changeover is dependent on the K+ stoichiometric number in the compound structure. However, a specific K+ occupation in the compound structure activates the occupation of the (H2O)6 cluster by H3O+ and/or H+, causing the changeover in the properties of hexacyanoferrate film. Thus, the information thus obtained is very useful for understanding the mechanisms involved in the electrochemical reversible switch between ferrimagnetism/paramagnetism, "semiconductor/metal" and electroluminescence/nonelectroluminescence properties of molecular cyanide materials.

  16. A Novel Electrochemical Detector using Prussian Blue Modified Indium Tin Oxide Electrode

    NASA Astrophysics Data System (ADS)

    Yi, In-Je; Kim, Ju-Ho; Kang, C. J.; Choi, Y. J.; Lee, Kisay; Kim, Yong-Sang

    2006-01-01

    We propose a novel electrochemical detector (ECD) to catalyze redox efficiently by electrodepositing Prussian blue (PB, ferric hexacyanoferrate) on the indium tin oxide (ITO) electrode. Capillary electrophoresis (CE) and amperometric methods were used. We investigated the PB surface properties by topography from atomic force microscopy (AFM). The PB film on dense and smooth surfaces could catalyze redox reaction efficiently. Compared with CE-ECD microchips using a bare-ITO electrode, the proposed CE-ECD microchip using a PB modified electrode has shown better sensitivity of the electropherograms. It has been verified that wide-ranging detection can be performed under the limits of 0.01 mM of dopamine and catechol respectively when we use a PB modified electrode.

  17. Ion permeability of polydopamine films revealed using a Prussian blue-based electrochemical method.

    PubMed

    Gao, Bowen; Su, Lei; Tong, Ying; Guan, Miao; Zhang, Xueji

    2014-11-06

    Polydopamine (PDA) is fast becoming a popular surface modification technique. Detailed understanding of the ion permeability properties of PDA films will improve their applications. Herein, we report for the first time the thickness-independent ion permeability of PDA films using a Prussian blue (PB)-based electrochemical method. In this method, PDA films are deposited via ammonium persulfate-induced dopamine polymerization onto a PB electrode. The ion permeability of the PDA films can thus be detected by observing the changes in electrochemical behaviors of the PB coated by PDA films. On the basis of this method, it was unexpectedly found that the PDA films with thickness greater than 45 nm (e.g., ~60 and ~113 nm) can exhibit pH-switchable but thickness-insensitive permeability to monovalent cations such as potassium and sodium ions. These observations clearly indicate the presence of a continuous network of interconnected intermolecular voids within PDA films, regardless of film thickness.

  18. Prussian blue @ platinum nanoparticles/graphite felt nanocomposite electrodes: application as hydrogen peroxide sensor.

    PubMed

    Han, Lijuan; Tricard, Simon; Fang, Jian; Zhao, Jihua; Shen, Weiguo

    2013-05-15

    In this study, we report a triple-component sensor fabricated by freestanding graphite felt (GF), platinum nanoparticles (Pt) and Prussian blue (PB). Pt is ultrasonically-electrodeposited on GF to increase the conductivity and to render the catalysts to the chemical deposition of PB. Cyclic voltammetric and amperometric measurements show that the double porous PB@Pt/GF sensor exhibits two pairs of well-defined redox peaks and a prominent electrocatalytic activity toward H2O2 reduction. This resulting sensor displays impressive results with regard to a low detection limit of 1.2×10(-9)M and very high detection sensitivity of 40.9Acm(-2)M(-1), using a potential work of 0.0V.

  19. A glucose biosensor based on Prussian blue/chitosan hybrid film.

    PubMed

    Wang, Xueying; Gu, Haifang; Yin, Fan; Tu, Yifeng

    2009-01-01

    Based on electrodeposition of Prussian blue (PB) and chitosan (CS) directly on gold electrode, a hybrid film of PB/CS has been prepared. PB in this film shows a good stability compared with pure PB film when it worked in neutral and weak alkalescent solution and can act as redox mediator. It provides the potential application of such film in biosensor fabrication. A glucose biosensor was fabricated by electrodepositing glucose oxidase (GOD)/CS film on this PB/CS modified electrode. The optimum experimental conditions of biosensor for the detection of glucose have been studied in detail. Under the optimal conditions, a linear dependence of the catalytic current upon glucose concentration was obtained in the range of 2x10(-6) to 4x10(-4)M with a detection limit of 3.97x10(-7)M. The resulting biosensor could be applied to detect the blood sugar in real samples without any pretreatment.

  20. Graphene oxide sheet-prussian blue nanocomposites: green synthesis and their extraordinary electrochemical properties.

    PubMed

    Liu, Xiao-Wang; Yao, Zi-Jian; Wang, Yue-Feng; Wei, Xian-Wen

    2010-12-01

    A facile and green method for the synthesis of graphene oxide sheets (GOs)-prussian blue nanocomposites has been presented via a spontaneous redox reaction in a aqueous solution containing FeCl3, K3[Fe(CN)6] and graphene oxide sheets. Electrochemical property investigation demonstrates PB nanocubes formed on the surface of GOs retain their excellent electrochemical activity and the GOs can enhance the electron transfer between PB and GC electrode. Moreover, the obtained nanocomposites even have shown a higher sensitivity toward the electrocatalytical reduction of H2O2 than that of multiwalled carbon nanotube/PB nanocomposites. Given their extraordinary electrochemical properties and the green preparation, as-prepared GO-PB nanocomposites have great potential in the field of electrochemical sensor and biofuel cell.

  1. Hydrogels Containing Prussian Blue Nanoparticles Toward Removal of Radioactive Cesium Ions.

    PubMed

    Kamachi, Yuichiro; Zakaria, Mohamed B; Torad, Nagy L; Nakato, Teruyuki; Ahamad, Tansir; Alshehri, Saad M; Malgras, Victor; Yamauchil, Yusuke

    2016-04-01

    Recent reports have demonstrated the practical application of Prussian blue (PB) nanoparticles toward environmental clean-up of radionuclide 173Cs. Herein, we prepared a large amount of PB nanoparticles by mixing both iron(III) chloride and sodium ferrocyanide hydrate as starting precursors. The obtained PB nanoparticles show a high surface area (440 m2. g-1) and consequently an excellent uptake ability of Cs ions from aqueous solutions. The uptake ability of Cs ions into poly(N-isopropylacrylamide (PNIPA) hydrogel is drastically increased up to 156.7 m2. g-1 after incorporating our PB nanoparticles, compared to 30.2 m2 . g-1 after using commercially available PB. Thus, our PB-containing PNIPA hydrogel can be considered as an excellent candidate for the removal of Cs ions from aqueous solutions, which will be useful for the remediation of the nuclear waste.

  2. A DNA biosensor based on graphene paste electrode modified with Prussian blue and chitosan.

    PubMed

    Bo, Yang; Wang, Weiqi; Qi, Junfei; Huang, Shasheng

    2011-05-07

    A chemically modified graphene paste electrode was prepared by incorporating appropriate amounts of graphene in a paste mixture, followed by electrodepositing Prussian blue (PB) and coating chitosan on the electrode surface. The electrode was able to bind ssDNA, and gave a better voltammetric response for complement DNA than did ordinary carbon paste electrodes. The response of the electrode was characterized with respect to the paste composition, immobilization time of probe DNA on the chitosan and PB modified graphene paste electrode, and the effect of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC). The electrochemical behavior of PB assembled on the graphene paste electrode was investigated. The combination of graphene and PB can enhance the current response of the graphene paste electrode. As a consequence of DNA hybridization, a significant change in the current due to daunomycin intercalated with double-stranded DNA (ds-DNA) on the surface of the graphene paste electrode was observed.

  3. Laccase-Prussian blue film-graphene doped carbon paste modified electrode for carbamate pesticides quantification.

    PubMed

    Oliveira, Thiago M B F; Fátima Barroso, M; Morais, Simone; Araújo, Mariana; Freire, Cristina; de Lima-Neto, Pedro; Correia, Adriana N; Oliveira, Maria B P P; Delerue-Matos, Cristina

    2013-09-15

    A novel enzymatic biosensor for carbamate pesticides detection was developed through the direct immobilization of Trametes versicolor laccase on graphene doped carbon paste electrode functionalized with Prussian blue films (LACC/PB/GPE). Graphene was prepared by graphite sonication-assisted exfoliation and characterized by transmission electron microscopy and X-ray photoelectron spectroscopy. The Prussian blue film electrodeposited onto graphene doped carbon paste electrode allowed considerable reduction of the charge transfer resistance and of the capacitance of the device. The combined effects of pH, enzyme concentration and incubation time on biosensor response were optimized using a 2(3) full-factorial statistical design and response surface methodology. Based on the inhibition of laccase activity and using 4-aminophenol as redox mediator at pH 5.0, LACC/PB/GPE exhibited suitable characteristics in terms of sensitivity, intra- and inter-day repeatability (1.8-3.8% RSD), reproducibility (4.1 and 6.3% RSD), selectivity (13.2% bias at the higher interference:substrate ratios tested), accuracy and stability (ca. twenty days) for quantification of five carbamates widely applied on tomato and potato crops. The attained detection limits ranged between 5.2×10(-9)molL(-1) (0.002mgkg(-1) w/w for ziram) and 1.0×10(-7)molL(-1) (0.022mgkg(-1) w/w for carbofuran). Recovery values for the two tested spiking levels ranged from 90.2±0.1 (carbofuran) to 101.1±0.3% (ziram) for tomato and from 91.0±0.1% (formetanate) to 100.8±0.1% (ziram) for potato samples. The proposed methodology is appropriate to enable testing pesticide levels in food samples to fit with regulations and food inspections.

  4. Facile Synthesis of Prussian Blue Derivate-Modified Mesoporous Material via Photoinitiated Thiol-Ene Click Reaction for Cesium Adsorption.

    PubMed

    Qian, Jun; Ma, Jiaqi; He, Weiwei; Hua, Daoben

    2015-08-01

    A novel strategy to synthesize a functional mesoporous material for efficient removal of cesium is reported. Specifically, Prussian blue derivate-modified SBA-15 (SBA-15@FC) was prepared by photoinitiated thiol-ene reaction between thiol-modified SBA-15 and pentacyano(4-vinyl pyridine)ferrate complex. The effects of weight percentage of the Prussian blue derivate, pH, adsorbent dose, co-existing ions, and initial concentration were evaluated on the adsorption of cesium ions. The adsorption kinetically follows a pseudo-second-order model and reaches equilibrium within 2 h with a high adsorption capacity of about 13.90 mg Cs g(-1) , which indicates that SBA-15@FC is a promising adsorbent to effectively remove cesium from aqueous solutions.

  5. Toxicological evaluation of Prussian blue nanoparticles after short exposure of mice.

    PubMed

    Chen, Y; Wu, L; Wang, Q; Wu, M; Xu, B; Liu, X; Liu, J

    2016-10-01

    Prussian blue nanoparticle (PBNP), a new type of theranostic nanomaterial, had been used for cancer magnetic resonance imaging and photothermal therapy. However, their long-term toxicity after short exposure in vivo was still unclear. In this study, we investigated the dynamic changes of the biochemical and immunity indicators of mice after PBNPs injection through tail vein. Histological results showed that the PBNPs were mainly accumulated in liver and spleen. In the spleen, we found the frequency of T cells was starting to decrease after 1 day of PBNPs injection, but then slowly recovered to normal level after 60 days of injection. Meanwhile, the frequency of T cells in the blood was firstly decreased after the PBNPs injection, and then the T cell frequency kept increasing and recovered back to normal levels after 7 days of injection. The serum indexes of liver functions (alanine transaminase, aspartate transaminase, total bilirubin, and alkaline phosphatase) increased rapidly to a relatively high level only after 1 h of injection, which meant certain acute liver damage, but these indexes were gradually decreased to normal levels after 60 days of injection. These results indicate that PBNPs have acute toxicity in vivo, however, their long-term toxicity after short-time exposure is low, which might provide guidance for further applications of PBNPs in future.

  6. Hyaluronic Acid Conjugated Magnetic Prussian Blue@Quantum Dot Nanoparticles for Cancer Theranostics

    PubMed Central

    Yang, Yongbo; Jing, Lijia; Li, Xiaoda; Lin, Li; Yue, Xiuli; Dai, Zhifei

    2017-01-01

    A multifunctional nanotheranostic agent was developed by conjugating both hyaluronic acid and bovine serum albumin coated CuInS2-ZnS quantum dots onto the surface of magnetic Prussian blue nanoparticles. The obtained nanoagent could serve as an efficient contrast agent to simultaneously enhance near infrared (NIR) fluorescence and magnetic resonance (MR) imaging greatly. The coexistence of magnetic core and CD44 ligand hyaluronic acid was found to largely improve the specific uptake of the nanoagent by CD44 overexpressed HeLa cells upon applying an external magnetic field. Both NIR fluorescence and MR imaging in vivo proved high accumulation of the nanoagent at tumor site due to its excellent CD44 receptor/magnetic dual targeting capability. After intravenous injection of the nanoagent and treatment of external magnetic field, the tumor in nude mice was efficiently ablated upon NIR laser irradiation and the tumor growth inhibition was more than 89.95%. Such nanotheranostic agent is of crucial importance for accurately identifying the size and location of the tumor before therapy, monitoring the photothermal treatment procedure in real-time during therapy, assessing the effectiveness after therapy. PMID:28255343

  7. Cellulose nanofiber backboned Prussian blue nanoparticles as powerful adsorbents for the selective elimination of radioactive cesium

    PubMed Central

    Vipin, Adavan Kiliyankil; Fugetsu, Bunshi; Sakata, Ichiro; Isogai, Akira; Endo, Morinobu; Li, Mingda; Dresselhaus, Mildred S.

    2016-01-01

    On 11 March 2011, the day of the unforgettable disaster of the 9 magnitude Tohoku earthquake and quickly followed by the devastating Tsunami, a damageable amount of radionuclides had dispersed from the Fukushima Daiichi’s damaged nuclear reactors. Decontamination of the dispersed radionuclides from seawater and soil, due to the huge amounts of coexisting ions with competitive functionalities, has been the topmost difficulty. Ferric hexacyanoferrate, also known as Prussian blue (PB), has been the most powerful material for selectively trapping the radioactive cesium ions; its high tendency to form stable colloids in water, however, has made PB to be impossible for the open-field radioactive cesium decontamination applications. A nano/nano combinatorial approach, as is described in this study, has provided an ultimate solution to this intrinsic colloid formation difficulty of PB. Cellulose nanofibers (CNF) were used to immobilize PB via the creation of CNF-backboned PB. The CNF-backboned PB (CNF/PB) was found to be highly tolerant to water and moreover, it gave a 139 mg/g capability and a million (106) order of magnitude distribution coefficient (Kd) for absorbing of the radioactive cesium ion. Field studies on soil and seawater decontaminations in Fukushima gave satisfactory results, demonstrating high capabilities of CNF/PB for practical applications. PMID:27845441

  8. Biosensor based on Prussian blue nanocubes/reduced graphene oxide nanocomposite for detection of organophosphorus pesticides

    SciTech Connect

    Zhang, Lin; Zhang, Aidong; Du, Dan; Lin, Yuehe

    2012-07-13

    We demonstrate a facile procedure to efficiently prepare Prussian blue nanocubes/reduced graphene oxide (PBNCs/rGO) nanocomposite by directly mixing Fe3+ and [Fe(CN)6]3 in the presence of GO in polyethyleneimine aqueous solution, resulting in a novel acetylcholinesterase (AChE) biosensor for detection of organophosphorus pesticides (OPs). The obtained nanocomposite was characterized by X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and energy dispersive X-ray (EDX) microanalysis. It was clearly observed that the nanosheet has been decorated with cubic PB nanoparticles and nearly all the nanoparticles are distributed uniformly only on the surface of the reduced GO. No isolated PB nanoparticles were observed, indicating the strong interaction between PB nanocubes and the reduced GO and the formation of PBNCs/rGO nanocomposite. The obtained PBNCs/rGO based AChE biosensor make the peak potential shift negatively to 220 mV. The AChE biosensor shows rapid response and high sensitivity for detection of monocrotophos. These results suggest that the PBNCs/rGO hybrids nanocomposite exhibited high electrocatalytic activity towards the oxidation of thiocholine, which lead to the sensitive detection of OP pesticides.

  9. Magnetic Prussian blue nanoparticles for targeted photothermal therapy under magnetic resonance imaging guidance.

    PubMed

    Fu, Guanglei; Liu, Wei; Li, Yanyan; Jin, Yushen; Jiang, Lingdong; Liang, Xiaolong; Feng, Shanshan; Dai, Zhifei

    2014-09-17

    This paper reported a core-shell nanotheranostic agent by growing Prussian blue (PB) nanoshells of 3-6 nm around superparamagnetic Fe3O4 nanocores for targeted photothermal therapy of cancer under magnetic resonance imaging (MRI) guidance. Both in vitro and in vivo experiments proved that the Fe3O4@PB core-shell nanoparticles showed significant contrast enhancement for T2-weighted MRI with the relaxivity value of 58.9 mM(-1)·s(-1). Simultaneously, the composite nanoparticles exhibited a high photothermal effect under irradiation of a near-infrared laser due to the strong absorption of PB nanoshells, which led to more than 80% death of HeLa cells with only 0.016 mg·mL(-1) of the nanoparticles with the aid of the magnetic targeting effect. Using tumor-bearing nude mice as the model, the near-infrared laser light ablated the tumor effectively in the presence of the Fe3O4@PB nanoparticles and the tumor growth inhibition was evaluated to be 87.2%. Capabilities of MRI, magnetic targeting, and photothermal therapy were thus integrated into a single agent to allow efficient MRI-guided targeted photothermal therapy. Most importantly, both PB and Fe3O4 nanoparticles were already clinically approved drugs, so the Fe3O4@PB nanoparticles as a theranostic nanomedicine would be particularly promising for clinical applications in the human body due to the reliable biosafety.

  10. Self-powered sensing platform equipped with Prussian blue electrochromic display driven by photoelectrochemical cell.

    PubMed

    Wang, Yanhu; Gao, Chaomin; Ge, Shenguang; Zhang, Lina; Yu, Jinghua; Yan, Mei

    2017-03-15

    By incorporating the Prussian Blue (PB) electrochromic display as cathode, a solar-driven photoelectrochemical (PEC) cell was constructed through combining sandwich-structured graphite-like carbon nitride (g-C3N4)-Au-branched-titanium dioxide (B-TiO2) nanorods as photoanode for self-powered hydrogen peroxide (H2O2) sensing, which exhibits both direct photoelectrochemical and electrochromic response. The gold nanoparticles (Au NPs) sandwiched between the B-TiO2 nanorods and the g-C3N4 layer served as electron relay as well as plasmonic photosensitizer to enhance the solar-to-chemical energy conversion efficiency. Owing to the effective disproportionation of H2O2 and specific recognition of mannose on cell surface, concanavalin-A conjugated porous AuPd alloy nanoparticles were introduced as the catalytically active nanolabels promoting generation of hydroxyl radicals (·OH). Based on the cleavage of DNA with the participation of ·OH radicals generated by the decomposition of H2O2 under the catalysis of AuPd alloy result in the disassembly of cancer cells to achieve further signal enhancement. The multiple-signal-output sensing response not only provides a promising strategy for different analytical purposes based on novel stimuli-responsive materials, but also enhances the reliability in the analyte detection.

  11. Possible role of Prussian blue nanoparticles in chemical evolution: interaction with ribose nucleotides

    NASA Astrophysics Data System (ADS)

    Sharma, Rachana; Iqubal, Md. Asif; Kamaluddin

    2016-01-01

    Ribonucleotides (RMPs) are the building blocks of genetic material consisting of a sugar group, a phosphate group and a nucleobase. Prussian blue (PB) is an ancient compound which is supposed to have formed under the conditions of primitive Earth. The interaction between nucleotides and mineral surfaces is of primary importance in the context of prebiotic chemistry. In the present work, the adsorption of RMPs on PB has been studied in the concentration range 0.4 × 10-4-3.0 × 10-4 M of RMPs at pH 7.5, T = 27°C and found to be 53.1, 41.7, 25.8 and 24.0% for adenosine 5'-monophosphate (5'-AMP), guanosine 5'-monophosphate, cytidine 5'-monophosphate and uridine 5'-monophosphate, respectively. Optimum conditions for the adsorption were studied as a function of concentration, time, amount of adsorbent and pH and data obtained were found to fit the Langmuir adsorption isotherm. Langmuir constants (K L and X m ) values were calculated. Fourier transform infrared spectroscopy, Raman spectroscopy, field-emission scanning electron microscopy and X-ray diffractometry techniques were used to investigate the interaction of RMPs on PB surface. Adsorption kinetics of 5'-AMP on PB has been found to be pseudo-second order. Results obtained from this study should prove valuable for a better understanding of the mechanism of RMP-PB interaction.

  12. Adsorption and desorption behaviors of cesium on rayon fibers coated with chitosan immobilized with Prussian blue.

    PubMed

    Dechojarassri, Duangkamol; Asaina, Shohei; Omote, Sahori; Nishida, Kensuke; Furuike, Tetsuya; Tamura, Hiroshi

    2017-03-15

    Rayon fiber coated with chitosan (CTS) that contained immobilized Prussian blue (KFe) (KFe/CTS/rayon) were investigated for the removal of cesium ion (Cs(+)) from contaminated water. The morphology and mechanical strength of the fibers were observed using scanning electron microscopy (SEM) and a universal testing machine, respectively. The Cs(+) concentration was determined by inductively coupled plasma-atomic emission spectroscopy. SEM images revealed that the surface of the KFe/CTS/rayon fiber showed the most roughness. It was found that Cs(+) was absorbed from the water by the KFe on the fibers in a molar ratio of 1:1 (Cs(+):KFe). After treating the KFe/CTS/rayon fiber with 1% HNO3 for 3h, 48.8% Cs(+) desorption was observed. Woven fibers were interlaced with either 2 or 4 lines of the KFe/CTS/rayon fiber from 16 bobbins. The tensile strengths of those fibers were 19.06 and 14.25MPa, respectively. When silver cotton was used as the core axis of the woven fiber, the tensile strength of the fibers interlaced with 2 and 4 lines increased to 27.18 and 25.17MPa, respectively. Moreover, the results of hot tests using radioactive Cs(+) showed that the woven KFe/CTS/rayon fibers could absorb up to 1000Bqg(-1) from an initial concentration of 8000Bqkg(-1).

  13. Prussian blue nanoparticle-based photothermal therapy combined with checkpoint inhibition for photothermal immunotherapy of neuroblastoma.

    PubMed

    Cano-Mejia, Juliana; Burga, Rachel A; Sweeney, Elizabeth E; Fisher, John P; Bollard, Catherine M; Sandler, Anthony D; Cruz, Conrad Russell Y; Fernandes, Rohan

    2017-02-01

    We describe "photothermal immunotherapy," which combines Prussian blue nanoparticle (PBNP)-based photothermal therapy (PTT) with anti-CTLA-4 checkpoint inhibition for treating neuroblastoma, a common, hard-to-treat pediatric cancer. PBNPs exhibit pH-dependent stability, which makes them suitable for intratumorally-administered PTT. PBNP-based PTT is able to lower tumor burden and prime an immune response, specifically an increased infiltration of lymphocytes and T cells to the tumor area, which is complemented by the antitumor effects of anti-CTLA-4 immunotherapy, providing a more durable treatment against neuroblastoma in an animal model. We observe 55.5% survival in photothermal immunotherapy-treated mice at 100days compared to 12.5%, 0%, 0%, and 0% survival in mice receiving: anti-CTLA-4 alone, PBNPs alone, PTT alone, and no treatment, respectively. Additionally, long-term surviving, photothermal immunotherapy-treated mice exhibit protection against neuroblastoma rechallenge, suggesting the development of immunity against these tumors. Our findings suggest the potential of photothermal immunotherapy in improving treatments for neuroblastoma.

  14. Prussian blue nanoparticles as peroxidase mimetics for sensitive colorimetric detection of hydrogen peroxide and glucose.

    PubMed

    Zhang, Weimin; Ma, Diao; Du, Jianxiu

    2014-03-01

    Prussian blue nanoparticles (PB NPs) exhibits an intrinsic peroxidase-like catalytic activity towards the hydrogen peroxide (H2O2)-mediated oxidation of classical peroxidase substrate 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt to produce a colored product. The catalysis follows Michaelis-Menen kinetics and shows strong affinity for H2O2. Using PB NPs as a peroxidase mimetics, a colorimetric method was developed for the detection of 0.05-50.0 μM H2O2, with a detection limit of 0.031 μM. When the catalytic reaction of PB NPs was coupled with the reaction of glucose oxidation catalyzed by glucose oxidase, a sensitive and selective colorimetric method for the detection of glucose was realized. The limit of detection for glucose was determined to be as low as 0.03 μM and the linear range was from 0.1 μM to 50.0 μM. The method was successfully applied to the determination of glucose in human serum. Compared with other nanomaterials-based peroxidase mimetics, PB NPs provides 10-100 times higher sensitivity toward the detection of H2O2 and glucose. The detection platform developed showed great potential applications in varieties of physiological importance substances when merged with appropriate H2O2-producing oxidases.

  15. Cellulose nanofiber backboned Prussian blue nanoparticles as powerful adsorbents for the selective elimination of radioactive cesium

    NASA Astrophysics Data System (ADS)

    Vipin, Adavan Kiliyankil; Fugetsu, Bunshi; Sakata, Ichiro; Isogai, Akira; Endo, Morinobu; Li, Mingda; Dresselhaus, Mildred S.

    2016-11-01

    On 11 March 2011, the day of the unforgettable disaster of the 9 magnitude Tohoku earthquake and quickly followed by the devastating Tsunami, a damageable amount of radionuclides had dispersed from the Fukushima Daiichi’s damaged nuclear reactors. Decontamination of the dispersed radionuclides from seawater and soil, due to the huge amounts of coexisting ions with competitive functionalities, has been the topmost difficulty. Ferric hexacyanoferrate, also known as Prussian blue (PB), has been the most powerful material for selectively trapping the radioactive cesium ions; its high tendency to form stable colloids in water, however, has made PB to be impossible for the open-field radioactive cesium decontamination applications. A nano/nano combinatorial approach, as is described in this study, has provided an ultimate solution to this intrinsic colloid formation difficulty of PB. Cellulose nanofibers (CNF) were used to immobilize PB via the creation of CNF-backboned PB. The CNF-backboned PB (CNF/PB) was found to be highly tolerant to water and moreover, it gave a 139 mg/g capability and a million (106) order of magnitude distribution coefficient (Kd) for absorbing of the radioactive cesium ion. Field studies on soil and seawater decontaminations in Fukushima gave satisfactory results, demonstrating high capabilities of CNF/PB for practical applications.

  16. Prussian blue caged in alginate/calcium beads as adsorbents for removal of cesium ions from contaminated water.

    PubMed

    Vipin, Adavan Kiliyankil; Hu, Baiyang; Fugetsu, Bunshi

    2013-08-15

    Prussian blue encapsulated in alginate beads reinforced with highly dispersed carbon nanotubes were prepared for the safe removal of cesium ions from aqueous solutions. Equilibrium and kinetic studies were conducted using different models and the goodness of mathematical fitting of the experimental data on the adsorption isotherms was in the order Langmuir>Freundlich, and that of the kinetic models were in the order of pseudo second order>pseudo first order. Fixed bed adsorption column analysis indicated that the beads can be used for large scale treatment of cesium contaminated water.

  17. Transient absorption studies of vibrational relaxation and photophysics of Prussian blue and ruthenium purple nanoparticles

    NASA Astrophysics Data System (ADS)

    Weidinger, D.; Brown, D. J.; Owrutsky, J. C.

    2011-03-01

    Transient infrared and visible absorption studies have been used to characterize vibrational and electronic dynamics of Prussian blue (PB) and ruthenium purple (RP) nanoparticles produced and characterized in AOT reverse micelles. Studies include excitation and probing with both infrared (near 2000 cm-1) and visible (800 nm) pulses. From IR pump-IR probe measurements of the CN stretching bands, vibrational population lifetimes are determined to be 32 ± 4 ps for PB and 44 ± 14 ps for RP. These times are longer than those for ferrocyanide (4 ps) and ruthenocyanide (4 ps) in normal water and are closer to the times for these species in heavy water (25-30 ps) and for ferrocyanide in formamide (43 ps). The PB and RP lifetimes are also longer than those (<15 ps) previously measured for CN stretching bands following intervalence excitation and back-electron transfer (BET) for dinuclear mixed-valence compounds containing Fe, Ru, and Os in heavy water and formamide [A. V. Tivansky, C. F. Wang, and G. C. Walker, J. Phys. Chem. A 107, 9051 (2003)]. In 800 nm pump-IR probe experiments on RP and PB, transient IR spectra and decay curves are similar to those with IR excitation; a ground state bleach and a red shifted (by ˜40 cm-1) excited state decay are observed. These results for the visible pumping are consistent with rapid (<1 ps) BET resulting in population in the ground electronic state with vibrational excitation in the CN mode. In addition, transient absorption studies were performed for PB and RP probing with visible light using both visible and IR excitation. The early time response for the 800 nm pump-800 nm probe of PB exhibits an instrument-limited, subpicosecond bleach followed by an absorption, which is consistent with the previously reported results [D. C. Arnett, P. Vohringer, and N. F. Scherer, J. Am. Chem. Soc. 117, 12262 (1995)]. The absorption exhibits a biexponential decay with decay times of 9 and 185 ps, which could have been attributed to the CN band

  18. In vivo binding of radiocesium by two forms of Prussian blue and by ammonium iron hexacyanoferrate (II).

    PubMed

    Dresow, B; Nielsen, P; Fischer, R; Pfau, A A; Heinrich, H H

    1993-01-01

    The effect of two forms of Prussian blue, soluble K3 Fe[Fe(CN)6] and insoluble Fe4[Fe(CN)6]3, and of ammonium iron hexacyanoferrate (II) (NH4Fe[Fe(CN)6] on intestinal radiocesium absorption was investigated in rats, pigs, and humans. In rats 5 mg of antidote administered 2 min before 134Cs tracer reduced radiocesium absorption to 2.4-6.3% of the oral dose. In pigs fed with Chernobyl-contaminated whey under normal feeding conditions for a 27 day period, radiocesium activity concentration was reduced from 360 Bq/kg in control animals to 10-30 Bq/kg by 5 g antidote/d. In man 1 g of oral Prussian blue diminished the cesium absorption from a 134Cs-labelled test meal to 5.6-6.4% of the controls. The inhibitory effects of colloidally soluble K3 Fe[Fe(CN)6] and of (NH4Fe[Fe(CN)6] were similar with slightly less inhibition by the insoluble Fe4[Fe(CN)6]3.

  19. Synthesis and fading of eighteenth-century Prussian blue pigments: a combined study by spectroscopic and diffractive techniques using laboratory and synchrotron radiation sources.

    PubMed

    Samain, Louise; Grandjean, Fernande; Long, Gary J; Martinetto, Pauline; Bordet, Pierre; Sanyova, Jana; Strivay, David

    2013-05-01

    Prussian blue, a hydrated iron(III) hexacyanoferrate(II) complex, is a synthetic pigment discovered in Berlin in 1704. Because of both its highly intense color and its low cost, Prussian blue was widely used as a pigment in paintings until the 1970s. The early preparative methods were rapidly recognized as a contributory factor in the fading of the pigment, a fading already known by the mid-eighteenth century. Herein two typical eighteenth-century empirical recipes have been reproduced and the resulting pigment analyzed to better understand the reasons for this fading. X-ray absorption and Mössbauer spectroscopy indicated that the early syntheses lead to Prussian blue together with variable amounts of an undesirable iron(III) product. Pair distribution functional analysis confirmed the presence of nanocrystalline ferrihydrite, Fe10O14(OH)2, and also identified the presence of alumina hydrate, Al10O14(OH)2, with a particle size of ∼15 Å. Paint layers prepared from these pigments subjected to accelerated light exposure showed a tendency to turn green, a tendency that was often reported in eighteenth- and nineteenth-century books. The presence of particles of hydrous iron(III) oxides was also observed in a genuine eighteenth-century Prussian blue sample obtained from a polychrome sculpture.

  20. Thermally activated charge transfer in a Prussian blue derivative probed by resonant inelastic x-ray scattering

    NASA Astrophysics Data System (ADS)

    Jarrige, I.; Cai, Y. Q.; Ishii, H.; Hiraoka, N.; Bleuzen, A.

    2008-08-01

    Charge-transfer excitation is at the source of the photoinduced magnetism observed in several Prussian blue molecule-based magnets. Using resonant inelastic x-ray scattering and x-ray absorption spectroscopy, we probe directly the thermally activated charge transfer in a photomagnetic Fe-Co cyanide, Cs0.7Co4[Fe(CN)6]2.9[◻]1.1.16H2O, where [◻] represents [Fe(CN)6] vacancies. The temperature dependence of both Co and Fe valence ratios is estimated for the first time in one cooling run, thus yielding a more complete picture of the temperature-induced cooperative electronic modifications. This novel approach, benefiting from relatively short acquisition times, opens the possibility for realtime characterization of the photoinduced magnetism in molecule-based magnets.

  1. Development of a Hydrogen Peroxide Sensor Based on Screen-Printed Electrodes Modified with Inkjet-Printed Prussian Blue Nanoparticles

    PubMed Central

    Cinti, Stefano; Arduini, Fabiana; Moscone, Danila; Palleschi, Giuseppe; Killard, Anthony J.

    2014-01-01

    A sensor for the simple and sensitive measurement of hydrogen peroxide has been developed which is based on screen printed electrodes (SPEs) modified with Prussian blue nanoparticles (PBNPs) deposited using piezoelectric inkjet printing. PBNP-modified SPEs were characterized using physical and electrochemical techniques to optimize the PBNP layer thickness and electroanalytical conditions for optimum measurement of hydrogen peroxide. Sensor optimization resulted in a limit of detection of 2 × 10−7 M, a linear range from 0 to 4.5 mM and a sensitivity of 762 μA·mM−1·cm−2 which was achieved using 20 layers of printed PBNPs. Sensors also demonstrated excellent reproducibility (<5% rsd). PMID:25093348

  2. Porous three-dimensional graphene foam/Prussian blue composite for efficient removal of radioactive 137Cs

    PubMed Central

    Jang, Sung-Chan; Haldorai, Yuvaraj; Lee, Go-Woon; Hwang, Seung-Kyu; Han, Young-Kyu; Roh, Changhyun; Huh, Yun Suk

    2015-01-01

    In this study, a simple one-step hydrothermal reaction is developed to prepare composite based on Prussian blue (PB)/reduced graphene oxide foam (RGOF) for efficient removal of radioactive cesium (137Cs) from contaminated water. Scanning electron microscopy and transmission electron microscopy show that cubic PB nanoparticles are decorated on the RGO surface. Owing to the combined benefits of RGOF and PB, the composite shows excellent removal efficiency (99.5%) of 137Cs from the contaminated water. The maximum adsorption capacity is calculated to be 18.67 mg/g. An adsorption isotherm fit-well the Langmuir model with a linear regression correlation value of 0.97. This type of composite is believed to hold great promise for the clean-up of 137Cs from contaminated water around nuclear plants and/or after nuclear accidents. PMID:26670798

  3. A novel capillary electrophoresis microchip with amperometric detection using a Prussian blue-modified indium tin oxide electrode

    NASA Astrophysics Data System (ADS)

    Kim, Ju-Ho; Kang, C. J.; Kim, Yong-Sang

    2005-03-01

    A novel approach to construct a disposable capillary electrophoresis microchip is proposed. The electrocatalytic oxidation of dopamine at a Prussian blue (PB)-modified indium tin oxide (ITO) electrode was described and the amperometric detection of dopamine was then investigated. The PB film on ITO electrode was electrodeposited using FeCl3 and K3Fe(CN)6 mixed solution. Our results indicated that PB film was uniform, smooth, and defect-free. The CE-chip has been tested successfully by detecting dopamine and catechol within a very short time of around 80 sec using an electric field of 60 V/cm. The results also showed that dopamine and catechol mixtures were separated efficiently and rapidly. The microsystems gave a very good reproducibility for peak height and separation time. This microchip is cost effective and adequate for a disposable sensor.

  4. Porous three-dimensional graphene foam/Prussian blue composite for efficient removal of radioactive (137)Cs.

    PubMed

    Jang, Sung-Chan; Haldorai, Yuvaraj; Lee, Go-Woon; Hwang, Seung-Kyu; Han, Young-Kyu; Roh, Changhyun; Huh, Yun Suk

    2015-12-16

    In this study, a simple one-step hydrothermal reaction is developed to prepare composite based on Prussian blue (PB)/reduced graphene oxide foam (RGOF) for efficient removal of radioactive cesium ((137)Cs) from contaminated water. Scanning electron microscopy and transmission electron microscopy show that cubic PB nanoparticles are decorated on the RGO surface. Owing to the combined benefits of RGOF and PB, the composite shows excellent removal efficiency (99.5%) of (137)Cs from the contaminated water. The maximum adsorption capacity is calculated to be 18.67 mg/g. An adsorption isotherm fit-well the Langmuir model with a linear regression correlation value of 0.97. This type of composite is believed to hold great promise for the clean-up of (137)Cs from contaminated water around nuclear plants and/or after nuclear accidents.

  5. Magnetic properties of RbjCo4[Fe(CN)6]k.nH2O Prussian blue nanoparticles

    NASA Astrophysics Data System (ADS)

    Anderson, N. E.; Long, J.

    2005-11-01

    Magneto-optically active Prussian blue materials are of considerable interest because of their many possible applications.ootnotetextJ.-H. Park, E. Cizm'ar, M. W. Meisel, Y. D. Huh, F. Frye, S. Lane, and D. R. Talham, Appl. Phys. Lett. 85, 3797 (2004). Nanoparticles of RbjCo4[Fe(CN)6]k.nH2O have been synthesized, and TEM images indicate that clusters of 5 nm particles were obtained. Futhermore, the particles appear to show weak photo-induced effects similar to those reported in bulk materials. Here, we present preliminary data to illustrate the magnetic characteristics of these new materials. J. Long was a NSF-REU participant (NSF CHE-0353828).

  6. Electrocatalytic properties of prussian blue nanoparticles supported on poly(m-aminobenzenesulphonic acid)-functionalised single-walled carbon nanotubes towards the detection of dopamine.

    PubMed

    Adekunle, Abolanle S; Farah, Abdullahi M; Pillay, Jeseelan; Ozoemena, Kenneth I; Mamba, Bhekie B; Agboola, Bolade O

    2012-06-15

    Edged plane pyrolytic graphite electrode (EPPGE) was modified with and without Prussian blue (PB) nanoparticles and polyaminobenzene sulphonated single-walled carbon nanotubes (SWCNTPABS) using the chemical deposition method. The electrodes were characterised using microscopy, spectroscopy and electrochemical techniques. Results showed that edged plane pyrolytic graphite-single-walled carbon nanotubes-prussian blue (EPPGE-SWCNT-PB) electrode gave the best dopamine (DA) current response, which increases with increasing PB layers. The catalytic rate constant of 1.69 × 10(5)mol(-1)cm(3)s(-1), Tafel value of 112 mV dec(-1), and limit of detection of DA (2.8 nM) were obtained. Dopamine could be simultaneously detected with ascorbic acid. The electrode was found to be electrochemically stable, reusable and can be used for the analysis of DA in real drug samples.

  7. Enzyme-triggered tyramine-enzyme repeats on prussian blue-gold hybrid nanostructures for highly sensitive electrochemical immunoassay of tissue polypeptide antigen.

    PubMed

    Xu, Tisen; Zhang, Haiying; Li, Xuegui; Xie, Zhaohui; Li, Xiangyong

    2015-11-15

    A novel sandwich-type electrochemical immunoassay with sensitivity enhancement was developed for quantitative detection of tissue polypeptide antigen (TPA) by coupling with target-induced tyramine signal amplification on prussian blue-gold hybrid nanostructures. The immunosensor was prepared through immobilizing anti-TPA capture antibody on a cleaned screen-printed carbon electrode (SPCE). Prussian blue-gold hybrid nanostructures (PBGNS) labeled with horseradish peroxidase (HRP) and detection antibody were utilized as the signal-transduction tags. Upon target TPA introduction, the sandwiched immunocomplex was formed between capture antibody and detection antibody on the electrode. The carried HRP could trigger the formation of tyramine-HRP repeats on the PBGNS in the presence of H2O2. Using the doped prussian blue as the electron mediator, the conjugated HRP could catalyze the reduction of H2O2. Under the optimal conditions, the catalytic currents increased with the increasing target TPA in the dynamic range from 1.0 pg mL(-1) to 100 ng mL(-1) with a detection limit of 0.3 pg mL(-1). The reproducibility and specificity of the electrochemical immunoassay were acceptable. In addition, the contents of target TPA in nine human serum specimens were evaluated by using the developed electrochemical immunosensor, and the obtained results correlated well with those from commercially enzyme-linked immunosorbent assay (ELISA) method with a correlation coefficient of 0.9975.

  8. Amperometric immunosensor based on multiwalled carbon nanotubes/Prussian blue/nanogold-modified electrode for determination of α-fetoprotein.

    PubMed

    Jiang, Wen; Yuan, Ruo; Chai, Ya-Qin; Yin, Bing

    2010-12-01

    In this article, a conspicuously simple and highly sensitive amperometric immunosensor based on the sequential electrodeposition of Prussian blue (PB) and gold nanoparticles (GNPs) on multiwalled carbon nanotube (MWCNT)-modified glassy carbon electrode (GCE) surface is proposed for the detection of α-fetoprotein (AFP). By comparison with PB, the MWCNT/PB composite film had been proven to show much better electrochemical stability and a larger response current. The electrodeposited GNP film can be used not only to immobilize biomolecules but also to avoid the leakage of PB and to prevent shedding of MWCNT/PB composite film from the electrode surface. The performance and factors influencing the performance of the immunosensor were investigated. Under optimal experimental conditions, the proposed immunosensor for AFP was observed with an ultralow limit of detection (LOD) equal to 3 pg/ml (at 3δ), and the linear working range spanned the concentrations of AFP from 0.01 to 300 ng/ml. Moreover, the immunosensor, as well as a commercially available kit, was examined for use in the determination of AFP in real human serum specimens. More significant, the assay mentioned here is simpler than the traditional enzyme-linked immunosorbent assay (ELISA), and an excellent correlation of levels of AFP measured was obtained, indicating that the developed immunoassay could be a promising alternative approach for detection of AFP and other tumor markers in the clinical diagnosis.

  9. Application of Prussian Blue electrodes for amperometric detection of free chlorine in water samples using Flow Injection Analysis.

    PubMed

    Salazar, Pedro; Martín, Miriam; González-Mora, José Luis; González-Elipe, Agustín R

    2016-01-01

    The performance for free chlorine detection of surfactant-modified Prussian Blue screen printed carbon electrodes (SPCEs/PB-BZT) have been assessed by cyclic voltammetry and constant potential amperometry. The characterization of SPCEs/PB-BZT by X-ray photoemission, Raman and infrared spectroscopies confirmed the correct electrodeposition of the surfactant-modified PB film. These electrodes were incorporated in a Flow Injection device and the optimal working conditions determined as a function of experimental variables such as detection potential, electrolyte concentration or flow-rate. The sensor presented a linear response in the range 0-3 ppm free chlorine, with a sensitivity of 16.2 μA ppm(-1) cm(-2). The limit of detection (LOD) (S/N=3.3) and the limit of quantification (S/N=10) amounted to 8.25 and 24.6 ppb, respectively, adequate for controlling tap and drinking waters. To demonstrate the feasibility of using this free chlorine sensor for real applications possible interferences such as nitrate, nitrite and sulfate ions were successfully tested and discarded. Real free chlorine analysis was carried out in spiked tap water samples and commercial bleaches.

  10. Hydrogen peroxide detection in wet air with a Prussian Blue based solid salt bridged three electrode system.

    PubMed

    Komkova, Maria A; Karyakina, Elena E; Marken, Frank; Karyakin, Arkady A

    2013-03-05

    We report on a novel electroanalytical system for hydrogen peroxide (H2O2) detection in humidity or droplets of aerosol, formed by air bubbling through a washing chamber; the resulting flow mimics the exhaled human breath. The system is based on a planar three-electrode structure (with a Prussian Blue based H2O2 transducer modified working electrode) bridged by a solid salt-saturated filament material (filter paper, cotton textile). Respective to the hydrogen peroxide content in the washing valve, the response of the aerosol-sensing system is linear in the concentration range of 0.1-10 μM, which overlaps the generally accepted H2O2 content in exhaled breath condensate (EBC), with the sensitivity of 8 A M(-1) cm(-2). The response to the upper limit of the calibration range is stable for more than 50 injection cycles recorded within 3 days. Both the stability and the suitable calibration range allow one to consider the reported aerosol-sensing system as a prototype for a simple (avoiding intermediate EBC collection) noninvasive diagnostic tool for pulmonary patients.

  11. One-Pot Hydrothermal Synthesis of Magnetite Prussian Blue Nano-Composites and Their Application to Fabricate Glucose Biosensor

    PubMed Central

    Jomma, Ezzaldeen Younes; Ding, Shou-Nian

    2016-01-01

    In this work, we presented a simple method to synthesize magnetite Prussian blue nano-composites (Fe3O4-PB) through one-pot hydrothermal process. Subsequently, the obtained nano-composites were used to fabricate a facile and effective glucose biosensor. The obtained nanoparticles were characterized using transmission electron microscopy, scanning electron microscopy, Fourier-transform infrared spectroscopy, UV-vis absorbance spectroscopy, cyclic voltammetry and chronoamperometry. The resultant Fe3O4-PB nanocomposites have magnetic properties which could easily controlled by an external magnetic field and the electro-catalysis of hydrogen peroxide. Thus, a glucose biosensor based on Fe3O4-PB was successfully fabricated. The biosensor showed super-electrochemical properties toward glucose detection exhibiting fast response time within 3 to 4 s, low detection limit of 0.5 µM and wide linear range from 5 µM to 1.2 mM with sensitivity of 32 µA∙mM−1∙cm−2 and good long-term stability. PMID:26901204

  12. Spontaneous Deposition of Prussian Blue on Multi-Walled Carbon Nanotubes and the Application in an Amperometric Biosensor

    PubMed Central

    Yao, Yanli; Bai, Xiaoyun; Shiu, Kwok-Keung

    2012-01-01

    A simple method has been developed for the spontaneous deposition of Prussian blue (PB) particles from a solution containing only ferricyanide ions onto conducting substrates such as indium tin oxide glass, glassy carbon disk and carbon nanotube (CNT) materials. Formation of PB deposits was confirmed by ultraviolet-visible absorption spectrometry and electrochemical techniques. The surface morphology of the PB particles deposited on the substrates was examined by atomic force microscopy and scanning electron microscopy. CNT/PB composite modified glassy carbon electrodes exhibited an electrocatalytic property for hydrogen peroxide reduction. These modified electrodes exhibited a high sensitivity for electrocatalytic reduction of hydrogen peroxide at −0.05 V (vs. Ag|AgCl), probably due to the synergistic effect of CNT with PB. Then, CNT/PB modified electrodes were further developed as amperometric glucose biosensors. These biosensors offered a linear response to glucose concentration from 0.1 to 0.9 mM with good selectivity, high sensitivity of 0.102 A M−1 cm−2 and short response time (within 2 s) at a negative operation potential of −0.05 V (vs. Ag|AgCl). The detection limit was estimated to be 0.01 mM at a signal-to-noise ratio of 3. PMID:28348317

  13. Novel polystyrene microspheres functionalized by imidazolium and the electrocatalytic activity towards H2O2 of its Prussian blue composite

    NASA Astrophysics Data System (ADS)

    Mao, Hui; Song, Jinling; Zhang, Qian; Liu, Daliang; Gong, Naiqi; Li, Ying; Wu, Qiong; Verpoort, Francis; Song, Xi-Ming

    2013-05-01

    Copolymerization of styrene (St) and 1-vinyl-3-ethylimidazolium bromide (VEIB), novel poly(St-co-VEIB) microspheres were generated. Owing to the presence of imidazolium groups, such microspheres having an average diameter of 125 nm, behave electropositively when dispersed in aqueous solution. Furthermore, due to the presence of imidazolium groups, having a capacity of ion-exchange and weak reducibility on the surface of the PS microspheres, [Fe(CN)6]3- was absorbed on the surface of poly(St-co-VEIB) microspheres, and simultaneously, Fe3+ was reduced to Fe2+. Thus, in situ growth of Prussian blue (PB) nanoparticles could occur on the surface of poly(St-co-VEIB) microspheres without the addition of any other reducing agent. This methodology, utilizing the ion-exchange and weak reducibility properties of the imidazolium groups on the surface of micro-/nanostructures is a novel general method for assembling hierarchical nanostructured materials. Finally, the electrochemical property of the strawberry-like PS/PB composite microspheres was also investigated by applying a glassy carbon electrode. A good repeatability of the cyclic voltammetry responses, having a good linearity and sensitivity, for the electrocatalytic reduction of H2O2 was obtained.

  14. Anomalous non-Prussian blue structures and magnetic ordering of K(2)Mn(II)[Mn(II)(CN)(6)] and Rb(2)Mn(II)[Mn(II)(CN)(6)].

    PubMed

    Her, Jae-Hyuk; Stephens, Peter W; Kareis, Christopher M; Moore, Joshua G; Min, Kil Sik; Park, Jong-Won; Bali, Garima; Kennon, Bretni S; Miller, Joel S

    2010-02-15

    The reaction of Mn(II) and KCN in aqueous and non-aqueous media leads to the isolation of three-dimensional (3-D) Prussian blue analogues, K(2)Mn[Mn(CN)(6)] (1a-d, 1e, respectively). Use of RbCN forms Rb(2)Mn[Mn(CN)(6)] (2). 1 and 2 are isomorphic {monoclinic, P2(1)/n: 1 [a = 10.1786(1) A, b = 7.4124(1) A, c = 6.9758(1) A, beta = 90.206(1)(o)]; 2 [a = 10.4101(1) A, b = 7.4492(1) A, c = 7.2132(1) A, beta = 90.072(1)(o)]}, with a small monoclinic distortion from the face centered cubic (fcc) structure that is typical of Prussian blue structured materials that was previously reported for K(2)Mn[Mn(CN)(6)]. Most notably the average Mn-N-C angles are 148.8 degrees and 153.3 degrees for 1 and 2, respectively, which are significantly reduced from linearity. This is attributed to the ionic nature of high spin Mn(II) accommodating a reduced M-CN-M' angle and minimizing void space. Compounds 1a,b have a sharp, strong nu(OH) band at 3628 cm(-1), while 1e lacks a nu(OH) absorption. The nu(OH) absorption in 1a,b is attributed to surface water, as use of D(2)O shifts the nu(OH) absorption to 2677 cm(-1), and that 1a-e are isostructural. Also, fcc Prussian blue-structured Cs(2)Mn[Mn(CN)(6)] (3) has been structurally [Fm3m: a = 10.6061(1) A] and magnetically characterized. The magnetic ordering temperature, T(c), increases as K(+) (41 K) > Rb(+) (34.6 K) > Cs(+) (21 K) for A(2)Mn[Mn(CN)(6)] in accord with the increasing deviation for linearity of the Mn-N-C linkages [148.8 (K(+)) > 153.3 (Rb(+)) > 180 degrees (Cs(+))], decreasing Mn(II)...Mn(II) separations [5.09 (K(+)) < 5.19 (Rb(+)) < 5.30 A (Cs(+))], and decreasing size of the cation (increasing electrostatic interactions). Hence, the bent cyanide bridges play a crucial role in the superexchange mechanism by increasing the coupling via shorter Mn(II)...Mn(II) separations, and perhaps enhanced overlap. In addition, the temperature dependent magnetic behavior of K(4)[Mn(II)(CN)(6)].3H(2)O is reported.

  15. A Prussian blue/carbon dot nanocomposite as an efficient visible light active photocatalyst for C-H activation of amines.

    PubMed

    Maaoui, Houcem; Kumar, Pawan; Kumar, Anurag; Pan, Guo-Hui; Chtourou, Radouane; Szunerits, Sabine; Boukherroub, Rabah; Jain, Suman L

    2016-10-05

    A Prussian blue/carbon dot (PB/CD) nanocomposite was synthesised and used as a visible-light active photocatalyst for the oxidative cyanation of tertiary amines to α-aminonitriles by using NaCN/acetic acid as a cyanide source and H2O2 as an oxidant. The developed photocatalyst afforded high yields of products after 8 h of visible light irradiation at room temperature. The catalyst was recycled and reused several times without any significant loss in its activity.

  16. Surfactant-assisted fabrication of 3D Prussian blue-reduced graphene oxide hydrogel as a self-propelling motor for water treatment

    NASA Astrophysics Data System (ADS)

    Hao, Jinhui; Yang, Wenshu; Zhang, Zhe; Tang, Jilin

    2015-06-01

    Three-dimensional Prussian blue-reduced graphene oxide hydrogel was synthesized with the assistance of sodium dodecyl sulfate (SDS) through a facile hydrothermal method. The hydrogel exhibited strong mechanical properties and was successfully applied as a self-propelling motor for water treatment. During the self-propelling degradation process, SDS facilitated the rapid liberation of oxygen bubbles from the motor and the oxygen bubbles assisted the rapid diffusion of hydroxyl radicals. In addition, the well-defined structure increased the number of reaction sites and the synergy between reduced graphene oxide and Prussian blue, which accelerated the degradation efficiency. The self-propelling motor had an average velocity of 0.026 +/- 0.013 cm s-1 in 7.5% H2O2 and 0.069 +/- 0.032 cm s-1 in 22.5% H2O2. Moreover, the self-propelling motor maintained high degradation efficiency even after cycling for 9 times. These excellent properties make the self-propelling motor an ideal candidate for water treatment.Three-dimensional Prussian blue-reduced graphene oxide hydrogel was synthesized with the assistance of sodium dodecyl sulfate (SDS) through a facile hydrothermal method. The hydrogel exhibited strong mechanical properties and was successfully applied as a self-propelling motor for water treatment. During the self-propelling degradation process, SDS facilitated the rapid liberation of oxygen bubbles from the motor and the oxygen bubbles assisted the rapid diffusion of hydroxyl radicals. In addition, the well-defined structure increased the number of reaction sites and the synergy between reduced graphene oxide and Prussian blue, which accelerated the degradation efficiency. The self-propelling motor had an average velocity of 0.026 +/- 0.013 cm s-1 in 7.5% H2O2 and 0.069 +/- 0.032 cm s-1 in 22.5% H2O2. Moreover, the self-propelling motor maintained high degradation efficiency even after cycling for 9 times. These excellent properties make the self-propelling motor an

  17. Synthesis, structural elucidation and carbon dioxide adsorption on Zn (II) hexacyanoferrate (II) Prussian blue analogue

    NASA Astrophysics Data System (ADS)

    Roque-Malherbe, R.; Lugo, F.; Polanco, R.

    2016-11-01

    In the course of the last years hexacyanoferrates have been widely studied; even though, the adsorption properties of Zn (II) hexacyanoferrate(II) (labelled here Zn-HII) have not been thoroughly considered. In addition, soft porous crystals, i.e., adsorbents that display structural flexibility have been, as well, extensively studied, however this property has not been reported for Zn (II) hexacyanoferrate(II). In this regard, the key questions addressed here were the synthesis and structural characterization of Zn-HII together with the investigation of their low (up to 1 bar) and high pressure (up to 30 bar) adsorption properties, to found if these materials show structural flexibility. Then, to attain the anticipated goals, structural characterizations were made with: X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), diffuse reflectance infrared Fourier transform spectrometry (DRIFTS) and thermo-gravimetric analysis (TGA), simultaneously, with the investigation of the adsorption of carbon dioxide. As a result of the research process we concluded that the Zn-HII displayed Fm3 barm space group framework. Besides, the carbon dioxide adsorption investigation demonstrated the presence of the framework expansion effect together with an extremely high adsorption heat, properties that could be useful for the use of Zn(II) hexacyanoferrate(II) as an excellent adsorbent.

  18. Chitin-Prussian blue sponges for Cs(I) recovery: from synthesis to application in the treatment of accidental dumping of metal-bearing solutions.

    PubMed

    Vincent, C; Barré, Y; Vincent, T; Taulemesse, J-M; Robitzer, M; Guibal, E

    2015-04-28

    Prussian blue (i.e., iron[III] hexacyanoferrate[II], PB) has been synthesized by reaction of iron(III) chloride with potassium hexacyanoferrate and further immobilized in chitosan sponge (cellulose fibers were added in some samples to evaluate their impact on mechanical resistance). The composite was finally re-acetylated to produce a chitin-PB sponge. Experimental conditions such as the freezing temperature, the content of PB, the concentration of the biopolymer and the presence of cellulose fibers have been varied in order to evaluate their effect on the porous structure of the sponge, its water absorption properties and finally its use for cesium(I) recovery. The concept developed with this system consists in the absorption of contaminated water by the composite sponge, the in situ binding of target metal on Prussian blue load and the centrifugation of the material to remove treated water from soaked sponge. This material is supposed to be useful for the fast treatment of accidental dumping of Cs-contaminated water.

  19. LA-ICP-MS Allows Quantitative Microscopy of Europium-Doped Iron Oxide Nanoparticles and is a Possible Alternative to Ambiguous Prussian Blue Iron Staining.

    PubMed

    Scharlach, Constantin; Müller, Larissa; Wagner, Susanne; Kobayashi, Yuske; Kratz, Harald; Ebert, Monika; Jakubowski, Norbert; Schellenberger, Eyk

    2016-05-01

    The development of iron oxide nanoparticles for biomedical applications requires accurate histological evaluation. Prussian blue iron staining is widely used but may be unspecific when tissues contain substantial endogenous iron. Here we tested whether microscopy by laser ablation coupled to inductively coupled plasma mass spectrometry (LA-ICP-MS) is sensitive enough to analyze accumulation of very small iron oxide particles (VSOP) doped with europium in tissue sections. For synthesis of VSOP, a fraction of Fe3+ (5 wt%) was replaced by Eu3+, resulting in particles with 0.66 mol% europium relative to iron (Eu-VSOP) but with otherwise similar properties as VSOP. Eu-VSOP or VSOP was intravenously injected into ApoE-/- mice on Western cholesterol diet and accumulated in atherosclerotic plaques of these animals. Prussian blue staining was positive for ApoE-/- mice with particle injection but also for controls. LA-ICP-MS microscopy resulted in sensitive and specific detection of the europium of Eu-VSOP in liver and atherosclerotic plaques. Furthermore, calibration with Eu-VSOP allowed calculation of iron and particle concentrations in tissue sections. The combination of europium-doped iron oxide particles and LA-ICP-MS microscopy provides a new tool for specific and quantitative analysis of particle distribution at the tissue level and allows correlation with other elements such as endogenous iron.

  20. A high-sensitive and fast-fabricated glucose biosensor based on Prussian blue/topological insulator Bi2Se3 hybrid film.

    PubMed

    Wu, Shouguo; Liu, Gang; Li, Ping; Liu, Hao; Xu, Haihong

    2012-01-01

    A novel and fast-fabricated Prussian blue (PB)/topological insulator Bi(2)Se(3) hybrid film has been prepared by coelectrodeposition technique. Taking advantages of topological insulator in possessing exotic metallic surface states with bulk insulating gap, Prussian blue nanoparticles in the hybrid film have smaller size as well as more compact structure, showing excellent pH stability even in the alkalescent solution of pH 8.0. Based on the Laviron theory, the electron transfer rate constant of PB/Bi(2)Se(3) hybrid film modified electrode was calculated to be 4.05 ± 0.49 s(-1), a relatively big value which may be in favor of establishing a high-sensitive biosensor. An amperometric glucose biosensor was then fabricated by immobilizing glucose oxidase (GOD) on the hybrid film. Under the optimal conditions, a wide linear range extending over 3 orders of magnitude of glucose concentrations (1.0 × 10(-5)-1.1 × 10(-2)M) was obtained with a high sensitivity of 24.55 μA mM(-1) cm(-2). The detection limit was estimated for 3.8 μM defined from a signal/noise of 3. Furthermore, the resulting biosensor was applied to detect the blood sugar in human serum samples without any pretreatment, and the results were comparatively in agreement with the clinical assay.

  1. A choline oxidase amperometric bioassay for the detection of mustard agents based on screen-printed electrodes modified with Prussian Blue nanoparticles.

    PubMed

    Arduini, Fabiana; Scognamiglio, Viviana; Covaia, Corrado; Amine, Aziz; Moscone, Danila; Palleschi, Giuseppe

    2015-02-13

    In this work a novel bioassay for mustard agent detection was proposed. The bioassay is based on the capability of these compounds to inhibit the enzyme choline oxidase. The enzymatic activity, which is correlated to the mustard agents, was electrochemically monitored measuring the enzymatic product, hydrogen peroxide, by means of a screen-printed electrode modified with Prussian Blue nanoparticles. Prussian Blue nanoparticles are able to electrocatalyse the hydrogen peroxide concentration reduction at low applied potential (-50 mV vs. Ag/AgCl), thus allowing the detection of the mustard agents with no electrochemical interferences. The suitability of this novel bioassay was tested with the nitrogen mustard simulant bis(2-chloroethyl)amine and the sulfur mustard simulants 2-chloroethyl ethyl sulfide and 2-chloroethyl phenyl sulfide. The bioassay proposed in this work allowed the detection of mustard agent simulants with good sensitivity and fast response, which are excellent premises for the development of a miniaturised sensor well suited for an alarm system in case of terrorist attacks.

  2. One-pot green synthesis of Prussian blue nanocubes decorated reduced graphene oxide using mushroom extract for efficient 4-nitrophenol reduction.

    PubMed

    Chen, Ruixue; Zhang, Qiuping; Gu, Yue; Tang, Liu; Li, Cong; Zhang, Zhiquan

    2015-01-01

    One-pot green approach to the synthesis of Prussian blue nanocubes/reduced graphene oxide (PBNCs/RGO) nanocomposite had been attempted. It was based on the extract of mushroom with K3[Fe(CN)6] and graphene oxide (GO) as precursors, where the reduction of GO and the deposition of PBNCs occurred simultaneously. The obtained nanocomposite was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy and electrochemical techniques. With the introduction of β-cyclodextrin (β-CD), the β-CD/PBNCs/RGO system showed linear behavior in the range from 0.01 to 700 μM for 4-nitrophenol with a low detection limit of 2.34 nM (S/N=3).

  3. A 980nm driven photothermal ablation of virulent and antibiotic resistant Gram-positive and Gram-negative bacteria strains using Prussian blue nanoparticles.

    PubMed

    Maaoui, Houcem; Jijie, Roxana; Pan, Guo-Hui; Drider, Djamel; Caly, Delphine; Bouckaert, Julie; Dumitrascu, Nicoleta; Chtourou, Radouane; Szunerits, Sabine; Boukherroub, Rabah

    2016-10-15

    A 980nm laser-driven antimicrobial photothermal therapy using poly(vinylpyrrolidone) -coated Prussian Blue nanoparticles (PVP/PB NPs) is demonstrated. This approach allows an efficient eradication of a virulent strain of Gram-negative Escherichia coli (E. coli) associated with urinary tract infection as well as for the ablation of antibiotic resistant pathogens such as methicillin resistant Staphylococcus aureus (MRSA) and extended spectrum β-lactamase (ESBL) E. coli. Interestingly the 980nm irradiation exhibits minimal effect on mammalian cells up to a PVP/PB NPs concentration of 50μgmL(-1), while at this concentration bacteria are completely eradicated. This feature is certainly very promising for the selective targeting of bacteria over mammalian cells.

  4. Poly(vinyl alcohol) and alginate cross-linked matrix with immobilized Prussian blue and ion exchange resin for cesium removal from waters.

    PubMed

    Lai, Yu-Chen; Chang, Yin-Ru; Chen, Man-Li; Lo, Yu-Kuo; Lai, Juin-Yih; Lee, Duu-Jong

    2016-08-01

    Cesium (Cs) removal from contaminated water bodies is an emerging issue after the disaster at the Fukushima Daiichi Nuclear Power Plant. The Prussian blue (PB) is an effective Cs adsorbent but will release hexacyanoferrate fragments from the adsorbent matrix during adsorption. Alginate is an affordable biopolymer for PB particles immobilization. This study synthesized poly(vinyl alcohol) (PVA) and alginate cross-linked matrix for immobilization of PB nano-sized particles and a surface-modified styrene-ethyl styrene divinyl benzene resin and tested their swelling stability and Cs adsorption performance in fresh water and in seawater. The PVA-alginate granules have high structural stability in both fresh water and seawater, with the Cs adsorption capability higher for the former than the latter. The adopted resin effectively remove released PB fragments from the tested granules. The transport and reaction parameters for the granules and for the sand filter bed were estimated.

  5. Visible photoelectrochemical sensing platform by in situ generated CdS quantum dots decorated branched-TiO2 nanorods equipped with Prussian blue electrochromic display.

    PubMed

    Wang, Yanhu; Ge, Shenguang; Zhang, Lina; Yu, Jinghua; Yan, Mei; Huang, Jiadong

    2017-03-15

    In this study, based on in situ generation of CdS quantum dots (QDs) on the surface of branched TiO2 (B-TiO2) nanorods, an solar innovative photoelectrochemical (PEC) sensing platform was constructed for real-time, and sensitive detection of cellular H2S. Specifically, B-TiO2 nanorods arrays consisting of TiO2 nanorods directly grown on fluorine-doped tin oxide (FTO) further using TiCl3 mediated surface treatment of TiO2 nanorods are designed and fabricated as a new type of photoelectrode. CdS quantum dots (QDs) was formed on the surface of B-TiO2 nanorods arrays through the reaction between Cd(2+) and S(2-). And a significant enhancement in the photocurrent was obtained that ascribed to the formation of CdS-B-TiO2 heterostructures, thus leading to sensitive PEC recording of the H2S level in buffer and cellular environments. By using Prussian blue (PB) a electrochromic material to capture the photoelectron generated from the photoelectrode, a new visual system was proposed due to the formation of Prussian white (PW), which could be used to visualize the quantum photoelectric effect. This novel PEC sensing platform not only achieved satisfied analysis results toward S(2-), but also showed excellent sensitivity, selectivity, low cost, and portable features. The strategy through the in situ generation of semiconductor nanoparticles on the surface of wide band-gap semiconductor paves the way for the improvements of PEC analytical performance. Meanwhile, the quantitative read-out electrochromic display paves a facile avenue and initiates new opportunities for creation of cheap, miniaturization sensors for other relevant analytes.

  6. Periodic Mesoporous Organosilica Coated Prussian Blue for MR/PA Dual‐Modal Imaging‐Guided Photothermal‐Chemotherapy of Triple Negative Breast Cancer

    PubMed Central

    Tian, Wei; Su, Yunyan; Tian, Ying; Wang, Shouju; Su, Xiaodan; Liu, Ying; Zhang, Yunlei; Tang, Yuxia; Ni, Qianqian; Liu, Wenfei; Dang, Meng; Wang, Chunyan; Zhang, Junjie

    2016-01-01

    Complete eradication of highly aggressive triple negative breast cancer (TNBC) remains a notable challenge today. In this work, an imaging‐guided photothermal‐chemotherapy strategy for TNBC is developed for the first time based on a periodic mesoporous organosilica (PMO) coated Prussian blue (PB@PMO) nanoplatform. The PB@PMOs have organic‐inorganic hybrid frameworks, uniform diameter (125 nm), high surface area (866 m2 g−1), large pore size (3.2 nm), excellent photothermal conversion capability, high drug loading capacity (260 µg mg−1), and magnetic resonance (MR) and photoacoustic (PA) imaging abilities. The MR and PA properties of the PB@PMOs are helpful for imaging the tumor and showing the accumulation of the nanoplatform in the tumor region. The bioluminescence intensity and tumor volume of the MDA‐MB‐231‐Luc tumor‐bearing mouse model demonstrate that TNBC can be effectively inhibited by the combined photothermal‐chemotherapy than monotherapy strategy. Histopathological analysis further reveals that the combination therapy results in most extensive apoptotic and necrotic cells in the tumor without inducing obvious side effect to major organs. PMID:28331788

  7. 3D-Printed Fluidic Devices for Nanoparticle Preparation and Flow-Injection Amperometry Using Integrated Prussian Blue Nanoparticle-Modified Electrodes.

    PubMed

    Bishop, Gregory W; Satterwhite, Jennifer E; Bhakta, Snehasis; Kadimisetty, Karteek; Gillette, Kelsey M; Chen, Eric; Rusling, James F

    2015-01-01

    A consumer-grade fused filament fabrication (FFF) 3D printer was used to construct fluidic devices for nanoparticle preparation and electrochemical sensing. Devices were printed using poly(ethylene terephthalate) and featured threaded ports to connect polyetheretherketone (PEEK) tubing via printed fittings prepared from acrylonitrile butadiene styrene (ABS). These devices included channels designed to have 800 μm × 800 μm square cross sections and were semitransparent to allow visualization of the solution-filled channels. A 3D-printed device with a Y-shaped mixing channel was used to prepare Prussian blue nanoparticles (PBNPs) under flow rates of 100 to 2000 μL min(-1). PBNPs were then attached to gold electrodes for hydrogen peroxide sensing. 3D-printed devices used for electrochemical measurements featured threaded access ports into which a fitting equipped with reference, counter, and PBNP-modified working electrodes could be inserted. PBNP-modified electrodes enabled amperometric detection of H2O2 in the 3D-printed channel by flow-injection analysis, exhibiting a detection limit of 100 nM and linear response up to 20 μM. These experiments show that a consumer-grade FFF printer can be used to fabricate low-cost fluidic devices for applications similar to those that have been reported with more expensive 3D-printing methods.

  8. Polypyrrole and graphene quantum dots @ Prussian Blue hybrid film on graphite felt electrodes: Application for amperometric determination of l-cysteine.

    PubMed

    Wang, Lei; Tricard, Simon; Yue, Pengwei; Zhao, Jihua; Fang, Jian; Shen, Weiguo

    2016-03-15

    A novel polypyrrole (PPy) and graphene quantum dots (GQDs) @ Prussian Blue (PB) nanocomposite has been grafted on a graphite felt (GF) substrate (PPy/GQDs@PB/GF), and has been proven to be an efficient electrochemical sensor for the determination of l-cysteine (l-cys). GQDs, which were fabricated by carbonization of citric acid and adsorbed on GF surface ultrasonically, played an important role for promoting the synthesis process of PB via a spontaneous redox reaction between Fe(3+) and [Fe(CN)6](3-). The PPy film has been electro-polymerized to improve the electrochemical stability of the PPy/GQDs@PB/GF electrode. The as-prepared electrode was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), infrared spectroscopy (IR), X-ray diffraction (XRD) and electrochemical methods. It exhibited an excellent activity for the electrocatalytic oxidation of l-cys, with a detection sensitivity equal to 0.41 Amol(-1) L for a concentration range of 0.2-50 μmolL(-1), and equal to 0.15 Amol(-1) L for a concentration range of 50-1000 μmolL(-1). A low detection limit of 0.15 μmolL(-1), as well as a remarkable long-time stability and a negligible sensitivity to interfering analytes, were also ascertained.

  9. A study of a novel Na ion battery and its anodic degradation using sodium rich prussian blue cathode coupled with different titanium based oxide anodes

    NASA Astrophysics Data System (ADS)

    Mukherjee, Santanu; Bates, Alex; Schuppert, Nicholas; Son, Byungrak; Kim, Joo Gon; Choi, Jae Sung; Choi, Moon Jong; Lee, Dong-Ha; Kwon, Osung; Jasinski, Jacek; Park, Sam

    2015-07-01

    This paper analyzes the behavior and studies the thermal degradation phenomena of a novel sodium rich Prussian blue cathode with a sodium deficient and sodium rich anode system viz. amorphous TiO2, crystalline (pristine), and heat treated TiO2 and Na2Ti3O7, respectively. The primary aim of the research was to demonstrate the superiority of the Na2Ti3O7 anode, which in principle can be considered "pre-stressed" by Na atoms when converted from TiO2 to Na2Ti3O7. Another motive of the research was to analyze exhaustively the layered anode structure and its degradation phenomena using the unique technique of thermal imaging to correlate it with post cycled X-ray diffraction (XRD) and an AC impedance study. The Na2Ti3O7 system was seen as more stable than the other tested TiO2 based anodes and produced an open circuit voltage (OCV) of 3.59 V and a maximum specific capacity of 92.18 mAh g-1 when the electrolyte used was dissolved in an organic solvent. Under the same conditions, the TiO2 sample showed an OCV of 3.41 V and a maximum specific capacity of 71.93 mAh g-1. Thermal imaging studies show that the maximum electrochemical degradation occurs at the anode of the samples with the TiO2 sample being more susceptible to corrosion.

  10. Prussian blue-gold nanoparticles-ionic liquid functionalized reduced graphene oxide nanocomposite as label for ultrasensitive electrochemical immunoassay of alpha-fetoprotein.

    PubMed

    Gao, Qi; Liu, Na; Ma, Zhanfang

    2014-06-04

    In this work, poly(diallyldimethylammonium chloride) (PDDA) protected Prussian blue/gold nanoparticles/ionic liquid functionalized reduced graphene oxide (IL-rGO-Au-PDDA-PB) nanocomposite was fabricated. The resulting nanocomposite exhibited high biocompatibility, conductivity and catalytic activity. To assess the performance of the nanocomposite, a sensitive sandwich-type immunosensor was constructed for detecting alpha-fetoprotein (AFP). Greatly enhanced sensitivity for this immunosensor was based on triple signal amplification strategies. Firstly, IL-rGO modified electrode was used as biosensor platform to capture a large amount of antibody due to its increased surface area, thus amplifying the detection response. Secondly, a large number of Au-PDDA-PB was conjugated on the surface of IL-rGO, which meant the enrichment of the signal and the more immobilization of label antibody. Finally, the catalytic reaction between H2O2 and the IL-rGO-Au-PDDA-PB nanocomposite further enhanced the signal response. The signals increased linearly with AFP concentrations in the range of 0.01-100 ng mL(-1). The detection limit for AFP was 4.6 pg mL(-1). The immunosensor showed high sensitivity, excellent selectivity and good stability. Moreover, the immunosensor was applied to the analysis of AFP in serum sample with satisfactory result.

  11. 3D-Printed Fluidic Devices for Nanoparticle Preparation and Flow-Injection Amperometry Using Integrated Prussian Blue Nanoparticle-Modified Electrodes

    PubMed Central

    Bishop, Gregory W.; Satterwhite, Jennifer E.; Bhakta, Snehasis; Kadimisetty, Karteek; Gillette, Kelsey M.; Chen, Eric; Rusling, James F.

    2015-01-01

    A consumer-grade fused filament fabrication (FFF) 3D printer was used to construct fluidic devices for nanoparticle preparation and electrochemical sensing. Devices were printed using poly(ethylene terephthalate) and featured threaded ports to connect polyetheretherketone (PEEK) tubing via printed fittings prepared from acrylonitrile butadiene styrene (ABS). These devices included channels designed to have 800 × 800 µm2 square cross sections and were semitransparent to allow visualization of the solution-filled channels. A 3D-printed device with a Y-shaped mixing channel was used to prepare Prussian blue nanoparticles (PBNPs) under flow rates of 100 to 2000 µL min−1. PBNPs were then attached to gold electrodes for hydrogen peroxide sensing. 3D-printed devices used for electrochemical measurements featured threaded access ports into which a fitting equipped with reference, counter, and PBNP-modified working electrodes could be inserted. PBNP-modified electrodes enabled amperometric detection of H2O2 in the 3D-printed channel by flow-injection analysis, exhibiting a detection limit of 100 nM and linear response up to 20 µM. These experiments show that a consumer-grade FFF printer can be used to fabricate low-cost fluidic devices for applications similar to those that have been reported with more expensive 3D-printing methods. PMID:25901660

  12. Prussian blue/serum albumin/indocyanine green as a multifunctional nanotheranostic agent for bimodal imaging guided laser mediated combinatorial phototherapy.

    PubMed

    Sahu, Abhishek; Lee, Jong Hyun; Lee, Hye Gyeong; Jeong, Yong Yeon; Tae, Giyoong

    2016-08-28

    Developing novel nanotheranostic agent using only clinically approved materials is highly desirable and challenging. In this study, we combined three clinically approved materials, Prussian blue (PB), serum albumin (BSA), and indocyanine green (ICG), by a simple and biocompatible method to prepare a multifunctional theranostic PB-BSA-ICG nanoparticle. The multifunctional nanoparticle system could provide dual mode magnetic resonance (MR) and near infrared (NIR) fluorescence imaging as well as combined photothermal and photodynamic (PTT-PDT) therapy in response to a single NIR laser. This nanoparticle showed an excellent stability in physiological solutions and could suppress the photo-instability of ICG. In the absence of light, the nanoparticles showed no cytotoxicity, but significant cell death was induced through combined PTT-PDT effect after irradiation with NIR laser light. A high tumor accumulation and minimal nonspecific uptake by other major organs of PB-BSA-ICG nanoparticle were observed in vivo, analyzed by T1-weighted MR and NIR fluorescence bimodal imaging in tumor xenograft mice after intravenous injection. The nanoparticles efficiently suppressed the tumor growth through combinatorial phototherapy with no tumor recurrence upon a single NIR laser irradiation. These results demonstrated that PB-BSA-ICG is potentially an interesting nanotheranostic agent for imaging guided cancer therapy by overcoming the limitations of each technology and enhancing the therapeutic efficiency as well as reducing side effects.

  13. Facile synthesis of Prussian blue nanocubes/silver nanowires network as a water-based ink for the direct screen-printed flexible biosensor chips.

    PubMed

    Yang, Pengqi; Peng, Jingmeng; Chu, Zhenyu; Jiang, Danfeng; Jin, Wanqin

    2017-06-15

    The large-scale fabrication of nanocomposite based biosensors is always a challenge in the technology commercialization from laboratory to industry. In order to address this issue, we have designed a facile chemical method of fabricated nanocomposite ink applied to the screen-printed biosensor chip. This ink can be derived in the water through the in-situ growth of Prussian blue nanocubes (PBNCs) on the silver nanowires (AgNWs) to construct a composite nanostructure by a facile chemical method. Then a miniature flexible biosensor chip was screen-printed by using the prepared nanocomposite ink. Due to the synergic effects of the large specific surface area, high conductivity and electrocatalytic activity from AgNWs and PBNCs, the as-prepared biosensor chip exhibited a fast response (<3s), a wider linear response from 0.01 to 1.3mM with an ultralow LOD=5µm, and the ultrahigh sensitivities of 131.31 and 481.20µAmM(-1)cm(-2) for the detections of glucose and hydrogen peroxide (H2O2), respectively. Furthermore, the biosensor chip exhibited excellent stability, good reproducibility and high anti-interference ability towards physiological substances under a very low working potential of -0.05. Hence, the proposed biosensor chip also showed a promising potential for the application in practical analysis.

  14. Amperometric biosensor based on prussian blue and nafion modified screen-printed electrode for screening of potential xanthine oxidase inhibitors from medicinal plants.

    PubMed

    El Harrad, Loubna; Amine, Aziz

    2016-04-01

    A simple and sensitive amperometric biosensor was developed for the screening of potential xanthine oxidase inhibitors from medicinal plants. This biosensor was prepared by immobilization of xanthine oxidase on the surface of prussian blue modified screen-printed electrodes using nafion and glutaraldehyde. The developed biosensor showed a linear amperometric response at an applied potential of +0.05 V toward the detection of hypoxanthine from 5 μM to 45 μM with a detection limit of 0.4 μM (S/N=3) and its sensitivity was found to be 600 mA M(-1) cm(-2). In addition, the biosensor exhibited a good storage stability. The inhibition of xanthine oxidase by allopurinol was studied under the optimized conditions. The linear range of allopurinol concentration is obtained up to 2.5 μM with an estimated 50% of inhibitionI50=1.8 μM. The developed biosensor was successfully applied to the screening of xanthine oxidase inhibitors from 13 medicinal plants belonging to different families. Indeed, Moroccan people traditionally use these plants as infusion for the treatment of gout and its related symptoms. For this purpose, water extracts obtained from the infusion of these plants were used for the experiments. In this work, 13 extracts were assayed and several of them demonstrated xanthine oxidase inhibitory effect, with an inhibition greater than 50% compared to spectrophotometry measurements that only few extracts showed an inhibition greater than 50%.

  15. Enhanced adsorption of cesium on PVA-alginate encapsulated Prussian blue-graphene oxide hydrogel beads in a fixed-bed column system.

    PubMed

    Jang, Jiseon; Lee, Dae Sung

    2016-10-01

    A continuous fixed-bed column study was performed using PVA-alginate encapsulated Prussian blue-graphene oxide (PB-GO) hydrogel beads as a novel adsorbent for the removal of cesium from aqueous solutions. The effects of different operating parameters, such as initial cesium concentration, pH, bed height, flow rate, and bead size, were investigated. The maximum adsorption capacity of the PB-GO hydrogel beads was 164.5mg/g at an initial cesium concentration of 5mM, bed height of 20cm, and flow rate of 0.83mL/min at pH 7. The Thomas, Adams-Bohart, and Yoon-Nelson models were applied to the experimental data to predict the breakthrough curves using non-linear regression. Although both the Thomas and Yoon-Nelson models showed good agreement with the experimental data, the Yoon-Nelson model was found to provide the best representation for cesium adsorption on the adsorbent, based on the χ(2) analysis.

  16. Glucose biosensor based on covalent immobilization of enzyme in sol-gel composite film combined with Prussian blue/carbon nanotubes hybrid.

    PubMed

    Fu, Guanglei; Yue, Xiuli; Dai, Zhifei

    2011-05-15

    A novel electrochemical glucose biosensor was developed based on in situ covalent immobilization of glucose oxidase (GOx) by one-pot chitosan (CS)-incorporated sol-gel process in the presence of Prussian blue deposited multi-walled carbon nanotubes hybrids (PB/MWNTs) using 3-isocyanatopropyltriethoxysilane (ICPTES) as both a sol-gel precursor and a covalent coupling agent for GOx and CS. The electrode modified with the PB/MWNTs-GOx-CS-ICPTES sol-gel composite film showed good electrical conductivity and effective low-potential electron transfer mediation toward H2O2 reduction attributed to the incorporation of PB/MWNTs. The biosensor exhibited a linear response to glucose in the concentration range from 2.5×10(-5) to 1.3×10(-3) M with a correlation coefficient of 0.9998, a detection limit of 7.5×10(-6) M, a low response time (10s ), good sensitivity and high anti-interference ability. Compared with the control biosensor based on the traditional tetraethoxysilane derived sol-gel composite film, the biosensor showed a similarly small apparent Michaelis-Menten constant of 3.67 mM but much higher electrochemical and biosensing stability.

  17. A molecularly-imprinted electrochemical sensor based on a graphene-Prussian blue composite-modified glassy carbon electrode for the detection of butylated hydroxyanisole in foodstuffs.

    PubMed

    Cui, Min; Liu, Su; Lian, Wenjing; Li, Jie; Xu, Wei; Huang, Jiadong

    2013-10-21

    In this study, we developed a novel molecularly-imprinted electrochemical sensor based on a glassy carbon electrode (GCE) decorated by graphene-Prussian blue (GR-PB) composites for the selective and sensitive determination of butylated hydroxyanisole (BHA). The molecularly-imprinted polymers (MIPs) were synthesized by BHA and pyrrole as the template molecule and functional monomer, respectively. Also, the MIPs were assembled on the surface of the GR-PB/GCE by electropolymerization. The sensor was characterized by cyclic voltammetry (CV), scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and chronoamperometry. It was confirmed that the synergistic effects of GR and PB could improve the electrochemical response and the sensitivity of the sensor. The linear range of the sensor was from 9 × 10(-8) mol L(-1) to 7 × 10(-5) mol L(-1), with a limit of detection (LOD) of 7.63 × 10(-8) mol L(-1) (S/N = 3). The proposed sensor displayed high selectivity, excellent stability and good reproducibility for the determination of BHA. It was successfully applied to the determination of BHA in real samples.

  18. The monoamine oxidase inhibition properties of selected structural analogues of methylene blue.

    PubMed

    Delport, Anzelle; Harvey, Brian H; Petzer, Anél; Petzer, Jacobus P

    2017-04-01

    The thionine dye, methylene blue (MB), is a potent inhibitor of monoamine oxidase (MAO) A, a property that may, at least in part, mediate its antidepressant effects in humans and animals. The central inhibition of MAO-A by MB has also been linked to serotonin toxicity (ST) which may arise when MB is used in combination with serotonergic drugs. Structural analogues and the principal metabolite of MB, azure B, have also been reported to inhibit the MAO enzymes, with all compounds exhibiting specificity for the MAO-A isoform. To expand on the structure-activity relationships (SARs) of MAO inhibition by MB analogues, the present study investigates the human MAO inhibition properties of five MB analogues: neutral red, Nile blue, new methylene blue, cresyl violet and 1,9-dimethyl methylene blue. Similar to MB, these analogues also are specific MAO-A inhibitors with cresyl violet (IC50=0.0037μM), Nile blue (IC50=0.0077μM) and 1,9-dimethyl methylene blue (IC50=0.018μM) exhibiting higher potency inhibition compared to MB (IC50=0.07μM). Nile blue also represents a potent MAO-B inhibitor with an IC50 value of 0.012μM. From the results it may be concluded that non-thionine MB analogues (e.g. cresyl violet and Nile blue) also may exhibit potent MAO inhibition, a property which should be considered when using these compounds in pharmacological studies. Benzophenoxazines such as cresyl violet and Nile blue are, similar to phenothiazines (e.g. MB), representative of high potency MAO-A inhibitors with a potential risk of ST.

  19. Surfactant-promoted Prussian Blue-modified carbon electrodes: enhancement of electro-deposition step, stabilization, electrochemical properties and application to lactate microbiosensors for the neurosciences.

    PubMed

    Salazar, P; Martín, M; O'Neill, R D; Roche, R; González-Mora, J L

    2012-04-01

    We report here for the first time a comparison of the beneficial effects of different cationic surfactants - cetyl trimethyl ammonium bromide (CTAB), benzethonium chloride (BZT) and cetylpyridinium chloride (CPC) - for the electrochemical synthesis of Prussian Blue (PB) films, using cyclic voltammetry (CV), on screen-printed carbon electrodes (SPCEs). Their electrochemical properties were investigated, paying special attention to parameters such as the amount of PB deposited, film thickness, charge transfer rate, permeability, reversibility, stability and sensitivity to hydrogen peroxide detection. All surfactant-enhanced PB-modified SPCEs displayed a significant improvement in their electrochemical properties compared with PB-modified SPCEs formed in the absence of surfactants. Surfactant-modified electrodes displayed a consistently higher PB surface concentration value of 2.1±0.4×10(-8) mol cm(-2) (mean±SD, n=3) indicating that PB deposition efficiency was improved 2-3 fold. K(+) and Na(+) permeability properties of the films were also studied, as were kinetic parameters, such as the surface electron transfer rate constant (k(s)) and the transfer coefficient (α). The hydrogen peroxide sensitivity of surfactant-modified PB films generated by 10 electro-deposition CV cycles gave values of 0.63 A M(-1) cm(-2), which is higher than those reported previously for SPCEs by other authors. Finally, the first lactate microbiosensor described in the literature based on BZT-modified PB-coated carbon fiber electrodes is presented. Its very small cross-section (~10 μm diameter) makes it particularly suitable for neuroscience studies in vivo.

  20. An ultra-sensitive acetylcholinesterase biosensor based on reduced graphene oxide-Au nanoparticles-β-cyclodextrin/Prussian blue-chitosan nanocomposites for organophosphorus pesticides detection.

    PubMed

    Zhao, Haiyan; Ji, Xueping; Wang, Beibei; Wang, Na; Li, Xianrui; Ni, Ruixing; Ren, Jujie

    2015-03-15

    This work reports a novel, ultrasensitive, and selective sensing platform based on a direct electrodeposition of electrochemical reduced graphene oxide (ERGO)-Au nanoparticles (AuNPs)-β-cyclodextrin (β-CD) and Prussian blue-chitosan (PB-CS) on glass carbon electrode (GCE) for efficiently fixed acetylcholinesterase (AChE) to fabricate organophosphorus pesticides (OPs) biosensor. The PB-CS not only effectively catalyzed the oxidation of thiocholine (TCh), but also shifted its oxidation potential from 0.68 to 0.2V, and accordingly the sensitivity of the biosensor was obviously improved. The synergistic effect between ERGO and AuNPs significantly promoted the electron transfer between PB and GCE, and remarkably enhanced the electrochemical oxidation of TCh. Besides, β-CD could interact with substrate by reversible bonding, which is contribute to increase the enrichment of the substrate and improve the selectivity and sensitivity of the biosensor. The integration of ERGO-AuNPs-β-CD with PB-CS provided an advantageous and high-performance platform for sensing applications. Based on the inhibition of OPs on AChE activity, the sensor showed wide linear ranges of 7.98-2.00×10(3)pgmL(-1) and 4.3-1.00×10(3)pgmL(-1) with low detection limits of 4.14pgmL(-1) and 1.15pgmL(-1) for malathion and carbaryl, respectively. The proposed biosensor exhibited short response time, good stability and high sensitivity, which can be used for direct analysis of practical samples.

  1. Rate of Iron Transfer Through the Horse Spleen Ferritin Shell Determined by the Rate of Formation of Prussian Blue and Fe-desferrioxamine Within the Ferritin Cavity

    NASA Technical Reports Server (NTRS)

    Zhang, Bo; Watt, Richard K.; Galvez, Natividad; Dominquez-Vera, Jose M.; Watt, Gerald D.

    2005-01-01

    Iron (2+ and 3+) is believed to transfer through the three-fold channels in the ferritin shell during iron deposition and release in animal ferritins. However, the rate of iron transit in and out through these channels has not been reported. The recent synthesis of [Fe(CN)(sub 6)](3-), Prussian Blue (PB) and desferrioxamine (DES) all trapped within the horse spleen ferritin (HoSF) interior makes these measurements feasible. We report the rate of Fe(2+) penetrating into the ferritin interior by adding external Fe(2+) to [Fe(CN)(sub 6)](3-) encapsulated in the HoSF interior and measuring the rate of formation of the resulting encapsulated PB. The rate at which Fe(2+) reacts with [Fe(CN)(sub 6)](3-) in the HoSF interior is much slower than the formation of free PB in solution and is proceeded by a lag period. We assume this lag period and the difference in rate represent the transfer of Fe(2+) through the HoSF protein shell. The calculated diffusion coefficient, D approx. 5.8 x 10(exp -20) square meters per second corresponds to the measured lag time of 10-20 s before PB forms within the HoSF interior. The activation energy for Fe(2+) transfer from the outside solution through the protein shell was determined to be 52.9 kJ/mol by conducting the reactions at 10 to approximately 40 C. The reaction of Fe(3+) with encapsulated [Fe(CN)6](4-) also readily forms PB in the HoSF interior, but the rate is faster than the corresponding Fe(2+) reaction. The rate for Fe(3+) transfer through the ferritin shell was confirmed by measuring the rate of the formation of Fe-DES inside HoSF and an activation energy of 58.4 kJ/mol was determined. An attempt was made to determine the rate of iron (2+ and 3+) transit out from the ferritin interior by adding excess bipyridine or DES to PB trapped within the HoSF interior. However, the reactions are slow and occur at almost identical rates for free and HoSF-encapsulated PB, indicating that the transfer of iron from the interior through the

  2. An electrochemical biosensor for rapid detection of E. coli O157:H7 with highly efficient bi-functional glucose oxidase-polydopamine nanocomposites and Prussian blue modified screen-printed interdigitated electrodes.

    PubMed

    Xu, Meng; Wang, Ronghui; Li, Yanbin

    2016-09-21

    The presence of pathogenic bacteria in foods has always been a great threat to the wellbeing of people and the revenue of food manufacturers. Therefore, the demand for advanced detection methods that can sensitively and rapidly detect these pathogens has been of great importance. This study reports an electrochemical biosensor for rapid detection of E. coli O157:H7 with the integration of bifunctional glucose oxidase (GOx)-polydopamine (PDA) based polymeric nanocomposites (PMNCs) and Prussian blue (PB) modified screen-printed interdigitated microelectrodes (SP-IDMEs). The core-shell magnetic beads (MBs)-GOx@PDA PMNCs were first synthesized by the self-polymerization of dopamine (DA). Gold nanoparticles (AuNPs) were dispersed on the surface of PMNCs through biochemical synthesis to achieve further highly efficient adsorption of antibodies (ABs) and GOx. The final product ABs/GOxext/AuNPs/MBs-GOx@PDA PMNCs served as the carrier to separate target bacteria from food matrices as well as the amplifier for electrochemical measurement. The unbound PMNCs were separated by a filtration step and transferred into glucose solution to allow the enzymatic reaction to occur. The change of the current response was measured with an electrochemical detector using PB-modified SP-IDMEs. The constructed biosensor has been proven to be able to detect E. coli O157:H7 with the detection limit of 10(2) cfu ml(-1). The bifunctional PMNCs contain a high load of enzyme and can optimally utilize the binding sites on bacterial cells, which efficiently amplify the signals for measurement. The biosensor in this study exhibited good specificity, reproducibility, and stability and is expected to have a great impact on applications in the detection of foodborne pathogens.

  3. LC-MS/MS analysis of palytoxin analogues in blue humphead parrotfish Scarus ovifrons causing human poisoning in Japan.

    PubMed

    Suzuki, Toshiyuki; Watanabe, Ryuichi; Matsushima, Ryoji; Ishihara, Kenji; Uchida, Hajime; Kikutsugi, Saori; Harada, Tomoko; Nagai, Hiroshi; Adachi, Masao; Yasumoto, Takeshi; Murata, Masakazu

    2013-01-01

    Since 1953, a total of 27 human poisoning cases caused by the consumption of blue humphead parrotfish, Scarus ovifrons, have been reported in Japan. Characteristic symptoms are severe muscle pain associated with rhabdomyolysis. Although it is believed that palytoxin, which is one of the most potent non-protein marine biotoxins, is the most likely causative toxin in blue humphead parrotfish poisoning, palytoxin has not been proven conclusively as the causative toxin because of lack of a reliable and sensitive analytical method for palytoxin. In 2011, human poisoning cases caused by the consumption of blue humphead parrotfish occurred in Miyazaki and Tokyo. In our present study, an LC-MS/MS method for palytoxin and its analogues in the blue humphead parrotfish samples causing the human poisoning cases in 2011 was developed and the samples were analysed by using the newly developed LC-MS/MS method. Palytoxin and its analogues were not detected in the samples from the food poisoning cases. The LC-MS/MS findings therefore do not support the recently accepted hypothesis that palytoxin is the causative agent in blue humphead parrotfish poisoning in Japan.

  4. Intensely colored mixed-valence iron(II) iron(III) formate analogue of Prussian Blue exhibits néel N-type ferrimagnetism.

    PubMed

    Hagen, Karl S; Naik, Sunil G; Huynh, Boi Hanh; Masello, Antonio; Christou, George

    2009-06-10

    The reaction of colorless iron(II) formate or the mixed-valence cluster Fe(3)O(MeCOO)(6)(H(2)O)(3) with formic acid in dimethylformamide exposed to air at 110 degrees C affords black crystals of the mixed-valence (Me(2)NH(2))[Fe(II)Fe(III)(HCOO)(6)] three-dimensional (3D) structure in which the cations occupy half of the channels. The structure consists of alternating layers of Fe(II)O(6) [Fe(1)-O(1), 2.119(1) A] and Fe(III)O(6) [Fe(2)-O(2), 2.0049(9) A] octahedra bridged by anti-anti-bonded formates to afford an open-framework 3D structure. The structure is very similar to those of (Me(2)NH(2))[Fe(II)(HCOO)(3)] and [Fe(III)(HCOO)(3)].HCOOH, both of which are colorless. The black crystals appear dark-purple (lambda(max) approximately 520 nm) when powdered. The room-temperature Mössbauer spectrum confirms the 1:1 ratio of Fe(II) (delta = 1.03 mm/s, DeltaE(Q) = 1.16 mm/s) and Fe(III) (delta = 0.62 mm/s, DeltaE (Q) = 0.49 mm/s). Magnetic ordering that includes negative magnetization at low fields occurs at low temperature. The only molecular-based magnetic materials in which this phenomenon has been observed are the 2D polyiron(II,III) oxalates A[Fe(II)Fe(III)(C(2)O(4))(3)] (A = R(4)N(+) cation).

  5. Prussian Reform: The Recovery of a Nation

    DTIC Science & Technology

    2014-12-01

    the balance of power among the German states and northern Europe. The reputation of the army and the strength of the Prussian nation, born out of the...the traditional Germanic hegemony that had long held sway over the balance of power among the German states and northern Europe. The reputation of the...with or as part of a higher echelon combined arms formation.48 The Prussian regiments mobilized in 1806 were either line or light infantry, heavy

  6. Savant officials in the Prussian mining administration.

    PubMed

    Klein, Ursula

    2012-07-01

    In the second half of the eighteenth century, the Prussian State supported savants who combined learned inquiry into nature with technical work. Members of the physical and mathematical classes of the Royal Prussian Academy of Sciences were involved in State projects such as surveying for the construction of canals, chemical analysis of Silesian iron, production of porcelain and of beet sugar. Some of these men were truly 'hybrid' experts living both in the worlds of State-directed manufacture and academic natural inquiry. Among these savant experts there was a particular sub-group that is at the centre of this paper: mining officials who were also recognized as mineralogists, geologists and chemists. The paper describes and analyses the training and the varied technical and scientific activities of these 'savant officials'. At the centre of attention are the travels of inspection of the mineralogist and mining official Carl Abraham Gerhard (1738-1821) in the late 1760s. I argue that Gerhard's travels of inspection were at the same time geological travels and that savant officials like Gerhard made a significant contribution to the fledgling science of geology.

  7. The Prussian Academy of Sciences during the Third Reich

    ERIC Educational Resources Information Center

    Notzoldt, Peter; Walther, Peter Th.

    2004-01-01

    In 1933, the Prussian Academy of Sciences and Humanities was an exclusive learned society, out of touch with modern methods and funding, which had also failed to re-establish itself as a "centre of research". During the Nazi regime, it was at best peripherally involved in the restructuring of German academia. While some of its members…

  8. Hydroxynaphthyridine-derived group III metal chelates: wide band gap and deep blue analogues of green Alq3 (tris(8-hydroxyquinolate)aluminum) and their versatile applications for organic light-emitting diodes.

    PubMed

    Liao, Szu-Hung; Shiu, Jin-Ruei; Liu, Shun-Wei; Yeh, Shi-Jay; Chen, Yu-Hung; Chen, Chin-Ti; Chow, Tahsin J; Wu, Chih-I

    2009-01-21

    A series of group III metal chelates have been synthesized and characterized for the versatile application of organic light-emitting diodes (OLEDs). These metal chelates are based on 4-hydroxy-1,5-naphthyridine derivates as chelating ligands, and they are the blue version analogues of well-known green fluorophore Alq(3) (tris(8-hydroxyquinolinato)aluminum). These chelating ligands and their metal chelates were easily prepared with an improved synthetic method, and they were facially purified by a sublimation process, which enables the materials to be readily available in bulk quantity and facilitates their usage in OLEDs. Unlike most currently known blue analogues of Alq(3) or other deep blue materials, metal chelates of 4-hydroxy-1,5-naphthyridine exhibit very deep blue fluorescence, wide band gap energy, high charge carrier mobility, and superior thermal stability. Using a vacuum-thermal-deposition process in the fabrication of OLEDs, we have successfully demonstrated that the application of these unusual hydroxynaphthyridine metal chelates can be very versatile and effective. First, we have solved or alleviated the problem of exciplex formation that took place between the hole-transporting layer and hydroxynaphthyridine metal chelates, of which OLED application has been prohibited to date. Second, these deep blue materials can play various roles in OLED application. They can be a highly efficient nondopant deep blue emitter: maximum external quantum efficiency eta(ext) of 4.2%; Commision Internationale de L'Eclairage x, y coordinates, CIE(x,y) = 0.15, 0.07. Compared with Alq(3), Bebq(2) (beryllium bis(benzoquinolin-10-olate)), or TPBI (2,2',2''-(1,3,5-phenylene)tris(1-phenyl-1H-benzimidazole), they are a good electron-transporting material: low HOMO energy level of 6.4-6.5 eV and not so high LUMO energy level of 3.0-3.3 eV. They can be ambipolar and possess a high electron mobility of 10(-4) cm(2)/V s at an electric field of 6.4 x 10(5) V/cm. They are a

  9. Analogue Gravity.

    PubMed

    Barceló, Carlos; Liberati, Stefano; Visser, Matt

    2011-01-01

    Analogue gravity is a research programme which investigates analogues of general relativistic gravitational fields within other physical systems, typically but not exclusively condensed matter systems, with the aim of gaining new insights into their corresponding problems. Analogue models of (and for) gravity have a long and distinguished history dating back to the earliest years of general relativity. In this review article we will discuss the history, aims, results, and future prospects for the various analogue models. We start the discussion by presenting a particularly simple example of an analogue model, before exploring the rich history and complex tapestry of models discussed in the literature. The last decade in particular has seen a remarkable and sustained development of analogue gravity ideas, leading to some hundreds of published articles, a workshop, two books, and this review article. Future prospects for the analogue gravity programme also look promising, both on the experimental front (where technology is rapidly advancing) and on the theoretical front (where variants of analogue models can be used as a springboard for radical attacks on the problem of quantum gravity).

  10. Preliminary Results Concerning the Influence of Human Kisspeptin on LH Secretion in Prussian Carp (Carassius gibelio) Females at the Stage of Ovarian Recrudescence and Spawning Season.

    PubMed

    Gosiewski, Grzegorz; Sokolowska-Mikolajczyk, Miroslawa; Chyb, Jaroslaw; Socha, Magdalena

    2015-01-01

    The aim of the experiments was to evaluate the influence of human kisspeptin on LH secretion of Prussian carp (Carassius gibelio) females during ovarian recrudescence and spawning season. For the experiments, human kisspeptin KISS1 (0.1 mg kg(-1) of body weight--b.w.), GnRH analogue (Des Gly(10), D-Ala(6)) GnRH-A (20 µg kg(-1) b.w.) and dopamine antagonist (pimozide) (5 mg kg(-1) b.w.) were used alone or in combinations. At 3, 6, 12, 24 hours after injection(s) blood samples were collected from all fish. LH levels were measured in plasma with the use of the ELISA method. KISS1 did not show any significant effects on spontaneous LH secretion in both tested seasons. At 12 hours sampling time (both stages of gonad maturity) a combination of tested compounds (GnRH-A+KISS1) significantly increased LH release in comparison with the control. In the stage of gonad recrudescence KISS1 significantly increased LH secretion evoked by pimozide at 24 hours. A combination of three components: KISS1, GnRH-A, and pimozide significantly decreased LH secretion in comparison to LH secretion evoked by GnRH-A and pimozide during stage of gonad recrudescence. These results suggest that kisspeptin is involved in seasonal control of reproduction in Prussian carp. The possible interaction of kisspeptin and the dopaminergic system is also discussed.

  11. Sequential Assembly of Magnetic Prussian Blue Films with Photo-Induced Magnetism

    NASA Astrophysics Data System (ADS)

    Meisel, Mark W.

    2004-11-01

    Despite interest in the area of molecule-based magnets, there are few efforts to investigate magnetism in monolayers, surface layers, and other thin films based on these materials. New synthetic methods developed by our groups now permit deposition of single layer and multilayer thin films of cyanometallate molecule-based magnet systems. These monolayers and surface films are inherently anisotropic, thereby allowing magnetic characterizations that are only possible because of our method of fabrication. Two examples will be presented. The distance dependence of dipolar interactions on magnetic order is illustrated by comparing a monolayer, bilayer, and multilayers of a mixed organic/inorganic Fe^3+/Ni^2+ cyanometallate two-dimensional network. The magnetometry results demonstrate the influence of dipolar interactions at an interlayer separation of greater than 35 ÅSecondly, anisotropic response of the photoinduced magnetism in a thin film of Rb_jCo_k[Fe(CN)_6]l \\cdot nH_2O, which experiences a ferrimagnetic transition near 20 K, has been discovered. The photo-induced magnetism may result in a net increase or decrease of the total magnetization of the sample when the externally applied magnetic field is oriented parallel or perpendicular to the plane of the films. The strength of this anisotropy depends on the thickness of the film and the size of the magnetic domains, and the photo-induced magnetism was effective in magnetic fields up to 27 T while at 4.7 K. This work, co-authored with D. R. Talham, was performed with J.-H. Park, F. Frye, Y.-D. Huh, E. Čižmár, and S. Lane, and was supported, in part, by NSF DMR-0305371.

  12. [Maternity blues].

    PubMed

    Gonidakis, F

    2007-04-01

    Maternity blues is a transient change of mood that occurs mainly between the 1st and 10th day of puerpartum and is characterized by bursts of tears, mild depressive mood, anxiety and liability of mood. The frequency of maternity blues varies in different studies form 4% to 80%. A number of biological and psychosocial parameters have been studied in order to determine their correlation with maternity blues. The most well studied biological parameters are progesterone and cortizol although their relation with maternity blues has not yet been clearly defined. Stress and the emotional state of the woman during pregnancy as well as history of mood disorders or maternity blues in a previous birth are the psychosocial parameters that are more likely to correlate with the occurrence of maternity blues. Most of the authors suggest that information on maternity blues and reassurance of the woman are the best way to deal with maternity blues both on preventive and therapeutical basis.

  13. The Prussian Academy of Sciences and Humanities during the Weimar Republic

    ERIC Educational Resources Information Center

    Hardtwig, Wolfgang

    2004-01-01

    The German Revolution of November 1918 dramatically altered the Academy's view of its relationship with government. In particular, the Academy's Prussian tradition had to be rethought. From initial wariness to grudging acceptance, the Academy came to accept the Weimar regime. This paper studies the politics of the Academy, uncovers factions and…

  14. Blue Note

    ScienceCinema

    Murray Gibson

    2016-07-12

    Argonne's Murray Gibson is a physicist whose life's work includes finding patterns among atoms. The love of distinguishing patterns also drives Gibson as a musician and Blues enthusiast."Blue" notes are very harmonic notes that are missing from the equal temperament scale.The techniques of piano blues and jazz represent the melding of African and Western music into something totally new and exciting.

  15. Blue Note

    SciTech Connect

    Murray Gibson

    2007-04-27

    Argonne's Murray Gibson is a physicist whose life's work includes finding patterns among atoms. The love of distinguishing patterns also drives Gibson as a musician and Blues enthusiast."Blue" notes are very harmonic notes that are missing from the equal temperament scale.The techniques of piano blues and jazz represent the melding of African and Western music into something totally new and exciting.

  16. Blue Laser.

    DTIC Science & Technology

    1985-12-01

    HOLLOW CATHODE LASER FABRICATION 13 4. EXPERIENCE WITH THE BLUE LASER 18 4.1 Operational and Processing Experience 18 4.2 Performance Testing 20 5...34 -. - . •. SECTION 3 BLUE HOLLOW CATHODE LASER FABRICATION This section presents an overview of the steps taken in creating a HCL. There is...to the laser assembly. These steps can actually be considered as the final steps in laser fabrication because some of them involve adding various

  17. Tailoring magnetic properties of electrodeposited thin films of the molecule-based magnet Cr5.5(CN)12 11.5H2O

    PubMed Central

    2012-01-01

    This paper reports on molecular-based magnetic thin films of Prussian blue analogues (PBA) with high critical temperatures composed of mixed-valence chromium cyanides. The thin films of PBA were synthesized by means of electrodeposition technique. Morphology and magnetic study are presented in a function of electrochemical deposition conditions. We present the electrochemical methods as a promising and effective tool for preparing molecular-based magnetic thin films of Prussian blue analogue. PMID:22531148

  18. Blue gods, blue oil, and blue people.

    PubMed

    Fairbanks, V F

    1994-09-01

    Studies of the composition of coal tar, which began in Prussia in 1834, profoundly affected the economies of Germany, Great Britain, India, and the rest of the world, as well as medicine and surgery. Such effects include the collapse of the profits of the British indigo monopoly, the growth in economic power of Germany based on coal tar chemistry, and an economic crisis in India that led to more humane tax laws and, ultimately, the independence of India and the end of the British Empire. Additional consequences were the development of antiseptic surgery and the synthesis of a wide variety of useful drugs that have eradicated infections and alleviated pain. Many of these drugs, particularly the commonly used analgesics, sulfonamides, sulfones, and local anesthetics, are derivatives of aniline, originally called "blue oil" or "kyanol." Some of these aniline derivatives, however, have also caused aplastic anemia, agranulocytosis, and methemoglobinemia (that is, "blue people"). Exposure to aniline drugs, particularly when two or three aniline drugs are taken concurrently, seems to be the commonest cause of methemoglobinemia today.

  19. Survey of Analogue Spacetimes

    NASA Astrophysics Data System (ADS)

    Visser, Matt

    Analogue spacetimes (and more boldly, analogue models both of and for gravity), have attracted significant and increasing attention over the last decade and a half. Perhaps the most straightforward physical example, which serves as a template for most of the others, is Bill Unruh's model for a dumb hole,(mute black hole, acoustic black hole), wherein sound is dragged along by a moving fluid—and can even be trapped behind an acoustic horizon. This and related analogue models for curved spacetimes are useful in many ways: analogue spacetimes provide general relativists with extremely concrete physical models to help focus their thinking, and conversely the techniques of curved spacetime can sometimes help improve our understanding of condensed matter and/or optical systems by providing an unexpected and countervailing viewpoint. In this chapter, I shall provide a few simple examples of analogue spacetimes as general background for the rest of the contributions.

  20. Comparison of computerized image analysis with traditional semiquantitative scoring of Perls' Prussian Blue stained hepatic iron deposition.

    PubMed

    Hall, A Peter; Davies, Wendy; Stamp, Katie; Clamp, Isabel; Bigley, Alison

    2013-01-01

    Image analysis is now routinely employed as a tool in toxicologic pathology to help quantitate end points of efficacy and safety. It is regarded as a proficient and a sensitive technique to generate numerical data that can be easily interrogated for statistical evaluation. Traditional semiquantitative pathology scoring on the other hand is sometimes regarded as less accurate due to the limitations of the scoring systems employed and the day-to-day variations often noted between pathologists. We therefore decided to generate an optimized histochemical staining and image analysis protocol to compare the accuracy of semiquantitative scoring with computerized image analysis. In order to achieve this, we describe a standardized protocol for staining and image analysis that eliminates or minimizes as many sources of error as possible. The results of this experiment demonstrate that despite consistent variations in scoring between two independent pathologists, correlation with image analysis data of 0.91 to 0.95 (Spearman's Rho test) was achieved. These data indicate that either image analysis or traditional semiquantitative scoring can generate accurate data. As a result of this, it appears that it is equally safe to employ either method dependent upon the complexity and the practicality of the task at hand provided that the experimental conditions are rigorously optimized and rigidly adhered to.

  1. Facile synthesis of air-stable Prussian white microcubes via a hydrothermal method

    SciTech Connect

    Hu, M.; Jiang, J.S.

    2011-05-15

    Research highlights: {yields} We have synthesized Prussian white microcubes in large quantities by a facile hydrothermal method for the first time. {yields} It is the first report about air-stable PW. {yields} The shape of crystals strongly depended on the concentration of K{sub 4}[Fe(CN){sub 6}], the hydrothermal temperature and the reaction duration. {yields} A layer-by-layer growth mechanism was proposed to explain the formation of PW microcubes. -- Abstract: Air-stable Prussian white (PW) microcubes were fabricated by the slow dissociation of K{sub 4}[Fe(CN){sub 6}] under hydrothermal condition without the protection of inert atmosphere. Moessbauer spectra and Fourier transform infrared (FT-IR) spectrum were used to characterize the composition of PW. X-ray diffraction (XRD) identified the obtained PW was monoclinic, and the purity was high. Scanning electron microscopy (SEM) images indicated the cubes were composed by solid cubes and hollow cubes. The shape of crystals strongly depended on the concentration of K{sub 4}[Fe(CN){sub 6}], the hydrothermal temperature as well as the reaction duration. The lower concentration and lower temperature resulted in perfect cubic crystals, while the higher concentration or the higher temperature resulted in irregular cubic crystals. After exposing in air for 2 months, no oxidation of PW occurred. To explain the formation of the PW microcubes, a layer-by-layer growth mechanism was put forward based on the low dissociation rate of K{sub 4}[Fe(CN){sub 6}]. The partially solubility of PW in water caused the formation of hollow cubes.

  2. The Blue Bottle Revisited.

    ERIC Educational Resources Information Center

    Vandaveer, Walter R., IV; Mosher, Mel

    1997-01-01

    Presents a modification of the classic Blue Bottle demonstration that involves the alkaline glucose reduction of methylene blue. Uses other indicators in the classic Blue Bottle to produce a rainbow of colors. (JRH)

  3. Aspartame and Its Analogues

    NASA Astrophysics Data System (ADS)

    Pavlova, L. A.; Komarova, T. V.; Davidovich, Yurii A.; Rogozhin, S. V.

    1981-04-01

    The results of studies on the biochemistry of the sweet taste are briefly reviewed. The methods of synthesis of "aspartame" — a sweet dipeptide — are considered, its structural analogues are described, and quantitative estimates are made of the degree of sweetness relative to sucrose. Attention is concentrated mainly on problems of the relation between the structure of the substance and its taste in the series of aspartyl derivatives. The bibliography includes 118 references.

  4. Quantum analogue computing.

    PubMed

    Kendon, Vivien M; Nemoto, Kae; Munro, William J

    2010-08-13

    We briefly review what a quantum computer is, what it promises to do for us and why it is so hard to build one. Among the first applications anticipated to bear fruit is the quantum simulation of quantum systems. While most quantum computation is an extension of classical digital computation, quantum simulation differs fundamentally in how the data are encoded in the quantum computer. To perform a quantum simulation, the Hilbert space of the system to be simulated is mapped directly onto the Hilbert space of the (logical) qubits in the quantum computer. This type of direct correspondence is how data are encoded in a classical analogue computer. There is no binary encoding, and increasing precision becomes exponentially costly: an extra bit of precision doubles the size of the computer. This has important consequences for both the precision and error-correction requirements of quantum simulation, and significant open questions remain about its practicality. It also means that the quantum version of analogue computers, continuous-variable quantum computers, becomes an equally efficient architecture for quantum simulation. Lessons from past use of classical analogue computers can help us to build better quantum simulators in future.

  5. Fluorescent analogues of methotrexate: characterization and interaction with dihydrofolate reductase.

    PubMed

    Kumar, A A; Kempton, R J; Anstead, G M; Freisheim, J H

    1983-01-18

    The dansylated derivatives of lysine and ornithine analogues of methotrexate exhibit fluorescence properties characteristic of the dansyl moiety with an excitation at 328 nm and an emission maximum at 580 nm in aqueous media. As in the case of dansyl amino acids, the fluorescence emission is dependent upon the polarity of the medium. In solvents of low dielectric constant there is an enhancement of the dansyl fluorescence intensity as well as a shift to shorter wavelengths. The dansylated analogues show a reduction in the quantum yields as compared to N epsilon-dansyl-L-lysine and 5-(N,N-dimethylamino)-1-naphthalenesulfonic acid. The absorption spectra of the two dansyl analogues are similar to the spectra of the parent basic amino acid precursors but with reduced molar extinction values. The two fluorescent analogues of methotrexate were found to be potent inhibitors of purified dihydrofolate reductases from Lactobacillus casei and from chicken liver. The binding of these fluorescent analogues to either dihydrofolate reductase resulted in 10-15-nm blue shift of the ligand emission maxima and a 2-5-fold enhancement of the emission. These fluorescent properties of the bound ligands indicate a possible interaction of the dansyl moiety with a region on the enzyme molecule which is more hydrophobic relative to the surrounding solvent.

  6. Bioluminescent properties of obelin and aequorin with novel coelenterazine analogues.

    PubMed

    Gealageas, Ronan; Malikova, Natalia P; Picaud, Sandrine; Borgdorff, Aren J; Burakova, Ludmila P; Brûlet, Philippe; Vysotski, Eugene S; Dodd, Robert H

    2014-04-01

    The main analytical use of Ca(2+)-regulated photoproteins from luminous coelenterates is for real-time non-invasive visualization of intracellular calcium concentration ([Ca(2+)]i) dynamics in cells and whole organisms. A limitation of this approach for in vivo deep tissue imaging is the fact that blue light emitted by the photoprotein is highly absorbed by tissue. Seven novel coelenterazine analogues were synthesized and their effects on the bioluminescent properties of recombinant obelin from Obelia longissima and aequorin from Aequorea victoria were evaluated. Only analogues having electron-donating groups (m-OCH3 and m-OH) on the C6 phenol moiety or an extended resonance system at the C8 position (1-naphthyl and α-styryl analogues) showed a significant red shift of light emission. Of these, only the α-styryl analogue displayed a sufficiently high light intensity to allow eventual tissue penetration. The possible suitability of this compound for in vivo assays was corroborated by studies with aequorin which allowed the monitoring of [Ca(2+)]i dynamics in cultured CHO cells and in hippocampal brain slices. Thus, the α-styryl coelenterazine analogue might be potentially useful for non-invasive, in vivo bioluminescence imaging in deep tissues of small animals.

  7. The Blue Water

    ERIC Educational Resources Information Center

    Berger, J. Joel

    1973-01-01

    Describes some of the advantages of an elementary science activity in which students discover that blowing through a straw into a bromthymol blue solution changes the color to yellow. Directions are provided for preparing the bromthymol blue solution. (JR)

  8. Blue nightshade poisoning

    MedlinePlus

    ... when someone eats parts of the blue nightshade plant. This article is for information only. DO NOT ... is found in the blue nightshade ( Solanum dulcamara ) plant, especially in the fruit and leaves.

  9. [A Prussian in Venice: the botanist Melchior Wieland (1520-1589), pioneer in botanical field research in the Levant].

    PubMed

    Herrmann, Sabine

    2015-01-01

    The Italian physician and botanist Prospero Alpini (1553-1617) is considered as one of the most famous 16th Century Italian botanists having explored the plant species of Egypt and the Near East. Alpinis best-known works as for example De medicina Egyptiorum (Venetijs 1591) or De plantis Aegypti liber (Venetijs 1592), however, wouldn't certainly have been made possible without the influence of his academic teacher, the Prussian physician and botanist Melchior Wieland (ca. 1520-1589), having been applied director of the botanical garden of Padua in 1561. This study is therefore dedicated to the life, academic career, works and reception of this nearly forgotten botanist.

  10. Analogue-to-Digital and Digital-to-Analogue Conversion.

    ERIC Educational Resources Information Center

    Gregory, Martin

    1997-01-01

    Discusses circuits for three-bit and four-bit analogue digital converters and digital analogue converters. These circuits feature slow operating speeds that enable the circuitry to be used to demonstrate the mode of operation using oscilloscopes and signal generators. (DDR)

  11. [Medical support of the 65th Army during the East Prussian offensive operation performed by the 2nd Belorussian Front].

    PubMed

    Shelepov, A M; Leonik, S I; Lemeshkin, R N

    2015-02-01

    Prussian offensive operation performed by the 2nd Belorussian Front. An activity of the medical An activity of the medical service of the 65th Army during the East Prussian offensive operation performed by the 2nd Belorussian Front is a typical example of the medical support of troops during the final stages of World War II. Forms and methods of medical support management, which were developed during the war, haven't lost their importance in modern conditions. These methods include the establishment of specialized surgical and therapeutic field hospital, establishment of medical institutions in the Army, which worked on the evacuation directions and reserve of mobile hospitals and transport, timely extension of the first echelons of the hospital base front to change institutions hospital deployed the army base. A research of experience in organizing medical support of the offensive operations performed during the last year of World War II provides the material for the development of the theory of modern medical support operations and ability to provide on this basis, the continuity of the hospitals, the continuity of qualified and specialized medical care, improve the performance of diagnostic and treatment work.

  12. Mammary Analogue Secretory Carcinoma.

    PubMed

    Stevens, Todd M; Parekh, Vishwas

    2016-09-01

    Mammary analogue secretory carcinoma (MASC) is a recently described salivary gland tumor that shares the same histologic appearance and ETV6 gene (12p13) rearrangement as secretory carcinoma of the breast. Prior to its recognition, MASC cases were commonly labeled acinic cell carcinoma and adenocarcinoma, not otherwise specified. Despite distinctive histologic features, MASC may be difficult to distinguish from other salivary gland tumors, in particular zymogen-poor acinic cell carcinoma and low-grade salivary duct carcinoma. Although characteristic morphologic and immunohistochemical features form the basis of a diagnosis of MASC, the presence of an ETV6-NTRK3 gene fusion is confirmatory. Given its recent recognition the true prognostic import of MASC is not yet clearly defined.

  13. Cyanopeptide analogues: new lead structures for the design and synthesis of new thrombin inhibitors.

    PubMed

    Radau, G; Stürzebecher, J

    2002-11-01

    This contribution deals with the structure-based design and syntheses of the new serine protease inhibitors RA-1001 and RA-1002, which are analogues of the blue-green algae derived cyanopeptide aeruginosin 98-B. Both compounds inhibit thrombin with Ki values of 5.6 microM and 8.7 microM, respectively.

  14. NASA/ESMD Analogue Mission Plans

    NASA Technical Reports Server (NTRS)

    Hoffman, Stephen J.

    2007-01-01

    A viewgraph presentation exploring Earth and its analogues is shown. The topics include: 1) ESMD Goals for the Use of Earth Analogues; 2) Stakeholders Summary; 3) Issues with Current Analogue Situation; 4) Current state of Analogues; 5) External Implementation Plan (Second Step); 6) Recent Progress in Utilizing Analogues; 7) Website Layout Example-Home Page; 8) Website Layout Example-Analogue Site; 9) Website Layout Example-Analogue Mission; 10) Objectives of ARDIG Analog Initiatives; 11) Future Plans; 12) Example: Cold-Trap Sample Return; 13) Example: Site Characterization Matrix; 14) Integrated Analogue Studies-Prerequisites for Human Exploration; and 15) Rating Scale Definitions.

  15. Charge-transfer complexes of Cu(II)/HD analogue in sol gel sensors

    NASA Astrophysics Data System (ADS)

    Brinkley, J. F.; Kirkey, M. L.; Marques, A. D. S.; Lin, C. T.

    2003-01-01

    An optically transparent xerogel encapsulating Cu(II) acetate is fabricated to detect mustard gas (HD) analogues via a charge-transfer mechanism. A fast response (color change from sky blue to canary yellow) is observed for the chlorinated sulfide, and is accompanied by an absorption band at 370-420 nm. MO calculations revealed that the chlorinated HD analogue displays a charge-transfer transition extended from sulfur to chlorine atom. A 1:1 complex of Cu(II)/HD analogue is preferred. For a colorimetric sol-gel detector prepared at pH 3, the detection limit of HD analogue is calibrated at 0.03 μl per 1.5 ml sensor volume.

  16. List 47: blue honeysuckle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This summary presents the descriptions of a newly released blue honeysuckle (Lonicera cerulea L.) cultivar for the List of New Fruit and Nut Cultivars. This blue honeysuckle cultivar was released in Canada in 2012 and has pending Plant Breeder’s Rights Certification with Agriculture Canada. The cult...

  17. Blue Willow Story Plates

    ERIC Educational Resources Information Center

    Fontes, Kris

    2009-01-01

    In the December 1997 issue of "SchoolArts" is a lesson titled "Blue Willow Story Plates" by Susan Striker. In this article, the author shares how she used this lesson with her middle-school students many times over the years. Here, she describes a Blue Willow plate painting project that her students made.

  18. Blue Ocean Thinking

    ERIC Educational Resources Information Center

    Orem, Donna

    2016-01-01

    This article describes a concept called the "blue ocean thinking strategy," developed by W. Chan Kim and Renée Mauborgne, professors at INSEAD, an international graduate school of business in France. The "blue ocean" thinking strategy considers opportunities to create new markets for services, rather than focusing solely on…

  19. Introducing the Blues.

    ERIC Educational Resources Information Center

    Sinclair, Bryan

    2000-01-01

    Discusses the history of the blues and presents a list of resources that are designed to introduce the blues, both as a feeling and as an influential part of American music and culture. Includes picture books and nonfiction for young readers, nonfiction for older readers, Web sites, and compact disks. (LRW)

  20. After Stroke, 'Blue' Light May Help Beat the Blues

    MedlinePlus

    ... Light May Help Beat the Blues Akin to sunlight, it could ward off depression during rehab, study ... facility used "blue" light in its lighting system. Sunlight is humans' largest source of blue-spectrum light, ...

  1. FROM BLUE JEANS TO BLUE GENES

    PubMed Central

    Boon, Laurence M.; Vikkula, Miikka

    2010-01-01

    Cutaneous venous anomalies are common. They are blue in color and vary in size, number and location, and account for the majority of consultations at specialized interdisciplinary clinics for vascular anomalies. Venous lesions are clinically important as they cause pain, dysfunction, destruction of adjacent tissues and esthetic concern. Only resection and sclerotherapy are helpful, although not always curative. Understanding etiopathogenesis could help design animal models and develop novel therapeutic approaches. Dr Mulliken envisioned a project to uncover the genetic basis of an inherited form of venous malformation in a large New England family. Recruitment of two young fellows resulted in a collaborative project that unraveled the searched-for-gene and its mutation. This was an opening for a new era in the field of vascular anomalies. Two blue genes’ mutations were discovered, which account for the majority, if not all, of the inherited forms of venous anomalies, but other genes as well, for rheologically diverse lesions. Differential diagnosis and management has improved, and animal models are being made. This was achieved thanks to Dr Mulliken, who inspired two young investigators in blue jeans to find two blue genes. PMID:19190503

  2. From blue jeans to blue genes.

    PubMed

    Boon, Laurence M; Vikkula, Miikka

    2009-03-01

    Cutaneous venous anomalies are common. They are blue and vary in size, number, and location and account for most consultations at specialized interdisciplinary clinics for vascular anomalies. Venous lesions are clinically important because they cause pain, dysfunction, destruction of adjacent tissues, and esthetic concern. Only resection and sclerotherapy are helpful, although not always curative. Understanding etiopathogenesis could help design animal models and develop novel therapeutic approaches. John B. Mulliken, MD, envisioned a project to uncover the genetic basis of an inherited form of venous malformation in a large New England family. Recruitment of 2 young fellows resulted in a collaborative project that unraveled the searched-for gene and its mutation. This was an opening for a new era in vascular anomalies. Two blue genes' mutations were discovered, which account for most, if not all, of the inherited forms of venous anomalies, but other genes as well, for rheologically diverse lesions. Differential diagnosis and management has improved, and animal models are being made. This was achieved through the help of Dr Mulliken, who inspired 2 young investigators in blue jeans to find 2 blue genes.

  3. Blue ocean strategy.

    PubMed

    Kim, W Chan; Mauborgne, Renée

    2004-10-01

    Despite a long-term decline in the circus industry, Cirque du Soleil profitably increased revenue 22-fold over the last ten years by reinventing the circus. Rather than competing within the confines of the existing industry or trying to steal customers from rivals, Cirque developed uncontested market space that made the competition irrelevant. Cirque created what the authors call a blue ocean, a previously unknown market space. In blue oceans, demand is created rather than fought over. There is ample opportunity for growth that is both profitable and rapid. In red oceans--that is, in all the industries already existing--companies compete by grabbing for a greater share of limited demand. As the market space gets more crowded, prospects for profits and growth decline. Products turn into commodities, and increasing competition turns the water bloody. There are two ways to create blue oceans. One is to launch completely new industries, as eBay did with online auctions. But it's much more common for a blue ocean to be created from within a red ocean when a company expands the boundaries of an existing industry. In studying more than 150 blue ocean creations in over 30 industries, the authors observed that the traditional units of strategic analysis--company and industry--are of limited use in explaining how and why blue oceans are created. The most appropriate unit of analysis is the strategic move, the set of managerial actions and decisions involved in making a major market-creating business offering. Creating blue oceans builds brands. So powerful is blue ocean strategy, in fact, that a blue ocean strategic move can create brand equity that lasts for decades.

  4. From ultraviolet to Prussian blue: a spectral response for the cyanotype process and a safe educational activity to explain UV exposure for all ages.

    PubMed

    Turner, J; Parisi, A V; Downs, N; Lynch, M

    2014-12-01

    Engaging students and the public in understanding UV radiation and its effects is achievable using the real time experiment that incorporates blueprint paper, an "educational toy" that is a safe and easy demonstration of the cyanotype chemical process. The cyanotype process works through the presence of UV radiation. The blueprint paper was investigated to be used as not only engagement in discussion for public outreach about UV radiation, but also as a practical way to introduce the exploration of measurement of UV radiation exposure and as a consequence, digital image analysis. Tests of print methods and experiments, dose response, spectral response and dark response were investigated. Two methods of image analysis for dose response calculation are provided using easy to access software and two methods of pixel count analysis were used to determine spectral response characteristics. Variation in manufacture of the blueprint paper product indicates some variance between measurements. Most importantly, as a result of this investigation, a preliminary spectral response range for the radiation required to produce the cyanotype reaction is presented here, which has until now been unknown.

  5. Mongolian blue spots

    MedlinePlus

    ... bruises. This can raise a question about possible child abuse. It is important to recognize that Mongolian blue ... Elsevier Saunders; 2011:chap 11. Read More Benign Child abuse - physical Rashes Review Date 4/14/2015 Updated ...

  6. Mongolian blue spots (image)

    MedlinePlus

    Mongolian blue spots are flat bluish- to bluish-gray skin markings commonly appearing at birth or shortly ... back and also can appear on the shoulders. Mongolian spots are benign and are not associated with ...

  7. Methylene blue test

    MedlinePlus

    Methemoglobinemia - methylene blue test ... No special preparation is required for this test. ... which are genetic (problem with your genes). This test is used to tell the difference between methemoglobinemia ...

  8. Blue Ribbon Panel Report

    Cancer.gov

    An NCI Cancer Currents blog by the NCI acting director thanking the cancer community for contributing to the Cancer Moonshot Blue Ribbon Panel report, which was presented to the National Cancer Advisory Board on September 7.

  9. Atypical cellular blue nevus or malignant blue nevus?*

    PubMed Central

    Daltro, Luise Ribeiro; Yaegashi, Lygia Bertalha; Freitas, Rodrigo Abdalah; Fantini, Bruno de Carvalho; Souza, Cacilda da Silva

    2017-01-01

    Blue nevus is a benign melanocytic lesion whose most frequent variants are dendritic (common) blue nevus and cellular blue nevus. Atypical cellular blue nevus presents an intermediate histopathology between the typical and a rare variant of malignant blue nevus/melanoma arising in a cellular blue nevus. An 8-year-old child presented a pigmented lesion in the buttock since birth, but with progressive growth in the last two years. After surgical excision, histopathological examination revealed atypical cellular blue nevus. Presence of mitoses, ulceration, infiltration, cytological atypia or necrosis may occur in atypical cellular blue nevus, making it difficult to differentiate it from melanoma. The growth of blue nevus is unusual and considered of high-risk for malignancy, being an indicator for complete resection and periodic follow-up of these patients. PMID:28225968

  10. Neuronal Analogues of Conditioning Paradigms

    DTIC Science & Technology

    1984-04-24

    Although the mechanisms of interneuronal communication have been well established, the changes underlying most forms of learning have thus far eluded...stimulating electrodes on one of the connectives was adjusted so as to produce a small excitatory postsynaptic potential ( EPSP ) in the impaled cell...two stimuli would constitute a neuronal analogue of conditioning by producing an increased EPSP in response to the test stimulus alone. If so, then

  11. Substrate analogues for isoprenoid enzymes

    SciTech Connect

    Stremler, K.E.

    1987-01-01

    Diphosphonate analogues of geranyl diphosphate, resistant to degradation by phosphatases, were found to be alternate substrates for the reaction with farnesyl diphosphate synthetase isolated from avian liver. The difluoromethane analogue was shown to be the better alternate substrate, in agreement with solvolysis results which indicate that the electronegativity of the difluoromethylene unit more closely approximates that of the normal bridging oxygen. The usefulness of the C/sub 10/ difluoro analogue, for detecting low levels of isoprenoid enzymes in the presence of high levels of phosphatase activity, was demonstrated with a cell-free preparation from lemon peel. A series of C/sub 5/ through C/sub 15/ homoallylic and allylic diphosphonates, as well as two 5'-nucleotide diphosphonates, was prepared in high overall yield using the activation-displacement sequence. Radiolabeled samples of several of the allylic diphosphonates were prepared with tritium located at C1. A series of geraniols, stereospecifically deuterated at C1, was prepared. The enantiomeric purities and absolute configurations were determined by derivatization as the mandelate esters for analysis by /sup 1/H NMR. The stereochemistry of the activation-displacement sequence was examined using C1-deuterated substrates.

  12. Nile Blue derivatives as lysosomotropic photosensitizers

    NASA Astrophysics Data System (ADS)

    Lin, Chi-Wei; Shulok, Janine R.; Kirley, S. D.; Cincotta, Louis; Foley, James W.

    1991-06-01

    The benzophenoxazines, including several Nile blue analogues, are a unique group of dyes that localize selectively in animal tumors. Chemical modifications of Nile blue A can yield derivatives with high 1O2 quantum yields. These derivatives represent a group of potentially effective photosensitizers for selective phototherapy of malignant tumors. In vitro evaluation of these derivatives has indicated that those with high 1O2 yields are very effective in mediating the photocytotoxicity of tumor cells. This photodynamic effect is most likely mediated through the action of 1O2, since photoirradiation under D2O enhanced and under hypoxic conditions diminished the photocytotoxic action. The subcellular localization of these photosensitizers in bladder tumor cells in culture was examined by light and fluorescence microscopies as well as by histochemical and biochemical studies. The results indicate that these dyes are localized primarily in the lysosome. The cellular uptake and retention of these dyes is energy- and pH-dependent. Agents such as nigericin, which alter the transmembrane pH gradient, reduced uptake and enhanced efflux of the dyes, while agents such as valinomycin, which reduce cellular membrane potential, had no effect on the uptake. These findings are consistent with having ion-trapping as the mechanism for the uptake of these dyes. Photoirradiation of sensitizer-treated cells obliterated lysosomes in a light-dose and drug-dose dependent fashion. Release of the hydrolytic enzymes may be the main cause for subsequent cell death since the cytolytic effect was reduced by a specific inhibitor of lysosomal proteolytic enzyme. A lysosomotropic photosensitization mechanism is therefore proposed for the photocytotoxic action of the Nile blue derivatives. This mechanism may provide an approach to the development of new photosensitizers for the effective and selective destruction of malignant tumors.

  13. [Blue light and eye health].

    PubMed

    Zou, Leilei; Dai, Jinhui

    2015-01-01

    Blue light, with the wavelength between 400 nm and 500 nm, has caused public concern because of the injury to the retinal cells. Meanwhile, it is important in circadian rhythm regulation, scotopic vision and ocular growth. Is the blue light safe? Should it be eliminated from the daily life? Here we review the effect and safety of the blue light.

  14. Learning the Blues. [Lesson Plan].

    ERIC Educational Resources Information Center

    2001

    This lesson introduces students to the "blues," one of the most distinctive and influential elements of African-American musical tradition. With this lesson plan, students can take a virtual field trip to Memphis, Tennessee, one of the prominent centers of blues activities, and explore the history of the blues in the work of W. C. Handy…

  15. The Blue Emu

    NASA Technical Reports Server (NTRS)

    Descalzi, Doug; Gillett, John; Gordon, Carlton; Keener, ED; Novak, Ken; Puente, Laura

    1993-01-01

    The primary goal in designing the Blue Emu was to provide an airline with a cost efficient and profitable means of transporting passengers between the major cities in Aeroworld. The design attacks the market where a demand for inexpensive transportation exists and for this reason the Blue Emu is an attractive investment for any airline. In order to provide a profitable aircraft, special attention was paid to cost and economics. For example, in manufacturing, simplicity was stressed in structural design to reduce construction time and cost. Aerodynamic design employed a tapered wing which reduced the induced drag coefficient while also reducing the weight of the wing. Even the propulsion system was selected with cost effectiveness in mind, yet also to maintain the marketability of the aircraft. Thus, in every aspect of the design, consideration was given to economics and marketability of the final product.

  16. Voyager 1 'Blue Movie'

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This is the original Voyager 'Blue Movie' (so named because it was built from Blue filter images). It records the approach of Voyager 1 during a period of over 60 Jupiter days. Notice the difference in speed and direction of the various zones of the atmosphere. The interaction of the atmospheric clouds and storms shows how dynamic the Jovian atmosphere is.

    As Voyager 1 approached Jupiter in 1979, it took images of the planet at regular intervals. This sequence is made from 66 images taken once every Jupiter rotation period (about 10 hours). This time-lapse movie uses images taken every time Jupiter longitude 68W passed under the spacecraft. These images were acquired in the Blue filter from Jan. 6 to Feb. 3 1979. The spacecraft flew from 58 million kilometers to 31 million kilometers from Jupiter during that time.

    This time-lapse movie was produced at JPL by the Image Processing Laboratory in 1979.

  17. Blue metal-poor stars

    NASA Astrophysics Data System (ADS)

    Preston, George W.; Sneden, Christopher

    2004-12-01

    We review the discovery of blue metal-poor (BMP) stars and the resolution of this population into blue stragglers and intermediate-age Main-Sequence stars by use of binary fractions. We show that the specific frequencies of blue stragglers in the halo field and in globular clusters differ by an order of magnitude. We attribute this difference to the different modes of production of these two populations. We report carbon and s-process enrichment among very metal-poor field blue stragglers and discuss how this result can be used to further resolve field blue stragglers into groups formed during RGB and AGB evolution of their erstwhile primary companions.

  18. Ecstasy analogues found in cacti.

    PubMed

    Bruhn, Jan G; El-Seedi, Hesham R; Stephanson, Nikolai; Beck, Olof; Shulgin, Alexander T

    2008-06-01

    Human interest in psychoactive phenethylamines is known from the use of mescaline-containing cacti and designer drugs such as Ecstasy. From the alkaloid composition of cacti we hypothesized that substances resembling Ecstasy might occur naturally. In this article we show that lophophine, homopiperonylamine and lobivine are new minor constituents of two cactus species, Lophophora williamsii (peyote) and Trichocereus pachanoi (San Pedro). This is the first report of putatively psychoactive phenethylamines besides mescaline in these cacti. A search for further biosynthetic analogues may provide new insights into the structure-activity relationships of mescaline. An intriguing question is whether the new natural compounds can be called "designer drugs."

  19. FUNCTION GENERATOR FOR ANALOGUE COMPUTERS

    DOEpatents

    Skramstad, H.K.; Wright, J.H.; Taback, L.

    1961-12-12

    An improved analogue computer is designed which can be used to determine the final ground position of radioactive fallout particles in an atomic cloud. The computer determines the fallout pattern on the basis of known wind velocity and direction at various altitudes, and intensity of radioactivity in the mushroom cloud as a function of particle size and initial height in the cloud. The output is then displayed on a cathode-ray tube so that the average or total luminance of the tube screen at any point represents the intensity of radioactive fallout at the geographical location represented by that point. (AEC)

  20. Template polymerization of nucleotide analogues

    NASA Technical Reports Server (NTRS)

    Orgel, L. E.

    1991-01-01

    Recent work on the template-directed reactions of the natural D-nucleotides has made it clear that l-nucleotides and nucleotide-like derivatives of other sugars would strongly inhibit the formation of long oligonucleotides. Consequently, attention is focusing on molecules simpler than nucleotides that might have acted as monomers of an information transfer system. We have begun a general exploration of the template directed reactions of diverse peptide analogues. I will present work by Dr. Taifeng Wu on oxidative oligomerization of phosphorothioates and of Dr. Mary Tohidi on the cyclic polymerization of nucleoside and related cyclic pyrophosphates.

  1. Choline Analogues in Malaria Chemotherapy

    PubMed Central

    Peyrottes, Suzanne; Caldarelli, Sergio; Wein, Sharon; Périgaud, Christian; Pellet, Alain; Vial, Henri

    2012-01-01

    Emerging resistance against well-established anti-malaria drugs warrants the introduction of new therapeutic agents with original mechanisms of action. Inhibition of membrane-based phospholipid biosynthesis, which is crucial for the parasite, has thus been proposed as a novel and promising therapeutic strategy. This review compiles literature concerning the design and study of choline analogues and related cation derivatives as potential anti-malarials. It covers advances achieved over the last two decades and describes: the concept validation, the design and selection of a clinical candidate (Albitiazolium), back-up derivatives while also providing insight into the development of prodrug approaches. PMID:22607139

  2. Electrostatic evaluation of isosteric analogues

    NASA Astrophysics Data System (ADS)

    Sayle, Roger; Nicholls, Anthony

    2006-04-01

    A method is presented for enumerating a large number of isosteric analogues of a ligand from a known protein-ligand complex structure and then rapidly calculating an estimate of their binding energies. This approach takes full advantage of the observed crystal structure, by reusing the atomic co-ordinates determined experimentally for one ligand, to approximate those of similar compounds that have approximately the same shape. By assuming that compounds with similar shapes adopt similar binding poses, and that entropic and protein flexibility effects are approximately constant across such an isosteric series ("the frozen ligand approximation"), it is possible to order their binding affinities relatively accurately. Additionally, the constraint that the atomic coordinates are invariant allows for a dramatic simplification in the Poisson-Boltzmann method used to calculation the electrostatic component of the binding energy. This algorithmic improvement allows for the calculation of tens of thousands of binding energies per second for drug-like molecules, enabling this technique to be used in screening large virtual libraries of isosteric analogues. Most significantly, this procedure is shown to be able to reproduce SAR effects of subtle medicinal chemistry substitutions. Finally, this paper reports the results of the proposed methodology on␣seven model systems; dihydrofolate reductase, Lck␣kinase, ribosome inactivating protein, l-arabinose binding protein, neuraminidase, HIV-1 reverse transcriptase and COX-2.

  3. The Valles natural analogue project

    SciTech Connect

    Stockman, H.; Krumhansl, J.; Ho, C.; McConnell, V.

    1994-12-01

    The contact between an obsidian flow and a steep-walled tuff canyon was examined as an analogue for a highlevel waste repository. The analogue site is located in the Valles Caldera in New Mexico, where a massive obsidian flow filled a paleocanyon in the Battleship Rock tuff. The obsidian flow provided a heat source, analogous to waste panels or an igneous intrusion in a repository, and caused evaporation and migration of water. The tuff and obsidian samples were analyzed for major and trace elements and mineralogy by INAA, XRF, X-ray diffraction; and scanning electron microscopy and electron microprobe. Samples were also analyzed for D/H and {sup 39}Ar/{sup 4O} isotopic composition. Overall,the effects of the heating event seem to have been slight and limited to the tuff nearest the contact. There is some evidence of devitrification and migration of volatiles in the tuff within 10 meters of the contact, but variations in major and trace element chemistry are small and difficult to distinguish from the natural (pre-heating) variability of the rocks.

  4. Heteroatom-Containing Porphyrin Analogues.

    PubMed

    Chatterjee, Tamal; Shetti, Vijayendra S; Sharma, Ritambhara; Ravikanth, Mangalampalli

    2017-02-22

    The heteroatom-containing porphyrin analogues or core-modified porphyrins that resulted from the replacement of one or two pyrrole rings with other five-membered heterocycles such as furan, thiophene, selenophene, tellurophene, indene, phosphole, and silole are highly promising macrocycles and exhibit quite different physicochemical properties compared to regular azaporphyrins. The properties of heteroporphyrins depend on the nature and number of different heterocycle(s) present in place of pyrrole ring(s). The heteroporphyrins provide unique and unprecedented coordination environments for metals. Unlike regular porphyrins, the monoheteroporphyrins are known to stabilize metals in unusual oxidation states such as Cu and Ni in +1 oxidation states. The diheteroporphyrins, which are neutral macrocycles without ionizable protons, also showed interesting coordination chemistry. Thus, significant progress has been made in last few decades on core-modified porphyrins in terms of their synthesis, their use in building multiporphyrin arrays for light-harvesting applications, their use as ligands to form interesting metal complexes, and also their use for several other studies. The synthetic methods available in the literature allow one to prepare mono- and diheteroporphyrins and their functionalized derivatives, which were used extensively to prepare several covalent and noncovalent heteroporphyrin-based multiporphyrin arrays. The methods are also developed to synthesize different hetero analogues of porphyrin derivatives such as heterocorroles, heterochlorins, heterocarbaporphyrinoids, heteroatom-substituted confused porphyrins, and so on. This Review summarizes the key developments that have occurred in heteroporphyrin chemistry over the last four decades.

  5. The Blue Marble

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This spectacular Moderate Resolution Imaging Spectroradiometer (MODIS) 'blue marble' image is based on the most detailed collection of true-color imagery of the entire Earth to date. Using a collection of satellite-based observations, scientists and visualizers stitched together months of observations of the land surface, oceans, sea ice, and clouds into a seamless, true-color mosaic of every square kilometer (.386 square mile) of our planet. Most of the information contained in this image came from MODIS, illustrating MODIS' outstanding capacity to act as an integrated tool for observing a variety of terrestrial, oceanic, and atmospheric features of the Earth. The land and coastal ocean portions of this image is based on surface observations collected from June through September 2001 and combined, or composited, every eight days to compensate for clouds that might block the satellite's view on any single day. Global ocean color (or chlorophyll) data was used to simulate the ocean surface. MODIS doesn't measure 3-D features of the Earth, so the surface observations were draped over topographic data provided by the U.S. Geological Survey EROS Data Center. MODIS observations of polar sea ice were combined with observations of Antarctica made by the National Oceanic and Atmospheric Administration's AVHRR sensor-the Advanced Very High Resolution Radiometer. The cloud image is a composite of two days of MODIS imagery collected in visible light wavelengths and a third day of thermal infra-red imagery over the poles. A large collection of imagery based on the blue marble in a variety of sizes and formats, including animations and the full (1 km) resolution imagery, is available at the Blue Marble page. Image by Reto Stockli, Render by Robert Simmon. Based on data from the MODIS Science Team

  6. Accumulation of 20 elements in great cormorant (Phalacrocorax carbo) and its main prey, common carp (Cyprinus carpio) and Prussian carp (Carassius gibelio).

    PubMed

    Skoric, Stefan; Visnjić-Jeftic, Zeljka; Jaric, Ivan; Djikanovic, Vesna; Mickovic, Branislav; Nikcevic, Miroslav; Lenhardt, Mirjana

    2012-06-01

    In this study, 20 heavy metals and trace elements (Al, As, B, Ba, Cd, Co, Cr, Cu, Fe, Hg, Li, Mg, Mn, Mo, Ni, Pb, Si, Se, Sr and Zn) were analyzed in different tissues (muscle, liver, intestine, feather and bone) of the great cormorant (Phalacrocorax carbo) and in different tissues (muscle, liver, gills, kidney and gonad) of their main prey (common carp-Cyprinus carpio and Prussian carp-Carassius gibelio) during the nesting season. Cormorant and fish specimens were collected at the Ečka Fishing Farm (Serbia) and from the nearby river. Principal components analysis (PCA) showed that cormorant livers were differentiated from other four tissues by higher concentrations of Hg, Fe, Cu and Mo, feathers by higher concentrations of Al and Si, and bones by higher concentrations of Sr and Mg. Differentiation among the three age classes of cormorants was observed only with regard to elemental concentrations in their feathers: subadult cormorants were differentiated by higher Hg and Zn concentrations, while the adults were separated by higher concentrations of Fe. In comparison with their prey (common carp and Prussian carp) cormorants were differentiated by higher concentrations of Fe, Hg and Cu in the muscle. Toxic mercury concentrations above 4μgg(-1)dw were determined in the liver of juvenile cormorants, as well as in the liver and feathers of subadults. Hg concentrations were significantly correlated among all studied tissues. Cormorant had significantly higher concentrations of Fe and Hg in muscle and liver than two studied fish species.

  7. Blue upconversion thulium laser

    NASA Astrophysics Data System (ADS)

    Nguyen, Dinh C.; Faulkner, George E.; Weber, Michael E.; Dulick, Michael

    1990-04-01

    We report a blue emission upconversion solid-state laser based on Tm3+:YLF. Under double resonance excitation at 780.8 nm (near-ir) and 648.8 nm (red), the Tm3+ ion is sequentially excited from the 3H6 ground state to the 1D2 excited state through the 3H4 intermediate level. The laser output at 450 and 453 nm corresponds to the 1D2 -> 3F4 transitions of Tm3+ ions in YLF.

  8. Keratoglobus and blue sclera.

    PubMed

    Biglan, A W; Brown, S I; Johnson, B L

    1977-02-01

    Five patients from two families had similar features including keratoglobus, blue scleras, hyperextensibility of the hand, wrist, and ankle joints, sensorineural conduction hearing alterations, and mottling of the teeth. Keratoglobus had been observed in all patients at, or shortly after, birth. Corneal perforations developed in seven of the ten eyes after minimal trauma. Repair of these perforations was complicated by the extremely thin corneas and six eyes had to be either enucleated or eviscerated. Histopathological examination of two of the enucleated eyes showed the corneal stromas of both eyes to be estremely thin, Bowman's membrane was absent, and Descemet's membrane was unusually thick. This condition has an autosomal-recessive inheritance pattern.

  9. CO2 Capture with Enzyme Synthetic Analogue

    SciTech Connect

    Cordatos, Harry

    2010-11-08

    Overview of an ongoing, 2 year research project partially funded by APRA-E to create a novel, synthetic analogue of carbonic anhydrase and incorporate it into a membrane for removal of CO2 from flue gas in coal power plants. Mechanism background, preliminary feasibility study results, molecular modeling of analogue-CO2 interaction, and program timeline are provided.

  10. Macrolactam analogues of macrolide natural products.

    PubMed

    Hügel, Helmut M; Smith, Andrew T; Rizzacasa, Mark A

    2016-12-07

    The chemical modification of macrolide natural products into aza- or lactam analogues is a strategy employed to improve their metabolic stability and biological activity. The methods for the synthesis of several lactam analogues of macrolide natural products are highlighted and aspects of their biological properties presented.

  11. The future of somatostatin analogue therapy.

    PubMed

    Stewart, P M; James, R A

    1999-10-01

    Since its discovery almost 30 years ago, the mode of action and therapeutic applications of somatostatin have been defined. In particular the cloning and characterization of somatostatin receptor subtypes has facilitated the development of high affinity analogues. In the context of pituitary disease, long-acting somatostatin analogues (octreotide, lanreotide) have been used to treat a variety of pituitary tumours but are most efficacious for the treatment of GH and TSH-secreting adenomas. In patients with acromegaly, depot preparations of these analogues are administered intramuscularly every 10-28 days and provide consistent suppression of GH levels to < 5 mU/l in approximately 50-65% of all cases. Even more specific somatostatin receptor analogues are under development. Finally, radiolabelled somatostatin analogue scintigraphy and, in larger doses, therapy, are now established tools in the evaluation and treatment of neuroendocrine tumours.

  12. Continuous analogues of matrix factorizations

    PubMed Central

    Townsend, Alex; Trefethen, Lloyd N.

    2015-01-01

    Analogues of singular value decomposition (SVD), QR, LU and Cholesky factorizations are presented for problems in which the usual discrete matrix is replaced by a ‘quasimatrix’, continuous in one dimension, or a ‘cmatrix’, continuous in both dimensions. Two challenges arise: the generalization of the notions of triangular structure and row and column pivoting to continuous variables (required in all cases except the SVD, and far from obvious), and the convergence of the infinite series that define the cmatrix factorizations. Our generalizations of triangularity and pivoting are based on a new notion of a ‘triangular quasimatrix’. Concerning convergence of the series, we prove theorems asserting convergence provided the functions involved are sufficiently smooth. PMID:25568618

  13. Fully analogue photonic reservoir computer.

    PubMed

    Duport, François; Smerieri, Anteo; Akrout, Akram; Haelterman, Marc; Massar, Serge

    2016-03-03

    Introduced a decade ago, reservoir computing is an efficient approach for signal processing. State of the art capabilities have already been demonstrated with both computer simulations and physical implementations. If photonic reservoir computing appears to be promising a solution for ultrafast nontrivial computing, all the implementations presented up to now require digital pre or post processing, which prevents them from exploiting their full potential, in particular in terms of processing speed. We address here the possibility to get rid simultaneously of both digital pre and post processing. The standalone fully analogue reservoir computer resulting from our endeavour is compared to previous experiments and only exhibits rather limited degradation of performances. Our experiment constitutes a proof of concept for standalone physical reservoir computers.

  14. Fully analogue photonic reservoir computer

    PubMed Central

    Duport, François; Smerieri, Anteo; Akrout, Akram; Haelterman, Marc; Massar, Serge

    2016-01-01

    Introduced a decade ago, reservoir computing is an efficient approach for signal processing. State of the art capabilities have already been demonstrated with both computer simulations and physical implementations. If photonic reservoir computing appears to be promising a solution for ultrafast nontrivial computing, all the implementations presented up to now require digital pre or post processing, which prevents them from exploiting their full potential, in particular in terms of processing speed. We address here the possibility to get rid simultaneously of both digital pre and post processing. The standalone fully analogue reservoir computer resulting from our endeavour is compared to previous experiments and only exhibits rather limited degradation of performances. Our experiment constitutes a proof of concept for standalone physical reservoir computers. PMID:26935166

  15. Blue ocean leadership.

    PubMed

    Kim, W Chan; Mauborgne, Renée

    2014-05-01

    Ten years ago, two INSEAD professors broke ground by introducing "blue ocean strategy," a new model for discovering uncontested markets that are ripe for growth. In this article, they apply their concepts and tools to what is perhaps the greatest challenge of leadership: closing the gulf between the potential and the realized talent and energy of employees. Research indicates that this gulf is vast: According to Gallup, 70% of workers are disengaged from their jobs. If companies could find a way to convert them into engaged employees, the results could be transformative. The trouble is, managers lack a clear understanding of what changes they could make to bring out the best in everyone. Here, Kim and Mauborgne offer a solution to that problem: a systematic approach to uncovering, at each level of the organization, which leadership acts and activities will inspire employees to give their all, and a process for getting managers throughout the company to start doing them. Blue ocean leadership works because the managers' "customers"-that is, the people managers oversee and report to-are involved in identifying what's effective and what isn't. Moreover, the approach doesn't require leaders to alter who they are, just to undertake a different set of tasks. And that kind of change is much easier to implement and track than changes to values and mind-sets.

  16. Blue diffuse dwarf galaxies: a clearer picture

    NASA Astrophysics Data System (ADS)

    James, Bethan L.; Koposov, Sergey E.; Stark, Daniel P.; Belokurov, Vasily; Pettini, Max; Olszewski, Edward W.; McQuinn, Kristen B. W.

    2017-03-01

    The search for chemically unevolved galaxies remains prevalent in the nearby Universe, mostly because these systems provide excellent proxies for exploring in detail the physics of high-z systems. The most promising candidates are extremely metal-poor galaxies (XMPs), i.e. galaxies with <1/10 solar metallicity. However, due to the bright emission-line-based search criteria traditionally used to find XMPs, we may not be sampling the full XMP population. In 2014, we reoriented this search using only morphological properties and uncovered a population of ∼150 'blue diffuse dwarf (BDD) galaxies', and published a sub-sample of 12 BDD spectra. Here, we present optical spectroscopic observations of a larger sample of 51 BDDs, along with their Sloan Digital Sky Survey (SDSS) photometric properties. With our improved statistics, we use direct-method abundances to confirm that BDDs are chemically unevolved (7.43 < 12 + log(O/H) < 8.01), with ∼20 per cent of our sample classified as being XMP galaxies, and find that they are actively forming stars at rates of ∼1-33 × 10-2 M⊙ yr-1 in H II regions randomly embedded in a blue, low-surface-brightness continuum. Stellar masses are calculated from population synthesis models and estimated to be in the range log (M*/M⊙) ≃ 5-9. Unlike other low-metallicity star-forming galaxies, BDDs are in agreement with the mass-metallicity relation at low masses, suggesting that they are not accreting large amounts of pristine gas relative to their stellar mass. BDD galaxies appear to be a population of actively star-forming dwarf irregular (dIrr) galaxies which fall within the class of low-surface-brightness dIrr galaxies. Their ongoing star formation and irregular morphology make them excellent analogues for galaxies in the early Universe.

  17. Negative thermal expansion in the Russian blue analog Zn3[Fe(CN)6]2: x-ray diffraction and neutron vibrational studies

    SciTech Connect

    Nakotte, Heinz; Daemen, Luke; Adak, Sourav

    2009-01-01

    The cubic Prussian Blue (PB) analog, Zn{sub 3} [Fe(CN){sub 6}]{sub 2}, has been studied by X-ray powder diffraction and inelastic neutron scattering (INS). X-ray data collected at 300 and 84 K revealed negative thermal expansion (NTE) behavior for this material. The NTE coefficient was found to be -31.1 x 10{sup -6} K{sup -1}. The neutron vibrational spectrum for Zn{sub 3}[Fe(CN){sub 6}]{sub 2}.xH{sub 2}O, was studied in detail. The INS spectrum showed well-defined, well-separated bands corresponding to the stretching of and deformation modes of the Fe and Zn octahedra, all below 800 cm{sup -1}.

  18. Plant Volatile Analogues Strengthen Attractiveness to Insect

    PubMed Central

    Sun, Yufeng; Yu, Hao; Zhou, Jing-Jiang; Pickett, John A.; Wu, Kongming

    2014-01-01

    Green leaf bug Apolygus lucorum (Meyer-Dür) is one of the major pests in agriculture. Management of A. lucorum was largely achieved by using pesticides. However, the increasing population of A. lucorum since growing Bt cotton widely and the increased awareness of ecoenvironment and agricultural product safety makes their population-control very challenging. Therefore this study was conducted to explore a novel ecological approach, synthetic plant volatile analogues, to manage the pest. Here, plant volatile analogues were first designed and synthesized by combining the bioactive components of β-ionone and benzaldehyde. The stabilities of β-ionone, benzaldehyde and analogue 3 g were tested. The electroantennogram (EAG) responses of A. lucorum adult antennae to the analogues were recorded. And the behavior assay and filed experiment were also conducted. In this study, thirteen analogues were acquired. The analogue 3 g was demonstrated to be more stable than β-ionone and benzaldehyde in the environment. Many of the analogues elicited EAG responses, and the EAG response values to 3 g remained unchanged during seven-day period. 3 g was also demonstrated to be attractive to A. lucorum adults in the laboratory behavior experiment and in the field. Its attractiveness persisted longer than β-ionone and benzaldehyde. This indicated that 3 g can strengthen attractiveness to insect and has potential as an attractant. Our results suggest that synthetic plant volatile analogues can strengthen attractiveness to insect. This is the first published study about synthetic plant volatile analogues that have the potential to be used in pest control. Our results will support a new ecological approach to pest control and it will be helpful to ecoenvironment and agricultural product safety. PMID:24911460

  19. Pluto’s Blue Haze

    NASA Video Gallery

    The sky on Pluto is blue! Kind of. This is Pluto in an Minute. So it’s not exactly the case that the sky on Pluto is blue, rather, what the New Horizons science team has found in recent images do...

  20. Space analogue studies in Antarctica

    NASA Astrophysics Data System (ADS)

    Lugg, D.; Shepanek, M.

    1999-09-01

    Medical research has been carried out on the Australian National Antarctic Research Expeditions (ANARE) for 50 years. As an extension of this program collaborative Australian/United States research on immunology, microbiology, psychology and remote medicine has produced important data and insight on how humans adapt to the stress of extreme isolation, confinement and the harsh environment of Antarctica. An outstanding analogue for the isolation and confinement of space missions (especially planetary outposts), ANARE has been used as an international research platform by Australia and the United States since 1993. Collaborative research has demonstrated a lowered responsiveness of the immune system under the isolation and confinement of Antarctic winter-over; a reduction of almost 50% in T cell proliferation to mltogen phytohaemogglutinin, as well as changes in latent herpesvirus states and the expansion of the polyclonal latent Epstein-Barr virus infected B cell populations. Although no clinically significant disease has been found to result from these immune changes, research is currently assessing the effects of psychological factors on the immune system. This and associated research performed to date and its relevance to both organisations is discussed, and comment made on possible extensions to the program in both medical and other fields.

  1. Condensed matter analogues of cosmology

    NASA Astrophysics Data System (ADS)

    Kibble, Tom; Srivastava, Ajit

    2013-10-01

    It is always exciting when developments in one branch of physics turn out to have relevance in a quite different branch. It would be hard to find two branches farther apart in terms of energy scales than early-universe cosmology and low-temperature condensed matter physics. Nevertheless ideas about the formation of topological defects during rapid phase transitions that originated in the context of the very early universe have proved remarkably fruitful when applied to a variety of condensed matter systems. The mathematical frameworks for describing these systems can be very similar. This interconnection has led to a deeper understanding of the phenomena in condensed matter systems utilizing ideas from cosmology. At the same time, one can view these condensed matter analogues as providing, at least in a limited sense, experimental access to the phenomena of the early universe for which no direct probe is possible. As this special issue well illustrates, this remains a dynamic and exciting field. The basic idea is that when a system goes through a rapid symmetry-breaking phase transition from a symmetric phase into one with spontaneously broken symmetry, the order parameter may make different choices in different regions, creating domains that when they meet can trap defects. The scale of those domains, and hence the density of defects, is constrained by the rate at which the system goes through the transition and the speed with which order parameter information propagates. This is what has come to be known as the Kibble-Zurek mechanism. The resultant scaling laws have now been tested in a considerable variety of different systems. The earliest experiments illustrating the analogy between cosmology and condensed matter were in liquid crystals, in particular on the isotropic-to-nematic transition, primarily because it is very easy to induce the phase transition (typically at room temperature) and to image precisely what is going on. This field remains one of the

  2. Space analogue studies in Antarctica.

    PubMed

    Lugg, D; Shepanek, M

    1999-01-01

    Medical research has been carried out on the Australian National Antarctic Research Expeditions (ANARE) for 50 years. As an extension of this program collaborative Australian/United States research on immunology, microbiology, psychology and remote medicine has produced important data and insight on how humans adapt to the stress of extreme isolation, confinement and the harsh environment of Antarctica. An outstanding analogue for the isolation and confinement of space missions (especially planetary outposts), ANARE has been used as an international research platform by Australia and the United States since 1993. Collaborative research has demonstrated a lowered responsiveness of the immune system under the isolation and confinement of Antarctic winter-over; a reduction of almost 50% in T cell proliferation to mitogen phytohaemogglutinin, as well as changes in latent herpesvirus states and the expansion of the polyclonal latent Epstein-Barr virus infected B cell populations. Although no clinically significant disease has been found to result from these immune changes, research is currently assessing the effects of psychological factors on the immune system. This and associated research performed to date and its relevance to both organisations is discussed, and comment made on possible extensions to the program in both medical and other fields.

  3. Space analogue studies in Antarctica

    NASA Technical Reports Server (NTRS)

    Lugg, D.; Shepanek, M.

    1999-01-01

    Medical research has been carried out on the Australian National Antarctic Research Expeditions (ANARE) for 50 years. As an extension of this program collaborative Australian/United States research on immunology, microbiology, psychology and remote medicine has produced important data and insight on how humans adapt to the stress of extreme isolation, confinement and the harsh environment of Antarctica. An outstanding analogue for the isolation and confinement of space missions (especially planetary outposts), ANARE has been used as an international research platform by Australia and the United States since 1993. Collaborative research has demonstrated a lowered responsiveness of the immune system under the isolation and confinement of Antarctic winter-over; a reduction of almost 50% in T cell proliferation to mitogen phytohaemogglutinin, as well as changes in latent herpesvirus states and the expansion of the polyclonal latent Epstein-Barr virus infected B cell populations. Although no clinically significant disease has been found to result from these immune changes, research is currently assessing the effects of psychological factors on the immune system. This and associated research performed to date and its relevance to both organisations is discussed, and comment made on possible extensions to the program in both medical and other fields.

  4. Blue metal complex pigments involved in blue flower color

    PubMed Central

    Takeda, Kosaku

    2006-01-01

    The blue pigment of cornflower, protocyanin, has been investigated for a long time, but its precise structure was not entirely explained until recently. The molecular structure of the pigment was recently shown to be a metal complex of six molecules each of anthocyanin and flavone glycoside, with one ferric iron, one magnesium and two calcium ions by X-ray crystallographic analysis. The studies provided the answer to the question posed in the early part of the last century, “why is the cornflower blue and rose red when both flowers contain the same anthocyanin?” This work was achieved on the basis of the results of long years of the studies made by many researchers. In this review, the author focuses on the investigations of the blue metal complex pigments involved in the bluing of flowers, commelinin from Commelina commusis, protocyanin from Centaurea cyanus, protodelphin from Salvia patens and hydrangea blue pigment. PMID:25792777

  5. Blue metal complex pigments involved in blue flower color.

    PubMed

    Takeda, Kosaku

    2006-05-01

    The blue pigment of cornflower, protocyanin, has been investigated for a long time, but its precise structure was not entirely explained until recently. The molecular structure of the pigment was recently shown to be a metal complex of six molecules each of anthocyanin and flavone glycoside, with one ferric iron, one magnesium and two calcium ions by X-ray crystallographic analysis. The studies provided the answer to the question posed in the early part of the last century, "why is the cornflower blue and rose red when both flowers contain the same anthocyanin?" This work was achieved on the basis of the results of long years of the studies made by many researchers. In this review, the author focuses on the investigations of the blue metal complex pigments involved in the bluing of flowers, commelinin from Commelina commusis, protocyanin from Centaurea cyanus, protodelphin from Salvia patens and hydrangea blue pigment.

  6. Mapping Densities in Analogue Laboratory Turbulent Plumes Using Dye Concentration

    NASA Astrophysics Data System (ADS)

    Fisher, M. A.; Kobs-Nawotniak, S. E.

    2014-12-01

    Changing tephra concentration in volcanic eruption columns is difficult to measure in the field due to fluid opacity. The bulk fluid erupted may be higher density than the surrounding atmosphere at the vent and then transition to positive buoyancy through the ingestion and heating of ambient air; thus, the concentration of the plume fluid as it rises is critical to determining whether the material rises in a sustained plume or collapses into a pyroclastic density current. We evaluate the changing concentration of an analogue plume via tracer dye intensity and relate it to plume radius expansion and vent distance. To calibrate our concentration metric, we calculated the density and dye concentration of pre-determined tracer-water mixtures. The density of the solution was directly measured using a micropipette and high precision balance. The calculated density falls within the standard error of the measured density for each step. Five photographs were taken of each concentration using a mounted Ex-FH100 digital camera with identical lighting. Using a MATLAB script, the RGB (Red-Green-Blue) color value was extracted from five pixels located at the same coordinates in each image, confirming that there was no inherent error caused by the camera and that the RGB value was the same across an entire image. We created a color map to convert from the RGB color value of a pixel in an image to its corresponding concentration. This method algorithm can then be applied to an analogue volcanic tank model, using the color variations in the plume eddies to determine the tracer concentration, and thereby density distribution, in the plume.

  7. Glucagonlike Peptide 2 Analogue Teduglutide

    PubMed Central

    Chaturvedi, Lakshmi S.; Basson, Marc D.

    2015-01-01

    IMPORTANCE Short bowel syndrome occurs when a shortened intestine cannot absorb sufficient nutrients or fluids. Teduglutide is a recombinant analogue of human glucagonlike peptide 2 that reduces dependence on parenteral nutrition in patients with short bowel syndrome by promoting enterocytic proliferation, increasing the absorptive surface area. However, enterocyte function depends not only on the number of cells that are present but also on differentiated features that facilitate nutrient absorption and digestion. OBJECTIVE To test the hypothesis that teduglutide impairs human intestinal epithelial differentiation. DESIGN AND SETTING We investigated the effects of teduglutide in the modulation of proliferation and differentiation in human Caco-2 intestinal epithelial cells at a basic science laboratory. This was an in vitro study using Caco-2 cells, a human-derived intestinal epithelial cell line commonly used to model enterocytic biology. EXPOSURE Cells were exposed to teduglutide or vehicle control. MAINOUTCOMESAND MEASURES We analyzed the cell cycle by bromodeoxyuridine incorporation or propidium iodide staining and flow cytometry and measured cell proliferation by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay. We used quantitative reverse transcription–polymerase chain reaction to assay the expression of the enterocytic differentiation markers villin, sucrase-isomaltase, glucose transporter 2 (GLUT2), and dipeptidyl peptidase 4 (DPP-4), as well as that of the putative differentiation signals schlafen 12 (SLFN12) and caudal-related homeobox intestine-specific transcription factor (Cdx2). Villin promoter activity was measured by a luciferase-based assay. RESULTS The MTS assay demonstrated that teduglutide increased cell numbers by a mean (SD) of 10% (2%) over untreated controls at a maximal 500nM (n = 6, P < .05). Teduglutide increased bromodeoxyuridine-positive cells vs untreated controls by a mean (SD

  8. On the mechanical analogue of DNA.

    PubMed

    Yakushevich, Ludmila

    2017-03-01

    The creation of mechanical analogues of biological systems is known as a useful instrument that helps to understand better the dynamical mechanisms of the functioning of living organisms. Mechanical analogues of biomolecules are usually constructed for imitation of their internal mobility, which is one of the most important properties of the molecules. Among the different types of internal motions, angular oscillations of nitrous bases are of special interest because they make a substantial contribution to the base pairs opening that in turn is an important element of the process of the DNA-protein recognition. In this paper, we investigate the possibility to construct a mechanical analogue for imitation of angular oscillations of nitrous bases in inhomogeneous DNA. It is shown that the analogue has the form of a mechanical chain of non-identical pendulums that oscillate in the gravitational field of the Earth and coupled by identical springs. The masses and lengths of pendulums, as well as the distances between neighboring pendulums and the rigidity of springs are calculated. To illustrate the approach, we present the result of construction of the mechanical analogue of the fragment of the sequence of bacteriophage T7D.

  9. Analogue Downscaling of Seasonal Rainfall Forecasts

    NASA Astrophysics Data System (ADS)

    Charles, A. N.; Timbal, B.; Hendon, H.

    2010-12-01

    We have taken an existing statistical downscaling model (SDM), based on meteorological analogues that was developed for downscaling climate change projections (Timbal et al 2009), and applied it in the seasonal forecasting context to produce downscaled rainfall hindcasts from a coupled model seasonal forecast system (POAMA). Downscaling of POAMA forecasts is required to provide seasonal climate information at local scales of interest. Analogue downscaling is a simple technique to generate rainfall forecasts appropriate to the local scale by conditioning on the large scale predicted GCM circulation and the local topography and climate. Analogue methods are flexible and have been shown to produce good results when downscaling 20th century South Eastern Australian rainfall output from climate models. A set of re-forecasts for three month rainfall at 170 observing stations in the South Murray Darling region of Australia were generated using predictors from the POAMA re-forecasts as input for the analogue SDM. The predictors were optimised over a number of different GCMS in previous climate change downscaling studies. Downscaling with the analogue SDM results in predicted rainfall with realistic variance while maintaining the modest predictive skill of the dynamical model. Evaluation of the consistency between the large scale mean of downscaled and direct GCM output precipitation is encouraging.

  10. Birth of the American Force Projection Army: The Impact of Political, Military, and National Culture and Strategic Position on US Efforts to Incorporate a Prussian-Style General Staff System

    DTIC Science & Technology

    2006-06-16

    way. Sir , for what it is worth, it would be my honor to serve under you anytime, anywhere. Finally, to the most important person in my life, Dr...163. 12Trask, 155. 13Rear Admiral French E. Chadwick , The Relations of the United States and Spain: The Spanish-American War (New York, NY...Moltke, Schlieffen and Prussian War Planning. Lillington, NC: Edwards Brothers, 1991. Chadwick , French E., Rear Admiral. The Relations of the

  11. "Clothed in triple blues": sorting out the Italian blues.

    PubMed

    Bimler, David; Uusküla, Mari

    2014-04-01

    Cross-cultural comparisons of color perception and cognition often feature versions of the "similarity sorting" procedure. By interpreting the assignment of two color samples to different groups as an indication that the dissimilarity between them exceeds some threshold, sorting data can be regarded as low-resolution similarity judgments. Here we analyze sorting data from speakers of Italian, Russian, and English, applying multidimensional scaling to delineate the boundaries between perceptual categories while highlighting differences between the three populations. Stimuli were 55 color swatches, predominantly from the blue region. Results suggest that at least two Italian words for "blue" are basic, a similar situation to Russian, in contrast to English where a single "blue" term is basic.

  12. GABAA Receptor Modulation by Etomidate Analogues

    PubMed Central

    Pejo, Ervin; Santer, Peter; Wang, Lei; Dershwitz, Philip; Husain, S. Shaukat; Raines, Douglas E.

    2015-01-01

    Background Etomidate is a highly potent anesthetic agent that is believed to produce hypnosis by enhancing γ-aminobutyric acid type A (GABAA) receptor function. We characterized the GABAA receptor and hypnotic potencies of etomidate analogues. We then used computational techniques to build statistical and graphical models that relate the potencies of these etomidate analogues to their structures in order to identify the specific molecular determinants of potency. Methods GABAA receptor potencies were defined with voltage-clamp electrophysiology using α1β3γ2 receptors harboring a channel mutation (α1(L264T)) that enhances anesthetic sensitivity (n = 36 – 60 measurements per concentration-response curve). The hypnotic potencies of etomidate analogues were defined using a loss of righting reflexes assay in Sprague Dawley rats (n = 9 – 21 measurements per dose-response curve). Three-dimensional quantitative structure-activity relationships were determined in silico using comparative molecular field analysis. Results The GABAA receptor and hypnotic potencies of etomidate and the etomidate analogues ranged by 91-fold and 53-fold, respectively. These potency measurements were significantly correlated (r2 = 0.72), but neither measurement correlated with drug hydrophobicity (r2 = 0.019 and 0.005, respectively). Statistically significant and predictive comparative molecular field analysis models were generated and a pharmacophore model was built that revealed both the structural elements in etomidate analogues associated with high potency and the interactions that these elements make with the etomidate binding site. Conclusion There are multiple specific structural elements in etomidate and etomidate analogues that mediate GABAA receptor modulation. Modifying any one element can alter receptor potency by an order of magnitude or more. PMID:26691905

  13. Classical Simulated Annealing Using Quantum Analogues

    NASA Astrophysics Data System (ADS)

    La Cour, Brian R.; Troupe, James E.; Mark, Hans M.

    2016-08-01

    In this paper we consider the use of certain classical analogues to quantum tunneling behavior to improve the performance of simulated annealing on a discrete spin system of the general Ising form. Specifically, we consider the use of multiple simultaneous spin flips at each annealing step as an analogue to quantum spin coherence as well as modifications of the Boltzmann acceptance probability to mimic quantum tunneling. We find that the use of multiple spin flips can indeed be advantageous under certain annealing schedules, but only for long anneal times.

  14. Insulin analogues: action profiles beyond glycaemic control.

    PubMed

    Eckardt, Kristin; Eckel, Jürgen

    2008-02-01

    A variety of studies have documented significant improvements in the treatment of type 1 and 2 diabetes after the introduction of artificial insulins. This review gives an overview of insulin analogues which are currently approved for therapeutical use. Clinical data regarding the efficiency to control blood glucose level as well as improving HbA1c level in comparison to conventional insulin preparations in type 1 and 2 diabetic patients are summarized. Furthermore, special features of insulin analogues regarding their signalling properties are discussed with focus on the proliferative effects of insulin glargine as well as some recent data of insulin detemir.

  15. Blue News Update: BODIPY-GTP Binds to the Blue-Light Receptor YtvA While GTP Does Not

    PubMed Central

    Schmieder, Peter

    2012-01-01

    Light is an important environmental factor for almost all organisms. It is mainly used as an energy source but it is also a key factor for the regulation of multiple cellular functions. Light as the extracellular stimulus is thereby converted into an intracellular signal by photoreceptors that act as signal transducers. The blue-light receptor YtvA, a bacterial counterpart of plant phototropins, is involved in the stress response of Bacillus subtilis. The mechanism behind its activation, however, remains unknown. It was suggested based on fluorescence spectroscopic studies that YtvA function involves GTP binding and that this interaction is altered by absorption of light. We have investigated this interaction by several biophysical methods and show here using fluorescence spectroscopy, ITC titrations, and three NMR spectroscopic assays that while YtvA interacts with BODIPY-GTP as a fluorescent GTP analogue originally used for the detection of GTP binding, it does not bind GTP. PMID:22247770

  16. The photoinduced transformation of fluorescent DNA base analogue tC triggers DNA melting.

    PubMed

    Preus, Søren; Jønck, Søren; Pittelkow, Michael; Dierckx, Anke; Karpkird, Thitinun; Albinsson, Bo; Wilhelmsson, L Marcus

    2013-08-01

    While fluorescent analogues of the canonical nucleobases have proven to be highly valuable in a large number of applications, up until today, fluorescent DNA base analogues remain virtually inapplicable for single-molecule fluorescence experiments which require extremely bright and photostable dyes. Insight into the photodegradation processes of these fluorophores is thus a key step in the continuous development towards dyes with improved performances. Here, we show that the commercially available fluorescent nucleobase analogue tC under intense long-term illumination and in the presence of O2 is degraded to form a single photoreaction product which we suggest to be the sulfoxide form of tC. The photoproduct is characterized by a blue-shifted absorption and a less intense fluorescence compared to that of tC. Interestingly, when tC is positioned inside double-stranded DNA this photodriven conversion of tC to its photoproduct greatly reduces the duplex stability of the overall double helix in which the probe is positioned. Since tC can be excited selectively at 400 nm, well outside the absorption band of the natural DNA bases, this observation points towards the application of tC as a general light-triggered switch of DNA duplex stability.

  17. Agminated blue nevus - Case report*

    PubMed Central

    Lisboa, Alice Paixão; Silvestre, Keline Jácome; Pedreira, Renata Leite; Alves, Natália Ribeiro de Magalhães; Obadia, Daniel Lago; Azulay-Abulafia, Luna

    2016-01-01

    Blue nevi are benign melanocytic lesions located in the deeper reticular dermis, consequence of failure of melanocytic migration into the dermal-epidermal junction from the neural crest. Lesions are usually asymptomatic and solitary, but may present in a multiple or agminated (grouped) pattern. The agminated subtype is formed when bluish-pigmented lesions cluster together in a well-defined area. Lesions can be flat or raised. We report the case of a patient who presented multiple bluish macules (1-3 mm in diameter) grouped on the left upper back. Dermoscopy and anatomic pathological examination were consistent with blue nevus. PMID:27828645

  18. Blue light emitting thiogallate phosphor

    DOEpatents

    Dye, Robert C.; Smith, David C.; King, Christopher N.; Tuenge, Richard T.

    1998-01-01

    A crystalline blue emitting thiogallate phosphor of the formula RGa.sub.2 S.sub.4 :Ce.sub.x where R is selected from the group consisting of calcium, strontium, barium and zinc, and x is from about 1 to 10 atomic percent, the phosphor characterized as having a crystalline microstructure on the size order of from about 100 .ANG. to about 10,000 .ANG. is provided together with a process of preparing a crystalline blue emitting thiogallate phosphor by depositing on a substrate by CVD and resultant thin film electroluminescent devices including a layer of such deposited phosphor on an ordinary glass substrate.

  19. Blue-green upconversion laser

    SciTech Connect

    Nguyen, Dinh C.; Faulkner, George E.

    1990-01-01

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

  20. The Blue-Collar Brain

    PubMed Central

    Van Orden, Guy; Hollis, Geoff; Wallot, Sebastian

    2012-01-01

    Much effort has gone into elucidating control of the body by the brain, less so the role of the body in controlling the brain. This essay develops the idea that the brain does a great deal of work in the service of behavior that is controlled by the body, a blue-collar role compared to the white-collar control exercised by the body. The argument that supports a blue-collar role for the brain is also consistent with recent discoveries clarifying the white-collar role of synergies across the body’s tensegrity structure, and the evidence of critical phenomena in brain and behavior. PMID:22719730

  1. Blue-green upconversion laser

    DOEpatents

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

    1990-08-14

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

  2. Dumb holes: analogues for black holes.

    PubMed

    Unruh, W G

    2008-08-28

    The use of sonic analogues to black and white holes, called dumb or deaf holes, to understand the particle production by black holes is reviewed. The results suggest that the black hole particle production is a low-frequency and low-wavenumber process.

  3. CO2 Capture with Enzyme Synthetic Analogue

    SciTech Connect

    Cordatos, Harry

    2010-03-01

    Project overview provides background on carbonic anhydrase transport mechanism for CO2 in the human body and proposed approach for ARPA-E project to create a synthetic enzyme analogue and utilize it in a membrane for CO2 capture from flue gas.

  4. Solanapyrone analogues from a Hawaiian fungicolous fungus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Four new solanayrone analogues (solanapyrones J-M; 1-4) have been isolated from an unidentified fungicolous fungus collected in Hawaii. The structures and relative configurations of these compounds were determined by analysis of ID NMR, 2D NMR, and MS data. Solanapyrone J(1) showed antifungal acti...

  5. [Dmt(1)]DALDA analogues modified with tyrosine analogues at position 1.

    PubMed

    Cai, Yunxin; Lu, Dandan; Chen, Zhen; Ding, Yi; Chung, Nga N; Li, Tingyou; Schiller, Peter W

    2016-08-01

    Analogues of [Dmt(1)]DALDA (H-Dmt-d-Arg-Phe-Lys-NH2; Dmt=2',6'-dimethyltyrosine), a potent μ opioid agonist peptide with mitochondria-targeted antioxidant activity were prepared by replacing Dmt with various 2',6'-dialkylated Tyr analogues, including 2',4',6'-trimethyltyrosine (Tmt), 2'-ethyl-6'-methyltyrosine (Emt), 2'-isopropyl-6'-methyltyrosine (Imt) and 2',6'-diethyltyrosine (Det). All compounds were selective μ opioid agonists and the Tmt(1)-, Emt(1) and Det(1)-analogues showed subnanomolar μ opioid receptor binding affinities. The Tmt(1)- and Emt(1)-analogues showed improved antioxidant activity compared to the Dmt(1)-parent peptide in the DPPH radical-scavenging capacity assay, and thus are of interest as drug candidates for neuropathic pain treatment.

  6. Tryptophan analogues. 1. Synthesis and antihypertensive activity of positional isomers.

    PubMed

    Safdy, M E; Kurchacova, E; Schut, R N; Vidrio, H; Hong, E

    1982-06-01

    A series of tryptophan analogues having the carboxyl function at the beta-position was synthesized and tested for antihypertensive activity. The 5-methoxy analogue 46 exhibited antihypertensive activity in the rat via the oral route and was much more potent than the normal tryptophan analogue. The methyl ester was found to be a critical structural feature for activity.

  7. Singing' the Black and Blues

    ERIC Educational Resources Information Center

    Fisher, Diane

    2004-01-01

    It is so obvious that the sky is blue in the daytime and black at night, but it took the smartest humans thousands of years of observation, thought, discussion, conjecture, and analysis to finally come up with answers that make scientific sense as to why the sky is these colors. This article discusses light and the scientific research…

  8. Teaching Sherman Alexie's "Reservation Blues."

    ERIC Educational Resources Information Center

    McFarland, Ronald E.

    2001-01-01

    A college teacher discusses his experiences of departing from the established literary canon to teach Sherman Alexie's "Reservation Blues" as part of an upper-level American literature survey class. Students reacted to the novel and its characters, evaluated Alexie's writing techniques, and discussed their personal experiences with Native…

  9. The Taos Blue Lake Ceremony.

    ERIC Educational Resources Information Center

    Bodine, John J.

    1988-01-01

    Describes the Blue Lake Ceremony of the Taos Pueblo Indians of New Mexico. Reproduces the 1906 account of the ceremony by anthropologist Matilda Coxe Stevenson and notes modern verification and change. Discusses the importance of this annual August pilgrimage and initiation rite to the preservation of Taos culture. (SV)

  10. Nobel Prize for blue LEDs

    NASA Astrophysics Data System (ADS)

    Kraftmakher, Yaakov

    2015-05-01

    A brief review of lighting technologies is presented. Unavoidable restrictions for incandescent light bulbs caused by the Planck distribution and properties of the human eye are illustrated. The efficiency and luminous efficacy of thermal radiation are calculated for various temperatures; the results clearly show the limitations for thermal radiators. The only way to overcome these limitations is using non-thermal radiators, such as fluorescent lamps and light-emitting diodes (LEDs). Unique advantages of LEDs undoubtedly made a revolution in this field. A crucial element of this progress is the blue LEDs (Nobel Prize 2014). Some experiments with a blue and a green LED are described: (i) the luminescence triggered in a green-yellow phosphor inside a white LED by the blue LED; (ii) radiant spectra and ‘efficiency droop’ in the LEDs; (iii) modulation of the blue LED up to 4 MHz; and (iv) the h/e ratio from the turn-on voltage of the green LED. The experiments are suitable for undergraduate laboratories and usable as classroom demonstrations.

  11. Practical utility of the blue spectral region

    NASA Technical Reports Server (NTRS)

    Ross, D. S.

    1972-01-01

    Some aspects of multispectral photography in the blue region are discussed briefly, and sample images are submitted to demonstrate the potential utility of the blue multispectral record for oceanography.

  12. 21 CFR 73.50 - Ultramarine blue.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... ultramarine blue is a blue pigment obtained by calcining a mixture of kaolin, sulfur, sodium carbonate, and... order to vary the shade. The pigment is a complex sodium aluminum sulfo-silicate having the...

  13. 21 CFR 73.50 - Ultramarine blue.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... ultramarine blue is a blue pigment obtained by calcining a mixture of kaolin, sulfur, sodium carbonate, and... order to vary the shade. The pigment is a complex sodium aluminum sulfo-silicate having the...

  14. 21 CFR 73.50 - Ultramarine blue.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... ultramarine blue is a blue pigment obtained by calcining a mixture of kaolin, sulfur, sodium carbonate, and... order to vary the shade. The pigment is a complex sodium aluminum sulfo-silicate having the...

  15. 21 CFR 73.50 - Ultramarine blue.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... ultramarine blue is a blue pigment obtained by calcining a mixture of kaolin, sulfur, sodium carbonate, and... order to vary the shade. The pigment is a complex sodium aluminum sulfo-silicate having the...

  16. 21 CFR 73.50 - Ultramarine blue.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... ultramarine blue is a blue pigment obtained by calcining a mixture of kaolin, sulfur, sodium carbonate, and... order to vary the shade. The pigment is a complex sodium aluminum sulfo-silicate having the...

  17. On Seeing Reddish Green and Yellowish Blue.

    ERIC Educational Resources Information Center

    Crane, Hewitt D.; Piantanida, Thomas P.

    1983-01-01

    Stabilization of the retinal image of the boundary between a pair of red/green or yellow/blue stripes, but not their outer edges, results in the entire region being perceived simultaneously as both red/green or yellow/blue. This suggests that the percepts of reddish-green/yellowish-blue apparently are possible in corticocortical color vision…

  18. Optimization of propafenone analogues as antimalarial leads.

    PubMed

    Lowes, David J; Guiguemde, W Armand; Connelly, Michele C; Zhu, Fangyi; Sigal, Martina S; Clark, Julie A; Lemoff, Andrew S; Derisi, Joseph L; Wilson, Emily B; Guy, R Kiplin

    2011-11-10

    Propafenone, a class Ic antiarrythmic drug, inhibits growth of cultured Plasmodium falciparum. While the drug's potency is significant, further development of propafenone as an antimalarial would require divorcing the antimalarial and cardiac activities as well as improving the pharmacokinetic profile of the drug. A small array of propafenone analogues was designed and synthesized to address the cardiac ion channel and PK liabilities. Testing of this array revealed potent inhibitors of the 3D7 (drug sensitive) and K1 (drug resistant) strains of P. falciparum that possessed significantly reduced ion channel effects and improved metabolic stability. Propafenone analogues are unusual among antimalarial leads in that they are more potent against the multidrug resistant K1 strain of P. falciparum compared to the 3D7 strain.

  19. Enzymatic synthesis of lipid II and analogues.

    PubMed

    Huang, Lin-Ya; Huang, Shih-Hsien; Chang, Ya-Chih; Cheng, Wei-Chieh; Cheng, Ting-Jen R; Wong, Chi-Huey

    2014-07-28

    The emergence of antibiotic resistance has prompted active research in the development of antibiotics with new modes of action. Among all essential bacterial proteins, transglycosylase polymerizes lipid II into peptidoglycan and is one of the most favorable targets because of its vital role in peptidoglycan synthesis. Described in this study is a practical enzymatic method for the synthesis of lipid II, coupled with cofactor regeneration, to give the product in a 50-70% yield. This development depends on two key steps: the overexpression of MraY for the synthesis of lipid I and the use of undecaprenol kinase for the preparation of polyprenol phosphates. This method was further applied to the synthesis of lipid II analogues. It was found that MraY and undecaprenol kinase can accept a wide range of lipids containing various lengths and configurations. The activity of lipid II analogues for bacterial transglycolase was also evaluated.

  20. Polyamine analogues targeting epigenetic gene regulation.

    PubMed

    Huang, Yi; Marton, Laurence J; Woster, Patrick M; Casero, Robert A

    2009-11-04

    Over the past three decades the metabolism and functions of the polyamines have been actively pursued as targets for antineoplastic therapy. Interactions between cationic polyamines and negatively charged nucleic acids play a pivotal role in DNA stabilization and RNA processing that may affect gene expression, translation and protein activity. Our growing understanding of the unique roles that the polyamines play in chromatin regulation, and the discovery of novel proteins homologous with specific regulatory enzymes in polyamine metabolism, have led to our interest in exploring chromatin remodelling enzymes as potential therapeutic targets for specific polyamine analogues. One of our initial efforts focused on utilizing the strong affinity that the polyamines have for chromatin to create a backbone structure, which could be combined with active-site-directed inhibitor moieties of HDACs (histone deacetylases). Specific PAHAs (polyaminohydroxamic acids) and PABAs (polyaminobenzamides) polyamine analogues have demonstrated potent inhibition of the HDACs, re-expression of p21 and significant inhibition of tumour growth. A second means of targeting the chromatin-remodelling enzymes with polyamine analogues was facilitated by the recent identification of flavin-dependent LSD1 (lysine-specific demethylase 1). The existence of this enzyme demonstrated that histone lysine methylation is a dynamic process similar to other histone post-translational modifications. LSD1 specifically catalyses demethylation of mono- and di-methyl Lys4 of histone 3, key positive chromatin marks associated with transcriptional activation. Structural and catalytic similarities between LSD1 and polyamine oxidases facilitated the identification of biguanide, bisguanidine and oligoamine polyamine analogues that are potent inhibitors of LSD1. Cellular inhibition of LSD1 by these unique compounds led to the re-activation of multiple epigenetically silenced genes important in tumorigenesis. The use of

  1. Benchmarking analogue models of brittle thrust wedges

    NASA Astrophysics Data System (ADS)

    Schreurs, Guido; Buiter, Susanne J. H.; Boutelier, Jennifer; Burberry, Caroline; Callot, Jean-Paul; Cavozzi, Cristian; Cerca, Mariano; Chen, Jian-Hong; Cristallini, Ernesto; Cruden, Alexander R.; Cruz, Leonardo; Daniel, Jean-Marc; Da Poian, Gabriela; Garcia, Victor H.; Gomes, Caroline J. S.; Grall, Céline; Guillot, Yannick; Guzmán, Cecilia; Hidayah, Triyani Nur; Hilley, George; Klinkmüller, Matthias; Koyi, Hemin A.; Lu, Chia-Yu; Maillot, Bertrand; Meriaux, Catherine; Nilfouroushan, Faramarz; Pan, Chang-Chih; Pillot, Daniel; Portillo, Rodrigo; Rosenau, Matthias; Schellart, Wouter P.; Schlische, Roy W.; Take, Andy; Vendeville, Bruno; Vergnaud, Marine; Vettori, Matteo; Wang, Shih-Hsien; Withjack, Martha O.; Yagupsky, Daniel; Yamada, Yasuhiro

    2016-11-01

    We performed a quantitative comparison of brittle thrust wedge experiments to evaluate the variability among analogue models and to appraise the reproducibility and limits of model interpretation. Fifteen analogue modeling laboratories participated in this benchmark initiative. Each laboratory received a shipment of the same type of quartz and corundum sand and all laboratories adhered to a stringent model building protocol and used the same type of foil to cover base and sidewalls of the sandbox. Sieve structure, sifting height, filling rate, and details on off-scraping of excess sand followed prescribed procedures. Our analogue benchmark shows that even for simple plane-strain experiments with prescribed stringent model construction techniques, quantitative model results show variability, most notably for surface slope, thrust spacing and number of forward and backthrusts. One of the sources of the variability in model results is related to slight variations in how sand is deposited in the sandbox. Small changes in sifting height, sifting rate, and scraping will result in slightly heterogeneous material bulk densities, which will affect the mechanical properties of the sand, and will result in lateral and vertical differences in peak and boundary friction angles, as well as cohesion values once the model is constructed. Initial variations in basal friction are inferred to play the most important role in causing model variability. Our comparison shows that the human factor plays a decisive role, and even when one modeler repeats the same experiment, quantitative model results still show variability. Our observations highlight the limits of up-scaling quantitative analogue model results to nature or for making comparisons with numerical models. The frictional behavior of sand is highly sensitive to small variations in material state or experimental set-up, and hence, it will remain difficult to scale quantitative results such as number of thrusts, thrust spacing

  2. Antitumoral cyclic peptide analogues of chlamydocin.

    PubMed

    Bernardi, E; Fauchere, J L; Atassi, G; Viallefont, P; Lazaro, R

    1993-01-01

    A series of cyclic tetrapeptides bearing the bioactive alkylating group on an epsilon-amino-lysyl function have been examined for their antitumoral activity on L1210 and P388 murine leukemia cell lines. One analogue belonging to the chlamydocin family and bearing a beta-chloroethylnitrosourea group was found to be potent at inhibiting L1210 cell proliferation and had a higher therapeutic index than the reference compound bis-beta-chloroethylnitrosourea (BCNU) on the in vivo P388-induced leukemia model.

  3. Synthesis of constrained analogues of tryptophan

    PubMed Central

    Negrato, Marco; Abbiati, Giorgio; Dell’Acqua, Monica

    2015-01-01

    Summary A Lewis acid-catalysed diastereoselective [4 + 2] cycloaddition of vinylindoles and methyl 2-acetamidoacrylate, leading to methyl 3-acetamido-1,2,3,4-tetrahydrocarbazole-3-carboxylate derivatives, is described. Treatment of the obtained cycloadducts under hydrolytic conditions results in the preparation of a small library of compounds bearing the free amino acid function at C-3 and pertaining to the class of constrained tryptophan analogues. PMID:26664620

  4. The Brookhaven electron analogue, 1953--1957

    SciTech Connect

    Plotkin, M.

    1991-12-18

    The following topics are discussed on the Brookhaven electron analogue: L.J. Haworth and E.L. VanHorn letters; Original G.K. Green outline for report; General description; Parameter list; Mechanical Assembly; Alignment; Degaussing; Vacuum System; Injection System; The pulsed inflector; RF System; Ferrite Cavity; Pick-up electrodes and preamplifiers; Radio Frequency power amplifier; Lens supply; Controls and Power; and RF acceleration summary.

  5. Thymidine analogues for tracking DNA synthesis.

    PubMed

    Cavanagh, Brenton L; Walker, Tom; Norazit, Anwar; Meedeniya, Adrian C B

    2011-09-15

    Replicating cells undergo DNA synthesis in the highly regulated, S-phase of the cell cycle. Analogues of the pyrimidine deoxynucleoside thymidine may be inserted into replicating DNA, effectively tagging dividing cells allowing their characterisation. Tritiated thymidine, targeted using autoradiography was technically demanding and superseded by 5-bromo-2-deoxyuridine (BrdU) and related halogenated analogues, detected using antibodies. Their detection required the denaturation of DNA, often constraining the outcome of investigations. Despite these limitations BrdU alone has been used to target newly synthesised DNA in over 20,000 reviewed biomedical studies. A recent breakthrough in "tagging DNA synthesis" is the thymidine analogue 5-ethynyl-2'-deoxyuridine (EdU). The alkyne group in EdU is readily detected using a fluorescent azide probe and copper catalysis using 'Huisgen's reaction' (1,3-dipolar cycloaddition or 'click chemistry'). This rapid, two-step biolabelling approach allows the tagging and imaging of DNA within cells whilst preserving the structural and molecular integrity of the cells. The bio-orthogonal detection of EdU allows its application in more experimental assays than previously possible with other "unnatural bases". These include physiological, anatomical and molecular biological experimentation in multiple fields including, stem cell research, cancer biology, and parasitology. The full potential of EdU and related molecules in biomedical research remains to be explored.

  6. Blood Loss Estimation Using Gauze Visual Analogue

    PubMed Central

    Ali Algadiem, Emran; Aleisa, Abdulmohsen Ali; Alsubaie, Huda Ibrahim; Buhlaiqah, Noora Radhi; Algadeeb, Jihad Bagir; Alsneini, Hussain Ali

    2016-01-01

    Background Estimating intraoperative blood loss can be a difficult task, especially when blood is mostly absorbed by gauze. In this study, we have provided an improved method for estimating blood absorbed by gauze. Objectives To develop a guide to estimate blood absorbed by surgical gauze. Materials and Methods A clinical experiment was conducted using aspirated blood and common surgical gauze to create a realistic amount of absorbed blood in the gauze. Different percentages of staining were photographed to create an analogue for the amount of blood absorbed by the gauze. Results A visual analogue scale was created to aid the estimation of blood absorbed by the gauze. The absorptive capacity of different gauze sizes was determined when the gauze was dripping with blood. The amount of reduction in absorption was also determined when the gauze was wetted with normal saline before use. Conclusions The use of a visual analogue may increase the accuracy of blood loss estimation and decrease the consequences related to over or underestimation of blood loss. PMID:27626017

  7. The Physics of the Blues

    NASA Astrophysics Data System (ADS)

    Gibson, J. Murray

    2009-03-01

    In looking at the commonalities between music and science, one sees that the musician's palette is based on the principles of physics. The pitch of a musical note is determined by the frequency of the sound wave. The scales that musicians use to create and play music can be viewed as a set of rules. What makes music interesting is how musicians develop those rules and create ambiguity with them. I will discuss the evolution of western musical scales in this context. As a particular example, ``Blue'' notes are very harmonic notes that are missing from the equal temperament scale. The techniques of piano blues and jazz represent the melding of African and Western music into something totally new and exciting. Live keyboard demonstrations will be used. Beyond any redeeming entertainment value the talk will emphasize the serious connections between science and art in music. Nevertheless tips will be accepted.

  8. Blue phases of cholesteryl nonanoate

    NASA Astrophysics Data System (ADS)

    Meiboom, S.; Sammon, M.

    1981-07-01

    The transformation on heating of an ordinary (helical) cholesteric liquid crystal (CHOL) into the isotropic phase (ISO) often occurs via a number of intermediate "blue" phases. We find the following scheme of phase transitions in cholesteryl nonanoate: CHOL-->91.35BPI-->91.76BPII-->91.84BPIII-->91.95ISO. Here BPI, BPII, and BPIII indicate three distinct, thermodynamically stable phases; transition temperatures are in °C. From observations of supercooling and coexistence, we conclude that all these transformations are first order, except possibly the BPIII-->ISO, the character of which remains in doubt. A similar behavior is found in cholesteryl myristate and in a mixture of cholesteryl nonanoate and cholesteryl chloride. A few observations having a bearing on the structure of the blue phases are reported.

  9. Status of Blue Ridge Reservoir

    SciTech Connect

    Not Available

    1990-09-01

    This is one in a series of reports prepared by the Tennessee Valley Authority (TVA) for those interested in the conditions of TVA reservoirs. This overview of Blue Ridge Reservoir summarizes reservoir and watershed characteristics, reservoir uses and use impairments, water quality and aquatic biological conditions, and activities of reservoir management agencies. This information was extracted from the most current reports and data available, as well as interview with water resource professionals in various federal, state, and local agencies. Blue Ridge Reservoir is a single-purpose hydropower generating project. When consistent with this primary objective, the reservoir is also operated to benefit secondary objectives including water quality, recreation, fish and aquatic habitat, development of shoreline, aesthetic quality, and other public and private uses that support overall regional economic growth and development. 8 refs., 1 fig.

  10. Ol' Blue Eyes, in Focus

    ERIC Educational Resources Information Center

    Nelson, Michael

    2009-01-01

    Scholarly books with "identity" and "culture" in the title have loomed large on academic publishing lists for several years. Scholarly books with "Sinatra" in the title are a more recent phenomenon. Despite his six-decade career as the Voice (the 1940s), the Chairman of the Board (the 50s and 60s), and Ol' Blue Eyes (the 70s through his death, in…

  11. Models of Individual Blue Stragglers

    NASA Astrophysics Data System (ADS)

    Sills, Alison

    This chapter describes the current state of models of individual blue stragglers. Stellar collisions, binary mergers (or coalescence), and partial or ongoing mass transfer have all been studied in some detail. The products of stellar collisions retain memory of their parent stars and are not fully mixed. Very high initial rotation rates must be reduced by an unknown process to allow the stars to collapse to the main sequence. The more massive collision products have shorter lifetimes than normal stars of the same mass, while products between low mass stars are long-lived and look very much like normal stars of their mass. Mass transfer can result in a merger, or can produce another binary system with a blue straggler and the remnant of the original primary. The products of binary mass transfer cover a larger portion of the colour-magnitude diagram than collision products for two reasons: there are more possible configurations which produce blue stragglers, and there are differing contributions to the blended light of the system. The effects of rotation may be substantial in both collision and merger products, and could result in significant mixing unless angular momentum is lost shortly after the formation event. Surface abundances may provide ways to distinguish between the formation mechanisms, but care must be taken to model the various mixing mechanisms properly before drawing strong conclusions. Avenues for future work are outlined.

  12. The Cryptochrome Blue Light Receptors

    PubMed Central

    Yu, Xuhong; Liu, Hongtao; Klejnot, John; Lin, Chentao

    2010-01-01

    Cryptochromes are photolyase-like blue light receptors originally discovered in Arabidopsis but later found in other plants, microbes, and animals. Arabidopsis has two cryptochromes, CRY1 and CRY2, which mediate primarily blue light inhibition of hypocotyl elongation and photoperiodic control of floral initiation, respectively. In addition, cryptochromes also regulate over a dozen other light responses, including circadian rhythms, tropic growth, stomata opening, guard cell development, root development, bacterial and viral pathogen responses, abiotic stress responses, cell cycles, programmed cell death, apical dominance, fruit and ovule development, seed dormancy, and magnetoreception. Cryptochromes have two domains, the N-terminal PHR (Photolyase-Homologous Region) domain that bind the chromophore FAD (flavin adenine dinucleotide), and the CCE (CRY C-terminal Extension) domain that appears intrinsically unstructured but critical to the function and regulation of cryptochromes. Most cryptochromes accumulate in the nucleus, and they undergo blue light-dependent phosphorylation or ubiquitination. It is hypothesized that photons excite electrons of the flavin molecule, resulting in redox reaction or circular electron shuttle and conformational changes of the photoreceptors. The photoexcited cryptochrome are phosphorylated to adopt an open conformation, which interacts with signaling partner proteins to alter gene expression at both transcriptional and posttranslational levels and consequently the metabolic and developmental programs of plants. PMID:21841916

  13. The Cryptochrome Blue Light Receptors.

    PubMed

    Yu, Xuhong; Liu, Hongtao; Klejnot, John; Lin, Chentao

    2010-09-23

    Cryptochromes are photolyase-like blue light receptors originally discovered in Arabidopsis but later found in other plants, microbes, and animals. Arabidopsis has two cryptochromes, CRY1 and CRY2, which mediate primarily blue light inhibition of hypocotyl elongation and photoperiodic control of floral initiation, respectively. In addition, cryptochromes also regulate over a dozen other light responses, including circadian rhythms, tropic growth, stomata opening, guard cell development, root development, bacterial and viral pathogen responses, abiotic stress responses, cell cycles, programmed cell death, apical dominance, fruit and ovule development, seed dormancy, and magnetoreception. Cryptochromes have two domains, the N-terminal PHR (Photolyase-Homologous Region) domain that bind the chromophore FAD (flavin adenine dinucleotide), and the CCE (CRY C-terminal Extension) domain that appears intrinsically unstructured but critical to the function and regulation of cryptochromes. Most cryptochromes accumulate in the nucleus, and they undergo blue light-dependent phosphorylation or ubiquitination. It is hypothesized that photons excite electrons of the flavin molecule, resulting in redox reaction or circular electron shuttle and conformational changes of the photoreceptors. The photoexcited cryptochrome are phosphorylated to adopt an open conformation, which interacts with signaling partner proteins to alter gene expression at both transcriptional and posttranslational levels and consequently the metabolic and developmental programs of plants.

  14. Blue straggler stars: lessons from open clusters.

    NASA Astrophysics Data System (ADS)

    Geller, Aaron M.

    Open clusters enable a deep dive into blue straggler characteristics. Recent work shows that the binary properties (frequency, orbital elements and companion masses and evolutionary states) of the blue stragglers are the most important diagnostic for determining their origins. To date the multi-epoch radial-velocity observations necessary for characterizing these blue straggler binaries have only been carried out in open clusters. In this paper, I highlight recent results in the open clusters NGC 188, NGC 2682 (M67) and NGC 6819. The characteristics of many of the blue stragglers in these open clusters point directly to origins through mass transfer from an evolved donor star. Additionally, a handful of blue stragglers show clear signatures of past dynamical encounters. These comprehensive, diverse and detailed observations also reveal important challenges for blue straggler formation models (and particularly the mass-transfer channel), which we must overcome to fully understand the origins of blue straggler stars and other mass-transfer products.

  15. Localized Eruptive Blue Nevi after Herpes Zoster

    PubMed Central

    Colson, Fany; Arrese, Jorge E.; Nikkels, Arjen F.

    2016-01-01

    A 52-year-old White man presented with a dozen small, well-restricted, punctiform, asymptomatic, blue-gray macules on the left shoulder. A few months earlier, he had been treated with oral acyclovir for herpes zoster (HZ) affecting the left C7–C8 dermatomes. All the blue macules appeared over a short period of time and then remained stable. The patient had not experienced any previous trauma or had tattooing in this anatomical region. The clinical diagnosis suggested blue nevi. Dermatoscopy revealed small, well-limited, dark-blue, compact, homogeneous areas evoking dermal blue nevi. An excisional biopsy was performed and the histological examination confirmed a blue nevus. As far as we are aware of, this is the first report of eruptive blue nevi following HZ, and it should be included in the differential diagnosis of zosteriform dermatoses responding to an isotopic pathway. In addition, a brief review concerning eruptive nevi is presented. PMID:27462219

  16. Polish Terms for "Blue" in the Perspective of Vantage Theory

    ERIC Educational Resources Information Center

    Stanulewicz, Danuta

    2010-01-01

    The Polish set of terms for blue includes, inter alia, the following adjectives: "niebieski" "blue", "blekitny" "(sky) blue", "granatowy" "navy blue", "lazurowy" "azure", "modry" "(intense) blue" and "siny" "(grey) violet-blue". The adjective "niebieski" is the basic term; however, it shares some of its functions with "blekitny", which is…

  17. Adsorption of Methylene Blue, Bromophenol Blue, and Coomassie Brilliant Blue by α-chitin nanoparticles

    PubMed Central

    Dhananasekaran, Solairaj; Palanivel, Rameshthangam; Pappu, Srinivasan

    2015-01-01

    Expelling of dyestuff into water resource system causes major thread to the environment. Adsorption is the cost effective and potential method to remove the dyes from the effluents. Therefore, an attempt was made to study the adsorption of dyestuff (Methylene Blue (MB), Bromophenol Blue (BPB) and Coomassie Brilliant Blue (CBB)) by α-chitin nanoparticles (CNP) prepared from Penaeus monodon (Fabricius, 1798) shell waste. On contrary to the most recognizable adsorption studies using chitin, this is the first study using unique nanoparticles of ⩽50 nm used for the dye adsorption process. The results showed that the adsorption process increased with increase in the concentration of CNP, contact time and temperature with the dyestuff, whereas the adsorption process decreased with increase in the initial dye concentration and strong acidic pH. The results from Fourier transform infrared (FTIR) spectroscopy confirmed that the interaction between dyestuff and CNP involved physical adsorption. The adsorption process obeys Langmuir isotherm (R2 values were 0.992, 0.999 and 0.992 for MB, BPB and CBB, and RL value lies between 0 and 1 for all the three dyes) and pseudo second order kinetics (R2 values were 0.996, 0.999 and 0.996 for MB, BPB and CBB) more effectively. The isotherm and kinetic models confirmed that CNP can be used as a suitable adsorbent material for the removal of dyestuff from effluents. PMID:26843977

  18. Adsorption of Methylene Blue, Bromophenol Blue, and Coomassie Brilliant Blue by α-chitin nanoparticles.

    PubMed

    Dhananasekaran, Solairaj; Palanivel, Rameshthangam; Pappu, Srinivasan

    2016-01-01

    Expelling of dyestuff into water resource system causes major thread to the environment. Adsorption is the cost effective and potential method to remove the dyes from the effluents. Therefore, an attempt was made to study the adsorption of dyestuff (Methylene Blue (MB), Bromophenol Blue (BPB) and Coomassie Brilliant Blue (CBB)) by α-chitin nanoparticles (CNP) prepared from Penaeus monodon (Fabricius, 1798) shell waste. On contrary to the most recognizable adsorption studies using chitin, this is the first study using unique nanoparticles of ⩽50 nm used for the dye adsorption process. The results showed that the adsorption process increased with increase in the concentration of CNP, contact time and temperature with the dyestuff, whereas the adsorption process decreased with increase in the initial dye concentration and strong acidic pH. The results from Fourier transform infrared (FTIR) spectroscopy confirmed that the interaction between dyestuff and CNP involved physical adsorption. The adsorption process obeys Langmuir isotherm (R (2) values were 0.992, 0.999 and 0.992 for MB, BPB and CBB, and RL value lies between 0 and 1 for all the three dyes) and pseudo second order kinetics (R (2) values were 0.996, 0.999 and 0.996 for MB, BPB and CBB) more effectively. The isotherm and kinetic models confirmed that CNP can be used as a suitable adsorbent material for the removal of dyestuff from effluents.

  19. Fire Whirls, Vortex Breakdown(?), and Blue Whirls

    NASA Astrophysics Data System (ADS)

    Oran, Elaine; Xiao, Huahua; Gollner, Michael

    2016-11-01

    As we were investigating the efficiency of fire-whirl burning on water, we observed the usual transformation of a pool fire to a fire whirl, and then suddenly, we saw the fire undergo a third transition. A blue cup appeared around the base of the fire whirl, surrounding the yellow flame, the yellow flame receded into the cup and finally disappeared. What remained was a small, rapidly spinning blue flame that burned until the fuel on the water was consumed. The blue whirl was shaped like a spinning cup, closed at the bottom near the water surface, and spreading in radius moving upwards towards the rim. Above the blue cup lip, there was a purple cone-shaped mist. The fuel was usually n-heptane, but at one point it was crude oil, and still the blue whirl formed naturally. The height of the fire whirl on the laboratory pan was larger than a half meter, and this evolved into a blue whirl about 4-8 cm high. Occasionally the blue whirl would become "unstable" and revert to a transitional state of blue cup holding a yellow flame. When the blue whirl formed, turbulence seemed to disappear, and the flame became quiet. We will show videos of how this happened and discuss the evolution of the fire whirl to the blue whirl in vortex-breakdown concepts. This work was supported by and EAGER award from NSF and Minta Martin Endowment Funds in the Department of Aerospace Engineering at the University of Maryland.

  20. BLUE STRAGGLERS IN GLOBULAR CLUSTER 47 TUCANAE

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The core of globular cluster 47 Tucanae is home to many blue stragglers, rejuvenated stars that glow with the blue light of young stars. A ground-based telescope image (on the left) shows the entire crowded core of 47 Tucanae, located 15,000 light-years away in the constellation Tucana. Peering into the heart of the globular cluster's bright core, the Hubble Space Telescope's Wide Field and Planetary Camera 2 separated the dense clump of stars into many individual stars (image on right). Some of these stars shine with the light of old stars; others with the blue light of blue stragglers. The yellow circles in the Hubble telescope image highlight several of the cluster's blue stragglers. Analysis for this observation centered on one massive blue straggler. Astronomers theorize that blue stragglers are formed either by the slow merger of stars in a double-star system or by the collision of two unrelated stars. For the blue straggler in 47 Tucanae, astronomers favor the slow merger scenario. This image is a 3-color composite of archival Hubble Wide Field and Planetary Camera 2 images in the ultraviolet (blue), blue (green), and violet (red) filters. Color tables were assigned and scaled so that the red giant stars appear orange, main-sequence stars are white/green, and blue stragglers are appropriately blue. The ultraviolet images were taken on Oct. 25, 1995, and the blue and violet images were taken on Sept. 1, 1995. Credit: Rex Saffer (Villanova University) and Dave Zurek (STScI), and NASA

  1. Polyamine analogues bind human serum albumin.

    PubMed

    Beauchemin, R; N'soukpoé-Kossi, C N; Thomas, T J; Thomas, T; Carpentier, R; Tajmir-Riahi, H A

    2007-10-01

    Polyamine analogues show antitumor activity in experimental models, and their ability to alter activity of cytotoxic chemotherapeutic agents in breast cancer is well documented. Association of polyamines with nucleic acids and protein is included in their mechanism of action. The aim of this study was to examine the interaction of human serum albumin (HSA) with several polyamine analogues, such as 1,11-diamino-4,8-diazaundecane (333), 3,7,11,15-tetrazaheptadecane.4HCl (BE-333), and 3,7,11,15,19-pentazahenicosane.5HCl (BE-3333), in aqueous solution at physiological conditions using a constant protein concentration and various polyamine contents (microM to mM). FTIR, UV-visible, and CD spectroscopic methods were used to determine the polyamine binding mode and the effects of polyamine complexation on protein stability and secondary structure. Structural analysis showed that polyamines bind nonspecifically (H-bonding) via polypeptide polar groups with binding constants of K333 = 9.30 x 10(3) M(-1), KBE-333 = 5.63 x 10(2) M(-1), and KBE-3333 = 3.66 x 10(2) M(-1). The protein secondary structure showed major alterations with a reduction of alpha-helix from 55% (free protein) to 43-50% and an increase of beta-sheet from 17% (free protein) to 29-36% in the 333, BE-333, and BE-3333 complexes, indicating partial protein unfolding upon polyamine interaction. HSA structure was less perturbed by polyamine analogues compared to those of the biogenic polyamines.

  2. New synthetic approaches towards analogues of bedaquiline.

    PubMed

    Priebbenow, Daniel L; Barbaro, Lisa; Baell, Jonathan B

    2016-10-12

    Multi-drug resistant tuberculosis (MDR-TB) is of growing global concern and threatens to undermine increasing efforts to control the worldwide spread of tuberculosis (TB). Bedaquiline has recently emerged as a new drug developed to specifically treat MDR-TB. Despite being highly effective as a result of its unique mode of action, bedaquiline has been associated with significant toxicities and as such, safety concerns are limiting its clinical use. In order to access pharmaceutical agents that exhibit an improved safety profile for the treatment of MDR-TB, new synthetic pathways to facilitate the preparation of bedaquiline and analogues thereof have been discovered.

  3. The Lehmer Matrix and Its Recursive Analogue

    DTIC Science & Technology

    2010-01-01

    for failing to comply with a collection of information if it does not display a currently valid OMB control number . 1. REPORT DATE 2010 2. REPORT...TYPE 3. DATES COVERED 00-00-2010 to 00-00-2010 4. TITLE AND SUBTITLE The Lehmer matrix and its recursive analogue 5a. CONTRACT NUMBER 5b...GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND

  4. Blue and UV Semiconductor Lasers

    NASA Astrophysics Data System (ADS)

    Krukowski, S.; Skierbiszewski, C.; Perlin, P.; Leszczynski, M.; Bockowski, M.; Porowski, S.

    2006-04-01

    Despite many technological difficulties the group III nitrides: GaN, AlN and InN and their alloys are primary candidates for electro-optical coherent light sources. In the recent years the research and technology of the nitride based continuous wave (CW) laser diodes (LDs) led to creation of blue-violet coherent light sources of power up to 200 mW. The progress has been attained by using various ways to attack the main obstacles in the technology of these devices such as insufficient size of high quality lattice matched substrates, low p-doping efficiency of Mg acceptor, poor contact to p-type semiconductor and low efficiency of radiative recombination. The two different approaches were used to overcome the substrate problem: hetero-epitaxy and homoepitaxy. Homoepitaxy used high pressure GaN high quality crystals. Heteroepitaxy used sapphire, SiC or GaAs substrates and very sophisticated techniques of reduction of the dislocation density. The low p-doping efficiency by using Mg acceptor is related to creation of Mg--H complexes due to hydrogen presence during the growth of laser diode quantum structures. In addition, Mg acceptor has low efficiency due to its high energy. High Mg concentrations can be obtained by using either MOCVD or ammonia source MBE growth. An alternative route is to use hydrogen-free plasma activated MBE (PA-MBE) method. The recent advances and the prospects of both approaches will be discussed. Solid AlGaInN solution offers a possibility to cover wide spectral range, starting from near UV to blue, green and red. Arsenide based laser diodes (LDs) are efficient coherent red light sources. Therefore, nitride based LDs are considered to be devices of choice for green, blue and UV spectral range. So far only blue and violet laser has been realized. The progress toward green and UV lasers is far less spectacular. The results in all these areas and future prospects will be discussed.

  5. U.S. Nuclear Regulatory Commission natural analogue research program

    SciTech Connect

    Kovach, L.A.; Ott, W.R.

    1995-09-01

    This article describes the natural analogue research program of the U.S. Nuclear Regulatory Commission (US NRC). It contains information on the regulatory context and organizational structure of the high-level radioactive waste research program plan. It also includes information on the conditions and processes constraining selection of natural analogues, describes initiatives of the US NRC, and describes the role of analogues in the licensing process.

  6. CO2 Removal using a Synthetic Analogue of Carbonic Anhydrase

    SciTech Connect

    Cordatos, Harry

    2010-09-14

    Project attempts to develop a synthetic analogue for carbonic anhydrase and incorporate it in a membrane for separation of CO2 from coal power plant flue gas. Conference poster presents result of first 9 months of project progress including concept, basic system architecture and membrane properties target, results of molecular modeling for analogue - CO2 interaction, and next steps of testing analogue resistance to flue gas contaminants.

  7. Synthesis of a cyanopeptide-analogue with trypsin activating properties.

    PubMed

    Radau, G; Rauh, D

    2000-04-17

    An efficient synthesis of a peptidic analogue of cyanobacterial metabolites with proposed serine protease inhibitory activity has been developed. Surprisingly, one trypsin activating compound was obtained.

  8. Geothermal Technologies Program Blue Ribbon Panel Recommendations

    SciTech Connect

    none,

    2011-06-17

    The Geothermal Technologies Program assembled a geothermal Blue Ribbon Panel on March 22-23, 2011 in Albuquerque, New Mexico for a guided discussion on the future of geothermal energy in the United States and the role of the DOE Program. The Geothermal Blue Ribbon Panel Report captures the discussions and recommendations of the experts. An addendum is available here: http://www.eere.energy.gov/geothermal/pdfs/gtp_blue_ribbon_panel_report_addendum10-2011.pdf

  9. Long-term predictions using natural analogues

    SciTech Connect

    Ewing, R.C.

    1995-09-01

    One of the unique and scientifically most challenging aspects of nuclear waste isolation is the extrapolation of short-term laboratory data (hours to years) to the long time periods (10{sup 3}-10{sup 5} years) required by regulatory agencies for performance assessment. The direct validation of these extrapolations is not possible, but methods must be developed to demonstrate compliance with government regulations and to satisfy the lay public that there is a demonstrable and reasonable basis for accepting the long-term extrapolations. Natural systems (e.g., {open_quotes}natural analogues{close_quotes}) provide perhaps the only means of partial {open_quotes}validation,{close_quotes} as well as data that may be used directly in the models that are used in the extrapolation. Natural systems provide data on very large spatial (nm to km) and temporal (10{sup 3}-10{sup 8} years) scales and in highly complex terranes in which unknown synergisms may affect radionuclide migration. This paper reviews the application (and most importantly, the limitations) of data from natural analogue systems to the {open_quotes}validation{close_quotes} of performance assessments.

  10. Self-Powered Analogue Smart Skin.

    PubMed

    Shi, Mayue; Zhang, Jinxin; Chen, Haotian; Han, Mengdi; Shankaregowda, Smitha A; Su, Zongming; Meng, Bo; Cheng, Xiaoliang; Zhang, Haixia

    2016-04-26

    The progress of smart skin technology presents unprecedented opportunities for artificial intelligence. Resolution enhancement and energy conservation are critical to improve the perception and standby time of robots. Here, we present a self-powered analogue smart skin for detecting contact location and velocity of the object, based on a single-electrode contact electrification effect and planar electrostatic induction. Using an analogue localizing method, the resolution of this two-dimensional smart skin can be achieved at 1.9 mm with only four terminals, which notably decreases the terminal number of smart skins. The sensitivity of this smart skin is remarkable, which can even perceive the perturbation of a honey bee. Meanwhile, benefiting from the triboelectric mechanism, extra power supply is unnecessary for this smart skin. Therefore, it solves the problems of batteries and connecting wires for smart skins. With microstructured poly(dimethylsiloxane) films and silver nanowire electrodes, it can be covered on the skin with transparency, flexibility, and high sensitivity.

  11. Morphological responses of wheat to blue light

    NASA Technical Reports Server (NTRS)

    Barnes, C.; Bugbee, B.

    1992-01-01

    Blue light significantly increased tillering in wheat (Triticum aestivum L.) plants grown at the same photosynthetic photon flux (PPF). Plants were grown under two levels of blue light (400-500 nm) in a controlled environment with continuous irradiation. Plants received either 50 micromoles m-2 s-1 of blue light or 2 micromoles m-2 s-1 blue light from filtered metal halide lamps at a total irradiance of 200 micromoles m-2 s-1 PPF (400-700 nm). Plants tillered an average of 25% more under the higher level of blue light. Blue light also caused a small, but consistent, increase in main culm development, measured as Haun stage. Leaf length was reduced by higher levels of blue light, while plant dry-mass was not significantly affected by blue light. Applying the principle of equivalent light action, the results suggest that tillering and leaf elongation are mediated by the blue-UV light receptor(s) because phytochrome photoequilibrium for each treatment were nearly identical.

  12. Optically tuneable blue phase photonic band gaps

    SciTech Connect

    Liu, H.-Y.; Wang, C.-T.; Hsu, C.-Y.; Lin, T.-H.; Liu, J.-H.

    2010-03-22

    This study investigates an optically switchable band gap of photonic crystal that is based on an azobenzene-doped liquid crystal blue phase. The trans-cis photoisomerization of azobenzene deforms the cubic unit cell of the blue phase and shifts the photonic band gap. The fast back-isomerization of azobenzene was induced by irradiation with different wavelengths light. The crystal structure is verified using Kossel diffraction diagram. An optically addressable blue phase display, based on Bragg reflection from the photonic band gap, is also demonstrated. The tunable ranges are around red, green, and blue wavelengths and exhibit a bright saturated color.

  13. Evaluation of blue and green absorbing proteorhodopsins as holographic materials.

    PubMed

    Xi, Bangwei; Tetley, William C; Marcy, Duane L; Zhong, Cheng; Whited, Gregg; Birge, Robert R; Stuart, Jeffrey A

    2008-02-28

    Transient holographic diffraction is observed for the green (GPR) and blue (BPR) absorbing proteorhodopsins (BAC31A8 and HOT75M1, respectively), as well as the GPR E108Q and BPR E110Q variants. In contrast to bacteriorhodopsin, where the metastable bR-M pair is responsible for generating diffraction, the pR and red-shifted N-like states fulfill that role in both the green and blue wild-type proteorhodopsins. The GPR E108Q and BPR E110Q variants, however, behave more similarly to their bacteriorhodopsin analogue, D96N, with diffraction arising from the PR M-state (strongly enhanced in both GPR E108Q and BPR E110Q). Of the four proteins evaluated, wild type (WT) GPR and GPR E108Q produce the highest diffraction efficiencies, etamax, at approximately 1% for a 1.7 OD sample. GPR E108Q, however, requires 1-2 orders of magnitude less laser intensity to generate eta equivalent to WT GPR and BR D96N under similar conditions (as compared to literature values). WT BPR requires lower actinic powers than GPR but diffracts only about 30% as well. BPR E110Q performs the most poorly of the four, with etamax < 0.05% for a 1.4 OD film. The Kramers-Kronig transformation and Koglenik's coupled wave theory were used to predict the dispersion spectra and diffraction efficiency for the long M-state variants. To a first approximation, the gratings formed by all samples decay upon discontinuing the 520 nm actinic beams with a time constant characteristic of the appropriate intermediate: the N-like state for WT GPR and BPR and the M-state for GPR 108Q and BPR E110Q.

  14. Space Analogue Environments: Are the Populations Comparable?

    NASA Astrophysics Data System (ADS)

    Sandal, G. M.

    Background: Much of our present understanding about psychology in space is based on studies of groups operating in so-called analogue environments where personnel are exposed to many of the same stressors as those experienced by astronauts in space. One possible problem with extrapolating results is that personnel operating in various hazardous and confined environments might differ in characteristics influencing coping, interaction, and performance. The object of this study was to compare the psychological similarity of these populations in order to get a better understanding of whether this extrapolation is justifiable. The samples investigated include polar crossings (N= 22), personnel on Antarctic research stations (N= 183), several military occupations (N= 187), and participants in space simulation studies (N=20). Methods: Personnel in each of these environments were assessed using the Personality Characteristic Inventory (PCI) and Utrecht Coping List (UCL). The PCI is a multidimensional trait assessment battery that measures various aspects of achievement orientation and social competence. The UCL is a questionnaire designed to assess habitual coping strategies when encountering stressful or demanding situations. Results: Only minor differences in use of habitual coping strategies were evident across the different samples. In relation to personality scores, the military subjects and participants in space simulation studies indicated higher competitiveness and negative instrumentality compared to both the personnel on Antarctic research stations and participants in polar expedition. Among the personnel on Antarctic research stations, significant gender differences were found with women scoring lower on competitiveness, negative instrumentality and impatience/irritability. Compared to the other samples, the participants in polar expeditions were found to be more homogeneous in personality and no significant gender differences were evident on the traits that

  15. A nonlinear dynamic analogue model of substorms

    NASA Astrophysics Data System (ADS)

    Klimas, A. J.; Baker, D. N.; Roberts, D. A.; Fairfield, D. H.; Büchner, J.

    Linear prediction filter studies have shown that the magnetospheric response to energy transfer from the solar wind contains both directly driven and unloading components. These studies have also shown that the magnetospheric response is significantly nonlinear and, thus, the linear prediction filtering technique and other correlative techniques which assume a linear magnetospheric response cannot give a complete deacription of that response. Here, the solar wind-magnetosphere interaction is discussed within the framework of deterministic nonlinear dynamics. An earlier dripping faucet mechanical analogue to the magnetosphere is first reviewed and then the plasma physical counterpart to the mechanical model is constructed. A Faraday loop in the magnetotail is considered and the relationship of electric potentials on the loop to changes in the magnetic flux threading the loop is developed. This approach leads to a model of geomagnetic activity which is similar to the earlier mechanical model but described in terms of the geometry and plasma contents of the magnetotail. This Faraday loop response model contains analogues to both the directly driven and the storage-release magnetospheric responses and it includes, in a fundamental way, the inherent nonlinearity of the solar wind-magnetosphere system. It can be chancterized as a nonlinear, damped harmonic oscillator that is driven by the loading-unloading substorm cycle. The model is able to explain many of the features of the linear prediction filter results. In particular, at low geomagnetic activity levels the model exbibits the "regular dripping" response which provides an explanation for the unloading component at 1 hour lag in the linear prediction filters. Further, the model suggests that the disappearance of the unloading component in the linear prediction filters at high geomagnetic activity levels is due to a chaotic transition beyond which the loading-unloading mechanism becomes aperiodic. The model predicts

  16. Long-persistence blue phosphors

    NASA Technical Reports Server (NTRS)

    Yen, William M. (Inventor); Jia, Weiyi (Inventor); Lu, Lizhu (Inventor); Yuan, Huabiao (Inventor)

    2000-01-01

    This invention relates to phosphors including long-persistence blue phosphors. Phosphors of the invention are represented by the general formula: MO . mAl.sub.2 O.sub.3 :Eu.sup.2+,R.sup.3+ wherein m is a number ranging from about 1.6 to about 2.2, M is Sr or a combination of Sr with Ca and Ba or both, R.sup.3+ is a trivalent metal ion or trivalent Bi or a mixture of these trivalent ions, Eu.sup.2+ is present at a level up to about 5 mol % of M, and R.sup.3+ is present at a level up to about 5 mol % of M. Phosphors of this invention include powders, ceramics, single crystals and single crystal fibers. A method of manufacturing improved phosphors and a method of manufacturing single crystal phosphors are also provided.

  17. Tren-based analogues of bacillibactin: structure and stability.

    PubMed

    Dertz, Emily A; Xu, Jide; Raymond, Kenneth N

    2006-07-10

    Synthetic analogues were designed to highlight the effect of the glycine moiety of bacillibactin on the overall stability of the ferric complex as compared to synthetic analogues of enterobactin. Insertion of a variety of amino acids to catecholamide analogues based on a Tren (tris(2-aminoethyl)amine) backbone increased the overall acidity of the ligands, causing an enhancement of the stability of the resulting ferric complex as compared to TRENCAM. Solution thermodynamic behavior of these siderophores and their synthetic analogues was investigated through potentiometric and spectrophotometric titrations. X-ray crystallography, circular dichroism, and molecular modeling were used to determine the chirality and geometry of the ferric complexes of bacillibactin and its analogues. In contrast to the Tren scaffold, addition of a glycine to the catechol chelating arms causes an inversion of the trilactone backbone, resulting in opposite chiralities of the two siderophores and a destabilization of the ferric complex of bacillibactin compared to ferric enterobactin.

  18. Analogue Divider by Averaging a Triangular Wave

    NASA Astrophysics Data System (ADS)

    Selvam, Krishnagiri Chinnathambi

    2017-03-01

    A new analogue divider circuit by averaging a triangular wave using operational amplifiers is explained in this paper. The triangle wave averaging analog divider using operational amplifiers is explained here. The reference triangular waveform is shifted from zero voltage level up towards positive power supply voltage level. Its positive portion is obtained by a positive rectifier and its average value is obtained by a low pass filter. The same triangular waveform is shifted from zero voltage level to down towards negative power supply voltage level. Its negative portion is obtained by a negative rectifier and its average value is obtained by another low pass filter. Both the averaged voltages are combined in a summing amplifier and the summed voltage is given to an op-amp as negative input. This op-amp is configured to work in a negative closed environment. The op-amp output is the divider output.

  19. Naturalness in an emergent analogue spacetime.

    PubMed

    Liberati, Stefano; Visser, Matt; Weinfurtner, Silke

    2006-04-21

    Effective field theories (EFTs) have been widely used as a framework in order to place constraints on the Planck suppressed Lorentz violations predicted by various models of quantum gravity. There are, however, technical problems in the EFT framework when it comes to ensuring that small Lorentz violations remain small--this is the essence of the "naturalness" problem. Herein we present an "emergent" spacetime model, based on the "analogue gravity" program, by investigating a specific condensed-matter system. Specifically, we consider the class of two-component BECs subject to laser-induced transitions between the components, and we show that this model is an example for Lorentz invariance violation due to ultraviolet physics. Furthermore, our model explicitly avoids the naturalness problem, and makes specific suggestions regarding how to construct a physically reasonable quantum gravity phenomenology.

  20. Derivatisable Cyanobactin Analogues: A Semisynthetic Approach

    PubMed Central

    Oueis, Emilia; Adamson, Catherine; Mann, Greg; Ludewig, Hannes; Redpath, Philip; Migaud, Marie

    2015-01-01

    Abstract Many natural cyclic peptides have potent and potentially useful biological activities. Their use as therapeutic starting points is often limited by the quantities available, the lack of known biological targets and the practical limits on diversification to fine‐tune their properties. We report the use of enzymes from the cyanobactin family to heterocyclise and macrocyclise chemically synthesised substrates so as to allow larger‐scale syntheses and better control over derivatisation. We have made cyclic peptides containing orthogonal reactive groups, azide or dehydroalanine, that allow chemical diversification, including the use of fluorescent labels that can help in target identification. We show that the enzymes are compatible and efficient with such unnatural substrates. The combination of chemical synthesis and enzymatic transformation could help renew interest in investigating natural cyclic peptides with biological activity, as well as their unnatural analogues, as therapeutics. PMID:26507241

  1. A simple analogue of lung mechanics.

    PubMed

    Sherman, T F

    1993-12-01

    A model of the chest and lungs can be easily constructed from a bottle of water, a balloon, a syringe, a rubber stopper, glass and rubber tubing, and clamps. The model is a more exact analogue of the body than the classic apparatus of Hering in two respects: 1) the pleurae and intrapleural fluid are represented by water rather than air, and 2) the subatmospheric "intrapleural" pressure is created by the elasticity of the "lung" (balloon) rather than by a vacuum pump. With this model, students can readily see how the lung is inflated and deflated by movements of the "diaphragm and chest" (syringe plunger) and how intrapleural pressures change as this is accomplished.

  2. Blue collection bag after ileal diversion.

    PubMed

    Hildreth, T A; Cass, A S

    1978-02-01

    Five children with ileal diversions have shown asymptomatic blue staining of the urine collection bags. A tryptophan derivative (indican) in the urine that oxidizes to indigo blue on exposure to air is thought to be the cause of this benign transient phenomenon.

  3. Blue Skies, Coffee Creamer, and Rayleigh Scattering

    ERIC Educational Resources Information Center

    Liebl, Michael

    2010-01-01

    The first physical explanation of Earths blue sky was fashioned in 1871 by Lord Rayleigh. Many discussions of Rayleigh scattering and approaches to studying it both in and out of the classroom are available. Rayleigh scattering accounts for the blue color of the sky and the orange/red color of the Sun near sunset and sunrise, and a number of…

  4. Terrestrial Analogues for Lunar Impact Melt Flows

    NASA Technical Reports Server (NTRS)

    Neish, C. D.; Hamilton, C. W.; Hughes, S. S.; Nawotniak, S. Kobs; Garry, W. B.; Skok, J. R.; Elphic, R. C.; Schaefer, E.; Carter, L. M.; Bandfield, J. L.; Osinski, G. R.; Lim, D.; Heldmann, J. L.

    2016-01-01

    Lunar impact melt deposits have unique physical properties. They have among the highest observed radar returns at S-Band (12.6 cm wavelength), implying that they are rough at the decimeter scale. However, they are also observed in high-resolution optical imagery to be quite smooth at the meter scale. These characteristics distinguish them from well-studied terrestrial analogues, such as Hawaiian pahoehoe and ?a ?a lava flows. The morphology of impact melt deposits can be related to their emplacement conditions, so understanding the origin of these unique surface properties will help to inform us as to the circumstances under which they were formed. In this work, we seek to find a terrestrial analogue for well-preserved lunar impact melt flows by examining fresh lava flows on Earth. We compare the radar return and high-resolution topographic variations of impact melt flows to terrestrial lava flows with a range of surface textures. The lava flows examined in this work range from smooth Hawaiian pahoehoe to transitional basaltic flows at Craters of the Moon (COTM) National Monument and Preserve in Idaho to rubbly and spiny pahoehoe-like flows at the recent eruption at Holuhraun in Iceland. The physical properties of lunar impact melt flows appear to differ from those of all the terrestrial lava flows studied in this work. This may be due to (a) differences in post-emplacement modification processes or (b) fundamental differences in the surface texture of the melt flows due to the melts' unique emplacement and/or cooling environment. Information about the surface properties of lunar impact melt deposits will be critical for future landed missions that wish to sample these materials.

  5. Natural analogues of nuclear waste glass corrosion.

    SciTech Connect

    Abrajano, T.A. Jr.; Ebert, W.L.; Luo, J.S.

    1999-01-06

    This report reviews and summarizes studies performed to characterize the products and processes involved in the corrosion of natural glasses. Studies are also reviewed and evaluated on how well the corrosion of natural glasses in natural environments serves as an analogue for the corrosion of high-level radioactive waste glasses in an engineered geologic disposal system. A wide range of natural and experimental corrosion studies has been performed on three major groups of natural glasses: tektite, obsidian, and basalt. Studies of the corrosion of natural glass attempt to characterize both the nature of alteration products and the reaction kinetics. Information available on natural glass was then compared to corresponding information on the corrosion of nuclear waste glasses, specifically to resolve two key questions: (1) whether one or more natural glasses behave similarly to nuclear waste glasses in laboratory tests, and (2) how these similarities can be used to support projections of the long-term corrosion of nuclear waste glasses. The corrosion behavior of basaltic glasses was most similar to that of nuclear waste glasses, but the corrosion of tektite and obsidian glasses involves certain processes that also occur during the corrosion of nuclear waste glasses. The reactions and processes that control basalt glass dissolution are similar to those that are important in nuclear waste glass dissolution. The key reaction of the overall corrosion mechanism is network hydrolysis, which eventually breaks down the glass network structure that remains after the initial ion-exchange and diffusion processes. This review also highlights some unresolved issues related to the application of an analogue approach to predicting long-term behavior of nuclear waste glass corrosion, such as discrepancies between experimental and field-based estimates of kinetic parameters for basaltic glasses.

  6. Terrestrial analogues for lunar impact melt flows

    NASA Astrophysics Data System (ADS)

    Neish, C. D.; Hamilton, C. W.; Hughes, S. S.; Nawotniak, S. Kobs; Garry, W. B.; Skok, J. R.; Elphic, R. C.; Schaefer, E.; Carter, L. M.; Bandfield, J. L.; Osinski, G. R.; Lim, D.; Heldmann, J. L.

    2017-01-01

    Lunar impact melt deposits have unique physical properties. They have among the highest observed radar returns at S-Band (12.6 cm wavelength), implying that they are rough at the decimeter scale. However, they are also observed in high-resolution optical imagery to be quite smooth at the meter scale. These characteristics distinguish them from well-studied terrestrial analogues, such as Hawaiian pāhoehoe and ´a´ā lava flows. The morphology of impact melt deposits can be related to their emplacement conditions, so understanding the origin of these unique surface properties will help to inform us as to the circumstances under which they were formed. In this work, we seek to find a terrestrial analogue for well-preserved lunar impact melt flows by examining fresh lava flows on Earth. We compare the radar return and high-resolution topographic variations of impact melt flows to terrestrial lava flows with a range of surface textures. The lava flows examined in this work range from smooth Hawaiian pāhoehoe to transitional basaltic flows at Craters of the Moon (COTM) National Monument and Preserve in Idaho to rubbly and spiny pāhoehoe-like flows at the recent eruption at Holuhraun in Iceland. The physical properties of lunar impact melt flows appear to differ from those of all the terrestrial lava flows studied in this work. This may be due to (a) differences in post-emplacement modification processes or (b) fundamental differences in the surface texture of the melt flows due to the melts' unique emplacement and/or cooling environment. Information about the surface properties of lunar impact melt deposits will be critical for future landed missions that wish to sample these materials.

  7. Current european regulatory perspectives on insulin analogues

    PubMed Central

    2011-01-01

    Insulin analogues are increasingly considered as an alternative to human insulin in the therapy of diabetes mellitus. Insulin analogues (IAs) are chemically different from human insulin and may have different pharmacokinetic or pharmacodynamic properties. The significance of the modifications of the insulin molecule for the safety profile of IAs must be considered. This review describes the regulatory procedure and the expectations for the scientific content of European marketing authorization applications for innovative IAs submitted to the European Medicines Agency. Particular consideration is given to a potential cancer hazard. Specific regulatory guidance on how to address a possible carcinogenic or tumor promoting effect of innovative IAs in non-clinical studies is available. After marketing authorization, the factual access of patients to the new product will be determined to great extent by health technology assessment bodies, reimbursement decisions and the price. Whereas the marketing authorization is a European decision, pricing and reimbursement are national or regional responsibilities. The assessment of benefit and risk by the European Medicines Agency is expected to influence future decisions on price and reimbursement on a national or regional level. Collaborations between regulatory agencies and health technology assessment bodies have been initiated on European and national level to facilitate the use of the European Medicines Agency's benefit risk assessment as basis on which to build the subsequent health technology assessment. The option for combined or joint scientific advice procedures with regulators and health technology assessment bodies on European level or on a national level in several European Member States may help applicants to optimize their development program and dossier preparation in regard of both European marketing authorization application and reimbursement decisions. PMID:21736748

  8. Elementary theorems regarding blue isocurvature perturbations

    NASA Astrophysics Data System (ADS)

    Chung, Daniel J. H.; Yoo, Hojin

    2015-04-01

    Blue CDM-photon isocurvature perturbations are attractive in terms of observability and may be typical from the perspective of generic mass relations in supergravity. We present and apply three theorems useful for blue isocurvature perturbations arising from linear spectator scalar fields. In the process, we give a more precise formula for the blue spectrum associated with the axion model of Kasuya and Kawasaki [Axion Isocurvature Fluctuations with Extremely Blue Spectrum, Phys. Rev. D 80, 023516 (2009).], which can in a parametric corner give a factor of O (10 ) correction. We explain how a conserved current associated with Peccei-Quinn symmetry plays a crucial role and explicitly plot several example spectra including the breaks in the spectra. We also resolve a little puzzle arising from a naive multiplication of isocurvature expression that sheds light on the gravitational imprint of the adiabatic perturbations on the fields responsible for blue isocurvature fluctuations.

  9. Featured Molecules: Ascorbic Acid and Methylene Blue

    NASA Astrophysics Data System (ADS)

    Coleman, William F.; Wildman, Randall J.

    2003-05-01

    The WebWare molecules of the month for May are featured in several articles in this issue. "Arsenic: Not So Evil After All?" discusses the pharmaceutical uses of methylene blue and its development as the first synthetic drug used against a specific disease. The JCE Classroom Activity "Out of the Blue" and the article "Greening the Blue Bottle" feature methylene blue and ascorbic acid as two key ingredients in the formulation of the blue bottle. You can also see a colorful example of these two molecules in action on the cover. "Sailing on the 'C': A Vitamin Titration with a Twist" describes an experiment to determine the vitamin C (ascorbic acid) content of citrus fruits and challenges students, as eighteenth-century sea captains, to decide the best fruit to take on a long voyage. Fully manipulable (Chime) versions of these and other molecules are available at Only@JCE Online.

  10. Analogues of uracil nucleosides with intrinsic fluorescence (NIF-analogues): synthesis and photophysical properties.

    PubMed

    Segal, Meirav; Fischer, Bilha

    2012-02-28

    Uridine cannot be utilized as fluorescent probe due to its extremely low quantum yield. For improving the uracil fluorescence characteristics we extended the natural chromophore at the C5 position by coupling substituted aromatic rings directly or via an alkenyl or alkynyl linker to create fluorophores. Extension of the uracil base was achieved by treating 5-I-uridine with the appropriate boronic acid under the Suzuki coupling conditions. Analogues containing an alkynyl linker were obtained from 5-I-uridine and the suitable boronic acid in a Sonogashira coupling reaction. The uracil fluorescent analogues proposed here were designed to satisfy the following requirements: a minimal chemical modification at a position not involved in base-pairing, resulting in relatively long absorption and emission wavelengths and high quantum yield. 5-((4-Methoxy-phenyl)-trans-vinyl)-2'-deoxy-uridine, 6b, was found to be a promising fluorescent probe. Probe 6b exhibits a quantum yield that is 3000-fold larger than that of the natural chromophore (Φ 0.12), maximum emission (478 nm) which is 170 nm red shifted as compared to uridine, and a Stokes shift of 143 nm. In addition, since probe 6b adopts the anti conformation and S sugar puckering favored by B-DNA, it makes a promising nucleoside analogue to be incorporated in an oligonucleotide probe for detection of genetic material.

  11. 1. GENERAL VIEW OF ENTRANCE TO BLUE RIDGE TUNNEL (LEFT) ...

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

    1. GENERAL VIEW OF ENTRANCE TO BLUE RIDGE TUNNEL (LEFT) FROM SOUTHEAST. ORIGINAL BLUE RIDGE R.R. (CROZET) TUNNEL IS VISIBLE AT RIGHT. - Chesapeake & Ohio Railroad, Blue Ridge Tunnel, Highway 250 at Rockfish Gap, Afton, Nelson County, VA

  12. Design of multi-epitope, analogue-based cancer vaccines.

    PubMed

    Fikes, John D; Sette, Alessandro

    2003-09-01

    The current objective of our cancer programme is to develop an effective vaccine based on rationally designed T cell epitope analogues, for use in the adjuvant setting for non-small cell lung cancer (NSCLC) and colon cancer. Analogue epitopes, enhanced for either human leukocyte antigen (HLA) binding or T cell receptor (TCR) signalling, have been shown to be more effective at breaking immunological tolerance than cognate wild-type epitopes. Although encouraging early-phase clinical data has been obtained by others using a limited number of HLA-A2-restricted epitope analogues, the clinical benefits and immune correlates for vaccines comprised of multiple epitope analogues restricted by multiple HLA supertypes remains to be investigated. Clinical studies are currently being conducted on EP-2101, a prototype vaccine that delivers multiple HLA-A2-restricted analogue epitopes. In parallel, fixed anchor and heteroclitic analogues restricted by three other commonly expressed HLA supertypes are being identified. These analogues will be incorporated into future vaccines including optimised minigenes (epigenes) and tested in preclinical and clinical studies addressing various different cancer indications.

  13. Functionalized Congener Approach to Muscarinic Antagonists: Analogues of Pirenzepine

    PubMed Central

    Karton, Yishai; Bradbury, Barton J.; Baumgold, Jesse; Paek, Robert; Jacobson, Kenneth A.

    2012-01-01

    The M1-selective muscarinic receptor antagonist pirenzepine (5,11-dihydro-11-[(4-methyl-1-piperazinyl)acetyl]-6H-pyrido[2,3-b] [1,4]benzodiazepin-6-one) was derivatized to explore points of attachment of functionalized side chains for the synthesis of receptor probes and ligands for affinity chromatography. The analogues prepared were evaluated in competitive binding assays versus [3H]-N-methylscopolamine at four muscarinic receptor subtypes (m1AChR-m4AChR) in membranes from rat heart tissue and transfected A9L cells. 9-(Hydroxymethyl)pirenzepine, 8-(methylthio)pirenzepine, and a series of 8-aminosulfonyl derivatives were synthesized. Several 5-substituted analogues of pirenzepine also were prepared. An alternate series of analogues substituted on the 4-position of the piperazine ring was prepared by reaction of 4-desmethylpirenzepine with various electrophiles. An N-chloroethyl analogue of pirenzepine was shown to form a reactive aziridine species in aqueous buffer yet failed to affinity label muscarinic receptors. Within a series of aminoalkyl analogues, the affinity increased as the length of the alkyl chain increased. Shorter chain analogues were generally much less potent than pirenzepine, and longer analogues (7–10 carbons) were roughly as potent as pirenzepine at m1 receptors, but were nonselective. Depending on the methylene chain length, acylation or alkyl substitution of the terminal amine also influenced the affinity at muscarinic receptors. PMID:2066986

  14. Can greening of aquaculture sequester blue carbon?

    PubMed

    Ahmed, Nesar; Bunting, Stuart W; Glaser, Marion; Flaherty, Mark S; Diana, James S

    2016-11-15

    Globally, blue carbon (i.e., carbon in coastal and marine ecosystems) emissions have been seriously augmented due to the devastating effects of anthropogenic pressures on coastal ecosystems including mangrove swamps, salt marshes, and seagrass meadows. The greening of aquaculture, however, including an ecosystem approach to Integrated Aquaculture-Agriculture (IAA) and Integrated Multi-Trophic Aquaculture (IMTA) could play a significant role in reversing this trend, enhancing coastal ecosystems, and sequestering blue carbon. Ponds within IAA farming systems sequester more carbon per unit area than conventional fish ponds, natural lakes, and inland seas. The translocation of shrimp culture from mangrove swamps to offshore IMTA could reduce mangrove loss, reverse blue carbon emissions, and in turn increase storage of blue carbon through restoration of mangroves. Moreover, offshore IMTA may create a barrier to trawl fishing which in turn could help restore seagrasses and further enhance blue carbon sequestration. Seaweed and shellfish culture within IMTA could also help to sequester more blue carbon. The greening of aquaculture could face several challenges that need to be addressed in order to realize substantial benefits from enhanced blue carbon sequestration and eventually contribute to global climate change mitigation.

  15. [Biodegradation of reactive turquoise blue].

    PubMed

    Fu, L; Wen, X; Xu, L; Qian, Y

    2001-07-01

    In this study, the anaerobic degradation and the aerobic degradation of a kind of reactive dye--Reactive Turquoise Blue(RTB) were compared. The results proved that anaerobic sludge could only decompose RTB in the presence of glucose while aerobic sludge decomposed RTB with or without the presence of glucose (RTB of 20 mg/L was reduced by 37.4% through 24 hours' aerobic treatment with RTB as sole carbon source). The enhancement of glucose concentration was beneficial for both anaerobic and aerobic degradation of RTB: the anaerobic and the aerobic removal efficiencies were respectively 81.5% and 73.6% with RTB of 20 mg/L and glucose of 1200 mg/L. In the influent RTB concentration also had influence on the activity of anaerobic and aerobic microorganisms. When glucose concentration was 800 mg/L or 1200 mg/L and RTB concentration was 20 mg/L to 100 mg/L, anaerobic removal efficiency of RTB was higher than aerobic removal efficiency by 4.9%-27.2%, which meant that anaerobic bacteria is more powerful than aerobic bacteria in terms of RTB removal.

  16. Blue jays nest in an unusual structure

    USGS Publications Warehouse

    Muths, Erin L.; Lyons, Curtis P.; Sedgwick, James A.

    2007-01-01

    We describe a successful Blue Jay (Cyanocitta cristata) nest in an unusual structure on the side of a building.  The nest was located near the edge of the species' range along the Front Range of the Rocky Mountains in Colorado.  The nest was completely obvious, suggesting that the structure itself provided adequate cover and sercurity for the jays.  Blue Jays appear to be declining in some areas of the United States such as the Southeast.  Structures such as the one we describe may be more useful in attracting Blue Jays than the nesting platforms available commercially.

  17. A chemoselective and continuous synthesis of m-sulfamoylbenzamide analogues

    PubMed Central

    Verlee, Arno; Heugebaert, Thomas; van der Meer, Tom; Kerchev, Pavel I; Van Breusegem, Frank

    2017-01-01

    For the synthesis of m-sulfamoylbenzamide analogues, small molecules which are known for their bioactivity, a chemoselective procedure has been developed starting from m-(chlorosulfonyl)benzoyl chloride. Although a chemoselective process in batch was already reported, a continuous-flow process reveals an increased selectivity at higher temperatures and without catalysts. In total, 15 analogues were synthesized, using similar conditions, with yields ranging between 65 and 99%. This is the first automated and chemoselective synthesis of m-sulfamoylbenzamide analogues. PMID:28326139

  18. Mars on Earth: soil analogues for future Mars missions

    NASA Astrophysics Data System (ADS)

    Marlow, Jeffrey J.; Martins, Zita; Sephton, Mark A.

    2008-04-01

    Preparations for missions to Mars are a major concern for scientists. Predicting how equipment and experiments will perform on the planet is difficult because tests are restricted to Earth. Mars soil analogues are being used to solve this problem. These terrestrial materials are chemically and physically similar to martian soils and, because they contain unusual minerals and trace amounts of organic matter, are scientifically interesting in their own right. However, no current analogue is appropriate for all necessary tests. Here we describe Mars soil analogues, identify limitations and suggest the need for new Mars simulants.

  19. Synthesis, antiarrhythmic activity, and toxicological evaluation of mexiletine analogues.

    PubMed

    Roselli, Mariagrazia; Carocci, Alessia; Budriesi, Roberta; Micucci, Matteo; Toma, Maddalena; Di Cesare Mannelli, Lorenzo; Lovece, Angelo; Catalano, Alessia; Cavalluzzi, Maria Maddalena; Bruno, Claudio; De Palma, Annalisa; Contino, Marialessandra; Perrone, Maria Grazia; Colabufo, Nicola Antonio; Chiarini, Alberto; Franchini, Carlo; Ghelardini, Carla; Habtemariam, Solomon; Lentini, Giovanni

    2016-10-04

    Four mexiletine analogues have been tested for their antiarrhythmic, inotropic, and chronotropic effects on isolated guinea pig heart tissues and to assess calcium antagonist activity, in comparison with the parent compound mexiletine. All analogues showed from moderate to high antiarrhythmic activity. In particular, three of them (1b,c,e) were more active and potent than the reference drug, while exhibiting only modest or no negative inotropic and chronotropic effects and vasorelaxant activity, thus showing high selectivity of action. All compounds showed no cytotoxicity and 1b,c,d did not impair motor coordination. All in, these new analogues exhibit an interesting cardiovascular profile and deserve further investigation.

  20. Mammary analogue secretory carcinoma mimicking salivary adenoma.

    PubMed

    Williams, Lindsay; Chiosea, Simion I

    2013-12-01

    Mammary analogue secretory carcinoma (MASC) is a recently described salivary gland tumor characterized by ETV6 translocation. It appears that prior studies have identified MASC by reviewing salivary gland carcinomas, such as acinic cell carcinoma and adenocarcinoma, not otherwise specified. To address the possibility of MASC mimicking benign salivary neoplasms we reviewed 12 salivary gland (cyst)adenomas diagnosed prior to the discovery of MASC. One encapsulated (cyst)adenoma of the parotid gland demonstrated features of MASC. The diagnosis was confirmed by fluorescence in situ hybridization with an ETV6 break-apart probe. An unusual complex pattern of ETV6 rearrangement with duplication of the telomeric/distal ETV6 probe was identified. This case illustrates that MASC may mimic salivary (cyst)adenomas. To more accurately assess true clinical and morphologic spectrum of MASC, future studies may have to include review of salivary (cyst)adenomas. The differential diagnosis of MASC may have to be expanded to include cases resembling salivary (cyst)adenomas.

  1. Fluorescent polyene ceramide analogues as membrane probes.

    PubMed

    Nieves, Ingrid; Artetxe, Ibai; Abad, José Luis; Alonso, Alicia; Busto, Jon V; Fajarí, Lluís; Montes, L Ruth; Sot, Jesús; Delgado, Antonio; Goñi, Félix M

    2015-03-03

    Three ceramide analogues have been synthesized, with sphingosine-like chains containing five conjugated double bonds. Pentaene I has an N-palmitoyl acyl chain, while the other two pentaenes contain also a doxyl radical, respectively, at C5 (Penta5dox) and at C16 (Penta16dox) positions of the N-acyl chain. Pentaene I maximum excitation and emission wavelengths in a phospholipid bilayer are 353 and 478 nm, respectively. Pentaene I does not segregate from the other lipids in the way natural ceramide does, but rather mixes with them in a selective way according to the lipid phases involved. Fluorescence confocal microscopy studies show that when lipid domains in different physical states coexist, Pentaene I emission is higher in gel than in fluid domains, and in liquid-ordered than in liquid-disordered areas. Electron paramagnetic resonance of the pentaene doxyl probes confirms that these molecules are sensitive to the physical state of the bilayer. Calorimetric and fluorescence quenching experiments suggest that the lipids under study orient themselves in lipid bilayers with their polar moieties located at the lipid-water interface. The doxyl radical in the N-acyl chain quenches the fluorescence of the pentaene group when in close proximity. Because of this property, Penta16dox can detect gel-fluid transitions in phospholipids. The availability of probes for lipids in the gel phase is important in view of novel evidence for the existence of gel microdomains in cell membranes.

  2. Actions of Thyroid Hormone Analogues on Chemokines

    PubMed Central

    Glinsky, Gennadi V.

    2016-01-01

    The extracellular domain of plasma membrane integrin αvβ3 contains a receptor for thyroid hormone (L-thyroxine, T4; 3,5,3′-triiodo-L-thyronine, T3); this receptor also binds tetraiodothyroacetic acid (tetrac), a derivative of T4. Tetrac inhibits the binding of T4 and T3 to the integrin. Fractalkine (CX3CL1) is a chemokine relevant to inflammatory processes in the CNS that are microglia-dependent but also important to normal brain development. Expression of the CX3CL1 gene is downregulated by tetrac, suggesting that T4 and T3 may stimulate fractalkine expression. Independently of its specific receptor (CX3CR1), fractalkine binds to αvβ3 at a site proximal to the thyroid hormone-tetrac receptor and changes the physical state of the integrin. Tetrac also affects expression of the genes for other CNS-relevant chemokines, including CCL20, CCL26, CXCL2, CXCL3, and CXCL10. The chemokine products of these genes are important to vascularity of the brain, particularly of the choroid plexus, to inflammatory processes in the CNS and, in certain cases, to neuroprotection. Thyroid hormones are known to contribute to regulation of each of these CNS functions. We propose that actions of thyroid hormone and hormone analogues on chemokine gene expression contribute to regulation of inflammatory processes in brain and of brain blood vessel formation and maintenance. PMID:27493972

  3. Blue Ribbon Commission Tour of Hanford Site

    SciTech Connect

    Paul Saueressig

    2010-07-14

    The Blue Ribbon Commission on America's Nuclear Future toured the Department of Energy's Hanford Site on July 14, 2010. Commission members, invited guests, and members of the public visited facilities that store high-level, radioactive waste.

  4. Blue Origin Conducts Pad Escape Test

    NASA Video Gallery

    Blue Origin conducted a successful pad escape test Oct. 19 at the company's West Texas launch site, firing its pusher escape motor and launching a full-scale suborbital crew capsule from a simulate...

  5. Blue Ribbon Panel 2016 Video Playlist

    Cancer.gov

    Blue Ribbon Panel members discuss recommendations from the panel report that was presented to the National Cancer Advisory Board. The playlist includes an overview video and 10 videos on the specific recommendations.

  6. Blue Ribbon Commission Tour of Hanford Site

    ScienceCinema

    Paul Saueressig

    2016-07-12

    The Blue Ribbon Commission on America's Nuclear Future toured the Department of Energy's Hanford Site on July 14, 2010. Commission members, invited guests, and members of the public visited facilities that store high-level, radioactive waste.

  7. Blue Origin Tests BE-3 Engine

    NASA Video Gallery

    Blue Origin successfully fires the thrust chamber assembly for its new 100,000 pound thrust BE-3 liquid oxygen, liquid hydrogen rocket engine. As part of the company's Reusable Booster System (RBS)...

  8. Phototherapy with turquoise versus blue light.

    PubMed

    Ebbesen, F; Agati, G; Pratesi, R

    2003-09-01

    Preterm jaundiced infants were treated by phototherapy with a new turquoise fluorescent lamp. This was more effective in reducing plasma total bilirubin in relation to light irradiance than the ubiquitously used blue fluorescent lamp.

  9. Blue Ribbon Panel Report Cover Letter

    Cancer.gov

    The letter from NCI Acting Director Douglas R. Lowy, M.D., to Vice President Biden that accompanied the Blue Ribbon Panel final report, thanking the Vice President for his commitment to and leadership of the Cancer Moonshot.

  10. Sulphur Spring: Busy Intersection and Possible Martian Analogue

    NASA Technical Reports Server (NTRS)

    Nankivell, A.; Andre, N.; Thomas-Keprta, K.; Allen, C.; McKay, D.

    2000-01-01

    Life in extreme environments exhibiting conditions similar to early Earth and Mars, such as Sulphur Spring, may harbor microbiota serving as both relics from the past as well as present day Martian analogues.

  11. From BPA to its analogues: Is it a safe journey?

    PubMed

    Usman, Afia; Ahmad, Masood

    2016-09-01

    Bisphenol-A (BPA) is one of the most abundant synthetic chemicals in the world due to its uses in plastics. Its widespread exposure vis-a-vis low dose effects led to a reduction in its safety dose and imposition of ban on its use in infant feeding bottles. This restriction paved the way for the gradual market entry of its analogues. However, their structural similarity to BPA has put them under surveillance for endocrine disrupting potential. The application of these analogues is increasing and so are the studies reporting their toxicity. This review highlights the reasons which led to the ban of BPA and also reports the exposure and toxicological data available on its analogues. Hence, this compilation is expected to answer in a better way whether the replacement of BPA by these analogues is safer or more harmful?

  12. Cell-cycle analyses using thymidine analogues in fission yeast.

    PubMed

    Anda, Silje; Boye, Erik; Grallert, Beata

    2014-01-01

    Thymidine analogues are powerful tools when studying DNA synthesis including DNA replication, repair and recombination. However, these analogues have been reported to have severe effects on cell-cycle progression and growth, the very processes being investigated in most of these studies. Here, we have analyzed the effects of 5-ethynyl-2'-deoxyuridine (EdU) and 5-Chloro-2'-deoxyuridine (CldU) using fission yeast cells and optimized the labelling procedure. We find that both analogues affect the cell cycle, but that the effects can be mitigated by using the appropriate analogue, short pulses of labelling and low concentrations. In addition, we report sequential labelling of two consecutive S phases using EdU and 5-bromo-2'-deoxyuridine (BrdU). Furthermore, we show that detection of replicative DNA synthesis is much more sensitive than DNA-measurements by flow cytometry.

  13. Weather and event generators based on analogues of atmospheric circulation

    NASA Astrophysics Data System (ADS)

    Yiou, Pascal

    2015-04-01

    Analogues of atmospheric circulation have had numerous applications on weather prediction, climate reconstructions and detection/attribution analyses. A stochastic weather generator based on circulation analogues was recently proposed by Yiou (2014) to simulate sequences of European temperatures. One of the features of this weather generator is that it preserves the spatial and temporal structures of the climate variables to be simulated. This method is flexible enough to be combined efficiently with a storm detection algorithm in order to generate large catalogues of high impact extra-tropical storms that hit Europe. I will present the gist of the method of circulation analogues and some performances. Two promising applications for weather generators based on this method (ensemble climate prediction and extra-tropical storms) will be tested. References Yiou, P.: AnaWEGE: a weather generator based on analogues of atmospheric circulation, Geosci. Model Dev., 7, 531-543, doi:10.5194/gmd-7-531-2014, 2014.

  14. Effect of glutamate analogues on brain tumor cell lines.

    PubMed

    Campbell, G L; Bartel, R; Freidman, H S; Bigner, D D

    1985-10-01

    Glutamate analogues have been used in many different experimental approaches in neurobiology. A small number of these analogues have been classified as gliotoxic. We have examined the effect of seven glutamate analogues (five gliotoxic and two neurotoxic) on the growth and viability of four human glioma cell lines, one human medulloblastoma cell line, and one human sarcoma cell line. Aminoadipic acid and homocysteic acid predominantly affected the growth of two glioma cell lines in the presence of 4 mM glutamine. Phosphonobutyric acid predominantly affected the other two glioma cell lines and the medulloblastoma cell line in the presence of 4 mM glutamine. In medium containing no glutamine, all three analogues had marked effects on all the cell lines except the sarcoma cell line. These effects were dose dependent. We postulate that these results can in part be explained on the basis of metabolic compartmentalization.

  15. A Non-Verbal Analogue to the Verbal Transformation Effect

    ERIC Educational Resources Information Center

    Lass, Norman J.; And Others

    1973-01-01

    Investigates the effectiveness of non-speech auditory stimuli in eliciting transformations analogous to those reported for speech stimuli to determine if a non-verbal analogue to the verbal transformation effect exists. (DD)

  16. Si-based blue light emitting diode

    NASA Astrophysics Data System (ADS)

    Namavar, Fereydoon

    1994-05-01

    Phase 1 results demonstrated for the first time a strong, stable blue-green emission from C-implanted red-emitting porous silicon. The objective of Phase 1 was to obtain blue-green emission from porous Si structure either by increasing the bandgap of the substrate by growth of Si-C random alloys prior to forming nanostructures with quantum confined properties, or by increasing the confinement energy of red-emitting Si nanostructures. Porous structures fabricated from group 4 alloys epitaxially grown by chemical vapor deposition (CVD) resulted in an enhancement in light emission of about one order of magnitude after incorporation of a very small amount of carbon in the epitaxial grown films. Strong blue-green light emission was observed by the naked eye from C-implanted and annealed porous Si. Using AlGaAs as a reference, we observed that the intensity of blue-green emission was one order of magnitude higher than that of the original red-emitting porous Si. Catholuminescence measurements of our samples performed at the University of Colorado show blue emission at 1.80 eV and 2.80 eV. Fourier transform infrared (FTIR) spectra of a blue-green emitting porous structure shows an IR absorption line identical to that of SiC and electron diffraction studies clearly show reflections corresponding to beta-SiC. Phase 1 results indicate that blue-green light is from SiC nanostructures with quantum confined properties. This material may be used to fabricate blue light-emitting Si-based devices which can be easily integrated into Si technology.

  17. Phytochemistry: structure of the blue cornflower pigment.

    PubMed

    Shiono, Masaaki; Matsugaki, Naohiro; Takeda, Kosaku

    2005-08-11

    The same anthocyanin pigment makes roses red but cornflowers blue, a phenomenon that has so far not been entirely explained. Here we describe the X-ray crystal structure of the cornflower pigment, which reveals that its blue colour arises from a complex of six molecules each of anthocyanin and flavone, with one ferric iron, one magnesium and two calcium ions. We believe that this tetrametal complex may represent a previously undiscovered type of supermolecular pigment.

  18. Amphiphilic Tobramycin Analogues as Antibacterial and Antifungal Agents

    PubMed Central

    Shrestha, Sanjib K.; Fosso, Marina Y.; Green, Keith D.

    2015-01-01

    In this study, we investigated the in vitro antifungal activities, cytotoxicities, and membrane-disruptive actions of amphiphilic tobramycin (TOB) analogues. The antifungal activities were established by determination of MIC values and in time-kill studies. Cytotoxicity was evaluated in mammalian cell lines. The fungal membrane-disruptive action of these analogues was studied by using the membrane-impermeable dye propidium iodide. TOB analogues bearing a linear alkyl chain at their 6″-position in a thioether linkage exhibited chain length-dependent antifungal activities. Analogues with C12 and C14 chains showed promising antifungal activities against tested fungal strains, with MIC values ranging from 1.95 to 62.5 mg/liter and 1.95 to 7.8 mg/liter, respectively. However, C4, C6, and C8 TOB analogues and TOB itself exhibited little to no antifungal activity. Fifty percent inhibitory concentrations (IC50s) for the most potent TOB analogues (C12 and C14) against A549 and Beas 2B cells were 4- to 64-fold and 32- to 64-fold higher, respectively, than their antifungal MIC values against various fungi. Unlike conventional aminoglycoside antibiotics, TOB analogues with alkyl chain lengths of C12 and C14 appear to inhibit fungi by inducing apoptosis and disrupting the fungal membrane as a novel mechanism of action. Amphiphilic TOB analogues showed broad-spectrum antifungal activities with minimal mammalian cell cytotoxicity. This study provides novel lead compounds for the development of antifungal drugs. PMID:26033722

  19. Adjuvant properties of a simplified C32 monomycolyl glycerol analogue.

    PubMed

    Bhowruth, Veemal; Minnikin, David E; Agger, Else Marie; Andersen, Peter; Bramwell, Vincent W; Perrie, Yvonne; Besra, Gurdyal S

    2009-04-01

    A simplified C(32) monomycolyl glycerol (MMG) analogue demonstrated enhanced immunostimulatory activity in a dioctadecyl ammonium bromide (DDA)/Ag85B-ESAT-6 formulation. Elevated levels of IFN-gamma and IL-6 were produced in spleen cells from mice immunised with a C(32) MMG analogue comparable activity to the potent Th1 adjuvant, trehalose 6,6'-di-behenate (TDB).

  20. Semisynthesis of salviandulin E analogues and their antitrypanosomal activity.

    PubMed

    Aoyagi, Yutaka; Fujiwara, Koji; Yamazaki, Akira; Sugawara, Naoko; Yano, Reiko; Fukaya, Haruhiko; Hitotsuyanagi, Yukio; Takeya, Koichi; Ishiyama, Aki; Iwatsuki, Masato; Otoguro, Kazuhiko; Yamada, Haruki; Ōmura, Satoshi

    2014-01-15

    A series of analogues of salviandulin E, a rearranged neoclerodane diterpene originally isolated from Salvia leucantha (Lamiaceae), were prepared and their in vitro activity against Trypanosoma brucei brucei was evaluated with currently used therapeutic drugs as positive controls. One of the 19 compounds prepared and assayed in the present study, butanoyl 3,4-dihydrosalviandulin E analogue was found to be a possible candidate for an antitrypanosomal drug with fairly strong antitrypanosomal activity and lower cytotoxicity.

  1. Catalytic antioxidants: regenerable tellurium analogues of vitamin E.

    PubMed

    Singh, Vijay P; Poon, Jia-fei; Engman, Lars

    2013-12-20

    In an effort to improve the chain-breaking capacity of the natural antioxidants, an octyltelluro group was introduced next to the phenolic moiety in β- and δ-tocopherol. The new vitamin E analogues quenched peroxyl radicals more efficiently than α-tocopherol and were readily regenerable by aqueous N-acetylcysteine in a simple membrane model composed of a stirring chlorobenzene/water two-phase system. The novel tocopherol analogues could also mimic the action of the glutathione peroxidase enzymes.

  2. Analogue and digital linear modulation techniques for mobile satellite

    NASA Technical Reports Server (NTRS)

    Whitmarsh, W. J.; Bateman, A.; Mcgeehan, J. P.

    1990-01-01

    The choice of modulation format for a mobile satellite service is complex. The subjective performance is summarized of candidate schemes and voice coder technologies. It is shown that good performance can be achieved with both analogue and digital voice systems, although the analogue system gives superior performance in fading. The results highlight the need for flexibility in the choice of signaling format. Linear transceiver technology capable of using many forms of narrowband modulation is described.

  3. Eye damage control by reduced blue illumination.

    PubMed

    Ueda, Toshihiko; Nakanishi-Ueda, Takako; Yasuhara, Hajime; Koide, Ryohei; Dawson, William W

    2009-12-01

    The aim of this study was to demonstrate that a blue light and ultraviolet cut-off filter (blue filter) could reduce short-wavelength retina/RPE damage threshold by a continuous spectrum source. Sixteen normal eyes of two rhesus monkeys and six cynomolgus monkeys were subjected to macular irradiation of 20, 24, 27.4, 30, 35, 45, 50 and 60 J/cm(2) energy densities. The values of energy density were measured before the blue filter. Lesions were measured before and at 2 and 30 days after irradiation of a 2.8 mm diameter region within the macular arcade. Measures were fundoscopy, fluorescein angiography and long wavelength scanning by the Heidelberg Retinal Tomograph (HRT) unit. The lesions, which were produced, were scored and compared to irradiant energy density of the blue LED (NSPB500S, Nichia, Tokushima, Japan). The exposure at the 20 J/cm(2) produced no detectable result at 2 or 30 days. Exposure at 35 J/cm(2) showed definite lesion production without blue filter. With the filter added there was one indication of minor change. At 60 J/cm(2) there was extensive heavy, enduring damage without the filter and with the filter damage was present but was significantly attenuated. These results strongly support the conclusion that the blue filter attenuation reduces the frequency of damage by exposure. This experimental system is a useful model for normal human eye aging and continuous spectrum environment irradiance.

  4. Vibrio azureus emits blue-shifted light via an accessory blue fluorescent protein.

    PubMed

    Yoshizawa, Susumu; Karatani, Hajime; Wada, Minoru; Kogure, Kazuhiro

    2012-04-01

    Luminous marine bacteria usually emit bluish-green light with a peak emission wavelength (λ(max) ) at about 490 nm. Some species belonging to the genus Photobacterium are exceptions, producing an accessory blue fluorescent protein (lumazine protein: LumP) that causes a blue shift, from λ(max)  ≈ 490 to λ(max)  ≈ 476 nm. However, the incidence of blue-shifted light emission or the presence of accessory fluorescent proteins in bacteria of the genus Vibrio has never been reported. From our spectral analysis of light emitted by 16 luminous strains of the genus Vibrio, it was revealed that most strains of Vibrio azureus emit a blue-shifted light with a peak at approximately 472 nm, whereas other Vibrio strains emit light with a peak at around 482 nm. Therefore, we investigated the mechanism underlying this blue shift in V. azureus NBRC 104587(T) . Here, we describe the blue-shifted light emission spectra and the isolation of a blue fluorescent protein. Intracellular protein analyses showed that this strain had a blue fluorescent protein (that we termed VA-BFP), the fluorescent spectrum of which was almost identical to that of the in vivo light emission spectrum of the strain. This result strongly suggested that VA-BFP was responsible for the blue-shifted light emission of V. azureus.

  5. The relevance of analogue studies for understanding obsessions and compulsions.

    PubMed

    Abramowitz, Jonathan S; Fabricant, Laura E; Taylor, Steven; Deacon, Brett J; McKay, Dean; Storch, Eric A

    2014-04-01

    Analogue samples are often used to study obsessive-compulsive (OC) symptoms and related phenomena. This approach is based on the hypothesis that results derived from such samples are relevant to understanding OC symptoms in individuals with a diagnosis of obsessive-compulsive disorder (OCD). Two decades ago, Gibbs (1996) reviewed the available literature and found initial support for this hypothesis. Since then there have been many important advances addressing this issue. The purpose of the present review was to synthesize various lines of research examining the assumptions of using analogue samples to draw inferences about people with OCD. We reviewed research on the prevalence of OC symptoms in non-clinical populations, the dimensional (vs. categorical) nature of these symptoms, phenomenology, etiology, and studies on developmental and maintenance factors in clinical and analogue samples. We also considered the relevance of analogue samples in OCD treatment research. The available evidence suggests research with analogue samples is highly relevant for understanding OC symptoms. Guidelines for the appropriate use of analogue designs and samples are suggested.

  6. Cladribine Analogues via O6-(Benzotriazolyl) Derivatives of Guanine Nucleosides

    PubMed Central

    Satishkumar, Sakilam; Vuram, Prasanna K.; Relangi, Siva Subrahmanyam; Gurram, Venkateshwarlu; Zhou, Hong; Kreitman, Robert J.; Montemayor, Michelle M. Martínez; Yang, Lijia; Kaliyaperumal, Muralidharan; Sharma, Somesh; Pottabathini, Narender; Lakshman, Mahesh K.

    2016-01-01

    Cladribine, 2-chloro-2′-deoxyadenosine, is a highly efficacious clinically used nucleoside for the treatment of hairy cell leukemia. It is also being evaluated against other lymphoid malignancies and has been a molecule of interest for well over half a century. In continuation of our interest on the amide bond-activation in purine nucleosides via the use of (benzotriazol-1yl-oxy)tris(dimethylamino)phosphonium hexafluorophosphate, we have evaluated the use of O6-(benzotriazol-1-yl)-2′-deoxyguanosine as a potential precursor to cladribine and its analogues. These compounds, after appropriate deprotection, were assessed for their biological activities and the data are presented herein. Against hairy cell leukemia (HCL), T-cell lymphoma (TCL), and chronic lymphocytic leukemia (CLL) cladribine was the most active against all. The bromo analogue of cladribine showed comparable activity to the ribose analogue of cladribine against HCL, but was more active against TCL and CLL. The bromo ribo analogue of cladribine possessed activity, but was least active among the C6-NH2-containing compounds. Substitution with alkyl groups at the exocyclic amino group appears detrimental to activity, and only the C6 piperidinyl cladribine analogue demonstrated any activity. Against adenocarcinoma MDA-MB-231 cells, only cladribine and its ribose analogue were most active. PMID:26556315

  7. Analogue gravitational phenomena in Bose-Einstein condensates

    NASA Astrophysics Data System (ADS)

    Finazzi, Stefano

    2012-08-01

    Analogue gravity is based on the simple observation that perturbations propagating in several physical systems can be described by a quantum field theory in a curved spacetime. While phenomena like Hawking radiation are hardly detectable in astrophysical black holes, these effects may be experimentally tested in analogue systems. In this Thesis, focusing on Bose-Einstein condensates, we present our recent results about analogue models of gravity from three main perspectives: as laboratory tests of quantum field theory in curved spacetime, for the techniques that they provide to address various issues in general relativity, and as toy models of quantum gravity. The robustness of Hawking-like particle creation is investigated in flows with a single black hole horizon. Furthermore, we find that condensates with two (white and black) horizons develop a dynamical instability known in general relativity as black hole laser effect. Using techniques borrowed from analogue gravity, we also show that warp drives, which are general relativistic spacetimes allowing faster-than-light travel, are unstable. Finally, the cosmological constant issue is investigated from an analogue gravity perspective and relativistic Bose-Einstein condensates are proposed as new analogue systems with novel interesting properties.

  8. Cladribine Analogues via O⁶-(Benzotriazolyl) Derivatives of Guanine Nucleosides.

    PubMed

    Satishkumar, Sakilam; Vuram, Prasanna K; Relangi, Siva Subrahmanyam; Gurram, Venkateshwarlu; Zhou, Hong; Kreitman, Robert J; Montemayor, Michelle M Martínez; Yang, Lijia; Kaliyaperumal, Muralidharan; Sharma, Somesh; Pottabathini, Narender; Lakshman, Mahesh K

    2015-10-09

    Cladribine, 2-chloro-2'-deoxyadenosine, is a highly efficacious, clinically used nucleoside for the treatment of hairy cell leukemia. It is also being evaluated against other lymphoid malignancies and has been a molecule of interest for well over half a century. In continuation of our interest in the amide bond-activation in purine nucleosides via the use of (benzotriazol-1yl-oxy)tris(dimethylamino)phosphonium hexafluorophosphate, we have evaluated the use of O⁶-(benzotriazol-1-yl)-2'-deoxyguanosine as a potential precursor to cladribine and its analogues. These compounds, after appropriate deprotection, were assessed for their biological activities, and the data are presented herein. Against hairy cell leukemia (HCL), T-cell lymphoma (TCL) and chronic lymphocytic leukemia (CLL), cladribine was the most active against all. The bromo analogue of cladribine showed comparable activity to the ribose analogue of cladribine against HCL, but was more active against TCL and CLL. The bromo ribose analogue of cladribine showed activity, but was the least active among the C6-NH₂-containing compounds. Substitution with alkyl groups at the exocyclic amino group appears detrimental to activity, and only the C6 piperidinyl cladribine analogue demonstrated any activity. Against adenocarcinoma MDA-MB-231 cells, cladribine and its ribose analogue were most active.

  9. Molecular Biodynamers: Dynamic Covalent Analogues of Biopolymers.

    PubMed

    Liu, Yun; Lehn, Jean-Marie; Hirsch, Anna K H

    2017-02-21

    Constitutional dynamic chemistry (CDC) features the use of reversible linkages at both molecular and supramolecular levels, including reversible covalent bonds (dynamic covalent chemistry, DCC) and noncovalent interactions (dynamic noncovalent chemistry, DNCC). Due to its inherent reversibility and stimuli-responsiveness, CDC has been widely utilized as a powerful tool for the screening of bioactive compounds, the exploitation of receptors or substrates driven by molecular recognition, and the fabrication of constitutionally dynamic materials. Implementation of CDC in biopolymer science leads to the generation of constitutionally dynamic analogues of biopolymers, biodynamers, at the molecular level (molecular biodynamers) through DCC or at the supramolecular level (supramolecular biodynamers) via DNCC. Therefore, biodynamers are prepared by reversible covalent polymerization or noncovalent polyassociation of biorelevant monomers. In particular, molecular biodynamers, biodynamers of the covalent type whose monomeric units are connected by reversible covalent bonds, are generated by reversible polymerization of bio-based monomers and can be seen as a combination of biopolymers with DCC. Owing to the reversible covalent bonds used in DCC, molecular biodynamers can undergo continuous and spontaneous constitutional modifications via incorporation/decorporation and exchange of biorelevant monomers in response to internal or external stimuli. As a result, they behave as adaptive materials with novel properties, such as self-healing, stimuli-responsiveness, and tunable mechanical and optical character. More specifically, molecular biodynamers combine the biorelevant characters (e.g., biocompatibility, biodegradability, biofunctionality) of bioactive monomers with the dynamic features of reversible covalent bonds (e.g., changeable, tunable, controllable, self-healing, and stimuli-responsive capacities), to realize synergistic properties in one system. In addition, molecular

  10. Molecular Biodynamers: Dynamic Covalent Analogues of Biopolymers

    PubMed Central

    2017-01-01

    Conspectus Constitutional dynamic chemistry (CDC) features the use of reversible linkages at both molecular and supramolecular levels, including reversible covalent bonds (dynamic covalent chemistry, DCC) and noncovalent interactions (dynamic noncovalent chemistry, DNCC). Due to its inherent reversibility and stimuli-responsiveness, CDC has been widely utilized as a powerful tool for the screening of bioactive compounds, the exploitation of receptors or substrates driven by molecular recognition, and the fabrication of constitutionally dynamic materials. Implementation of CDC in biopolymer science leads to the generation of constitutionally dynamic analogues of biopolymers, biodynamers, at the molecular level (molecular biodynamers) through DCC or at the supramolecular level (supramolecular biodynamers) via DNCC. Therefore, biodynamers are prepared by reversible covalent polymerization or noncovalent polyassociation of biorelevant monomers. In particular, molecular biodynamers, biodynamers of the covalent type whose monomeric units are connected by reversible covalent bonds, are generated by reversible polymerization of bio-based monomers and can be seen as a combination of biopolymers with DCC. Owing to the reversible covalent bonds used in DCC, molecular biodynamers can undergo continuous and spontaneous constitutional modifications via incorporation/decorporation and exchange of biorelevant monomers in response to internal or external stimuli. As a result, they behave as adaptive materials with novel properties, such as self-healing, stimuli-responsiveness, and tunable mechanical and optical character. More specifically, molecular biodynamers combine the biorelevant characters (e.g., biocompatibility, biodegradability, biofunctionality) of bioactive monomers with the dynamic features of reversible covalent bonds (e.g., changeable, tunable, controllable, self-healing, and stimuli-responsive capacities), to realize synergistic properties in one system. In addition

  11. Habitability & Astrobiology Research in Mars Terrestrial Analogues

    NASA Astrophysics Data System (ADS)

    Foing, Bernard

    2014-05-01

    We performed a series of field research campaigns (ILEWG EuroMoonMars) in the extreme Utah desert relevant to Mars environments, and in order to help in the interpretation of Mars missions measurements from orbit (MEX, MRO) or from the surface (MER, MSL), or Moon geochemistry (SMART-1, LRO). We shall give an update on the sample analysis in the context of habitability and astrobiology. Methods & Results: In the frame of ILEWG EuroMoonMars campaigns (2009 to 2013) we deployed at Mars Desert Research station, near Hanksville Utah, a suite of instruments and techniques [A, 1, 2, 9-11] including sample collection, context imaging from remote to local and microscale, drilling, spectrometers and life sensors. We analyzed how geological and geochemical evolution affected local parameters (mineralogy, organics content, environment variations) and the habitability and signature of organics and biota. Among the important findings are the diversity in the composition of soil samples even when collected in close proximity, the low abundances of detectable PAHs and amino acids and the presence of biota of all three domains of life with significant heterogeneity. An extraordinary variety of putative extremophiles was observed [3,4,9]. A dominant factor seems to be soil porosity and lower clay-sized particle content [6-8]. A protocol was developed for sterile sampling, contamination issues, and the diagnostics of biodiversity via PCR and DGGE analysis in soils and rocks samples [10, 11]. We compare the 2009 campaign results [1-9] to new measurements from 2010-2013 campaigns [10-12] relevant to: comparison between remote sensing and in-situ measurements; the study of minerals; the detection of organics and signs of life. Keywords: field analogue research, astrobiology, habitability, life detection, Earth-Moon-Mars, organics References [A] Foing, Stoker & Ehrenfreund (Editors, 2011) "Astrobiology field Research in Moon/Mars Analogue Environments", Special Issue of International

  12. Design, Synthesis, and Evaluation of Genistein Analogues as Anti-Cancer Agents

    PubMed Central

    Xiong, Pahoua; Wang, Rubing; Zhang, Xiaojie; Torre, Eduardo DeLa; Leon, Francisco; Zhang, Qiang; Zheng, Shilong; Wang, Guangdi; Chen, Qiao-Hong

    2016-01-01

    Genistein is a bioactive isoflavone derived from soybeans. The tie-in between the intake of genistein and the decreased incidence of some solid tumors (including prostate cancer) has been demonstrated by epidemiological studies. The potential of genistein in treating prostate cancer has also been displayed by in vitro cell-based and in vivo animal experiments. Genistein has entered clinical trials for both chemoprevention and potential treatment of prostate cancer. Even though the low oral bioavailability has presented the major challenges to genistein’s further clinical development, chemical modulation of genistein holds the promise to generate potential anti-prostate cancer agents with enhanced potency and/or better pharmacokinetic profiles than genistein. As part of our ongoing project to develop natural products-based anti-prostate cancer agents, the current study was undertaken to synthesize eight genistein analogues for cytotoxic evaluation in three prostate cancer cell lines (PC-3, DU-145, LNCaP; both androgen-sensitive and androgen-refractory cell lines), as well as one aggressive cervical cancer cell line (HeLa). Eight genistein analogues have been successfully synthesized with Suzuki-Miyaura coupling reaction as a key step. Their in vitro anti-cancer potential was evaluated by trypan blue exclusion assay and WST-1 cell proliferation assay against a panel of four human cancer cell lines. The acquired data suggest i) that the C-5 and C-7 hydroxyl groups in genistein are very important for the cytotoxicity and anti-proliferative activity; and ii) that 1-alkyl-1H-pyrazol-4-yl and pyridine-3-yl might act as good bioisosteres for the 4'-hydroxyphenyl moiety in genistein. PMID:25991428

  13. Comparison of Alcian Blue, Trypan Blue, and Toluidine Blue for Visualization of the Primo Vascular System Floating in Lymph Ducts

    PubMed Central

    Kim, Da-Un; Han, Jae Won; Jung, Sharon Jiyoon; Lee, Seung Hwan; Cha, Richard; Chang, Byung-Soo; Soh, Kwang-Sup

    2015-01-01

    The primo vascular system (PVS), floating in lymph ducts, was too transparent to be observed by using a stereomicroscope. It was only detectable with the aid of staining dyes, for instance, Alcian blue, which was injected into the lymph nodes. Some dyes were absorbed preferentially by the PVS than the lymph wall. It remains a standing problem to know what dyes are absorbed better by the PVS than the lymph walls. Such information would be useful to unravel the biochemical properties of the PVS that are badly in need for obtaining large amount of PVS specimens. In the current work we tried two other familiar dyes which were used in PVS research before. We found that Trypan blue and toluidine blue did not visualize the PVS. Trypan blue was cleared by the natural washing. Toluidine blue did not stain the PVS, but it did leave stained spots in the lymph wall and its surrounding tissues, and it leaked out of the lymph wall to stain surrounding connective tissues. These completely different behaviors of the three dyes were found for the first time in the current work and provide valuable information to elucidate the mechanism through which some special dyes stained the PVS preferentially compared to the lymphatic wall. PMID:26379749

  14. Allergic contact dermatitis caused by the blue pigment VINAMON® Blue BX FW - a phthalocyanine blue in a vinyl glove.

    PubMed

    Weimann, Stefanie; Skudlik, Christoph; John, Swen Malte

    2010-10-01

    A 44-year-old metalworker suffered from severe hand eczema in spite of treatment with corticosteroid ointments. He had been using protective cotton gloves with blue PVC anti-slip dots on the finger tips. On clinical examination, the backs of both hands were erythematous and thickened while the finger tips showed vesicles. There was a positive patch test reaction to the blue PVC dots of an unworn cotton glove at 72, 96, 120 hours. To identify the causative chemicals, we carried out further patch tests using ingredients of the glove and cupric sulfate. The patient reacted to the blue dye VYNAMON(®) Blue BX FW (PB 15) at two concentrations - 10% at 72 and 96 hours, and 50% at 48 and 72 hours. This dye is a very strong and brilliant blue with red-copper tones and resistant to fire and weathering. The cupric-phthalocyanine complexes are used as pigments in cosmetics (e. g. CI 74160, 74180, 74260). To the best of our knowledge, no allergic reactions to this dye have been described, particularly not in gloves.

  15. Comparison of Alcian Blue, Trypan Blue, and Toluidine Blue for Visualization of the Primo Vascular System Floating in Lymph Ducts.

    PubMed

    Kim, Da-Un; Han, Jae Won; Jung, Sharon Jiyoon; Lee, Seung Hwan; Cha, Richard; Chang, Byung-Soo; Soh, Kwang-Sup

    2015-01-01

    The primo vascular system (PVS), floating in lymph ducts, was too transparent to be observed by using a stereomicroscope. It was only detectable with the aid of staining dyes, for instance, Alcian blue, which was injected into the lymph nodes. Some dyes were absorbed preferentially by the PVS than the lymph wall. It remains a standing problem to know what dyes are absorbed better by the PVS than the lymph walls. Such information would be useful to unravel the biochemical properties of the PVS that are badly in need for obtaining large amount of PVS specimens. In the current work we tried two other familiar dyes which were used in PVS research before. We found that Trypan blue and toluidine blue did not visualize the PVS. Trypan blue was cleared by the natural washing. Toluidine blue did not stain the PVS, but it did leave stained spots in the lymph wall and its surrounding tissues, and it leaked out of the lymph wall to stain surrounding connective tissues. These completely different behaviors of the three dyes were found for the first time in the current work and provide valuable information to elucidate the mechanism through which some special dyes stained the PVS preferentially compared to the lymphatic wall.

  16. Variations on the "Blue-Bottle" Demonstration Using Food Items That Contain FD&C Blue #1

    ERIC Educational Resources Information Center

    Staiger, Felicia A.; Peterson, Joshua P.; Campbell, Dean J.

    2015-01-01

    Erioglaucine dye (FD&C Blue #1) can be used instead of methylene blue in the classic "blue-bottle" demonstration. Food items containing FD&C Blue #1 and reducing species such as sugars can therefore be used at the heart of this demonstration, which simply requires the addition of strong base such as sodium hydroxide lye.

  17. Use of big data by Blue Cross and Blue Shield of North Carolina.

    PubMed

    Helm-Murtagh, Susan C

    2014-01-01

    The health care industry is grappling with the challenges of working with and analyzing large, complex, diverse data sets. Blue Cross and Blue Shield of North Carolina provides several promising examples of how big data can be used to reduce the cost of care, to predict and manage health risks, and to improve clinical outcomes.

  18. Structure of anthocyanin from the blue petals of Phacelia campanularia and its blue flower color development.

    PubMed

    Mori, Mihoko; Kondo, Tadao; Toki, Kenjiro; Yoshida, Kumi

    2006-03-01

    The dicaffeoyl anthocyanin, phacelianin, was isolated from blue petals of Phacelia campanularia. Its structure was determined to be 3-O-(6-O-(4'-O-(6-O-(4'-O-beta-d-glucopyranosyl-(E)-caffeoyl)-beta-d-glucopyranosyl)-(E)-caffeoyl)-beta-d-glucopyranosyl)-5-O-(6-O-malonyl-beta-d-glucopyranosyl)delphinidin. The CD of the blue petals of the phacelia showed a strong negative Cotton effect and that of the suspension of the colored protoplasts was the same, indicating that the chromophores of phacelianin may stack intermolecularly in an anti-clockwise stacking manner in the blue-colored vacuoles. In a weakly acidic aqueous solution, phacelianin displayed the same blue color and negative Cotton effect in CD as those of the petals. However, blue-black colored precipitates gradually formed without metal ions. A very small amount of Al(3+) or Fe(3+) may be required to stabilize the blue solution. Phacelianin may take both an inter- and intramolecular stacking form and shows the blue petal color by molecular association and the co-existence of a small amount of metal ions. We also isolated a major anthocyanin from the blue petals of Evolvulus pilosus and revised the structure identical to phacelianin.

  19. Identifying blues: an interview with lesbian blues musician and lyricist Gaye Adegbalola. Interview by Carmen Phelps.

    PubMed

    Adegbalola, Gaye

    2011-01-01

    In this interview, blues lyricist and musician Gaye Adegbalola shares with audiences how various political, social, and artistic influences have inspired her work since her activist years during the Black Arts Movement leading up to the present day. As a lesbian blues artist, Adegbalola's personal and artistic development implicates the often inextricable and intimate relationships between artistic production, political involvement, and individual fulfillment.

  20. 75 FR 65525 - Anthem Blue Cross Blue Shield, Claim Management Services, Inc. Operations, a Division of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-25

    ... Management Services, Inc. Operations, a Division of Wellpoint, Inc., Green Bay, Wisconsin (the subject firm... Employment and Training Administration Anthem Blue Cross Blue Shield, Claim Management Services, Inc. Operations, a Division of Wellpoint, Inc., Green Bay, WI; Notice of Negative Determination...

  1. Blue cotton, Blue Rayon and Blue Chitin in the analysis of heterocyclic aromatic amines--a review.

    PubMed

    Skog, Kerstin

    2004-03-25

    Heterocyclic amines (HCAs) are a group of compounds formed when protein-rich foods, such as meat or fish, are prepared under normal cooking conditions, such as frying, grilling, or broiling. To evaluate and estimate the risks associated with HCAs contained in the diet, it is important to determine the levels in cooked foods, and the levels of HCAs and metabolites in the body. HCAs are normally found at low amounts in a complex matrix, which necessitates a good purification method and a sensitive detection system. The objective of this review was to briefly present the current knowledge on the use of Blue Cotton, Blue Rayon and Blue Chitin in the analysis of HCAs.

  2. Imidazole-assisted catalysis of luminescence reaction in blue fluorescent protein from the photoprotein aequorin

    SciTech Connect

    Inouye, Satoshi . E-mail: sinouye@chisso.co.jp; Sasaki, Satoko

    2007-03-16

    Blue fluorescent protein from the calcium-binding photoprotein aequorin (BFP-aq) is a dissociable complex of Ca{sup 2+}-bound apoaequorin and coelenteramide, and is identified as a luciferase that catalyzes the oxidation of coelenterazine by molecular oxygen to emit light. Based on the chemical luminescence of coelenterazine oxidation by an acid-base mechanism, we found that the luminescence activity of BFP-aq was stimulated by imidazole at concentrations of 30-300 mM with coelenterazine and its analogues. The kinetic analyses indicate that imidazole has no effect on the binding affinity of coelenterazine to BFP-aq and may act as a catalytic base, accepting a proton from the -NH- group of coelenterazine and stimulating luminescence activity.

  3. Triboelectric Nanogenerators for Blue Energy Harvesting.

    PubMed

    Khan, Usman; Kim, Sang-Woo

    2016-07-26

    Blue energy in the form of ocean waves offers an enormous energy resource. However, it has yet to be fully exploited in order to make it available for the use of mankind. Blue energy harvesting is a challenging task as the kinetic energy from ocean waves is irregular in amplitude and is at low frequencies. Though electromagnetic generators (EMGs) are well-known for harvesting mechanical kinetic energies, they have a crucial limitation for blue energy conversion. Indeed, the output voltage of EMGs can be impractically low at the low frequencies of ocean waves. In contrast, triboelectric nanogenerators (TENGs) are highly suitable for blue energy harvesting as they can effectively harvest mechanical energies from low frequencies (<1 Hz) to relatively high frequencies (∼kHz) and are also low-cost, lightweight, and easy to fabricate. Several important steps have been taken by Wang's group to develop TENG technology for blue energy harvesting. In this Perspective, we describe some of the recent progress and also address concerns related to durable packaging of TENGs in consideration of harsh marine environments and power management for an efficient power transfer and distribution for commercial applications.

  4. Terrestrial research in Mars analogue environments

    NASA Astrophysics Data System (ADS)

    Osipov, G.

    Fatty acids (FA) content was measured by GC-MS SIM technique in Sulfide ores of present day (Mid-Atlantic Ridge and others) and ancient (Ural Paleocene, Russia) black smokers; Early Proterozoic kerites of Volyn; Siberian, Canadian and Antarctic permafrosts and also in rocks of East-European platform Achaean crystalline basement. Analysis was shown presence those and only those fatty acids which are specific to microorganisms. FA with 12 up 19 of carbon atoms are thought to be a bacterial biomass sign. 3-Hydroxy fatty acids also found in samples and are strong specific markers of gram-negative bacteria. Cultivation yield living bacteria in some cases. The East-European platform Achaean crystalline basement rocks opened by Vorotilov Deep Well (VDW) drilled through Puchezh-Katunski impact structure were studied within depths 2575 - 2805 m. 34 microbial lipid markers were detected by GC-MS and 22 species were identified. Bacteria of g. Bacillus reached 6,8 % in subsurface communities. However, members of gg. Clostridium (37,1 - 33,2 %) and Rhodococcus (27,6 - 33,7 %) were absolute dominants within studied depth interval. Some lipid patterns of kerite samples could be assessed to definite genera or, in special cases, to species of contemporary microorganisms. For instance, 2-hydroxylauric acid is specific to Pseudomonas putida group or Acinetobacter spp., and hydroxymyristic together with hydroxypalmitic are specific to P.cepacea and cyanobacteria. 3-hydroxystearic acid was known as component of Acetobacter diazothrophycus and Gloebacter violaceous cyanobacterium. 10-hydroxystearic acid associated with Nocardia spp., which oxidizes oleic acid in organic substrates. 10-methylhexadecanoic (10Me16) acid together with 10Me14, 10Me15 and 10Me17 analogues are markers of actinomycetes. Significant part of Black Smokers organic matter is probably biogenic. Fatty acid features strongly assigns it to bacterial, microeucariotic and planta cells. Par example 3-hydroxy acids are

  5. Bump in the blue axion isocurvature spectrum

    NASA Astrophysics Data System (ADS)

    Chung, Daniel J. H.; Upadhye, Amol

    2017-01-01

    Blue axion isocurvature perturbations are both theoretically well motivated and interesting from a detectability perspective. These power spectra generically have a break from the blue region to a flat region. Previous investigations of the power spectra were analytic, which left a gap in the predicted spectrum in the break region due to the nonapplicability of the used analytic techniques. We therefore compute the isocurvature spectrum numerically for an explicit supersymmetric axion model. We find a bump that enhances the isocurvature signal for this class of scenarios. A fitting function of three parameters is constructed that fits the spectrum well for the particular axion model we study. This fitting function should be useful for blue isocurvature signal hunting in data and making experimental sensitivity forecasts.

  6. Review of Insulin and its Analogues in Diabetes Mellitus

    PubMed Central

    Mane, Krishnappa; Chaluvaraju, KC; Niranjan, MS; Zaranappa, TR; Manjuthej, TR

    2012-01-01

    Diabetes is a metabolic disorder where in human body does not produce or properly uses insulin, a hormone that is required to convert sugar, starches and other food into energy. Diabetes finally leads to more complications and to prevent these complications insulin and its analogues are used. After more than half a century of treating diabetics with animal insulin’s, recombinant DNA technologies and advanced protein chemistry made human insulin preparations available in the early 1980s. As the next step, over the last decade, insulin analogues were constructed by changing the structure of the native protein with the goal of improving the therapeutic properties of it, because the pharmacokinetic characteristics of rapid, intermediate and long-acting preparations of human insulin make it almost impossible to achieve sustained normoglycemia. The first clinically available insulin analogue, lispro, confirmed the hopes by showing that improved glycaemic control can be achieved without an increase in hypoglycaemic events. Two new insulin analogues, insulin glargine and insulin aspart, have recently been approved for clinical use in the United States and several other analogues are being intensively tested. PMID:24826038

  7. Theoretical study on absorption and emission spectra of adenine analogues.

    PubMed

    Liu, Hongxia; Song, Qixia; Yang, Yan; Li, Yan; Wang, Haijun

    2014-04-01

    Fluorescent nucleoside analogues have attracted much attention in studying the structure and dynamics of nucleic acids in recent years. In the present work, we use theoretical calculations to investigate the structural and optical properties of four adenine analogues (termed as A1, A2, A3, and A4), and also consider the effects of aqueous solution and base pairing. The results show that the fluorescent adenine analogues can pair with thymine to form stable H-bonded WC base pairs. The excited geometries of both adenine analogues and WC base pairs are similar to the ground geometries. The absorption and emission maxima of adenine analogues are greatly red shifted compared with nature adenine, the oscillator strengths of A1 and A2 are stronger than A3 and A4 in both absorption and emission spectra. The calculated low-energy peaks in the absorption spectra are in good agreement with the experimental data. In general, the aqueous solution and base pairing can slightly red-shift both the absorption and emission maxima, and can increase the oscillator strengths of absorption spectra, but significantly decrease the oscillator strengths of A3 in emission spectra.

  8. Blue light inhibits proliferation of melanoma cells

    NASA Astrophysics Data System (ADS)

    Becker, Anja; Distler, Elisabeth; Klapczynski, Anna; Arpino, Fabiola; Kuch, Natalia; Simon-Keller, Katja; Sticht, Carsten; van Abeelen, Frank A.; Gretz, Norbert; Oversluizen, Gerrit

    2016-03-01

    Photobiomodulation with blue light is used for several treatment paradigms such as neonatal jaundice, psoriasis and back pain. However, little is known about possible side effects concerning melanoma cells in the skin. The aim of this study was to assess the safety of blue LED irradiation with respect to proliferation of melanoma cells. For that purpose we used the human malignant melanoma cell line SK-MEL28. Cell proliferation was decreased in blue light irradiated cells where the effect size depended on light irradiation dosage. Furthermore, with a repeated irradiation of the melanoma cells on two consecutive days the effect could be intensified. Fluorescence-activated cell sorting with Annexin V and Propidium iodide labeling did not show a higher number of dead cells after blue light irradiation compared to non-irradiated cells. Gene expression analysis revealed down-regulated genes in pathways connected to anti-inflammatory response, like B cell signaling and phagosome. Most prominent pathways with up-regulation of genes were cytochrome P450, steroid hormone biosynthesis. Furthermore, even though cells showed a decrease in proliferation, genes connected to the cell cycle were up-regulated after 24h. This result is concordant with XTT test 48h after irradiation, where irradiated cells showed the same proliferation as the no light negative control. In summary, proliferation of melanoma cells can be decreased using blue light irradiation. Nevertheless, the gene expression analysis has to be further evaluated and more studies, such as in-vivo experiments, are warranted to further assess the safety of blue light treatment.

  9. Change in NO2 reveals Parade Blue is cleaner than APEC Blue

    NASA Astrophysics Data System (ADS)

    Liu, Haoran; Liu, Cheng; Xie, Zhouqing; Xie, Pinhua; Xing, Chengzhi; Xu, Jin; Liu, Jianguo

    2016-04-01

    The spectacular Parade Blue (blue sky), and APEC Blue (blue sky) were renowned worldwide caused by the limiting discharge policy of the Chinese government. For evaluating the reduction of these two events, we analyzed the variation of NO2 columns Beijing by looking at a long-term monitoring using Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) and the Ozone Monitoring Instrument (OMI) satellite observations from August 2014 to November 2015, covering Grand Military Parade (GMP, September 2015) and APEC (November 2014) period. We found that the NO2 columns abruptly decreased both GMP and APEC. However, change in the MAX-DOAS and the OMI NO2 during GMP was larger than during APEC via comparison with the same period in 2014, indicating Parade Blue is cleaner than APEC Blue. The spatial distribution of NO2 and backward trajectories together with meterological parameters suggested that GMP Blue may be due to the regional significant decreasing discharge in peripheral cities. No weekend effect during GMP further confirmed the role of controlling discharge. This study provides direct evidence that it is possible to clean air in China.

  10. New rubrolide analogues as inhibitors of photosynthesis light reactions.

    PubMed

    Varejão, Jodieh O S; Barbosa, Luiz C A; Ramos, Gabriela Álvarez; Varejão, Eduardo V V; King-Díaz, Beatriz; Lotina-Hennsen, Blas

    2015-04-01

    Natural products called rubrolides have been investigated as a model for the development of new herbicides that act on the photosynthesis apparatus. This study comprises a comprehensive analysis of the photosynthesis inhibitory ability of 27 new structurally diverse rubrolide analogues. In general, the results revealed that the compounds exhibited efficient inhibition of the photosynthetic process, but in some cases low water solubility may be a limiting factor. To elucidate their mode of action, the effects of the compounds on PSII and PSI, as well as their partial reaction on chloroplasts and the chlorophyll a fluorescence transients were measured. Our results showed that some of the most active rubrolide analogues act as a Hill reaction inhibitors at the QB level by interacting with the D1 protein at the reducing side of PSII. All of the active analogues follow Tice's rule of 5, which indicates that these compounds present physicochemical properties suitable for herbicides.

  11. Analogue peptides for the immunotherapy of human acute myeloid leukemia.

    PubMed

    Hofmann, Susanne; Mead, Andrew; Malinovskis, Aleksandrs; Hardwick, Nicola R; Guinn, Barbara-Ann

    2015-11-01

    The use of peptide vaccines, enhanced by adjuvants, has shown some efficacy in clinical trials. However, responses are often short-lived and rarely induce notable memory responses. The reason is that self-antigens have already been presented to the immune system as the tumor develops, leading to tolerance or some degree of host tumor cell destruction. To try to break tolerance against self-antigens, one of the methods employed has been to modify peptides at the anchor residues to enhance their ability to bind major histocompatibility complex molecules, extending their exposure to the T-cell receptor. These modified or analogue peptides have been investigated as stimulators of the immune system in patients with different cancers with variable but sometimes notable success. In this review we describe the background and recent developments in the use of analogue peptides for the immunotherapy of acute myeloid leukemia describing knowledge useful for the application of analogue peptide treatments for other malignancies.

  12. Synthesis and antioxidant activity of a procyanidin B3 analogue.

    PubMed

    Mizuno, Mirei; Nakanishi, Ikuo; Matsubayashi, Satoko; Imai, Kohei; Arai, Takuya; Matsumoto, Ken-Ichiro; Fukuhara, Kiyoshi

    2017-02-15

    Proanthocyanidin, an oligomer of catechin, is a natural antioxidant and a potent inhibitor of lectin-like oxidized LDL receptor-1, which is involved in the pathogenesis of arteriosclerosis. We synthesized proanthocyanidin analogue 1, in which the geometry of one catechin molecule in procyanidin B3, a dimer of (+)-catechin, is constrained to be planar. The antioxidant activities of the compounds were evaluated in terms of their capacities to scavenge galvinoxyl radicals, and results demonstrate that while procyanidin was 3.8 times more potent than (+)-catechin, the radical scavenging activity of proanthocyanidin analogue 1 was further increased to 1.9 times that of procyanidin B3. This newly designed proanthocyanidin analogue 1 may be a promising lead compound for the treatment of arteriosclerosis and related cerebrovascular diseases.

  13. Analogue modelling of syntectonic leucosomes in migmatitic schists

    NASA Astrophysics Data System (ADS)

    Druguet, Elena; Carreras, Jordi

    2006-10-01

    Migmatites from the Cap de Creus tectonometamorphic belt display a wide variety of structures, from those formed when the leucosomes were melt-bearing, to those developed during solid-state deformation. The observed field structures have been modelled by means of analogue experiments. The materials used in the models are layered plasticine as a schist analogue, and chocolate as analogue of the crystallizing leucosome. A model for the development of syntectonic migmatites is proposed in which initial melt-bearing patches, preferentially formed within fertile pelitic layers, progressively evolve towards lens-shaped veins. Furthermore, heterogeneous deformation of anisotropic metasediments facilitates formation of extensional sites for further melt accumulation and transport. Melt crystallization implies a rapid increase in effective viscosity of leucosomes producing a reversal in competence contrast with respect to the enclosing schists. During the whole process, deformation localizes around crystallizing veins, giving rise to different and contrasting structures for melt-bearing and for solid-state stages.

  14. Design of novel CSA analogues as potential safeners and fungicides.

    PubMed

    Zheng, Yang; Liu, Bin; Gou, Zhaopin; Li, Yao; Zhang, Xiao; Wang, Yanqing; Yu, Shujing; Li, Yonghong; Sun, Dequn

    2015-02-15

    Study of safeners has been seldom reported in literature. In this work, a series of novel acylsulfamoylbenzamide analogues was designed and synthesized with newly developed safener cyprosulfamide (CSA) as the leading compound. The activity assay against the herbicide thiencarbazone-methyl (TCM) on maize revealed that fifteen compounds showed better protective effect than CSA on the fresh weight of aerial parts, twelve compounds exhibited better activity on the dry weight of aerial parts. Remarkably, two compounds (6Ih, 7II) had protective effect on the four aspects of TCM treated maize. Further antifungal assay showed their excellent activity against Physollospora piricola. The structure-activity relationships of CSA analogues as safeners and fungicides were discussed and it might be valuable for further molecular modification of new CSA analogues.

  15. Conception, synthesis, and biological evaluation of original discodermolide analogues.

    PubMed

    de Lemos, Elsa; Agouridas, Evangelos; Sorin, Geoffroy; Guerreiro, Antonio; Commerçon, Alain; Pancrazi, Ange; Betzer, Jean-François; Lannou, Marie-Isabelle; Ardisson, Janick

    2011-08-29

    Due to its intriguing biological activity profile and potential chemotherapeutic application discodermolide (DDM) proved to be an attractive target. Therefore, notable efforts have been carried out directed toward its total synthesis and toward the production and evaluation of synthetic analogues. Recently, we achieved the total synthesis of DDM. At the present, guided by the knowledge gained during our DDM total synthesis and by the requirement of keeping the bioactive "U" shape conformation, we report the convergent preparation of five original analogues. Three types of changes were realized through modification of the terminal (Z)-diene moiety, of the methyl group at the C14-position, and the lactone region. All analogues were active in the nanomolar range and two of them turned out to be equipotent to DDM.

  16. Migrastatin analogues target fascin to block tumour metastasis.

    PubMed

    Chen, Lin; Yang, Shengyu; Jakoncic, Jean; Zhang, J Jillian; Huang, Xin-Yun

    2010-04-15

    Tumour metastasis is the primary cause of death of cancer patients. Development of new therapeutics preventing tumour metastasis is urgently needed. Migrastatin is a natural product secreted by Streptomyces, and synthesized migrastatin analogues such as macroketone are potent inhibitors of metastatic tumour cell migration, invasion and metastasis. Here we show that these migrastatin analogues target the actin-bundling protein fascin to inhibit its activity. X-ray crystal structural studies reveal that migrastatin analogues bind to one of the actin-binding sites on fascin. Our data demonstrate that actin cytoskeletal proteins such as fascin can be explored as new molecular targets for cancer treatment, in a similar manner to the microtubule protein tubulin.

  17. Largazole Analogues Embodying Radical Changes in the Depsipeptide Ring: Development of a More Selective and Highly Potent Analogue.

    PubMed

    Almaliti, Jehad; Al-Hamashi, Ayad A; Negmeldin, Ahmed T; Hanigan, Christin L; Perera, Lalith; Pflum, Mary Kay H; Casero, Robert A; Tillekeratne, L M Viranga

    2016-12-08

    A number of analogues of the marine-derived histone deacetylase inhibitor largazole incorporating major structural changes in the depsipeptide ring were synthesized. Replacing the thiazole-thiazoline fragment of largazole with a bipyridine group gave analogue 7 with potent cell growth inhibitory activity and an activity profile similar to that of largazole, suggesting that conformational change accompanying switching hybridization from sp(3) to sp(2) at C-7 is well tolerated. Analogue 7 was more class I selective compared to largazole, with at least 464-fold selectivity for class I HDAC proteins over class II HDAC6 compared to a 22-fold selectivity observed with largazole. To our knowledge 7 represents the first example of a potent and highly cytotoxic largazole analogue not containing a thiazoline ring. The elimination of a chiral center derived from the unnatural amino acid R-α-methylcysteine makes the molecule more amenable to chemical synthesis, and coupled with its increased class I selectivity, 7 could serve as a new lead compound for developing selective largazole analogues.

  18. Synthesis of daidzin analogues as potential agents for alcohol abuse.

    PubMed

    Gao, Guang-Yao; Li, Dian-Jun; Keung, Wing Ming

    2003-09-01

    Daidzin, the active principle of an herbal remedy for 'alcohol addiction', has been shown to reduce alcohol consumption in all laboratory animals tested to date. Correlation studies using structural analogues of daidzin suggests that it acts by raising the monoamine oxidase (MAO)/mitochondrial aldehyde dehydrogenase (ALDH-2) activity ratio (J. Med. Chem. 2000, 43, 4169). Structure-activity relationship (SAR) studies on the 7-O-substituted analogues of daidzin have revealed structural features important for ALDH-2 and MAO inhibition (J. Med. Chem. 2001, 44, 3320). We here evaluated effects of substitutions at 2, 5, 6, 8, 3' and 4' positions of daidzin on its potencies for ALDH-2 and MAO inhibition. Results show that analogues with 4'-substituents that are small, polar and with hydrogen bonding capacities are most potent ALDH-2 inhibitors, whereas those that are non-polar and with electron withdrawing capacities are potent MAO inhibitors. Analogues with a 5-OH group are less potent ALDH-2 inhibitors but are more potent MAO inhibitors. All the 2-, 6-, 8- and 3'-substituted analogues tested so far do not inhibit ALDH-2 and/or have decreased potencies for MAO inhibition. This, together with the results obtained from previous studies, suggests that a potent antidipsotropic analogue would be a 4',7-disubstituted isoflavone. The 4'-substituent should be small, polar, and with hydrogen bonding capacities such as, -OH and -NH(2); whereas the 7-substituent should be a straight-chain alkyl with a terminal polar function such as -(CH(2))(n)-OH with 2< or =n < or =6, -(CH(2))(n)-COOH with 5< or =n < or =10, or -(CH(2))(n)-NH(2) with n > or =4.

  19. The Object-analogue approach for probabilistic forecasting

    NASA Astrophysics Data System (ADS)

    Frediani, M. E.; Hopson, T. M.; Anagnostou, E. N.; Hacker, J.

    2015-12-01

    The object-analogue is a new method to estimate forecast uncertainty and to derive probabilistic predictions of gridded forecast fields over larger regions rather than point locations. The method has been developed for improving the forecast of 10-meter wind speed over the northeast US, and it can be extended to other forecast variables, vertical levels, and other regions. The object-analogue approach combines the analog post-processing technique (Hopson 2005; Hamill 2006; Delle Monache 2011) with the Method for Object-based Diagnostic Evaluation (MODE) for forecast verification (Davis et al 2006a, b). Originally, MODE is used to verify mainly precipitation forecasts using features of a forecast region represented by an object. The analog technique is used to reduce the NWP systematic and random errors of a gridded forecast field. In this study we use MODE-derived objects to characterize the wind fields forecasts into attributes such as object area, centroid location, and intensity percentiles, and apply the analogue concept to these objects. The object-analogue method uses a database of objects derived from reforecasts and their respective reanalysis. Given a real-time forecast field, it searches the database and selects the top-ranked objects with the most similar set of attributes using the MODE fuzzy logic algorithm for object matching. The attribute probabilities obtained with the set of selected object-analogues are used to derive a multi-layer probabilistic prediction. The attribute probabilities are combined into three uncertainty layers that address the main concerns of most applications: location, area, and magnitude. The multi-layer uncertainty can be weighted and combined or used independently in such that it provides a more accurate prediction, adjusted according to the application interest. In this study we present preliminary results of the object-analogue method. Using a database with one hundred storms we perform a leave-one-out cross-validation to

  20. On slow light as a black hole analogue

    NASA Astrophysics Data System (ADS)

    Unruh, W. G.; Schützhold, R.

    2003-07-01

    Although slow light (electromagnetically induced transparency) would seem an ideal medium in which to institute a “dumb hole” (black hole analogue), it suffers from a number of problems. We show that the high phase velocity in the slow light regime ensures that the system cannot be used as an analogue displaying Hawking radiation. Even though an appropriately designed slow-light setup may simulate classical features of black holes—such as horizon, mode mixing, “Bogoliubov” coefficients, etc.—it does not reproduce the related quantum effects.

  1. Naturally occurring crystalline phases: analogues for radioactive waste forms

    SciTech Connect

    Haaker, R.F.; Ewing, R.C.

    1981-01-01

    Naturally occurring mineral analogues to crystalline phases that are constituents of crystalline radioactive waste forms provide a basis for comparison by which the long-term stability of these phases may be estimated. The crystal structures and the crystal chemistry of the following natural analogues are presented: baddeleyite, hematite, nepheline; pollucite, scheelite;sodalite, spinel, apatite, monazite, uraninite, hollandite-priderite, perovskite, and zirconolite. For each phase in geochemistry, occurrence, alteration and radiation effects are described. A selected bibliography for each phase is included.

  2. Non-natural acetogenin analogues as potent Trypanosoma brucei inhibitors

    PubMed Central

    Florence, Gordon J.; Fraser, Andrew L.; Gould, Eoin R.; King, Elizabeth F.; Menzies, Stefanie K.; Morris, Joanne C.; Tulloch, Lindsay B.; Smith, Terry K.

    2015-01-01

    A series of novel bis-tetrahydropyran 1,4-triazole analogues based on the acetogenin framework display low micromolar trypanocidal activities towards both bloodstream and insect forms of Trypanosoma brucei, the causative agent of African sleeping sickness. A divergent synthetic strategy was adopted for the synthesis of the key tetrahydropyran intermediates to enable rapid access to diastereochemical variation either side of the 1,4-triazole core. The resulting diastereomeric analogues displayed varying degrees of trypanocidal activity and selectivity in structure activity relationship studies. PMID:25145275

  3. Retro-1 Analogues Differentially Affect Oligonucleotide Delivery and Toxin Trafficking.

    PubMed

    Yang, Bing; Ming, Xin; Abdelkafi, Hajer; Pons, Valerie; Michau, Aurelien; Gillet, Daniel; Cintrat, Jean-Christophe; Barbier, Julien; Juliano, Rudy

    2016-11-21

    Retro-1 is a small molecule that displays two important biological activities: First, it blocks the actions of certain toxins by altering their intracellular trafficking. Second, it enhances the activity of oligonucleotides by releasing them from entrapment in endosomes. This raises the question of whether the two actions involve the same cellular target. Herein we report the effects of several Retro-1 analogues on both toxins and oligonucleotides. We found analogues that affect toxins but not oligonucleotides and vice-versa, while Retro-1 is the only compound that affects both. This indicates that the molecular target(s) involved in the two processes are distinct.

  4. Synthesis and evaluation of heterocyclic analogues of bromoxynil.

    PubMed

    Cutulle, Matthew A; Armel, Gregory R; Brosnan, James T; Best, Michael D; Kopsell, Dean A; Bruce, Barry D; Bostic, Heidi E; Layton, Donovan S

    2014-01-15

    One attractive strategy to discover more active and/or crop-selective herbicides is to make structural changes to currently registered compounds. This strategy is especially appealing for those compounds with limited herbicide resistance and whose chemistry is accompanied with transgenic tools to enable herbicide tolerance in crop plants. Bromoxynil is a photosystem II (PSII) inhibitor registered for control of broadleaf weeds in several agronomic and specialty crops. Recently at the University of Tennessee-Knoxville several analogues of bromoxynil were synthesized including a previously synthesized pyridine (2,6-dibromo-5-hydroxypyridine-2-carbonitrile sodium salt), a novel pyrimidine (4,6-dibromo-5-hydroxypyrimidine-2-carbonitrile sodium salt), and a novel pyridine N-oxide (2,6-dibromo-1-oxidopyridin-1-ium-4-carbonitrile). These new analogues of bromoxynil were also evaluated for their herbicidal activity on soybean (Glycine max), cotton (Gossypium hirsutum), redroot pigweed (Amaranthus retroflexus), velvetleaf (Abutilon theophrasti), large crabgrass (Digitaria sanguinalis), and pitted morningglory ( Ipomoea lacunose ) when applied at 0.28 kg ha(-1). A second study was conducted on a glyphosate-resistant weed (Amaranthus palmeri) with the compounds being applied at 0.56 kg ha(-1). Although all compounds were believed to inhibit PSII by binding in the quinone binding pocket of D1, the pyridine and pyridine-N-oxide analogues were clearly more potent than bromoxynil on Amaranthus retroflexus. However, application of the pyrimidine herbicide resulted in the least injury to all species tested. These variations in efficacy were investigated using molecular docking simulations, which indicate that the pyridine analogue may form a stronger hydrogen bond in the pocket of the D1 protein than the original bromoxynil. A pyridine analogue was able to control the glyphosate-resistant Amaranthus palmeri with >80% efficacy. The pyridine analogues of bromoxynil showed potential

  5. Relationship between antimold activity and molecular structure of cinnamaldehyde analogues.

    PubMed

    Zhang, Yuanyuan; Li, Shujun; Kong, Xianchao

    2013-03-01

    A quantitative structure-activity relationship (QSAR) modeling of the antimold activity of cinnamaldehyde analogues against of Aspergillus niger and Paecilomyces variotii was presented. The molecular descriptors of cinnamaldehyde analogues were calculated by the CODESSA program, and these descriptors were selected by best multi-linear regression method (BMLR). Satisfactory multilinear regression models of Aspergillus niger and Paecilomyces variotii were obtained with R(2)=0.9099 and 0.9444, respectively. The models were also satisfactorily validated using internal validation and leave one out validation. The QSAR models provide the guidance for further synthetic work.

  6. Synthesis and antihistamine evaluations of novel loratadine analogues.

    PubMed

    Wang, Yue; Wang, Juan; Lin, Yan; Si-Ma, Li-Feng; Wang, Dong-hua; Chen, Li-Gong; Liu, Deng-Ke

    2011-08-01

    A series of loratadine analogues containing hydroxyl group and chiral center were synthesized. The effect of the synthesized compounds on the histamine-induced contractions of guinea-pig ileum muscles was studied. In addition, the in vivo asthma-relieving effect of the analogues in the histamine induced asthmatic reaction in guinea-pigs was determined. Most of the compounds exhibited definite H(1) antihistamine activity. The S-enantiomers, compounds 2, 4 and 8, are more potent than the R-enantiomers, compounds 1, 3 and 7. Compound 6 was the most active one among the eight synthesized compounds.

  7. Fluorescent diethylcarbamazine analogues: sites of accumulation in Brugia malayi.

    PubMed

    Junnila, Amy; Bohle, D Scott; Prichard, Roger; Perepichka, Inna; Spina, Carla

    2007-01-01

    New fluorescein and rhodamine B-labeled antifilarial drug DEC analogues for use in drug localization studies with confocal microscopy have been prepared by a high-yield three-step synthesis. The resulting beta-amine-substituted DEC analogue has a single ethyl substituent which is beta-aminated to accommodate the fluorophore of either fluorescein isothiocyananate or rhodamine B. Confocal microscopy is used to show that the drug accumulates in the adult filarial worms in the pharynx, esophagus, and near the nerve ring of all adults, as well as in the uteri and vulva and the testes of the females and males.

  8. Blue whales respond to anthropogenic noise.

    PubMed

    Melcón, Mariana L; Cummins, Amanda J; Kerosky, Sara M; Roche, Lauren K; Wiggins, Sean M; Hildebrand, John A

    2012-01-01

    Anthropogenic noise may significantly impact exposed marine mammals. This work studied the vocalization response of endangered blue whales to anthropogenic noise sources in the mid-frequency range using passive acoustic monitoring in the Southern California Bight. Blue whales were less likely to produce calls when mid-frequency active sonar was present. This reduction was more pronounced when the sonar source was closer to the animal, at higher sound levels. The animals were equally likely to stop calling at any time of day, showing no diel pattern in their sensitivity to sonar. Conversely, the likelihood of whales emitting calls increased when ship sounds were nearby. Whales did not show a differential response to ship noise as a function of the time of the day either. These results demonstrate that anthropogenic noise, even at frequencies well above the blue whales' sound production range, has a strong probability of eliciting changes in vocal behavior. The long-term implications of disruption in call production to blue whale foraging and other behaviors are currently not well understood.

  9. Avoiding the Negative: Blue Jeans Baseball

    ERIC Educational Resources Information Center

    Maggard, Bob

    1978-01-01

    Blue Jeans Baseball, for eight- to twelve-year old children, is based on the concept that everyone plays. No coaches are allowed; everyone bats once per inning; defensive players rotate positions. These and other rules reduce the emphasis on competition and increase the emphasis on skill development. (MJB)

  10. Bdellovibrios in Callinectus sapidus, the Blue Crab

    PubMed Central

    Kelley, Jacqueline I.; Williams, Henry N.

    1992-01-01

    Bdellovibrios were recovered from the gill tissue of all of 31 crabs sampled and from all samples of epibiota obtained from the ventral shell surface of 15 crabs. The results suggest that the blue crab is a reservoir for bdellovibrios. The association with crabs may be an important factor in the ecology of the bdellovibrios. PMID:16348706

  11. T's and Blues. Specialized Information Service.

    ERIC Educational Resources Information Center

    Do It Now Foundation, Phoenix, AZ.

    This compilation of journal articles provides basic information on abuse of Talwin, a mild prescription painkiller (T's), and Pyribenzamine, a nonprescription antihistimine (Blues). These two drugs, taken in combination, produce an effect similar to that produced by heroin. Stories from "Drug Survival News,""Emergency…

  12. Delta Blues Scholarship and Imperialist Nostalgia.

    ERIC Educational Resources Information Center

    Nye, William P.

    When Delta blues are considered to be "folk music," the genre is inextricably tied to the neocolonial, sharecropping system of cotton production characteristic of the Mississippi Delta region between the Civil War and World War II. "Imperialist nostalgia," then, arises in accounts which pay primary and positive tribute to blues…

  13. Geographical Study of American Blues Culture

    ERIC Educational Resources Information Center

    Strait, John B.

    2010-01-01

    Music is not often utilized in teaching geography, despite the fact that many scholars orient their research around analyzing both the historical and spatial dimensions of musical expression. This article reports on the use of a teaching module that utilizes blues culture as a lens to understand the geographical history of the United States. The…

  14. Blue LED irradiation to hydration of skin

    NASA Astrophysics Data System (ADS)

    Menezes, Priscila F. C.; Requena, Michelle B.; Lizarelli, Rosane F., Z.; Bagnato, Vanderlei S.

    2015-06-01

    Blue LED system irradiation shows many important properties on skin as: bacterial decontamination, degradation of endogenous skin chromophores and biostimulation. In this clinical study we prove that the blue light improves the skin hydration. In the literature none authors reports this biological property on skin. Then this study aims to discuss the role of blue light in the skin hydration. Twenty patients were selected to this study with age between 25-35 years old and phototype I, II and III. A defined area from forearm was pre determined (A = 4.0 cm2). The study was randomized in two treatment groups using one blue light device (power of 5.3mW and irradiance of 10.8mW/cm2). The first treatment group was irradiated with 3J/cm2 (277seconds) and the second with 6J/cm2 (555 seconds). The skin hydration evaluations were done using a corneometer. The measurements were collected in 7, 14, 21 and 30 days, during the treatment. Statistical test of ANOVA, Tukey and T-Student were applied considering 5% of significance. In conclusion, both doses were able to improve the skin hydration; however, 6J/cm2 has kept this hydration for 30 days.

  15. Visualising DNA in Classrooms Using Nile Blue

    ERIC Educational Resources Information Center

    Milne, Christine; Roche, Scott; McKay, David

    2008-01-01

    Giving students the opportunity to extract, manipulate and visualise DNA molecules enhances a constructivist approach to learning about modern techniques in biology and biotechnology Visualisation usually requires agarose gel electrophoresis and staining. In this article, we report on an alternative DNA stain, Nile Blue A, that may be used in the…

  16. [The dangers of blue light: True story!].

    PubMed

    Renard, G; Leid, J

    2016-05-01

    The dangers of the blue light are the object of numerous publications, for both the scientific community and the general public. The new prolific development of light sources emitting potentially toxic blue light (415-455nm) ranges from LED (Light Emitting Diodes) lamps for interior lighting to television screens, computers, digital tablets and smartphones using OLED (Organic Light Emitting Diode) or AMOLED (Active-Matrix Organic Light Emitting Diode) technology. First we will review some technical terms and the main characteristics of light perceived by the human eye. Then we will discuss scientific proof of the toxicity of blue light to the eye, which may cause cataract or macular degeneration. Analysis of the light spectra of several light sources, from natural light to LED lamps, will allow us to specify even better the dangers related to each light source. LED lamps, whether used as components for interior lighting or screens, are of concern if they are used for extended viewing times and at short distance. While we can protect ourselves from natural blue light by wearing colored glasses which filter out, on both front and back surfaces, the toxic wavelengths, it is more difficult to protect oneself from LED lamps in internal lighting, the use of which should be restricted to "white warmth" lamps (2700K). As far as OLED or AMOLED screens are concerned, the only effective protection consists of using them occasionally and only for a short period of time.

  17. Blue nano titania made in diffusion flames.

    PubMed

    Teleki, Alexandra; Pratsinis, Sotiris E

    2009-05-21

    Blue titanium suboxide nanoparticles (including Magneli phases) were formed directly without any post-processing or addition of dopants by combustion of titanium-tetra-isopropoxide (TTIP) vapor at atmospheric pressure. Particle size, phase composition, rutile and anatase crystal sizes as well as the blue coloration were controlled by rapid quenching of the flame with a critical flow nozzle placed at various heights above the burner. The particles showed a broad absorption in the near-infrared region and retained their blue color upon storage in ambient atmosphere. A high concentration of paramagnetic Ti3+ centres was found in the substoichiometric particles by electron paramagnetic resonance (EPR) spectroscopy. Furthermore particles with controlled band gap energy from 3.2 to 3.6 eV were made by controlling the burner-nozzle-distance from 10 to 1 cm, respectively. The color robustness and extent of suboxidation could be further enhanced by co-oxidation of TTIP with hexamethyldisiloxane in the flame resulting in SiO2-coated titanium suboxide particles. The process is cost-effective and green while the particles produced can replace traditional blue colored, cobalt-containing pigments.

  18. A Discography of the Real Blues

    ERIC Educational Resources Information Center

    Tudor, Dean

    1972-01-01

    A short account of the rise and decline of the Blues and a discussion of the artists who performed it is followed by an annotated bibliography of periodicals, books, records and tapes related to this form of Black" music. (184 references) (NH)

  19. Practices of Blue Ribbon Catholic Schools, 2001.

    ERIC Educational Resources Information Center

    Kealey, Robert J., Comp.

    For almost 20 years, the U.S. Department of Education has invited schools to seek the Blue Ribbon School Award. A large number of Catholic schools have received this award. For this publication, the Department of Elementary Schools Executive Committee requested principals of awarded schools to write a short article on an exemplary school program…

  20. Blue Whales Respond to Anthropogenic Noise

    PubMed Central

    Melcón, Mariana L.; Cummins, Amanda J.; Kerosky, Sara M.; Roche, Lauren K.; Wiggins, Sean M.; Hildebrand, John A.

    2012-01-01

    Anthropogenic noise may significantly impact exposed marine mammals. This work studied the vocalization response of endangered blue whales to anthropogenic noise sources in the mid-frequency range using passive acoustic monitoring in the Southern California Bight. Blue whales were less likely to produce calls when mid-frequency active sonar was present. This reduction was more pronounced when the sonar source was closer to the animal, at higher sound levels. The animals were equally likely to stop calling at any time of day, showing no diel pattern in their sensitivity to sonar. Conversely, the likelihood of whales emitting calls increased when ship sounds were nearby. Whales did not show a differential response to ship noise as a function of the time of the day either. These results demonstrate that anthropogenic noise, even at frequencies well above the blue whales' sound production range, has a strong probability of eliciting changes in vocal behavior. The long-term implications of disruption in call production to blue whale foraging and other behaviors are currently not well understood. PMID:22393434

  1. Heparin sensing: Blue-chip binding

    NASA Astrophysics Data System (ADS)

    Shriver, Zachary; Sasisekharan, Ram

    2013-08-01

    Heparin is an anionic polysaccharide that has tremendous clinical importance as an anticoagulant. Several dyes have been developed that can detect heparin, and the latest example -- named Mallard Blue -- has now been shown to have excellent sensing properties under biologically relevant conditions.

  2. Blue-hazard-free Candlelight OLED.

    PubMed

    Jou, Jwo-Huei; Singh, Meenu; Su, Yu-Ting; Liu, Shih-Hao; He, Zhe-Kai

    2017-03-19

    A candlelight-style organic light emitting diode (OLED) is a human-friendly type of lighting because it is blue-hazard-free and has a low correlated color temperature (CCT) illumination. The low CCT lighting is deprived of high-energy blue radiation, and it can be used for a longer duration before causing retinal damage. This work presents the comprehensive protocols for the fabrication of blue-hazard-free candlelight OLEDs. The emission spectrum of the OLED was characterized by the maximum exposure time limit of the retina and the melatonin suppression sensitivity. The devices can be fabricated using dry and wet processes. The dry-processed OLED resulted in a CCT of 1,940 K and exhibited a maximum retinal exposure limit of 1,287 s at a brightness of 500 lx. It showed 2.61% melatonin suppression sensitivity relative to 480 nm blue light. The wet-processed OLED, where the spin coating is used to deposit hole injection, hole transport, and emissive layers, making fabrication fast and economical, produced a CCT of 1,922 K and showed a maximum retinal exposure limit of 7,092 at a brightness of 500 lx. The achieved relative melatonin suppression sensitivity of 1.05% is 86% and 96% less than that of the light emitting diode (LED) and compact fluorescent lamp (CFL), respectively. Wet-processed blue-hazard-free candlelight OLED exhibited a power efficiency of 30 lm/W, which is 2 times that of the incandescent bulb and 300 times that of the candle.

  3. Chiral heteropoly blues and controllable switching of achiral polyoxometalate clusters.

    PubMed

    Wang, Yizhan; Li, Haolong; Wu, Che; Yang, Yang; Shi, Lei; Wu, Lixin

    2013-04-22

    Managing the blues: Chiral heteropoly blues of achiral polyoxometalate clusters were created through an intermolecular interaction with a chiral organic compound. Controllable chiroptical switching of the cluster complexes was possible through reversible photochromism of the polyoxometalates (see picture).

  4. Missions to Mars: Characterisation of Mars analogue rocks for the International Space Analogue Rockstore (ISAR)

    NASA Astrophysics Data System (ADS)

    Bost, Nicolas; Westall, Frances; Ramboz, Claire; Foucher, Frédéric; Pullan, Derek; Meunier, Alain; Petit, Sabine; Fleischer, Iris; Klingelhöfer, Göstar; Vago, Jorge L.

    2013-07-01

    Instruments for surface missions to extraterrestrial bodies should be cross-calibrated using a common suite of relevant materials. Such work is necessary to improve instrument performance and aids in the interpretation of in-situ measurements. At the CNRS campus in Orléans, the Observatoire des Sciences de l'Univers en région Centre (OSUC) has created a collection of well-characterised rocks and minerals for testing and calibrating instruments to be flown in space missions. The characteristics of the analogue materials are documented in an accompanying online database. In view of the recent and upcoming rover missions to Mars (NASA's 2011 Mars Science Laboratory (MSL) and ESA/Roscosmos' 2018 ExoMars), we are concentrating initially on materials of direct relevance to the red planet. The initial collection consists of 15 well-studied rock and mineral samples, including a variety of basalts (ultramafic, weathered, silicified, primitive), sediments (volcanic sands, chert, and a banded iron formation -BIF-), and the phyllosilicate nontronite (a clay). All the samples were characterised petrographically, petrologically, and geochemically using the types of analyses likely to be performed during in-situ missions, in particular ExoMars: hand specimen description; optical microscopy; mineralogical analysis by XRD, Raman and IR spectrometry; iron phase analysis by Mössbauer spectroscopy (MBS), elemental analysis by Energy-Dispersive X-ray spectroscopy (EDX), microprobe, Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) and Mass Spectrometry (ICP-MS); and reduced carbon analysis by Raman spectrometry.

  5. [Oxazaphosphorinane drugs. New analogues, metabolic studies, and therapeutic approaches].

    PubMed

    Misiura, Konrad

    2004-01-01

    Recent studies on oxazaphosphorinane drugs, with the main focus on those carried out in Poland, are briefly reviewed. Research leading to the introduction of the new antitumor drug (S)-(-)-bromofosfamide are presented. The utility of phosphorus nuclear magnetic resonance in studies of ifosfamide metabolism and an application of analogues of the final, active metabolite of this drug in gene therapy are shown.

  6. An Analysis of an Autoclitic Analogue in Pigeons

    ERIC Educational Resources Information Center

    Kuroda, Toshikazu; Lattal, Kennon A.; García-Penagos, Andrés

    2014-01-01

    Using a conditional discrimination procedure, pigeons were exposed to a nonverbal analogue of qualifying autoclitics such as "definitely" and "maybe." It has been suggested that these autoclitics are similar to tacts except that they are under the control of private discriminative stimuli. Instead of the conventional assumption…

  7. A Macroscopic Analogue of the Nuclear Pairing Potential

    ERIC Educational Resources Information Center

    Dunlap, Richard A.

    2013-01-01

    A macroscopic system involving permanent magnets is used as an analogue to nucleons in a nucleus to illustrate the significance of the pairing interaction. This illustrates that the view of the total nuclear energy based only on the nucleon occupancy of the energy levels can yield erroneous results and it is only when the pairing interaction is…

  8. Facile Synthesis of Natural Alkoxynaphthalene Analogues from Plant Alkoxybenzenes.

    PubMed

    Tsyganov, Dmitry V; Krayushkin, Mikhail M; Konyushkin, Leonid D; Strelenko, Yuri A; Semenova, Marina N; Semenov, Victor V

    2016-04-22

    Analogues of the bioactive natural alkoxynaphthalene pycnanthulignene D were synthesized by an efficient method. The starting plant allylalkoxybenzenes (1) are easily available from the plant essential oils of sassafras, dill, and parsley. The target 1-arylalkoxynaphthalenes (5) exhibited antiproliferative activity in a phenotypic sea urchin embryo assay.

  9. A Laboratory Analogue for the Study of Peer Sexual Harassment

    ERIC Educational Resources Information Center

    Mitchell, Damon; Hirschman, Richard; Angelone, D. J.; Lilly, Roy S.

    2004-01-01

    The purpose of this study was to develop a laboratory analogue for the study of peer sexual harassment, and to examine person and situational factors associated with male on female peer sexual harassment. One hundred twenty-two male participants were given the opportunity to tell jokes to a female confederate from a joke list that included…

  10. Interaction of tRNA with antitumor polyamine analogues.

    PubMed

    N'soukpoé-Kossi, C N; Ahmed Ouameur, A; Thomas, T; Thomas, T J; Tajmir-Riahi, H A

    2009-08-01

    We studied the interaction between tRNA and three polyamine analogues (1,11-diamino-4,8-diazaundecane.4HCl (333), 3,7,11,15-tetrazaheptadecane.4HCl (BE-333), and 3,7,11,15,19-pentazahenicosane.5HCl (BE-3333)) using FTIR, UV-visible, and CD spectroscopic methods. Spectroscopic evidence showed that polyamine analogues bound tRNA via guanine N7, adenine, uracil O2, and the backbone phosphate (PO2-) groups, while the most reactive sites for biogenic polyamines were guanine N7/O6, adenine N7, uracil O2, and sugar 2'-OH groups as well as the backbone phosphate group. The binding constants of polyamine analogue-tRNA recognition were lower than those of the biogenic polyamine-tRNA complexes, with K333 = 2.8 (+/-0.5) x 10(4), K(BE-333) = 3.7 (+/-0.7) x 10(4), K(BE-3333) = 4.0 (+/-0.9) x 10(4), K(spm) = 8.7 (+/-0.9) x 10(5), K(spd) = 6.1 (+/-0.7) x 10(5), and K(put) = 1.0 (+/-0.3) x 10(5) mol/L. tRNA remained in the A-family conformation; however, it aggregated at high polyamine analogue concentrations.

  11. Cellular Cations Control Conformational Switching of Inositol Pyrophosphate Analogues.

    PubMed

    Hager, Anastasia; Wu, Mingxuan; Wang, Huanchen; Brown, Nathaniel W; Shears, Stephen B; Veiga, Nicolás; Fiedler, Dorothea

    2016-08-22

    The inositol pyrophosphate messengers (PP-InsPs) are emerging as an important class of cellular regulators. These molecules have been linked to numerous biological processes, including insulin secretion and cancer cell migration, but how they trigger such a wide range of cellular responses has remained unanswered in many cases. Here, we show that the PP-InsPs exhibit complex speciation behaviour and propose that a unique conformational switching mechanism could contribute to their multifunctional effects. We synthesised non-hydrolysable bisphosphonate analogues and crystallised the analogues in complex with mammalian PPIP5K2 kinase. Subsequently, the bisphosphonate analogues were used to investigate the protonation sequence, metal-coordination properties, and conformation in solution. Remarkably, the presence of potassium and magnesium ions enabled the analogues to adopt two different conformations near physiological pH. Understanding how the intrinsic chemical properties of the PP-InsPs can contribute to their complex signalling outputs will be essential to elucidate their regulatory functions.

  12. Fluorescence Studies Of A Cholesterol-Analogue Probe

    NASA Astrophysics Data System (ADS)

    Drew, Jacinta; Szabo, Arthur G.; Morand, Peter

    1988-06-01

    A novel cholesterol-analogue probe1,2 with a diene-(2-naphthyl) fluorophore in the sidechain (Figure 1), hereafter referred to as DN-Chol, has had its steady-state and time-resolved fluorescence properties characterized in solvents and in various viscosity mineral oils.

  13. A new analogue of fatty alcohol from Tamarix hampeana L.

    PubMed

    Aykac, Ahmet; Akgül, Yurdanur

    2010-01-01

    New analogues of a long-chain secondary alcohol (1) and laserine (2) were isolated from the flowers of Tamarix hampeana L. The isolated compounds were identified using 1D and 2D NMR, LCMS/APCI, and chemical methods. Laserine was isolated for the first time from T. hampeana L.

  14. Cyclization of nucleotide analogues as an obstacle to polymerization

    NASA Technical Reports Server (NTRS)

    Hill, A. R. Jr; Nord, L. D.; Orgel, L. E.; Robins, R. K.

    1988-01-01

    Cyclization of activated nucleotide analogues by intramolecular phosphodiester-bond formation is likely to compete very effectively with template-directed condensation except in the cases of ribo- and arabinonucleotides. This could have excluded derivatives of most sugars from growing polyribonucleotide chains and thus reduced chain-termination in prebiotic polynucleotide synthesis.

  15. Synthesis of (+)-crocacin D and simplified bioactive analogues.

    PubMed

    Pasqua, Adele E; Ferrari, Frank D; Crawford, James J; Whittingham, William G; Marquez, Rodolfo

    2015-03-01

    The total synthesis of (+)-crocacin D has been achieved in 15 steps (9 isolated intermediates) and 14% overall yield from commercially available starting materials and using (+)-crocacin C as a key intermediate. A number of simplified analogues and their biological activities are also reported.

  16. Trehalose Analogues: Latest Insights in Properties and Biocatalytic Production

    PubMed Central

    Walmagh, Maarten; Zhao, Renfei; Desmet, Tom

    2015-01-01

    Trehalose (α-d-glucopyranosyl α-d-glucopyranoside) is a non-reducing sugar with unique stabilizing properties due to its symmetrical, low energy structure consisting of two 1,1-anomerically bound glucose moieties. Many applications of this beneficial sugar have been reported in the novel food (nutricals), medical, pharmaceutical and cosmetic industries. Trehalose analogues, like lactotrehalose (α-d-glucopyranosyl α-d-galactopyranoside) or galactotrehalose (α-d-galactopyranosyl α-d-galactopyranoside), offer similar benefits as trehalose, but show additional features such as prebiotic or low-calorie sweetener due to their resistance against hydrolysis during digestion. Unfortunately, large-scale chemical production processes for trehalose analogues are not readily available at the moment due to the lack of efficient synthesis methods. Most of the procedures reported in literature suffer from low yields, elevated costs and are far from environmentally friendly. “Greener” alternatives found in the biocatalysis field, including galactosidases, trehalose phosphorylases and TreT-type trehalose synthases are suggested as primary candidates for trehalose analogue production instead. Significant progress has been made in the last decade to turn these into highly efficient biocatalysts and to broaden the variety of useful donor and acceptor sugars. In this review, we aim to provide an overview of the latest insights and future perspectives in trehalose analogue chemistry, applications and production pathways with emphasis on biocatalysis. PMID:26084050

  17. q-bosons and the q-analogue quantized field

    NASA Technical Reports Server (NTRS)

    Nelson, Charles A.

    1995-01-01

    The q-analogue coherent states are used to identify physical signatures for the presence of a 1-analogue quantized radiation field in the q-CS classical limits where the absolute value of z is large. In this quantum-optics-like limit, the fractional uncertainties of most physical quantities (momentum, position, amplitude, phase) which characterize the quantum field are O(1). They only vanish as O(1/absolute value of z) when q = 1. However, for the number operator, N, and the N-Hamiltonian for a free q-boson gas, H(sub N) = h(omega)(N + 1/2), the fractional uncertainties do still approach zero. A signature for q-boson counting statistics is that (Delta N)(exp 2)/ (N) approaches 0 as the absolute value of z approaches infinity. Except for its O(1) fractional uncertainty, the q-generalization of the Hermitian phase operator of Pegg and Barnett, phi(sub q), still exhibits normal classical behavior. The standard number-phase uncertainty-relation, Delta(N) Delta phi(sub q) = 1/2, and the approximate commutation relation, (N, phi(sub q)) = i, still hold for the single-mode q-analogue quantized field. So, N and phi(sub q) are almost canonically conjugate operators in the q-CS classical limit. The q-analogue CS's minimize this uncertainty relation for moderate (absolute value of z)(exp 2).

  18. Thymidine analogues to assess microperfusion in human tumors

    SciTech Connect

    Janssen, Hilde L.; Ljungkvist, Anna S.; Rijken, Paul F.; Sprong, Debbie; Bussink, Jan; Kogel, Albert J. van der; Haustermans, Karin M.; Begg, Adrian C. . E-mail: a.begg@nki.nl

    2005-07-15

    Purpose: To validate the use of the thymidine analogues as local perfusion markers in human tumors (no labeling indicates no perfusion) by comparison with the well-characterized perfusion marker Hoechst 33342. Methods and Materials: Human tumor xenografts from gliomas and head-and-neck cancers were injected with iododeoxyuridine (IdUrd) or bromodeoxyuridine (BrdUrd) and the fluorescent dye Hoechst 33342. In frozen sections, each blood vessel was scored for the presence of IdUrd/BrdUrd labeling and Hoechst in surrounding cells. The percentage of analogue-negative vessels was compared with the fraction of Hoechst-negative vessels. Collocalization of the two markers was also scored. Results: We found considerable intertumor variation in the fraction of perfused vessels, measured by analogue labeling, both in the human tumor xenografts and in a series of tumor biopsies from head-and-neck cancer patients. There was a significant correlation between the Hoechst-negative and IdUrd/BrdUrd-negative vessels in the xenografts (r 85, p = 0.0004), despite some mismatches on a per-vessel basis. Conclusions: Thymidine analogues can be successfully used to rank tumors according to their fraction of perfused vessels. Whether this fraction correlates with the extent of acute hypoxia needs further confirmation.

  19. Vitamin D analogues: Potential use in cancer treatment.

    PubMed

    Duffy, Michael J; Murray, Alyson; Synnott, Naoise C; O'Donovan, Norma; Crown, John

    2017-04-01

    The vitamin D receptor (VDR) is a member of the thyroid-steroid family of nuclear transcription factors. Following binding of the active form of vitamin D, i.e., 1,25(OH)2D3 (also known as calcitriol) and interaction with co-activators and co-repressors, VDR regulates the expression of several different genes. Although relatively little work has been carried out on VDR in human cancers, several epidemiological studies suggest that low circulating levels of vitamin D are associated with both an increased risk of developing specific cancer types and poor outcome in patients with specific diagnosed cancers. These associations apply especially in colorectal and breast cancer. Consistent with these findings, calcitriol as well as several of its synthetic analogues have been shown to inhibit tumor cell growth in vitro and in diverse animal model systems. Indeed, some of these vitamin D analogues with low calcemic inducing activity (e.g., EB1089, inecalcitol, paricalcitol) have progressed to clinical trials in patients with cancer. Preliminary results from these trials suggest that these vitamin D analogues have minimal toxicity, but clear evidence of efficacy remains to be shown. Although evidence of efficacy for mono-treatment with vitamin D analogues is currently lacking, several studies have reported that supplementation with calcitriol or the presence of high endogenous circulating levels of vitamin D enhances response to standard therapies.

  20. Synthesis of chlorins, bacteriochlorins and their tetraaza analogues

    NASA Astrophysics Data System (ADS)

    Dudkin, S. V.; Makarova, E. A.; Lukyanets, E. A.

    2016-07-01

    The currently known methods for the synthesis of hydrogenated derivatives of synthetic porphyrins — chlorins, bacteriochlorins, isobacteriochlorins and their tetraaza analogues — are considered. Reactions involving quasi-isolated double bonds including reduction, oxidative addition and cycloaddition are presented. Examples of direct synthesis of these macroheterocycles are given. The bibliography includes 168 references.

  1. Methylene Blue Causing Serotonin Syndrome Following Cystocele Repair.

    PubMed

    Kapadia, Kailash; Cheung, Felix; Lee, Wai; Thalappillil, Richard; Florence, F Barry; Kim, Jason

    2016-11-01

    Methylene blue is an intravenously administered agent that may potentiate serotonin syndrome. The usage of methylene blue to evaluate ureters for injuries and patency during urological surgeries is recognized as common practice. However, there is no mention of serotonin syndrome caused by methylene blue in urological literature or for urological surgery. We report the first urological case in order to raise awareness of the risk for serotonin toxicity with utilizing methylene blue.

  2. Transition States and transition state analogue interactions with enzymes.

    PubMed

    Schramm, Vern L

    2015-04-21

    Enzymatic transition states have lifetimes of a few femtoseconds (fs). Computational analysis of enzyme motions leading to transition state formation suggests that local catalytic site motions on the fs time scale provide the mechanism to locate transition states. An experimental test of protein fs motion and its relation to transition state formation can be provided by isotopically heavy proteins. Heavy enzymes have predictable mass-altered bond vibration states without altered electrostatic properties, according to the Born-Oppenheimer approximation. On-enzyme chemistry is slowed in most heavy proteins, consistent with altered protein bond frequencies slowing the search for the transition state. In other heavy enzymes, structural changes involved in reactant binding and release are also influenced. Slow protein motions associated with substrate binding and catalytic site preorganization are essential to allow the subsequent fs motions to locate the transition state and to facilitate the efficient release of products. In the catalytically competent geometry, local groups move in stochastic atomic motion on the fs time scale, within transition state-accessible conformations created by slower protein motions. The fs time scale for the transition state motions does not permit thermodynamic equilibrium between the transition state and stable enzyme states. Isotopically heavy enzymes provide a diagnostic tool for fast coupled protein motions to transition state formation and mass-dependent conformational changes. The binding of transition state analogue inhibitors is the opposite in catalytic time scale to formation of the transition state but is related by similar geometries of the enzyme-transition state and enzyme-inhibitor interactions. While enzymatic transition states have lifetimes as short as 10(-15) s, transition state analogues can bind tightly to enzymes with release rates greater than 10(3) s. Tight-binding transition state analogues stabilize the rare but

  3. Non-robust numerical simulations of analogue extension experiments

    NASA Astrophysics Data System (ADS)

    Naliboff, John; Buiter, Susanne

    2016-04-01

    Numerical and analogue models of lithospheric deformation provide significant insight into the tectonic processes that lead to specific structural and geophysical observations. As these two types of models contain distinct assumptions and tradeoffs, investigations drawing conclusions from both can reveal robust links between first-order processes and observations. Recent studies have focused on detailed comparisons between numerical and analogue experiments in both compressional and extensional tectonics, sometimes involving multiple lithospheric deformation codes and analogue setups. While such comparisons often show good agreement on first-order deformation styles, results frequently diverge on second-order structures, such as shear zone dip angles or spacing, and in certain cases even on first-order structures. Here, we present finite-element experiments that are designed to directly reproduce analogue "sandbox" extension experiments at the cm-scale. We use material properties and boundary conditions that are directly taken from analogue experiments and use a Drucker-Prager failure model to simulate shear zone formation in sand. We find that our numerical experiments are highly sensitive to numerous numerical parameters. For example, changes to the numerical resolution, velocity convergence parameters and elemental viscosity averaging commonly produce significant changes in first- and second-order structures accommodating deformation. The sensitivity of the numerical simulations to small parameter changes likely reflects a number of factors, including, but not limited to, high angles of internal friction assigned to sand, complex, unknown interactions between the brittle sand (used as an upper crust equivalent) and viscous silicone (lower crust), highly non-linear strain weakening processes and poor constraints on the cohesion of sand. Our numerical-analogue comparison is hampered by (a) an incomplete knowledge of the fine details of sand failure and sand

  4. 49 CFR 173.216 - Asbestos, blue, brown or white.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 2 2014-10-01 2014-10-01 false Asbestos, blue, brown or white. 173.216 Section... Class 7 § 173.216 Asbestos, blue, brown or white. (a) Asbestos, blue, brown or white, includes each of the following hydrated mineral silicates: chrysolite, crocidolite, amosite, anthophyllite...

  5. 49 CFR 173.216 - Asbestos, blue, brown or white.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Asbestos, blue, brown or white. 173.216 Section... Class 7 § 173.216 Asbestos, blue, brown or white. (a) Asbestos, blue, brown or white, includes each of the following hydrated mineral silicates: chrysolite, crocidolite, amosite, anthophyllite...

  6. 49 CFR 173.216 - Asbestos, blue, brown or white.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false Asbestos, blue, brown or white. 173.216 Section... Class 7 § 173.216 Asbestos, blue, brown or white. (a) Asbestos, blue, brown or white, includes each of the following hydrated mineral silicates: chrysolite, crocidolite, amosite, anthophyllite...

  7. 49 CFR 173.216 - Asbestos, blue, brown or white.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 2 2011-10-01 2011-10-01 false Asbestos, blue, brown or white. 173.216 Section... Class 7 § 173.216 Asbestos, blue, brown or white. (a) Asbestos, blue, brown or white, includes each of the following hydrated mineral silicates: chrysolite, crocidolite, amosite, anthophyllite...

  8. 49 CFR 173.216 - Asbestos, blue, brown or white.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 2 2013-10-01 2013-10-01 false Asbestos, blue, brown or white. 173.216 Section... Class 7 § 173.216 Asbestos, blue, brown or white. (a) Asbestos, blue, brown or white, includes each of the following hydrated mineral silicates: chrysolite, crocidolite, amosite, anthophyllite...

  9. 77 FR 55895 - Permanent Closure of Cincinnati Blue Ash Airport

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-11

    ... Federal Aviation Administration Permanent Closure of Cincinnati Blue Ash Airport AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of permanent closure of Cincinnati Blue Ash Airport (ISZ). SUMMARY: The... Cincinnati advising that on August 29, 2012, it was permanently closing Cincinnati Blue Ash Airport...

  10. Is blue light good or bad for plants?

    PubMed

    Dougher, T A; Bugbee, B G

    1998-01-01

    Blue photons are energetically expensive so the most energy-efficient lamps contain the least blue light. Blue photons are not used efficiently in photosynthesis, but blue light has dramatic effects on plant development. We studied the growth and development of soybean, wheat, and lettuce plants under high-pressure sodium and metal halide lamps with yellow filters creating five fractions of blue light (0.5%, 3.5%, 6%, 1 8%, and 26% blue) at 500 micromoles m-2 s-1 and (< 0.1%, 1.7%, 6%, 12%, and 26%) at 200 mol m-2 s-1. The response was species dependent. Lettuce was highly sensitive to blue light fraction and had an optimum dry weight and leaf area at about 6% blue, but results were complicated by sensitivity to lamp type. Wheat and soybean were less sensitive to blue light, but dry mass and leaf area decreased steadily with increasing blue light. Blue light fraction significantly affected specific leaf area (SLA, m2 kg-1) and chlorophyll in lettuce, but had no significant effect on wheat and soybeans. The data suggest that lettuce benefits from some added blue light, but soybean and wheat may not.

  11. 76 FR 35909 - Temporary Concession Contract for Blue Ridge Parkway

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-20

    ...-OYC] Temporary Concession Contract for Blue Ridge Parkway AGENCY: National Park Service, Interior. ACTION: Notice of proposed award of temporary concession contracts for Blue Ridge Parkway, NC/VA. SUMMARY... award temporary concession contracts for the conduct of certain visitor services within the Blue...

  12. Analogue Sites for Mars Missions - A report from two workshops

    NASA Astrophysics Data System (ADS)

    Hipkin, V.; Voytek, M. A.; Glamoclija, M.

    2014-12-01

    Fieldwork, at terrestrial sites that are analogous in some way to Mars, has a key role in defining questions addressed by Mars missions. For MSL, the question is whether its landing site was habitable, and for Mars 2020, the question is how do we search for and what are signs of life in ancient habitable environments. Implementing these investigations by means of a rover mission on a distant planetary surface has challenges due to a limited set of tools and period of operations. Using this context of planetary missions is important in shaping how analog research can be used to advance planetary science. Following a successful 2010 AGU fall meeting session entitled "Analogue Sites for Mars Missions", two community workshops were held at The Woodlands, TX March 2011 and the Carnegie Institute of Washington in July 2013. These activities represent an ongoing dialogue with the analogue and mission communities. The AGU session solicited presentations of current analogue research relevant to MSL, at which time the landing site selection process was still considering four final sites. The 2011 Woodlands workshop solicited details on representative science questions and analogue sites by means of an abstract template. The output from The Woodlands workshop was an initial metric to assess the utility of analogue sites against specific science questions, as well as recommendations for future activities. The 2013 Carnegie workshop, followed up on some of the recommendations from 2011. Both on-line interactive dialogue and in person discussions targeted broad topics, including 'the advantages and problems of using a great terrestrial analog for field testing', and 'knowing what we currently do about Mars, what would be the best place on the planet to collect the first suite of samples to be returned to Earth? What would be appropriate analog sites on Earth?'. The results and recommendations from both workshops are summarized to publicize and stimulate this ongoing discussion.

  13. Biological evaluation of a novel sorafenib analogue, t-CUPM.

    PubMed

    Wecksler, Aaron T; Hwang, Sung Hee; Liu, Jun-Yan; Wettersten, Hiromi I; Morisseau, Christophe; Wu, Jian; Weiss, Robert H; Hammock, Bruce D

    2015-01-01

    Sorafenib (Nexavar®) is currently the only FDA-approved small molecule targeted therapy for advanced hepatocellular carcinoma. The use of structural analogues and derivatives of sorafenib has enabled the elucidation of critical targets and mechanism(s) of cell death for human cancer lines. We previously performed a structure-activity relationship study on a series of sorafenib analogues designed to investigate the inhibition overlap between the major targets of sorafenib Raf-1 kinase and VEGFR-2, and an enzyme shown to be a potent off-target of sorafenib, soluble epoxide hydrolase. In the current work, we present the biological data on our lead sorafenib analogue, t-CUPM, demonstrating that this analogue retains cytotoxicity similar to sorafenib in various human cancer cell lines and strongly inhibits growth in the NCI-60 cell line panel. Co-treatment with the pan-caspase inhibitor, Z-VAD-FMK, failed to rescue the cell viability responses of both sorafenib and t-CUPM, and immunofluorescence microscopy shows similar mitochondrial depolarization and apoptosis-inducing factor release for both compounds. These data suggest that both compounds induce a similar mechanism of caspase-independent apoptosis in hepatoma cells. In addition, t-CUPM displays anti-proliferative effects comparable to sorafenib as seen by a halt in G0/G1 in cell cycle progression. The structural difference between sorafenib and t-CUPM significantly reduces inhibitory spectrum of kinases by this analogue, and pharmacokinetic characterization demonstrates a 20-fold better oral bioavailability of t-CUPM than sorafenib in mice. Thus, t-CUPM may have the potential to reduce the adverse events observed from the multikinase inhibitory properties and the large dosing regimens of sorafenib.

  14. Sulphamoylated 2-Methoxyestradiol Analogues Induce Apoptosis in Adenocarcinoma Cell Lines

    PubMed Central

    Visagie, Michelle; Theron, Anne; Mqoco, Thandi; Vieira, Warren; Prudent, Renaud; Martinez, Anne; Lafanechère, Laurence; Joubert, Annie

    2013-01-01

    2-Methoxyestradiol (2ME2) is a naturally occurring estradiol metabolite which possesses antiproliferative, antiangiogenic and antitumor properties. However, due to its limited biological accessibility, synthetic analogues have been synthesized and tested in attempt to develop drugs with improved oral bioavailability and efficacy. The aim of this study was to evaluate the antiproliferative effects of three novel in silico-designed sulphamoylated 2ME2 analogues on the HeLa cervical adenocarcinoma cell line and estrogen receptor-negative breast adenocarcinoma MDA-MB-231 cells. A dose-dependent study (0.1–25 μM) was conducted with an exposure time of 24 hours. Results obtained from crystal violet staining indicated that 0.5 μM of all 3 compounds reduced the number of cells to 50%. Lactate dehydrogenase assay was used to assess cytotoxicity, while the mitotracker mitochondrial assay and caspase-6 and -8 activity assays were used to investigate the possible occurrence of apoptosis. Tubulin polymerization assays were conducted to evaluate the influence of these sulphamoylated 2ME2 analogues on tubulin dynamics. Double immunofluorescence microscopy using labeled antibodies specific to tyrosinate and detyrosinated tubulin was conducted to assess the effect of the 2ME2 analogues on tubulin dynamics. An insignificant increase in the level of lactate dehydrogenase release was observed in the compounds-treated cells. These sulphamoylated compounds caused a reduction in mitochondrial membrane potential, cytochrome c release and caspase 3 activation indicating apoptosis induction by means of the intrinsic pathway in HeLa and MDA-MB-231 cells. Microtubule depolymerization was observed after exposure to these three sulphamoylated analogues. PMID:24039728

  15. Neurochemical binding profiles of novel indole and benzofuran MDMA analogues.

    PubMed

    Shimshoni, Jakob A; Winkler, Ilan; Golan, Ezekiel; Nutt, David

    2017-01-01

    3,4-Methylenedioxy-N-methylamphetamine (MDMA) has been shown to be effective in the treatment of post-traumatic stress disorder (PTSD) in numerous clinical trials. In the present study, we have characterized the neurochemical binding profiles of three MDMA-benzofuran analogues (1-(benzofuran-5-yl)-propan-2-amine, 5-APB; 1-(benzofuran-6-yl)-N-methylpropan-2-amine, 6-MAPB; 1-(benzofuran-5-yl)-N-methylpropan-2-amine, 5-MAPB) and one MDMA-indole analogue (1-(1H-indol-5-yl)-2-methylamino-propan-1-ol, 5-IT). These compounds were screened as potential second-generation anti-PTSD drugs, against a battery of human and non-human receptors, transporters, and enzymes, and their potencies as 5-HT2 receptor agonist and monoamine uptake inhibitors determined. All MDMA analogues displayed high binding affinities for 5-HT2a,b,c and NEα2 receptors, as well as significant 5-HT, DA, and NE uptake inhibition. 5-APB revealed significant agonist activity at the 5-HT2a,b,c receptors, while 6-MAPB, 5-MAPB, and 5-IT exhibited significant agonist activity at the 5-HT2c receptor. There was a lack of correlation between the results of functional uptake and the monoamine transporter binding assay. MDMA analogues emerged as potent and selective monoamine oxidase A inhibitors. Based on 6-MAPB favorable pharmacological profile, it was further subjected to IC50 determination for monoamine transporters. Overall, all MDMA analogues displayed higher monoamine receptor/transporter binding affinities and agonist activity at the 5-HT2a,c receptors as compared to MDMA.

  16. Cysteine analogues potentiate glucose-induced insulin release in vitro

    SciTech Connect

    Ammon, H.P.; Hehl, K.H.; Enz, G.; Setiadi-Ranti, A.; Verspohl, E.J.

    1986-12-01

    In rat pancreatic islets, cysteine analogues, including glutathione, acetylcysteine, cysteamine, D-penicillamine, L-cysteine ethyl ester, and cysteine-potentiated glucose (11.1 mM) induced insulin secretion in a concentration-dependent manner. Their maximal effects were similar and occurred at approximately 0.05, 0.05, 0.1, 0.5, 1.0, 1.0 mM, respectively. At substimulatory glucose levels (2.8 mM), insulin release was not affected by these compounds. In contrast, thiol compounds, structurally different from cysteine and its analogues, such as mesna, tiopronin, meso-2,3-dimercaptosuccinic acid (DMSA), dimercaprol (BAL), beta-thio-D-glucose, as well as those cysteine analogues that lack a free-thiol group, including L-cystine, cystamine, D-penicillamine disulfide, S-carbocysteine, and S-carbamoyl-L-cysteine, did not enhance insulin release at stimulatory glucose levels (11.1 mM); cystine (5 mM) was inhibitory. These in vitro data indicate that among the thiols tested here, only cysteine and its analogues potentiate glucose-induced insulin secretion, whereas thiols that are structurally not related to cysteine do not. This suggests that a cysteine moiety in the molecule is necessary for the insulinotropic effect. For their synergistic action to glucose, the availability of a sulfhydryl group is also a prerequisite. The maximal synergistic action is similar for all cysteine analogues tested, whereas the potency of action is different, suggesting similarity in the mechanism of action but differences in the affinity to the secretory system.

  17. 78 FR 19413 - Listing of Color Additives Exempt From Certification; Reactive Blue 246 and Reactive Blue 247...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-01

    ... C.I. Reactive Blue 246. Studies included guinea pig maximization studies, in vivo ocular irritation... copolymerized color additives of C. I. Reactive Blue 247. Studies included guinea pig maximization studies,...

  18. Muraymycins, novel peptidoglycan biosynthesis inhibitors: synthesis and SAR of their analogues.

    PubMed

    Yamashita, Ayako; Norton, Emily; Petersen, Peter J; Rasmussen, Beth A; Singh, Guy; Yang, Youjin; Mansour, Tarek S; Ho, Douglas M

    2003-10-06

    A series of Muraymycin analogues was synthesized. These analogues showed excellent antimicrobial activity against gram-positive organisms. These analogues also showed excellent inhibitory activity against the target peptidoglycan biosynthesis enzyme MraY, the cell membrane associated transglycosylase responsible for the formation of Lipid II.

  19. Acute blue finger: a diagnostic challenge

    PubMed Central

    Farag, Mohamed; Elmasry, Mohamed; Mabote, Thato; Elsayed, Ayman; Sunthareswaran, Rame

    2014-01-01

    The management of the acute blue finger is controversial with many regarding it as a benign condition. However, we would argue that it should always be considered as an emergency. We present a challenging case of a 43-year-old woman who presented with a 1-week history of sudden onset blue discolouration of the left fifth digit, and a 6-week history of episodic joint problems. Examination showed bilateral normal radial and ulnar pulses. Following blood investigations, an initial working diagnosis of early rheumatoid arthritis with associated Raynaud's phenomenon was made. Also, infective endocarditis was considered due to temporary misleading physical signs. Later, CT angiography of the left upper limb arteries showed a significant proximal left subclavian stenosis. Subsequently, a diagnosis of the left subclavian arteritis associated with digit ischaemia from embolic debris was made and the patient underwent a left subclavian angioplasty. However, delayed management resulted in a necrotic digit, which was left to autoamputate. PMID:24429047

  20. Epikeratoplasty for keratoglobus associated with blue sclera.

    PubMed

    Cameron, J A; Cotter, J B; Risco, J M; Alvarez, H

    1991-04-01

    Patients with keratoglobus and blue sclera as part of a generalized connective tissue disorder are at a high risk of developing corneal perforations either spontaneously or after mild trauma. Six patients (6 eyes) between the ages of 2 and 16 years of age (mean, 7.5 years) with keratoglobus, blue sclera, hypermobile joints, and consanguineous parents were treated by epikeratoplasty, using commercially prepared 12.5-mm lenticules. Surgery was performed for tectonic support and/or visual improvement and was successful in five of six patients with a follow-up period of 11 to 27 months (mean, 21 months). One lenticule was removed because the epithelium did not heal. Peripheral interface opacities occurred in three patients.

  1. Experiencing Blues at the Crossroads: A Place-Based Method for Teaching the Geography of Blues Culture

    ERIC Educational Resources Information Center

    Strait, John

    2012-01-01

    This article offers a pedagogical module that explores the geography of blues culture across the Mississippi Delta. By focusing on blues culture, rather than simply blues music itself, this project provides a forum for understanding the broader geographical conditions from which this musical form emerged. This module utilizes place-based…

  2. Blue-Green Lasers and Electrodeless Flashlamps

    DTIC Science & Technology

    1983-08-01

    very helpful. W. Krupke of the Lawrence Livermore Laboratory contributed useful discussions on high power solid-state lasers . Financial support was...Blue-Green Lasers and Electrodeless Flashlamps F. W. Perkins CIAM * Accesion For7 DTIC TAB [] Urnannouriced lI Justification By...combining the technology of moderate pressure electrodeless discharge lamps with the efficiency of a resonantly pumped solid-state laser to achieve an

  3. Indicator characteristics of bromothymol blue derivatives.

    PubMed

    Puschett, J B; Rao, B S; Karandikar, B M; Matyjaszewski, K

    1991-03-01

    Some Bromothymol Blue derivatives with a nitro, amino, isothiocyanato or sulfonamide group substituted on the sulfonated ring of the dibromothymolsulfonephthalein have been studied spectrometrically. All the dyes have two characteristic absorption peaks which can be used to measure pH in the physiological range. The molar absorptivities, wavelengths of maximum absorption and pK(a) values have been determined from the absorbances, and are similar for all four dyes.

  4. Eta Carinae and Other Luminous Blue Variables

    NASA Technical Reports Server (NTRS)

    Corcoran, M. F.

    2006-01-01

    Luminous Blue Variables (LBVs) are believed to be evolved, extremely massive stars close to the Eddington Limit and hence prone to bouts of large-scale, unstable mass loss. I discuss current understanding of the evolutionary state of these objects, the role duplicity may play and known physical characteristics of these stars using the X-ray luminous LBVs Eta Carinae and HD 5980 as test cases.

  5. Luminescence conversion of blue light emitting diodes

    NASA Astrophysics Data System (ADS)

    Schlotter, P.; Schmidt, R.; Schneider, J.

    Using blue-emitting GaN/6HSiC chips as primary light sources, we have fabricated green, yellow, red and white emitting LEDs. The generation of mixed colors, as turquoise and magenta is also demonstrated. The underlying physical principle is that of luminescence down-conversion (Stokes shift), as typical for organic luminescent dye molecules. A white emitting LED, using an inorganic converter, Y3Al5O12:Ce3+( ), has also been realized.

  6. Blue Rose perimeter defense and security system

    NASA Astrophysics Data System (ADS)

    Blackmon, F.; Pollock, J.

    2006-05-01

    An in-ground perimeter security system has been developed by the Naval Undersea Warfare Center Division Newport based upon fiber optic sensor technology. The system, called Blue Rose, exploits the physical phenomenon of Rayleigh optical scattering, which occurs naturally in optical fibers used traditionally for Optical Time Domain Reflectometry techniques to detect sound and vibration transmitted by intruders such as people walking or running and moving vehicles near the sensor. The actual sensor is a single-mode optical fiber with an elastomeric coating that is buried in the ground. A long coherence length laser is used to transmit encoded light down the fiber. Minute changes in the fiber in response to the intrusion produce phase changes to the returning backscattered light signal. The return light signal contains both the actual intrusion sound and the location information of where along the fiber the intrusion has occurred. A digital, in-ground, Blue Rose system has been built and is now operational at NUWC. Due to the low cost of the optical fiber sensor and unique benefits of the system, the Blue Rose system provides an advantage in long perimeter or border security applications and also reduces security manning requirements and therefore overall cost for security.

  7. Automated detection of Antarctic blue whale calls.

    PubMed

    Socheleau, Francois-Xavier; Leroy, Emmanuelle; Pecci, Andres Carvallo; Samaran, Flore; Bonnel, Julien; Royer, Jean-Yves

    2015-11-01

    This paper addresses the problem of automated detection of Z-calls emitted by Antarctic blue whales (B. m. intermedia). The proposed solution is based on a subspace detector of sigmoidal-frequency signals with unknown time-varying amplitude. This detection strategy takes into account frequency variations of blue whale calls as well as the presence of other transient sounds that can interfere with Z-calls (such as airguns or other whale calls). The proposed method has been tested on more than 105 h of acoustic data containing about 2200 Z-calls (as found by an experienced human operator). This method is shown to have a correct-detection rate of up to more than 15% better than the extensible bioacoustic tool package, a spectrogram-based correlation detector commonly used to study blue whales. Because the proposed method relies on subspace detection, it does not suffer from some drawbacks of correlation-based detectors. In particular, it does not require the choice of an a priori fixed and subjective template. The analytic expression of the detection performance is also derived, which provides crucial information for higher level analyses such as animal density estimation from acoustic data. Finally, the detection threshold automatically adapts to the soundscape in order not to violate a user-specified false alarm rate.

  8. The Blue Comet: A Railroad's Astronomical Heritage

    NASA Astrophysics Data System (ADS)

    Rumstay, Kenneth S.

    2009-01-01

    Between 1929 February 21 and 1941 September 27, the Central New Jersey Railroad operated a luxury passenger train between Jersey City and Atlantic City. Named The Blue Comet, the locomotive, tender, and coaches sported a unique royal blue paint scheme designed to evoke images of celestial bodies speeding through space. Inside each car were etched window panes and lampshades featuring stars and comets. And each coach sported the name of a famous comet on its side; these comets were of course named for their discoverers. Some of the astronomers honored in this unique fashion remain famous to this day, or at least their comets do. The names D'Arrest, Barnard, Encke, Faye, Giacobini, Halley, Olbers, Temple, Tuttle, and Westphal are familiar ones. But Biela, Brorsen, deVico, Spitaler, and Winnecke have now largely faded into obscurity; their stories are recounted here. Although more than sixty years have elapsed since its last run, The Blue Comet, perhaps the most famous passenger train in American history, lives on in the memories of millions of passengers and railfans. This famous train returned to the attention of millions of television viewers on the evening of 2007 June 3, in an episode of the HBO series The Sopranos. This work was supported by a faculty development grant from Valdosta State University.

  9. Blue Fermi flat spectrum radio quasars

    NASA Astrophysics Data System (ADS)

    Ghisellini, G.; Tavecchio, F.; Foschini, L.; Sbarrato, T.; Ghirlanda, G.; Maraschi, L.

    2012-09-01

    Many blazars detected by the Fermi satellite, observed spectroscopically in the optical, are line-less, and have been classified as BL Lac objects. Optical-ultraviolet (UV) photometry of nearly 100 of them allowed us to determine the redshift for a handful of objects and redshift upper limits in the great majority. A few of these are candidates to be 'blue quasars', namely flat spectrum radio quasars whose broad emission lines are hidden by an overwhelming synchrotron emission peaking in the UV. This implies that the emitting electrons have high energies. In turn, this requires relatively weak radiative cooling, a condition that can be met if the main radiative dissipation of the jet power occurs outside the broad-line region. We confirm this hypothesis by studying and modelling the spectral energy distributions of the four 'blue quasars' recently discovered. Furthermore, we discuss the distribution of Fermi blazars in the γ-ray spectral index-γ-ray luminosity plane, and argue that 'blue quasars' objects are a minority within the blazar populations.

  10. QCD and the BlueGene

    SciTech Connect

    Vranas, P

    2007-06-18

    Quantum Chromodynamics is the theory of nuclear and sub-nuclear physics. It is a celebrated theory and one of its inventors, F. Wilczek, has termed it as '... our most perfect physical theory'. Part of this is related to the fact that QCD can be numerically simulated from first principles using the methods of lattice gauge theory. The computational demands of QCD are enormous and have not only played a role in the history of supercomputers but are also helping define their future. Here I will discuss the intimate relation of QCD and massively parallel supercomputers with focus on the Blue Gene supercomputer and QCD thermodynamics. I will present results on the performance of QCD on the Blue Gene as well as physics simulation results of QCD at temperatures high enough that sub-nuclear matter transitions to a plasma state of elementary particles, the quark gluon plasma. This state of matter is thought to have existed at around 10 microseconds after the big bang. Current heavy ion experiments are in the quest of reproducing it for the first time since then. And numerical simulations of QCD on the Blue Gene systems are calculating the theoretical values of fundamental parameters so that comparisons of experiment and theory can be made.

  11. Methylene blue promotes quiescence of rat neural progenitor cells.

    PubMed

    Xie, Luokun; Choudhury, Gourav R; Wang, Jixian; Park, Yong; Liu, Ran; Yuan, Fang; Zhang, Chun-Li; Yorio, Thomas; Jin, Kunlin; Yang, Shao-Hua

    2014-01-01

    Neural stem cell-based treatment holds a new therapeutic opportunity for neurodegenerative disorders. Here, we investigated the effect of methylene blue on proliferation and differentiation of rat neural progenitor cells (NPCs) both in vitro and in vivo. We found that methylene blue inhibited proliferation and promoted quiescence of NPCs in vitro without affecting committed neuronal differentiation. Consistently, intracerebroventricular infusion of methylene blue significantly inhibited NPC proliferation at the subventricular zone (SVZ). Methylene blue inhibited mTOR signaling along with down-regulation of cyclins in NPCs in vitro and in vivo. In summary, our study indicates that methylene blue may delay NPC senescence through enhancing NPCs quiescence.

  12. Nature's palette: the search for natural blue colorants.

    PubMed

    Newsome, Andrew G; Culver, Catherine A; van Breemen, Richard B

    2014-07-16

    The food and beverage industry is seeking to broaden the palette of naturally derived colorants. Although considerable effort has been devoted to the search for new blue colorants in fruits and vegetables, less attention has been directed toward blue compounds from other sources such as bacteria and fungi. The current work reviews known organic blue compounds from natural plant, animal, fungal, and microbial sources. The scarcity of blue-colored metabolites in the natural world relative to metabolites of other colors is discussed, and structural trends common among natural blue compounds are identified. These compounds are grouped into seven structural classes and evaluated for their potential as new color additives.

  13. Postnatal blues: a risk factor for postnatal depression.

    PubMed

    Henshaw, C; Foreman, D; Cox, J

    2004-01-01

    Postnatal blues have been regarded as brief, benign and without clinical significance. However, several studies have proposed a link between blues and subsequent depression but have methodological problems. We report a prospective, controlled study of postpartum women with severe blues which uses systematically devised and validated instruments for that purpose which tests the hypothesis that severe blues increases the risk of depression in the six months following childbirth. 206 first-time mothers were recruited in late pregnancy. Blues status was defined using the Blues Questionnaire and those with severe blues and their controls who had no blues (matched for age, marital status and social class) were followed for 6 months with postal Edinburgh Postnatal Depression Scale. RDC diagnoses were made following SADS-L interview at the end of the protocol. Backwards stepwise Cox regression analysis found severe blues and past history of depression to be independent predictors each raising the risk by almost 3 times. Depression in those with severe blues onset sooner after delivery and lasted longer. The difference was largely accounted for by major depression. Severe postpartum blues are identified as an independent risk factor for subsequent postpartum depression. Screening and intervention programs could be devised.

  14. Synthesis and antioxidant activity of peptide-based ebselen analogues.

    PubMed

    Satheeshkumar, Kandhan; Mugesh, Govindasamy

    2011-04-18

    A series of di- and tripeptide-based ebselen analogues has been synthesized. The compounds were characterized by (1)H, (13)C, and (77)Se NMR spectroscopy and mass spectral techniques. The glutathione peroxidase (GPx)-like antioxidant activity has been studied by using H(2)O(2) , tert-butyl hydroperoxide (tBuOOH), and cumene hydroperoxide (Cum-OOH) as substrates, and glutathione (GSH) as a cosubstrate. Although all the peptide-based compounds have a selenazole ring similar to that of ebselen, the GPx activity of these compounds highly depends on the nature of the peptide moiety attached to the nitrogen atom of the selenazole ring. It was observed that the introduction of a phenylalanine (Phe) amino acid residue in the N-terminal reduces the activity in all three peroxide systems. On the other hand, the introduction of aliphatic amino acid residues such as valine (Val) significantly enhances the GPx activity of the ebselen analogues. The difference in the catalytic activity of dipeptide-based ebselen derivatives can be ascribed mainly to the change in the reactivity of these compounds toward GSH and peroxide. Although the presence of the Val-Ala-CO(2) Me moiety facilitates the formation of a catalytically active selenol species, the reaction of ebselen analogues that has a Phe-Ile-CO(2) Me residue with GSH does not generate the corresponding selenol. To understand the antioxidant activity of the peptide-based ebselen analogues in the absence of GSH, these compounds were studied for their ability to inhibit peroxynitrite (PN)-mediated nitration of bovine serum albumin (BSA) and oxidation of dihydrorhodamine 123. In contrast to the GPx activity, the PN-scavenging activity of the Phe-based peptide analogues was found to be comparable to that of the Val-based compounds. However, the introduction of an additional Phe residue to the ebselen analogue that had a Val-Ala dipeptide significantly reduced the potency of the parent compound in PN-mediated nitration.

  15. An analogue conceptual rainfall-runoff model for educational purposes

    NASA Astrophysics Data System (ADS)

    Herrnegger, Mathew; Riedl, Michael; Schulz, Karsten

    2016-04-01

    Conceptual rainfall-runoff models, in which runoff processes are modelled with a series of connected linear and non-linear reservoirs, remain widely applied tools in science and practice. Additionally, the concept is appreciated in teaching due to its somewhat simplicity in explaining and exploring hydrological processes of catchments. However, when a series of reservoirs are used, the model system becomes highly parametrized and complex and the traceability of the model results becomes more difficult to explain to an audience not accustomed to numerical modelling. Since normally the simulations are performed with a not visible digital code, the results are also not easily comprehensible. This contribution therefore presents a liquid analogue model, in which a conceptual rainfall-runoff model is reproduced by a physical model. This consists of different acrylic glass containers representing different storage components within a catchment, e.g. soil water or groundwater storage. The containers are equipped and connected with pipes, in which water movement represents different flow processes, e.g. surface runoff, percolation or base flow. Water from a storage container is pumped to the upper part of the model and represents effective rainfall input. The water then flows by gravity through the different pipes and storages. Valves are used for controlling the flows within the analogue model, comparable to the parameterization procedure in numerical models. Additionally, an inexpensive microcontroller-based board and sensors are used to measure storage water levels, with online visualization of the states as time series data, building a bridge between the analogue and digital world. The ability to physically witness the different flows and water levels in the storages makes the analogue model attractive to the audience. Hands-on experiments can be performed with students, in which different scenarios or catchment types can be simulated, not only with the analogue but

  16. Quality issues in blue noise halftoning

    NASA Astrophysics Data System (ADS)

    Yu, Qing; Parker, Kevin J.

    1998-01-01

    The blue noise mask (BNM) is a halftone screen that produces unstructured visually pleasing dot patterns. The BNM combines the blue-noise characteristics of error diffusion and the simplicity of ordered dither. A BNM is constructed by designing a set of interdependent binary patterns for individual gray levels. In this paper, we investigate the quality issues in blue-noise binary pattern design and mask generation as well as in application to color reproduction. Using a global filtering technique and a local 'force' process for rearranging black and white pixels, we are able to generate a series of binary patterns, all representing a certain gray level, ranging from white-noise pattern to highly structured pattern. The quality of these individual patterns are studied in terms of low-frequency structure and graininess. Typically, the low-frequency structure (LF) is identified with a measurement of the energy around dc in the spatial frequency domain, while the graininess is quantified by a measurement of the average minimum distance (AMD) between minority dots as well as the kurtosis of the local kurtosis distribution (KLK) for minority pixels of the binary pattern. A set of partial BNMs are generated by using the different patterns as unique starting 'seeds.' In this way, we are able to study the quality of binary patterns over a range of gray levels. We observe that the optimality of a binary pattern for mask generation is related to its own quality mertirc values as well as the transition smoothness of those quality metric values over neighboring levels. Several schemes have been developed to apply blue-noise halftoning to color reproduction. Different schemes generate halftone patterns with different textures. In a previous paper, a human visual system (HVS) model was used to study the color halftone quality in terms of luminance and chrominance error in CIELAB color space. In this paper, a new series of psycho-visual experiments address the 'preferred' color

  17. Microvascular effects of selective prostaglandin analogues in the eye with special reference to latanoprost and glaucoma treatment.

    PubMed

    Stjernschantz, J; Selén, G; Astin, M; Resul, B

    2000-07-01

    including vasodilatation, increased capillary permeability, and a breakdown of the blood-aqueous barrier. 17-phenyl-PGF(2alpha)-IE, 15-keto-17-phenyl-PGF(2alpha)-IE, and PhXA34/latanoprost exerted significantly less vasodilatory effect, and little effect on capillary permeability was seen with the FP receptor agonists when studied with Evans blue. Intravenous administration of PhXA34 at a dose range of 1-100 microg/kg b.w. had no consistent effect on the regional blood flow in the eye indicating that FP receptors in the ocular blood vessels are not expressed in the rabbit, or alternatively are not functionally coupled to regulation of vascular tone. In cats topical application of PGF(2alpha)-IE had no significant effect the on the regional blood flow in cannulated eyes. No blood flow experiments were performed in intact eyes with PGF(2alpha)-IE. 17-phenyl-PGF(2alpha)-IE and latanoprost caused some vasodilation in the anterior segment. None of the analogues had any significant effect on the blood volume in the ocular tissues, but an increase in capillary permeability to albumin was seen in several tissues of the eye. However, in the eyelid, nictitating membrane and conjunctiva exposed to high concentrations of the prostaglandins no or only little leakage of albumin was detected. It appears that the intraocular microvasculature in the cat exhibits some sensitivity to FP prostanoid receptor agonists. (ABSTRACT TRUNCATED)

  18. For-profit conversion and merger trends among Blue Cross Blue Shield health plans.

    PubMed

    Grossman, Joy M; Strunk, Bradley C

    2004-01-01

    Blue Cross and Blue Shield (BCBS) health plans, which insure nearly one in three Americans, historically have operated as local, nonprofit or mutual organizations. However, since the mid-1990s, BCBS plans increasingly have converted to for-profit companies and merged with Blue plans in other states. State insurance regulators, charged with weighing the costs and benefits of conversions and mergers to consumers, often wrestle with the legal complexities of these deals, according to Center for Studying Health System Change (HSC) site visits to 12 nationally representative communities. Although state regulatory scrutiny has slowed the pace of conversions recently, conversion activity is likely to accelerate again as the political and regulatory landscapes shift and plans adapt conversion strategies. The limited evidence available from HSC site visits and conversion proceedings suggests that conversions and mergers have had neither significant negative nor positive effects on consumers.

  19. Synthetic silvestrol analogues as potent and selective protein synthesis inhibitors.

    PubMed

    Liu, Tao; Nair, Somarajan J; Lescarbeau, André; Belani, Jitendra; Peluso, Stéphane; Conley, James; Tillotson, Bonnie; O'Hearn, Patrick; Smith, Sherri; Slocum, Kelly; West, Kip; Helble, Joseph; Douglas, Mark; Bahadoor, Adilah; Ali, Janid; McGovern, Karen; Fritz, Christian; Palombella, Vito J; Wylie, Andrew; Castro, Alfredo C; Tremblay, Martin R

    2012-10-25

    Misregulation of protein translation plays a critical role in human cancer pathogenesis at many levels. Silvestrol, a cyclopenta[b]benzofuran natural product, blocks translation at the initiation step by interfering with assembly of the eIF4F translation complex. Silvestrol has a complex chemical structure whose functional group requirements have not been systematically investigated. Moreover, silvestrol has limited development potential due to poor druglike properties. Herein, we sought to develop a practical synthesis of key intermediates of silvestrol and explore structure-activity relationships around the C6 position. The ability of silvestrol and analogues to selectively inhibit the translation of proteins with high requirement on the translation-initiation machinery (i.e., complex 5'-untranslated region UTR) relative to simple 5'UTR was determined by a cellular reporter assay. Simplified analogues of silvestrol such as compounds 74 and 76 were shown to have similar cytotoxic potency and better ADME characteristics relative to those of silvestrol.

  20. Noncommutative analogue Aharonov-Bohm effect and superresonance

    NASA Astrophysics Data System (ADS)

    Anacleto, M. A.; Brito, F. A.; Passos, E.

    2013-06-01

    We consider the idea of modeling a rotating acoustic black hole by an idealized draining bathtub vortex which is a planar circulating flow phenomenon with a sink at the origin. We find the acoustic metric for this phenomenon from a noncommutative Abelian Higgs model. As such the acoustic metric not only describes a rotating acoustic black hole but also inherits the noncommutative characteristic of the spacetime. We address the issues of superresonance and analogue Aharonov-Bohm (AB) effect in this background. We mainly show that the scattering of planar waves by a draining bathtub vortex leads to a modified AB effect and due to spacetime noncommutativity, the phase shift persists even in the limit where the parameters associated with the circulation and draining vanish. Finally, we also find that the analogue AB effect and superresonance are competing phenomena at a noncommutative spacetime.

  1. Neutral Diboron Analogues of Archetypal Aromatic Species by Spontaneous Cycloaddition.

    PubMed

    Arrowsmith, Merle; Böhnke, Julian; Braunschweig, Holger; Celik, Mehmet Ali; Claes, Christina; Ewing, William C; Krummenacher, Ivo; Lubitz, Katharina; Schneider, Christoph

    2016-09-05

    Among the numerous routes organic chemists have developed to synthesize benzene derivatives and heteroaromatic compounds, transition-metal-catalyzed cycloaddition reactions are the most elegant. In contrast, cycloaddition reactions of heavier alkene and alkyne analogues, though limited in scope, proceed uncatalyzed. In this work we present the first spontaneous cycloaddition reactions of lighter alkene and alkyne analogues. Selective addition of unactivated alkynes to boron-boron multiple bonds under ambient conditions yielded diborocarbon equivalents of simple aromatic hydrocarbons, including the first neutral 6 π-aromatic diborabenzene compound, a 2 π-aromatic triplet biradical 1,3-diborete, and a phosphine-stabilized 2 π-homoaromatic 1,3-dihydro-1,3-diborete. DFT calculations suggest that all three compounds are aromatic and show frontier molecular orbitals matching those of the related aromatic hydrocarbons, C6 H6 and C4 H4 (2+) , and homoaromatic C4 H5 (+) .

  2. Highly potent metallopeptide analogues of luteinizing hormone-releasing hormone

    SciTech Connect

    Bajusz, S.; Janaky, T.; Csernus, V.J.; Bokser, L.; Fekete, M.; Srkalovic, G.; Redding, T.W.; Schally, A.V. )

    1989-08-01

    Metal complexes related to the cytotoxic complexes cisplatin (cis-diamminedichloroplatinum(II)) and transbis(salicylaldoximato)copper(II) were incorporated into suitably modified luteinizing hormone-releasing hormone (LH-RH) analogues containing D-lysine at position 6. Some of the metallopeptides thus obtained proved to be highly active LH-RH agonists or antagonists. Most metallopeptide analogues of LH-RH showed high affinities for the membrane receptors of rat pituitary and human breast cancer cells. Some of these metallopeptides had cytotoxic activity against human breast cancer and prostate cancer and prostate cancer cell lines in vitro. Such cytostatic metallopeptides could be envisioned as targeted chemotherapeutic agents in cancers that contain receptors for LH-RH-like peptides.

  3. All-dielectric metasurface analogue of electromagnetically induced transparency.

    PubMed

    Yang, Yuanmu; Kravchenko, Ivan I; Briggs, Dayrl P; Valentine, Jason

    2014-12-16

    Metasurface analogues of electromagnetically induced transparency (EIT) have been a focus of the nanophotonics field in recent years, due to their ability to produce high-quality factor (Q-factor) resonances. Such resonances are expected to be useful for applications such as low-loss slow-light devices and highly sensitive optical sensors. However, ohmic losses limit the achievable Q-factors in conventional plasmonic EIT metasurfaces to values <~10, significantly hampering device performance. Here we experimentally demonstrate a classical analogue of EIT using all-dielectric silicon-based metasurfaces. Due to extremely low absorption loss and coherent interaction of neighbouring meta-atoms, a Q-factor of 483 is observed, leading to a refractive index sensor with a figure-of-merit of 103. Furthermore, we show that the dielectric metasurfaces can be engineered to confine the optical field in either the silicon resonator or the environment, allowing one to tailor light-matter interaction at the nanoscale.

  4. New homoisoflavonoid analogues protect cells by regulating autophagy.

    PubMed

    Gan, Li-She; Zeng, Lin-Wei; Li, Xiang-Rong; Zhou, Chang-Xin; Li, Jie

    2017-03-15

    As a special group of naturally occurring flavonoids, homoisoflavonoids have been discovered as active components of several traditional Chinese medicines for nourishing heart and mind. In this study, twenty homoisoflavonoid analogues, including different substitution groups on rings A and B, as well as heteroaromatic B ring, were synthesized and evaluated for their cardioprotective and neuroprotective activities. In a H2O2-induced H9c2 cardiomyocytes injury assay, nine homoisoflavonoid analogues showed promising activities in the same level as the positive control, diazoxide. Six cardioprotective compounds with representative structure diversities were then evaluated for their neuroprotective effects on MPP+ induced SH-SY5Y cell injury model. Furthermore, autophagy inducing monodansylcadaverine (MDC) fluorescence staining methods and molecular docking studies indicated the action mechanism of these compounds may involve autophagy regulating via class I PI3K signaling pathway.

  5. New selenium-75 labeled radiopharmaceuticals: selenonium analogues of dopamine

    SciTech Connect

    Sadek, S.A.; Basmadjian, G.P.; Hsu, P.M.; Rieger, J.A.

    1983-07-01

    Selenium-75 labeled selenonium analogues of dopamine, (2-(3,4-dimethoxyphenyl)ethyl)dimethylselenonium iodide and its dihydroxy analogue, were prepared by reducing (/sup 75/Se)selenious acid with sodium borohydride at pH 6.0 and reacting the NaSeH produced with 1-(3,4-dimethoxyphenyl)-2-(p-toluenesulfonyloxy)ethane. Tissue distribution studies in rats given the /sup 75/Se-labeled selenonium agents intravenously demonstrated high initial heart uptake. Prolonged adrenal retention and high adrenal to blood ratio of compound 4 were observed. The high uptake and adrenal to blood ratio suggest the potential use of compound 4 as a radiopharmaceutical for the adrenal gland.

  6. Geoscience in Support of a Mars Methane Analogue Mission

    NASA Astrophysics Data System (ADS)

    Boivin, Alexandre

    The Mars Methane Analogue Mission, funded by the Canadian Space Agency through its Analogue Missions program, simulates a Mars rover mission whose purpose is to detect, analyse, and determine the source of methane emissions on the planet's surface. As part of this project, both an electromagnetic induction sounder (EMIS) and a high-resolution triangulation-based 3D laser scanner were tested in the field to demonstrate the benefit of including these instruments on future rover missions. EMIS data was inverted in order to derive information on the conductivity and magnetic susceptibility of the near subsurface. 3D laser scanner data was processed with fracture detection as a goal in order to simplify the search for areas of potential methane seepage. Both instruments were found to be very valuable for future rover missions of this type.

  7. A rationally designed CD4 analogue inhibits experimental allergic encephalomyelitis

    NASA Astrophysics Data System (ADS)

    Jameson, Bradford A.; McDonnell, James M.; Marini, Joseph C.; Korngold, Robert

    1994-04-01

    EXPERIMENTAL allergic encephalomyelitis (EAE) is an acute inflammatory autoimmune disease of the central nervous system that can be elicited in rodents and is the major animal model for the study of multiple sclerosis (MS)1,2. The pathogenesis of both EAE and MS directly involves the CD4+ helper T-cell subset3-5. Anti-CD4 monoclonal antibodies inhibit the development of EAE in rodents6-9, and are currently being used in human clinical trials for MS. We report here that similar therapeutic effects can be achieved in mice using a small (rationally designed) synthetic analogue of the CD4 protein surface. It greatly inhibits both clinical incidence and severity of EAE with a single injection, but does so without depletion of the CD4+ subset and without the inherent immunogenicity of an antibody. Furthermore, this analogue is capable of exerting its effects on disease even after the onset of symptoms.

  8. Optical analogue of relativistic Dirac solitons in binary waveguide arrays

    SciTech Connect

    Tran, Truong X.; Longhi, Stefano; Biancalana, Fabio

    2014-01-15

    We study analytically and numerically an optical analogue of Dirac solitons in binary waveguide arrays in the presence of Kerr nonlinearity. Pseudo-relativistic soliton solutions of the coupled-mode equations describing dynamics in the array are analytically derived. We demonstrate that with the found soliton solutions, the coupled mode equations can be converted into the nonlinear relativistic 1D Dirac equation. This paves the way for using binary waveguide arrays as a classical simulator of quantum nonlinear effects arising from the Dirac equation, something that is thought to be impossible to achieve in conventional (i.e. linear) quantum field theory. -- Highlights: •An optical analogue of Dirac solitons in nonlinear binary waveguide arrays is suggested. •Analytical solutions to pseudo-relativistic solitons are presented. •A correspondence of optical coupled-mode equations with the nonlinear relativistic Dirac equation is established.

  9. Isobaric Analogue States Studied in Mirrored Fragmentation and Knockout Reactions

    SciTech Connect

    Bentley, M.A.; Pritychenko, B.; Paterson,I.; Brown,J.R.; Taylor,M.J.; Digen,C.Aa.; Adrich,P.; Bazin,D.; Cook.J.M.; Gade,A.; Glasmacher,T.; McDaniel,S.; Ratkiewicz,A.; Siwek,K.; D.Weisshaar,D.; Pritychenko,B.; Lenzi,S.M.

    2010-05-21

    A Gamma-ray spectroscopic study of excited states of isobaric multiplets has been performed in recent years, with a view to gaining a quantitative understanding of energy differences between excited states in terms of a range of Coulomb and other isospin breaking phenomena. Recently, the experimental programme has been augmented by a study of isobaric analogue states of mirror nuclei populated in mirrored fragmentation reactions. In this presentation, recent results on the T = 3/2 analogue states in the T{sub z} = {+-} 3/2 mirror pair {sup 53}Ni/{sup 53}Mn will be summarised. In this work, further strong evidence is found for the need to include an anomalous isospin-breaking two-body matrix element for angular-momentum couplings of J = 2, in addition the expected Coulomb contribution, in order to account for the experimental data.

  10. Animal analogues for the study of dental and oral diseases.

    PubMed

    Levy, B M

    1980-01-01

    The usual laboratory animals, such as rats and hamsters, may not fit the criteria for an analogue of human periodontal disease, although they may be useful in the study of dental caries. Rats, hamsters, mice, guinea pigs and rabbits have been the animals of choice in studies relating nutritional deficiencies and excesses to the dental and oral tissues. Gerbils, dogs, cats, horses, cows and fowl are useful in the study of mineralized tissues of teeth and bones. Recently, primate analogues have been developed for the study of periodontal diseaes and dental caries, the two most important dental diseases afflicting man. The use of a wide variety of laboratory animals in basic dental research makes it timely to review some of the guidelines for the selection of specific animals for particular diseases.

  11. Analogue Transformations in Physics and their Application to Acoustics

    PubMed Central

    García-Meca, C.; Carloni, S.; Barceló, C.; Jannes, G.; Sánchez-Dehesa, J.; Martínez, A.

    2013-01-01

    Transformation optics has shaped up a revolutionary electromagnetic design paradigm, enabling scientists to build astonishing devices such as invisibility cloaks. Unfortunately, the application of transformation techniques to other branches of physics is often constrained by the structure of the field equations. We develop here a complete transformation method using the idea of analogue spacetimes. The method is general and could be considered as a new paradigm for controlling waves in different branches of physics, from acoustics in quantum fluids to graphene electronics. As an application, we derive an “analogue transformation acoustics” formalism that naturally allows the use of transformations mixing space and time or involving moving fluids, both of which were impossible with the standard approach. To demonstrate the power of our method, we give explicit designs of a dynamic compressor, a spacetime cloak for acoustic waves and a carpet cloak for a moving aircraft. PMID:23774575

  12. Alligator rivers analogue project an OECD/NEA international project

    SciTech Connect

    Duerden, P.; Airey, P.; Pescatore, C.

    1994-12-31

    The Koongarra uranium deposit in the Alligator Rivers Region of the Northern Territory of Australia was studied as a natural analogue of the far field behaviour of high level waste repositories following groundwater ingress. A number of mathematical modelling approaches were developed for processes as diverse as groundwater transport, host rock weathering, radionuclide sorption, evolution of the uranium dispersion fan and the distribution of uranium series nuclides between mineral assemblages in weathered host rock. Some of these models are relevant to performance assessment at the level of individual processes and subsystem performance. Through the project, new insights into the application of the natural analogue approach to the assessment of potential waste repository sites were obtained.

  13. Neurological Effects of Bisphenol A and its Analogues

    PubMed Central

    Inadera, Hidekuni

    2015-01-01

    The endocrine disrupting chemical bisphenol A (BPA) is widely used in the production of polycarbonate plastics and epoxy resins. The use of BPA-containing products in daily life makes exposure ubiquitous, and the potential human health risks of this chemical are a major public health concern. Although numerous in vitro and in vivo studies have been published on the effects of BPA on biological systems, there is controversy as to whether ordinary levels of exposure can have adverse effects in humans. However, the increasing incidence of developmental disorders is of concern, and accumulating evidence indicates that BPA has detrimental effects on neurological development. Other bisphenol analogues, used as substitutes for BPA, are also suspected of having a broad range of biological actions. The objective of this review is to summarize our current understanding of the neurobiological effects of BPA and its analogues, and to discuss preventive strategies from a public health perspective. PMID:26664253

  14. New Immunosuppressive Sphingoid Base and Ceramide Analogues in Wild Cordyceps

    PubMed Central

    Mi, Jia-Ning; Han, Yuwei; Xu, Yingqiong; Kou, Junping; Wang, Jing-Rong; Jiang, Zhi-Hong

    2016-01-01

    A comprehensive identification of sphingoid bases and ceramides in wild Cordyceps was performed by integrating a sequential chromatographic enrichment procedure and an UHPLC-ultrahigh definition-Q-TOF-MS based sphingolipidomic approach. A total of 43 sphingoid bases and 303 ceramides were identified from wild Cordyceps, including 12 new sphingoid base analogues and 159 new ceramide analogues based on high-resolution MS and MS/MS data, isotope distribution, matching with the comprehensive personal sphingolipid database, confirmation by sphingolipid standards and chromatographic retention time rule. The immunosuppressive bioassay results demonstrated that Cordyceps sphingoid base fraction exhibits more potent immunosuppressive activity than ceramide fraction, elucidating the immunosuppressive ingredients of wild Cordyceps. This study represented the most comprehensive identification of sphingoid bases and ceramides from a natural source. The findings of this study provided an insight into therapeutic application of wild Cordyceps. PMID:27966660

  15. New Immunosuppressive Sphingoid Base and Ceramide Analogues in Wild Cordyceps.

    PubMed

    Mi, Jia-Ning; Han, Yuwei; Xu, Yingqiong; Kou, Junping; Wang, Jing-Rong; Jiang, Zhi-Hong

    2016-12-14

    A comprehensive identification of sphingoid bases and ceramides in wild Cordyceps was performed by integrating a sequential chromatographic enrichment procedure and an UHPLC-ultrahigh definition-Q-TOF-MS based sphingolipidomic approach. A total of 43 sphingoid bases and 303 ceramides were identified from wild Cordyceps, including 12 new sphingoid base analogues and 159 new ceramide analogues based on high-resolution MS and MS/MS data, isotope distribution, matching with the comprehensive personal sphingolipid database, confirmation by sphingolipid standards and chromatographic retention time rule. The immunosuppressive bioassay results demonstrated that Cordyceps sphingoid base fraction exhibits more potent immunosuppressive activity than ceramide fraction, elucidating the immunosuppressive ingredients of wild Cordyceps. This study represented the most comprehensive identification of sphingoid bases and ceramides from a natural source. The findings of this study provided an insight into therapeutic application of wild Cordyceps.

  16. Synthesis of dehydroepiandrosterone analogues modified with phosphatidic acid moiety.

    PubMed

    Smuga, Damian A; Smuga, Małgorzata; Swizdor, Alina; Panek, Anna; Wawrzeńczyk, Czesław

    2010-12-12

    Dehydroepiandrosterone (DHEA) and its metabolite 7α-OH DHEA have many diverse physiological, biological and biochemical effects encompassing various cell types, tissues and organs. In in vitro studies, DHEA analogues have myriad biological actions, but in vivo, especially in oral administration, DHEA produces far more limited clinical effects. One of the possible solutions of this problem is conversion of DHEA to active analogues and/or its transformation into prodrug form. In this article, the studies on the conversion of DHEA and 7α-OH DHEA into their phosphatides by the phosphodiester approach are described. In this esterification, N,N-dicyclohexylcarbodiimide (DCC) was the most efficient coupling agent as well as p-toluenesulphonyl chloride (TsCl).

  17. Active postoperative acromegaly: sustained remission after discontinuation of somatostatin analogues

    PubMed Central

    Cardenas-Salas, Jersy

    2016-01-01

    Summary In patients with active acromegaly after pituitary surgery, somatostatin analogues are effective in controlling the disease and can even be curative in some cases. After treatment discontinuation, the likelihood of disease recurrence is high. However, a small subset of patients remains symptom-free after discontinuation, with normalized growth hormone (GH) and insulin-like growth factor (IGF1) levels. The characteristics of patients most likely to achieve sustained remission after treatment discontinuation are not well understood, although limited evidence suggests that sustained remission is more likely in patients with lower GH and IGF1 levels before treatment withdrawal, in those who respond well to low-dose treatment, in those without evidence of adenoma on an MRI scan and/or in patients who receive long-term treatment. In this report, we describe the case of a 56-year-old female patient treated with lanreotide Autogel for 11 years. Treatment was successfully discontinued, and the patient is currently disease-free on all relevant parameters (clinical, biochemical and tumour status). The successful outcome in this case adds to the small body of literature suggesting that some well-selected patients who receive long-term treatment with somatostatin analogues may achieve sustained remission. Learning points: The probability of disease recurrence is high after discontinuation of treatment with somatostatin analogues. Current data indicate that remission after treatment discontinuation may be more likely in patients with low GH and IGF1 levels before treatment withdrawal, in those who respond well to low-dose treatment, in those without evidence of adenoma on MRI, and/or in patients receiving prolonged treatment. This case report suggests that prolonged treatment with somatostatin analogues can be curative in carefully selected patients. PMID:27933171

  18. OptZyme: Computational Enzyme Redesign Using Transition State Analogues

    PubMed Central

    Grisewood, Matthew J.; Gifford, Nathanael P.; Pantazes, Robert J.; Li, Ye; Cirino, Patrick C.; Janik, Michael J.; Maranas, Costas D.

    2013-01-01

    OptZyme is a new computational procedure for designing improved enzymatic activity (i.e., kcat or kcat/KM) with a novel substrate. The key concept is to use transition state analogue compounds, which are known for many reactions, as proxies for the typically unknown transition state structures. Mutations that minimize the interaction energy of the enzyme with its transition state analogue, rather than with its substrate, are identified that lower the transition state formation energy barrier. Using Escherichia coli β-glucuronidase as a benchmark system, we confirm that KM correlates (R2 = 0.960) with the computed interaction energy between the enzyme and the para-nitrophenyl- β, D-glucuronide substrate, kcat/KM correlates (R2 = 0.864) with the interaction energy of the transition state analogue, 1,5-glucarolactone, and kcat correlates (R2 = 0.854) with a weighted combination of interaction energies with the substrate and transition state analogue. OptZyme is subsequently used to identify mutants with improved KM, kcat, and kcat/KM for a new substrate, para-nitrophenyl- β, D-galactoside. Differences between the three libraries reveal structural differences that underpin improving KM, kcat, or kcat/KM. Mutants predicted to enhance the activity for para-nitrophenyl- β, D-galactoside directly or indirectly create hydrogen bonds with the altered sugar ring conformation or its substituents, namely H162S, L361G, W549R, and N550S. PMID:24116038

  19. Synthesis of a platform to access bistramides and their analogues.

    PubMed

    Commandeur, Malgorzata; Commandeur, Claude; Cossy, Janine

    2011-11-18

    The platform C14-C40, which can be used to prepare bistramide C and 39-oxobistramide K, was synthesized in 19 steps with an overall yield of 6.2%. Furthermore, the chemoselective reduction of the ketone at C-39 was performed giving an easy access to bistramides A, B, D, K, and L. Finally, the versatility of the synthesis of the C14-C40 fragment can allow the preparation of a large variety of stereoisomers to produce bistramide analogues.

  20. Effect of lipophilicity on the pharmacokinetics of radiolabeled spiperone analogues

    SciTech Connect

    Moerlein, S.M.; Laufer, P.; Stocklin, G.

    1985-05-01

    Several radiolabeled analogues of the butyrophenone neuroleptic spiperone exhibit in vivo localization in D/sub 2/ receptor-rich areas of the brain. A series of N-alkylated spiperone analogues and the corresponding p-brominated compounds were synthesized to ascertain the optimum structure for labeling with /sup 18/F or /sup 75/Br. In vivo studies indicated that all analogues had D/sub 2/ receptor-binding affinity within the same order of magnitude (IC/sub 50/=2.6 nM for SP and 3.9 nM for BPSP), whereas the lipophilicity varied greatly (log P=2.7 for SP and 5.2 for BPSP). In vivo studies in the rat using the radiobrominated analogues were done using compounds labeled with n.c.a. /sup 77/Br via in-situ oxidation by dichloramine-T or H/sub 2/O/sub 2//CH/sub 3/COOH. Alkylation of BSP was found to decrease the striatum-to-cerebellum concentration at 6 hr from 8.2 for BSP to 5.2 for BPSP. Unexpectedly, the cerebral uptake did not increase with log P, the striatal concentration dropping from 390% MBC for BSP to 85% MBC for BPSP. This contrasts with previous results for SP and MSP, where the brain uptake increases slightly with log P. Increasing lipophilicity increases blood faster than brain concentrations, and it is concluded that whereas N-alkylation may be beneficial for /sup 18/F-labeld neuroleptics, non-alkylated spiperone is the optimum labeling substrate for /sup 75/Br.

  1. Bis(vinylenedithio)tetrathiafulvalene analogues of BEDT-TTF

    PubMed Central

    Demirtas, İlknur; Ozturk, Turan

    2015-01-01

    Summary This review aims to give an overview of the current status of our research on the synthesis of π-electron donor bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF, ET) analogues prepared from 1,8-diketones via a ring forming reaction. The new synthesized π-electron donors have vinyl moieties producing extended π-electron delocalization over the substituent phenyl rings at the peripheries. PMID:25977714

  2. Dimerization and DNA recognition rules of mithramycin and its analogues

    PubMed Central

    Weidenbach, Stevi; Hou, Caixia; Chen, Jhong-Min; Tsodikov, Oleg V.; Rohr, Jürgen

    2016-01-01

    The antineoplastic and antibiotic natural product mithramycin (MTM) is used against cancer-related hypercalcemia and, experimentally, against Ewing sarcoma and lung cancers. MTM exerts its cytotoxic effect by binding DNA as a divalent metal ion (Me2+)-coordinated dimer and disrupting the function of transcription factors. A precise molecular mechanism of action of MTM, needed to develop MTM analogues selective against desired transcription factors, is lacking. Although it is known that MTM binds G/C-rich DNA, the exact DNA recognition rules that would allow one to map MTM binding sites remain incompletely understood. Towards this goal, we quantitatively investigated dimerization of MTM and several of its analogues, MTM SDK (for Short side chain, DiKeto), MTM SA-Trp (for Short side chain and Acid), MTM SA-Ala, and a biosynthetic precursor premithramycin B (PreMTM B), and measured the binding affinities of these molecules to DNA oligomers of different sequences and structural forms at physiological salt concentrations. We show that MTM and its analogues form stable dimers even in the absence of DNA. All molecules, except for PreMTM B, can bind DNA with the following rank order of affinities (strong to weak): MTM = MTM SDK > MTM SA-Trp > MTM SA-Ala. An X(G/C)(G/C)X motif, where X is any base, is necessary and sufficient for MTM binding to DNA, without a strong dependence on DNA conformation. These recognition rules will aid in mapping MTM sites across different promoters towards development of MTM analogues as useful anticancer agents. PMID:26760230

  3. Synthesis of phosphonate and phostone analogues of ribose-1-phosphates

    PubMed Central

    Nasomjai, Pitak; Slawin, Alexandra M Z

    2009-01-01

    Summary The synthesis of phosphonate analogues of ribose-1-phosphate and 5-fluoro-5-deoxyribose-1-phosphate is described. Preparations of both the α- and β-phosphonate anomers are reported for the ribose and 5-fluoro-5-deoxyribose series and a synthesis of the corresponding cyclic phostones of each α-ribose is also reported. These compounds have been prepared as tools to probe the details of fluorometabolism in S. cattleya. PMID:19777136

  4. Novel ynamide structural analogues and their synthetic transformations

    PubMed Central

    Lu, Ting; Hsung, Richard P.

    2015-01-01

    This Highlight accounts for a recent phenomenon in which a series of novel ynamide structural analogues have emerged and caught the attention of the synthetic community. Preparations and reactions of these de novo ynamide variants are delineated here to demonstrate their accessibility as well as their reactivity. This Highlight should help reveal that these unique N-containing alkynes can become highly versatile building blocks in organic syntheses. PMID:26280027

  5. Pre-Clinical Testing of New Hydroxybutyrate Analogues

    DTIC Science & Technology

    2011-07-01

    the effects of DHB analogues to ascertain if they are longer-acting compounds than the parent compound. Although obtaining the first and only drug ...useful in the treatment of PD. Body of Work The goal of this study is to fully assess and compare the potency of compounds that are structurally...SARA 313: Carcinogenicity Classification (components present at 0.1% or more): none, unless listed below TSCA (US Toxic Substances Control Act

  6. Differential membrane fluidization by active and inactive cannabinoid analogues.

    PubMed

    Mavromoustakos, T; Papahatjis, D; Laggner, P

    2001-06-06

    The effects of the two cannabinomimetic drugs (-)-2-(6a,7,10,10a-tetrahydro-6,6,9-trimethyl-1-hydroxy-6H-dibenzo[b,d]pyranyl-2-(hexyl)-1,3-dithiolane (AMG-3) and its pharmacologically less active 1-methoxy analogue (AMG-18) on the thermotropic and structural properties of dipalmitoyl-sn-glycero-3-phosphorylcholine (DPPC) liposomes have been studied by X-ray diffraction and differential scanning calorimetry (DSC). DSC data revealed that the incorporation of the drugs affect differently the thermotropic properties of DPPC. The presence of the more active drug distinctly broadened and attenuated both the pretransition and main phase transition of DPPC bilayers, while the inactive analogue had only minor effects. Small and wide angle X-ray diffraction data showed that the two cannabinoids have different effects on the lipid phase structures and on the hydrocarbon chain packing. The pharmacologically active analogue, AMG-3, was found to efficiently fluidize domains of the lipids in the L(beta)' gel phase, and to perturb the regular multibilayer lattice. In the liquid crystalline L(alpha) phase, AMG-3 was also found to cause irregularities in packing, suggesting that the drug induces local curvature. At the same concentration, the inactive AMG-18 had only minor structural effects on the lipids. At about 10-fold or higher concentrations, AMG-18 was found to produce similar but still less pronounced effects in comparison to those observed by AMG-3. The dose-dependent, different thermotropic and structural effects by the two cannabinoid analogues suggest that these may be related to their biological activity.

  7. Evaluation of Anti-HIV-1 Mutagenic Nucleoside Analogues*

    PubMed Central

    Vivet-Boudou, Valérie; Isel, Catherine; El Safadi, Yazan; Smyth, Redmond P.; Laumond, Géraldine; Moog, Christiane; Paillart, Jean-Christophe; Marquet, Roland

    2015-01-01

    Because of their high mutation rates, RNA viruses and retroviruses replicate close to the threshold of viability. Their existence as quasi-species has pioneered the concept of “lethal mutagenesis” that prompted us to synthesize pyrimidine nucleoside analogues with antiviral activity in cell culture consistent with an accumulation of deleterious mutations in the HIV-1 genome. However, testing all potentially mutagenic compounds in cell-based assays is tedious and costly. Here, we describe two simple in vitro biophysical/biochemical assays that allow prediction of the mutagenic potential of deoxyribonucleoside analogues. The first assay compares the thermal stabilities of matched and mismatched base pairs in DNA duplexes containing or not the nucleoside analogues as follows. A promising candidate should display a small destabilization of the matched base pair compared with the natural nucleoside and the smallest gap possible between the stabilities of the matched and mismatched base pairs. From this assay, we predicted that two of our compounds, 5-hydroxymethyl-2′-deoxyuridine and 5-hydroxymethyl-2′-deoxycytidine, should be mutagenic. The second in vitro reverse transcription assay assesses DNA synthesis opposite nucleoside analogues inserted into a template strand and subsequent extension of the newly synthesized base pairs. Once again, only 5-hydroxymethyl-2′-deoxyuridine and 5-hydroxymethyl-2′-deoxycytidine are predicted to be efficient mutagens. The predictive potential of our fast and easy first line screens was confirmed by detailed analysis of the mutation spectrum induced by the compounds in cell culture because only compounds 5-hydroxymethyl-2′-deoxyuridine and 5-hydroxymethyl-2′-deoxycytidine were found to increase the mutation frequency by 3.1- and 3.4-fold, respectively. PMID:25398876

  8. Ungeremine and Its hemisynthesized analogues as bactericides against Flavobacterium columnare.

    PubMed

    Schrader, Kevin K; Avolio, Fabiana; Andolfi, Anna; Cimmino, Alessio; Evidente, Antonio

    2013-02-13

    The Gram-negative bacterium Flavobacterium columnare is the cause of columnaris disease, which can occur in channel catfish ( Ictalurus punctatus ). In a previous study, the betaine-type alkaloid ungeremine, 1, obtained from Pancratium maritimum L. was found to have strong antibacterial activity against F. columnare. In this study, analogues of 1 were evaluated using a rapid bioassay for activity against F. columnare to determine if the analogues might provide greater antibacterial activity and to determine structure-activity relationships of the test compounds. Several ungeremine analogues were prepared by hydrochlorination of the alkaloid and by selenium dioxide oxidation of both lycorine, 7, and pseudolycorine, 8, which yielded the isomer of ungeremine, 3, and zefbetaine, 4, respectively. The treatment of lycorine with phosphorus oxychloride allowed the synthesis of an anhydrolycorine lactam, 5, showing, with respect to 1, the deoxygenation and oxygenation of C-2 and C-7 of the C and B rings, respectively. The results of the structure-activity relationship studies showed that the aromatization of the C ring and the oxidation to an azomethine group of C-7 of the B ring are structural features important for antibacterial activity. In addition, the position of the oxygenation of the C ring as well as the presence of the 1,3-dioxole ring joined to the A ring of the pyrrolo[de]phenanthridine skeleton also plays a significant role in imparting antibacterial activity. On the basis of 24-h 50% inhibition concentration (IC(50)) results, ungeremine hydrochloride, 2, was similar in toxicity to 1, whereas 5 had the lowest activity. Analogue 2 is soluble in water, which may provide the benefit for use as an effective feed additive or therapeutant compared to ungeremine.

  9. Why are blue zhamanshinites blue? Liquid immiscibility in an impact melt

    NASA Technical Reports Server (NTRS)

    Zolensky, Michael E.; Koeberl, Christian

    1991-01-01

    A study of the cause of the coloration of blue zhamanshinites, which are glassy impact melt rocks from the Zhamanshin crater in the USSR are reported. It is found that the blue color results from Rayleigh scattering from spherical, 100 nm-diameter inclusions of a separate Ca-Fe-Mg-P-rich silicate glass. These observations can best be explained by the operation of liquid immiscibility in the zhamanshinite melt, and suggest that liquid immiscibility may have a more general role in impactite evolution.

  10. Natural analogue studies as supplements to biomineralization research

    SciTech Connect

    McNeil, M.B.

    1995-09-01

    Chemical reactions can alter the chemistry and crystal structure of solid objects over archeological or geological times, while preserving external physical shapes. The reactions resulting in these structures offer natural analogues to laboratory experiments in biomineralization and to biologically influenced alteration of nuclear waste packages, and thus, they offer the only available way of validating models that purport waste package behavior over archaeological or geological times. Potential uses of such analogues in the construction and validation of hypothetical mechanisms of microbiological corrosion and biomineralization are reviewed. Evidence from such analogues suggests that biofilms can control materials alteration in ways usually overlooked. The newly hypothesized mechanisms involve control by biofilms of the cation flow near the solid surface and offer plausible mechanisms for the formation of mixed-cation minerals under conditions that would lead to dealloying in abiotic experiments; they also account for the formation of unusual minerals [such as posnjakite, Cu{sub 4}SO{sub 4}(OH){sub 6{center_dot}}H{sub 2}O] and mineral morphologies unusual in corrosion [malachite, Cu{sub 2}CO{sub 3}(OH){sub 2}, rarely forms botryoidally under corrosion conditions and its occasional presence on archaeological objects that appear to have undergone microbiological corrosion may be related to biofilm phenomena].

  11. Analogue Investigations into Magma-Cryosphere Interactions on Mars

    NASA Astrophysics Data System (ADS)

    Tyson, S.; Wilson, L.; Lane, S. J.; Airey, M. W.; Gilbert, J. S.

    2011-12-01

    Many landforms and morphological features thought to have resulted from magma-cryosphere interactions have been identified on Mars. However, few experimental studies have been conducted to investigate the physical and thermal changes that should occur in the subsurface during these interactions. This project aims to begin to address this by conducting a series of laboratory analogue experiments. We introduce a heat source into a block of analogue cryosphere material (a carefully-prepared mixture of solid grains and ice) and record the thermal development within the block using thermocouples. We use these measurements to interpret the physical activity within the block, such as when and where phase changes occur, what sequence of shapes the developing melt region takes, and the extent of convection of any fluid phase H20. Blocks are also dissected after each run and documented photographically to record any physical movement of grains. Results will be used to constrain variables within a heat flow model that we are developing. This model will then be applied to the interpretation of landforms on Mars to help determine what set of processes could have realistically occurred during their formation. A second series of experiments will investigate surface morphological changes on the cryosphere analogue blocks. Resultant morphologies will be recorded and compared with existing martian landforms to again provide insight into formation processes.

  12. The UVB1 Vitamin D analogue inhibits colorectal carcinoma progression.

    PubMed

    Ferronato, María Julia; Alonso, Eliana Noelia; Gandini, Norberto Ariel; Fermento, María Eugenia; Villegas, María Emilia; Quevedo, Mario Alfredo; Arévalo, Julián; López Romero, Alejandro; Rivadulla, Marcos Lois; Gómez, Generosa; Fall, Yagamare; Facchinetti, María Marta; Curino, Alejandro Carlos

    2016-10-01

    Vitamin D has been shown to display a wide variety of antitumour effects, but their therapeutic use is limited by its severe side effects. We have designed and synthesized a Gemini vitamin D analogue of calcitriol (UVB1) which has shown to display antineoplastic effects on different cancer cell lines without causing hypercalcemia. The aim of this work has been to investigate, by employing in silico, in vitro, and in vivo assays, whether UVB1 inhibits human colorectal carcinoma progression. We demonstrated that UVB1 induces apoptotic cell death and retards cellular migration and invasion of HCT116 colorectal carcinoma cells. Moreover, the analogue reduced the tumour volume in vivo, and modulated the expression of Bax, E-cadherin and nuclear β-catenin in tumour animal tissues without producing toxic effects. In silico analysis showed that UVB1 exhibits greater affinity for the ligand binding domain of vitamin D receptor than calcitriol, and that several characteristics in the three-dimensional conformation of VDR may influence the biological effects. These results demonstrate that the Gemini vitamin D analogue affects the growth of the colorectal cancer and suggest that UVB1 is a potential chemotherapeutic agent for treatment of this disease.

  13. Design and synthesis of biotin analogues reversibly binding with streptavidin.

    PubMed

    Yamamoto, Tomohiro; Aoki, Kiyoshi; Sugiyama, Akira; Doi, Hirofumi; Kodama, Tatsuhiko; Shimizu, Yohei; Kanai, Motomu

    2015-04-01

    Two new biotin analogues, biotin carbonate 5 and biotin carbamate 6, have been synthesized. These molecules were designed to reversibly bind with streptavidin by replacing the hydrogen-bond donor NH group(s) of biotin's cyclic urea moiety with oxygen. Biotin carbonate 5 was synthesized from L-arabinose (7), which furnishes the desired stereochemistry at the 3,4-cis-dihydroxy groups, in 11% overall yield (over 10 steps). Synthesis of biotin carbamate 6 was accomplished from L-cysteine-derived chiral aldehyde 33 in 11% overall yield (over 7 steps). Surface plasmon resonance analysis of water-soluble biotin carbonate analogue 46 and biotin carbamate analogue 47 revealed that KD values of these compounds for binding to streptavidin were 6.7×10(-6)  M and 1.7×10(-10)  M, respectively. These values were remarkably greater than that of biotin (KD =10(-15)  M), and thus indicate the importance of the nitrogen atoms for the strong binding between biotin and streptavidin.

  14. Transdermal delivery of a melanotropic peptide hormone analogue

    SciTech Connect

    Dawson, B.V.; Hadley, M.E.; Kreutzfeld, K.; Dorr, R.T.; Hruby, V.J.; Al-Obeidi, F.; Don, S.

    1988-01-01

    We previously reported that topical application of (Nl3/sup 4/,D-Phe/sup 7/)alpha-MSH, a superpotent analogue of alpha-melanocyte stimulating hormone, to mice induces a darkening of follicular melanocytes throughout the skin. We now report that the melanotropin analogue can be delivered across mouse but not rat skin in an in vitro model system. Passage of the analogue from the topically applied vehicle (polyethylene glycol) across the skin into a subcutaneous receiving vessel was demonstrated by both bioassay as well as by radioimmunoassay. The bioassay data demonstrate that percutaneous absorption of the melanotropin did not result in loss of biological activity of the peptide. The differential penetration of the peptide across rodent skin reveals that one cannot predict percutaneous absorption of a substance across the stratum corneum from studies on a single species. The present results are the first to demonstrate, by direct quantitative measurements, that a bioactive peptide can be delivered across the vertebrate integument in vitro. These studies point out the potential of a topically applied melanotropin for tanning of the skin and possibly for treatment of certain hypopigmentary disorders.

  15. Contact zones and hydrothermal systems as analogues to repository conditions

    SciTech Connect

    Wollenberg, H.A.; Flexser, S.

    1984-10-01

    Radioactive waste isolation efforts in the US are currently focused on examining basalt, tuff, salt, and crystalline rock as candidate rock types to encompass waste repositories. As analogues to near-field conditions, the distributions of radio- and trace-elements have been examined across contacts between these rocks and dikes and stocks that have intruded them. The intensive study of the Stripa quartz monzonite has also offered the opportunity to observe the distribution of uranium and its daughters in groundwater and its relationship to U associated with fracture-filling and alteration minerals. Investigations of intrusive contact zones to date have included (1) a tertiary stock into Precambrian gneiss, (2) a stock into ash flow tuff, (3) a rhyodacite dike into Columbia River basalt, and (4) a kimberlite dike into salt. With respect to temperature and pressure, these contact zones may be considered "worst-case scenario" analogues. Results indicate that there has been no appreciable migration of radioelements from the more radioactive intrusives into the less radioactive country rocks, either in response to the intrusions or in the fracture-controlled hydrological systems that developed following emplacement. In many cases, the radioelements are locked up in accessory minerals, suggesting that artificial analogues to these would make ideal waste forms. Emphasis should now shift to examination of active hydrothermal systems, studying the distribution of key elements in water, fractures, and alteration minerals under pressure and temperature conditions most similar to those expected in the near-field environment of a repository. 14 refs.

  16. THE PENA BLANCA NATURAL ANALOGUE PERFORMANCE ASSESSMENT MODEL

    SciTech Connect

    G. Saulnier and W. Statham

    2006-04-16

    The Nopal I uranium mine in the Sierra Pena Blanca, Chihuahua, Mexico serves as a natural analogue to the Yucca Mountain repository. The Pena Blanca Natural Analogue Performance Assessment Model simulates the mobilization and transport of radionuclides that are released from the mine and transported to the saturated zone. The Pena Blanca Natural Analogue Performance Assessment Model uses probabilistic simulations of hydrogeologic processes that are analogous to the processes that occur at the Yucca Mountain site. The Nopal I uranium deposit lies in fractured, welded, and altered rhyolitic ash-flow tuffs that overlie carbonate rocks, a setting analogous to the geologic formations at the Yucca Mountain site. The Nopal I mine site has the following analogous characteristics as compared to the Yucca Mountain repository site: (1) Analogous source--UO{sub 2} uranium ore deposit = spent nuclear fuel in the repository; (2) Analogous geology--(i.e. fractured, welded, and altered rhyolitic ash-flow tuffs); (3) Analogous climate--Semiarid to arid; (4) Analogous setting--Volcanic tuffs overlie carbonate rocks; and (5) Analogous geochemistry--Oxidizing conditions Analogous hydrogeology: The ore deposit lies in the unsaturated zone above the water table.

  17. An adenosine nucleoside analogue NITD008 inhibits EV71 proliferation.

    PubMed

    Shang, Luqing; Wang, Yaxin; Qing, Jie; Shu, Bo; Cao, Lin; Lou, Zhiyong; Gong, Peng; Sun, Yuna; Yin, Zheng

    2014-12-01

    Enterovirus 71 (EV71), one of the major causative agents of Hand-Foot-Mouth Disease (HFMD), causes severe pandemics and hundreds of deaths in the Asia-Pacific region annually and is an enormous public health threat. However, effective therapeutic antiviral drugs against EV71 are rare. Nucleoside analogues have been successfully used in the clinic for the treatment of various viral infections. We evaluated a total of 27 nucleoside analogues and discovered that an adenosine nucleoside analogue NITD008, which has been reported to be an antiviral reagent that specifically inhibits flaviviruses, effectively suppressed the propagation of different strains of EV71 in RD, 293T and Vero cells with a relatively high selectivity index. Triphosphorylated NITD008 (ppp-NITD008) functions as a chain terminator to directly inhibit the RNA-dependent RNA polymerase activity of EV71, and it does not affect the EV71 VPg uridylylation process. A significant synergistic anti-EV71 effect of NITD008 with rupintrivir (AG7088) (a protease inhibitor) was documented, supporting the potential combination therapy of NITD008 with other inhibitors for the treatment of EV71 infections.

  18. Stereochemical Assignment of Strigolactone Analogues Confirms Their Selective Biological Activity.

    PubMed

    Artuso, Emma; Ghibaudi, Elena; Lace, Beatrice; Marabello, Domenica; Vinciguerra, Daniele; Lombardi, Chiara; Koltai, Hinanit; Kapulnik, Yoram; Novero, Mara; Occhiato, Ernesto G; Scarpi, Dina; Parisotto, Stefano; Deagostino, Annamaria; Venturello, Paolo; Mayzlish-Gati, Einav; Bier, Ariel; Prandi, Cristina

    2015-11-25

    Strigolactones (SLs) are new plant hormones with various developmental functions. They are also soil signaling chemicals that are required for establishing beneficial mycorrhizal plant/fungus symbiosis. In addition, SLs play an essential role in inducing seed germination in root-parasitic weeds, which are one of the seven most serious biological threats to food security. There are around 20 natural SLs that are produced by plants in very low quantities. Therefore, most of the knowledge on SL signal transduction and associated molecular events is based on the application of synthetic analogues. Stereochemistry plays a crucial role in the structure-activity relationship of SLs, as compounds with an unnatural D-ring configuration may induce biological effects that are unrelated to SLs. We have synthesized a series of strigolactone analogues, whose absolute configuration has been elucidated and related with their biological activity, thus confirming the high specificity of the response. Analogues bearing the R-configured butenolide moiety showed enhanced biological activity, which highlights the importance of this stereochemical motif.

  19. TREATMENT OF TYPE 2 DIABETES WITH BIPHASIC INSULIN ANALOGUES

    PubMed Central

    Rizvi, Ali A.

    2016-01-01

    The majority of patients with Type 2 diabetes require insulin therapy for treating hyperglycaemia. There are several regimens available for insulin initiation and maintenance. Insulin analogues have been developed to mimic normal physiology as closely as possible. Biphasic analogues can target both fasting and postprandial hyperglycaemia, with the added advantage of being premixed and thus convenient for the patient. A practical and feasible option is to initiate insulin with one or more biphasic preparations at mealtimes, thus providing both basal and prandial coverage. Individual titration of dose and frequency of daily injections with biphasic insulin preparations has the potential for improving glycaemic control with a high degree of patient acceptance. Drawbacks include a more rigid regimen, a relative lack of flexibility, and a somewhat higher degree of glycaemic variability and hypoglycaemia when compared to multiple daily basal-bolus injections. Awareness of the advantages and limitations of biphasic insulin analogues can assist clinicians in their appropriate use for the treatment of patients with Type 2 diabetes. PMID:27918600

  20. Do film soundtracks contain nonlinear analogues to influence emotion?

    PubMed Central

    Blumstein, Daniel T.; Davitian, Richard; Kaye, Peter D.

    2010-01-01

    A variety of vertebrates produce nonlinear vocalizations when they are under duress. By their very nature, vocalizations containing nonlinearities may sound harsh and are somewhat unpredictable; observations that are consistent with them being particularly evocative to those hearing them. We tested the hypothesis that humans capitalize on this seemingly widespread vertebrate response by creating nonlinear analogues in film soundtracks to evoke particular emotions. We used lists of highly regarded films to generate a set of highly ranked action/adventure, dramatic, horror and war films. We then scored the presence of a variety of nonlinear analogues in these film soundtracks. Dramatic films suppressed noise of all types, contained more abrupt frequency transitions and musical sidebands, and fewer noisy screams than expected. Horror films suppressed abrupt frequency transitions and musical sidebands, but had more non-musical sidebands, and noisy screams than expected. Adventure films had more male screams than expected. Together, our results suggest that film-makers manipulate sounds to create nonlinear analogues in order to manipulate our emotional responses. PMID:20504815

  1. Do film soundtracks contain nonlinear analogues to influence emotion?

    PubMed

    Blumstein, Daniel T; Davitian, Richard; Kaye, Peter D

    2010-12-23

    A variety of vertebrates produce nonlinear vocalizations when they are under duress. By their very nature, vocalizations containing nonlinearities may sound harsh and are somewhat unpredictable; observations that are consistent with them being particularly evocative to those hearing them. We tested the hypothesis that humans capitalize on this seemingly widespread vertebrate response by creating nonlinear analogues in film soundtracks to evoke particular emotions. We used lists of highly regarded films to generate a set of highly ranked action/adventure, dramatic, horror and war films. We then scored the presence of a variety of nonlinear analogues in these film soundtracks. Dramatic films suppressed noise of all types, contained more abrupt frequency transitions and musical sidebands, and fewer noisy screams than expected. Horror films suppressed abrupt frequency transitions and musical sidebands, but had more non-musical sidebands, and noisy screams than expected. Adventure films had more male screams than expected. Together, our results suggest that film-makers manipulate sounds to create nonlinear analogues in order to manipulate our emotional responses.

  2. Noble gas encapsulation: clathrate hydrates and their HF doped analogues.

    PubMed

    Mondal, Sukanta; Chattaraj, Pratim Kumar

    2014-09-07

    The significance of clathrate hydrates lies in their ability to encapsulate a vast range of inert gases. Although the natural abundance of a few noble gases (Kr and Xe) is poor their hydrates are generally abundant. It has already been reported that HF doping enhances the stability of hydrogen hydrates and methane hydrates, which prompted us to perform a model study on helium, neon and argon hydrates with their HF doped analogues. For this purpose 5(12), 5(12)6(8) and their HF doped analogues are taken as the model clathrate hydrates, which are among the building blocks of sI, sII and sH types of clathrate hydrate crystals. We use the dispersion corrected and gradient corrected hybrid density functional theory for the calculation of thermodynamic parameters as well as conceptual density functional theory based reactivity descriptors. The method of the ab initio molecular dynamics (AIMD) simulation is used through atom centered density matrix propagation (ADMP) techniques to envisage the structural behaviour of different noble gas hydrates on a 500 fs timescale. Electron density analysis is carried out to understand the nature of Ng-OH2, Ng-FH and Ng-Ng interactions. The current results noticeably demonstrate that the noble gas (He, Ne, and Ar) encapsulation ability of 5(12), 5(12)6(8) and their HF doped analogues is thermodynamically favourable.

  3. Spin Alignment in Analogues of The Local Sheet

    NASA Astrophysics Data System (ADS)

    Conidis, George J.

    2016-10-01

    Tidal torque theory and simulations of large scale structure predict spin vectors of massive galaxies should be coplanar with sheets in the cosmic web. Recently demonstrated, the giants (K s <= -22.5 mag) in the Local Volume beyond the Local Sheet have spin vectors directed close to the plane of the Local Supercluster, supporting the predictions of Tidal Torque Theory. However, the giants in the Local Sheet encircling the Local Group display a distinctly different arrangement, suggesting that the mass asymmetry of the Local Group or its progenitor torqued them from their primordial spin directions. To investigate the origin of the spin alignment of giants locally, analogues of the Local Sheet were identified in the SDSS DR9. Similar to the Local Sheet, analogues have an interacting pair of disk galaxies isolated from the remaining sheet members. Modified sheets in which there is no interacting pair of disk galaxies were identified as a control sample. Galaxies in face-on control sheets do not display axis ratios predominantly weighted toward low values, contrary to the expectation of tidal torque theory. For face-on and edge-on sheets, the distribution of axis ratios for galaxies in analogues is distinct from that in controls with a confidence of 97.6% & 96.9%, respectively. This corroborates the hypothesis that an interacting pair can affect spin directions of neighbouring galaxies.

  4. Four-quadrant analogue multiplier using operational amplifier

    NASA Astrophysics Data System (ADS)

    Riewruja, Vanchai; Rerkratn, Apinai

    2011-04-01

    A method to realise a four-quadrant analogue multiplier using general-purpose operational amplifiers (opamps) as only the active elements is described in this article. The realisation method is based on the quarter-square technique, which utilises the inherent square-law characteristic of class AB output stage of the opamp. The multiplier can be achieved from the proposed structure with using either bipolar or complementary metal-oxide-semiconductor (CMOS) opamps. The operation principle of the proposed multiplier has been confirmed by PSPICE analogue simulation program. Simulation results reveal that the principle of proposed scheme provides an adequate performance for a four-quadrant analogue multiplier. Experimental implementations of the proposed multiplier using bipolar and CMOS opamps are performed to verify the circuit performances. Measured results of the experimental proposed schemes based on the use of bipolar and CMOS opamps with supply voltage ±2.4 V show the worst-case relative errors of 0.32% and 0.47%, and the total harmonic distortions of 0.47% and 0.98%, respectively.

  5. Mammalian folylpoly-. gamma. -glutamate synthetase. 3. Specificity for folate analogues

    SciTech Connect

    George, S.; Cichowicz, D.J.; Shane, B.

    1987-01-27

    A variety of folate analogues were synthesized to explore the specificity of the folate binding site of hog liver folypolyglutamate synthetase and the requirements for catalysis. Modifications of the internal and terminal glutamate moieties of folate cause large drops in on rates and/or affinity for the protein. The only exceptions are glutamine, homocysteate, and ornithine analogues, indicating a less stringent specificity around the delta-carbon of glutamate. It is proposed that initial folate binding to the enzyme involves low-affinity interactions at a pterin and a glutamate site and that the first glutamate bound is the internal residue adjacent to the benzoyl group. Processive movement of the polyglutamate chain through the glutamate site and a possible conformational change in the protein when the terminal residue is bound would result in tight binding and would position the ..gamma..-carboxyl of the terminal glutamate in the correct position for catalysis. The 4-amino substitution of folate increases the on rate for monoglutamate derivatives but severely impairs catalysis with diglutamate derivatives. Pteroylornithine derivatives are the first potent and specific inhibitors of folylpolyglutamate synthetase to be identified and may act as analogues of reaction intermediates. Other folate derivatives with tetrahedral chemistry replacing the peptide bond, such as pteroyl-..gamma..-glutamyl-(psi,CH/sub 2/-NH)-glutamate, retain affinity for the protein but are considerably less effective inhibitors than the ornithine derivatives. Enzyme activity was assayed using (/sup 14/C)glutamate.

  6. Bilateral Choroidal Metastases from Endobronchial Carcinoid Treated with Somatostatin Analogues

    PubMed Central

    De Bruyn, Deborah; Lamont, Jan; Vanderstraeten, Erik; Van Belle, Simon; Platteau, Elise; De Zaeytijd, Julie; Hoornaert, Kristien P.

    2016-01-01

    Objective: To describe a patient with bilateral multifocal choroidal metastases from an endobronchial carcinoid treated with a somatostatin analogue. Method: A 60-year-old woman presenting with photopsia in the left eye underwent an extensive ophthalmic examination, including fluorescein angiography, OCT and ultrasound. Results: Fundoscopy revealed a small retinal tear in the left eye, for which she received laser treatment. In addition, choroidal masses were detected in both eyes. Her medical history of a pneumectomy for a bronchial carcinoid six years earlier together with recent elevated chromogranin A blood levels prompted a diagnosis of choroidal metastases. Subsequently, a Gallium-68 DOTANOC positron emitting tomography/computer tomography scan revealed a spinal cord metastasis and mediastinal as well as mesenterial lymph node invasion. Systemic treatment with Sandostatin®, a somatostatin analogue was started. Up until two years after the initial presentation and treatment, these choroidal lesions remained stable without any signs of growth. Conclusion: Endobronchial carcinoid tumors have an indolent nature and long-term follow-up is recommended for early detection of metastases. Although treatment with somatostatin analogues rarely induces complete tumor regression, tumor stabilization and prevention of symptoms related to hormone secretion is achieved. This well-tolerated systemic treatment provides a worthy alternative treatment for choroidal metastasis compared to classic radiotherapy without any risk of radiation or laser-related visual loss. PMID:27843513

  7. NMDA potentiation by visible light in the presence of a fluorescent neurosteroid analogue.

    PubMed

    Eisenman, Lawrence N; Shu, Hong-Jin; Wang, Cunde; Aizenman, Elias; Covey, Douglas F; Zorumski, Charles F; Mennerick, Steven

    2009-06-15

    N-Methyl-D-aspartate (NMDA) receptors are widely studied because of their importance in synaptic plasticity and excitotoxic cell death. Here we report a novel method of potentiating NMDA receptors with fluorescence excited by blue (480 nm) light. In the presence of 300 nM of a (7-nitro-2,1,3-benzoxadiazol-4-yl) amino (NBD)-tagged neuroactive steroid carrier C2-NBD-(3alpha,5alpha)-3-hydroxypregnan-20-one (C2-NBD 3alpha5alphaP), responses of cultured hippocampal neurons to 10 microM NMDA were potentiated to 219.2 +/- 9.2% of the baseline response (100%) by a 30 s exposure to 480 nm light. The potentiation decayed back to baseline with a time constant of 80.6 s. Responses to 1 microM and 100 microM NMDA were potentiated to 147.9 +/- 9.6% and 174.1 +/- 15.6% of baseline, respectively, suggesting that visible-light potentiation is relatively insensitive to NMDA concentration. Peak autaptic NMDA responses were potentiated to 178.9 +/- 22.4% of baseline. Similar potentiation was seen with 10 microM NBD-lysine, suggesting that visible-light potentiation is not a steroid effect. Potentiation was also seen with a steroid analogue in which the NBD was replaced with fluorescein, suggesting that NBD is not the only fluorophore capable of supporting visible-light potentiation. UV light and redox potentiation of NMDA receptors largely occluded subsequent blue light potentiation (127.7 +/- 7.4% and 120.2 +/- 6.2% of baseline, respectively). The NR1a(C744A,C798A) mutant that is insensitive to redox and UV potentiation was also largely unaffected by visible-light potentiation (135.0 +/- 10.0% of baseline). Finally, we found that the singlet oxygen scavenger furfuryl alcohol decreased visible-light potentiation. Collectively, these data suggest that visible-light potentiation of NMDA receptors by fluorescence excitation shares mechanisms with UV and redox potentiation and may involve singlet oxygen production.

  8. MOCK OBSERVATIONS OF BLUE STRAGGLERS IN GLOBULAR CLUSTER MODELS

    SciTech Connect

    Sills, Alison; Glebbeek, Evert; Chatterjee, Sourav; Rasio, Frederic A. E-mail: e.glebbeek@astro.ru.nl E-mail: rasio@northwestern.edu

    2013-11-10

    We created artificial color-magnitude diagrams of Monte Carlo dynamical models of globular clusters and then used observational methods to determine the number of blue stragglers in those clusters. We compared these blue stragglers to various cluster properties, mimicking work that has been done for blue stragglers in Milky Way globular clusters to determine the dominant formation mechanism(s) of this unusual stellar population. We find that a mass-based prescription for selecting blue stragglers will select approximately twice as many blue stragglers than a selection criterion that was developed for observations of real clusters. However, the two numbers of blue stragglers are well-correlated, so either selection criterion can be used to characterize the blue straggler population of a cluster. We confirm previous results that the simplified prescription for the evolution of a collision or merger product in the BSE code overestimates their lifetimes. We show that our model blue stragglers follow similar trends with cluster properties (core mass, binary fraction, total mass, collision rate) as the true Milky Way blue stragglers as long as we restrict ourselves to model clusters with an initial binary fraction higher than 5%. We also show that, in contrast to earlier work, the number of blue stragglers in the cluster core does have a weak dependence on the collisional parameter Γ in both our models and in Milky Way globular clusters.

  9. Blue, green, orange, and red upconversion laser

    DOEpatents

    Xie, P.; Gosnell, T.R.

    1998-09-08

    A laser is disclosed for outputting visible light at the wavelengths of blue, green, orange and red light. This is accomplished through the doping of a substrate, such as an optical fiber or waveguide, with Pr{sup 3+} ions and Yb{sup 3+} ions. A light pump such as a diode laser is used to excite these ions into energy states which will produce lasing at the desired wavelengths. Tuning elements such as prisms and gratings can be employed to select desired wavelengths for output. 11 figs.

  10. Blue, green, orange, and red upconversion laser

    DOEpatents

    Xie, Ping; Gosnell, Timothy R.

    1998-01-01

    A laser for outputting visible light at the wavelengths of blue, green, orange and red light. This is accomplished through the doping of a substrate, such as an optical fiber or waveguide, with Pr.sup.3+ ions and Yb.sup.3+ ions. A light pump such as a diode laser is used to excite these ions into energy states which will produce lasing at the desired wavelengths. Tuning elements such as prisms and gratings can be employed to select desired wavelengths for output.

  11. Maya Blue Paint: An Ancient Nanostructured Material

    PubMed

    Jose-Yacaman; Rendon; Arenas; Serra Puche MC

    1996-07-12

    Maya blue paint was often used in Mesoamerica. The origin of its color and its resistance to acids and biocorrosion have not been fully understood. High-resolution transmission electron microscopy, electron energy loss spectroscopy, and x-ray microanalysis studies of authentic samples show that palygorskite crystals in the paint form a superlattice that probably occurs as a result of mixing with indigo molecules. An amorphous silicate substrate contains inclusions of metal nanoparticles encapsulated in the substrate and oxide nanoparticles on the surface. The beautiful tone of the color is obtained only when both the particles and the superlattice are present.

  12. The curious conversion of Empire Blue Cross.

    PubMed

    Robinson, James C

    2003-01-01

    The for-profit conversion of Empire Blue Cross in New York challenges the case law and conventional policy wisdom that financial assets from formerly nonprofit organizations should be used to endow independent charitable foundations. The appropriation of Empire's assets by state government itself, and their subsequent deployment to subsidize health care institutions and repay political obligations, changes the conversion process from one that pits nonprofits against for-profits to one that pits private, nonprofit organizations against public-sector programs in the competition for new financial resources.

  13. Measuring star formation rates in blue galaxies

    NASA Technical Reports Server (NTRS)

    Gallagher, John S., III; Hunter, Deidre A.

    1987-01-01

    The problems associated with measurements of star formation rates in galaxies are briefly reviewed, and specific models are presented for determinations of current star formation rates from H alpha and Far Infrared (FIR) luminosities. The models are applied to a sample of optically blue irregular galaxies, and the results are discussed in terms of star forming histories. It appears likely that typical irregular galaxies are forming stars at nearly constant rates, although a few examples of systems with enhanced star forming activity are found among HII regions and luminous irregular galaxies.

  14. Blue Marble Space Institute essay contest

    NASA Astrophysics Data System (ADS)

    Wendel, JoAnna

    2014-04-01

    The Blue Marble Space Institute of Science, based in Seattle, Wash., is inviting college students to participate in its essay contest. Essays need to address the question, "In the next 100 years, how can human civilization prepare for the long-term changes to the Earth system that will occur over the coming millennium?" According to the institute, the purpose of the contest is "to stimulate creative thinking relating to space exploration and global issues by exploring how changes in the Earth system will affect humanity's future."

  15. Photometric monitoring of Luminous Blue Variables

    NASA Astrophysics Data System (ADS)

    Buemi, Carla; Distefano, Elisa; Leto, Paolo; Schillirò, Francesco; Trigilio, Corrado; Umana, Grazia; Bernabei, Stefano; Cutispoto, Giuseppe; Messina, Sergio

    2011-01-01

    We present some preliminary results from our program of intensive near-infrared photometric monitoring of a sample of confirmed and candidate Luminous Blue Variables (LBVs) conducted from 2008 to 2010. Clear long-term variability has been observed for Wray 17-96 and V481 Sct, with overall brightness variation greater than 1 mag in the J band. Other sources, such as LBV 1806-20 showed detectable variability with amplitudes of few tenths of a magnitude with a time-scale of about 60 days.

  16. Past and present of analogue modelling, and its future trend

    NASA Astrophysics Data System (ADS)

    Koyi, Hemin

    2015-04-01

    Since Hull (1815) published his article on modelling, analogue modelling has expanded to simulate both a wider range of tectonic regimes and target more challenging set-ups, and has become an integrated part of the fields of tectonics and structural geology. Establishment of new laboratories testifies for the increased attention the technique receives. The ties between modellers and field geoscientists have become stronger with the focus being on understanding the parameters that govern the evolution of a tectonic regime and the processes that dominate it. Since the first sand castle was built with damp sand on a beach, sand has proven to be an appropriate material analogue. Even though granular materials is the most widely used analogue material, new materials are also (re)introduced as rock analogues. Emphasis has been on more precise measurements of the mechanical properties of the materials and on minimizing the preparation effects, which have a great impact on scaling, interpretations and benchmarking. The analytical technique used to quantify model results has also seen a great deal of improvement. In addition to X-ray tomography used to visualise internal structures of models, new techniques (e.g. PIV, high-resolution laser scanning, and interferometry) have enabled monitoring kinematics with a higher precision. Benchmarking exercises have given modelling an additional checking tool by outlining, in addition to the rheology of the modelling materials, the impact of different preparation approaches, the effect of boundary conditions, and the human factor on model results. However, despite the different approaches and deformation rigs, results of models of different tectonic laboratories have shown a great deal of similarities. Even with the introduction of more sophisticated numerical codes and usage of more powerful computers which enable the simulation of more challenging material properties and combinations of those, and 3D model set-up, analogue modelling

  17. THE PENA BLANCA NATURAL ANALOGUE PERFORMANCE ASSESSMENT MODEL

    SciTech Connect

    G.J. Saulnier Jr; W. Statham

    2006-03-10

    The Nopal I uranium mine in the Sierra Pena Blanca, Chihuahua, Mexico serves as a natural analogue to the Yucca Mountain repository. The Pena Blanca Natural Analogue Performance Assessment Model simulates the mobilization and transport of radionuclides that are released from the mine and transported to the saturated zone. the Pena Blanca Natural Analogue Model uses probabilistic simulations of hydrogeologic processes that are analogous to the processes that occur at the Yucca Mountain site. The Nopal I uranium deposit lies in fractured, welded, and altered rhyolitic ash flow tuffs that overlie carbonate rocks, a setting analogous to the geologic formations at the Yucca Mountain site. The Nopal I mine site has the following characteristics as compared to the Yucca Mountain repository site. (1) Analogous source: UO{sub 2} uranium ore deposit = spent nuclear fuel in the repository; (2) Analogous geologic setting: fractured, welded, and altered rhyolitic ash flow tuffs overlying carbonate rocks; (3) Analogous climate: Semiarid to arid; (4) Analogous geochemistry: Oxidizing conditions; and (5) Analogous hydrogeology: The ore deposit lies in the unsaturated zone above the water table. The Nopal I deposit is approximately 8 {+-} 0.5 million years old and has been exposed to oxidizing conditions during the last 3.2 to 3.4 million years. The Pena Blanca Natural Analogue Model considers that the uranium oxide and uranium silicates in the ore deposit were originally analogous to uranium-oxide spent nuclear fuel. The Pena Blanca site has been characterized using field and laboratory investigations of its fault and fracture distribution, mineralogy, fracture fillings, seepage into the mine adits, regional hydrology, and mineralization that shows the extent of radionuclide migration. Three boreholes were drilled at the Nopal I mine site in 2003 and these boreholes have provided samples for lithologic characterization, water-level measurements, and water samples for laboratory

  18. Interglacial analogues of the Holocene and its natural near future

    NASA Astrophysics Data System (ADS)

    Yin, Qiuzhen; Berger, André

    2015-07-01

    In an attempt to find potential interglacial analogues of our present interglacial and its natural future, five interglacials (MIS-1, 5, 9, 11 and 19) are studied in terms of their astronomical characteristics, greenhouse gases concentration and climate simulated using both snapshot and transient experiments. Transient simulations covering a full range of obliquity, precession and eccentricity allow to develop an OPE index to estimate the climate sensitivity to astronomical forcing. They also show that obliquity and precession have different weight on the annual mean temperature and precipitation of different latitudinal zones, leading to varying phasing of these climate variables between different latitudes. However, the variations in boreal summer temperature of different latitudes (except the Southern Ocean) are in phase and are dominated by precession. All the interglacials are shown to be warmer than the natural climate of the present day and of the next centuries during boreal summer and for the annual mean temperature with varying duration and intensity. Such warming is mainly caused by changes in insolation, unlike the present global warming which mainly results from anthropogenic CO2 increase. The exceptionally long duration of MIS-11 is confirmed by our simulations, and it is demonstrated to be related to the long-lasting low eccentricity and high CO2 concentration and to the anti-phase relationship between obliquity maximum and precession minimum during MIS-11. As far as the variations of annual and seasonal temperatures are concerned, both snapshot and transient simulations show that MIS-19 is the best analogue of the present interglacial. MIS-11 is also a decent analogue when the impact of insolation alone is considered, but it is warmer than MIS-1 when the impact of CO2 is additionally included. Due to the large amplitude in the variations of insolation, MIS-5 and MIS-9 can hardly be considered as an analogue of the natural present-day climate and of

  19. The Persistent Eruption of UGC 2773-OT: finally, a decade-long extragalactic Eta Carinae analogue

    NASA Astrophysics Data System (ADS)

    Smith, Nathan; Andrews, Jennifer E.; Mauerhan, Jon C.; Zheng, WeiKang; Filippenko, Alexei V.; Graham, Melissa L.; Milne, Peter

    2016-02-01

    While supernova (SN) impostors resemble the Great Eruption of η Carinae in the sense that their spectra show narrow H lines and they have typical peak absolute magnitudes of -13 to -14 mag, most extragalactic events observed so far are quite different from η Car in duration. Their bright phases typically last for ˜100 d or less, rather than persisting for several years. The transient object UGC 2773-OT (discovered in 2009) had a similar peak absolute magnitude to other SN impostors, but with a gradual 5-yr pre-discovery rise. In the ˜6 yr since discovery, it has faded very slowly (0.26 mag yr-1). Overall, we suggest that its decade-long eruption is so far the best-known analogue of η Car's 19th century eruption. We discuss extensive spectroscopy of the ongoing eruption. The spectra show interesting changes in velocity and line shape that we discuss in detail, including an asymmetric Hα emission line that we show is consistent with the ejection of a bipolar nebula that could be very much like the Homunculus of η Car. Moreover, changes in the line width, line profile, blue excess emission resembling that of Type IIn SNe, and the intensity of Hα suggest the presence of strong circumstellar interaction in the eruption at late times. This supports the hypothesis that the extended plateau of η Car's eruption may have been powered by shock interaction as well. One interesting difference compared to η Car, however, is that UGC 2773-OT so far does not exhibit the repeated brief spikes in luminosity that have been associated with binary periastron events.

  20. The Lyman break analogue Haro 11: spatially resolved chemodynamics with VLT FLAMES

    NASA Astrophysics Data System (ADS)

    James, B. L.; Tsamis, Y. G.; Walsh, J. R.; Barlow, M. J.; Westmoquette, M. S.

    2013-04-01

    Using VLT/Fibre Large Array Multi Element Spectrograph (FLAMES) optical integral field unit observations, we present the first spatially resolved spectroscopic study of the well-known blue compact galaxy Haro 11, thought to be a local analogue to high-redshift Lyman break galaxies. Haro 11 displays complex emission line profiles, consisting of narrow (full width at half-maximum, FWHM ≲ 200 km s-1) and broad (FWHM ˜ 200-300 km s-1) components. We identify three distinct emission knots kinematically connected to one another. A chemodynamical analysis is presented, revealing that spatially resolved ionic and elemental abundances do not agree with those derived from integrated spectra across the galaxy. We conclude that this is almost certainly due to the surface brightness weighting of electron temperature in integrated spectra, leading to higher derived abundances. We find that the eastern knot has a low gas density, but a higher temperature (by ˜4000 K) and consequently an oxygen abundance ˜0.4 dex lower than the neighbouring regions. A region of enhanced N/O is found specifically in Knot C, confirming previous studies that found anomalously high N/O ratios in this system. Maps of the Wolf-Rayet (WR) feature at 4686 Å reveal large WR populations (˜900-1500 stars) in Knots A and B. The lack of WR stars in Knot C combined with an age of ˜7.4 Myr suggests that a recently completed WR phase may be responsible for the observed N/O excess. Conversely, the absence of N-enriched gas and strong WR emission in Knots A and B suggests that we are observing these regions at an epoch where stellar ejecta has yet to cool and mix with the interstellar medium.